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Sample records for chlorella pyrenoidosa efecto

  1. Gas exchange of algae. IV. Reliability of Chlorella pyrenoidosa.

    PubMed

    Ammann, E C; Fraser-Smith, A

    1968-05-01

    A single culture of Chlorella pyrenoidosa (700 ml) was grown continuously under uniform environmental conditions for a period of 11 months. During this time, the culture remained uncontaminated and its oxygen production, carbon dioxide consumption, and photosynthetic quotient (PQ = CO(2)/O(2)) were monitored on a 24-hr basis. The gas exchange characteristics of the alga were found to be extremely reliable; the average oxygen production was 1.21 +/- 0.03 ml per min, the carbon dioxide consumption was 1.09 +/- 0.03 ml per min, and the PQ was 0.90 +/- 0.01 when changes in both lamp intensity and instrument accuracy were taken into consideration. Such long-term dependability in the production of oxygen, consumption of carbon dioxide, and maintenance of a uniform PQ warrants the use of C. pyrenoidosa in a regenerative life support system for space travel.

  2. Genetic diversity analysis with ISSR PCR on green algae Chlorella vulgaris and Chlorella pyrenoidosa

    NASA Astrophysics Data System (ADS)

    Shen, Songdong

    2008-11-01

    In the present study, genetic polymorphism and diversity in unicellular clones of Chlorella vulgaris Beijerinck and Chlorella pyrenoidosa Chick were studied with Inter Simple Sequence Repeats PCR (ISSR PCR). Samples including four clones of C. vulgaris and three clones of C. pyrenoidosa were purified by single-clone-choice method. For four C. vulgaris unicellular clones, the total number of the bands scored for 18 primers was 298; and the number of the polymorphic bands was 118, of which 39.6% were polymorphic. The size of PCR products ranged from 200 to 2 500 bp. The total number of bands scored for 18 primers, the number of polymorphic bands and the percentage of three C. pyrenoidosa unicellular clones was 194.83 and 30.8%, respectively. POPGENE analysis show that the average Nei genetic diversity (h*) and Shannon index of diversity (I*) in the four C. vulgaris unicellular clones was 0.2181 and 0.3208, respectively, which is slightly higher than those of the three C. pyrenoidosa unicellular clones (0.190 3 and 0.274 8), which agreed with the percentage of polymorphic bands in the mixed samples of the two species. The results suggest that ISSR is a useful method to Chlorella for intraspecies genetic analysis.

  3. Interaction of organic solvents with the green alga Chlorella pyrenoidosa

    SciTech Connect

    Stratton, G.W.; Smith, T.M. )

    1988-06-01

    Solvents are often a component of bioassay systems when water-insoluble toxicants are being tested. These solvents must also be considered as xenobiotics and therefore, as potential toxicants in the bioassay. However, the effects of solvents on the organisms being tested and their possible interaction with the test compound are often overlooked by researchers. The purpose of the present study was to compare the inhibitory effects of six solvents commonly used in pesticide bioassays towards growth of the common green alga Chlorella pyrenoidosa, and to examine the occurrence of solvent-pesticide interactions with this organism.

  4. Removal and reductive dechlorination of triclosan by Chlorella pyrenoidosa.

    PubMed

    Wang, Shujuan; Wang, Xian; Poon, Karen; Wang, Yini; Li, Shangfu; Liu, Hongxia; Lin, Shuhai; Cai, Zongwei

    2013-09-01

    Triclosan that is widely used as antimicrobial agent has been detected as contaminant in various aquatic environments. In this work, removal and biodegradation of triclosan in water by using a ubiquitous green alga, Chlorella pyrenoidosa was investigated. When C. pyrenoidosa was exposed to a series concentration of triclosan from 100 to 800ngmL(-1), more than 50% of triclosan was eliminated by algal uptake from the culture medium during the first 1h exposure and reached equilibrium after the 6h treatment. In the biodegradation experiments, a removal percentage of 77.2% was obtained after C. pyrenoidosa was cultivated with 800ngmL(-1) triclosan for 96h. A major metabolite from the reductive dechlorination of triclosan was identified by using liquid chromatography coupled with electrospray ionization-mass spectrometry. The ultrastructural morphology of algal cells grown in the presence of triclosan was observed by using transmission electron microscopy and the growth of algal cells was detected. It was found that the trilcosan treatment resulted in the disruption of the chloroplast and the release of organic material into aquatic environment, which indicated that triclosan may affect membrane metabolism.

  5. Aluminum bioavailability to the green alga Chlorella pyrenoidosa in acidified synthetic soft water

    SciTech Connect

    Parent, L.; Campbell, P.G.C. )

    1994-04-01

    A unicellular green alga, Chlorella pyrenoidosa, was exposed to inorganic Al under controlled experimental conditions to determine whether the biological response elicited by the dissolved metal could be predicted from the free-metal ion concentration, [Al[sup 3+

  6. Enantioselective toxic effects of cyproconazole enantiomers against Chlorella pyrenoidosa.

    PubMed

    Zhang, Wenjun; Cheng, Cheng; Chen, Li; Di, Shanshan; Liu, Chunxiao; Diao, Jinling; Zhou, Zhiqiang

    2016-09-01

    Enantioselectivity in ecotoxicity, digestion and uptake of chiral pesticide cyproconazole to Chlorella pyrenoidosa was studied. The 96h-EC50 values of rac- and the four enantiomers were 9.005, 6.616, 8.311, 4.290 and 9.410 mg/L, respectively. At the concentrations of 8 mg/L and 14 mg/L, the contents of pigments exposed in rac-, enantiomer-2 and 4 were higher than that exposed in enantiomer-1 and 3. The superoxide dismutase (SOD) and catalase (CAT) activity of algae exposed to enantiomer-1 and 3 was higher than that exposed to the rac-, enantiomer-2 and 4 at three levels. In addition, the malondialdehyde (MDA) concentrations in algae disposed with enantiomer-1 and 3 were increased remarkably at three levels. For the digestion experiment, the half-lives of four enantiomers in algae suspension were 28.06, 19.10, 21.13, 15.17 days, respectively. During the uptake experiment, the order of the concentrations of cyproconazole in algae cells was enantiomer-4, 2, 3 and 1. Based on these data, we concluded that ecotoxicity, digestion and uptake of chiral pesticide cyproconazole to C. pyrenoidosa were enantioselective, and such enantiomeric differences must be taken into consideration when assessing the risk of cyproconazole to environment. PMID:27268794

  7. Kinetics of phthalate ester biodegradation by Chlorella pyrenoidosa

    SciTech Connect

    Yan, H.; Ye, C.; Yin, C.

    1995-06-01

    Experimental results show that Chlorella pyrenoidosa has an ability to accumulate and biodegrade phthalate esters. Bioconcentration factors of dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP) reached their maxima of 162 at 24 h, 205 at 12 h, and 4,077 at 12 h. The average biodegradation rates of DMP, DEP, and DBP per day were found to be 13.4 mg/L, 7.3 mg/L, and 2.1 mg/L, respectively. Based on the experimental data, a second-order kinetic equation was formulated as {minus}dC/dt = KNr, with a factor r indicating the rate of algal growth. Calculation of this equation fits well with the observed data, and the standard deviations between calculated and observed values were 1.72 mg/L, 1.80 mg/L, and 0.26 mg/L for DMP, DEP, DBP, respectively.

  8. Preventing dyslipidemia by Chlorella pyrenoidosa in rats and hamsters after chronic high fat diet treatment.

    PubMed

    Cherng, Jong-Yuh; Shih, Mei-Fen

    2005-05-13

    The effects of Chlorella pyrenoidosa on serum lipid profiles, after concomitant long-term treatment of high-fat diet (HFD) in rats and hamsters was studied. Wistar rats and Syrian hamsters were fed with or without various concentrations of Chlorella pyrenoidosa contained high-fat diet (CHFD) for 2, 4 and 8 weeks prior to assay of serum lipids. Fasting triglycerides, total cholesterol, and LDL cholesterol as well as HDL cholesterol levels in high-fat diet treated rats and hamster were determined. Results showed that triglycerides, total cholesterol and LDL cholesterol levels in HFD treated rats and hamsters were increased from the normal rodent diet (NRD) treated controls after 2, 4, and 8-week treatments. However, the presence of Chlorella pyrenoidosa in high-fat diets significantly decreased the levels of triglycerides, total cholesterol and LDL cholesterol with comparison to HFD group in rats and hamsters. The total cholesterol/HDL ratios, an indication of occurrence of coronary heart disease, were decreased in all CHFD treated grouped rats and hamsters which suggests administration of Chlorella pyrenoidosa could lower the occurring risk of heart diseases. In conclusion, Chlorella pyrenoidosa has the ability to prevent dyslipidemia in chronic high-fat fed animals and could be potential in use to prevent intestinal absorption of redundant lipid from our daily intake and subsequently to prevent hyperlipidemia as well as atherosclerosis. PMID:15850594

  9. Application of ozonated piggery wastewater for cultivation of oil-rich Chlorella pyrenoidosa.

    PubMed

    Gan, Ke; Mou, Xiaoqing; Xu, Yan; Wang, Haiying

    2014-11-01

    Ozonated and autoclaved piggery wastewaters were compared for cultivation of oil-rich Chlorella pyrenoidosa by measuring nutrient removal from the medium and growth rate and lipid production of the microalgae. The removal rates of chemical oxygen demand, NH4(+)-N, total nitrogen and total phosphorus by C. pyrenoidosa were not influenced by both sterilisation methods. The specific growth rate and biomass of C. pyrenoidosa were determined by analysing the chlorophyll concentration for eliminating the disturbance of bacteria growth in culture system. Bacteria raised from the residue in the ozonated medium achieved 30% of the total microorganisms at the end of cultivation. They reduced the growth of C. pyrenoidosa by 10.4%, but contributed to a faster decline of the nutrient content on the first day. Lipid production and fatty acid profile did not change markedly in both sterilisation methods. The results suggest that ozonation is acceptable for piggery wastewater treatment for C. pyrenoidosa cultivation.

  10. Gastrointestinal Elimination of Perfluorinated Compounds Using Cholestyramine and Chlorella pyrenoidosa

    PubMed Central

    Genuis, Stephen J.; Curtis, Luke; Birkholz, Detlef

    2013-01-01

    Background. While perfluorinated compounds (PFCs) are a family of commonly used synthetic compounds with many applications, some PFCs remain persistent within the human body due, in part, to enterohepatic recirculation and renal tubular reabsorption. With increasing recognition of potential harm to human health associated with PFC bioaccumulation, interventions to facilitate elimination of these toxicants are welcome in order to potentially preclude or overcome illness. Minimal research has been undertaken thus far on methods to accelerate human clearance of PFCs. Methods. To test for possible oral treatments to hasten PFC elimination, a group of individuals with elevated PFC levels was treated with cholestyramine (CSM) and, after a break, was subsequently treated with Chlorella pyrenoidosa (CP). Stool samples were collected from all participants (i) prior to any treatment, (ii) during treatment with CSM, and (iii) during treatment with CP. Results. With CSM treatment, significant levels of three distinct PFCs were found in all stools, while levels were mostly undetectable prior to treatment. Following treatment with oral CP, undetectable or very low levels of all PFCs were noted in each sample tested. Conclusion. CSM appears to facilitate elimination of some common PFCs and may have some role in the clinical management of patients with accrued PFCs. PMID:24106616

  11. The pathway of glycollate utilization in Chlorella pyrenoidosa.

    PubMed

    Lord, J M; Merrett, M J

    1970-05-01

    1. Exogenous glycollate was rapidly metabolized in both the light and the dark by photoautotrophically grown Chlorella pyrenoidosa. 2. The incorporation of (14)C from [1-(14)C]glycollate by these cells was inhibited by the tricarboxylic acid-cycle inhibitors monofluoroacetate, diethylmalonate and arsenite, and also by alpha-hydroxypyrid-2-ylmethanesulphonate and isonicotinylhydrazine. 3. Short-term kinetic experiments showed over 80% of the total (14)C present in the soluble fraction from the cells to be in glycine and serine after 10s. This percentage decreased with time whereas the percentage radioactivity in glycerate increased for up to 30s then remained steady. The percentage of the total radioactivity present in citrate increased over the experimental period. Malate was the only other tricarboxylic acid-cycle intermediate to become labelled. 4. The kinetic and inhibitor experiments supported the following pathway of glycollate incorporation: glycollate --> glyoxylate --> glycine --> serine --> hydroxypyruvate --> glycerate --> 3-phosphoglycerate --> 2-phosphoglycerate --> phosphoenolpyruvate --> pyruvate --> acetyl-CoA. 5. The specific activities of the enzymes catalysing this metabolic sequence in cell-free extracts were great enough to account for the observed rate of glycollate metabolism of 0.25mumol/h per mg dry wt. of cells in the light.

  12. [Effects of light quality on the growth characteristics and biochemical component of Chlorella pyrenoidosa].

    PubMed

    Tang, Qing-Qing; Fang, Zhi-Guo; Ji, Wen-Wen; Xia, Hui-Long

    2014-11-01

    Effect of light quality, including red light, blue light, white light, red and blue mixing light with ratios of 8: 1, 8:2 and 8 : 3, on the growth characteristics and biochenmical composition of Chlorella pyrenoidosa was investigated based on light emitting diode (LED). Results showed that Chlorella pyrenoidosa grew best under blue light, and the optical density, specific growth rate and biomass of Chlorella pyrenoidosa was about 2.4, 0.10 d(-1) and 0.64 g x L(-1), respectively, while the optical density of Chlorella pyrenoidosa was between 1.0 and 1.7, the specific growth rate was between 0.07-0.10 d(-1) and the biomass was between 0.27 and 0.38 g x L(-1) under other light quality after 30 days of cultivation. Under blue light, the optical density, specific growth rate and biomass of Chlorella pyrenoidosa was approximately 2.05 times, 1.33 times and 2.06 times higher than red light, respectively. Moreover, red and blue mixing light was conducive to the synthesis of chlorophyll a and β-carotene of Chlorella pyrenoidosa, and blue light could promote the synthesis of chlorophyll b. Chlorophyll a and carotenoids content of Chlorella pyrenoidosa was 13.5 mg xg(-1) and 5.8 mg x g(-1) respectively under red and blue mixing light with a ratio of 8:1, while it was 8.4 mg x g(-1) and 3.6 mg x g(-1) respectively under blue light. Red and blue mixing light was more conducive to protein and total lipid content per dry cell of Chlorella pyrenoidosa. Protein and total lipid content was 489.3 mg x g(-1) and 311.2 mg x g(-1) under red and blue mixing light with a ratio of 8 : 3, while it was 400.9 mg x g(-1) and 231.9 mg x g(-1) respectively under blue light.

  13. Two stage treatment of dairy effluent using immobilized Chlorella pyrenoidosa

    PubMed Central

    2013-01-01

    Background Dairy effluents contains high organic load and unscrupulous discharge of these effluents into aquatic bodies is a matter of serious concern besides deteriorating their water quality. Whilst physico-chemical treatment is the common mode of treatment, immobilized microalgae can be potentially employed to treat high organic content which offer numerous benefits along with waste water treatment. Methods A novel low cost two stage treatment was employed for the complete treatment of dairy effluent. The first stage consists of treating the diary effluent in a photobioreactor (1 L) using immobilized Chlorella pyrenoidosa while the second stage involves a two column sand bed filtration technique. Results Whilst NH4+-N was completely removed, a 98% removal of PO43--P was achieved within 96 h of two stage purification processes. The filtrate was tested for toxicity and no mortality was observed in the zebra fish which was used as a model at the end of 96 h bioassay. Moreover, a significant decrease in biological oxygen demand and chemical oxygen demand was achieved by this novel method. Also the biomass separated was tested as a biofertilizer to the rice seeds and a 30% increase in terms of length of root and shoot was observed after the addition of biomass to the rice plants. Conclusions We conclude that the two stage treatment of dairy effluent is highly effective in removal of BOD and COD besides nutrients like nitrates and phosphates. The treatment also helps in discharging treated waste water safely into the receiving water bodies since it is non toxic for aquatic life. Further, the algal biomass separated after first stage of treatment was highly capable of increasing the growth of rice plants because of nitrogen fixation ability of the green alga and offers a great potential as a biofertilizer. PMID:24355316

  14. Stress response of Chlorella pyrenoidosa to nitro-aromatic compounds.

    PubMed

    Xu, Chang; Wang, Ruihua; Zhang, Y F; Cheng, P; Choi, Martin M F; Poon, Karen

    2015-03-01

    Handling of two nitro-aromatic compounds, 4-nitroaniline (4NA) and 4-nitrophenol (4NP), simultaneously by Chlorella pyrenoidosa was investigated. Algae would secrete or degrade nitro-aromatic compounds depending on different environmental conditions, in which the mode of handling was determined by the relative formation and degradation rate of the compound. Repeated intermittent trigger with externally added 4NA would induce the continuous secretion of 4NA by algae. Simultaneous exposure of both 4NA and 4NP to algae at normal condition would induce the algae to secrete both compounds. An increase in 4NA exposure concentration would elevate both 4NA and 4NP secretion, and that would be inhibited by the stress conditions of starving or lack of oxygen. Increased 4NA degradation per production rate induced by starving or lack of oxygen might explain the subsequent decrease in 4NA secretion in the presence of 4NP in algae. For 4NP in the presence of 4NA, secretion at normal condition was completely stopped and turned to degradation mode in stress conditions. The decreased formation and increased degradation of 4NP during starving for replenishing energy would explain the net degradation of 4NP in starving condition. The condition of lack of oxygen would inhibit the 4NP formation from 4NA via oxidative deamination, while the degradation of 4NP might not be significantly affected because alternative pathway of degradation via nitro-reduction was available. It may lead to the degradation rate exceeding the formation and explain the net degradation of 4NP in the condition of lack of oxygen.

  15. [Study on the Chlorella pyrenoidosa cultivation technology based on the excess sludge utilization].

    PubMed

    Ji, Wen-Wen; Xia, Hui-Long; Fang, Zhi-Guo; Liu, Hui-Jun

    2013-02-01

    Microalgae cultivation based on the waste water or other reused waste can not only make rational use of the waste, but also provide cheap materials for microalgae production. In the present study, Chlorella pyrenoidosa was used to develop a new way for microalgae cultivation based on the mix culture media with different ratio of sludge extracts and SE (selenite enrichment). Results showed that after 14 d cultivation under the same cultivating condition, the absorbency of C. pyrenoidosa at 680 nm was 0. 858 and 0. 845, respectively, when the ratio between culture medium of SE and sludge extracts was 1:9 and 2:8, and the absorbency at 680 nm was 0.247 and 0.571, respectively, when the ratio between culture medium of SE and sludge extracts was 0:10 and 10:0. Our results also demonstrated that highest content of chlororphyll, beta-carotene and protein was achieved in C. pyrenoidosa cultivated in the mix medium between SE and sludge extracts with the ratio of 2: 8. Therefore, sludge extracts can be used as a good medium to cultivate C. pyrenoidosa, and the C. pyrenoidosa grew much better in this mix medium than in SE medium. In this study, the best condition for C. pyrenoidosa cultivation was achieved in the mix medium with 80% sludge extracts, and C. pyrenoidosa grew very well and the content of chlororphyll and protein was also high in the microalgae cell in this mixture medium. PMID:23668132

  16. Treating sewage using coimmobilized system of Chlorella pyrenoidosa and activated sludge.

    PubMed

    Xiong, Z H; Ma, H J; Huang, G L; Pan, H; Sun, C Z

    2007-01-01

    Chlorella pyrenoidosa was coimmobilized with activated sludge to produce algae-bacteria beads for sewage treatment. Hydrolysis/acidogenesis pretreatment could improve the symbiotic microenvironment of coimmobilized Chlorella pyrenoidosa and activated sludge, and as a result, promote the removal of nutrients (COD(cr), inorganic nitrogen and inorganic phosphorus) in the sewage. A photo-bioreactor combining hydrolysis/acidogenesis pretreatment and coimmobilized technique was designed to treat sewage continuously. The results show that, the removal efficiencies of COD(cr), NH4(+)-N and TP reached steady state after 4-days of experiment. The removal efficiencies of COD(cr), NH4(+)-N and TP were 59.6%, 59.0% and 60.3% respectively.

  17. Hydrothermal liquefaction of Chlorella pyrenoidosa for bio-oil production over Ce/HZSM-5.

    PubMed

    Xu, Yufu; Zheng, Xiaojing; Yu, Huiqiang; Hu, Xianguo

    2014-03-01

    This paper investigated a novel hydrothermal liquefaction process of Chlorella pyrenoidosa catalyzed by Ce/HZSM-5. The chemical groups and components of the residues of C. pyrenoidosa were analyzed by Fourier transform infrared spectrometry and Gas Chromatograph-Mass Spectrometer. The crystal structure and micro surface topography of C. pyrenoidosa before and after catalytic liquefaction were characterized by X-ray diffraction and Scanning electron microscopy, respectively. The experimental results showed that the catalytic cracking effects of Ce/HZSM-5 were superior to that of HZSM-5 as a liquefaction catalyst of C. pyrenoidosa. Compared with HZSM-5, Ce/HZSM-5 has a significantly enhanced Lewis acid active center, smaller particle size, larger specific surface, and highly dispersed Ce4O7 with trivalent and tetravalent cerium in the zeolite skeleton channel that accelerate the catalytic liquefaction of C. pyrenoidosa. The rare earth modified zeolite Ce/HZSM-5 exhibits good potential and a beneficial nature for the preparation of bio-oil from microalgae with high efficiency. PMID:24472700

  18. Hydrothermal liquefaction of Chlorella pyrenoidosa for bio-oil production over Ce/HZSM-5.

    PubMed

    Xu, Yufu; Zheng, Xiaojing; Yu, Huiqiang; Hu, Xianguo

    2014-03-01

    This paper investigated a novel hydrothermal liquefaction process of Chlorella pyrenoidosa catalyzed by Ce/HZSM-5. The chemical groups and components of the residues of C. pyrenoidosa were analyzed by Fourier transform infrared spectrometry and Gas Chromatograph-Mass Spectrometer. The crystal structure and micro surface topography of C. pyrenoidosa before and after catalytic liquefaction were characterized by X-ray diffraction and Scanning electron microscopy, respectively. The experimental results showed that the catalytic cracking effects of Ce/HZSM-5 were superior to that of HZSM-5 as a liquefaction catalyst of C. pyrenoidosa. Compared with HZSM-5, Ce/HZSM-5 has a significantly enhanced Lewis acid active center, smaller particle size, larger specific surface, and highly dispersed Ce4O7 with trivalent and tetravalent cerium in the zeolite skeleton channel that accelerate the catalytic liquefaction of C. pyrenoidosa. The rare earth modified zeolite Ce/HZSM-5 exhibits good potential and a beneficial nature for the preparation of bio-oil from microalgae with high efficiency.

  19. [Optimization of Chlorella pyrenoidosa-15 photoheterotrophic culture and its use in wastewater treatment].

    PubMed

    Wang, Xiu-jin; Li, Zhao-sheng; Xing, Guan-lan; Li, Zhuo-ning; Yuan, Hong-li; Yang, Jin-shui

    2012-08-01

    To improve the biomass and lipid productivity of the microalgae Chlorella pyrenoidosa-15, the carbon and nitrogen sources were screened to culture it heterotrophically. The best carbon and nitrogen sources were glucose and soy peptone, respectively. The carbon and nitrogen concentrations were optimized with the help of response surface design. The maximum biomass productivity was predicted to be 0.62 g x (L x d)(-1) with glucose and soy peptone concentrations of 17.53 g x L(-1) and 8.67 g x L(-1), respectively. The results of response surface design were validated with biomass productivity of 0.63 g x (L x d)(-1) and lipid content of 19.25%. The lipid productivity reached 121.3 mg x (L x d)(-1). In the research of Chlorella pyrenoidosa-15 cultured in non-autoclaved Beijing urban wastewater, the maximum algae biomass dry weight of 1.00 g x L(-1) was achieved with a lipid content of 24.12%. Results also showed that the treatment using Chlorella pyrenoidosa-15 effectively reduced the COD values and total nitrogen content in the wastewater, with a COD degradation rate of 80.9%, and a 69% decrease in total nitrogen content. PMID:23213898

  20. Ultrasound-Enhanced Subcritical CO2 Extraction of Lutein from Chlorella pyrenoidosa.

    PubMed

    Fan, Xiao-Dan; Hou, Yan; Huang, Xing-Xin; Qiu, Tai-Qiu; Jiang, Jian-Guo

    2015-05-13

    Lutein is an important pigment of Chlorella pyrenoidosa with many beneficial functions in human health. The main purpose of this study was to extract lutein from C. pyrenoidosa using ultrasound-enhanced subcritical CO2 extraction (USCCE). Effects of operating conditions on the extraction, including extraction pretreatment, temperature, pressure, time, CO2 flow rate, and ultrasonic power, were investigated, and an orthogonal experiment was designed to study the effects of extraction pressure, temperature, cosolvent amount, and time on the extraction yields. The USCCE method was compared with other extraction methods in terms of the yields of lutein and the microstructure of C. pyrenoidosa powder by scanning electron microscopy. A maximal extraction yield of 124.01 mg lutein/100 g crude material was achieved under optimal conditions of extraction temperature at 27 °C, extraction pressure at 21 MPa, cosolvent amount at 1.5 mL/g ethanol, and ultrasound power at 1000 W. Compared to other methods, USCCE could significantly increase the lutein extraction yield at lower extraction temperature and pressure. Furthermore, the kinetic models of USCCE and subcritical CO2 extraction (SCCE) of lutein from C. pyrenoidosa were set as E = 130.64 × (1 - e(-0.6599t)) and E = 101.82 × (1 - e(-0.5683t)), respectively. The differences of parameters in the kinetic models indicate that ultrasound was able to enhance the extraction process of SCCE.

  1. Green algae (Chlorella pyrenoidosa) adsorbs Bacillus thurigiensis (Bt) toxin, Cry1Ca insecticidal protein, without an effect on growth.

    PubMed

    Wang, Jiamei; Chen, Xiuping; Li, Yunhe; Su, Changqing; Ding, Jiatong; Peng, Yufa

    2014-08-01

    The effect of purified Cry1Ca insecticidal protein on the growth of Chlorella pyrenoidosa was studied in a three-generation toxicity test. The C. pyrenoidosa medium with a density of 5.4 × 10(5) cells/mL was subcultured for three generations with added Cry1Ca at 0, 10, 100, and 1000 µg/L, and cell numbers were determined daily. To explore the distribution of Cry1Ca in C. pyrenoidosa and the culture medium, Cry1Ca was added at 1000 µg/L to algae with a high density of 4.8 × 10(6) cells/mL, and Cry1Ca content was determined daily in C. pyrenoidosa and the culture medium by enzyme-linked immunosorbent assays. Our results showed that the growth curves of C. pyrenoidosa exposed to 10, 100, and 1000 µg/L of Cry1Ca almost overlapped with that of the blank control, and there were no statistically significant differences among the four treatments from day 0 to day 7, regardless of generation. Moreover, the Cry1Ca content in the culture medium and in C. pyrenoidosa sharply decreased under exposure of 1000 µg/L Cry1Ca with high initial C. pyrenoidosa cell density. The above results demonstrate that Cry1Ca in water can be rapidly adsorbed and degraded by C. pyrenoidosa, but it has no suppressive or stimulative effect on algae growth.

  2. Inhibitory effects of terpene alcohols and aldehydes on growth of green alga Chlorella pyrenoidosa

    SciTech Connect

    Ikawa, Miyoshi; Mosley, S.P.; Barbero, L.J. )

    1992-10-01

    The growth of the green alga Chlorella pyrenoidosa was inhibited by terpene alcohols and the terpene aldehyde citral. The strongest activity was shown by citral. Nerol, geraniol, and citronellol also showed pronounced activity. Strong inhibition was linked to acyclic terpenes containing a primary alcohol or aldehyde function. Inhibition appeared to be taking place through the vapor phase rather than by diffusion through the agar medium from the terpene-treated paper disks used in the system. Inhibition through agar diffusion was shown by certain aged samples of terpene hydrocarbons but not by recently purchased samples.

  3. Efficacy of Chlorella pyrenoidosa and Scenedesmus abundans for Nutrient Removal in Rice Mill Effluent (Paddy Soaked Water).

    PubMed

    Abinandan, S; Bhattacharya, Ribhu; Shanthakumar, S

    2015-01-01

    Microalgae are product of sustainable development owing to its ability to treat variety of wastewater effluents and thus produced biomass can serve as value added product for various commercial applications. This paper deals with the cultivation of microalgae species namely Chlorella pyrenoidosa and Scenedesmus abundans in rice mill effluent (i.e., paddy soaked water) for nutrient removal. In order to investigate the nutrient removal capability, microalgae are subjected to cultivation in both raw and autoclaved samples. The maximum phosphate removal by Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 98.3% and 97.6%, respectively, whereas, the removal of ammoniacal nitrogen by Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 92% and 90.3%, respectively. The growth (measured in terms of chlorophyll content) of Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 3.88 mg/l and 5.55 mg/l, respectively. The results indicate the suitability of microalgae cultivation in rice mill effluent treatment for nutrient removal.

  4. Biodiesel quality and biochemical changes of microalgae Chlorella pyrenoidosa and Scenedesmus obliquus in response to nitrate levels.

    PubMed

    Wu, Hongqin; Miao, Xiaoling

    2014-10-01

    Biodiesel quality associated with biochemical components of Chlorella pyrenoidosa and Scenedesmus obliquus under different nitrate levels were investigated. The highest lipid contents of 54.5% for C. pyrenoidosa and 47.7% for S. obliquus were obtained in nitrate absence. Carbohydrate peaked at 0.3gL(-1) with values of 40.7% for C. pyrenoidosa and 42.5% for S. obliquus. Protein content seemed species dependent, which decreased substantially to 11.2% in C. pyrenoidosa and 8.8% in S. obliquus under nitrate absence in present research. Better biodiesel quality (e.g. cetane number >58, iodine value <69) could be obtained from C. pyrenoidosa in nitrate absence and S. obliquus in 0.3gL(-1), where the highest saturated fatty acids (39.5 for C. pyrenoidosa, 31.2 for S. obliquus) and the lowest unsaturated fatty acids (60.5 for C. pyrenoidosa, 68.8 for S. obliquus) were obtained. These results suggest that microalgae grown in the presence of nitrogen may limit biodiesel quality.

  5. Carbon and Metal Quantum Dots toxicity on the microalgae Chlorella pyrenoidosa.

    PubMed

    Xiao, An; Wang, Chao; Chen, Jiao; Guo, Ruixin; Yan, Zhengyu; Chen, Jianqiu

    2016-11-01

    In this report, we investigated the cytotoxicity of two types of quantum dots(QDs) (carbon quantum dots(CQDs): N, S doped CQDs, N doped CQDs, no doped CQDs; metal QDs(MQDs): CdTe QDs, CdS QDs, CuInS2/ZnS QDs) on Chlorella pyrenoidosa(C. Pyrenoidosa) at different concentrations. We compared the toxicity of different QDs on C. Pyrenoidosa through determination of the algal growth inhibition, acute toxicity tests (EC50), Chlorophyll a(Chla) contents, protein contents, the activity of enzymatic and metabolites contents. When C. Pyrenoidosa was treated by various concentrations of QDs, the Chla contents were consistent to the number of algae cells, showing a good dose-response relationship. At the 96h, the EC50 of N, S doped CQDs, N doped CQDs, no doped CQDs and CdTe QDs, CdS QDs, CuInS2/ZnS QDs were 38.56, 185.83, 232.47, 0.015, 4.88, 459.5mg/l, respectively. The toxicity order of them was: CuInS2/ZnS QDs

  6. Carbon and Metal Quantum Dots toxicity on the microalgae Chlorella pyrenoidosa.

    PubMed

    Xiao, An; Wang, Chao; Chen, Jiao; Guo, Ruixin; Yan, Zhengyu; Chen, Jianqiu

    2016-11-01

    In this report, we investigated the cytotoxicity of two types of quantum dots(QDs) (carbon quantum dots(CQDs): N, S doped CQDs, N doped CQDs, no doped CQDs; metal QDs(MQDs): CdTe QDs, CdS QDs, CuInS2/ZnS QDs) on Chlorella pyrenoidosa(C. Pyrenoidosa) at different concentrations. We compared the toxicity of different QDs on C. Pyrenoidosa through determination of the algal growth inhibition, acute toxicity tests (EC50), Chlorophyll a(Chla) contents, protein contents, the activity of enzymatic and metabolites contents. When C. Pyrenoidosa was treated by various concentrations of QDs, the Chla contents were consistent to the number of algae cells, showing a good dose-response relationship. At the 96h, the EC50 of N, S doped CQDs, N doped CQDs, no doped CQDs and CdTe QDs, CdS QDs, CuInS2/ZnS QDs were 38.56, 185.83, 232.47, 0.015, 4.88, 459.5mg/l, respectively. The toxicity order of them was: CuInS2/ZnS QDs

  7. Interactions of CuO nanoparticles with the algae Chlorella pyrenoidosa: adhesion, uptake, and toxicity.

    PubMed

    Zhao, Jian; Cao, Xuesong; Liu, Xiaoyu; Wang, Zhenyu; Zhang, Chenchen; White, Jason C; Xing, Baoshan

    2016-11-01

    The potential adverse effects of CuO nanoparticles (NPs) have increasingly attracted attention. Combining electron microscopic and toxicological investigations, we determined the adhesion, uptake, and toxicity of CuO NPs to eukaryotic alga Chlorella pyrenoidosa. CuO NPs were toxic to C. pyrenoidosa, with a 72 h EC50 of 45.7 mg/L. Scanning electron microscopy showed that CuO NPs were attached onto the surface of the algal cells and interacted with extracellular polymeric substances (EPS) excreted by the organisms. Transmission electron microscopy (TEM) showed that EPS layer of algae was thickened by nearly 4-fold after CuO NPs exposure, suggesting a possible protective mechanism. In spite of the thickening of EPS layer, CuO NPs were still internalized by endocytosis and were stored in algal vacuoles. TEM and electron diffraction analysis confirmed that the internalized CuO NPs were transformed to Cu2O NPs (d-spacing, ∼0.213 nm) with an average size approximately 5 nm. The toxicity investigation demonstrated that severe membrane damage was observed after attachment of CuO NPs with algae. Reactive oxygen species generation and mitochondrial depolarization were also noted upon exposure to CuO NPs. This work provides useful information on understanding the role of NPs-algae physical interactions in nanotoxicity.

  8. Toxic effects of 1,4-dichlorobenzene on photosynthesis in Chlorella pyrenoidosa.

    PubMed

    Zhang, Jinhua; Wang, Jie; Feng, Jia; Lv, Junping; Cai, Jin; Liu, Qi; Xie, Shulian

    2016-09-01

    1,4-Dichlorobenzene (1,4-DCB) is a common organic contaminant in water. To determine the effects of this contaminant on photosynthesis in the freshwater alga Chlorella pyrenoidosa, algal cells were treated with 1,4-DCB at different concentrations for various times, and their photosynthetic pigment contents and chlorophyll fluorescence traits were analyzed. The results showed that 1,4-DCB exerted toxic effects on photosynthesis in C. pyrenoidosa, especially at concentrations exceeding 10 mg/L. The inhibitory effects of 1,4-DCB were time- and concentration-dependent. After treatment with 1,4-DCB (≥10 mg/L), the contents of photosynthetic pigments decreased significantly, the photosystem II reaction center was irreversibly damaged, and the quantum yield of photosystem II decreased significantly. Also, there were sharp decreases in the efficiency of photosynthetic electron transport and energy conversion. Photosystem II became overloaded as the amount of excitation energy distributed to it increased. All of these events weakened the photochemical reaction, and ultimately led to serious inhibition of photosynthesis. PMID:27542668

  9. Interactions of CuO nanoparticles with the algae Chlorella pyrenoidosa: adhesion, uptake, and toxicity.

    PubMed

    Zhao, Jian; Cao, Xuesong; Liu, Xiaoyu; Wang, Zhenyu; Zhang, Chenchen; White, Jason C; Xing, Baoshan

    2016-11-01

    The potential adverse effects of CuO nanoparticles (NPs) have increasingly attracted attention. Combining electron microscopic and toxicological investigations, we determined the adhesion, uptake, and toxicity of CuO NPs to eukaryotic alga Chlorella pyrenoidosa. CuO NPs were toxic to C. pyrenoidosa, with a 72 h EC50 of 45.7 mg/L. Scanning electron microscopy showed that CuO NPs were attached onto the surface of the algal cells and interacted with extracellular polymeric substances (EPS) excreted by the organisms. Transmission electron microscopy (TEM) showed that EPS layer of algae was thickened by nearly 4-fold after CuO NPs exposure, suggesting a possible protective mechanism. In spite of the thickening of EPS layer, CuO NPs were still internalized by endocytosis and were stored in algal vacuoles. TEM and electron diffraction analysis confirmed that the internalized CuO NPs were transformed to Cu2O NPs (d-spacing, ∼0.213 nm) with an average size approximately 5 nm. The toxicity investigation demonstrated that severe membrane damage was observed after attachment of CuO NPs with algae. Reactive oxygen species generation and mitochondrial depolarization were also noted upon exposure to CuO NPs. This work provides useful information on understanding the role of NPs-algae physical interactions in nanotoxicity. PMID:27345461

  10. Kinetic modeling of growth and lipid body induction in Chlorella pyrenoidosa under heterotrophic conditions.

    PubMed

    Sachdeva, Neha; Kumar, G Dinesh; Gupta, Ravi Prakash; Mathur, Anshu Shankar; Manikandan, B; Basu, Biswajit; Tuli, Deepak Kumar

    2016-10-01

    The aim of the present work was to develop a mathematical model to describe the biomass and (total) lipid productivity of Chlorella pyrenoidosa NCIM 2738 under heterotrophic conditions. Biomass growth rate was predicted by Droop's cell quota model, while changes observed in cell quota (utilization) under carbon excess conditions were used for the modeling and predicting the lipid accumulation rate. The model was simulated under non-limiting (excess) carbon and limiting nitrate concentration and validated with experimental data for the culture grown in batch (flask) mode under different nitrate concentrations. The present model incorporated two modes (growth and stressed) for the prediction of endogenous lipid synthesis/induction and aimed to predict the effect and response of the microalgae under nutrient starvation (stressed) conditions. MATLAB and Genetic Algorithm were employed for the prediction and validation of the model parameters. PMID:27450124

  11. Evidence for cyclic electron flow around photosystem II in Chlorella pyrenoidosa

    SciTech Connect

    Falkowski, P.G.; Fujita, Y.; Ley, A.; Mauzerall, D.

    1986-05-01

    Electron flow around photosystem II was investigated in Chlorella pyrenoidosa. Using a bare platinum O/sub 2/ electrode, simultaneous measurements were made of steady-state photosynthesis in continuous light, the yield of oxygen (Yo/sub 2/) produced by a superimposed saturating xenon flash, and the change in fluorescence yield of a weak flash triggered before and 70 microseconds after the saturating flash. Throughout most of the continuous photosynthesis-irradiance curve, normalized O/sub 2/ flash yields (Yo/sub 2//Yo/sub 2//sub max/) and normalized variable fluorescence yields ..delta..omega/..delta..omega' were linearly correlated with a slope of 1.0. As photosynthetic rates reached light saturation, however, the variable fluorescence yields remained relatively constant while O/sub 2/ flash yields decreased. These results strongly suggest that there is a cyclic electron flow around photosystem II in unpoisoned intact cells at light saturation and supraoptimal light intensities.

  12. Characterization of aqueous phase from the hydrothermal liquefaction of Chlorella pyrenoidosa.

    PubMed

    Gai, Chao; Zhang, Yuanhui; Chen, Wan-Ting; Zhou, Yan; Schideman, Lance; Zhang, Peng; Tommaso, Giovana; Kuo, Chih-Ting; Dong, Yuping

    2015-05-01

    This study investigated the characteristics of aqueous phase from hydrothermal liquefaction of low-lipid microalgae Chlorella pyrenoidosa. The interactions of operating conditions, including reaction temperature, retention time and total solid ratio were evaluated by response surface methodology. The chemical oxygen demand, total nitrogen and total phosphorus were selected as indicators of the property of AP. Results indicated that total solid ratio was found to be the dominant factor affecting the nutrient recovery efficiencies of AP. Based on energy recovery, GC-MS indicated that the AP at two optimized operating conditions (280 °C, 60 min, 35 wt.% and 300 °C, 60 min, 25 wt.%) were observed to have a higher concentration of organic acids (10.35% and 8.34%) while the sample (260 °C, 30 min, 35 wt.%) was observed to have the highest concentration of N&O-heterocyclic compounds (36.16%).

  13. Study of physical chemistry on biosorption of zinc by using Chlorella pyrenoidosa

    NASA Astrophysics Data System (ADS)

    Rezaei, Hassan; Kulkarni, Satish D.; Saptarshi, Praveen G.

    2012-08-01

    Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Biosorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution. Presence of heavy metals in the aquatic system is posing serious problems. Zinc has been used in many industries and removal of Zn ions from waste water is significant. Biosorption is one of the economic methods used for removal of heavy metals. In the present study, the biomass obtained from the dried Chlorella pyrenoidosa was used for evaluating the biosorption characteristics of Zn ions in aqueous solutions. Batch adsorption experiments were performed with this material and it was found that the amount of metal ions adsorbed increased with the increase in the initial metal ion concentration. In this study effect of agitation time, initial metal ion concentration, temperature, pH and biomass dosage were studied. Maximum metal uptake ( q max) observed at pH 5 was 101.11 mg/g. The biosorption followed both Langmuir and Freundlich isotherm model. The adsorption equilibrium was reached in about 1 h. The kinetic of biosorption followed the second-border rate. The biomass could be regenerated using 0.1 M HNO3. A positive value of Δ H° indicated the endothermic nature of the process. A negative value of the free energy (Δ G°) indicated the spontaneous nature of the adsorption process. A positive value of Δ S° showed increased randomness at solid-liquid interface during the adsorption of heavy metals, it also suggests some structural changes in the adsorbate and the adsorbent. FTIR Spectrums of Chlorella pyrenoidosa revealed the presence of hydroxyl, amino, carboxylic and carbonyl groups. The scanning electron micrograph clearly revealed the surface texture and morphology of the biosorbent.

  14. Nutrients removal and lipids production by Chlorella pyrenoidosa cultivation using anaerobic digested starch wastewater and alcohol wastewater.

    PubMed

    Yang, Libin; Tan, Xiaobo; Li, Deyi; Chu, Huaqiang; Zhou, Xuefei; Zhang, Yalei; Yu, Hong

    2015-04-01

    The cultivation of microalgae Chlorella pyrenoidosa (C. pyrenoidosa) using anaerobic digested starch wastewater (ADSW) and alcohol wastewater (AW) was evaluated in this study. Different proportions of mixed wastewater (AW/ADSW=0.176:1, 0.053:1, 0.026:1, v/v) and pure ADSW, AW were used for C. pyrenoidosa cultivation. The different proportions between ADSW and AW significantly influenced biomass growth, lipids production and pollutants removal. The best performance was achieved using mixed wastewater (AW/ADSW=0.053:1, v/v), leading to a maximal total biomass of 3.01±0.15 g/L (dry weight), lipids productivity of 127.71±6.31 mg/L/d and pollutants removal of COD=75.78±3.76%, TN=91.64±4.58% and TP=90.74±4.62%.

  15. Nutrients removal and lipids production by Chlorella pyrenoidosa cultivation using anaerobic digested starch wastewater and alcohol wastewater.

    PubMed

    Yang, Libin; Tan, Xiaobo; Li, Deyi; Chu, Huaqiang; Zhou, Xuefei; Zhang, Yalei; Yu, Hong

    2015-04-01

    The cultivation of microalgae Chlorella pyrenoidosa (C. pyrenoidosa) using anaerobic digested starch wastewater (ADSW) and alcohol wastewater (AW) was evaluated in this study. Different proportions of mixed wastewater (AW/ADSW=0.176:1, 0.053:1, 0.026:1, v/v) and pure ADSW, AW were used for C. pyrenoidosa cultivation. The different proportions between ADSW and AW significantly influenced biomass growth, lipids production and pollutants removal. The best performance was achieved using mixed wastewater (AW/ADSW=0.053:1, v/v), leading to a maximal total biomass of 3.01±0.15 g/L (dry weight), lipids productivity of 127.71±6.31 mg/L/d and pollutants removal of COD=75.78±3.76%, TN=91.64±4.58% and TP=90.74±4.62%. PMID:25638404

  16. Effect of straw leachates from Cry1Ca-expressing transgenic rice on the growth of Chlorella pyrenoidosa.

    PubMed

    Wang, Jiamei; Chen, Xiuping; Li, Yunhe; Zhu, Haojun; Ding, Jiatong; Peng, Yufa

    2014-05-01

    Because of the prevalence of algae in rice paddy fields, they will be exposed to Bacillus thurigiensis (Bt) proteins released from Bt protein-expressing genetically engineered rice. To assess the effects of leachates extracted from Cry1Ca-expressing transgenic rice (T1C-19) straw on the microalga Chlorella pyrenoidosa, the authors added purified Cry1Ca (10 µg/L, 100 µg/L, and 1000 µg/L) and 5 concentrations of diluted extracts (5%, 10%, 20%, 40%, and 80%) from T1C-19 and the nontransformed control strain Minghui 63 (MH63) to the medium of C. pyrenoidosa. The authors found that the growth curves of C. pyrenoidosa treated with purified Cry1Ca overlapped with the medium control; that the order of C. pyrenoidosa growth rates for the T1C-19 leachate concentrations was 5% > 10% > 20% > control > 40% > 80%, and for the MH63 concentrations the order was 5% > 10% > control > 20% > 40% > 80%, but there were no statistical differences between the 20% T1C-19 or 20% MH63 leachate treatment and the medium control on day 8; and that after 7 d of culture, Cry1Ca could be detected in C. pyrenoidosa treated with different concentrations of T1C-19 leachate. The results demonstrated that Cry1Ca protein released from T1C-19 rice can be absorbed into C. pyrenoidosa but that purified Cry1Ca and leachates from T1C-19 rice have no obvious adverse effects on the growth of C. pyrenoidosa. PMID:24478192

  17. Direct Biodiesel Production from Wet Microalgae Biomass of Chlorella pyrenoidosa through In Situ Transesterification

    PubMed Central

    Cao, Hechun; Zhang, Zhiling; Wu, Xuwen; Miao, Xiaoling

    2013-01-01

    A one-step process was applied to directly converting wet oil-bearing microalgae biomass of Chlorella pyrenoidosa containing about 90% of water into biodiesel. In order to investigate the effects of water content on biodiesel production, distilled water was added to dried microalgae biomass to form wet biomass used to produce biodiesel. The results showed that at lower temperature of 90°C, water had a negative effect on biodiesel production. The biodiesel yield decreased from 91.4% to 10.3% as water content increased from 0% to 90%. Higher temperature could compensate the negative effect. When temperature reached 150°C, there was no negative effect, and biodiesel yield was over 100%. Based on the above research, wet microalgae biomass was directly applied to biodiesel production, and the optimal conditions were investigated. Under the optimal conditions of 100 mg dry weight equivalent wet microalgae biomass, 4 mL methanol, 8 mL n-hexane, 0.5 M H2SO4, 120°C, and 180 min reaction time, the biodiesel yield reached as high as 92.5% and the FAME content was 93.2%. The results suggested that biodiesel could be effectively produced directly from wet microalgae biomass and this effort may offer the benefits of energy requirements for biodiesel production. PMID:24195081

  18. Direct biodiesel production from wet microalgae biomass of Chlorella pyrenoidosa through in situ transesterification.

    PubMed

    Cao, Hechun; Zhang, Zhiling; Wu, Xuwen; Miao, Xiaoling

    2013-01-01

    A one-step process was applied to directly converting wet oil-bearing microalgae biomass of Chlorella pyrenoidosa containing about 90% of water into biodiesel. In order to investigate the effects of water content on biodiesel production, distilled water was added to dried microalgae biomass to form wet biomass used to produce biodiesel. The results showed that at lower temperature of 90°C, water had a negative effect on biodiesel production. The biodiesel yield decreased from 91.4% to 10.3% as water content increased from 0% to 90%. Higher temperature could compensate the negative effect. When temperature reached 150°C, there was no negative effect, and biodiesel yield was over 100%. Based on the above research, wet microalgae biomass was directly applied to biodiesel production, and the optimal conditions were investigated. Under the optimal conditions of 100 mg dry weight equivalent wet microalgae biomass, 4 mL methanol, 8 mL n-hexane, 0.5 M H2SO4, 120°C, and 180 min reaction time, the biodiesel yield reached as high as 92.5% and the FAME content was 93.2%. The results suggested that biodiesel could be effectively produced directly from wet microalgae biomass and this effort may offer the benefits of energy requirements for biodiesel production.

  19. Experimental and kinetic studies for phycoremediation and dye removal by Chlorella pyrenoidosa from textile wastewater.

    PubMed

    Pathak, Vinayak V; Kothari, Richa; Chopra, A K; Singh, D P

    2015-11-01

    Potential of Chlorella pyrenoidosa was experimentally investigated for phycoremediation and dye removal from textile wastewater (TWW) in batch cultures. Growth of alga was observed at various concentration of textile wastewater (25%, 50%, 75% and 100%) and was found in a range of 8.1-14 μg ml(-1) day(-1). Growth study revealed that alga potentially grows up to 75% concentrated textile wastewater and reduces phosphate, nitrate and BOD by 87%, 82% and 63% respectively. Methylene blue dye (MB) removal was also observed by using dry and wet algal biomass harvested after phycoremediation. Adsorption isotherms (Langmuir and Freundlich) and kinetic models (pseudo first and second order) were applied on adsorption process. Dry algal biomass (DAB) was found more efficient biosorbent with large surface area and showed high binding affinity for MB dye in compare to wet algal biomass (WAB). The RL value for both biosorbent showed feasible adsorption process as the obtained value was between 0 and 1. Pseudo second order kinetic model with high degree of correlation coefficient and low sum of error squares (SSE %) value was found more suitable for representation of adsorption process in case of both biosorbents, however pseudo first order also showed high degree of correlation for both biosorbents. PMID:26349408

  20. Bioconcentration kinetics of hydrophobic chemicals in different densities of Chlorella pyrenoidosa

    SciTech Connect

    Sijm, D.T.H.M.; Broersen, K.W.; Roode, D.F. de; Mayer, P.

    1998-09-01

    Algal density-dependent bioconcentration factors and rate constants were determined for a series of hydrophobic compounds in Chlorella pyrenoidosa. The apparent uptake rate constants of the hydrophobic compounds in algae varied between 200 and 710,000 L/kg/d, slightly increased with hydrophobicity within an experiment, were relatively constant for each algal density, and fitted fairly within existing allometric relationships. The bioavailability of the hydrophobic test compounds was significantly reduced by sorption by algal exudates. The sorption coefficients of the hydrophobic compounds to the algal exudates were between 80 and 1,200 L/kg, and were for most algal densities in the same order of magnitude as the apparent bioconcentration factors to the algae, that is, between 80 and 60,200 L/kg. In typical field situations, however, no significant reduction in bioavailability due to exudates is expected. The apparent elimination rate constants of the hydrophobic compounds were high and fairly constant for each algal density and varied between 2 and 190/d. Because the apparent elimination rate constants were higher than the growth rate constant, and were independent of hydrophobicity, the authors speculated that other factors dominate excretion, such as exudate excretion-enhanced elimination. Bioconcentration factors increased less than proportional with hydrophobicity, i.e., the octanol-water partition coefficient [K{sub ow}]. The role of algal composition in bioconcentration is evaluated. Bioconcentrations (kinetics) of hydrophobic compounds that are determined at high algal densities should be applied with caution to field situations.

  1. Experimental and kinetic studies for phycoremediation and dye removal by Chlorella pyrenoidosa from textile wastewater.

    PubMed

    Pathak, Vinayak V; Kothari, Richa; Chopra, A K; Singh, D P

    2015-11-01

    Potential of Chlorella pyrenoidosa was experimentally investigated for phycoremediation and dye removal from textile wastewater (TWW) in batch cultures. Growth of alga was observed at various concentration of textile wastewater (25%, 50%, 75% and 100%) and was found in a range of 8.1-14 μg ml(-1) day(-1). Growth study revealed that alga potentially grows up to 75% concentrated textile wastewater and reduces phosphate, nitrate and BOD by 87%, 82% and 63% respectively. Methylene blue dye (MB) removal was also observed by using dry and wet algal biomass harvested after phycoremediation. Adsorption isotherms (Langmuir and Freundlich) and kinetic models (pseudo first and second order) were applied on adsorption process. Dry algal biomass (DAB) was found more efficient biosorbent with large surface area and showed high binding affinity for MB dye in compare to wet algal biomass (WAB). The RL value for both biosorbent showed feasible adsorption process as the obtained value was between 0 and 1. Pseudo second order kinetic model with high degree of correlation coefficient and low sum of error squares (SSE %) value was found more suitable for representation of adsorption process in case of both biosorbents, however pseudo first order also showed high degree of correlation for both biosorbents.

  2. Continuous cultivation of Chlorella pyrenoidosa using anaerobic digested starch processing wastewater in the outdoors.

    PubMed

    Chu, Hua-Qiang; Tan, Xiao-Bo; Zhang, Ya-Lei; Yang, Li-Bin; Zhao, Fang-Chao; Guo, Jun

    2015-06-01

    Microalgae cultivation using wastewater might be a suitable approach to support sustainable large-scale biomass production. Its compelling characteristics included the recycling of nutrients and water resources, reducing carbon emissions and harvesting available biomass. In outdoor batch and continuous cultures, Chlorella pyrenoidosa completely adapted to anaerobic digested starch processing wastewater and was the dominant microorganism in the photobioreactor. However, seasonal changes of environmental conditions significantly influenced biomass growth and lipid production. The long-term outdoor operation demonstrated that the biomass concentration and productivity in continuous operations at different hydraulic retention times (HRTs) can be successfully predicted using the kinetic growth parameters obtained from the batch culture. A moderate HRT (4days) in the summer provided the best microalgae and lipid production and achieved relatively high biomass concentrations of 1.29-1.62g/L, biomass productivities of 342.6±12.8mg/L/d and lipids productivities of 43.37±7.43mg/L/d.

  3. Continuous cultivation of Chlorella pyrenoidosa using anaerobic digested starch processing wastewater in the outdoors.

    PubMed

    Chu, Hua-Qiang; Tan, Xiao-Bo; Zhang, Ya-Lei; Yang, Li-Bin; Zhao, Fang-Chao; Guo, Jun

    2015-06-01

    Microalgae cultivation using wastewater might be a suitable approach to support sustainable large-scale biomass production. Its compelling characteristics included the recycling of nutrients and water resources, reducing carbon emissions and harvesting available biomass. In outdoor batch and continuous cultures, Chlorella pyrenoidosa completely adapted to anaerobic digested starch processing wastewater and was the dominant microorganism in the photobioreactor. However, seasonal changes of environmental conditions significantly influenced biomass growth and lipid production. The long-term outdoor operation demonstrated that the biomass concentration and productivity in continuous operations at different hydraulic retention times (HRTs) can be successfully predicted using the kinetic growth parameters obtained from the batch culture. A moderate HRT (4days) in the summer provided the best microalgae and lipid production and achieved relatively high biomass concentrations of 1.29-1.62g/L, biomass productivities of 342.6±12.8mg/L/d and lipids productivities of 43.37±7.43mg/L/d. PMID:25746477

  4. Growth and Metabolism of the Green Alga, Chlorella Pyrenoidosa, in Simulated Microgravity

    NASA Technical Reports Server (NTRS)

    Mills, W. Ronald

    2003-01-01

    The effect of microgravity on living organisms during space flight has been a topic of interest for some time, and a substantial body of knowledge on the subject has accumulated. Despite this, comparatively little information is available regarding the influence of microgravity on algae, even though it has been suggested for long duration flight or occupancy in space that plant growth systems, including both higher plants and algae, are likely to be necessary for bioregenerative life support systems. High-Aspect-Ratio Rotating-Wall Vessel or HARV bioreactors developed at Johnson Space Center provide a laboratory-based approach to investigating the effects of microgravity on cellular reactions. In this study, the HARV bioreactor was used to examine the influence of simulated microgravity on the growth and metabolism of the green alga, Chlorella pyrenoidosa. After the first 2 days of culture, cell numbers increased more slowly in simulated microgravity than in the HARV gravity control; after 7 days, growth in simulated microgravity was just over half (58%) that of the gravity control and at 14 days it was less than half (42%). Chlorophyll and protein were also followed as indices of cell competence and function; as with growth, after 2-3 days, protein and chlorophyll levels were reduced in modeled microgravity compared to gravity controls. Photosynthesis is a sensitive biochemical index of the fitness of photosynthetic organisms; thus, CO2-dependent O2 evolution was tested as a measure of photosynthetic capacity of cells grown in simulated microgravity. When data were expressed with respect to cell number, modeled microgravity appeared to have little effect on CO2 fixation. Thus, even though the overall growth rate was lower for cells cultured in microgravity, the photosynthetic capacity of the cells appears to be unaffected. Cells grown in simulated microgravity formed loose clumps or aggregates within about 2 days of culture, with aggregation increasing over time

  5. Lipid accumulation and biosynthesis genes response of the oleaginous Chlorella pyrenoidosa under three nutrition stressors

    PubMed Central

    2014-01-01

    Background Microalgae can accumulate considerable amounts of lipids under different nutrient-deficient conditions, making them as one of the most promising sustainable sources for biofuel production. These inducible processes provide a powerful experimental basis for fully understanding the mechanisms of physiological acclimation, lipid hyperaccumulation and gene expression in algae. In this study, three nutrient-deficiency strategies, viz nitrogen-, phosphorus- and iron-deficiency were applied to trigger the lipid hyperaccumulation in an oleaginous Chlorella pyrenoidosa. Regular patterns of growth characteristics, lipid accumulation, physiological parameters, as well as the expression patterns of lipid biosynthesis-related genes were fully analyzed and compared. Results Our results showed that all the nutrient stress conditions could enhance the lipid content considerably compared with the control. The total lipid and neutral lipid contents exhibit the most marked increment under nitrogen deficiency, achieving 50.32% and 34.29% of dry cell weight at the end of cultivation, respectively. Both photosynthesis indicators and reactive oxygen species parameters reveal that physiological stress turned up when exposed to nutrient depletions. Time-course transcript patterns of lipid biosynthesis-related genes showed that diverse expression dynamics probably contributes to the different lipidic phenotypes under stress conditions. By analyzing the correlation between lipid content and gene expression level, we pinpoint several genes viz. rbsL, me g6562, accA, accD, dgat g2354, dgat g3280 and dgat g7063, which encode corresponding enzymes or subunits of malic enzyme, ACCase and diacylglycerol acyltransferase in the de novo TAG biosynthesis pathway, are highly related to lipid accumulation and might be exploited as target genes for genetic modification. Conclusion This study provided us not only a comprehensive picture of adaptive mechanisms from physiological perspective, but

  6. Hydrogen evolution as a consumption mode of reducing equivalents in green algal fermentation. [Chlamydomonas reinhardii; Chlorella pyrenoidosa; Chlorococcum minutum

    SciTech Connect

    Ohta, S.; Miyamoto, K.; Miura, Y.

    1987-04-01

    Dark anaerobic fermentation in the green algae Chlamydomonas MGA 161, Chlamydomonas reinhardtii, Chlorella pyrenoidosa, and Chlorococcum minutum was studied. Their isolate, Chlamydomonas MGA 161, was unusual in having high H/sub 2/ but almost no formate. The fermentation pattern in Chlamydomonas MGA 161 was altered by changes in the NaCl or NH/sub 4/Cl concentration. Glycerol formation increased at low (0.1%) and high (7%) NaCl concentrations starch degradation, and formation of ethanol, H/sub 2/, and CO/sub 2/ increased with the addition of NH/sub 4/Cl to above 5 millimolar in N-deficient cells. C. reinhardtii and C.pyrenoidosa exhibited a very similar anaerobic metabolism, forming formate, acetate and ethanol in a ratio of about 2:2:1. C. minimum was also unusual in forming acetate, glycerol, and CO/sub 2/ as its main products, with H/sub 2/, formate, and ethanol being formed in negligible amounts. In the presence of CO, ethanol formation increased twofold in Chlamydomonas MGA 161 and C. reinhardtii, but the fermentation pattern in C. minimum did not change. An experiment with hypophosphite addition showed that dark H/sub 2/ evolution of the Escherichia coli type could be ruled out in Chlamydomonas MGA 161 and C. reinhardtii. Among the green algae investigated, three fermentation types were identified by the distribution pattern of the end products, which reflected the consumption model of reducing equivalents in the cells.

  7. The combined and second exposure effect of copper (II) and chlortetracycline on fresh water algae, Chlorella pyrenoidosa and Microcystis aeruginosa.

    PubMed

    Lu, Lei; Wu, Yixiao; Ding, Huijun; Zhang, Weihao

    2015-07-01

    In the experiment, Chlorella pyrenoidosa and Microcystis aeruginosa were chosen to test the individual, combined and second exposure effect of Cu(2+) and chlortetracycline (CTC). The 96 h EC50s of each test were calculated, with the ranges of 0.972-15.6 μmol/L (Cu(2+)), 29.5-102.5 μmol/L (CTC), 14.4-78.9 μmol/L (mixture). The combined toxicities were evaluated with toxicity units (TU) method. The toxicity of complex of Cu(2+) and chlortetracycline was analyzed using concentration addition (CA) model. In the initial test, the combined effect of the two substances was partly additive to C. pyrenoidosa and antagonistic to M. aeruginosa, while in the second exposure test, the combined effect was synergistic to both algae. The biochemical indicators measured in the experiment included chlorophyll fluorescence (Fv/Fm), MDA content, SOD activity and content of soluble proteins. When under combined stress, the biochemical features of both algae were significantly different between the initial test and the second exposure test.

  8. Effect of temperature on extracellular organic matter (EOM) of Chlorella pyrenoidosa and effect of EOM on irreversible membrane fouling.

    PubMed

    Zhao, Fangchao; Su, Yiming; Tan, Xiaobo; Chu, Huaqiang; Zhang, Yalei; Yang, Libin; Zhou, Xuefei

    2015-12-01

    Extracellular organic matter (EOM) can cause serious membrane fouling during the algae harvesting process. In this study, the secretion of EOM, including bound-EOM (bEOM) and dissolved-EOM (dEOM), by Chlorella pyrenoidosa (C. pyrenoidosa) at different culturing temperatures, and their influences on membrane filtration, have been investigated. The secretion of EOM was markedly reduced at high temperatures. The specific EOM secretion rate (SEOM) reached 831.1 ± 55.3mg/g at the lowest temperatures of 15 °C; in contrast, the SEOM decreased to only 370-442 and 356-406 mg/g with temperature rising above 20-25 and 30-35 °C, respectively. Based on membrane filtration experiments, the influence of EOM on irreversible membrane fouling was studied. In a critical flux experiment, low critical flux (24 L/m(2)h) was observed in a system with a high EOM concentration. The fouled membranes were rinsed by water and then used for continuous filtration, scanning electron microscope (SEM) analysis and fourier transform infrared spectroscopy (FTIR) analysis. The results revealed that there was irreversible membrane fouling caused by EOM, and irreversible membrane fouling can be more serious when an algae solution contains high EOM levels.

  9. Herbicidal effects of harmaline from Peganum harmala on photosynthesis of Chlorella pyrenoidosa: probed by chlorophyll fluorescence and thermoluminescence.

    PubMed

    Deng, Chunnuan; Shao, Hua; Pan, Xiangliang; Wang, Shuzhi; Zhang, Daoyong

    2014-10-01

    The herbicidal effects of harmaline extracted from Peganum harmala seed on cell growth and photosynthesis of green algae Chlorella pyrenoidosa were investigated using chlorophyll a fluorescence and thermoluminescence techniques. Exposure to harmaline inhibited cell growth, pigments contents and oxygen evolution of C. pyrenoidosa. Oxygen evolution was more sensitive to harmaline toxicity than cell growth or the whole photosystem II (PSII) activity, maybe it was the first target site of harmaline. The JIP-test parameters showed that harmaline inhibited the donor side of PSII. Harmaline decreased photochemical efficiency and electron transport flow of PSII but increased the energy dissipation. The charge recombination was also affected by harmaline. Amplitude of the fast phase decreased and the slow phase increased at the highest level of harmaline. Electron transfer from QA(-) to QB was inhibited and backward electron transport flow from QA(-) to oxygen evolution complex was enhanced at 10 μg mL(-1) harmaline. Exposure to 10 μg mL(-1) harmaline caused appearance of C band in thermoluminescence. Exposure to 5 μg mL(-1) harmaline inhibited the formation of proton gradient. The highest concentration of harmaline treatment inhibited S3QB(-) charge recombination but promoted formation of QA(-)YD(+) charge pairs. P. harmala harmaline may be a promising herbicide because of its inhibition of cell growth, pigments synthesis, oxygen evolution and PSII activities.

  10. Cultivation of Chlorella pyrenoidosa in outdoor open raceway pond using domestic wastewater as medium in arid desert region.

    PubMed

    Dahmani, Siham; Zerrouki, Djamal; Ramanna, Luveshan; Rawat, Ismail; Bux, Faizal

    2016-11-01

    Chlorella pyrenoidosa was cultivated in secondary wastewater effluent to assess its nutrient removal capabilities. Wastewaters were obtained from a wastewater treatment plant located in Ouargla, Algeria. The experiments were conducted in winter under natural sunlight in an outdoor open raceway pond situated in the desert area. The highest biomass of the microalgae was found to be 1.71±0.04g/L. Temperatures ranged between 18 and 31°C. The average annual insolation was no less than 3500h with an annual solar irradiance of more than 2000kWh/m(2). Analyses of different parameters including COD, NH4(+)-N and TP were conducted throughout the cultivation period. Their average removal efficiencies were 78%, 95% and 81% respectively. The results demonstrated the potential of nutrient removal by microalgae grown on secondary wastewater in arid areas.

  11. Cultivation of Chlorella pyrenoidosa in outdoor open raceway pond using domestic wastewater as medium in arid desert region.

    PubMed

    Dahmani, Siham; Zerrouki, Djamal; Ramanna, Luveshan; Rawat, Ismail; Bux, Faizal

    2016-11-01

    Chlorella pyrenoidosa was cultivated in secondary wastewater effluent to assess its nutrient removal capabilities. Wastewaters were obtained from a wastewater treatment plant located in Ouargla, Algeria. The experiments were conducted in winter under natural sunlight in an outdoor open raceway pond situated in the desert area. The highest biomass of the microalgae was found to be 1.71±0.04g/L. Temperatures ranged between 18 and 31°C. The average annual insolation was no less than 3500h with an annual solar irradiance of more than 2000kWh/m(2). Analyses of different parameters including COD, NH4(+)-N and TP were conducted throughout the cultivation period. Their average removal efficiencies were 78%, 95% and 81% respectively. The results demonstrated the potential of nutrient removal by microalgae grown on secondary wastewater in arid areas. PMID:27528269

  12. A Comprehensive Study on Chlorella pyrenoidosa for Phenol Degradation and its Potential Applicability as Biodiesel Feedstock and Animal Feed.

    PubMed

    Das, Bhaskar; Mandal, Tapas K; Patra, Sanjukta

    2015-07-01

    The present work evaluates the phenol degradative performance of microalgae Chlorella pyrenoidosa. High-performance liquid chromatography (HPLC) analysis showed that C. pyrenoidosa degrades phenol completely up to 200 mg/l. It could also metabolize phenol in refinery wastewater. Biokinetic parameters obtained are the following: growth kinetics, μ max (media) > μ max (refinery wastewater), K s(media) < K s(refinery wastewater), K I(media) > K I(refinery wastewater); degradation kinetics, q max (media) > q max (refinery wastewater), K s(media) < K s(refinery wastewater), K I(media) > K I(refinery wastewater). The microalgae could cometabolize the alkane components present in refinery wastewater. Fourier transform infrared (FTIR) fingerprinting of biomass indicates intercellular phenol uptake and breakdown into its intermediates. Phenol was metabolized as an organic carbon source leading to higher specific growth rate of biomass. Phenol degradation pathway was elucidated using HPLC, liquid chromatography-mass spectrometry (LC-MS) and ultraviolet-visible (UV-visible) spectrophotometry. It involved both ortho- and meta-pathway with prominence of ortho-pathway. SEM analysis shows that cell membrane gets wrinkled on phenol exposure. Phenol degradation was growth and photodependent. Infrared analysis shows increased intracellular accumulation of neutral lipids opening possibility for utilization of spent biomass as biodiesel feedstock. The biomass after lipid extraction could be used as protein supplement in animal feed owing to enhanced protein content. The phenol remediation ability coupled with potential applicability of the spent biomass as biofuel feedstock and animal feed makes it a potential candidate for an environmentally sustainable process.

  13. Growth kinetics and yield study on Chlorella pyrenoidosa in chemically defined media

    SciTech Connect

    Joung, J.J.; Akin, C.

    1983-01-01

    A Chlorella culture free from heterotrophic bacteria was obtained by eliminating the bacteria with successive use of antibiotics and agar plants. The purified Chlorella was cultured in chemically defined media. Under a photon flux (16.7 mw/cmS) similar to insolation, both heterotrophic and mixotrophic cultures were luxurious but the growth rates of autotrophic cultures were reduced substantially. The Chlorella culture grew most rapidly at 30 C in the absence of heterotrophic bacteria, and the highest specific growth rates were 1.43 x 10 h and 0.46 x 10 h for mixotrophic and autotrophic cultures, respectively. The highest photosynthetic efficiency over its growth period was 2.9% for autotrophic cultures. Elimination of heterotrophic bacteria from Chlorella cultures improved the algal growth rate as well as biomass yield significantly. A parasite of 0.1- m size was identified. The motile microorganism played an important role in the growth of the Chlorella and appeared to be common to green algae. 16 references, 2 tables.

  14. Optimization of phenol degradation by the microalga Chlorella pyrenoidosa using Plackett-Burman Design and Response Surface Methodology.

    PubMed

    Dayana Priyadharshini, S; Bakthavatsalam, A K

    2016-05-01

    Statistical optimization designs were used to optimize the phenol degradation using Chlorella pyrenoidosa. The important factor influencing phenol degradation was identified by two-level Plackett-Burman Design (PBD) with five factors. PBD determined the following three factors as significant for phenol degradation viz. algal concentration, phenol concentration and reaction time. CCD and RSM were applied to optimize the significant factors identified from PBD. The results obtained from CCD indicated that the interaction between the concentration of algae and phenol, phenol concentration and reaction time and algal concentration and reaction time affect the phenol degradation (response) significantly. The predicted results showed that maximum phenol degradation of 97% could be achieved with algal concentration of 4g/L, phenol concentration of 0.8g/L and reaction time of 4days. The predicted values were in agreement with experimental values with coefficient of determination (R(2)) of 0.9973. The model was validated by subsequent experimentations at the optimized conditions.

  15. Assessing the combined effects from two kinds of cephalosporins on green alga (Chlorella pyrenoidosa) based on response surface methodology.

    PubMed

    Guo, Ruixin; Xie, Weishu; Chen, Jianqiu

    2015-04-01

    The present work evaluated the combined effects of cefradine and ceftazidime on the green alga Chlorella pyrenoidosa using response surface methodologies (RSM). After a 48 h-exposure, the population growth rate (PGR), the chlorophyll-a content and the SOD content of the alga increased with increased concentrations of two antibiotics. However, the three responses did not continue to demonstrate significant increases once antibiotic concentrations exceed a moderate level. Three two order polynomial regression equations were obtained to describe well the relationship between the responses of the alga and the two antibiotics' concentration (R(2) = 0.9997, 0.9292 and 0.9039, respectively). Three 3 D-surface graphs and their contour plots showed directly the changing trends of the alga under the combined effects of two antibiotics. This study for the first time employed the RSM in ecotoxicology, which indicated that the RSM should be placed under a feasible and a potential application prospect in toxicity assessment.

  16. Novel salvage of queuine from queuosine and absence of queuine synthesis in Chlorella pyrenoidosa and Chlamydomonas reinhardtii.

    PubMed Central

    Kirtland, G M; Morris, T D; Moore, P H; O'Brian, J J; Edmonds, C G; McCloskey, J A; Katze, J R

    1988-01-01

    Partially purified extracts from Chlorella pyrenoidosa and Chlamydomonas reinhardtii catalyze the cleavage of queuosine (Q), a modified 7-deazaguanine nucleoside found exclusively in the first position of the anticodon of certain tRNAs, to queuine, the base of Q. This is the first report of an enzyme that specifically cleaves a 7-deazapurine riboside. Guanosine is not a substrate for this activity, nor is the epoxide a derivative of Q. We also establish that both algae can incorporate exogenously supplied queuine into their tRNA but lack Q-containing tRNA when cultivated in the absence of queuine, indicating that they are unable to synthesize Q de novo. Although no physiological function for Q has been identified in these algae, Q cleavage to queuine would enable algae to generate queuine from exogenous Q in the wild and also to salvage (and recycle) queuine from intracellular tRNA degraded during the normal turnover process. In mammalian cells, queuine salvage occurs by the specific cleavage of queuine from Q-5'-phosphate. The present data also support the hypothesis that plants, like animals, cannot synthesize Q de novo. PMID:3142853

  17. Assessing the combined effects from two kinds of cephalosporins on green alga (Chlorella pyrenoidosa) based on response surface methodology.

    PubMed

    Guo, Ruixin; Xie, Weishu; Chen, Jianqiu

    2015-04-01

    The present work evaluated the combined effects of cefradine and ceftazidime on the green alga Chlorella pyrenoidosa using response surface methodologies (RSM). After a 48 h-exposure, the population growth rate (PGR), the chlorophyll-a content and the SOD content of the alga increased with increased concentrations of two antibiotics. However, the three responses did not continue to demonstrate significant increases once antibiotic concentrations exceed a moderate level. Three two order polynomial regression equations were obtained to describe well the relationship between the responses of the alga and the two antibiotics' concentration (R(2) = 0.9997, 0.9292 and 0.9039, respectively). Three 3 D-surface graphs and their contour plots showed directly the changing trends of the alga under the combined effects of two antibiotics. This study for the first time employed the RSM in ecotoxicology, which indicated that the RSM should be placed under a feasible and a potential application prospect in toxicity assessment. PMID:25684417

  18. Self-sustainable Chlorella pyrenoidosa strain NCIM 2738 based photobioreactor for removal of Direct Red-31 dye along with other industrial pollutants to improve the water-quality.

    PubMed

    Sinha, Surbhi; Singh, Rachana; Chaurasia, Akhilesh K; Nigam, Subhasha

    2016-04-01

    The genotoxic and carcinogenic effects of diazo dyes from industrial effluents pose a serious environmental threat by contaminating aquatic ecosystem and consequently impact human health. The potential of a diazo dye resistant, self-sustainable photosynthetic green alga Chlorella pyrenoidosa NCIM 2738 provides a viable green technology for an efficient biodegradation of diazo dye Direct Red-31 (DR-31) and overall improvement of water quality. Herein, we for the first time report the degradation of DR-31 using C. pyrenoidosa. Batch experiments were performed to optimize the effect of initial pH, contact time and toxicity-range of DR-31 in order to achieve the optimal conditions for maximum decolourization in continuous cyclic photobioreactor. In batch culture, C. pyrenoidosa exhibited 96% decolourization with 40mgL(-1) dye at pH3. The equilibrium was attained within 30min and the maximum uptake of 30.53mgg(-1) algal biomass was observed during this period. This was found to be fitted well with Langmuir and Freundlich adsorption isotherm. The FT-IR spectra showed a change from -N=N- to N-H suggesting the possible involvement of the azoreductase enzyme. The application of C. pyrenoidosa not only degraded the DR-31 but also improved the quality of water by reducing COD (82.73%), BOD (56.44%), sulphate (54.54%), phosphate (19.88%), and TDS (84.18%) which was further enhanced in continuous cyclic bioreactor treatment. The results clearly showed that C. pyrenoidosa provides an efficient, self-sustainable green technology for decolourization of DR-31 and improved the water quality.

  19. Experiments on the accumulation of lindane (gamma-BHC) by the primary producers Chlorella spec. and Chlorella pyrenoidosa.

    PubMed

    Hansen, P D

    1979-01-01

    Experiments were performed on the accumulation of the pesticide lindane (gamma-isomer of BHC) by two algae with different surfaces. An analytical procedure was developed for the gas chromatographic determinnation of lindane. At room temperature, lindane had a water solubility of 7.8 mg/L in distilled water and 6.7 mg/L in tap water. Under the experimental conditions of 10 to 100 microgram/L, 2.3% of the dissolved lindane was lost through adsorption on the glass walls of the equipment and 0.2% through evaporation. The recovery rate of lindane was 98% for the water samples and more than 90% for Chlorella spec. The tolerance in the gas chromatographic measurements amounted to 1.2%. Investigations on the effect of lindane on the growth of Chlorella spec. revealed irreparable damage to the algae cells through loss of chlorophyll, coagulation, and complete sedimentation at concentrations greater than 300 microgram/L. The experiments on sublethal accumulation showed the development of a state of equilibrium between the amount of lindane per cell and in the surrounding water with lindane concentrations of 10 to 100 microgram/L. The lindane was adsorptively attached to the algal cells within a few hr, and after three days lindane stabilized in the cells. The gelatinous surface of the algae increases the accumulation of lindane. PMID:93882

  20. Nutritional Supplementation with Chlorella pyrenoidosa Lowers Serum Methylmalonic Acid in Vegans and Vegetarians with a Suspected Vitamin B₁₂ Deficiency.

    PubMed

    Merchant, Randall Edward; Phillips, Todd W; Udani, Jay

    2015-12-01

    Since vitamin B12 occurs in substantial amounts only in foods derived from animals, vegetarians and particularly vegans are at risk of developing deficiencies of this essential vitamin. The chlorella used for this study is a commercially available whole-food supplement, which is believed to contain the physiologically active form of the vitamin. This exploratory open-label study was performed to determine if adding 9 g of Chlorella pyrenoidosa daily could help mitigate a vitamin B12 deficiency in vegetarians and vegans. Seventeen vegan or vegetarian adults (26-57 years of age) with a known vitamin B12 deficiency, as evidenced by a baseline serum methylmalonic acid (MMA) level above 270 nmol/L at screening, but who otherwise appeared healthy were enrolled in the study. Each participant added 9 g of C. pyrenoidosa to their daily diet for 60 ± 5 days and their serum MMA, vitamin B12, homocysteine (Hcy) levels as well as mean corpuscular volume (MCV), hemoglobin (Hgb), and hematocrit (Hct) were measured at 30 and 60 days from baseline. After 30 and 60 days, the serum MMA level fell significantly (P < .05) by an average ∼34%. Fifteen of the 17 (88%) subjects showed at least a 10% drop in MMA. At the same time, Hcy trended downward and serum vitamin B12 trended upward, while MCV, Hgb, and Hct appeared unchanged. The results of this work suggest that the vitamin B12 in chlorella is bioavailable and such dietary supplementation is a natural way for vegetarians and vegans to get the vitamin B12 they need.

  1. Nutritional Supplementation with Chlorella pyrenoidosa Lowers Serum Methylmalonic Acid in Vegans and Vegetarians with a Suspected Vitamin B₁₂ Deficiency.

    PubMed

    Merchant, Randall Edward; Phillips, Todd W; Udani, Jay

    2015-12-01

    Since vitamin B12 occurs in substantial amounts only in foods derived from animals, vegetarians and particularly vegans are at risk of developing deficiencies of this essential vitamin. The chlorella used for this study is a commercially available whole-food supplement, which is believed to contain the physiologically active form of the vitamin. This exploratory open-label study was performed to determine if adding 9 g of Chlorella pyrenoidosa daily could help mitigate a vitamin B12 deficiency in vegetarians and vegans. Seventeen vegan or vegetarian adults (26-57 years of age) with a known vitamin B12 deficiency, as evidenced by a baseline serum methylmalonic acid (MMA) level above 270 nmol/L at screening, but who otherwise appeared healthy were enrolled in the study. Each participant added 9 g of C. pyrenoidosa to their daily diet for 60 ± 5 days and their serum MMA, vitamin B12, homocysteine (Hcy) levels as well as mean corpuscular volume (MCV), hemoglobin (Hgb), and hematocrit (Hct) were measured at 30 and 60 days from baseline. After 30 and 60 days, the serum MMA level fell significantly (P < .05) by an average ∼34%. Fifteen of the 17 (88%) subjects showed at least a 10% drop in MMA. At the same time, Hcy trended downward and serum vitamin B12 trended upward, while MCV, Hgb, and Hct appeared unchanged. The results of this work suggest that the vitamin B12 in chlorella is bioavailable and such dietary supplementation is a natural way for vegetarians and vegans to get the vitamin B12 they need. PMID:26485478

  2. The effect of nutrition pattern alteration on Chlorella pyrenoidosa growth, lipid biosynthesis-related gene transcription.

    PubMed

    Fan, Jianhua; Cui, Yanbin; Zhou, Yang; Wan, Minxi; Wang, Weiliang; Xie, Jingli; Li, Yuanguang

    2014-07-01

    Heterotrophy to photoautotrophy transition leads to the accumulation of lipids in Chlorella, which has potential to produce both healthy food and biofuels. Therefore, it is of key interest to study the metabolism shift and gene expression changes that influenced by the transition. Both total and neutral lipids contents were increased rapidly within 48 h after the switch to light environment, from 24.5% and 18.0% to 35.3% and 27.4%, respectively, along with the sharp decline of starch from 42.3% to 10.4% during 24h photoinduction phase. By analyzing the correlation between lipid content and gene expression, results revealed several genes viz. me g3137, me g6562, pepc g6833, dgat g3280 and dgat g7566, which encode corresponding enzymes in the de novo lipid biosynthesis pathway, are highly related to lipid accumulation and might be exploited as target genes for genetic modification. These results represented the feasibility of lipid production through trophic converting cultivation.

  3. Improvement of the energy conversion efficiency of Chlorella pyrenoidosa biomass by a three-stage process comprising dark fermentation, photofermentation, and methanogenesis.

    PubMed

    Xia, Ao; Cheng, Jun; Ding, Lingkan; Lin, Richen; Huang, Rui; Zhou, Junhu; Cen, Kefa

    2013-10-01

    The effects of pre-treatment methods on saccharification and hydrogen fermentation of Chlorella pyrenoidosa biomass were investigated. When raw biomass and biomass pre-treated by steam heating, by microwave heating, and by ultrasonication were used as feedstock, the hydrogen yields were only 8.8-12.7 ml/g total volatile solids (TVS) during dark fermentation. When biomass was pre-treated by steam heating with diluted acid and by microwave heating with diluted acid, the dark hydrogen yields significantly increased to 75.6 ml/g TVS and 83.3 ml/g TVS, respectively. Steam heating with diluted acid is the preferred pre-treatment method of C. pyrenoidosa biomass to improve hydrogen yield during dark fermentation and photofermentation, which is followed by methanogenesis to increase energy conversion efficiency (ECE). A total hydrogen yield of 198.3 ml/g TVS and a methane yield of 186.2 ml/g TVS corresponding to an overall ECE of 34.0% were obtained through the three-stage process (dark fermentation, photofermentation, and methanogenesis).

  4. Glycolate metabolism in low and high CO sub 2 -grown chlorella pyrenoidosa and Pavlova lutheri as determined by sup 18 O-labeling

    SciTech Connect

    de Veau, E.J.; Burris, J.E. )

    1989-11-01

    Photorespiration in Chlorella pyrenoidosa Chick. was assayed by measuring {sup 18}O-labeled intermediates of the glycolate pathway. Glycolate, glycine, serine, and excreted glycolate were isolated and analyzed on a gas chromatograph/mass spectrometer to determine isotopic enrichment. Rates of glycolate synthesis were determined from {sup 18}O-labeling kinetics of the intermediates, pool sizes, derived rate equations, and nonlinear regression techniques. Glycolate synthesis was higher in high CO{sub 2}-grown cells than in air-grown cells when both were assayed under the same O{sub 2} and CO{sub 2} concentrations. Synthesis of glycolate, for both types of cells, was stimulated by high O{sub 2} levels and inhibited by high CO{sub 2} levels. Glycolate synthesis in 1.5% CO{sub 2}-grown Chlorella, when exposed to a 0.035% CO{sub 2} atmosphere, increased from about 41 to 86 nanomoles per milligram chlorophyll per minute when the O{sub 2} concentration was increased from 21 to 40%. Glycolate synthesis in air-grown cells increased from 2 to 6 nanomoles per milligram chlorophyll per minute under the same gas levels. Synthesis was undetectable when either the O{sub 2} concentration was lowered to 2% or the CO{sub 2}-concentration was raised to 1.5%. Glycolate excretion was also sensitive to O{sub 2} and CO{sub 2} concentrations in 1.5% CO{sub 2}-grown cells and the glycolate that was excreted was {sup 18}O-labeled. Air-grown cells did not excrete glycolate under any experimental condition. Indirect evidence indicated that glycolate may be excreted as a lactone in Chlorella. Photorespiratory {sup 18}O-labeling kinetics were determined for Pavlova lutheri, which unlike Chlorella and higher plants did not directly synthesize glycine and serine from glycolate. This alga did excrete a significant proportion of newly synthesized glycolate into the media.

  5. Glycolate Metabolism in Low and High CO2-Grown Chlorella pyrenoidosa and Pavlova lutheri as Determined by 18O-Labeling 1

    PubMed Central

    de Veau, Edward J.; Burris, John E.

    1989-01-01

    Photorespiration in Chlorella pyrenoidosa Chick. was assayed by measuring 18O-labeled intermediates of the glycolate pathway. Glycolate, glycine, serine, and excreted glycolate were isolated and analyzed on a gas chromatograph/mass spectrometer to determine isotopic enrichment. Rates of glycolate synthesis were determined from 18O-labeling kinetics of the intermediates, pool sizes, derived rate equations, and nonlinear regression techniques. Glycolate synthesis was higher in high CO2-grown cells than in air-grown cells when both were assayed under the same O2 and CO2 concentrations. Synthesis of glycolate, for both types of cells, was stimulated by high O2 levels and inhibited by high CO2 levels. Glycolate synthesis in 1.5% CO2-grown Chlorella, when exposed to a 0.035% CO2 atmosphere, increased from about 41 to 86 nanomoles per milligram chlorophyll per minute when the O2 concentration was increased from 21% to 40%. Glycolate synthesis in air-grown cells increased from 2 to 6 nanomoles per milligram chlorophyll per minute under the same gas levels. Synthesis was undetectable when either the O2 concentration was lowered to 2% or the CO2 concentration was raised to 1.5%. Glycolate excretion was also sensitive to O2 and CO2 concentrations in 1.5% CO2-grown cells and the glycolate that was excreted was 18O-labeled. Air-grown cells did not excrete glycolate under any experimental condition. Indirect evidence indicated that glycolate may be excreted as a lactone in Chlorella. Photorespiratory 18O-labeling kinetics were determined for Pavlova lutheri, which unlike Chlorella and higher plants did not directly synthesize glycine and serine from glycolate. This alga did excrete a significant proportion of newly synthesized glycolate into the media. PMID:16667116

  6. Heterotrophic cultivation of Chlorella pyrenoidosa using sucrose as the sole carbon source by co-culture with Rhodotorula glutinis.

    PubMed

    Wang, Shikai; Wu, Yong; Wang, Xu

    2016-11-01

    Heterotrophic cultivation of microalgae is a feasible alternative strategy to avoid the light limitation of photoautotrophic culture, but the heterotrophic utilization of disaccharides is difficult for microalgae. Aimed at this problem, a co-culture system was developed by mix culture of C. pyrenoidosa and R. glutinis using sucrose as the sole carbon source. In this system, C. pyrenoidosa could utilize glucose and fructose which were hydrolyzed from sucrose by R. glutinis. The highest specific growth rate and final cell number proportion of algae was 1.02day(-1) and 45%, respectively, when cultured at the initial algal cell number proportion of 95.24% and the final algal cell density was 111.48×10(6)cells/mL. In addition, the lipid content was also promoted due to the synergistic effects in mix culture. This study provides a novel approach using sucrose-riched wastes for the heterotrophic culture of microalgae and may effectively decrease the cost of carbon source. PMID:27619713

  7. Effects of light-emitting diodes under capped daily energy consumption with combinations of electric power and photoperiod on cultivation of Chlorella pyrenoidosa.

    PubMed

    Li, Jinhao; Bin, Hui; Lin, Jian; Chen, Feng; Miao, Xiaoling

    2016-04-01

    Effects of white light-emitting diodes (LEDs) with different light intensities at photoperiod of 18:6h on Chlorella pyrenoidosa growth were investigated. The microalgae exhibited the highest growth rate 89.0mgL(-1)d(-1) and growth efficiency 97.8mgL(-1)KWh(-1) at 110 and 90μmolm(-2)s(-1), respectively. Based on the discovery of this asynchronous phenomenon between growth rate and growth efficiency, influences of LEDs (red, blue and white) under capped daily energy consumption (0.80KWh d(-1)) with combinations of electric power (33.3, 44.4 and 66.6w) and photoperiod (24:0, 18:6 and 12:12h) were further investigated. The highest growth efficiency 106.4mgL(-1)KWh(-1) and growth rate 85.1mgL(-1)d(-1) were both obtained under white-33.3w-24h. Growth efficiency and growth rate were simultaneously improved 1.1 times through this method above. The order of growth efficiency under different LEDs were white>blue>red.

  8. Effects of light-emitting diodes under capped daily energy consumption with combinations of electric power and photoperiod on cultivation of Chlorella pyrenoidosa.

    PubMed

    Li, Jinhao; Bin, Hui; Lin, Jian; Chen, Feng; Miao, Xiaoling

    2016-04-01

    Effects of white light-emitting diodes (LEDs) with different light intensities at photoperiod of 18:6h on Chlorella pyrenoidosa growth were investigated. The microalgae exhibited the highest growth rate 89.0mgL(-1)d(-1) and growth efficiency 97.8mgL(-1)KWh(-1) at 110 and 90μmolm(-2)s(-1), respectively. Based on the discovery of this asynchronous phenomenon between growth rate and growth efficiency, influences of LEDs (red, blue and white) under capped daily energy consumption (0.80KWh d(-1)) with combinations of electric power (33.3, 44.4 and 66.6w) and photoperiod (24:0, 18:6 and 12:12h) were further investigated. The highest growth efficiency 106.4mgL(-1)KWh(-1) and growth rate 85.1mgL(-1)d(-1) were both obtained under white-33.3w-24h. Growth efficiency and growth rate were simultaneously improved 1.1 times through this method above. The order of growth efficiency under different LEDs were white>blue>red. PMID:26826572

  9. Extraction procedure optimization and the characteristics of dissolved extracellular organic matter (dEOM) and bound extracellular organic matter (bEOM) from Chlorella pyrenoidosa.

    PubMed

    Chu, Huaqiang; Yu, Hong; Tan, Xiaobo; Zhang, Yalei; Zhou, Xuefei; Yang, Libin; Li, Deyi

    2015-01-01

    The influence of extracellular organic matter (EOM) on membrane fouling is important for algae cultivation and harvest. Therefore, a deep understanding of EOM and a systematic extraction process are necessary. In this study, EOM from Chlorella pyrenoidosa was thoroughly studied by using different methods to stratify it into dEOM and bEOM. Among these methods, the centrifugation method was optimized for dEOM extraction, and the heating and NaOH methods were optimized for bEOM extraction. In addition, dEOM and bEOM were compared by using analytical methods to obtain their protein and polysaccharide contents, dissolved organic carbon (DOC) contents, specific UV absorbances (SUVA), zeta potentials, FTIR spectra, EEM fluorescence spectra, hydrophobicities and molecular weights. The dEOM and bEOM both primarily consisted of proteins and polysaccharides and carried negative charges with relatively low SUVAs. The protein/polysaccharide ratios in the bEOM were 6.35 (control), 12.54 (heating) and 7.54 (NaOH) mg mg(-1), which were greater than the ratio of the dEOM (2.93 mg mg(-1)). Furthermore, the hydrophobicity analysis indicated that the bEOM had higher hydrophobic fraction content than the dEOM. However, both types of EOM were more hydrophilic in terms of the DOC. Finally, size fraction analysis indicated that high-MW (>100 kDa) and low-MW fractions (<1 kDa) were the primary components in EOMs. Specifically, a greater high-MW fraction was observed in the bEOM, which primarily consisted of DOC and proteins. In contrast with the proteins, the polysaccharides of the dEOM and bEOM were primarily distributed in the hydrophilic and low-MW fractions. Using comparative analysis, centrifugation at 10,000×g for 10 min was chosen as the best method for extracting dEOM. In contrast, heating at 70°C for 20 min was the best method for extracting bEOM. PMID:25559611

  10. Extraction procedure optimization and the characteristics of dissolved extracellular organic matter (dEOM) and bound extracellular organic matter (bEOM) from Chlorella pyrenoidosa.

    PubMed

    Chu, Huaqiang; Yu, Hong; Tan, Xiaobo; Zhang, Yalei; Zhou, Xuefei; Yang, Libin; Li, Deyi

    2015-01-01

    The influence of extracellular organic matter (EOM) on membrane fouling is important for algae cultivation and harvest. Therefore, a deep understanding of EOM and a systematic extraction process are necessary. In this study, EOM from Chlorella pyrenoidosa was thoroughly studied by using different methods to stratify it into dEOM and bEOM. Among these methods, the centrifugation method was optimized for dEOM extraction, and the heating and NaOH methods were optimized for bEOM extraction. In addition, dEOM and bEOM were compared by using analytical methods to obtain their protein and polysaccharide contents, dissolved organic carbon (DOC) contents, specific UV absorbances (SUVA), zeta potentials, FTIR spectra, EEM fluorescence spectra, hydrophobicities and molecular weights. The dEOM and bEOM both primarily consisted of proteins and polysaccharides and carried negative charges with relatively low SUVAs. The protein/polysaccharide ratios in the bEOM were 6.35 (control), 12.54 (heating) and 7.54 (NaOH) mg mg(-1), which were greater than the ratio of the dEOM (2.93 mg mg(-1)). Furthermore, the hydrophobicity analysis indicated that the bEOM had higher hydrophobic fraction content than the dEOM. However, both types of EOM were more hydrophilic in terms of the DOC. Finally, size fraction analysis indicated that high-MW (>100 kDa) and low-MW fractions (<1 kDa) were the primary components in EOMs. Specifically, a greater high-MW fraction was observed in the bEOM, which primarily consisted of DOC and proteins. In contrast with the proteins, the polysaccharides of the dEOM and bEOM were primarily distributed in the hydrophilic and low-MW fractions. Using comparative analysis, centrifugation at 10,000×g for 10 min was chosen as the best method for extracting dEOM. In contrast, heating at 70°C for 20 min was the best method for extracting bEOM.

  11. Changes of ribulose bisphosphate carboxylase/oxygenase content, ribulose bisphosphate concentration, and photosynthetic activity during adaptation of high-CO/sub 2/ grown cells to low-CO/sub 2/ conditions in Chlorella pyrenoidosa

    SciTech Connect

    Yokota, A.; Canvin, D.T.

    1986-02-01

    Changes of some photosynthetic properties of high-CO/sub 2/ grown cells of Chlorella pyrenoidosa during adaptation to low-CO/sub 2/ conditions have been investigated. The K/sub m/ value of photosynthesis of the high-CO/sub 2/ grown cells for dissolved inorganic carbon was 3.3 millimolar and decreased to 25 to 30 micromolar within 4 hours after transferring to air. In the presence of saturating CO/sub 2/ concentrations the photosynthetic activity of the high-CO/sub 2/ grown cells was 1.5 times as high as that of the low-CO/sub 2/ grown cells. There was a significant rise of the photosynthetic activity during adaptation of the high-CO/sub 2/ grown cells to air, followed by a steady decrease. The activity of ribulose 1,5-bisphosphate carboxylase/oxygenase in both the high and low-CO/sub 2/ grown cells was close to the photosynthetic activity of the cells. The concentration of ribulose 1,5-bisphosphate (RuBP) was higher in the low-CO/sub 2/ adapting and low-CO/sub 2/ grown celsl than in the high-CO/sub 2/ grown cells regardless of the photosynthetic rate. This seems to be due to an increased RuBP regeneration activity during adaptation followed by maintenance of the new higher concentration. The RuBP level always exceeded the concentration of ribulose 1,5-bisphosphate carboxylase/oxygenase RuBP binding sites in both the high- and low-CO/sub 2/ grown cells at any dissolved inorganic carbon concentration.

  12. Glutamic Acid Decarboxylation in Chlorella12

    PubMed Central

    Lane, T. R.; Stiller, Mary

    1970-01-01

    The decarboxylation of endogenous free glutamic acid by Chlorella pyrenoidosa, Marburg strain, was induced by a variety of metabolic poisons, by anaerobic conditions, and by freezing and thawing the cells. The rate of decarboxylation was proportional to the concentration of inhibitor present. Possible mechanisms which relate the effects of the various conditions on glutamate decarboxylation and oxygen consumption by Chlorella are discussed. Images PMID:5429350

  13. Modeling of the redox state dynamics in photosystem II of Chlorella pyrenoidosa Chick cells and leaves of spinach and Arabidopsis thaliana from single flash-induced fluorescence quantum yield changes on the 100 ns-10 s time scale.

    PubMed

    Belyaeva, N E; Schmitt, F-J; Paschenko, V Z; Riznichenko, G Yu; Rubin, A B

    2015-08-01

    The time courses of the photosystem II (PSII) redox states were analyzed with a model scheme supposing a fraction of 11-25 % semiquinone (with reduced [Formula: see text]) RCs in the dark. Patterns of single flash-induced transient fluorescence yield (SFITFY) measured for leaves (spinach and Arabidopsis (A.) thaliana) and the thermophilic alga Chlorella (C.) pyrenoidosa Chick (Steffen et al. Biochemistry 44:3123-3132, 2005; Belyaeva et al. Photosynth Res 98:105-119, 2008, Plant Physiol Biochem 77:49-59, 2014) were fitted with the PSII model. The simulations show that at high-light conditions the flash generated triplet carotenoid (3)Car(t) population is the main NPQ regulator decaying in the time interval of 6-8 μs. So the SFITFY increase up to the maximum level [Formula: see text]/F 0 (at ~50 μs) depends mainly on the flash energy. Transient electron redistributions on the RC redox cofactors were displayed to explain the SFITFY measured by weak light pulses during the PSII relaxation by electron transfer (ET) steps and coupled proton transfer on both the donor and the acceptor side of the PSII. The contribution of non-radiative charge recombination was taken into account. Analytical expressions for the laser flash, the (3)Car(t) decay and the work of the water-oxidizing complex (WOC) were used to improve the modeled P680(+) reduction by YZ in the state S 1 of the WOC. All parameter values were compared between spinach, A. thaliana leaves and C. pyrenoidosa alga cells and at different laser flash energies. ET from [Formula: see text] slower in alga as compared to leaf samples was elucidated by the dynamics of [Formula: see text] fractions to fit SFITFY data. Low membrane energization after the 10 ns single turnover flash was modeled: the ∆Ψ(t) amplitude (20 mV) is found to be about 5-fold smaller than under the continuous light induction; the time-independent lumen pHL, stroma pHS are fitted close to dark estimates. Depending on the flash energy used at 1

  14. Modeling of the redox state dynamics in photosystem II of Chlorella pyrenoidosa Chick cells and leaves of spinach and Arabidopsis thaliana from single flash-induced fluorescence quantum yield changes on the 100 ns-10 s time scale.

    PubMed

    Belyaeva, N E; Schmitt, F-J; Paschenko, V Z; Riznichenko, G Yu; Rubin, A B

    2015-08-01

    The time courses of the photosystem II (PSII) redox states were analyzed with a model scheme supposing a fraction of 11-25 % semiquinone (with reduced [Formula: see text]) RCs in the dark. Patterns of single flash-induced transient fluorescence yield (SFITFY) measured for leaves (spinach and Arabidopsis (A.) thaliana) and the thermophilic alga Chlorella (C.) pyrenoidosa Chick (Steffen et al. Biochemistry 44:3123-3132, 2005; Belyaeva et al. Photosynth Res 98:105-119, 2008, Plant Physiol Biochem 77:49-59, 2014) were fitted with the PSII model. The simulations show that at high-light conditions the flash generated triplet carotenoid (3)Car(t) population is the main NPQ regulator decaying in the time interval of 6-8 μs. So the SFITFY increase up to the maximum level [Formula: see text]/F 0 (at ~50 μs) depends mainly on the flash energy. Transient electron redistributions on the RC redox cofactors were displayed to explain the SFITFY measured by weak light pulses during the PSII relaxation by electron transfer (ET) steps and coupled proton transfer on both the donor and the acceptor side of the PSII. The contribution of non-radiative charge recombination was taken into account. Analytical expressions for the laser flash, the (3)Car(t) decay and the work of the water-oxidizing complex (WOC) were used to improve the modeled P680(+) reduction by YZ in the state S 1 of the WOC. All parameter values were compared between spinach, A. thaliana leaves and C. pyrenoidosa alga cells and at different laser flash energies. ET from [Formula: see text] slower in alga as compared to leaf samples was elucidated by the dynamics of [Formula: see text] fractions to fit SFITFY data. Low membrane energization after the 10 ns single turnover flash was modeled: the ∆Ψ(t) amplitude (20 mV) is found to be about 5-fold smaller than under the continuous light induction; the time-independent lumen pHL, stroma pHS are fitted close to dark estimates. Depending on the flash energy used at 1

  15. [Research status and prospect on hot water extract of Chlorella: the high value-added bioactive substance from Chlorella].

    PubMed

    Zhuang, Xiuyuan; Huang, Yingming; Zhang, Daojing; Tao, Liming; Li, Yuanguang

    2015-01-01

    Chlorella is nutritious and has been used as a functional food much earlier than the other microalgae. C. pyrenoidosa, the potential microalgae which is currently cultured and developed for the new strategic industry of biofuels production and biological CO2 fixation, is a new resource food announced by the Ministry of Health of the People's Republic of China late 2012. Accumulation of high value-added substances in C. pyrenoidosa during the cultivation for lipid makes it possible to reduce the costs for C. pyrenoidosa-based biofuels production. Among these potential substances, hot water extract of Chlorella (CE), commercially known as "Chlorella growth factor", is the unique one that makes Chlorella more precious than the other algae, and the market price of CE is high. It is believed that CE is effective in growth promotion and immunoregulation. However, there is no systematic analysis on the research status of CE and its bioactivity. The present report summarized recent research progress of CE and its bioactivity. Generally, besides the main effect on immunoregulation and tumor inhibition, CE was efficient in improving metabolic syndrome, scavenging for free radicals, protecting against ultraviolet damage, chelating heavy metals, and protecting liver and bowel. Several major challenges in CE research as well as its prospects were also analysed in the present report.

  16. Effects of Simulated Microgravity on Growth and Metabolism of the Green Alga, Chlorella Pyrenoiosa

    NASA Astrophysics Data System (ADS)

    Kelly, W. A.; Kelly, S. E.; Valluri, J. V.

    2008-06-01

    The Long-duration future habitation of space will require a controlled ecological life support system (CELSS) to simultaneously revitalize atmosphere (liberate oxygen and fix carbon dioxide), purify water (via transpiration), and generate food. The environmental conditions available in the Hydrodynamic Focusing Bioreactor (HFB) provide a novel environment due to the reduction of stress from gravity that influences the growth and protein production of Chlorella pyrenoidosa. Chlorella grown in the HFB conditions exhibited a 3 fold increase in protein production and a 3.5 fold increase in chlorophyll content while averaging a doubling time of 1.47 days.

  17. Mutate Chlorella sp. by nuclear irradiation to fix high concentrations of CO2.

    PubMed

    Cheng, Jun; Huang, Yun; Feng, Jia; Sun, Jing; Zhou, Junhu; Cen, Kefa

    2013-05-01

    To improve biomass productivity and CO2 fixation of microalgae under 15% (v/v) CO2 of flue gas, Chlorella species were mutated by nuclear irradiation and domesticated with high concentrations of CO2. The biomass yield of Chlorella pyrenoidosa mutated using 500 Gy of (60)Co γ irradiation increased by 53.1% (to 1.12 g L(-1)) under air bubbling. The mutants were domesticated with gradually increased high concentrations of CO2 [from 0.038% (v/v) to 15% (v/v)], which increased the biomass yield to 2.41 g L(-1). When light transmission and culture mixing in photo-bioreactors were enhanced at 15% (v/v) CO2, the peak growth rate of the domesticated mutant (named Chlorella PY-ZU1) was increased to 0.68 g L(-1) d(-1). When the ratio of gas flow rate (L min(-1)) to 1L of microalgae culture was 0.011, the peak CO2 fixation rate and the efficiency of Chlorella PY-ZU1 were 1.54 g L(-1) d(-1) and 32.7%, respectively. PMID:23567722

  18. Mutate Chlorella sp. by nuclear irradiation to fix high concentrations of CO2.

    PubMed

    Cheng, Jun; Huang, Yun; Feng, Jia; Sun, Jing; Zhou, Junhu; Cen, Kefa

    2013-05-01

    To improve biomass productivity and CO2 fixation of microalgae under 15% (v/v) CO2 of flue gas, Chlorella species were mutated by nuclear irradiation and domesticated with high concentrations of CO2. The biomass yield of Chlorella pyrenoidosa mutated using 500 Gy of (60)Co γ irradiation increased by 53.1% (to 1.12 g L(-1)) under air bubbling. The mutants were domesticated with gradually increased high concentrations of CO2 [from 0.038% (v/v) to 15% (v/v)], which increased the biomass yield to 2.41 g L(-1). When light transmission and culture mixing in photo-bioreactors were enhanced at 15% (v/v) CO2, the peak growth rate of the domesticated mutant (named Chlorella PY-ZU1) was increased to 0.68 g L(-1) d(-1). When the ratio of gas flow rate (L min(-1)) to 1L of microalgae culture was 0.011, the peak CO2 fixation rate and the efficiency of Chlorella PY-ZU1 were 1.54 g L(-1) d(-1) and 32.7%, respectively.

  19. Catalytic conversion of Chlorella pyrenoidosa to biofuels in supercritical alcohols over zeolites.

    PubMed

    Yang, Le; Ma, Rui; Ma, Zewei; Li, Yongdan

    2016-06-01

    Microalgae have been considered as the feedstock for the third generation biofuels production, given its high lipid content and fast productivity. Herein, a catalytic approach for microalgae liquefaction to biocrude is examined in a temperature range of 250-300°C in methanol and ethanol over zeolites. Higher biocrude yield was achieved in ethanol and at lower temperatures, while better quality biocrude with higher light biocrude ratio and lower average molecular weight (Mw) was favored in methanol and at higher temperatures. Application of zeolites improves the biocrude quality significantly. Among the catalysts, HY shows the strongest acidity and performs the best to produce high quality biocrude. Solid residues have been extensively explored with thermal gravity analysis and elemental analysis. It is reported for the first time that up to 99wt.% of sulfur is deposited in the solid residue at 250°C for both solvents. PMID:26990399

  20. Impacts of CO2 concentration on growth, lipid accumulation, and carbon-concentrating-mechanism-related gene expression in oleaginous Chlorella.

    PubMed

    Fan, Jianhua; Xu, Hui; Luo, Yuanchan; Wan, Minxi; Huang, Jianke; Wang, Weiliang; Li, Yuanguang

    2015-03-01

    Biodiesel production by microalgae with photosynthetic CO2 biofixation is thought to be a feasible way in the field of bioenergy and carbon emission reduction. Knowledge of the carbon-concentrating mechanism plays an important role in improving microalgae carbon fixation efficiency. However, little information is available regarding the dramatic changes of cells suffered upon different environmental factors, such as CO2 concentration. The aim of this study was to investigate the growth, lipid accumulation, carbon fixation rate, and carbon metabolism gene expression under different CO2 concentrations in oleaginous Chlorella. It was found that Chlorella pyrenoidosa grew well under CO2 concentrations ranging from 1 to 20 %. The highest biomass and lipid productivity were 4.3 g/L and 107 mg/L/day under 5 % CO2 condition. Switch from high (5 %) to low (0.03 %, air) CO2 concentration showed significant inhibitory effect on growth and CO2 fixation rate. The amount of the saturated fatty acids was increased obviously along with the transition. Low CO2 concentration (0.03 %) was suitable for the accumulation of saturated fatty acids. Reducing the CO2 concentration could significantly decrease the polyunsaturated degree in fatty acids. Moreover, the carbon-concentrating mechanism-related gene expression revealed that most of them, especially CAH2, LCIB, and HLA3, had remarkable change after 1, 4, and 24 h of the transition, which suggests that Chlorella has similar carbon-concentrating mechanism with Chlamydomonas reinhardtii. The findings of the present study revealed that C. pyrenoidosa is an ideal candidate for mitigating CO2 and biodiesel production and is appropriate as a model for mechanism research of carbon sequestration.

  1. The Chemistry of Sites Binding Rubidium in Chlorella

    PubMed Central

    Cohen, Dan

    1962-01-01

    The chemistry of sites that specifically bind Rb in Chlorella pyrenoidosa has been investigated by changing or modifying specific chemical groups or bonds in the cell and observing changes in binding capacity. Boiling the cells in water or in 70 per cent ethanol did not affect binding capacities of the sites. These results suggest that the integrity of the sites is independent of both hydrogen bonds and hydrophobic bonds, and that the sites, therefore, do not consist of a protein or protein-lipid complex. At 30°C, both 1 M HCL and 0.5 to 1 M NaOH rapidly inactivated 70 per cent of the sites, but over a range of Ph 4.4 to 11.3, there was no effect. The sites are inactivated by strong chelating agents at 0.05 to 0.2 M and by reagents which reduce trivalent iron, and 4 to 10 atoms of iron per site are removed from the cells. Prolonged incubation in iron solutions, but not in solutions of Cu, Mn, or Mg, reversed to a considerable extent inactivation by EDTA. It is suggested that the sites probably bind trivalent iron tightly as chelation bridges which are essential to their structure. These structural bridges are broken when iron is removed by chelating agents or reduction, and are reformed in the presence of iron. Other experimental evidence indicates that amine, sulfhydryl, and carbonyl groups are not structural components of the sites. PMID:19873550

  2. Genomic Foundation of Starch-to-Lipid Switch in Oleaginous Chlorella spp.

    PubMed

    Fan, Jianhua; Ning, Kang; Zeng, Xiaowei; Luo, Yuanchan; Wang, Dongmei; Hu, Jianqiang; Li, Jing; Xu, Hui; Huang, Jianke; Wan, Minxi; Wang, Weiliang; Zhang, Daojing; Shen, Guomin; Run, Conglin; Liao, Junjie; Fang, Lei; Huang, Shi; Jing, Xiaoyan; Su, Xiaoquan; Wang, Anhui; Bai, Lili; Hu, Zanmin; Xu, Jian; Li, Yuanguang

    2015-12-01

    The ability to rapidly switch the intracellular energy storage form from starch to lipids is an advantageous trait for microalgae feedstock. To probe this mechanism, we sequenced the 56.8-Mbp genome of Chlorella pyrenoidosa FACHB-9, an industrial production strain for protein, starch, and lipids. The genome exhibits positive selection and gene family expansion in lipid and carbohydrate metabolism and genes related to cell cycle and stress response. Moreover, 10 lipid metabolism genes might be originated from bacteria via horizontal gene transfer. Transcriptomic dynamics tracked via messenger RNA sequencing over six time points during metabolic switch from starch-rich heterotrophy to lipid-rich photoautotrophy revealed that under heterotrophy, genes most strongly expressed were from the tricarboxylic acid cycle, respiratory chain, oxidative phosphorylation, gluconeogenesis, glyoxylate cycle, and amino acid metabolisms, whereas those most down-regulated were from fatty acid and oxidative pentose phosphate metabolism. The shift from heterotrophy into photoautotrophy highlights up-regulation of genes from carbon fixation, photosynthesis, fatty acid biosynthesis, the oxidative pentose phosphate pathway, and starch catabolism, which resulted in a marked redirection of metabolism, where the primary carbon source of glycine is no longer supplied to cell building blocks by the tricarboxylic acid cycle and gluconeogenesis, whereas carbon skeletons from photosynthesis and starch degradation may be directly channeled into fatty acid and protein biosynthesis. By establishing the first genetic transformation in industrial oleaginous C. pyrenoidosa, we further showed that overexpression of an NAD(H) kinase from Arabidopsis (Arabidopsis thaliana) increased cellular lipid content by 110.4%, yet without reducing growth rate. These findings provide a foundation for exploiting the metabolic switch in microalgae for improved photosynthetic production of food and fuels.

  3. Genomic Foundation of Starch-to-Lipid Switch in Oleaginous Chlorella spp.

    PubMed

    Fan, Jianhua; Ning, Kang; Zeng, Xiaowei; Luo, Yuanchan; Wang, Dongmei; Hu, Jianqiang; Li, Jing; Xu, Hui; Huang, Jianke; Wan, Minxi; Wang, Weiliang; Zhang, Daojing; Shen, Guomin; Run, Conglin; Liao, Junjie; Fang, Lei; Huang, Shi; Jing, Xiaoyan; Su, Xiaoquan; Wang, Anhui; Bai, Lili; Hu, Zanmin; Xu, Jian; Li, Yuanguang

    2015-12-01

    The ability to rapidly switch the intracellular energy storage form from starch to lipids is an advantageous trait for microalgae feedstock. To probe this mechanism, we sequenced the 56.8-Mbp genome of Chlorella pyrenoidosa FACHB-9, an industrial production strain for protein, starch, and lipids. The genome exhibits positive selection and gene family expansion in lipid and carbohydrate metabolism and genes related to cell cycle and stress response. Moreover, 10 lipid metabolism genes might be originated from bacteria via horizontal gene transfer. Transcriptomic dynamics tracked via messenger RNA sequencing over six time points during metabolic switch from starch-rich heterotrophy to lipid-rich photoautotrophy revealed that under heterotrophy, genes most strongly expressed were from the tricarboxylic acid cycle, respiratory chain, oxidative phosphorylation, gluconeogenesis, glyoxylate cycle, and amino acid metabolisms, whereas those most down-regulated were from fatty acid and oxidative pentose phosphate metabolism. The shift from heterotrophy into photoautotrophy highlights up-regulation of genes from carbon fixation, photosynthesis, fatty acid biosynthesis, the oxidative pentose phosphate pathway, and starch catabolism, which resulted in a marked redirection of metabolism, where the primary carbon source of glycine is no longer supplied to cell building blocks by the tricarboxylic acid cycle and gluconeogenesis, whereas carbon skeletons from photosynthesis and starch degradation may be directly channeled into fatty acid and protein biosynthesis. By establishing the first genetic transformation in industrial oleaginous C. pyrenoidosa, we further showed that overexpression of an NAD(H) kinase from Arabidopsis (Arabidopsis thaliana) increased cellular lipid content by 110.4%, yet without reducing growth rate. These findings provide a foundation for exploiting the metabolic switch in microalgae for improved photosynthetic production of food and fuels. PMID:26486592

  4. Chlorella: 125 years of the green survivalist.

    PubMed

    Krienitz, Lothar; Huss, Volker A R; Bock, Christina

    2015-02-01

    Chlorella, the archetype of unicellular green algae, is a high-performance primary producer in aquatic and terrestrial ecosystems. Under the simple spherical morphology of Chlorella, many other 'green balls' unfolded as independent phylogenetic lineages as a result of convergent evolution. By contrast, green algae with strikingly different phenotypes were unmasked as close relatives of Chlorella by modern molecular techniques. Here, we point to the increasing impact of these diverse protists on ecology, evolution, and biotechnology in the light of integrative taxonomy.

  5. Chlorella viruses isolated in China

    SciTech Connect

    Zhang, Y.; Burbank, D.E.; Van Etten, J.L. )

    1988-09-01

    Plaque-forming viruses of the unicellular, eukaryotic, exsymbiotic, Chlorella-like green algae strain NC64A, which are common in the United States, were also present in fresh water collected in the People's Republic of China. Seven of the Chinese viruses were examined in detail and compared with the Chlorella viruses previously isolated in the United States. Like the American viruses, the Chinese viruses were large polyhedra and sensitive to chloroform. They contained numerous structural proteins and large double-stranded DNA genomes of at least 300 kilobase pairs. Each of the DNAs from the Chinese viruses contained 5-methyldeoxycytosine, which varied from 12.6 to 46.7% of the deoxycytosine, and N{sup 6}-methyldeoxyadenosine, which varied from 2.2 to 28.3% of the deoxyadenosine. Four of the Chinese virus DNAs hybridized extensively with {sup 32}P-labeled DNA from the American virus PBCV-1, and three hybridized poorly.

  6. Chlorella viruses isolated in China.

    PubMed Central

    Zhang, Y P; Burbank, D E; Van Etten, J L

    1988-01-01

    Plaque-forming viruses of the unicellular, eucaryotic, exsymbiotic, Chlorella-like green algae strain NC64A, which are common in the United States, were also present in fresh water collected in the People's Republic of China. Seven of the Chinese viruses were examined in detail and compared with the Chlorella viruses previously isolated in the United States. Like the American viruses, the Chinese viruses were large polyhedra and sensitive to chloroform. They contained numerous structural proteins and large double-stranded DNA genomes of at least 300 kilobase pairs. Each of the DNAs from the Chinese viruses contained 5-methyldeoxycytosine, which varied from 12.6 to 46.7% of the deoxycytosine, and N6-methyldeoxyadenosine, which varied from 2.2 to 28.3% of the deoxyadenosine. Four of the Chinese virus DNAs hybridized extensively with DNA from the American virus PBCV-1, and three hybridized poorly. Images PMID:2847652

  7. Effect of light state transitions on the apparent absorption cross section of Photosystem II in Chlorella

    SciTech Connect

    Falkowski, P.G.; Fujita, Yoshihiko

    1986-01-01

    The distribution of excitation energy between photosystems may profoundly affect the quantum yield of photosynthetic oxygen evolution. Excitation energy absorbed by pigment molecules is transferred to reaction centers, where it may potentially drive a photochemical event. To balance the photochemical events in PSII with those in PSI, excitation energy may be transferred between PSII and PSI. This type of energy transfer has been inferred primarily in the steady state quantum yield of oxygen evolution and/or fluorescence with changes in excitation wavelength. These so called ''state transitions'' have been attributed to changes in either the absorption cross section of PSII or ''spillover'' of excitation energy between the two photosystems. We report here on measurements of relative absorption cross sections of PSII under state I and state II light conditions. We simultaneously followed the yields of O/sub 2/ and the change in fluorescence yields, ..delta.. phi, as a function of flash energy using single turnover xenon flashes. Our data suggest that the effective absorption cross section of PSII does not change within +- 10% under physiological conditions in unpoisoned Chlorella pyrenoidosa. 13 refs., 3 figs.

  8. [Effect of blue and red light on the synthesis of ribosomal RNA in Chlorella].

    PubMed

    Steup, M

    1975-10-27

    In autotrophic cultures of Chlorella pyrenoidosa (strain 211-8b) incorporation of tritiated guanosine and uridine into ribosomal RNA is stimulated by light. Blue light of wavelengths around 457 nm is considerably more effective than red light around 679 nm (5-10(-10) Einstein cm-2 sec-1 for both). This effect can be demonstrated for young daughter cells (at the end of the dark period) and for older cells (at the end of the light period). It is shown to depend on a regulation of rRNA-synthesis. The blue light dependent enhancement of incorporation is more pronounced in the cytoplasmic rRNA (25 and 18 s) than in the chloroplast rRNA (23 and 16 s). Blue light of low intensity (1-10(-10) Einstein cm-2 sec-1) has nearly the same effectivity as the fivefold intensity, whereas red light of equal quantum fluxes enhances incorporation only slightly compared with the dark control. The blue light dependent enhancement of rRNA-synthesis continues in the following darkness in contrary to that caused by red light. This enhancement is also found in DCMU-poisened cultures. In contrast to this, is red light in presence of DCMU, incorporation into rRNA is nearly the same as in dark. It is concluded that the regulation of rRNA-synthesis in red light is closely connected to complete photosynthesis, while in blue light an additional regulation takes place independent of photosynthesis.

  9. [Studies on chemical compounds of Chlorella sorokiniana].

    PubMed

    Zhang, Ling; Liu, Ping-huai; Wu, Jiao-na; Yang, Guo-fu; Suo, Yang-yang; Luo, Ning; Chen, Chen

    2015-04-01

    Chemical constituents of Chlorella sorokiniana were isolated and purified by repeated column chromatographies, over silicagel and Sephadex LH-20. Their structures were identified on the basis of physicochemical properties and spectroscopic data analysis. Five compounds were obtained from the petroleum ether extract of Chlorella sorokiniana, and their structures were identified as (22E, 24R)-5alpha, 3beta-epidioxiergosta-6, 22-dien-3beta-ol(1),(24S)-ergosta-7-en-3beta-ol(2), loliolide(3), stigmasta-7,22-dien-3beta,5alpha,6alpha-triol(4), and 3beta-hydroxy-5alpha,6alpha-epoxy-7-megastigmen-9-one(5). The main liposoluble fractions from Chlorella sorokiniana maiuly contain fatty acids, alkyl acids and olefine acids. Components 1-5 were isolated from the genus Chlorella for the first time.

  10. Epigenetic modulation of Chlorella (Chlorella vulgaris) on exposure to polycyclic aromatic hydrocarbons.

    PubMed

    Yang, Mihi; Youn, Je-In; Kim, Seung Joon; Park, Jong Y

    2015-11-01

    DNA methylation in promoter region can be a new chemopreventive marker against polycyclic aromatic hydrocarbons (PAHs). We performed a randomized, double blind and cross-over trial (N=12 healthy females) to evaluate chlorella (Chlorella vulgaris)-induced epigenetic modulation on exposure to PAHs. The subjects consumed 4 tablets of placebo or chlorella supplement (total chlorophyll ≈ 8.3mg/tablet) three times a day before meals for 2 weeks. When the subjects consumed chlorella, status of global hypermethylation (5-methylcytosine) was reduced, compared to placebo (p=0.04). However, DNA methylation at the DNMT1 or NQO1 was not modified by chlorella. We observed the reduced levels of urinary 1-hydroxypyrene (1-OHP), a typical metabolite of PAHs, by chlorella intake (p<0.1) and a positive association between chlorella-induced changes in global hypermethylation and urinary 1-OHP (p<0.01). Therefore, our study suggests chlorella works for PAH-detoxification through the epigenetic modulation, the interference of ADME of PAHs and the interaction of mechanisms.

  11. Biology and Industrial Applications of Chlorella: Advances and Prospects.

    PubMed

    Liu, Jin; Chen, Feng

    2016-01-01

    Chlorella represents a group of eukaryotic green microalgae that has been receiving increasing scientific and commercial interest. It possesses high photosynthetic ability and is capable of growing robustly under mixotrophic and heterotrophic conditions as well. Chlorella has long been considered as a source of protein and is now industrially produced for human food and animal feed. Chlorella is also rich in oil, an ideal feedstock for biofuels. The exploration of biofuel production by Chlorella is underway. Chlorella has the ability to fix carbon dioxide efficiently and to remove nutrients of nitrogen and phosphorous, making it a good candidate for greenhouse gas biomitigation and wastewater bioremediation. In addition, Chlorella shows potential as an alternative expression host for recombinant protein production, though challenges remain to be addressed. Currently, omics analyses of certain Chlorella strains are being performed, which will help to unravel the biological implications of Chlorella and facilitate the future exploration of industrial applications.

  12. Biology and Industrial Applications of Chlorella: Advances and Prospects.

    PubMed

    Liu, Jin; Chen, Feng

    2016-01-01

    Chlorella represents a group of eukaryotic green microalgae that has been receiving increasing scientific and commercial interest. It possesses high photosynthetic ability and is capable of growing robustly under mixotrophic and heterotrophic conditions as well. Chlorella has long been considered as a source of protein and is now industrially produced for human food and animal feed. Chlorella is also rich in oil, an ideal feedstock for biofuels. The exploration of biofuel production by Chlorella is underway. Chlorella has the ability to fix carbon dioxide efficiently and to remove nutrients of nitrogen and phosphorous, making it a good candidate for greenhouse gas biomitigation and wastewater bioremediation. In addition, Chlorella shows potential as an alternative expression host for recombinant protein production, though challenges remain to be addressed. Currently, omics analyses of certain Chlorella strains are being performed, which will help to unravel the biological implications of Chlorella and facilitate the future exploration of industrial applications. PMID:25537445

  13. Substitution of stable isotopes in Chlorella

    NASA Technical Reports Server (NTRS)

    Flaumenhaft, E.; Katz, J. J.; Uphaus, R. A.

    1969-01-01

    Replacement of biologically important isotopes in the alga Chlorella by corresponding heavier stable isotopes produces increasingly greater deviations from the normal cell size and changes the quality and distribution of certain cellular components. The usefulness of isotopically altered organisms increases interest in the study of such permuted organisms.

  14. Effect of aniline on Chlorella vulgaris

    SciTech Connect

    Amman, H.M.; Terry, b.

    1985-08-01

    A direct correlation between concentration of waste effluent, including aniline, released by a dye company into a waterway in Eastern North Carolina, and the rise and fall of populations of Chlorella, was demonstrated previously. The present study establishes threshold concentrations of aniline which affect growth of these algae, but also shows that physiologic parameters within the organism, such as the rate of photosynthesis, were decreased as sub-threshold concentrations of toxicant.

  15. Changes of biomass, lipid content and fatty acids composition under a light-dark cyclic culture of Chlorella pyrenoidosa in response to different temperature.

    PubMed

    Han, Feifei; Wang, Weiliang; Li, Yuanguang; Shen, Guomin; Wan, Minxi; Wang, Jun

    2013-03-01

    For outdoor culture with light-dark cycle, the biomass and lipid losing at night resulted in lowering the biomass and lipid productivity. Previous studies focused on the contents of carbohydrate and protein in response to temperature for production of animal feed and nutritional supplements. In this study, the effects of temperature on the variations of biomass concentration, lipid content and fatty acids composition for production of biofuels were investigated under a light-dark cyclic culture. The results showed that 30 °C was the optimal daytime temperature for achieving high biomass and lipid; raising daytime temperature can lessen night biomass loss and stimulate lipid accumulation. Subsequently, outdoor culture strategy has been improved: keeping culture broth no less than 30 °C during the daytime. Consequently, the net biomass and lipid productivity were increased by 37.8% and 44.9% when compared to the former culture process in the same outdoor climatic conditions.

  16. Genotype versus phenotype variability in Chlorella and Micractinium (Chlorophyta, Trebouxiophyceae).

    PubMed

    Luo, Wei; Pflugmacher, Stephan; Pröschold, Thomas; Walz, Norbert; Krienitz, Lothar

    2006-08-01

    The most recent revision of the genus Chlorella, based on biochemical and SSU rDNA analyses, suggested a reduction to a set of four "true" spherical Chlorella species, while a growing number of morphologically different species such as Micractinium (formerly Micractiniaceae) were found to cluster within the clade of "true"Chlorella. In this study, the generic concept in Chlorellaceae to Chlorella and Micractinium was evaluated by means of combined SSU and ITS-2 rDNA sequence analyses and biotests to induce development of bristles on the cell wall. Molecular phylogenetic analyses of Chlorella and Micractinium strains confirmed their separation into two different genera. In addition, non-homoplasious synapomorphies (NHS) and compensatory base changes (CBC) in the secondary structures of SSU and ITS-2 rDNA sequences were found for both genera using this approach. The Micractinium clade can be differentiated into three different genotypes. Using culture medium of the rotifer Brachionus calyciflorus, phenotypic plasticity in Chlorella and Micractinium was studied. Non-bristled Micractinium cells developed bristles during incubation with Brachionus culture medium, whereas Chlorella did not produce bristles. Grazing experiments with Brachionus showed the rotifer preferred to feed on non-bristled cells. The dominance of colonies versus solitary cells in the Micractinium culture was not correlated with the "Brachionus factor". These results suggest that morphological characteristics like formation of bristles represent phenotypic adaptations to the conditions in the ecosystem.

  17. Structural Organization of DNA in Chlorella Viruses

    PubMed Central

    Wulfmeyer, Timo; Polzer, Christian; Hiepler, Gregor; Hamacher, Kay; Shoeman, Robert; Dunigan, David D.; Van Etten, James L.; Lolicato, Marco; Moroni, Anna; Thiel, Gerhard; Meckel, Tobias

    2012-01-01

    Chlorella viruses have icosahedral capsids with an internal membrane enclosing their large dsDNA genomes and associated proteins. Their genomes are packaged in the particles with a predicted DNA density of ca. 0.2 bp nm−3. Occasionally infection of an algal cell by an individual particle fails and the viral DNA is dynamically ejected from the capsid. This shows that the release of the DNA generates a force, which can aid in the transfer of the genome into the host in a successful infection. Imaging of ejected viral DNA indicates that it is intimately associated with proteins in a periodic fashion. The bulk of the protein particles detected by atomic force microscopy have a size of ∼60 kDa and two proteins (A278L and A282L) of about this size are among 6 basic putative DNA binding proteins found in a proteomic analysis of DNA binding proteins packaged in the virion. A combination of fluorescence images of ejected DNA and a bioinformatics analysis of the DNA reveal periodic patterns in the viral DNA. The periodic distribution of GC rich regions in the genome provides potential binding sites for basic proteins. This DNA/protein aggregation could be responsible for the periodic concentration of fluorescently labeled DNA observed in ejected viral DNA. Collectively the data indicate that the large chlorella viruses have a DNA packaging strategy that differs from bacteriophages; it involves proteins and share similarities to that of chromatin structure in eukaryotes. PMID:22359540

  18. Synthesis of Nitrate Reductase in Chlorella

    PubMed Central

    Funkhouser, Edward A.; Shen, Teh-Chien; Ackermann, Renate

    1980-01-01

    Synthesis of nitrate reductase (EC 1.6.6.1) in Chlorella vulgaris was studied under inducing conditions, i.e. with cells grown on ammonia and then transferred to nitrate medium. Cycloheximide (but not chloramphenicol) completely inhibited synthesis of the enzyme, but only if it was added at the start (i.e. at the time of nitrate addition) of the induction period. Cycloheximide inhibition became less effective as induction by nitrate proceeded. Enzyme from small quantities of culture (1 to 3 milliliters of packed cells) was purified to homogeneity with the aid of blue dextran-Sepharose chromatography. Incorporation of radioactivity from labeled arginine into nitrate reductase was measured in the presence and absence of cycloheximide. Conditions were found under which the inhibitor completely blocked the incorporation of labeled amino acid, but only slightly decreased the increase in nitrate reductase activity. The results indicate that synthesis of nitrate reductase from amino acids proceeds by way of a protein precursor which is inactive enzymically. PMID:16661310

  19. The Respiratory Chain of Chlorella protothecoides

    PubMed Central

    Grant, Neil G.; Hommersand, Max H.

    1974-01-01

    The respiration and cytochrome properties of “glucose-bleached” Chlorella protothecoides Krüger, Indiana strain 25, were studied. This organism, when grown heterotrophically with high glucose and a low organic nitrogen source, has no chlorophyll, little carotenoid, and diminished chloroplast structure—factors which make it suitable for respiration studies. Whole cell endogenous oxygen uptake rates are either stimulated or only slightly inhibited by cyanide, azide, CO, and antimycin. When these inhibitors are used with m-chlorobenz-hydroxamic acid (mCLAM), an inhibitor of higher plant mitochondrial alternate oxidase, O2 uptake is inhibited. There is little effect of mCLAM by itself on the rate of oxygen uptake. The inhibition by CO of O2 uptake in the presence of mCLAM is reversed by light. The cytochrome chain of C. protothecoides consists of cytochromes aa3, b, and c, as revealed by room temperature difference spectra. In common with mitochondria of higher plants, there is a further reduction of cytochrome b with dithionite. In the presence of antimycin, the cytochromes aa3 and c are oxidized and cytochrome b is reduced. Cyanide causes a partial reduction of cytochromes aa3 and c while cytochrome b remains oxidized. This general response is characteristic of higher plant mitochrondria having large amounts of cyanide-resistant respiration. Carbon monoxide spectra reveal one CO-combining pigment. The cytochrome b region differs from that of higher plants in that the typical complex spectrum does not appear at low temperature (−190 C). The concentration of cytochrome aa3 per cell volume was observed during the greening of “glucose-bleached” cells. The concentration of these cytochromes nearly tripled during the 24 hours of the initial stages of greening. PMID:16658836

  20. Secondary symbiosis between Paramecium and Chlorella cells.

    PubMed

    Kodama, Yuuki; Fujishima, Masahiro

    2010-01-01

    Each symbiotic Chlorella species of Paramecium bursaria is enclosed in a perialgal vacuole (PV) membrane derived from the host digestive vacuole (DV) membrane. Algae-free paramecia and symbiotic algae are capable of growing independently and paramecia can be reinfected experimentally by mixing them. This phenomenon provides an excellent model for studying cell-to-cell interaction and the evolution of eukaryotic cells through secondary endosymbiosis between different protists. However, the detailed algal infection process remains unclear. Using pulse labeling of the algae-free paramecia with the isolated symbiotic algae and chase method, we found four necessary cytological events for establishing endosymbiosis. (1) At about 3 min after mixing, some algae show resistance to the host lysosomal enzymes in the DVs, even if the digested ones are present. (2) At about 30 min after mixing, the alga starts to escape from the DVs as the result of the budding of the DV membrane into the cytoplasm. (3) Within 15 min after the escape, the DV membrane enclosing a single green alga differentiates to the PV membrane, which provides protection from lysosomal fusion. (4) The alga localizes at the primary lysosome-less host cell surface by affinity of the PV to unknown structures of the host. At about 24 h after mixing, the alga multiplies by cell division and establishes endosymbiosis. Infection experiments with infection-capable and infection-incapable algae indicate that the infectivity of algae is based on their ability to localize beneath the host surface after escaping from the DVs. This algal infection process differs from known infection processes of other symbiotic or parasitic organisms to their hosts.

  1. Screening and characterization of oleaginous Chlorella strains and exploration of photoautotrophic Chlorella protothecoides for oil production.

    PubMed

    Sun, Zheng; Zhou, Zhi-gang; Gerken, Henri; Chen, Feng; Liu, Jin

    2015-05-01

    The growth and oil production of nine Chlorella strains were comparatively assessed and Chlorellaprotothecoides CS-41 demonstrated the greatest lipid production potential. The effects of different nitrogen forms and concentrations, phosphorus concentrations and light intensities on growth and oil production were studied in laboratory columns. C. protothecoides CS-41 accumulated lipids up to 55% of dry weight, with triacylglycerol and oleic acid being 71% of total lipids and 59% of total fatty acids, respectively. High biomass and lipid productivities were achieved in outdoor panel PBRs, up to 1.25 and 0.59 g L(-1) day(-1), or 44. 1 and 16.1 g m(-2) day(-1), respectively. A two-stage cultivation strategy was proposed to enhance the algal biomass and lipid production. This is the first comprehensive investigation of both indoor and outdoor photoautotrophic C. protothecoides cultures for oil production, and C. protothecoides CS-41 represents a promising biofuel feedstock worthy of further exploration.

  2. Uptake and bioaccumulation of three PCBs by Chlorella fusca

    SciTech Connect

    Wang, K.; Rott, B.; Korte, F.

    1982-01-01

    This paper reports the bioaccumulation of three PCBs (2,4'-dichlorobiphenyl, 2,4,6,2'-tetrachlorobiphenyl and 2,4,6,2',4'-pentachlorobiphenyl) by the green alga Chlorella fusca under various conditions. A probable pattern of the bioconcentration mechanism is suggested. No metabolites were extracted from algae or water 6 days after incubation with PCBs.

  3. Vitreoscilla hemoglobin gene ( vgb) improves lutein production in Chlorella vulgaris

    NASA Astrophysics Data System (ADS)

    Ma, Ruijuan; Lin, Xiangzhi

    2014-03-01

    Vitreoscilla hemoglobin is an oxygen-binding protein that promotes oxygen delivery and reduces oxygen consumption under low oxygen conditions to increase the efficiency of cell respiration and metabolism. In this study, we introduced a Vitreoscilla hemoglobin gene ( vgb) into Chlorella vulgaris by Agrobacterium tumefaciens -mediated transformation (ATMT). PCR analysis confirmed that the vgb gene was successfully integrated into the Chlorella vulgaris genome. Analysis of biomass obtained in shake flasks revealed transformant biomass concentrations as high as 3.28 g/L, which was 38.81% higher than that of the wild-type strain. Lutein content of transformants also increased slightly. Further experiments recovered a maximum lutein yield of 2.91 mg/L from the transformants, which was 36.77% higher than that of the wild-type strain. The above results suggest that integrated expression of the vgb gene may improve cell growth and lutein yield in Chlorella vulgaris, with applications to lutein production from Chlorella during fermentation.

  4. Utilization of papaya waste and oil production by Chlorella protothecoides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Algae derived oils have outstanding potential for use in biodiesel production. Chlorella protothecoides has been shown to accumulate lipid up to 60% of its cellular dry weight with glucose supplementation under heterotrophic growth conditions. To reduce production costs, alternative carbon feedstock...

  5. Chlorella protects against hydrogen peroxide-induced pancreatic β-cell damage.

    PubMed

    Lin, Chia-Yu; Huang, Pei-Jane; Chao, Che-Yi

    2014-12-01

    Oxidative stress has been implicated in the etiology of pancreatic β-cell dysfunction and diabetes. Studies have shown that chlorella could be important in health promotion or disease prevention through its antioxidant capacity. However, whether chlorella has a cytoprotective effect in pancreatic β-cells remains to be elucidated. We investigated the protective effects of chlorella on H2O2-induced oxidative damage in INS-1 (832/13) cells. Chlorella partially restored cell viability after H2O2 toxicity. To further investigate the effects of chlorella on mitochondria function and cellular oxidative stress, we analyzed mitochondria membrane potential, ATP concentrations, and cellular levels of reactive oxygen species (ROS). Chlorella prevented mitochondria disruption and maintained cellular ATP levels after H2O2 toxicity. It also normalized intracellular levels of ROS to that of control in the presence of H2O2. Chlorella protected cells from apoptosis as indicated by less p-Histone and caspase 3 activation. In addition, chlorella not only enhanced glucose-stimulated insulin secretion (GSIS), but also partially restored the reduced GSIS after H2O2 toxicity. Our results suggest that chlorella is effective in amelioration of cellular oxidative stress and destruction, and therefore protects INS-1 (832/13) cells from H2O2-induced apoptosis and increases insulin secretion. Chlorella should be studied for use in the prevention or treatment of diabetes.

  6. Evaluation of Chlorella as a Decorporation Agent to Enhance the Elimination of Radioactive Strontium from Body

    PubMed Central

    Ogawa, Kazuma; Fukuda, Tadahisa; Han, Jaegab; Kitamura, Yoji; Shiba, Kazuhiro; Odani, Akira

    2016-01-01

    Background Release of radionuclides, such as 137Cs and 90Sr, into the atmosphere and the ocean presents an important problem because internal exposure to 137Cs and 90Sr could be very harmful to humans. Chlorella has been reported to be effective in enhancing the excretion of heavy metals; thus, we hypothesized that Chlorella could also enhance the elimination of 137Cs or 90Sr from the body. We evaluated the potential of Chlorella as a decorporation agent in vitro and in vivo, using 85Sr instead of 90Sr. Methods In vitro experiments of adsorption of 137Cs and 85Sr to Chlorella were performed under wide pH conditions. The maximum sorption capacity of Chlorella to strontium was estimated using the Langmuir model. A 85Sr solution was orally administrated to mice pretreated with Chlorella. At 48 h after 85Sr administration, the biodistribution of radioactivity was determined. Results In the in vitro experiments, although 85Sr barely adsorbed to Chlorella at low pH, the 85Sr adsorption ratio to Chlorella increased with increasing pH. The maximum sorption capacity of Chlorella to strontium was 9.06 mg / g. 137Cs barely adsorbed to Chlorella under any pH conditions. In the biodistribution experiments, bone accumulation of radioactivity after 85Sr administration was significantly decreased in the Chlorella pretreatment group compared with the non-treatment control group. Conclusions In conclusion, these results indicated that Chlorella could inhibit the absorption of 90Sr into the blood and enhance the elimination of 90Sr from the body through adsorption in intestine. Further studies are required to elucidate the mechanism and the components of Chlorella needed for adsorption to strontium and could promote the development of more effective decorporation agents. PMID:26828430

  7. Photosynthetic Shutdown in Chlorella NC64A Associated with the Infection Cycle of Paramecium bursaria Chlorella Virus-1.

    PubMed

    Seaton, GGR.; Lee, K.; Rohozinski, J.

    1995-08-01

    The effects of the algal virus Paramecium bursaria Chlorella virus-1 on the photosynthetic physiology of its host, Chlorella NC64A, was studied by observing changes in Chl fluorescence quenching and O2 exchange. Metabolic changes were calibrated against electron microscopic analysis of the morphological changes that occur during the infection cycle. It takes approximately 10 h from attachment of the virus to final lysis of the host cell, so a complete infection cycle can be observed continuously in one experiment. During the early stages of the infection cycle many rapid changes occurred in the host cell's metabolism and these were reflected in changes of photosynthetic and respiratory rates. The dramatic inhibition of photosynthesis in Chlorella NC64A cells by P. bursaria Chlorella virus-1 has facilitated the use of fluorescence quenching as an accurate measure of the first phase of viral infection (attachment and penetration of the host cell) and the extent to which a population of host cells is infected. Effects of temperature and cation requirement of the infection cycle are described. The relevance of our observations to the events observed during viral infection of higher plants is discussed.

  8. Photosynthetic Shutdown in Chlorella NC64A Associated with the Infection Cycle of Paramecium bursaria Chlorella Virus-1.

    PubMed Central

    Seaton, GGR.; Lee, K.; Rohozinski, J.

    1995-01-01

    The effects of the algal virus Paramecium bursaria Chlorella virus-1 on the photosynthetic physiology of its host, Chlorella NC64A, was studied by observing changes in Chl fluorescence quenching and O2 exchange. Metabolic changes were calibrated against electron microscopic analysis of the morphological changes that occur during the infection cycle. It takes approximately 10 h from attachment of the virus to final lysis of the host cell, so a complete infection cycle can be observed continuously in one experiment. During the early stages of the infection cycle many rapid changes occurred in the host cell's metabolism and these were reflected in changes of photosynthetic and respiratory rates. The dramatic inhibition of photosynthesis in Chlorella NC64A cells by P. bursaria Chlorella virus-1 has facilitated the use of fluorescence quenching as an accurate measure of the first phase of viral infection (attachment and penetration of the host cell) and the extent to which a population of host cells is infected. Effects of temperature and cation requirement of the infection cycle are described. The relevance of our observations to the events observed during viral infection of higher plants is discussed. PMID:12228553

  9. Coagulation-flocculation of marine Chlorella sp. for biodiesel production.

    PubMed

    Sanyano, Naruetsawan; Chetpattananondh, Pakamas; Chongkhong, Sininart

    2013-11-01

    Harvesting of marine Chlorella sp. by autoflocculation and flocculation by addition of coagulant with pH adjustment was investigated in this study. Autoflocculation provided low efficiency. Response surface methodology was employed to optimize the coagulant dosage and pH for flocculation. Aluminium sulfate and ferric chloride were investigated coagulants. The empirical models from RSM are in a good agreement with the experimental results. The optimum flocculation was achieved at ferric chloride dosage 143 mg/L, pH 8.1 and settling time 40 min. Biomass concentration also presented the significant effect on harvesting efficiency. Lipid extracted from marine Chlorella sp. cultivated in urea fertilizer medium with hexane as a solvent is suitable to produce biodiesel according to it contains high proportion of saturated fatty acids. The crude lipid should be purified to remove some impurities before making biodiesel. As the free fatty acid content was higher than 1% a two-step biodiesel production is recommended.

  10. Water Permeability of Chlorella Cell Membranes by Nuclear Magnetic Resonance

    PubMed Central

    Stout, Darryl G.; Steponkus, Peter L.; Bustard, Larry D.; Cotts, Robert M.

    1978-01-01

    Measurement by two nuclear magnetic resonance (NMR) techniques of the mean residence time τa of water molecules inside Chlorella vulgaris (Beijerinck) var. “viridis” (Chodot) is reported. The first is the Conlon and Outhred (1972 Biochim Biophys Acta 288: 354-361) technique in which extracellular water is doped with paramagnetic Mn2+ ions. Some complications in application of this technique are identified as being caused by the affinity of Chlorella cell walls for Mn2+ ions which shortens the NMR relaxation times of intra- and extracellular water. The second is based upon observations of effects of diffusion on the spin echo of intra- and extracellular water. Echo attenuation of intracellular water is distinguished from that of extracellular water by the extent to which diffusive motion is restricted. Intracellular water, being restricted to the cell volume, suffers less echo attenuation. From the dependence of echo amplitude upon gradient strength at several values of echo time, the mean residence time of intracellular water can be determined. From the mean residence time of intracellular water, the diffusional water permeability coefficient of the Chlorella membrane is calculated to be 2.1 ± 0.4 × 10−3 cm sec−1. PMID:16660456

  11. Generic concept in Chlorella-related coccoid green algae (Chlorophyta, Trebouxiophyceae).

    PubMed

    Luo, W; Pröschold, T; Bock, C; Krienitz, L

    2010-05-01

    Using a combined set of sequences of SSU and ITS regions of nuclear-encoded ribosomal DNA, the concept of the experimental algal genus Chlorella was evaluated. Conventionally in the genus Chlorella, only coccoid, solitary algae with spherical morphology that do not possess any mucilaginous envelope were included. All Chlorella species reproduce asexually by autospores. However, phylogenetic analyses showed that within the clade of 'true'Chlorella species (Chlorella vulgaris, C. lobophora, and C. sorokiniana), taxa with a mucilaginous envelope and colonial lifeform have also evolved. These algae, formerly designated as Dictyosphaerium, are considered as members of the genus Chlorella. In close relationship to Chlorella, five different genera were supported by the phylogenetic analyses: Micractinium (spherical cells, colonial, with bristles), Didymogenes (ellipsoidal cells, two-celled coenobia, with or without two spines per cell), Actinastrum (ellipsoidal cells within star-shaped coenobia), Meyerella (spherical cells, solitary, without pyrenoids), and Hegewaldia (spherical cells, colonial, with or without bristles, oogamous propagation). Based on the secondary structures of SSU and ITS rDNA sequences, molecular signatures are provided for each genus of the Chlorella clade.

  12. Dietary effects of lutein-fortified chlorella on milk components of Holstein cows.

    PubMed

    Jeon, Jin-Young; Park, Keun-Kyu; Lee, Kyung-Woo; Jang, Seung-Wan; Moon, Byung-Hern; An, Byoung-Ki

    2016-01-01

    This study was conducted to investigate the dietary effect of conventional or lutein-fortified chlorella on milk production and lutein incorporation in milk. Fifteen Holstein cows in mid-lactation were used in a 3 × 3 Latin square design each with a 21-day period. Cows were top-dressed daily with 30 g of conventional or lutein-fortified chlorella for 3 weeks. Cows without chlorella served as the control. The feed intake and milk yield were not affected by dietary treatments. The concentrations of milk protein and solids non-fat in groups fed diets containing both conventional and lutein-fortified chlorella were significantly higher than those of the control group (P < 0.001). There was no significant difference in content of milk fat among groups. The levels of plasma glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, interferon-gamma and interleukin-2 were not influenced by the dietary treatments. Lutein content in milk was significantly increased in groups fed lutein-fortified chlorella as compared with those of conventional chlorella and control, respectively (P < 0.01). These results imply that conventional and lutein-fortified chlorella has positive effects on milk components and the use of lutein-fortified chlorella in a dairy diet is effective in the production of milk enriched with lutein. PMID:27386352

  13. [Research on characteristic of interrelationship between toxic organic compound BPA and Chlorella vulgaris].

    PubMed

    Chen, Shan-Jia; Chen, Xiu-Rong; Yan, Long; Zhao, Jian-Guo; Zhang, Fei; Jiang, Zi-Jian

    2014-04-01

    The effects of different concentrations of bisphenol A (BPA) on Chlorella vulgaris and removal capacity of BPA by Chlorella vulgaris were investigated. Results showed that a low concentration (0-20 mg x L(-1)) of BPA promoted the growth of Chlorella vulgaris, whereas a relative high concentration (20-50 mg x L(-1)) of BPA inhibited the growth of Chlorella vulgaris, and the inhibition effect was positively correlated with the concentration of BPA. Likewise, a high dose of initial BPA (> 20 mg x L(-1)) led to a decline in the content of chlorephyll a. Chlorella vulgaris had BPA removal capacity when initial BPA concentration ranged from 2 mg x L(-1) to 50 mg x L(-1). There was positive correlation between the removal rate of BPA per cell and initial BPA concentration. The removal rate of BPA was the highest when initial BPA was 50 mg x L(-1), which appeared between lag phase and logarithmic phase.

  14. CILIATE-SYMBIONT SPECIFICITY OF FRESHWATER ENDOSYMBIOTIC CHLORELLA (TREBOUXIOPHYCEAE, CHLOROPHYTA)(1).

    PubMed

    Summerer, Monika; Sonntag, Bettina; Sommaruga, Ruben

    2008-02-01

    The nature of Chlorella symbioses in invertebrates and protists has attracted much interest, but the uncertain taxonomy of the algal partner has constrained a deeper ecological understanding of this symbiosis. We sequenced parts of the nuclear 18S rDNA, the internal transcribed spacer (ITS)-1 region, and the chloroplast 16S rDNA of several Chlorella isolated from pelagic ciliate species of different lakes, Paramecium bursaria symbionts, and free-living Chlorella to elucidate phylogenetic relationships of Chlorella-like algae and to assess their host specificity. Sequence analyses resulted in well-resolved phylogenetic trees providing strong statistical support for a homogenous 'zoochlorellae' group of different ciliate species from one lake, but clearly different Chlorella in one of those ciliate species occurring in another lake. The two Chlorella strains isolated from the same ciliate species, but from lakes having a 10-fold difference in underwater UV transparency, also presented a distinct physiological trait, such as the ability to synthesize UV-absorbing substances known as mycosporine-like amino acids (MAAs). Algal symbionts of all P. bursaria strains of different origin resolved in one clade apart from the other ciliate symbionts but split into two distinct lineages, suggesting the existence of a biogeographic pattern. Overall, our results suggest a high degree of species specificity but also hint at the importance of physiological adaptation in symbiotic Chlorella.

  15. Ecological role of algobacterial cenosis links (chlorella - associated microflora or associated bacteria)

    NASA Astrophysics Data System (ADS)

    Pechurkin, N. S.

    The problems of interrelation of microalgae and bacteria in the "autotroph - heterotroph" aquatic biotic cycle are discussed. The cause and mechanisms of algobacterial cenosis formation still have been explained contradictorily. This work views the results of experimental and theoretical study of algobacterial cenosis functioning by the example of microalga Chlorella vulgaris and associated microflora. The representatives of Pseudomonas mainly predominate in the Chlorella microbial complex. The experiment at non-sterile batch cultivation of Chlorella on Tamya medium showed that the biomass of microorganisms increases simultaneously with the increase of microalgal biomass. Microflora of Chlorella can use organic materials evolved by Chlorella after photosynthesis for reproduction. Moreover, microorganisms can use dying cells of Chlorella, i.e. form the "producer - reducer" biocycle. To understand the cenosis-forming role of microalgae the mathematical model of the "autotroph - heterotroph" aquatic biotic cycle was constructed taking into consideration the opportunities for microorganisms of using Chlorella photosynthates, dying cells and contribution of links to the nitrogen cycle. The theoretical investigation showed that the biomass of associated bacteria growing on glucose and detritus exceeds the biomass of bacteria using only microalgal photosynthates, which is comparable with experimental data.

  16. [Culture medium based on biogas slurry and breeding of oil Chlorella].

    PubMed

    Zhao, Feng-Min; Mei, Shuai; Cao, You-Fu; Ding, Jin-Feng; Xu, Jia-Jie; Li, Shu-Jun

    2014-06-01

    The oil chlorella cultivation and biogas slurry treatment were combined. The biogas slurry provided water and nutrient for growing chlorella, at the same time, harmless treatment of biogas slurry was realized. This paper cultivated 4 species of oil chlorella in the mixed medium of biogas slurry and green algae medium (the volume ratios were 1 : 9, 1 : 3, 1 : 1 and 3 : 1, respectively), and compared their oil productivity to select the best oil chlorella species and the optimal culture medium. The results showed that, the combination of medium and chlorella species to reach the highest oil productivity was a volume ratio of 1 : 3 and the chlorella species BJ05, and the oil productivity of chlorella BJ05 was 9.20 mg x (L x d)(-1), higher than that in green algae medium [8.66 mg x (L x d)(-1)]. In mixed medium with a volume ratio of 1:3, the effect of adding different nutrients into the green algae medium on the oil productivity was examined, and the results showed that, sodium carbonate and citric acid had no negative effect on the oil productivity of chlorella BJ05. in the absence of sodium carbonate and citric acid, the oil productivity of chlorella BJ05 was 9.36 mg x (L x d)(-1), and the removal of COD (chemical oxygen demand), total nitrogen, total phosphorus and ammonia nitrogen rates were 59%, 75%, 61% and 100%, respectively. Deficiency in other nutrients had negative effect on the oil productivity. Therefore, the culture medium was further optimized to the mixed medium of biogas slurry and green algae medium with a volume ratio of 1 : 3 and without addition of sodium carbonate and citric acid.

  17. The inactivation of Chlorella spp. with dielectric barrier discharge in gas-liquid mixture

    NASA Astrophysics Data System (ADS)

    Song, Dan; Sun, Bing; Zhu, Xiaomei; Yan, Zhiyu; Liu, Hui; Liu, Yongjun

    2013-03-01

    The inactivation of Chlorella spp. with high voltage and frequency pulsed dielectric barrier discharge in hybrid gas-liquid reactor with a suspension electrode was studied experimentally. In the hybrid gas-liquid reactor, a steel plate was used as high voltage electrode while a quartz plate as a dielectric layer, another steel plate placing in the aqueous solution worked as a whole ground electrode. A suspension electrode is installed near the surface of solution between high voltage and ground electrode to make the dielectric barrier discharge uniform and stable, the discharge gap was between the quartz plate and the surface of the water. The effect of peak voltage, treatment time, the initial concentration of Chlorella spp. and conductivity of solution on the inactivation rate of Chlorella spp. was investigated, and the inactivation mechanism of Chlorella spp. preliminarily was studied. Utilizing this system inactivation of Chlorella spp., the inactivation rate increased with increasing of peak voltage, treatment time and electric conductivity. It was found that the inactivation rate of Chlorella spp. arrived at 100% when the initial concentration was 4 × 106 cells mL-1, and the optimum operation condition required a peak voltage of 20 kV, a treatment time of 10 min and a frequency of 7 kHz. Though the increasing of initial concentration of the Chlorella spp. contributed to the addition of interaction probability between the Chlorella spp. and O3, H2O2, high-energy electrons, UV radiation and other active substances, the total inactivation number raise, but the inactivation rate of the Chlorella spp. decreased.

  18. Chlorella suppresses methylmercury transfer to the fetus in pregnant mice.

    PubMed

    Uchikawa, Takuya; Maruyama, Isao; Kumamoto, Shoichiro; Ando, Yotaro; Yasutake, Akira

    2011-10-01

    To investigate the effects of chlorella on methylmercury (MeHg) transfer to the fetus during pregnancy, female C57BL/6N mice (aged 10 weeks) were housed for 7 to 8 weeks, from 4 weeks before mating to birth, with diets containing 0% or 10% chlorella powder (CP) and MeHg-containing drinking water (2 µg Hg/ml). The consumption volume of the MeHg-containing water was limited to 15 ml/mouse/week throughout the experiment. Distilled water and a basal diet (0% CP) was given to control mice. Except for the mating period, during the 5(th) week, mice were housed individually until parturition. Two neonates were randomly selected from each mother mouse within 24 hr after parturition for Hg analysis of the blood, brain, liver, and kidneys. Mother mice were sacrificed on the same day as neonates to obtain tissue samples for Hg analysis. The blood and brain Hg levels of both neonates and mothers in the CP diet group were significantly lower than those in the basal diet group. Although the hepatic and renal Hg levels were not significant in mothers between the two dietary groups, in neonates, the CP diet group showed significantly lower Hg levels in these tissues than the basal diet group. The results obtained here revealed that continuous CP intake suppressed MeHg transfer to the fetus, in addition to effective suppressing MeHg accumulation in brains of the mothers.

  19. Screening of Natural Waters for Viruses Which Infect Chlorella Cells

    PubMed Central

    Yamada, Takashi; Higashiyama, Takanobu; Fukuda, Takao

    1991-01-01

    By using a plaque assay with the unicellular green alga Chlorella sp. strain NC64A as a host, viruses were screened from natural pond waters collected in Kyoto and Higashi-Hiroshima, Japan. From some samples tested, two kinds of plaques, large (φ = 6 to 10 mm) and small (φ = 2 to 3 mm), were detected with various frequencies. The frequency of plaques in each of the water sources was seasonal; generally, it reached a peak value (8,000 PFU/ml) in May and gradually decreased to the limit of detection (<1) in November before increasing again in early spring. Electron microscopy revealed that the purified and negatively stained viruses were very large (125 to 200 nm) icosahedral particles. The genome isolated from these particles was always a linear double-stranded DNA of 340 to 370 kbp. Electrophoresis patterns of the DNA fragments produced by digestion with restriction enzymes differed considerably from plaque to plaque, even for plaques from the same water source. However, Southern hybridization showed strong homology among all of the virus DNAs tested, indicating relatedness of those viruses. A possible use of the Chlorella virus assay system to monitor the natural population of algal cells and water quality is discussed. Images PMID:16348596

  20. Electrophoretic karyotyping and chromosomal gene mapping of Chlorella.

    PubMed Central

    Higashiyama, T; Yamada, T

    1991-01-01

    Molecular karyotypes for six strains of four Chlorella species were obtained by using an alternating-field gel electrophoresis system which employs contour-clamped homogenous electric fields (CHEF). The number and migration pattern of the chromosomal DNA molecules varied greatly from strain to strain: for example, nine separated chromosomes of C. ellipsoidea C87 ranged from 2.5 to 6.5 megabase pairs (mbp) in size, whereas 16 chromosomes of C. vulgaris C169 were from 980 kilobase pairs (kbp) to 4.0 mbp. Depending on the chromosome migration patterns, the six strains were classified into two major chromosome-length polymorphism groups. Using hybridization techniques, the genes for alpha-tublin, chlorophyll-a, b-binding proteins, ribosomal RNAs, and the small subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) were mapped on the separated chromosomes of C. vulgaris C169. Since Chlorella chromosomes are small enough to separate and isolate individually by CHEF gel electrophoresis under ordinary conditions, they should serve as excellent materials to study the fundamental molecular structure of plant-type chromosomes. Images PMID:1956777

  1. Studies on uroporphyrinogen decarboxylase from Chlorella kessleri (Trebouxiophyceae, Chlorophyta).

    PubMed

    Juárez, Angela B; Aldonatti, Carmen; Vigna, María S; Ríos de Molina, María Del C

    2007-02-01

    Uroporphyrinogen decarboxylase (UroD) (EC 4.1.1.37) is an enzyme from the tetrapyrrole biosynthetic pathway, in which chlorophyll is the main final product in algae. This is the first time that a study on UroD activity has been performed in a green alga (Chlorella). We isolated and partially purified the enzyme from a Chlorella kessleri (Trebouxiophyceae, Chlorophyta) strain (Copahue, Neuquén, Argentina), and describe for the first time some of its properties. In C. kessleri, the decarboxylation of uroporphyrinogen III occurs in two stages, via 7 COOH and then 6 and 5 COOH intermediates, with the decarboxylation of the 7 COOH compound being the rate-limiting step for the reaction. Cultures in the exponential growth phase showed the highest specific activity values. The most suitable conditions to measure UroD activity in C. kessleri were as follows: 0.23-0.3 mg protein/mL, approximately 6-8 micromol/L uroporphyrinogen III, and 20 min incubation time. Gel filtration chromatography and Western blot assays indicated that UroD from C. kessleri is a dimer of approximately 90 kDa formed by species of lower molecular mass, which conserves enzymatic activity.

  2. Stability and loading properties of curcumin encapsulated in Chlorella vulgaris.

    PubMed

    Jafari, Yaser; Sabahi, Hossein; Rahaie, Mahdi

    2016-11-15

    Curcumin (Cur), a polyphenols with pharmacological function, was successfully encapsulated in algae (Alg) cell (Chlorella vulgaris) as confirmed by fluorescence microscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform-infrared spectroscopy (FT-IR). Fluorescence micrographs, TGA, DSC and FTIR spectra suggested the hypothesis inclusion Cur in Nano-empty spaces inside cell wall of Alg. The TGA analysis showed that the thermal stability of Alg and Cur at algae/curcumin complex was 3.8% and 33% higher than their free forms at 0-300°C and 300-600°C ranges, respectively. After encapsulation in Alg cells, the photostability of Cur was enhanced by about 2.5-fold. Adsorption isotherm of Cur into Alg was fitted with the Freundlich isotherm. The microcapsules were loaded with Cur up to about 55% w/w which is much higher than other reported bio-carriers. In conclusion, the data proved that Chlorella vulgaris cell can be used as a new stable carrier for Cur. PMID:27283686

  3. Evidence for a plasma-membrane-bound nitrate reductase involved in nitrate uptake of Chlorella sorokiniana

    NASA Technical Reports Server (NTRS)

    Tischner, R.; Ward, M. R.; Huffaker, R. C.

    1989-01-01

    Anti-nitrate-reductase (NR) immunoglobulin-G (IgG) fragments inhibited nitrate uptake into Chlorella cells but had no affect on nitrate uptake. Intact anti-NR serum and preimmune IgG fragments had no affect on nitrate uptake. Membrane-associated NR was detected in plasma-membrane (PM) fractions isolated by aqueous two-phase partitioning. The PM-associated NR was not removed by sonicating PM vesicles in 500 mM NaCl and 1 mM ethylenediaminetetraacetic acid and represented up to 0.8% of the total Chlorella NR activity. The PM NR was solubilized by Triton X-100 and inactivated by Chlorella NR antiserum. Plasma-membrane NR was present in ammonium-grown Chlorella cells that completely lacked soluble NR activity. The subunit sizes of the PM and soluble NRs were 60 and 95 kDa, respectively, as determined by sodium-dodecyl-sulfate electrophoresis and western blotting.

  4. Optical Manipulation of Symbiotic Chlorella in Paramecium Bursaria Using a Fiber Axicon Microlens

    NASA Astrophysics Data System (ADS)

    Taguchi, K.; Hirota, S.; Nakayama, H.; Kunugihara, D.; Mihara, Y.

    2012-03-01

    In this paper, chemically etched axicon fiber was proposed for laser trapping of symbiotic chlorella from paramecium bursaria. We fabricated axicon micro lenses on a single-mode bare optical fiber by selective chemical etching technique. The laser beam from fiber axicon microlens was strongly focused and optical forces were sufficient to move a symbiotic chlorella. From experimental results, it was found that our proposed fiber axicon microlens was a promising tool for cell trapping without physical contact.

  5. Preventive effects of Chlorella on cognitive decline in age-dependent dementia model mice.

    PubMed

    Nakashima, Yuya; Ohsawa, Ikuroh; Konishi, Fumiko; Hasegawa, Takashi; Kumamoto, Shoichiro; Suzuki, Yoshihiko; Ohta, Shigeo

    2009-10-30

    Oxidative stress is one of the major causes of age-dependent memory loss and cognitive decline. Cytotoxic aldehydes are derived from lipid peroxides and their accumulation may be responsible for age-dependent neurodegeneration, including Alzheimer's disease. Since aldehyde dehydrogenases detoxify such aldehydes, we constructed transgenic mice with mitochondrial aldehyde dehydrogenase 2 (ALDH2) activity deficiency (DAL101 mice) as an age-dependent dementia model. This model animal is age-dependently progressed by persistent oxidative stress, and thus enables us to investigate foods that prevent dementia. Since Chlorella, a kind of alga, exhibits various anti-oxidative effects, we investigated whether Chlorella has the potential to prevent age-dependent cognitive impairment. We fed Chlorella to DAL101 mice and investigated its effects on oxidative stress and the progression of cognitive decline using the Morris water-maze and object recognition tests. The diet with Chlorella tended to reduce oxidative stress and significantly prevented the decline of cognitive ability, as shown by both methods. Moreover, consumption of Chlorella decreased the number of activated astrocytes in the DAL101 brain. These findings suggest that the prolonged consumption of Chlorella has the potential to prevent the progression of cognitive impairment.

  6. Effect of maternal Chlorella supplementation on carotenoid concentration in breast milk at early lactation.

    PubMed

    Nagayama, Junya; Noda, Kiyoshi; Uchikawa, Takuya; Maruyama, Isao; Shimomura, Hiroshi; Miyahara, Michiyoshi

    2014-08-01

    Breast milk carotenoids provide neonates with a source of vitamin A and potentially, oxidative stress protection and other health benefits. Chlorella, which has high levels of carotenoids such as lutein, zeaxanthin and β-carotene, is an effective dietary source of carotenoids for humans. In this study, the effect of maternal supplementation with Chlorella on carotenoid levels in breast milk at early lactation was investigated. Ten healthy, pregnant women received 6 g of Chlorella daily from gestational week 16-20 until the day of delivery (Chlorella group); ten others did not (control group). Among the carotenoids detected in breast milk, lutein, zeaxanthin and β-carotene concentrations in the Chlorella group were 2.6-fold (p = 0.001), 2.7-fold (p = 0.001) and 1.7-fold (p = 0.049) higher, respectively, than those in the control group. Our study shows that Chlorella intake during pregnancy is effective in improving the carotenoid status of breast milk at early lactation.

  7. Association of Paramecium bursaria Chlorella viruses with Paramecium bursaria cells: ultrastructural studies.

    PubMed

    Yashchenko, Varvara V; Gavrilova, Olga V; Rautian, Maria S; Jakobsen, Kjetill S

    2012-05-01

    Paramecium bursaria Chlorella viruses were observed by applying transmission electron microscopy in the native symbiotic system Paramecium bursaria (Ciliophora, Oligohymenophorea) and the green algae Chlorella (Chlorellaceae, Trebouxiophyceae). Virus particles were abundant and localized in the ciliary pits of the cortex and in the buccal cavity of P. bursaria. This was shown for two types of the symbiotic systems associated with two types of Chlorella viruses - Pbi or NC64A. A novel quantitative stereological approach was applied to test whether virus particles were distributed randomly on the Paramecium surface or preferentially occupied certain zones. The ability of the virus to form an association with the ciliate was investigated experimentally; virus particles were mixed with P. bursaria or with symbiont-free species P. caudatum. Our results confirmed that in the freshwater ecosystems two types of P. bursaria -Chlorella symbiotic systems exist, those without Chlorella viruses and those associated with a large amount of the viruses. The fate of Chlorella virus particles at the Paramecium surface was determined based on obtained statistical data and taking into account ciliate feeding currents and cortical reorganization during cell division. A life cycle of the viruses in the complete symbiotic system is proposed.

  8. Widespread green algae Chlorella and Stichococcus exhibit polar-temperate and tropical-temperate biogeography.

    PubMed

    Hodač, Ladislav; Hallmann, Christine; Spitzer, Karolin; Elster, Josef; Faßhauer, Fabian; Brinkmann, Nicole; Lepka, Daniela; Diwan, Vaibhav; Friedl, Thomas

    2016-08-01

    Chlorella and Stichococcus are morphologically simple airborne microalgae, omnipresent in terrestrial and aquatic habitats. The minute cell size and resistance against environmental stress facilitate their long-distance dispersal. However, the actual distribution of Chlorella- and Stichococcus-like species has so far been inferred only from ambiguous morphology-based evidence. Here we contribute a phylogenetic analysis of an expanded SSU and ITS2 rDNA sequence dataset representing Chlorella- and Stichococcus-like species from terrestrial habitats of polar, temperate and tropical regions. We aim to uncover biogeographical patterns at low taxonomic levels. We found that psychrotolerant strains of Chlorella and Stichococcus are closely related with strains originating from the temperate zone. Species closely related to Chlorella vulgaris and Muriella terrestris, and recovered from extreme terrestrial environments of polar regions and hot deserts, are particularly widespread. Stichococcus strains from the temperate zone, with their closest relatives in the tropics, differ from strains with the closest relatives being from the polar regions. Our data suggest that terrestrial Chlorella and Stichococcus might be capable of intercontinental dispersal; however, their actual distributions exhibit biogeographical patterns. PMID:27279416

  9. Widespread green algae Chlorella and Stichococcus exhibit polar-temperate and tropical-temperate biogeography.

    PubMed

    Hodač, Ladislav; Hallmann, Christine; Spitzer, Karolin; Elster, Josef; Faßhauer, Fabian; Brinkmann, Nicole; Lepka, Daniela; Diwan, Vaibhav; Friedl, Thomas

    2016-08-01

    Chlorella and Stichococcus are morphologically simple airborne microalgae, omnipresent in terrestrial and aquatic habitats. The minute cell size and resistance against environmental stress facilitate their long-distance dispersal. However, the actual distribution of Chlorella- and Stichococcus-like species has so far been inferred only from ambiguous morphology-based evidence. Here we contribute a phylogenetic analysis of an expanded SSU and ITS2 rDNA sequence dataset representing Chlorella- and Stichococcus-like species from terrestrial habitats of polar, temperate and tropical regions. We aim to uncover biogeographical patterns at low taxonomic levels. We found that psychrotolerant strains of Chlorella and Stichococcus are closely related with strains originating from the temperate zone. Species closely related to Chlorella vulgaris and Muriella terrestris, and recovered from extreme terrestrial environments of polar regions and hot deserts, are particularly widespread. Stichococcus strains from the temperate zone, with their closest relatives in the tropics, differ from strains with the closest relatives being from the polar regions. Our data suggest that terrestrial Chlorella and Stichococcus might be capable of intercontinental dispersal; however, their actual distributions exhibit biogeographical patterns.

  10. Selection of microalgae for high CO2 fixation efficiency and lipid accumulation from ten Chlorella strains using municipal wastewater.

    PubMed

    Hu, Xia; Zhou, Jiti; Liu, Guangfei; Gui, Bing

    2016-08-01

    As significant differences in cellular physiology, metabolic potential and genetics occur among strains with morphological similarity, the screening of appropriate microalgae species for effective CO2 fixation and biodiesel production is extremely critical. In this study, ten strains of Chlorella were cultivated in municipal wastewater influent (MWI) and their tolerance for MWI, CO2 fixation efficiency and lipid productivity were assessed. The results showed that the biomass concentrations of four strains (Chlorella vulgaris, Chlorella 64.01, Chlorella regularis var. minima and Chlorella sp.) were significantly higher than other strains. When the cultivation systems were aerated with 10% CO2, Chlorella sp. showed the highest CO2 fixation efficiency (35.51%), while the highest lipid accumulation (58.48%) was observed with C. vulgaris. Scanning electron microscopy images revealed that the cells of both Chlorella sp. and C. vulgaris kept their normal morphologies after 15day batch culture. These findings indicated that Chlorella sp. and C. vulgaris have fairly good tolerance for MWI, and moreover, Chlorella sp. was appropriate for CO2 fixation while C. vulgaris represented the highest potential for producing biodiesel.

  11. Selection of microalgae for high CO2 fixation efficiency and lipid accumulation from ten Chlorella strains using municipal wastewater.

    PubMed

    Hu, Xia; Zhou, Jiti; Liu, Guangfei; Gui, Bing

    2016-08-01

    As significant differences in cellular physiology, metabolic potential and genetics occur among strains with morphological similarity, the screening of appropriate microalgae species for effective CO2 fixation and biodiesel production is extremely critical. In this study, ten strains of Chlorella were cultivated in municipal wastewater influent (MWI) and their tolerance for MWI, CO2 fixation efficiency and lipid productivity were assessed. The results showed that the biomass concentrations of four strains (Chlorella vulgaris, Chlorella 64.01, Chlorella regularis var. minima and Chlorella sp.) were significantly higher than other strains. When the cultivation systems were aerated with 10% CO2, Chlorella sp. showed the highest CO2 fixation efficiency (35.51%), while the highest lipid accumulation (58.48%) was observed with C. vulgaris. Scanning electron microscopy images revealed that the cells of both Chlorella sp. and C. vulgaris kept their normal morphologies after 15day batch culture. These findings indicated that Chlorella sp. and C. vulgaris have fairly good tolerance for MWI, and moreover, Chlorella sp. was appropriate for CO2 fixation while C. vulgaris represented the highest potential for producing biodiesel. PMID:27521939

  12. An experimental test of the symbiosis specificity between the ciliate Paramecium bursaria and strains of the unicellular green alga Chlorella.

    PubMed

    Summerer, Monika; Sonntag, Bettina; Sommaruga, Ruben

    2007-08-01

    The ciliate Paramecium bursaria living in mutualistic relationship with the unicellular green alga Chlorella is known to be easily infected by various potential symbionts/parasites such as bacteria, yeasts and other algae. Permanent symbiosis, however, seems to be restricted to Chlorella taxa. To test the specificity of this association, we designed infection experiments with two aposymbiotic P. bursaria strains and Chlorella symbionts isolated from four Paramecium strains, seven other ciliate hosts and two Hydra strains, as well as three free-living Chlorella species. Paramecium bursaria established stable symbioses with all tested Chlorella symbionts of ciliates, but never with symbiotic Chlorella of Hydra viridissima or with free-living Chlorella. Furthermore, we tested the infection specificity of P. bursaria with a 1:1:1 mixture of three compatible Chlorella strains, including the native symbiont, and then identified the strain of the newly established symbiosis by sequencing the internal transcribed spacer region 1 of the 18S rRNA gene. The results indicated that P. bursaria established symbiosis with its native symbiont. We conclude that despite clear preferences for their native Chlorella, the host-symbiont relationship in P. bursaria is flexible.

  13. Polyphosphate during the Regreening of Chlorella vulgaris under Nitrogen Deficiency

    PubMed Central

    Chu, Fei-Fei; Shen, Xiao-Fei; Lam, Paul K. S.; Zeng, Raymond J.

    2015-01-01

    Polyphosphate (Poly-P) accumulation has been reported in Chlorella vulgaris under nitrogen deficiency conditions with sufficient P supply, and the process has been demonstrated to have great impact on lipid productivity. In this article, the utilization of polyphosphates and the regreening process under N resupplying conditions, especially for lipid production reviving, were investigated. This regreening process was completed within approximately 3–5 days. Polyphosphates were first degraded within 3 days in the regreening process, with and without an external P supply, and the degradation preceded the assimilation of phosphate in the media with an external P offering. Nitrate assimilation was markedly influenced by the starvation of P after polyphosphates were exhausted in the medium without external phosphates, and then the reviving process of biomass and lipid production was strictly impeded. It is, thus, reasonable to assume that simultaneous provision of external N and P is essential for overall biodiesel production revival during the regreening process. PMID:26426008

  14. Enhancing methane production of Chlorella vulgaris via thermochemical pretreatments.

    PubMed

    Mendez, Lara; Mahdy, Ahmed; Timmers, Rudolphus A; Ballesteros, Mercedes; González-Fernández, Cristina

    2013-12-01

    To enhance the anaerobic digestion of Chlorella vulgaris, thermochemical pretreatments were conducted. All pretreatments markedly improved solubilisation of carbohydrates. Thermal treatments and thermal treatments combined with alkali resulted in 5-fold increase of soluble carbohydrates while thermal treatment with acid addition enhanced by 7-fold. On the other hand, proteins were only solubilized with thermo-alkaline conditions applied. Likewise, all the pretreatments tested improved methane production. Highest anaerobic digestion was accomplished by thermal treatment at 120°C for 40 min without any chemical addition. As a matter of fact, hydrolysis constant rate was doubled under this condition. According to the energetic analysis, energy input was higher than the extra energy gain at the solid concentration employed. Nevertheless, higher biomass organic load pretreatment may be an option to achieve positive energetic balances. PMID:24096280

  15. Recycling of food waste as nutrients in Chlorella vulgaris cultivation.

    PubMed

    Lau, Kin Yan; Pleissner, Daniel; Lin, Carol Sze Ki

    2014-10-01

    Heterotrophic cultivation of Chlorella vulgaris was investigated in food waste hydrolysate. The highest exponential growth rate in terms of biomass of 0.8day(-1) was obtained in a hydrolysate consisting of 17.9gL(-1) glucose, 0.1gL(-1) free amino nitrogen, 0.3gL(-1) phosphate and 4.8mgL(-1) nitrate, while the growth rate was reduced in higher concentrated hydrolysates. C. vulgaris utilized the nutrients recovered from food waste for the formation of biomass and 0.9g biomass was produced per gram glucose consumed. The microalgal biomass produced in nutrient sufficient batch cultures consisted of around 400mgg(-1) carbohydrates, 200mgg(-1) proteins and 200mgg(-1) lipids. The conversion of nutrients derived from food waste and the balanced biomass composition make C. vulgaris a promising strain for the recycling of food waste in food, feed and fuel productions.

  16. Bioaccessibility of carotenoids from Chlorella vulgaris and Chlamydomonas reinhardtii.

    PubMed

    Gille, Andrea; Trautmann, Andreas; Posten, Clemens; Briviba, Karlis

    2015-08-01

    Microalgae can contribute to a balanced diet because of their composition. Beside numerous essential nutrients, carotenoids are in the focus for food applications. The bioavailability of carotenoids from photoautotrophic-cultivated Chlorella vulgaris (C. vulgaris) and Chlamydomonas reinhardtii (C. reinhardtii) was compared. An in vitro digestion model was used to investigate carotenoid bioaccessibility. Furthermore, the effect of sonication on bioaccessibility was assessed. Lutein was the main carotenoid in both species. C. reinhardtii showed higher amounts of lutein and β-carotene than C. vulgaris. In contrast to C. reinhardtii, no β-carotene and only 7% of lutein were bioaccessible in nonsonicated C. vulgaris. Sonication increased the bioaccessibility of carotenoids from C. vulgaris to a level comparable with C. reinhardtii (β-carotene: ≥ 10%; lutein: ≥ 15%). Thus, C. reinhardtii represents a good carotenoid source for potential use in foods without processing, while the application of processing methods, like sonication, is necessary for C. vulgaris. PMID:27146695

  17. Physiological and biochemical responses of Chlorella vulgaris to Congo red.

    PubMed

    Hernández-Zamora, Miriam; Perales-Vela, Hugo Virgilio; Flores-Ortíz, César Mateo; Cañizares-Villanueva, Rosa Olivia

    2014-10-01

    Extensive use of synthetic dyes in many industrial applications releases large volumes of wastewater. Wastewaters from dying industries are considered hazardous and require careful treatment prior to discharge into receiving water bodies. Dyes can affect photosynthetic activities of aquatic flora and decrease dissolved oxygen in water. The aim of this study was to evaluate the effect of Congo red on growth and metabolic activity of Chlorella vulgaris after 96h exposure. Exposure of the microalga to Congo red reduced growth rate, photosynthesis and respiration. Analysis of chlorophyll a fluorescence emission showed that the donor side of photosystem II was affected at high concentrations of Congo red. The quantum yield for electron transport (φEo), the electron transport rate (ETR) and the performance index (PI) also decreased. The reduction in the ability to absorb and use the quantum energy increased non-photochemical (NPQ) mechanisms for thermal dissipation. Overall, Congo red affects growth and metabolic activity in photosynthetic organisms in aquatic environments.

  18. Polyphosphate during the Regreening of Chlorella vulgaris under Nitrogen Deficiency.

    PubMed

    Chu, Fei-Fei; Shen, Xiao-Fei; Lam, Paul K S; Zeng, Raymond J

    2015-01-01

    Polyphosphate (Poly-P) accumulation has been reported in Chlorella vulgaris under nitrogen deficiency conditions with sufficient P supply, and the process has been demonstrated to have great impact on lipid productivity. In this article, the utilization of polyphosphates and the regreening process under N resupplying conditions, especially for lipid production reviving, were investigated. This regreening process was completed within approximately 3-5 days. Polyphosphates were first degraded within 3 days in the regreening process, with and without an external P supply, and the degradation preceded the assimilation of phosphate in the media with an external P offering. Nitrate assimilation was markedly influenced by the starvation of P after polyphosphates were exhausted in the medium without external phosphates, and then the reviving process of biomass and lipid production was strictly impeded. It is, thus, reasonable to assume that simultaneous provision of external N and P is essential for overall biodiesel production revival during the regreening process. PMID:26426008

  19. Enhancing methane production of Chlorella vulgaris via thermochemical pretreatments.

    PubMed

    Mendez, Lara; Mahdy, Ahmed; Timmers, Rudolphus A; Ballesteros, Mercedes; González-Fernández, Cristina

    2013-12-01

    To enhance the anaerobic digestion of Chlorella vulgaris, thermochemical pretreatments were conducted. All pretreatments markedly improved solubilisation of carbohydrates. Thermal treatments and thermal treatments combined with alkali resulted in 5-fold increase of soluble carbohydrates while thermal treatment with acid addition enhanced by 7-fold. On the other hand, proteins were only solubilized with thermo-alkaline conditions applied. Likewise, all the pretreatments tested improved methane production. Highest anaerobic digestion was accomplished by thermal treatment at 120°C for 40 min without any chemical addition. As a matter of fact, hydrolysis constant rate was doubled under this condition. According to the energetic analysis, energy input was higher than the extra energy gain at the solid concentration employed. Nevertheless, higher biomass organic load pretreatment may be an option to achieve positive energetic balances.

  20. Thermogravimetric analysis of the gasification of microalgae Chlorella vulgaris.

    PubMed

    Figueira, Camila Emilia; Moreira, Paulo Firmino; Giudici, Reinaldo

    2015-12-01

    The gasification of microalgae Chlorella vulgaris under an atmosphere of argon and water vapor was investigated by thermogravimetric analysis. The data were interpreted by using conventional isoconversional methods and also by the independent parallel reaction (IPR) model, in which the degradation is considered to happen individually to each pseudo-component of biomass (lipid, carbohydrate and protein). The IPR model allows obtaining the kinetic parameters of the degradation reaction of each component. Three main stages were observed during the gasification process and the differential thermogravimetric curve was satisfactorily fitted by the IPR model considering three pseudocomponents. The comparison of the activation energy values obtained by the methods and those found in the literature for other microalgae was satisfactory. Quantification of reaction products was performed using online gas chromatography. The major products detected were H2, CO and CH4, indicating the potential for producing fuel gas and syngas from microalgae.

  1. Thermogravimetric analysis of the gasification of microalgae Chlorella vulgaris.

    PubMed

    Figueira, Camila Emilia; Moreira, Paulo Firmino; Giudici, Reinaldo

    2015-12-01

    The gasification of microalgae Chlorella vulgaris under an atmosphere of argon and water vapor was investigated by thermogravimetric analysis. The data were interpreted by using conventional isoconversional methods and also by the independent parallel reaction (IPR) model, in which the degradation is considered to happen individually to each pseudo-component of biomass (lipid, carbohydrate and protein). The IPR model allows obtaining the kinetic parameters of the degradation reaction of each component. Three main stages were observed during the gasification process and the differential thermogravimetric curve was satisfactorily fitted by the IPR model considering three pseudocomponents. The comparison of the activation energy values obtained by the methods and those found in the literature for other microalgae was satisfactory. Quantification of reaction products was performed using online gas chromatography. The major products detected were H2, CO and CH4, indicating the potential for producing fuel gas and syngas from microalgae. PMID:26447558

  2. Effects of Pb(Ⅱ) exposure on Chlorella protothecoides and Chlorella vulgaris growth, malondialdehyde, and photosynthesis-related gene transcription.

    PubMed

    Xiong, Bang; Zhang, Wei; Chen, Lin; Lin, Kuang-Fei; Guo, Mei-Jin; Wang, Wei-Liang; Cui, Xin-Hong; Bi, Hua-Song; Wang, Bin

    2014-11-01

    Greater exposure to Pb(Ⅱ) increases the likelihood of harmful effects in the environment. In this study, the aquatic unicellular alga Chlorella protothecoides (C. protothecoides) and Chlorella vulgaris (C. vulgaris) were chosen to assess the acute and chronic toxicity of Pb(Ⅱ) exposure. Results of the observations show dose-response relationships could be clearly observed between Pb(Ⅱ) concentration and percentage inhibition (PI). Exposure to Pb(Ⅱ) increased malondialdehyde (MDA) content by up to 4.22 times compared with the control, suggesting that there was some oxidative damage. ANOVA analysis shows that Pb(Ⅱ) decreased chlorophyll (chl) content, indicating marked concentration-dependent relationships, and the lowest levels of chl a, chl b, and total-chl were 14.53, 18.80, and 17.95% of the controls, respectively. A real-time PCR assay suggests the changes in transcript abundances of three photosynthetic-related genes. After 120 h exposure Pb(Ⅱ) reduced the transcript abundance of rbcL, psaB, and psbC, and the relative abundances of the three genes of C. protothecoides and C. vulgaris in response to Pb(Ⅱ) were 54.66-98.59, 51.68-95.59, 37.89-95.48, 36.04-94.94, 41.19-91.20, and 58.75-96.80% of those of the controls, respectively. As for 28 d treatments, the three genes displayed similar inhibitory trend. This research provides a basic understanding of Pb(Ⅱ) toxicity to aquatic organisms.

  3. The culture of Chlorella vulgaris with human urine in multibiological life support system experiments

    NASA Astrophysics Data System (ADS)

    Li, Ming; Liu, Hong; Tong, Ling; Fu, Yuming; He, Wenting; Hu, Enzhu; Hu, Dawei

    The Integrative Experimental System (IES) was established as a tool to evaluate the rela-tionship of the subsystems in Bioregenerative Life Support System, and Multibiological Life Support System Experiments (MLSSE) have been conducted in the IES. The IES consists of a higher plant chamber, an animal chamber and a plate photo bioreactor (PPB) which cultivated lettuce (Lactuca sativa L.), silkworm (Bombyx Mori L.) and microalgae (Chlorella vulgaris), respectively. In MLSSE, four volunteers took turns breathing the system air through a tube connected with the animal chamber periodically. According to the CO2 concentration in the IES, the automotive control system of the PPB changed the light intensity regulating the photosynthesis of Chlorella vulgaris to make CO2 /O2 in the system maintain at stable levels. Chlorella vulgaris grew with human urine by carrying certain amount of alga liquid out of the bioreactor every day with synthetic urine replenished into the system, and O2 was regenerated, at the same time human urine was purified. Results showed that this IES worked stably and Chlorella vulgaris grew well; The culture of Chlorella vulgaris could be used to keep the balance of CO2 and O2 , and the change of light intensity could control the gas composition in the IES; Microalgae culture could be used in emergency in the system, the culture of Chlorella vulgaris could recover to original state in 5 days; 15.6 ml of condensation water was obtained every day by the culture of Chlorella vulgaris; The removal efficiencies of N, P in human urine could reach to 98.2% and 99.5%.

  4. Chlorella intake attenuates reduced salivary SIgA secretion in kendo training camp participants

    PubMed Central

    2012-01-01

    Background The green alga Chlorella contains high levels of proteins, vitamins, and minerals. We previously reported that a chlorella-derived multicomponent supplement increased the secretion rate of salivary secretory immunoglobulin A (SIgA) in humans. Here, we investigated whether intake of this chlorella-derived supplement attenuated the reduced salivary SIgA secretion rate during a kendo training camp. Methods Ten female kendo athletes participated in inter-university 6-day spring and 4-day summer camps. They were randomized into two groups; one took placebo tablets during the spring camp and chlorella tablets during the summer camp, while the other took chlorella tablets during the spring camp and placebo tablets during the summer camp. Subjects took these tablets starting 4 weeks before the camp until post-camp saliva sampling. Salivary SIgA concentrations were measured by ELISA. Results All subjects participated in nearly all training programs, and body-mass changes and subjective physical well-being scores during the camps were comparable between the groups. However, salivary SIgA secretion rate changes were different between these groups. Salivary SIgA secretion rates decreased during the camp in the placebo group (before vs. second, middle, and final day of camp, and after the camp: 146 ± 89 vs. 87 ± 56, 70 ± 45, 94 ± 58, and 116 ± 71 μg/min), whereas no such decreases were observed in the chlorella group (121 ± 53 vs. 113 ± 68, 98 ± 69,115 ± 80, and 128 ± 59 μg/min). Conclusion Our results suggest that a use of a chlorella-derived dietary supplement attenuates reduced salivary SIgA secretion during a training camp for a competitive sport. PMID:23227811

  5. Preliminary study of the green algae chlorella (Chlorella vulgaris) for control on the root-knot nematode (Meloidogyne arenaria) in tomato plants and ectoparasite Xiphinema indexin grape seedlings.

    PubMed

    Choleva, B; Bileva, T; Tzvetkov, Y; Barakov, P

    2005-01-01

    The alternative ecological methods require investigation of many organo-biological means for plant protection against dangerous root parasites such as root-knot nematode Meloidogyne arenaria and some ectoparasites (Xiphinema index). The Bulgarian organic product - dry extract of green alga Chlorella vulgaris ("The Golden Apple"-Plamen Barakov) is the latest product, which in comparative aspect gives the best results. Series of laboratory and pot experiments are carried out with tomato (cv. Bele and cv. Ideal) and grape seedlings (cv. Cabernet Sauvignon). Different dosages of Chlorella from 0.5 g to 2 g per plant/pot are investigated. The first results show that even low dosages had double effect - on the one hand they suppress the parasite development and on the other hand they strongly stimulate plant growing. The very important conclusion is that Chlorella vulgaris ignores the negative influence of M. arenaria and X. index. These results give us opportunity for future model and field investigations of Chlorella vulgaris with the aim of its practical application.

  6. Plastid and mitochondrion genomic sequences from Arctic Chlorella sp. ArM0029B

    PubMed Central

    2014-01-01

    Background Chorella is the representative taxon of Chlorellales in Trebouxiophyceae, and its chloroplast (cp) genomic information has been thought to depend only on studies concerning Chlorella vulgaris and GenBank information of C. variablis. Mitochondrial (mt) genomic information regarding Chlorella is currently unavailable. To elucidate the evolution of organelle genomes and genetic information of Chlorella, we have sequenced and characterized the cp and mt genomes of Arctic Chlorella sp. ArM0029B. Results The 119,989-bp cp genome lacking inverted repeats and 65,049-bp mt genome were sequenced. The ArM0029B cp genome contains 114 conserved genes, including 32 tRNA genes, 3 rRNA genes, and 79 genes encoding proteins. Chlorella cp genomes are highly rearranged except for a Chlorella-specific six-gene cluster, and the ArM0029B plastid resembles that of Chlorella variabilis except for a 15-kb gene cluster inversion. In the mt genome, 62 conserved genes, including 27 tRNA genes, 3 rRNA genes, and 32 genes encoding proteins were determined. The mt genome of ArM0029B is similar to that of the non-photosynthetic species Prototheca and Heicosporidium. The ArM0029B mt genome contains a group I intron, with an ORF containing two LAGLIDADG motifs, in cox1. The intronic ORF is shared by C. vulgaris and Prototheca. The phylogeny of the plastid genome reveals that ArM0029B showed a close relationship of Chlorella to Parachlorella and Oocystis within Chlorellales. The distribution of the cox1 intron at 721 support membership in the order Chlorellales. Mitochondrial phylogenomic analyses, however, indicated that ArM0029B shows a greater affinity to MX-AZ01 and Coccomyxa than to the Helicosporidium-Prototheca clade, although the detailed phylogenetic relationships among the three taxa remain to be resolved. Conclusions The plastid genome of ArM0029B is similar to that of C. variabilis. The mt sequence of ArM0029B is the first genome to be reported for Chlorella. Chloroplast

  7. Ingestion of Chlorella reduced the oxidation of erythrocyte membrane lipids in senior Japanese subjects.

    PubMed

    Miyazawa, Taiki; Nakagawa, Kiyotaka; Takekoshi, Hideo; Higuchi, Ohki; Kato, Shunji; Kondo, Momoko; Kimura, Fumiko; Miyazawa, Teruo

    2013-01-01

    Accumulation of phospholipid hydroperoxide (PLOOH) in erythrocyte membranes is an abnormality found in patients with senile dementia, including those with Alzheimer's disease. In our previous studies, dietary xanthophylls (polar carotenoids such as lutein) were hypothesized to inhibit lipid peroxidation. In the present study, we conducted a randomized, double-blind, placebo-controlled human trial to assess the impact for a total of 2 months Chlorella supplementation (8 g Chlorella/day/person; equivalent to 22.9 mg lutein/day/person) on PLOOH and carotenoid concentrations in erythrocytes as well as plasma of 12 normal senior subjects. After 1 or 2 months of treatment, erythrocytes and plasma lutein concentrations increased in the Chlorella group but not in the placebo group. In the Chlorella-supplemented group, erythrocyte PLOOH concentrations after a total of 2 months of treatment were lower than the concentrations before supplementation. These results suggest that Chlorella ingestion improved erythrocyte antioxidant status and lowered PLOOH concentrations. These reductions might contribute to maintaining the normal function of erythrocytes and prevent the development of senile dementia.

  8. [Effect of magnesium deficiency on photosynthetic physiology and triacylglyceride (TAG) accumulation of Chlorella vulgaris].

    PubMed

    Wang, Shan; Zhao, Shu-Xin; Wei, Chang-Long; Yu, Shui-Yan; Shi, Ji-Ping; Zhang, Bao-Guo

    2014-04-01

    As an excellent biological resource, Chlorella has wide applications for production of biofuel, bioactive substances and water environment restoration. Therefore, it is very important to understand the photosynthetic physiology characteristics of Chlorella. Magnesium ions play an important role in the growth of microalgae, not only the central atom of chlorophyll, but also the cofactor of some key enzyme in the metabolic pathway. A laboratory study was conducted to evaluate the effects of magnesium deficiency on several photosynthetic and physiological parameters and the triacylglyceride (TAG) accumulation of the green alga, Chlorella vulgaris, in the photoautotrophic culture process. Chlorella vulgaris biomass, protein, chlorophyll a and chlorophyll b contents decreased by 20%, 43.96%, 27.52% and 28.07% in response to magnesium deficiency, while the total oil content increased by 19.60%. Moreover, magnesium deficiency decreased the maximal photochemical efficiency F(v)/F(m) by 22.54%, but increased the non-photochemical quenching parameters qN. Our results indicated the decline of chlorophyll caused by magnesium, which affected the photosynthesis efficiency, lead to the growth inhibition of Chlorella vulgaris and affected the protein synthesis and increased the triacylglyceride (TAG) accumulation.

  9. [Using Excess Activated Sludge Treated 4-Chlorophenol Contained Waste Water to Cultivate Chlorella vulgaris].

    PubMed

    Wang, Lu; Chen, Xiu-rong; Yan, Long; He, Yi-xuan; Shi, Zhen-dong

    2015-04-01

    Using different rations of sludge extracts and supernate from 4-Chlorophenol (4-CP) simulated wastewater's excess sludge after centrifugation to cultivate the Chlorella vulgaris to achieve the goal of excess sludge utilization together with chlorella cultivating. The experiments were performed in 500 mL flasks with different rations of sludge extracts & BG-11 and supernate & BG-11 in a light growth chamber respectively. Number of algal cells, Chlorophyll, enzyme activity, oil and water total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), toxicity index were investigated. Result showed that the nutrition supplies and toxicity in the excess sludge were removed efficiently via Chlorella vulgaris, the removal rates of TN and TP were at least 40% and 90% respectively; After 10 days cultivation, the density growth of 50% sludge extracts was 20 times higher of the beginning while its chlorophyll content was lower than that of the blank group. Sludge extracts could promote the proliferation of algae, but were not conducive to the synthesis of chlorophyll. The quantity of SOD in per cell showed Chlorella vulgaris gave a positive response via stimulation from toxicant in sludge extracts and supernate. The best time for collecting chlorella vulgaris was the fifth day of cultivation, taking neutral oil accumulation as the evaluating indicator for its utilization combined with the removal of supplies and toxicity.

  10. Chlorella Virus Encoded Deoxyuridine triphosphatases Exhibit different Temperature Optima

    SciTech Connect

    Zhang,Y.; Moriyama, H.; Homma, K.; Van Etten, J.

    2005-01-01

    A putative deoxyuridine triphosphatase (dUTPase) gene from chlorella virus PBCV-1 was cloned, and the recombinant protein was expressed in Escherichia coli. The recombinant protein has dUTPase activity and requires Mg{sup 2+} for optimal activity, while it retains some activity in the presence of other divalent cations. Kinetic studies of the enzyme revealed a K{sub m} of 11.7 {mu}M, a turnover k{sub cat} of 6.8 s{sup -1}, and a catalytic efficiency of k{sub cat}/K{sub m} = 5.8 x 105 M{sup -1} s{sup -1}. dUTPase genes were cloned and expressed from two other chlorella viruses IL-3A and SH-6A. The two dUTPases have similar properties to PBCV-1 dUTPase except that IL-3A dUTPase has a lower temperature optimum (37{sup o}C) than PBCV-1 dUTPase (50{sup o}C). The IL-3A dUTPase differs from the PBCV-1 enzyme by nine amino acids, including two amino acid substitutions, Glu81{yields}Ser81 and Thr84{yields}Arg84, in the highly conserved motif III of the proteins. To investigate the difference in temperature optima between the two enzymes, homology modeling and docking simulations were conducted. The results of the simulation and comparisons of amino acid sequence suggest that adjacent amino acids are important in the temperature optima. To confirm this suggestion, three site-directed amino acid substitutions were made in the IL-3A enzyme: Thr84{yields}Arg84, Glu81{yields}Ser81, and Glu81{yields}Ser81 plus Thr84{yields}Arg84. The single substitutions affected the optimal temperature for enzyme activity. The temperature optimum increased from 37 to 55{sup o}C for the enzyme containing the two amino acid substitutions. We postulate that the change in temperature optimum is due to reduction in charge and balkiness in the active cavity that allows more movement of the ligand and protein before the enzyme and substrate complex is formed.

  11. Effects of nickel and pH on the growth of Chlorella vulgaris

    SciTech Connect

    Lustigman, B.; Lee, L.H.; Khalil, A.

    1995-07-01

    Chlorella is a spherical, unicellular, eukaryotic green algae. It is an obligate photoautotrophy containing chlorophylls a and b. It is a frequent symbiont of many other organisms such as paramecium, hydra and sponges and is important in fresh and marine environments, as well as in the soil. For these reasons, it has been suggested that Chlorella be used for metabolic studies as an indicator of environmental pollution. Ability of microorganisms to grow in environments containing high levels of toxic metals is frequently due to the organisms` capacity for adsorption of these ions and the role that they may play as essential cofactors in metalloenzymes as is the case for nickel. The purpose of this study was to determine the effect of nickel on the growth of Chlorella vulgaris. 19 refs., 4 figs., 1 tab.

  12. Peculiarities of the submicroscopic organization of chlorella cells cultivated on a solid medium in microgravity

    NASA Astrophysics Data System (ADS)

    Sytnik, K. M.; Popova, A. F.; Nechitailo, G. S.; Mashinsky, A. L.

    The submicroscopic organization of Chlorella vulgaris cells (strain LARG-1) growing over 30 days on a solid agarized medium aboard the orbital station ``Mir'' was studied. A number of differences in the ultrastructure of cells of the experimental population compared to the control has been revealed. Thus, changes in the membrane system of plastids, in particular, appearance of numerous vesicles of different diameter and outgrowths of the plastids and their contact with the plasmalemma as well as a considerable decrease of reserve polysaccharide number in the plastids. Moreover, an increase in the size of mitochondria, their cristae and lipid drops in cytoplasm, the formation of more complicated configuration folding of plasmalemma and appearance of small-granular material of mean electron density in the periplasmic space of Chlorella cells grown during space flight, are demonstrated. Comparative cytological analysis has revealed general regularities of rearrangements of the submicroscopic organization in Chlorella cells cultivated on both solid and semiliquid agarized nutrient media.

  13. Growth of Chlorella vulgaris and associated bacteria in photobioreactors

    PubMed Central

    Lakaniemi, Aino‐Maija; Intihar, Veera M.; Tuovinen, Olli H.; Puhakka, Jaakko A.

    2012-01-01

    Summary The aim of this study was to test three flat plate photobioreactor configurations for growth of Chlorella vulgaris under non‐axenic conditions and to characterize and quantify associated bacterial communities. The photobioreactor cultivations were conducted using tap water‐based media to introduce background bacterial population. Growth of algae was monitored over time with three independent methods. Additionally, the quantity and quality of eukaryotes and bacteria were analysed using culture‐independent molecular tools based on denaturing gradient gel electrophoresis (PCR‐DGGE) and quantitative polymerase chain reaction (QPCR). Static mixers used in the flat plate photobioreactors did not generally enhance the growth at the low light intensities used. The maximum biomass concentration and maximum specific growth rate were 1.0 g l−1 and 2.0 day−1 respectively. Bacterial growth as determined by QPCR was associated with the growth of C. vulgaris. Based on PCR‐DGGE, bacteria in the cultures mainly originated from the tap water. Bacterial community profiles were diverse but reproducible in all flat plate cultures. Most prominent bacteria in the C. vulgaris cultures belonged to the class Alphaproteobacteria and especially to the genus Sphingomonas. Analysis of the diversity of non‐photosynthetic microorganisms in algal mass cultures can provide useful information on the public health aspects and unravel community interactions. PMID:21936882

  14. Toxicological Responses of Chlorella vulgaris to Dichloromethane and Dichloroethane

    PubMed Central

    Wu, Shijin; Zhang, Huaxing; Yu, Xiang; Qiu, Lequan

    2014-01-01

    Abstract The aim of this study was to evaluate the acute toxicity effects of dichloromethane and dichloroethane on Chlorella vulgaris at the physiological and molecular level. Data showed that the cell number, chlorophyll a, and total protein content gradually decreased with increasing dichloromethane and dichloroethane concentrations over a 96-h exposure. Lower doses of two organic solvents had stimulatory effects on catalase and superoxide dismutase activity. Malondialdehyde showed a concentration-dependent increase in response to dichloromethane and dichloroethane exposure. Electron microscopy also showed that there were some chloroplast abnormalities in response to different concentrations of dichloromethane and dichloroethane exposure. Real-time polymerase chain reaction assay demonstrated that dichloromethane and dichloroethane reduced the transcript abundance of psaB, whereas that of psbC changed depending on the toxicant after 24 h of exposure. Dichloromethane and dichloroethane affected the activity of antioxidant enzymes, disrupted the chloroplast ultrastructure, and reduced transcription of photosynthesis-related genes in C. vulgaris, leading to metabolic disruption and cell death. PMID:24550665

  15. Physiological and biochemical responses of Chlorella vulgaris to Congo red.

    PubMed

    Hernández-Zamora, Miriam; Perales-Vela, Hugo Virgilio; Flores-Ortíz, César Mateo; Cañizares-Villanueva, Rosa Olivia

    2014-10-01

    Extensive use of synthetic dyes in many industrial applications releases large volumes of wastewater. Wastewaters from dying industries are considered hazardous and require careful treatment prior to discharge into receiving water bodies. Dyes can affect photosynthetic activities of aquatic flora and decrease dissolved oxygen in water. The aim of this study was to evaluate the effect of Congo red on growth and metabolic activity of Chlorella vulgaris after 96h exposure. Exposure of the microalga to Congo red reduced growth rate, photosynthesis and respiration. Analysis of chlorophyll a fluorescence emission showed that the donor side of photosystem II was affected at high concentrations of Congo red. The quantum yield for electron transport (φEo), the electron transport rate (ETR) and the performance index (PI) also decreased. The reduction in the ability to absorb and use the quantum energy increased non-photochemical (NPQ) mechanisms for thermal dissipation. Overall, Congo red affects growth and metabolic activity in photosynthetic organisms in aquatic environments. PMID:25042247

  16. Enhancement of hydrolysis of Chlorella vulgaris by hydrochloric acid.

    PubMed

    Park, Charnho; Lee, Ja Hyun; Yang, Xiaoguang; Yoo, Hah Young; Lee, Ju Hun; Lee, Soo Kweon; Kim, Seung Wook

    2016-06-01

    Chlorella vulgaris is considered as one of the potential sources of biomass for bio-based products because it consists of large amounts of carbohydrates. In this study, hydrothermal acid hydrolysis with five different acids (hydrochloric acid, nitric acid, peracetic acid, phosphoric acid, and sulfuric acid) was carried out to produce fermentable sugars (glucose, galactose). The hydrothermal acid hydrolysis by hydrochloric acid showed the highest sugar production. C. vulgaris was hydrolyzed with various concentrations of hydrochloric acid [0.5-10 % (w/w)] and microalgal biomass [20-140 g/L (w/v)] at 121 °C for 20 min. Among the concentrations examined, 2 % hydrochloric acid with 100 g/L biomass yielded the highest conversion of carbohydrates (92.5 %) into reducing sugars. The hydrolysate thus produced from C. vulgaris was fermented using the yeast Brettanomyces custersii H1-603 and obtained bioethanol yield of 0.37 g/g of algal sugars. PMID:26899601

  17. Changes in salivary flow rate following Chlorella-derived multicomponent supplementation.

    PubMed

    Otsuki, Takeshi; Shimizu, Kazuhiro; Zempo-Miyaki, Asako; Maeda, Seiji

    2016-07-01

    Decreases in saliva secretion compromise food mastication and swallowing, reduce mucosal immune function, and increase the risk for oral diseases like dental caries. Chlorella is a green alga that contains a variety of nutrients including amino acids, vitamins, and minerals. In our previous study, Chlorella-derived multicomponent supplementation did not affect salivary flow rates in healthy young individuals, but Chlorella-derived supplementation attenuated a decrease in saliva secretion that was observed during a kendo training camp. Hence, we hypothesized that Chlorella-derived supplementation increases saliva secretion in individuals with lower rates of saliva flow. Sixty-four subjects took Chlorella-derived tablets for four weeks. Before and after supplementation, saliva samples were collected by chewing cotton. In the complete study group, there was no difference in saliva production before and after supplementation (1.91 ± 0.11 ml/min before vs 2.01 ± 0.12 ml/min after). Analysis of subgroups based on saliva production before supplementation found an increase in saliva secretion in the lower saliva flow group (1.18 ± 0.06 vs 1.38 ± 0.08 ml/min), but no change in the higher saliva flow group (2.63 ± 0.11 vs 2.64 ± 0.15 ml/min). These results suggest that Chlorella-derived multicomponent supplementation increases saliva production in individuals with lower levels of saliva secretion. PMID:27499578

  18. The Tissue Distribution of Lutein in Laying Hens Fed Lutein Fortified Chlorella and Production of Chicken Eggs Enriched with Lutein

    PubMed Central

    An, Byoung-Ki; Jeon, Jin-Young; Kang, Chang-Won; Kim, Jin-Man

    2014-01-01

    Two experiments were conducted to investigate the dietary effects of conventional or lutein fortified chlorella on lutein absorptions, the tissue distributions and the changes in lutein content of eggs in laying hens. In Exp 1, a total of one hundred and fifty, 70 wk-old Hy-Line brown layers were divided into three groups with five replicates and fed with each experiment diet (control diet, diet with 1% conventional chlorella or lutein fortified chlorella) for 2 wk, respectively. The egg production in groups fed diets containing both chlorella powders were higher than that of the control group (p<0.01). With chlorella supplementations, the yolk color significantly increased, although there were no significant differences in the eggshell qualities. The lutein contents of serum, liver and growing oocytes were greatly increased by feeding conventional or lutein fortified chlorella (p<0.01). In Exp. 2, a total of ninety 60 wk-old Hy-Line brown layers were assigned into three groups with three replicates per group (10 birds per replicate). The birds were fed with one of three experimental diets (0, 0.1 or 0.2% lutein fortified chlorella) for 2 wk, respectively. The egg production was not affected by dietary treatments. The egg weight in the group fed with diet containing 0.2% of lutein fortified chlorella was higher than that of the control (p<0.05). As the dietary chlorella levels increased, the daily egg mass linearly increased, although not significantly. The yolk colors in groups fed diets containing lutein fortified chlorella were dramatically increased as compared to the control (p<0.001). The lutein in chicken eggs significantly increased when fed with 0.2% of lutein fortified chlorella (p<0.01). These results suggested that the dietary lutein derived from chlorella was readily absorbed into the serum and absorbed by the liver with growing oocyte for commercial laying hens. Particularly, the lutein fortified chlorella was a valuable natural source for the

  19. Complete genome sequence of mitochondrial DNA (mtDNA) of Chlorella sorokiniana.

    PubMed

    Orsini, Massimiliano; Costelli, Cristina; Malavasi, Veronica; Cusano, Roberto; Concas, Alessandro; Angius, Andrea; Cao, Giacomo

    2016-01-01

    The complete sequence of mitochondrial genome of the Chlorella sorokiniana strain (SAG 111-8 k) is presented in this work. Within the Chlorella genus, it represents the second species with a complete sequenced and annotated mitochondrial genome (GenBank accession no. KM241869). The genome consists of circular chromosomes of 52,528 bp and encodes a total of 31 protein coding genes, 3 rRNAs and 26 tRNAs. The overall AT contents of the C. sorokiniana mtDNA is 70.89%, while the coding sequence is of 97.4%.

  20. An improved colony PCR procedure for genetic screening of Chlorella and related microalgae.

    PubMed

    Wan, Minxi; Rosenberg, Julian N; Faruq, Junaid; Betenbaugh, Michael J; Xia, Jinlan

    2011-08-01

    A colony PCR technique was applied for both genomic and chloroplast DNA in the green microalgae Chlorella. Of five different lysis buffers, Chelex-100 was superior for DNA extraction, PCR and DNA storage. It also was insensitive to variations in cell density. The conditions established for an improved PCR formulation are applicable for screening of genetically-engineered transformants as well as bioprospecting of natural microalgal isolates. Besides multiple Chlorella species, we also demonstrate the efficacy of Chelex-100 for colony PCR with a number of other microalgal strains, including Chlamydomonas reinhardtii, Dunaliella salina, Nannochloropsis sp., Coccomyxa sp., and Thalassiosira pseudonana.

  1. The acclimation of Chlorella to high-level nitrite for potential application in biological NOx removal from industrial flue gases.

    PubMed

    Li, Tianpei; Xu, Gang; Rong, Junfeng; Chen, Hui; He, Chenliu; Giordano, Mario; Wang, Qiang

    2016-05-20

    Nitrogen oxides (NOx) are the components of fossil flue gas that give rise to the greatest environmental concerns. This study evaluated the ability of the green algae Chlorella to acclimate to high level of NOx and the potential utilization of Chlorella strains in biological NOx removal (DeNOx) from industrial flue gases. Fifteen Chlorella strains were subject to high-level of nitrite (HN, 176.5 mmolL(-1) nitrite) to simulate exposure to high NOx. These strains were subsequently divided into four groups with respect to their ability to tolerate nitrite (excellent, good, fair, and poor). One strain from each group was selected to evaluate their photosynthetic response to HN condition, and the nitrite adaptability of the four Chlorella strains were further identified by using chlorophyll fluorescence. The outcome of our experiments shows that, although high concentrations of nitrite overall negatively affect growth and photosynthesis of Chlorella strains, the degree of nitrite tolerance is a strain-specific feature. Some Chlorella strains have an appreciably higher ability to acclimate to high-level of nitrite. Acclimation is achieved through a three-step process of restrict, acclimate, and thriving. Notably, Chlorella sp. C2 was found to have a high tolerance and to rapidly acclimate to high concentrations of nitrite; it is therefore a promising candidate for microalgae-based biological NOx removal.

  2. The acclimation of Chlorella to high-level nitrite for potential application in biological NOx removal from industrial flue gases.

    PubMed

    Li, Tianpei; Xu, Gang; Rong, Junfeng; Chen, Hui; He, Chenliu; Giordano, Mario; Wang, Qiang

    2016-05-20

    Nitrogen oxides (NOx) are the components of fossil flue gas that give rise to the greatest environmental concerns. This study evaluated the ability of the green algae Chlorella to acclimate to high level of NOx and the potential utilization of Chlorella strains in biological NOx removal (DeNOx) from industrial flue gases. Fifteen Chlorella strains were subject to high-level of nitrite (HN, 176.5 mmolL(-1) nitrite) to simulate exposure to high NOx. These strains were subsequently divided into four groups with respect to their ability to tolerate nitrite (excellent, good, fair, and poor). One strain from each group was selected to evaluate their photosynthetic response to HN condition, and the nitrite adaptability of the four Chlorella strains were further identified by using chlorophyll fluorescence. The outcome of our experiments shows that, although high concentrations of nitrite overall negatively affect growth and photosynthesis of Chlorella strains, the degree of nitrite tolerance is a strain-specific feature. Some Chlorella strains have an appreciably higher ability to acclimate to high-level of nitrite. Acclimation is achieved through a three-step process of restrict, acclimate, and thriving. Notably, Chlorella sp. C2 was found to have a high tolerance and to rapidly acclimate to high concentrations of nitrite; it is therefore a promising candidate for microalgae-based biological NOx removal. PMID:27010349

  3. [Isolation, Identification and Characteristic Analysis of an Oil-producing Chlorella sp. Tolerant to High-strength Anaerobic Digestion Effluent].

    PubMed

    Yang, Chuang; Wang, Wen-guo; Ma, Dan-wei; Tang, Xiao-yu; Hu, Qi-chun

    2015-07-01

    A Chlorella strain tolerant to high-strength anaerobic digestion effluent was isolated from the anaerobic digestion effluent with a long-term exposure to air. The strain was identified as a Chlorella by morphological and molecular biological methods, and named Chlorella sp. BWY-1, The anaerobic digestion effluent used in this study was from a biogas plant with the raw materials of swine wastewater after solid-liquid separation. The Chlorella regularis (FACHB-729) was used as the control strain. The comparative study showed that Chlorella sp, BWY-Ihad relatively higher growth rate, biomass accumulation capacity and pollutants removal rate in BG11. and different concentrations of anaerobic digestion effluent. Chlorella sp. BWY-1 had the highest growth rate and biomass productivity (324.40 mg.L-1) in BG11, but its lipid productivity and lipid content increased with the increase of anaerobic digestion effluent concentration, In undiluted anaerobic digestion effluent, the lipid productivity and lipid content of Chlorella sp. BWY-1 were up to 44. 43% and 108. 70 mg.L-1, respectively. Those results showed that the isolated algal strain bad some potential applications in livestock wastewater treatment and bioenergy production, it could be combined with a solid-liquid separation, anaerobic fermentation and other techniques for processing livestock wastewater and producing biodiesel.

  4. Characterization of iron uptake from hydroxamate siderophores by Chlorella vulgaris

    SciTech Connect

    Allnutt, F.C.T.

    1985-01-01

    Iron uptake by Chlorella vulgaris from ferric-hydroxamate siderophores and the possible production of siderophores by these algae was investigated. No production of siderophores or organic acids was observed. Iron from the two hydroxamate siderophores tested, ferrioximine B (Fe/sup 3 +/-DFOB) and ferric-rhodotorulate (Fe/sup 3 +/-RA), was taken up at the same rate as iron chelated by citrate or caffeate. Two synthetic chelates, Fe/sup 3 +/-EDTA and Fe/sup 3 +/-EDDHA, provided iron at a slower rate. Iron uptake was inhibited by 50 ..mu..M CCCP or 1 mM vanadate. Cyanide (100 ..mu..M KCN) or 25 ..mu..M antimycin A failed to demonstrate a link between uptake and respiration. Labeled iron (/sup 55/Fe) was taken up while labeled ligands ((/sup 14/C) citrate or RA) were not accumulated. Cation competition from Ni/sup 2 +/ and Co/sup 2 +/ observed using Fe/sup 3 +/-DFOB and Fe/sup 3 +/-RA while iron uptake from Fe/sup 3 +/-citrate was stimulated. Iron-stress induced iron uptake from the hydroxamate siderophores. Ferric reduction from the ferric-siderophores was investigated with electron paramagnetic resonance (EPR) and bathophenathroline disulfonate (BPDS). Ferric reduction was induced by iron-stress and inhibited by CCCP. A close correlation between iron uptake and ferric reduction was measured by the EPR method. Ferric reduction measured by the BPDS method was greater than that measure by EPR. BPDS reduction was interpreted to indicate a potential for reduction while EPR measures the physiological rate of reduction. BPDS inhibition of iron uptake and ferricyanide interference with reduction indicate that reduction and uptake occur exposed to the external medium. Presumptive evidence using a binding dose response curve for Fe/sup 3 +/-DFOB indicated that a receptor may be involved in this mechanism.

  5. First case of Chlorella wound infection in a human in Australia

    PubMed Central

    Hart, J; Mooney, L; Arthur, I; Inglis, T J J; Murray, R

    2014-01-01

    A 30-year-old man developed an infected knee wound 2 days after jumping his bicycle into a freshwater dam. He required repeated debridement and tissue grew bright green colonies typical of the alga Chlorella plus Aeromonas hydrophila. This, and one previously reported case, responded to surgical debridement and careful wound management. PMID:25356359

  6. Sources of mycosporine-like amino acids in planktonic Chlorella-bearing ciliates (Ciliophora)

    PubMed Central

    SONNTAG, BETTINA; SUMMERER, MONIKA; SOMMARUGA, RUBEN

    2007-01-01

    Mycosporine-like amino acids (MAAs) are a family of secondary metabolites known to protect organisms exposed to solar UV radiation. We tested their distribution among several planktonic ciliates bearing Chlorella isolated from an oligo-mesotrophic lake in Tyrol, Austria. In order to test the origin of these compounds, the MAAs were assessed by high performance liquid chromatography in both the ciliates and their symbiotic algae. Considering all Chlorella-bearing ciliates, we found: (i) seven different MAAs (mycosporine-glycine, palythine, asterina-330, shinorine, porphyra-334, usujirene, palythene); (ii) one to several MAAs per species and (iii) qualitative and quantitative seasonal changes in the MAAs (e.g. in Pelagodileptus trachelioides). In all species tested, concentrations of MAAs were always <1% of ciliate dry weight. Several MAAs were also identified in the Chlorella isolated from the ciliates, thus providing initial evidence for their symbiotic origin. In Uroleptus sp., however, we found evidence for a dietary source of MAAs. Our results suggest that accumulation of MAAs in Chlorella-bearing ciliates represents an additional benefit of this symbiosis and an adaptation for survival in sunlit, UV-exposed waters.

  7. Vitmin A, nutrition, and health values of algea: spirulina, chlorella, and dunaliella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spirulina, chlorella, and dunalliella are unicellular algae that are commercially produced worldwide. These algae are concentrated sources of carotenoids (especially provitamin A carotenoids) and other nutrients, such as vitamin B12. Their health benefits as a complementary dietary source for macro ...

  8. The Use of Chlorella Vulgaris in a Simple Demonstration of Heavy Metal Toxicity.

    ERIC Educational Resources Information Center

    Gipps, J. F.; Biro, P.

    1978-01-01

    An experimental system, suitable for secondary schools, uses Chlorella vulgaris to demonstrate the effects of mercury and cadmium. Very low concentrations of mercury or cadmium decrease growth, whereas lead or arsenic have little effect. Further experiments show additive interactions between mercury and cadmium and antagonistic interactions…

  9. Effect of dried Chlorella vulgaris and Chlorella growth factor on growth performance, meat qualities and humoral immune responses in broiler chickens.

    PubMed

    An, Byoung-Ki; Kim, Kwan-Eung; Jeon, Jin-Young; Lee, Kyung Woo

    2016-01-01

    This experiment was carried out to investigate the effects of dried chlorella powder (Chlorella vulgaris; DCP) and chlorella growth factor (CGF) on growth performance, serum characteristics, meat qualities and humoral immune responses in broiler chicks. A total of 1050 day-old Ross male broiler chicks were randomly divided into 35 pens (30 chicks/pen) and subjected to one of seven dietary treatments. A non-medicated corn-soybean meal base diet was considered as negative control (NC) and added with either antibiotic (PC), three levels of DCP (NC diets added with 0.05, 0.15 or 0.5 % DCP) or two levels of CGF (NC diets added with 0.05 or 0.15 % CGF). The final body weight and daily weight gain in PC and groups fed diets with 0.15 or 0.5 % DCP were heavier (p < 0.001) than those of NC and CGF-treated groups. Serum total lipid concentrations were lower (p = 0.001) in groups fed diets with 0.5 % DCP and 0.05 or 0.15 % CGF compared with PC group. The levels of serum IgG (p = 0.050) and IgM (p = 0.010) were elevated in chicks fed diets with DCP and CGF compared with the PC or NC group. Meat qualities such as cooking loss, meat color, and pH, of edible meats were not altered by dietary treatments. Collectively, these results indicate that dietary DCP, but not CGF, exerted growth-promoting effect, and both DCP and CGF affected humoral immune response in broiler chicks. PMID:27375987

  10. Effect of dried Chlorella vulgaris and Chlorella growth factor on growth performance, meat qualities and humoral immune responses in broiler chickens.

    PubMed

    An, Byoung-Ki; Kim, Kwan-Eung; Jeon, Jin-Young; Lee, Kyung Woo

    2016-01-01

    This experiment was carried out to investigate the effects of dried chlorella powder (Chlorella vulgaris; DCP) and chlorella growth factor (CGF) on growth performance, serum characteristics, meat qualities and humoral immune responses in broiler chicks. A total of 1050 day-old Ross male broiler chicks were randomly divided into 35 pens (30 chicks/pen) and subjected to one of seven dietary treatments. A non-medicated corn-soybean meal base diet was considered as negative control (NC) and added with either antibiotic (PC), three levels of DCP (NC diets added with 0.05, 0.15 or 0.5 % DCP) or two levels of CGF (NC diets added with 0.05 or 0.15 % CGF). The final body weight and daily weight gain in PC and groups fed diets with 0.15 or 0.5 % DCP were heavier (p < 0.001) than those of NC and CGF-treated groups. Serum total lipid concentrations were lower (p = 0.001) in groups fed diets with 0.5 % DCP and 0.05 or 0.15 % CGF compared with PC group. The levels of serum IgG (p = 0.050) and IgM (p = 0.010) were elevated in chicks fed diets with DCP and CGF compared with the PC or NC group. Meat qualities such as cooking loss, meat color, and pH, of edible meats were not altered by dietary treatments. Collectively, these results indicate that dietary DCP, but not CGF, exerted growth-promoting effect, and both DCP and CGF affected humoral immune response in broiler chicks.

  11. Biomass and lipid production of a local isolate Chlorella sorokiniana under mixotrophic growth conditions.

    PubMed

    Juntila, D J; Bautista, M A; Monotilla, W

    2015-09-01

    A local Chlorella sp. isolate with 97% rbcL sequence identity to Chlorella sorokiniana was evaluated in terms of its biomass and lipid production under mixotrophic growth conditions. Glucose-supplemented cultures exhibited increasing growth rate and biomass yield with increasing glucose concentration. Highest growth rate and biomass yield of 1.602 day(-1) and 687.5 mg L(-1), respectively, were achieved under 2 g L(-1) glucose. Nitrogen starvation up to 75% in the 1.0 g L(-1) glucose-supplemented culture was done to induce lipid accumulation and did not significantly affect the growth. Lipid content ranges from 20% to 27% dry weight. Nile Red staining showed more prominent neutral lipid bodies in starved mixotrophic cultures. C. sorokiniana exhibited enhanced biomass production under mixotrophy and more prominent neutral lipid accumulation under nitrogen starvation with no significant decrease in growth; hence, this isolate could be further studied to establish its potential for biodiesel production. PMID:25847795

  12. Hydrolysis of Chlorella by Cellulomonas sp. YJ5 cellulases and its biofunctional properties.

    PubMed

    Yin, Li-Jung; Jiang, Shann-Tzong; Pon, Shen-Hwei; Lin, Hsin-Hung

    2010-01-01

    Both 10% and 20% (w/w) Chlorella suspensions were hydrolyzed by 150 to 350 U/mL of cellulases from a 3-d cultivation of Cellulomonas sp. YJ5. Higher chlorophyll, reducing sugars and soluble proteins, and lower residual insoluble solid were observed on both samples after 30-min hydrolysis by various concentrations of cellulases at 50 °C. Decrease in insoluble solid, increases in soluble proteins, peptides and chlorophyll contents, and microscopic observation indicated obvious lysis of cell walls occurred during 60- to 180-min hydrolysis. Significant increases in soluble proteins, peptides, Fe(2+) chelating ability, trolox equivalent antioxidation capacity (TEAC), and reducing power was obtained after 3-h hydrolysis by 150 U/mL of cellulase. These data suggested that cellulolysis technology has high application potential in Chlorella industry.

  13. Improving cell growth and lipid accumulation in green microalgae Chlorella sp. via UV irradiation.

    PubMed

    Liu, Shuyu; Zhao, Yueping; Liu, Li; Ao, Xiyong; Ma, Liyan; Wu, Minghong; Ma, Fang

    2015-04-01

    Microalgae with high biomass and high lipid content are the ideal feedstock for biodiesel production. To obtain such microalgae, ultraviolet (UV) irradiation was applied to Chlorella sp. to induce mutagenesis. The growth characteristics, total nitrogen (TN), and biochemical compositions of the control and UV mutation strains were analyzed. Compared to the control strain, the biomass for the UV mutation strain was 7.6 % higher and it presented a higher growth rate. The lipid content of the UV mutation strain showed different levels of increase and reached the maximum value of 28.1 % on day 15. Furthermore, the lipid productivity of the UV mutation strain showed a desired increase. The nitrogen consumption and Acetyl-CoA carboxylase (ACC) activity contributed to the lipid production by UV. All these results indicate that UV mutagenesis is an efficient method to improve probability for using Chlorella sp. as the potential raw material for biodiesel production.

  14. Cultivation of microalgal Chlorella for biomass and lipid production using wastewater as nutrient resource.

    PubMed

    Chiu, Sheng-Yi; Kao, Chien-Ya; Chen, Tsai-Yu; Chang, Yu-Bin; Kuo, Chiu-Mei; Lin, Chih-Sheng

    2015-05-01

    Using wastewater for microalgal cultures is beneficial for minimizing the use of freshwater, reducing the cost of nutrient addition, removing nitrogen and phosphorus from wastewater and producing microalgal biomass as bioresources for biofuel or high-value by-products. There are three main sources of wastewater, municipal (domestic), agricultural and industrial wastewater, which contain a variety of ingredients. Some components in the wastewater, such as nitrogen and phosphorus, are useful ingredients for microalgal cultures. In this review, the effects on the biomass and lipid production of microalgal Chlorella cultures using different kinds of wastewater were summarized. The use of the nutrients resource in wastewater for microalgal cultures was also reviewed. The effect of ammonium in wastewater on microalgal Chlorella growth was intensively discussed. In the end, limitations of wastewater-based of microalgal culture were commented in this review article.

  15. Biomass and lipid production of a local isolate Chlorella sorokiniana under mixotrophic growth conditions.

    PubMed

    Juntila, D J; Bautista, M A; Monotilla, W

    2015-09-01

    A local Chlorella sp. isolate with 97% rbcL sequence identity to Chlorella sorokiniana was evaluated in terms of its biomass and lipid production under mixotrophic growth conditions. Glucose-supplemented cultures exhibited increasing growth rate and biomass yield with increasing glucose concentration. Highest growth rate and biomass yield of 1.602 day(-1) and 687.5 mg L(-1), respectively, were achieved under 2 g L(-1) glucose. Nitrogen starvation up to 75% in the 1.0 g L(-1) glucose-supplemented culture was done to induce lipid accumulation and did not significantly affect the growth. Lipid content ranges from 20% to 27% dry weight. Nile Red staining showed more prominent neutral lipid bodies in starved mixotrophic cultures. C. sorokiniana exhibited enhanced biomass production under mixotrophy and more prominent neutral lipid accumulation under nitrogen starvation with no significant decrease in growth; hence, this isolate could be further studied to establish its potential for biodiesel production.

  16. Large-scale production and plaque titration of European Chlorella viruses.

    PubMed

    Bornemann, C; Follmann, H

    1997-09-01

    Viruses of the exsymbiotic green freshwater algae Chlorella, family Phycodnaviridae, appear to be distributed worldwide but those found in North American algae have been characterized in detail. The distinct European Chlorella viruses were studied and it was necessary to adapt both large scale purification and the plaque titration assay to the host organisms' different physiology and to our specific laboratory needs. In the virus purification scheme, a precipitation step with polyethylene glycol was introduced which allows high yield recovery of infective particles from large volumes by rapid low-speed centrifugation. In the plaque assay, a standardized algal culture was introduced. The influence of other factors, e.g. circadian rhythm, on plaque growth is also described.

  17. Utilization of carbon dioxide in industrial flue gases for the cultivation of microalga Chlorella sp.

    PubMed

    Kao, Chien-Ya; Chen, Tsai-Yu; Chang, Yu-Bin; Chiu, Tzai-Wen; Lin, Hsiun-Yu; Chen, Chun-Da; Chang, Jo-Shu; Lin, Chih-Sheng

    2014-08-01

    The biomass and lipid productivity of Chlorella sp. MTF-15 cultivated using aeration with flue gases from a coke oven, hot stove or power plant in a steel plant of the China Steel Corporation in Taiwan were investigated. Using the flue gas from the coke oven, hot stove or power plant for cultivation, the microalgal strain obtained a maximum specific growth rate and lipid production of (0.827 d(-1), 0.688 g L(-1)), (0.762 d(-1), 0.961 g L(-1)), and (0.728 d(-1), 0.792 g L(-1)), respectively. This study demonstrated that Chlorella sp. MTF-15 could efficiently utilize the CO₂, NOX and SO₂ present in the different flue gases. The results also showed that the growth potential, lipid production and fatty acid composition of the microalgal strain were dependent on the composition of the flue gas and on the operating strategy deployed.

  18. Comparative toxicity and structure-activity in Chlorella and Tetrahymena: Monosubstituted phenols

    SciTech Connect

    Jaworska, J.S.; Schultz, T.W. )

    1991-07-01

    The relative toxicity of selected monosubstituted phenols has been assessed by Kramer and Truemper in the Chlorella vulgaris assay. The authors examined population growth inhibition of this simple green algae under short-term static conditions for 33 derivatives. However, efforts to develop a strong predictive quantitative structure-activity relationship (QSAR) met with limited success because they modeled across modes of toxic action or segregated derivatives such as positional isomers (i.e., ortho-, meta-, para-). In an effort to further their understanding of the relationships of ecotoxic effects of phenols, the authors have evaluated the same derivatives reported by Kramer and Truemper in the Tetrahymena pyriformis population growth assay, compared the responses in both systems and developed QSARs for the Chlorella vulgaris data based on mechanisms of action.

  19. Caleosin from Chlorella vulgaris TISTR 8580 is salt-induced and heme-containing protein.

    PubMed

    Charuchinda, Pairpilin; Waditee-Sirisattha, Rungaroon; Kageyama, Hakuto; Yamada, Daisuke; Sirisattha, Sophon; Tanaka, Yoshito; Mahakhant, Aparat; Takabe, Teruhiro

    2015-01-01

    Physiological and functional properties of lipid droplet-associated proteins in algae remain scarce. We report here the caleosin gene from Chlorella vulgaris encodes a protein of 279 amino acid residues. Amino acid sequence alignment showed high similarity to the putative caleosins from fungi, but less to plant caleosins. When the C. vulgaris TISTR 8580 cells were treated with salt stress (0.3 M NaCl), the level of triacylglycerol increased significantly. The mRNA contents for caleosin in Chlorella cells significantly increased under salt stress condition. Caleosin gene was expressed in E. coli. Crude extract of E. coli cells exhibited the cumene hydroperoxide-dependent oxidation of aniline. Absorption spectroscopy showed a peak around 415 nm which was decreased upon addition of cumene hydroperoxide. Native polyacrylamide gel electrophoresis suggests caleosin existed as the oligomer. These data indicate that a fresh water C. vulgaris TISTR 8580 contains a salt-induced heme-protein caleosin. PMID:25703935

  20. Nitrogen balancing and xylose addition enhances growth capacity and protein content in Chlorella minutissima cultures.

    PubMed

    Freitas, B C B; Esquível, M G; Matos, R G; Arraiano, C M; Morais, M G; Costa, J A V

    2016-10-01

    This study aimed to examine the metabolic changes in Chlorella minutissima cells grown under nitrogen-deficient conditions and with the addition of xylose. The cell density, maximum photochemical efficiency, and chlorophyll and lipid levels were measured. The expression of two photosynthetic proteins, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and the beta subunit (AtpB) of adenosine triphosphate synthase, were measured. Comparison of cells grown in medium with a 50% reduction in the nitrogen concentration versus the traditional medium solution revealed that the cells grown under nitrogen-deficient conditions exhibited an increased growth rate, higher maximum cell density (12.7×10(6)cellsmL(-1)), optimal PSII efficiency (0.69) and decreased lipid level (25.08%). This study has taken the first steps toward protein detection in Chlorella minutissima, and the results can be used to optimize the culturing of other microalgae. PMID:27359061

  1. Population of Vibrational State of Carotenoid Molecules in Living Cells of Chlorella

    NASA Astrophysics Data System (ADS)

    Kinoshita, Shuichi; Hirata, Kuniko; Kushida, Takashi

    1980-07-01

    Stokes and anti-Stokes Raman spectra have been measured in living cells of Chlorella vulgaris as well as in chloroform, toluene, benzene and β-carotene. Population in the vibrational state has been determined by taking account of resonance Raman effect. The result shows that this population is well explained by thermal distribution even in the case of living biological cells, contrary to recently reported observation of some population enhancement. Possible experimental artifacts are discussed.

  2. [Effect of adaptation to light of different spectral composition on photosynthesis of Chlorella cells].

    PubMed

    Brandt, A B; Kiseleva, M I

    1980-01-01

    Dependence of cell photosynthesis in different spectral regions on illumination conditions of chlorella culture during growing (blue, green and red light) was studied. Change in the shape of action spectra of photosynthesis (measured with interference light filters) was discovered. This change is mostly pronounced in relation to the red and blue maxima. The largest relative value of the blue maximum was observed for the cells grown in the red light.

  3. Physicochemical effects on sulfite transformation in a lipid-rich Chlorella sp. strain

    NASA Astrophysics Data System (ADS)

    Liang, Fang; Wen, Xiaobin; Luo, Liming; Geng, Yahong; Li, Yeguang

    2014-11-01

    SO2 is very rapidly hydrated to sulfurous acid in water solution at pH value above 6.0, whereby sulfite is yielded from the disassociation of protons. We aimed to improve the sulfite transformation efficiency and provide a basis for the direct utilization of SO2 from flue gas by a microalgal suspension. Chlorella sp. XQ-20044 was cultured in a medium with 20 mmol/L sodium sulfite under different physicochemical conditions. Under light conditions, sulfite concentration in the algal suspension reduced linearly over time, and was completely converted into sulfate within 8 h. The highest sulfite transformation rate (3.25 mmol/(L·h)) was obtained under the following conditions: 35°C, light intensity of 300 μmol/(m2·s), NaHCO3 concentration of 6 g/L, initial cell density (OD540) of 0.8 and pH of 9-10. There was a positive correlation between sulfite transformation rate and the growth of Chlorella, with the conditions favorable to algal growth giving better sulfite transformation. Although oxygen in the air plays a role in the transformation of SO2- 3 to SO2- 4, the transformation is mainly dependent on the metabolic activity of algal cells. Chlorella sp. XQ-20044 is capable of tolerating high sulfite concentration, and can utilize sulfite as the sole sulfur source for maintaining healthy growth. We found that sulfite ≤20 mmol/L had no obvious effect on the total lipid content and fatty acid profiles of the algae. Thus, the results suggest it is feasible to use flue gas for the mass production of feedstock for biodiesel using Chlorella sp. XQ-20044, without preliminary removal of SO2, assuming there is adequate control of the pH.

  4. Cultivation of Chlorella on brewery wastewater and nano-particle biosynthesis by its biomass.

    PubMed

    Subramaniyam, Vidhyasri; Subashchandrabose, Suresh Ramraj; Ganeshkumar, Vimalkumar; Thavamani, Palanisami; Chen, Zuliang; Naidu, Ravi; Megharaj, Mallavarapu

    2016-07-01

    This study investigated an integrated and sustainable approach for iron nanoparticles synthesis using Chlorella sp. MM3 biomass produced from the remediation of brewery wastewater. The algal growth characteristics, biomass production, nutrient removal, and nanoparticle synthesis including its characterisation were studied to prove the above approach. The growth curve of Chlorella depicted lag and exponential phase characteristics during the first 4days in a brewery wastewater collected from a single batch of brewing process (single water sample) indicating the growth of algae in brewery wastewater. The pollutants such as total nitrogen, total phosphorus and total organic carbon in single water sample were completely utilised by Chlorella for its growth. The X-ray photoelectron spectroscopy spectra showed peaks at 706.56eV, 727.02eV, 289.84eV and 535.73eV which corresponded to the zero-valent iron, iron oxides, carbon and oxygen respectively, confirming the formation of iron nanoparticle capped with algal biomolecules. Scanning electron microscopy and particle size analysis confirmed the presence of spherical shaped iron nanoparticles of size ranging from 5 to 50nm. To our knowledge, this is the first report on nanoparticle synthesis using the biomass generated from phycoremediation of brewery wastewater.

  5. Nitrogen Starvation Induced Oxidative Stress in an Oil-Producing Green Alga Chlorella sorokiniana C3

    PubMed Central

    He, Chen-Liu; Wang, Qiang

    2013-01-01

    Microalgal lipid is one of the most promising feedstocks for biodiesel production. Chlorella appears to be a particularly good option, and nitrogen (N) starvation is an efficient environmental pressure used to increase lipid accumulation in Chlorella cells. The effects of N starvation of an oil-producing wild microalga, Chlorella sorokiniana C3, on lipid accumulation were investigated using thin layer chromatography (TLC), confocal laser scanning microscopy (CLSM) and flow cytometry (FCM). The results showed that N starvation resulted in lipid accumulation in C. sorokiniana C3 cells, oil droplet (OD) formation and significant lipid accumulation in cells were detected after 2 d and 8 d of N starvation, respectively. During OD formation, reduced photosynthetic rate, respiration rate and photochemistry efficiency accompanied by increased damage to PSII were observed, demonstrated by chlorophyll (Chl) fluorescence, 77K fluorescence and oxygen evolution tests. In the mean time the rate of cyclic electron transportation increased correspondingly to produce more ATP for triacylglycerols (TAGs) synthesis. And 0.5 d was found to be the turning point for the early stress response and acclimation of cells to N starvation. Increased level of membrane peroxidation was also observed during OD formation, and superoxide dismutase (SOD), peroxide dismutase (POD) and catalase (CAT) enzyme activity assays suggested impaired reactive oxygen species (ROS) scavenging ability. Significant neutral lipid accumulation was also observed by artificial oxidative stress induced by H2O2 treatment. These results suggested coupled neutral lipid accumulation and oxidative stress during N starvation in C. sorokiniana C3. PMID:23874918

  6. Boron bioremoval by a newly isolated Chlorella sp. and its stimulation by growth stimulators.

    PubMed

    Taştan, Burcu Ertit; Duygu, Ergin; Dönmez, Gönül

    2012-01-01

    It has been well documented that excess concentrations of boron (B) causes toxic effects on many of the environmental systems. Although Chlorella sp. has been studied to remove pollutants from water, its capacity to remove B has not been investigated yet. Boron removal levels of newly isolated Chlorella sp. were investigated in BG 11 media with stimulators as triacontanol (TRIA) and/or sodium bicarbonate (NaHCO(3)) and without them, to test if they could increase the removal efficiency by increasing biomass. The assays were performed to determine the effect of different medial compositions, B concentrations, pH and biomass concentrations onto removal efficiency. Boron removal was investigated at 5-10 mg/L range at pH 8 in different medial compositions and maximum removal yield was found as 32.95% at 5.45 mg/L B in media with TRIA and NaHCO(3). The effect of different pH values on the maximum removal yield was investigated at pH 5-9, and the optimum pH was found again 8. The interactive effect of biomass concentration and B removal yield was also investigated at 0.386-1.061 g wet weight/L biomass. The highest removal yield was found as 38.03% at the highest biomass range. This study highlights the importance of using new isolate Chlorella sp. as a new biomaterial for B removal process of waters containing B.

  7. Optimization of simultaneous biomass production and nutrient removal by mixotrophic Chlorella sp. using response surface methodology.

    PubMed

    Lee, Yu-Ru; Chen, Jen-Jeng

    2016-01-01

    The bioprospecting of potentially mixotrophic microalgae in a constructed wetland was conducted. A locally isolated microalga, Chlorella sp., was grown to determine the effect of temperature, aeration rate, and cultivation time on simultaneous biomass production and nutrient removal from piggery wastewater using central composite design (CCD). The most important variable for the biomass productivity of Chlorella sp. was aeration rate, while that for lipid content and nutrient removal efficiency was cultivation time. Total nitrogen (TN) and total phosphorus (TP) removal efficiencies were higher than that of chemical oxygen demand (COD) from piggery wastewater. The CCD results indicate that the highest biomass productivity (79.2 mg L(-1) d(-1)) and simultaneous nutrient removal efficiency (TN 80.9%, TP 99.2%, COD 74.5%) were obtained with a cultivation temperature of 25 °C, a cultivation time of 5 days, and an air aeration rate of 1.6 L L(-1) min(-1). Palmitic acid (C16:0) and linoleic acid (C18:2) were both abundant in Chlorella sp. cells under mixotrophic cultivation with piggery wastewater.

  8. Cultivation of Chlorella on brewery wastewater and nano-particle biosynthesis by its biomass.

    PubMed

    Subramaniyam, Vidhyasri; Subashchandrabose, Suresh Ramraj; Ganeshkumar, Vimalkumar; Thavamani, Palanisami; Chen, Zuliang; Naidu, Ravi; Megharaj, Mallavarapu

    2016-07-01

    This study investigated an integrated and sustainable approach for iron nanoparticles synthesis using Chlorella sp. MM3 biomass produced from the remediation of brewery wastewater. The algal growth characteristics, biomass production, nutrient removal, and nanoparticle synthesis including its characterisation were studied to prove the above approach. The growth curve of Chlorella depicted lag and exponential phase characteristics during the first 4days in a brewery wastewater collected from a single batch of brewing process (single water sample) indicating the growth of algae in brewery wastewater. The pollutants such as total nitrogen, total phosphorus and total organic carbon in single water sample were completely utilised by Chlorella for its growth. The X-ray photoelectron spectroscopy spectra showed peaks at 706.56eV, 727.02eV, 289.84eV and 535.73eV which corresponded to the zero-valent iron, iron oxides, carbon and oxygen respectively, confirming the formation of iron nanoparticle capped with algal biomolecules. Scanning electron microscopy and particle size analysis confirmed the presence of spherical shaped iron nanoparticles of size ranging from 5 to 50nm. To our knowledge, this is the first report on nanoparticle synthesis using the biomass generated from phycoremediation of brewery wastewater. PMID:27060245

  9. Culture of a high-chlorophyll-producing and halotolerant Chlorella vulgaris.

    PubMed

    Nakanishi, Koichi; Deuchi, Keiji

    2014-05-01

    In order to increase the value of freshwater algae as raw ingredients for health foods and feed for seawater-based farmed fish, we sought to breed high-chlorophyll halotolerant Chlorella with the objective of generating strains with both high chlorophyll concentrations (≥ 5%) and halotolerance (up to 1% NaCl). We used the Chlorella vulgaris K strain in our research institute culture collection and induced mutations with UV irradiation and acriflavine which is known to effect mutations of mitochondrial DNA that are associated with chlorophyll production. Screenings were conducted on seawater-based "For Chlorella spp." (FC) agar medium, and dark-green-colored colonies were visually selected by macroscopic inspection. We obtained a high-chlorophyll halotolerant strain (designated C. vulgaris M-207A7) that had a chlorophyll concentration of 6.7% (d.m.), a level at least three-fold higher than that of K strain. This isolate also exhibited a greater survival rate in seawater that of K strain.

  10. Optimization of simultaneous biomass production and nutrient removal by mixotrophic Chlorella sp. using response surface methodology.

    PubMed

    Lee, Yu-Ru; Chen, Jen-Jeng

    2016-01-01

    The bioprospecting of potentially mixotrophic microalgae in a constructed wetland was conducted. A locally isolated microalga, Chlorella sp., was grown to determine the effect of temperature, aeration rate, and cultivation time on simultaneous biomass production and nutrient removal from piggery wastewater using central composite design (CCD). The most important variable for the biomass productivity of Chlorella sp. was aeration rate, while that for lipid content and nutrient removal efficiency was cultivation time. Total nitrogen (TN) and total phosphorus (TP) removal efficiencies were higher than that of chemical oxygen demand (COD) from piggery wastewater. The CCD results indicate that the highest biomass productivity (79.2 mg L(-1) d(-1)) and simultaneous nutrient removal efficiency (TN 80.9%, TP 99.2%, COD 74.5%) were obtained with a cultivation temperature of 25 °C, a cultivation time of 5 days, and an air aeration rate of 1.6 L L(-1) min(-1). Palmitic acid (C16:0) and linoleic acid (C18:2) were both abundant in Chlorella sp. cells under mixotrophic cultivation with piggery wastewater. PMID:27054723

  11. Nitrogen and phosphorus removal from municipal wastewater by the green alga Chlorella sp.

    PubMed

    Wang, Changfu; Yu, Xiaoqing; Lv, Hong; Yang, Jun

    2013-04-01

    The potential of microalgae as a source of renewable energy based on wastewater has received increasing interest worldwide in recent decades. A freshwater microalga Chlorella sp. was investigated for its ability to remove both nitrogen and phosphorus from influent and effluent wastewaters which were diluted in four different proportions (namely, 100%, 75%, 50% and 25%). Chlorella sp. grew fastest under 50% influent and effluent wastewaters culture conditions, and showed an maximum cell density (4.25 x 10(9) ind 1(-1) for influent wastewater and 3.54 x 109 ind l(-1) for effluent wastewater), indicating the levels of nitrogen and phosphorus greatly influenced algal growth. High removal efficiency for total nitrogen (17.04-58.85%) and total phosphorus (62.43-97.08%) was achieved. Further, more than 83% NH4-N in 75%, 50%, 25% influent wastewater, 88% NOx-N in effluent wastewater and 90% PO4-P in all treatments were eliminated after 24 days of incubation. Chlorella sp. grew well when PO4-P concentration was very low, indicating that this might be not the limiting factor to algal growth. Our results suggest the potential importance of integrating nutrient removal from wastewater by microalgae cultivation as biofuel production feedstock.

  12. Bioremoval of the azo dye Congo Red by the microalga Chlorella vulgaris.

    PubMed

    Hernández-Zamora, Miriam; Cristiani-Urbina, Eliseo; Martínez-Jerónimo, Fernando; Perales-Vela, Hugo Virgilio; Ponce-Noyola, Teresa; Montes-Horcasitas, María del Carmen; Cañizares-Villanueva, Rosa Olivia

    2015-07-01

    Discharge of dye-containing wastewater by the textile industry can adversely affect aquatic ecosystems and human health. Bioremoval is an alternative to industrial processes for detoxifying water contaminated with dyes. In this work, active and inactive biomass of the microalga Chlorella vulgaris was assayed for the ability to remove Congo Red (CR) dye from aqueous solutions. Through biosorption and biodegradation processes, Chlorella vulgaris was able to remove 83 and 58 % of dye at concentrations of 5 and 25 mg L(-1), respectively. The maximum adsorption capacity at equilibrium was 200 mg g(-1). The Langmuir model best described the experimental equilibrium data. The acute toxicity test (48 h) with two species of cladocerans indicated that the toxicity of the dye in the effluent was significantly decreased compared to the initial concentrations in the influent. Daphnia magna was the species less sensitive to dye (EC50 = 17.0 mg L(-1)), followed by Ceriodaphnia dubia (EC50 = 3.32 mg L(-1)). These results show that Chlorella vulgaris significantly reduced the dye concentration and toxicity. Therefore, this method may be a viable option for the treatment of this type of effluent.

  13. Bioremoval of the azo dye Congo Red by the microalga Chlorella vulgaris.

    PubMed

    Hernández-Zamora, Miriam; Cristiani-Urbina, Eliseo; Martínez-Jerónimo, Fernando; Perales-Vela, Hugo Virgilio; Ponce-Noyola, Teresa; Montes-Horcasitas, María del Carmen; Cañizares-Villanueva, Rosa Olivia

    2015-07-01

    Discharge of dye-containing wastewater by the textile industry can adversely affect aquatic ecosystems and human health. Bioremoval is an alternative to industrial processes for detoxifying water contaminated with dyes. In this work, active and inactive biomass of the microalga Chlorella vulgaris was assayed for the ability to remove Congo Red (CR) dye from aqueous solutions. Through biosorption and biodegradation processes, Chlorella vulgaris was able to remove 83 and 58 % of dye at concentrations of 5 and 25 mg L(-1), respectively. The maximum adsorption capacity at equilibrium was 200 mg g(-1). The Langmuir model best described the experimental equilibrium data. The acute toxicity test (48 h) with two species of cladocerans indicated that the toxicity of the dye in the effluent was significantly decreased compared to the initial concentrations in the influent. Daphnia magna was the species less sensitive to dye (EC50 = 17.0 mg L(-1)), followed by Ceriodaphnia dubia (EC50 = 3.32 mg L(-1)). These results show that Chlorella vulgaris significantly reduced the dye concentration and toxicity. Therefore, this method may be a viable option for the treatment of this type of effluent. PMID:25772869

  14. Initial Events Associated with Virus PBCV-1 Infection of Chlorella NC64A

    PubMed Central

    Thiel, Gerhard; Moroni, Anna; Dunigan, David; Van Etten, James L.

    2010-01-01

    Chlorella viruses (or chloroviruses) are very large, plaque-forming viruses. The viruses are multilayered structures containing a large double-stranded DNA genome, a lipid bilayered membrane, and an outer icosahedral capsid shell. The viruses replicate in certain isolates of the coccal green alga, Chlorella. Sequence analysis of the 330-kbp genome of Paramecium bursaria Chlorella virus 1 (PBCV-1), the prototype of the virus family Phycodnaviridae, reveals <365 protein-encoding genes and 11 tRNA genes. Products of about 40% of these genes resemble proteins of known function, including many that are unexpected for a virus. Among these is a virus-encoded protein, called Kcv, which forms a functional K+ channel. This chapter focuses on the initial steps in virus infection and provides a plausible role for the function of the viral K+ channel in lowering the turgor pressure of the host. This step appears to be a prerequisite for delivery of the viral genome into the host. PMID:21152366

  15. Enzymatic cell wall degradation of Chlorella vulgaris and other microalgae for biofuels production.

    PubMed

    Gerken, Henri G; Donohoe, Bryon; Knoshaug, Eric P

    2013-01-01

    Cell walls of microalgae consist of a polysaccharide and glycoprotein matrix providing the cells with a formidable defense against its environment. We characterized enzymes that can digest the cell wall and weaken this defense for the purpose of protoplasting or lipid extraction. A growth inhibition screen demonstrated that chitinase, lysozyme, pectinase, sulfatase, β-glucuronidase, and laminarinase had the broadest effect across the various Chlorella strains tested and also inhibited Nannochloropsis and Nannochloris strains. Chlorella is typically most sensitive to chitinases and lysozymes, both enzymes that degrade polymers containing N-acetylglucosamine. Using a fluorescent DNA stain, we developed rapid methodology to quantify changes in permeability in response to enzyme digestion and found that treatment with lysozyme in conjunction with other enzymes has a drastic effect on cell permeability. Transmission electron microscopy of enzymatically treated Chlorella vulgaris indicates that lysozyme degrades the outer surface of the cell wall and removes hair-like fibers protruding from the surface, which differs from the activity of chitinase. This action on the outer surface of the cell causes visible protuberances on the cell surface and presumably leads to the increased settling rate when cells are treated with lysozyme. We demonstrate radical ultrastructural changes to the cell wall in response to treatment with various enzyme combinations which, in some cases, causes a greater than twofold increase in the thickness of the cell wall. The enzymes characterized in this study should prove useful in the engineering and extraction of oils from microalgae.

  16. Nitrogen and phosphorus removal from municipal wastewater by the green alga Chlorella sp.

    PubMed

    Wang, Changfu; Yu, Xiaoqing; Lv, Hong; Yang, Jun

    2013-04-01

    The potential of microalgae as a source of renewable energy based on wastewater has received increasing interest worldwide in recent decades. A freshwater microalga Chlorella sp. was investigated for its ability to remove both nitrogen and phosphorus from influent and effluent wastewaters which were diluted in four different proportions (namely, 100%, 75%, 50% and 25%). Chlorella sp. grew fastest under 50% influent and effluent wastewaters culture conditions, and showed an maximum cell density (4.25 x 10(9) ind 1(-1) for influent wastewater and 3.54 x 109 ind l(-1) for effluent wastewater), indicating the levels of nitrogen and phosphorus greatly influenced algal growth. High removal efficiency for total nitrogen (17.04-58.85%) and total phosphorus (62.43-97.08%) was achieved. Further, more than 83% NH4-N in 75%, 50%, 25% influent wastewater, 88% NOx-N in effluent wastewater and 90% PO4-P in all treatments were eliminated after 24 days of incubation. Chlorella sp. grew well when PO4-P concentration was very low, indicating that this might be not the limiting factor to algal growth. Our results suggest the potential importance of integrating nutrient removal from wastewater by microalgae cultivation as biofuel production feedstock. PMID:24620613

  17. A new inducible expression system in a transformed green alga, Chlorella vulgaris.

    PubMed

    Niu, Y F; Zhang, M H; Xie, W H; Li, J N; Gao, Y F; Yang, W D; Liu, J S; Li, H Y

    2011-01-01

    Genetic transformation is useful for basic research and applied biotechnology. However, genetic transformation of microalgae is usually quite difficult due to the technical limitations of existing methods. We cloned the promoter and terminator of the nitrate reductase gene from the microalga Phaeodactylum tricornutum and used them for optimization of a transformation system of the microalga Chlorella vulgaris. This species has been used for food production and is a promising candidate as a bioreactor for large-scale production of value-added proteins. A construct was made containing the CAT (chloramphenicol acetyltransferase) reporter gene driven by the nitrate reductase promoter. This construct was transferred into the C. vulgaris genome by electroporation. Expression of CAT in transgenic Chlorella conferred resistance to the antibiotic chloramphenicol and enabled growth in selective media. Overall efficiency for the transformation was estimated to be approximately 0.03%, which is relatively high compared with other available Chlorella transformation systems. Expression of CAT was induced in the presence of nitrate and inhibited in the presence of ammonium as a sole nitrogen source. This study presented an inducible recombinant gene expression system, also providing more gene regulation elements with potential for biotechnological applications.

  18. Enhanced accumulation of starch and total carbohydrates in alginate-immobilized Chlorella spp. induced by Azospirillum brasilense: I. Autotrophic conditions.

    PubMed

    Choix, Francisco J; de-Bashan, Luz E; Bashan, Yoav

    2012-10-10

    The effect of the microalgae-growth promoting bacterium Azospirillum brasilense on accumulation of total carbohydrates and starch in two species of Chlorella (Chlorella vulgaris and Chlorella sorokiniana), when the bacterium and each microalga were jointly immobilized in alginate beads was studied under autotrophic conditions for 144 h in synthetic medium. The interaction of the bacterium with the microalgae enhanced accumulation of total carbohydrate and starch. Cells of Chlorella accumulated the highest amounts of carbohydrate after incubation for 24h. Yet, this did not coincide with the highest affinity and volumetric productivity measured in these cultures. However, after incubation for 72 h, mainly in jointly immobilized treatments of both microalgae species, the cultures reached their highest total carbohydrate content (mainly as starch) and also the highest affinity and volumetric productivity. These results demonstrate the potential of A. brasilense to affect carbohydrates and starch accumulation in Chlorella spp. when both microorganisms are co-cultured, which can be an important tool for applications of microalgae.

  19. Chlorella Protein Hydrolysate Attenuates Glucose Metabolic Disorder and Fatty Liver in High-fat Diet-induced Obese Mice.

    PubMed

    Noguchi, Naoto; Yanagita, Teruyoshi; Rahman, Shaikh Mizanoor; Ando, Yotaro

    2016-07-01

    Chlorella (Parachlorella beijerinckii) powder is reported to show a preventive effect against metabolic syndromes such as arteriosclerosis, hyperlipidemia, and hypertension. Approximately 60% of the chlorella content is protein. In order to understand the role of chlorella protein, we prepared a chlorella protein hydrolysate (CPH) by protease treatment. Male C57BL/6 mice were divided into three groups: a normal diet group, high-fat diet (HFD) group, and high-fat diet supplemented with CPH (HFD+CPH) group. The CPH administration improved glucose intolerance, insulin sensitivity, and adipose tissue hypertrophy in the high-fat diet-fed mice. In addition, the HFD+CPH group had significantly decreased liver total cholesterol and triglyceride levels compared with those in the HFD group. Furthermore, the HFD+CPH group had a decreased level of monocyte chemotactic protein-1 (MCP-1) in serum and a lower MCP-1 mRNA expression level in adipose tissue compared with the HFD group. The present study suggests that chlorella protein hydrolysate can prevent a high-fat diet-induced glucose disorder and fatty liver by inhibiting adipocyte hypertrophy and reducing the MCP-1 protein and gene expression. PMID:27321121

  20. Treatment of African catfish, Clarias gariepinus wastewater utilizing phytoremediation of microalgae, Chlorella sp. with Aspergillus niger bio-harvesting.

    PubMed

    Nasir, Nurfarahana Mohd; Bakar, Nur Syuhada Abu; Lananan, Fathurrahman; Abdul Hamid, Siti Hajar; Lam, Su Shiung; Jusoh, Ahmad

    2015-08-01

    This study focuses on the evaluation of the performance of Chlorella sp. in removing nutrient in aquaculture wastewater and its correlation with the kinetic growth of Chlorella sp. The treatment was applied with various Chlorella sp. inoculation dosage ranging from 0% to 60% (v/v) of wastewater. The optimum inoculation dosage was recorded at 30% (v/v) with effluent concentration of ammonia and orthophosphate recording at 0.012mgL(-1) and 0.647mgL(-1), respectively on Day 11. The optimum dosage for bio-flocculation process was obtained at 30mgL(-1) of Aspergillus niger with a harvesting efficiency of 97%. This type of development of phytoremediation with continuous bio-harvesting could promote the use of sustainable green technology for effective wastewater treatment.

  1. Hydrolysis of Chlorella biomass for fermentable sugars in the presence of HCl and MgCl2.

    PubMed

    Zhou, Na; Zhang, Yimin; Wu, Xiaobin; Gong, Xiaowu; Wang, Qinhong

    2011-11-01

    When Chlorella biomass was hydrolyzed in the presence of 2% HCl and 2.5% MgCl(2), a sugar concentration of nearly 12%, and a sugar recovery of about 83% was obtained. Fermentation experiments demonstrated that glucose in the Chlorella biomass hydrolysates was converted into ethanol by Saccharomyces cerevisiae with a yield of 0.47 g g(-1), which is 91% of the theoretical yield. This chemical hydrolysis approach is thus a novel route for the hydrolysis of biomass to generate fermentable sugars.

  2. Sulfur Deprivation Results in Oxidative Perturbation in Chlorella sorokiniana (211/8k).

    PubMed

    Salbitani, Giovanna; Vona, Vincenza; Bottone, Claudia; Petriccione, Milena; Carfagna, Simona

    2015-05-01

    Sulfur deficiency in plant cells has not been considered as a potential abiotic factor that can induce oxidative stress. We studied the antioxidant defense system of Chlorella sorokiniana cultured under sulfur (S) deficiency, imposed for a maximum period of 24 h, to evaluate the effect of an S shortage on oxidative stress. S deprivation induced an immediate (30 min) but transient increase in the intracellular H2O2 content, which suggests that S limitation can lead to a temporary redox disturbance. After 24 h, S deficiency in Chlorella cells decreased the glutathione content to <10% of the value measured in cells that were not subjected to S deprivation. Consequently, we assumed that the cellular antioxidative mechanisms could be altered by a decrease in the total glutathione content. The total ascorbate pool increased within 2 h after the initiation of S depletion, and remained high until 6 h; however, ascorbate regeneration was inhibited under limited S conditions, indicated by a significant decrease in the ascorbate/dehydroascorbate (AsA/DHA) ratios. Furthermore, ascorbate peroxidase (APX) and superoxide dismutase (SOD) were activated under S deficiency, but we assumed that these enzymes were involved in maintaining the cellular H2O2 balance for at least 4 h after the initiation of S starvation. We concluded that S deprivation triggers redox changes and induces antioxidant enzyme activities in Chlorella cells. The accumulation of total ascorbate, changes in the reduced glutathione/oxidized glutathione (GSH/GSSG) ratios and an increase in the activity of SOD and APX enzymes indicate that oxidative perturbation occurs during S deprivation.

  3. Suppression Subtractive Hybridization Reveals Transcript Profiling of Chlorella under Heterotrophy to Photoautotrophy Transition

    PubMed Central

    Huang, Jianke; Wang, Weiliang; Yin, Weibo; Hu, Zanmin; Li, Yuanguang

    2012-01-01

    Background Microalgae have been extensively investigated and exploited because of their competitive nutritive bioproducts and biofuel production ability. Chlorella are green algae that can grow well heterotrophically and photoautotrophically. Previous studies proved that shifting from heterotrophy to photoautotrophy in light-induced environments causes photooxidative damage as well as distinct physiologic features that lead to dynamic changes in Chlorella intracellular components, which have great potential in algal health food and biofuel production. However, the molecular mechanisms underlying the trophic transition remain unclear. Methodology/Principal Findings In this study, suppression subtractive hybridization strategy was employed to screen and characterize genes that are differentially expressed in response to the light-induced shift from heterotrophy to photoautotrophy. Expressed sequence tags (ESTs) were obtained from 770 and 803 randomly selected clones among the forward and reverse libraries, respectively. Sequence analysis identified 544 unique genes in the two libraries. The functional annotation of the assembled unigenes demonstrated that 164 (63.1%) from the forward library and 62 (21.8%) from the reverse showed significant similarities with the sequences in the NCBI non-redundant database. The time-course expression patterns of 38 selected differentially expressed genes further confirmed their responsiveness to a diverse trophic status. The majority of the genes enriched in the subtracted libraries were associated with energy metabolism, amino acid metabolism, protein synthesis, carbohydrate metabolism, and stress defense. Conclusions/Significance The data presented here offer the first insights into the molecular foundation underlying the diverse microalgal trophic niche. In addition, the results can be used as a reference for unraveling candidate genes associated with the transition of Chlorella from heterotrophy to photoautotrophy, which holds

  4. Using oxidized liquid and solid human waste as nutrients for Chlorella vulgaris and cyanobacterium Oscillatoria deflexa

    NASA Astrophysics Data System (ADS)

    Trifonov, Sergey V.; Kalacheva, Galina; Tirranen, Lyalya; Gribovskaya, Iliada

    At stationary terrestrial and space stations with closed and partially closed substance exchange not only plants, but also algae can regenerate atmosphere. Their biomass can be used for feeding Daphnia and Moina species, which, in their turn, serve as food for fish. In addition, it is possible to use algae for production of biological fuel. We suggested two methods of human waste mineralization: dry (evaporation with subsequent incineration in a muffle furnace) and wet (oxidation in a reactor using hydrogen peroxide). The research task was to prepare nutrient media for green alga Chlorella vulgaris and cyanobacterium Oscillatoria deflexa using liquid human waste mineralized by dry method, and to prepare media for chlorella on the basis of 1) liquid and 2) liquid and solid human waste mineralized by wet method. The algae were grown in batch culture in a climate chamber with the following parameters: illumination 7 klx, temperature 27-30 (°) C, culture density 1-2 g/l of dry weight. The control for chlorella was Tamiya medium, pH-5, and for oscillstoria — Zarrouk medium, pH-10. Maximum permissible concentrations of NaCl, Cl, urea (NH _{2}) _{2}CO, and native urine were established for algae. Missing ingredients (such as salts and acids) for experimental nutrient media were determined: their addition made it possible to obtain the biomass production not less than that in the control. The estimation was given of the mineral and biochemical composition of algae grown on experimental media. Microbiological test revealed absence of foreign microbial flora in experimental cultures.

  5. Biodiesel Production from Chlorella protothecoides Oil by Microwave-Assisted Transesterification

    PubMed Central

    Gülyurt, Mustafa Ömer; Özçimen, Didem; İnan, Benan

    2016-01-01

    In this study, biodiesel production from microalgal oil by microwave-assisted transesterification was carried out to investigate its efficiency. Transesterification reactions were performed by using Chlorella protothecoides oil as feedstock, methanol, and potassium hydroxide as the catalyst. Methanol:oil ratio, reaction time and catalyst:oil ratio were investigated as process parameters affected methyl ester yield. 9:1 methanol/oil molar ratio, 1.5% KOH catalyst/oil ratio and 10 min were optimum values for the highest fatty acid methyl ester yield. PMID:27110772

  6. Nitric oxide inhibitory activity of monogalactosylmonoacylglycerols from a freshwater microalgae Chlorella sorokiniana.

    PubMed

    Banskota, Arjun H; Stefanova, Roumiana; Gallant, Pamela; Osborne, Jane A; Melanson, Ronald; O'Leary, Stephen J B

    2013-01-01

    Chemical investigation of the freshwater microalgae Chlorella sorokiniana led to the isolation of a new monogalactosylmonoacylglycerol, namely, (2S)-1-O-(7Z,10Z-hexadecadienoyl)-3-O-β-D-galactopyranosylglycerol (1) together with a known glycolipid (2S)-1-O-(7Z,10Z,13Z-hexadecatrienoyl)-3-O-β-D-galactopyranosylglycerol (2). Both monogalactosylmonoacylglycerols showed dose-dependent nitric oxide (NO) inhibitory activity against lipopolysaccharide-induced NO production in RAW264.7 macrophage cells suggesting their possible use as anti-inflammatory agents. PMID:22703524

  7. A Novel Treatment Protects Chlorella at Commercial Scale from the Predatory Bacterium Vampirovibrio chlorellavorus.

    PubMed

    Ganuza, Eneko; Sellers, Charles E; Bennett, Braden W; Lyons, Eric M; Carney, Laura T

    2016-01-01

    The predatory bacterium, Vampirovibrio chlorellavorus, can destroy a Chlorella culture in just a few days, rendering an otherwise robust algal crop into a discolored suspension of empty cell walls. Chlorella is used as a benchmark for open pond cultivation due to its fast growth. In nature, V. chlorellavorus plays an ecological role by controlling this widespread terrestrial and freshwater microalga, but it can have a devastating effect when it attacks large commercial ponds. We discovered that V. chlorellavorus was associated with the collapse of four pilot commercial-scale (130,000 L volume) open-pond reactors. Routine microscopy revealed the distinctive pattern of V. chlorellavorus attachment to the algal cells, followed by algal cell clumping, culture discoloration and ultimately, growth decline. The "crash" of the algal culture coincided with increasing proportions of 16s rRNA sequencing reads assigned to V. chlorellavorus. We designed a qPCR assay to predict an impending culture crash and developed a novel treatment to control the bacterium. We found that (1) Chlorella growth was not affected by a 15 min exposure to pH 3.5 in the presence of 0.5 g/L acetate, when titrated with hydrochloric acid and (2) this treatment had a bactericidal effect on the culture (2-log decrease in aerobic counts). Therefore, when qPCR results indicated a rise in V. chlorellavorus amplicons, we found that the pH-shock treatment prevented the culture crash and doubled the productive longevity of the culture. Furthermore, the treatment could be repeatedly applied to the same culture, at the beginning of at least two sequential batch cycles. In this case, the treatment was applied preventively, further increasing the longevity of the open pond culture. In summary, the treatment reversed the infection of V. chlorellavorus as confirmed by observations of bacterial attachment to Chlorella cells and by detection of V. chlorellavorus by 16s rRNA sequencing and qPCR assay. The p

  8. Anti-inflammatory and immunomodulatory activities of polysaccharide from Chlorella stigmatophora and Phaeodactylum tricornutum.

    PubMed

    Guzmán, S; Gato, A; Lamela, M; Freire-Garabal, M; Calleja, J M

    2003-06-01

    Crude polysaccharide extracts were obtained from aqueous extracts of the microalgae Chlorella stigmatophora and Phaeodactylum tricornutum. The crude extracts were fractionated by ion-exchange chromatography on DEAE-cellulose columns. The molecular weights of the polysaccharides in each fraction were estimated by gel filtration on Sephacryl columns. The crude polysaccharide extracts of both microalgae showed anti-inflammatory activity in the carrageenan-induced paw edema test. In assays of effects on the delayed hyper-sensitivity response, and on phagocytic activity assayed in vivo and in vitro, the C. stigmatophora extract showed immunosuppressant effects, while the P. tricornutum extract showed immunostimulatory effects. PMID:12820237

  9. Adaptability of growth and nutrient uptake potential of Chlorella sorokiniana with variable nutrient loading.

    PubMed

    Shriwastav, Amritanshu; Gupta, Sanjay Kumar; Ansari, Faiz Ahmad; Rawat, Ismail; Bux, Faizal

    2014-12-01

    Chlorella sorokiniana can sustain growth in conditions hostile to other species, and possesses good nutrient removal and lipid accumulation potentials. However, the effects of variable nutrient levels (N and P) in wastewaters on growth, productivity, and nutrient uptake by C. sorokiniana have not been studied in detail. This study demonstrates the ability of this alga to sustain uniform growth and productivity, while regulating the relative nutrient uptake in accordance to their availability in the bulk medium. These results highlight the potential of C. sorokiniana as a suitable candidate for fulfilling the coupled objectives of nutrient removal and biomass production for bio-fuel with wastewaters having great variability in nutrient levels.

  10. Complete genome sequence of chloroplast DNA (cpDNA) of Chlorella sorokiniana.

    PubMed

    Orsini, Massimiliano; Cusano, Roberto; Costelli, Cristina; Malavasi, Veronica; Concas, Alessandro; Angius, Andrea; Cao, Giacomo

    2016-01-01

    The complete chloroplast genome sequence of Chlorella sorokiniana strain (SAG 111-8 k) is presented in this study. The genome consists of circular chromosomes of 109,811 bp, which encode a total of 109 genes, including 74 proteins, 3 rRNAs and 31 tRNAs. Moreover, introns are not detected and all genes are present in single copy. The overall AT contents of the C. sorokiniana cpDNA is 65.9%, the coding sequence is 59.1% and a large inverted repeat (IR) is not observed.

  11. The mutation process in a chlorella population under the combined action of radionuclides and chemical mutagens

    SciTech Connect

    Ptitsyna, S.N.; Sergeeva, S.A.; Shevchenko, V.A.; Shvobene, R.Y.

    1985-09-01

    This paper investigates the dynamics of the mutation process under the combined chronic action of radionuclides (/sup 144/Ce, /sup 90/Sr) and inhibitors of repair, acriflavine and caffeine, as well as under the joint action of ethyleneimine and acriflavine, in a Chlorella population. It is shown that the modifying effect of acriflavine is more pronounced under the action of /sup 144/Ce, which is evidently due to its stronger genetic effect, in comparison with /sup 90/Sr. Experiments with inhibitors confirm the participation of the repair systems in the establishment of the visible picture of the mutation process induced by radionuclides and by ethyleneimine (EI).

  12. A Novel Treatment Protects Chlorella at Commercial Scale from the Predatory Bacterium Vampirovibrio chlorellavorus.

    PubMed

    Ganuza, Eneko; Sellers, Charles E; Bennett, Braden W; Lyons, Eric M; Carney, Laura T

    2016-01-01

    The predatory bacterium, Vampirovibrio chlorellavorus, can destroy a Chlorella culture in just a few days, rendering an otherwise robust algal crop into a discolored suspension of empty cell walls. Chlorella is used as a benchmark for open pond cultivation due to its fast growth. In nature, V. chlorellavorus plays an ecological role by controlling this widespread terrestrial and freshwater microalga, but it can have a devastating effect when it attacks large commercial ponds. We discovered that V. chlorellavorus was associated with the collapse of four pilot commercial-scale (130,000 L volume) open-pond reactors. Routine microscopy revealed the distinctive pattern of V. chlorellavorus attachment to the algal cells, followed by algal cell clumping, culture discoloration and ultimately, growth decline. The "crash" of the algal culture coincided with increasing proportions of 16s rRNA sequencing reads assigned to V. chlorellavorus. We designed a qPCR assay to predict an impending culture crash and developed a novel treatment to control the bacterium. We found that (1) Chlorella growth was not affected by a 15 min exposure to pH 3.5 in the presence of 0.5 g/L acetate, when titrated with hydrochloric acid and (2) this treatment had a bactericidal effect on the culture (2-log decrease in aerobic counts). Therefore, when qPCR results indicated a rise in V. chlorellavorus amplicons, we found that the pH-shock treatment prevented the culture crash and doubled the productive longevity of the culture. Furthermore, the treatment could be repeatedly applied to the same culture, at the beginning of at least two sequential batch cycles. In this case, the treatment was applied preventively, further increasing the longevity of the open pond culture. In summary, the treatment reversed the infection of V. chlorellavorus as confirmed by observations of bacterial attachment to Chlorella cells and by detection of V. chlorellavorus by 16s rRNA sequencing and qPCR assay. The p

  13. A Novel Treatment Protects Chlorella at Commercial Scale from the Predatory Bacterium Vampirovibrio chlorellavorus

    PubMed Central

    Ganuza, Eneko; Sellers, Charles E.; Bennett, Braden W.; Lyons, Eric M.; Carney, Laura T.

    2016-01-01

    The predatory bacterium, Vampirovibrio chlorellavorus, can destroy a Chlorella culture in just a few days, rendering an otherwise robust algal crop into a discolored suspension of empty cell walls. Chlorella is used as a benchmark for open pond cultivation due to its fast growth. In nature, V. chlorellavorus plays an ecological role by controlling this widespread terrestrial and freshwater microalga, but it can have a devastating effect when it attacks large commercial ponds. We discovered that V. chlorellavorus was associated with the collapse of four pilot commercial-scale (130,000 L volume) open-pond reactors. Routine microscopy revealed the distinctive pattern of V. chlorellavorus attachment to the algal cells, followed by algal cell clumping, culture discoloration and ultimately, growth decline. The “crash” of the algal culture coincided with increasing proportions of 16s rRNA sequencing reads assigned to V. chlorellavorus. We designed a qPCR assay to predict an impending culture crash and developed a novel treatment to control the bacterium. We found that (1) Chlorella growth was not affected by a 15 min exposure to pH 3.5 in the presence of 0.5 g/L acetate, when titrated with hydrochloric acid and (2) this treatment had a bactericidal effect on the culture (2-log decrease in aerobic counts). Therefore, when qPCR results indicated a rise in V. chlorellavorus amplicons, we found that the pH-shock treatment prevented the culture crash and doubled the productive longevity of the culture. Furthermore, the treatment could be repeatedly applied to the same culture, at the beginning of at least two sequential batch cycles. In this case, the treatment was applied preventively, further increasing the longevity of the open pond culture. In summary, the treatment reversed the infection of V. chlorellavorus as confirmed by observations of bacterial attachment to Chlorella cells and by detection of V. chlorellavorus by 16s rRNA sequencing and qPCR assay. The p

  14. Administration of Thiamine and Thiochrome Enhanced Reproduction of Chlorella, Drosophila melanogaster, and Danio.

    PubMed

    Petrov, Sergiy Anatoliyovich; Zamorov, Veniamin Veniaminovich; Ustyanskaya, Olga Volodymyrivna; Budnyak, Olexandr Kostyantynovich; Chernadchuk, Snizhana Sergiivna; Andrievskiy, Olexandr Michaelovich; Semyonova, Olga Olexandrivna; Karavanskiy, Yuriy Viktorovych; Yakimenko, Viktoriya Evgenievna; Kravchuk, Ilona Olegivna

    2016-01-01

    Thiochrome, a natural metabolite of thiamine, has scarcely attracted the attention of researchers, since many of them considered it to be a biologically inactive substance. We examined a possible effect of thiochrome upon the reproduction of the organisms of Chlorella, Drosophila, and Danio. We added thiamine or thiochrome to the culture medium or to the aquaria. Our data showed that the number of cells and organisms were increased in the presence of thiamine and thiochrome. We suggest possible effect(s) of thiamine and thiochrome on the reproduction of these organisms.

  15. Synthesis and degradation of nitrate reductase during the cell cycle of Chlorella sorokiniana

    NASA Technical Reports Server (NTRS)

    Velasco, P. J.; Tischner, R.; Huffaker, R. C.; Whitaker, J. R.

    1989-01-01

    Studies on the diurnal variations of nitrate reductase (NR) activity during the life cycle of synchronized Chlorella sorokiniana cells grown with a 7:5 light-dark cycle showed that the NADH:NR activity, as well as the NR partial activities NADH:cytochrome c reductase and reduced methyl viologen:NR, closely paralleled the appearance and disappearance of NR protein as shown by sodium dodecyl sulfate gel electrophoresis and immunoblots. Results of pulse-labeling experiments with [35S]methionine further confirmed that diurnal variations of the enzyme activities can be entirely accounted for by the concomitant synthesis and degradation of the NR protein.

  16. Chlorella Induces Stomatal Closure via NADPH Oxidase-Dependent ROS Production and Its Effects on Instantaneous Water Use Efficiency in Vicia faba

    PubMed Central

    Li, Yan; Xu, Shan-Shan; Gao, Jing; Pan, Sha; Wang, Gen-Xuan

    2014-01-01

    Reactive oxygen species (ROS) have been established to participate in stomatal closure induced by live microbes and microbe-associated molecular patterns (MAMPs). Chlorella as a beneficial microorganism can be expected to trigger stomatal closure via ROS production. Here, we reported that Chlorella induced stomatal closure in a dose-and time-dependent manner in epidermal peels of Vicia faba. Using pharmacological methods in this work, we found that the Chlorella-induced stomatal closure was almost completely abolished by a hydrogen peroxide (H2O2) scavenger, catalase (CAT), significantly suppressed by an NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI), and slightly affected by a peroxidase inhibitor, salicylhydroxamic acid (SHAM), suggesting that ROS production involved in Chlorella-induced stomatal closure is mainly mediated by DPI-sensitive NADPH oxidase. Additionally, Exogenous application of optimal concentrations of Chlorella suspension improved instantaneous water use efficiency (WUEi) in Vicia faba via a reduction in leaf transpiration rate (E) without a parallel reduction in net photosynthetic rate (Pn) assessed by gas-exchange measurements. The chlorophyll fluorescence and content analysis further demonstrated that short-term use of Chlorella did not influence plant photosynthetic reactions center. These results preliminarily reveal that Chlorella can trigger stomatal closure via NADPH oxidase-dependent ROS production in epidermal strips and improve WUEi in leave levels. PMID:24687099

  17. The Chlorella variabilis NC64A Genome Reveals Adaptation to Photosymbiosis, Coevolution with Viruses, and Cryptic Sex[C][W

    PubMed Central

    Blanc, Guillaume; Duncan, Garry; Agarkova, Irina; Borodovsky, Mark; Gurnon, James; Kuo, Alan; Lindquist, Erika; Lucas, Susan; Pangilinan, Jasmyn; Polle, Juergen; Salamov, Asaf; Terry, Astrid; Yamada, Takashi; Dunigan, David D.; Grigoriev, Igor V.; Claverie, Jean-Michel; Van Etten, James L.

    2010-01-01

    Chlorella variabilis NC64A, a unicellular photosynthetic green alga (Trebouxiophyceae), is an intracellular photobiont of Paramecium bursaria and a model system for studying virus/algal interactions. We sequenced its 46-Mb nuclear genome, revealing an expansion of protein families that could have participated in adaptation to symbiosis. NC64A exhibits variations in GC content across its genome that correlate with global expression level, average intron size, and codon usage bias. Although Chlorella species have been assumed to be asexual and nonmotile, the NC64A genome encodes all the known meiosis-specific proteins and a subset of proteins found in flagella. We hypothesize that Chlorella might have retained a flagella-derived structure that could be involved in sexual reproduction. Furthermore, a survey of phytohormone pathways in chlorophyte algae identified algal orthologs of Arabidopsis thaliana genes involved in hormone biosynthesis and signaling, suggesting that these functions were established prior to the evolution of land plants. We show that the ability of Chlorella to produce chitinous cell walls likely resulted from the capture of metabolic genes by horizontal gene transfer from algal viruses, prokaryotes, or fungi. Analysis of the NC64A genome substantially advances our understanding of the green lineage evolution, including the genomic interplay with viruses and symbiosis between eukaryotes. PMID:20852019

  18. The Chlorella variabilis NC64A Genome Reveals Adaptation to Photosymbiosis, Coevolution with Viruses, and Cryptic Sex

    SciTech Connect

    Blanc, Guillaume; Duncan, Garry A.; Agarakova, Irina; Borodovsky, Mark; Gurnon, James; Kuo, Alan; Lindquist, Erika; Lucas, Susan; Pangailinan, Jasmyn; Polle, Juergen; Salamov, Asaf; Terry, Astrid; Yamada, Takashi; Dunigan, David D.; Grigoriev, Igor V.; Claverie, Jean-Michel; Etten, James L. Van

    2010-05-06

    Chlorella variabilis NC64A, a unicellular photosynthetic green alga (Trebouxiophyceae), is an intracellular photobiont of Paramecium bursaria and a model system for studying virus/algal interactions. We sequenced its 46-Mb nuclear genome, revealing an expansion of protein families that could have participated in adaptation to symbiosis. NC64A exhibits variations in GC content across its genome that correlate with global expression level, average intron size, and codon usage bias. Although Chlorella species have been assumed to be asexual and nonmotile, the NC64A genome encodes all the known meiosis-specific proteins and a subset of proteins found in flagella. We hypothesize that Chlorella might have retained a flagella-derived structure that could be involved in sexual reproduction. Furthermore, a survey of phytohormone pathways in chlorophyte algae identified algal orthologs of Arabidopsis thaliana genes involved in hormone biosynthesis and signaling, suggesting that these functions were established prior to the evolution of land plants. We show that the ability of Chlorella to produce chitinous cell walls likely resulted from the capture of metabolic genes by horizontal gene transfer from algal viruses, prokaryotes, or fungi. Analysis of the NC64A genome substantially advances our understanding of the green lineage evolution, including the genomic interplay with viruses and symbiosis between eukaryotes.

  19. Starch and lipid accumulation in eight strains of six Chlorella species under comparatively high light intensity and aeration culture conditions.

    PubMed

    Takeshita, Tsuyoshi; Ota, Shuhei; Yamazaki, Tomokazu; Hirata, Aiko; Zachleder, Vilém; Kawano, Shigeyuki

    2014-04-01

    The microalgae family Chlorella species are known to accumulate starch and lipids. Although nitrogen or phosphorous deficiencies promote starch and lipids formation in many microalgae, these deficiencies also limit their growth and productivity. Therefore, the Chlorellaceae strains were attempted to increase starch and lipids productivity under high-light-intensity conditions (600-μmol photons m(-2)s(-1)). The 12:12-h light-dark (LD) cycle conditions elicited more stable growth than the continuous light (LL) conditions, whereas the starch and lipids yields increased in LL conditions. The amount of starch and lipids per cell increased in Chlorella viscosa and Chlorella vulgaris in sulfur-deficient medium, and long-chain fatty acids with 20 or more carbon atoms accumulated in cells grown in sulfur-deficient medium. Accumulation of starch and lipids was investigated in eight strains. The accumulation was strain-dependent, and varied according to the medium and light conditions. Five of the eight Chlorella strains exhibited similar accumulation patterns.

  20. Quantification of nutrient-replete growth rates in five-ion hyperspace for Chlorella vulgaris (Trebouxiophyceae) and Peridinium cinctum (Dinophyceae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of five ions, NO3-, PO43-, K+, Na+ and Cl- on growth rates and cell densities were quantified for Chlorella vulgaris (Chlorophycea) and Peridinium cinctum (Dinophycea) in batch cultures. A five dimensional experimental design, the five component mixture design projected across a total i...

  1. Use of De Novo Transcriptome Libraries to Characterize a Novel Oleaginous Marine Chlorella Species during the Accumulation of Triacylglycerols.

    PubMed

    Mansfeldt, Cresten B; Richter, Lubna V; Ahner, Beth A; Cochlan, William P; Richardson, Ruth E

    2016-01-01

    Marine chlorophytes of the genus Chlorella are unicellular algae capable of accumulating a high proportion of cellular lipids that can be used for biodiesel production. In this study, we examined the broad physiological capabilities of a subtropical strain (C596) of Chlorella sp. "SAG-211-18" including its heterotrophic growth and tolerance to low salt. We found that the alga replicates more slowly at diluted salt concentrations and can grow on a wide range of carbon substrates in the dark. We then sequenced the RNA of Chlorella strain C596 to elucidate key metabolic genes and investigate the transcriptomic response of the organism when transitioning from a nutrient-replete to a nutrient-deficient condition when neutral lipids accumulate. Specific transcripts encoding for enzymes involved in both starch and lipid biosynthesis, among others, were up-regulated as the cultures transitioned into a lipid-accumulating state whereas photosynthesis-related genes were down-regulated. Transcripts encoding for two of the up-regulated enzymes-a galactoglycerolipid lipase and a diacylglyceride acyltransferase-were also monitored by reverse transcription quantitative polymerase chain reaction assays. The results of these assays confirmed the transcriptome-sequencing data. The present transcriptomic study will assist in the greater understanding, more effective application, and efficient design of Chlorella-based biofuel production systems.

  2. Use of De Novo transcriptome libraries to characterize a novel oleaginous marine Chlorella species during the accumulation of triacylglycerols

    DOE PAGESBeta

    Mansfeldt, Cresten B.; Richter, Lubna V.; Ahner, Beth A.; Cochlan, William P.; Richardson, Ruth E.; Chen, Shilin

    2016-02-03

    Here, marine chlorophytes of the genus Chlorella are unicellular algae capable of accumulating a high proportion of cellular lipids that can be used for biodiesel production. In this study, we examined the broad physiological capabilities of a subtropical strain (C596) of Chlorella sp. “SAG-211-18” including its heterotrophic growth and tolerance to low salt.We found that the alga replicates more slowly at diluted salt concentrations and can grow on a wide range of carbon substrates in the dark.We then sequenced the RNA of Chlorella strain C596 to elucidate key metabolic genes and investigate the transcriptomic response of the organism when transitioningmore » from a nutrient-replete to a nutrient-deficient condition when neutral lipids accumulate. Specific transcripts encoding for enzymes involved in both starch and lipid biosynthesis, among others, were up-regulated as the cultures transitioned into a lipid-accumulating state whereas photosynthesis-related genes were down-regulated. Transcripts encoding for two of the up-regulated enzymes—a galactoglycerolipid lipase and a diacylglyceride acyltransferase—were also monitored by reverse transcription quantitative polymerase chain reaction assays. The results of these assays confirmed the transcriptome-sequencing data. The present transcriptomic study will assist in the greater understanding, more effective application, and efficient design of Chlorella-based biofuel production systems.« less

  3. Lipid Production of Heterotrophic Chlorella sp. from Hydrolysate Mixtures of Lipid-Extracted Microalgal Biomass Residues and Molasses.

    PubMed

    Zheng, Hongli; Ma, Xiaochen; Gao, Zhen; Wan, Yiqin; Min, Min; Zhou, Wenguang; Li, Yun; Liu, Yuhuan; Huang, He; Chen, Paul; Ruan, Roger

    2015-10-01

    This study investigated the feasibility of lipid production of Chlorella sp. from waste materials. Lipid-extracted microalgal biomass residues (LMBRs) and molasses were hydrolyzed, and their hydrolysates were analyzed. Five different hydrolysate mixture ratios (w/w) of LMBRs/molasses (1/0, 1/1, 1/4, 1/9, and 0/1) were used to cultivate Chlorella sp. The results showed that carbohydrate and protein were the two main compounds in the LMBRs, and carbohydrate was the main compound in the molasses. The highest biomass concentration of 5.58 g/L, Y biomass/sugars of 0.59 g/g, lipid productivity of 335 mg/L/day, and Y lipids/sugars of 0.25 g/g were obtained at the hydrolysate mixture ratio of LMBRs/molasses of 1/4. High C/N ratio promoted the conversion of sugars into lipids. The lipids extracted from Chlorella sp. shared similar lipid profile of soybean oil and is therefore a potential viable biodiesel feedstock. These results showed that Chlorella sp. can utilize mixed sugars and amino acids from LMBRs and molasses to accumulate lipids efficiently, thus reducing the cost of microalgal biodiesel production and improving its economic viability.

  4. Use of De Novo Transcriptome Libraries to Characterize a Novel Oleaginous Marine Chlorella Species during the Accumulation of Triacylglycerols

    PubMed Central

    Ahner, Beth A.; Cochlan, William P.; Richardson, Ruth E.

    2016-01-01

    Marine chlorophytes of the genus Chlorella are unicellular algae capable of accumulating a high proportion of cellular lipids that can be used for biodiesel production. In this study, we examined the broad physiological capabilities of a subtropical strain (C596) of Chlorella sp. “SAG-211-18” including its heterotrophic growth and tolerance to low salt. We found that the alga replicates more slowly at diluted salt concentrations and can grow on a wide range of carbon substrates in the dark. We then sequenced the RNA of Chlorella strain C596 to elucidate key metabolic genes and investigate the transcriptomic response of the organism when transitioning from a nutrient-replete to a nutrient-deficient condition when neutral lipids accumulate. Specific transcripts encoding for enzymes involved in both starch and lipid biosynthesis, among others, were up-regulated as the cultures transitioned into a lipid-accumulating state whereas photosynthesis-related genes were down-regulated. Transcripts encoding for two of the up-regulated enzymes—a galactoglycerolipid lipase and a diacylglyceride acyltransferase—were also monitored by reverse transcription quantitative polymerase chain reaction assays. The results of these assays confirmed the transcriptome-sequencing data. The present transcriptomic study will assist in the greater understanding, more effective application, and efficient design of Chlorella-based biofuel production systems. PMID:26840425

  5. Enhanced accumulation of starch and total carbohydrates in alginate-immobilized Chlorella spp. induced by Azospirillum brasilense: II. Heterotrophic conditions.

    PubMed

    Choix, Francisco J; de-Bashan, Luz E; Bashan, Yoav

    2012-10-10

    The effect of the bacterium Azospirillum brasilense jointly immobilized with Chlorella vulgaris or C. sorokiniana in alginate beads on total carbohydrates and starch was studied under dark and heterotrophic conditions for 144 h in synthetic growth medium supplemented with either d-glucose or Na-acetate as carbon sources. In all treatments, enhanced total carbohydrates and starch content per culture and per cell was obtained after 24h; only jointly immobilized C. vulgaris growing on d-glucose significantly increased total carbohydrates and starch content after 96 h. Enhanced accumulation of carbohydrate and starch under jointly immobilized conditions was variable with time of sampling and substrate used. Similar results occurred when the microalgae was immobilized alone. In both microalgae growing on either carbon sources, the bacterium promoted accumulation of carbohydrates and starch; when the microalgae were immobilized alone, they used the carbon sources for cell multiplication. In jointly immobilized conditions with Chlorella spp., affinity to carbon source and volumetric productivity and yield were higher than when Chlorella spp. were immobilized alone; however, the growth rate was higher in microalgae immobilized alone. This study demonstrates that under heterotrophic conditions, A. brasilense promotes the accumulation of carbohydrates in two strains Chlorella spp. under certain time-substrate combinations, producing mainly starch. As such, this bacterium is a biological factor that can change the composition of compounds in microalgae in dark, heterotrophic conditions.

  6. The Chlorella variabilis NC64A genome reveals adaptation to photosymbiosis, coevolution with viruses, and cryptic sex.

    PubMed

    Blanc, Guillaume; Duncan, Garry; Agarkova, Irina; Borodovsky, Mark; Gurnon, James; Kuo, Alan; Lindquist, Erika; Lucas, Susan; Pangilinan, Jasmyn; Polle, Juergen; Salamov, Asaf; Terry, Astrid; Yamada, Takashi; Dunigan, David D; Grigoriev, Igor V; Claverie, Jean-Michel; Van Etten, James L

    2010-09-01

    Chlorella variabilis NC64A, a unicellular photosynthetic green alga (Trebouxiophyceae), is an intracellular photobiont of Paramecium bursaria and a model system for studying virus/algal interactions. We sequenced its 46-Mb nuclear genome, revealing an expansion of protein families that could have participated in adaptation to symbiosis. NC64A exhibits variations in GC content across its genome that correlate with global expression level, average intron size, and codon usage bias. Although Chlorella species have been assumed to be asexual and nonmotile, the NC64A genome encodes all the known meiosis-specific proteins and a subset of proteins found in flagella. We hypothesize that Chlorella might have retained a flagella-derived structure that could be involved in sexual reproduction. Furthermore, a survey of phytohormone pathways in chlorophyte algae identified algal orthologs of Arabidopsis thaliana genes involved in hormone biosynthesis and signaling, suggesting that these functions were established prior to the evolution of land plants. We show that the ability of Chlorella to produce chitinous cell walls likely resulted from the capture of metabolic genes by horizontal gene transfer from algal viruses, prokaryotes, or fungi. Analysis of the NC64A genome substantially advances our understanding of the green lineage evolution, including the genomic interplay with viruses and symbiosis between eukaryotes. PMID:20852019

  7. Optimization of pressurized liquid extraction of carotenoids and chlorophylls from Chlorella vulgaris.

    PubMed

    Cha, Kwang Hyun; Lee, Hee Ju; Koo, Song Yi; Song, Dae-Geun; Lee, Dong-Un; Pan, Cheol-Ho

    2010-01-27

    Pressurized liquid extraction (PLE) was applied to the extraction of carotenoids and chlorophylls from the green microalga Chlorella vulgaris. Four extraction techniques such as maceration (MAC), Soxhlet extraction (SOX), ultrasound assisted extraction (UAE), and PLE were compared, and both the extraction temperature (50, 105, and 160 degrees C) and the extraction time (8, 19, and 30 min), which are the two main factors for PLE, were optimized with a central composite design to obtain the highest extraction efficiency. The extraction solvent (90% ethanol/water) could adequately extract the functional components from C. vulgaris. PLE showed higher extraction efficiencies than MAC, SOX, and UAE. Temperature was the key parameter having the strongest influence on the extraction of carotenoids and chlorophylls from chlorella. In addition, high heat treatment (>110 degrees C) by PLE minimized the formation of pheophorbide a, a harmful chlorophyll derivative. These results indicate that PLE may be a useful extraction method for the simultaneous extraction of carotenoids and chlorophylls from C. vulgaris. PMID:20028017

  8. High efficient treatment of citric acid effluent by Chlorella vulgaris and potential biomass utilization.

    PubMed

    Li, Changling; Yang, Hailin; Xia, Xiaole; Li, Yuji; Chen, Luping; Zhang, Meng; Zhang, Ling; Wang, Wu

    2013-01-01

    The efficiency of treating citric acid effluent by green algae Chlorella was investigated. With the highest growth rate, Chlorella vulgaris C9-JN2010 that could efficiently remove nutrients in the citric acid effluent was selected for scale-up batch experiments under the optimal conditions, where its maximum biomass was 1.04 g l(-1) and removal efficiencies of nutrients (nitrogen, phosphorus, total organic carbon, chemical oxygen demand and biochemical oxygen demand) were above 90.0%. Algal lipid and protein contents were around 340.0 and 500.0 mg · g(-1) of the harvested biomass, respectively. Proportions of polyunsaturated fatty acids in the lipids and eight kinds of essential amino acids in algal protein were 74.0% and 40.0%, respectively. Three major fatty acids were hexadecanoic acid, eicosapentaenoic acid and docosadienoic acid. This specific effluent treatment process could be proposed as a dual-beneficial approach, which converts nutrients in the high strength citric acid effluent into profitable byproducts and reduces the contaminations.

  9. Assessment of bioavailability of heavy metal pollutants using soil isolates of Chlorella sp.

    PubMed

    Krishnamurti, Gummuluru S R; Subashchandrabose, Suresh R; Megharaj, Mallavarapu; Naidu, Ravi

    2015-06-01

    Biotests conducted with plants are presently used to estimate metal bioavailability in contaminated soils. But when plants are grown in soils, especially the plants with fine roots, root collection is easily biased and tedious. Indeed, at harvest, small amounts of soil can adhere to roots, resulting in overestimation of root metal content, and the finest roots are often discarded from the analysis because of their difficult and almost impossible recovery. This report presents a novel method for assessing the bioavailability of heavy metals in soils using microalgae. Two species of green unicellular microalgae were isolated from two highly contaminated soils and identified by phylogenetic and molecular evolutionary analyses as Chlorella sp. RBM and Chlorella sp. RHM. These two cultures were used to determine the metal uptake from metal-contaminated soils of South Australia as a novel, cost-effective, simple and rapid method for assessing the bioavailability of heavy metals in soils. The suggested method is an attempt to achieve a realistic estimate of bioavailability which overcomes the inherent drawback of root metal contamination in the bioavailability indices so far reported.

  10. Investigation of mixotrophic, heterotrophic, and autotrophic growth of Chlorella vulgaris under agricultural waste medium.

    PubMed

    Mohammad Mirzaie, M A; Kalbasi, M; Mousavi, S M; Ghobadian, B

    2016-01-01

    Growth of Chlorella vulgaris and its lipid production were investigated under autotrophic, heterotrophic, and mixotrophic conditions. Cheap agricultural waste molasses and corn steep liquor from industries were used as carbon and nitrogen sources, respectively. Chlorella vulgaris grew remarkably under this agricultural waste medium, which resulted in a reduction in the final cost of the biodiesel production. Maximum dry weight of 2.62 g L(-1) was obtained in mixotrophic growth with the highest lipid concentration of 0.86 g L(-1). These biomass and lipid concentrations were, respectively, 140% and 170% higher than autotrophic growth and 300% and 1200% higher than heterotrophic growth. In mixotrophic growth, independent or simultaneous occurrence of autotrophic and heterotrophic metabolisms was investigated. The growth of the microalgae was observed to take place first heterotrophically to a minimum substrate concentration with a little fraction in growth under autotrophic metabolism, and then the cells grew more autotrophically. It was found that mixotrophic growth was not a simple combination of heterotrophic and autotrophic growth.

  11. CLONING AND EXPRESSING TRYPSIN MODULATING OOSTATIC FACTOR IN Chlorella desiccata TO CONTROL MOSQUITO LARVAE.

    PubMed

    Borovsky, Dov; Sterner, Andeas; Powell, Charles A

    2016-01-01

    The insect peptide hormone trypsin modulating oostatic factor (TMOF), a decapeptide that is synthesized by the mosquito ovary and controls the translation of the gut's trypsin mRNA was cloned and expressed in the marine alga Chlorella desiccata. To express Aedes aegypti TMOF gene (tmfA) in C. desiccata cells, two plasmids (pYES2/TMOF and pYDB4-tmfA) were engineered with pKYLX71 DNA (5 Kb) carrying the cauliflower mosaic virus (CaMV) promoter 35S(2) and the kanamycin resistant gene (neo), as well as, a 8 Kb nitrate reductase gene (nit) from Chlorella vulgaris. Transforming C. desiccata with pYES2/TMOF and pYDB4-tmfA show that the engineered algal cells express TMOF (20 ± 4 μg ± SEM and 17 ± 3 μg ± SEM, respectively in 3 × 10(8) cells) and feeding the cells to mosquito larvae kill 75 and 60% of Ae. aegypti larvae in 4 days, respectively. Southern and Northern blots analyses show that tmfA integrated into the genome of C. desiccata by homologous recombination using the yeast 2 μ circle of replication and the nit in pYES2/TMOF and pYDB4-tmfA, respectively, and the transformed algal cells express tmfA transcript. Using these algal cells it will be possible in the future to control mosquito larvae in the marsh.

  12. Cultivation of Chlorella vulgaris in Column Photobioreactor for Biomass Production and Lipid Accumulation.

    PubMed

    Wong, Y K; Ho, K C; Tsang, Y F; Wang, L; Yung, K K L

    2016-01-01

    Microalgae have been used as energy resources in recent decades to mitigate the global energy crisis. As the demand for pure microalgae strains for commercial use increases, designing an effective photobioreactor (PBR) for mass cultivation is important. Chlorella vulgaris, a local freshwater microalga, was used to study the algal biomass cultivation and lipid production using various PBR configurations (bubbling, air-lift, porous air-lift). The results show that a bubbling column design is a better choice for the cultivation of Chlorella vulgaris than an air-lift one. The highest biomass concentration in the bubbling PBR was 0.78 g/L while the air-lift PBR had a value of 0.09 g/L. Key operating parameters, including draft-tube length and bubbling flowrate, were then optimized based on biomass production and lipid yield. The highest lipid content was in the porous air-lift PBR and the air-lift PBR with shorter draft tube (35 cm) was also better than a longer one (50 cm) for algal cultivation, but the microalgae attachment on the inner tube of PBR always occurred. The highest biomass concentration could be produced under the highest gas flowrate of 2.7 L/min, whereas the lowest dry cell mass was under the lowest gas flowrate of 0.2 L/min.

  13. Investigation of mixotrophic, heterotrophic, and autotrophic growth of Chlorella vulgaris under agricultural waste medium.

    PubMed

    Mohammad Mirzaie, M A; Kalbasi, M; Mousavi, S M; Ghobadian, B

    2016-01-01

    Growth of Chlorella vulgaris and its lipid production were investigated under autotrophic, heterotrophic, and mixotrophic conditions. Cheap agricultural waste molasses and corn steep liquor from industries were used as carbon and nitrogen sources, respectively. Chlorella vulgaris grew remarkably under this agricultural waste medium, which resulted in a reduction in the final cost of the biodiesel production. Maximum dry weight of 2.62 g L(-1) was obtained in mixotrophic growth with the highest lipid concentration of 0.86 g L(-1). These biomass and lipid concentrations were, respectively, 140% and 170% higher than autotrophic growth and 300% and 1200% higher than heterotrophic growth. In mixotrophic growth, independent or simultaneous occurrence of autotrophic and heterotrophic metabolisms was investigated. The growth of the microalgae was observed to take place first heterotrophically to a minimum substrate concentration with a little fraction in growth under autotrophic metabolism, and then the cells grew more autotrophically. It was found that mixotrophic growth was not a simple combination of heterotrophic and autotrophic growth. PMID:25807048

  14. Viruses of symbiotic Chlorella-like algae isolated from Paramecium bursaria and Hydra viridis

    PubMed Central

    Van Etten, James L.; Meints, Russel H.; Kuczmarski, Daniel; Burbank, Dwight E.; Lee, Kit

    1982-01-01

    We previously reported that isolation of symbiotic Chlorella-like algae from the Florida strain of Hydra viridis induced replication of a virus (designated HVCV-1) in the algae. We now report that isolation of symbiotic Chlorella-like algae from four other sources of green hydra and one source of the protozoan Paramecium bursaria also induced virus synthesis. Algae from one of these hydra contained a virus identical to HVCV-1 (based on its rate of sedimentation, buoyant density, reaction to HVCV-1 antiserum, and DNA restriction fragments) whereas algae from the other three hydra contained another similar, but distinct, virus (designated HVCV-2). The virus from the paramecium algae (designated PBCV-1) was distinct from both HVCV-1 and HVCV-2. The symbiotic algae in the hydra could also be distinguished ultrastructurally. Chloroplasts of both algae that produced HVCV-1 lacked a pyrenoid whereas chloroplasts of the other three symbiotic algae contained pyrenoids. Since all symbiotic eukaryotic algae we have examined have had virus, a potential viral role in symbiosis is suggested. Images PMID:16593198

  15. Biohydrogen production by immobilized Chlorella sp. using cycles of oxygenic photosynthesis and anaerobiosis.

    PubMed

    Song, Wei; Rashid, Naim; Choi, Wookjin; Lee, Kisay

    2011-09-01

    Hydrogen production was studied using immobilized green alga Chlorella sp. through a two-stage cyclic process where immobilized cells were first incubated in oxygenic photosynthesis followed by anaerobic incubation for H2 production in the absence of sulfur. Chlorella sp. used in this study was capable of generating H2 under immobilized state in agar. The externally added glucose enhanced H2 production rates and total produced volume while shortened the lag time required for cell adaptation prior to H2 evolution. The rate of hydrogen evolution was increased as temperature increased, and the maximum evolution rate under 30 mM glucose was 183 mL/h/L and 238 mL/h/L at 37 °C and 40 °C, respectively. In order to continue repeated cycles of H2 production, at least two days of photosynthesis stage should be allowed for cells to recover H2 production potential and cell viability before returning to H2 production stage again.

  16. Formation of elemental sulfur by Chlorella fusca during growth on L-cysteine ethylester

    SciTech Connect

    Krauss, F.; Schafer, W.; Schmidt, A.

    1984-01-01

    During growth on L-cysteine ethylester, Chlorella fusca (211-8b) accumulated a substance which contained bound sulfide, which could be liberated by reduction with dithioerythritol (DTE) as inorganic sulfide. This substance was extracted with hot methanol and purified by thin layer chromatography. This substance liberated free sulfide when incubated with mono- and dithiols, and thiocyanate was formed after heating with KCN. The isolated substance cochromatographed with authentic sulfur flower using different solvent systems for thin layer chromatography, high pressure liquid chromatography, and the identical spectrum with a relative ..beta..max at 263 nm was found. The chemical structure was confirmed by mass spectrometry showing a molecular weight of 256 m/e for the S/sub 8/ configuration. No labeled elemental sulfur was detected when the cells were grown on (/sup 35/S)sulfate and L-cysteine ethylester. C. fusca seems to have enzymes for the metabolism of elemental sulfur, since it disappeared after prolonged growth into the stationary phase. Cysteine was formed from O-acetyl-L-serine and elemental sulfur in the presence of thiol groups and purified cysteine synthase from spinach or Chlorella.

  17. Paramecium bursaria chlorella virus 1 proteome reveals novel architectural and regulatory features of a giant virus.

    PubMed

    Dunigan, David D; Cerny, Ronald L; Bauman, Andrew T; Roach, Jared C; Lane, Leslie C; Agarkova, Irina V; Wulser, Kurt; Yanai-Balser, Giane M; Gurnon, James R; Vitek, Jason C; Kronschnabel, Bernard J; Jeanniard, Adrien; Blanc, Guillaume; Upton, Chris; Duncan, Garry A; McClung, O William; Ma, Fangrui; Van Etten, James L

    2012-08-01

    The 331-kbp chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) genome was resequenced and annotated to correct errors in the original 15-year-old sequence; 40 codons was considered the minimum protein size of an open reading frame. PBCV-1 has 416 predicted protein-encoding sequences and 11 tRNAs. A proteome analysis was also conducted on highly purified PBCV-1 virions using two mass spectrometry-based protocols. The mass spectrometry-derived data were compared to PBCV-1 and its host Chlorella variabilis NC64A predicted proteomes. Combined, these analyses revealed 148 unique virus-encoded proteins associated with the virion (about 35% of the coding capacity of the virus) and 1 host protein. Some of these proteins appear to be structural/architectural, whereas others have enzymatic, chromatin modification, and signal transduction functions. Most (106) of the proteins have no known function or homologs in the existing gene databases except as orthologs with proteins of other chloroviruses, phycodnaviruses, and nuclear-cytoplasmic large DNA viruses. The genes encoding these proteins are dispersed throughout the virus genome, and most are transcribed late or early-late in the infection cycle, which is consistent with virion morphogenesis.

  18. Improved Productivity of Neutral Lipids in Chlorella sp. A2 by Minimal Nitrogen Supply

    PubMed Central

    Zhu, Junying; Chen, Weixian; Chen, Hui; Zhang, Xin; He, Chenliu; Rong, Junfeng; Wang, Qiang

    2016-01-01

    Nitrogen starvation is an efficient environmental pressure for increasing lipid accumulation in microalgae, but it could also significantly lower the biomass productivity, resulting in lower lipid productivity. In this study, green alga Chlorella sp. A2 was cultivated by using a minimal nitrogen supply strategy under both laboratory and outdoor cultivation conditions to evaluate biomass accumulation and lipid production. Results showed that minimal nitrogen supply could promote neutral lipid accumulation of Chlorella sp. A2 without a significant negative effect on cell growth. In laboratory cultivation mode, alga cells cultured with 18 mg L−1 d−1 urea addition could generate 74 and 416% (w/w) more neutral lipid productivity than cells cultured with regular BG11 and nitrogen starvation media, respectively. In outdoor cultivation mode, lipid productivity of cells cultured with 18 mg L−1 d−1 urea addition is approximately 10 and 88% higher than the one with regular BG11 and nitrogen starvation media, respectively. Notably, the results of photosynthetic analysis clarified that minimal nitrogen supply reduced the loss of photosynthetic capacity to keep CO2 fixation during photosynthesis for biomass production. The minimal nitrogen supply strategy for microalgae cultivation could promote neutral lipid accumulation without a significant negative effect on cell growth, resulting in a significant improvement in the lipid productivity. PMID:27148237

  19. Formation of Elemental Sulfur by Chlorella fusca during Growth on l-Cysteine Ethylester 1

    PubMed Central

    Krauss, Friedrich; Schäfer, Wolfram; Schmidt, Ahlert

    1984-01-01

    During growth on l-cysteine ethylester, Chlorella fusca (211-8b) accumulated a substance which contained bound sulfide, which could be liberated by reduction with dithioerythritol (DTE) as inorganic sulfide. This substance was extracted with hot methanol and purified by thin layer chromatography. This substance liberated free sulfide when incubated with mono- and dithiols, and thiocyanate was formed after heating with KCN. The isolated substance cochromatographed with authentic sulfur flower using different solvent systems for thin layer chromatography, high pressure liquid chromatography, and the identical spectrum with a relative λmax at 263 nm was found. The chemical structure was confirmed by mass spectrometry showing a molecular weight of 256 m/e for the S8 configuration. No labeled elemental sulfur was detected when the cells were grown on [35S]sulfate and l-cysteine ethylester indicating the origin of elemental sulfur from l-cysteine ethylester. C. fusca seems to have enzymes for the metabolism of elemental sulfur, since it disappeared after prolonged growth into the stationary phase. Cysteine was formed from O-acetyl-l-serine and elemental sulfur in the presence of thiol groups and purified cysteine synthase from spinach or Chlorella. PMID:16663375

  20. Streptomycin affects the growth and photochemical activity of the alga Chlorella vulgaris.

    PubMed

    Perales-Vela, Hugo Virgilio; García, Roberto Velasco; Gómez-Juárez, Evelyn Alicia; Salcedo-Álvarez, Martha Ofelia; Cañizares-Villanueva, Rosa Olivia

    2016-10-01

    Antibiotics are increasingly being used in human and veterinary medicine, as well as pest control in agriculture. Recently, their emergence in the aquatic environment has become a global concern. The aim of this study was to evaluate the effect of streptomycin on growth and photosynthetic activity of Chlorella vulgaris after 72h exposure. We found that growth, photosynthetic activity and the content of the D1 protein of photosystem II decreased. Analysis of chlorophyll a fluorescence emission shows a reduction in the energy transfer between the antenna complex and reaction center. Also the activity of the oxygen evolution complex and electron flow between QA and QB were significantly reduced; in contrast, we found an increase in the reduction rate of the acceptor side of photosystem I. The foregoing can be attributed to the inhibition of the synthesis of the D1 protein and perhaps other coded chloroplast proteins that are part of the electron transport chain which are essential for the transformation of solar energy in the photosystems. We conclude that micromolar concentrations of streptomycin can affect growth and photosynthetic activity of Chlorella vulgaris. The accumulation of antibiotics in the environment can become an ecological problem for primary producers in the aquatic environment. PMID:27344399

  1. Improved Productivity of Neutral Lipids in Chlorella sp. A2 by Minimal Nitrogen Supply.

    PubMed

    Zhu, Junying; Chen, Weixian; Chen, Hui; Zhang, Xin; He, Chenliu; Rong, Junfeng; Wang, Qiang

    2016-01-01

    Nitrogen starvation is an efficient environmental pressure for increasing lipid accumulation in microalgae, but it could also significantly lower the biomass productivity, resulting in lower lipid productivity. In this study, green alga Chlorella sp. A2 was cultivated by using a minimal nitrogen supply strategy under both laboratory and outdoor cultivation conditions to evaluate biomass accumulation and lipid production. Results showed that minimal nitrogen supply could promote neutral lipid accumulation of Chlorella sp. A2 without a significant negative effect on cell growth. In laboratory cultivation mode, alga cells cultured with 18 mg L(-1) d(-1) urea addition could generate 74 and 416% (w/w) more neutral lipid productivity than cells cultured with regular BG11 and nitrogen starvation media, respectively. In outdoor cultivation mode, lipid productivity of cells cultured with 18 mg L(-1) d(-1) urea addition is approximately 10 and 88% higher than the one with regular BG11 and nitrogen starvation media, respectively. Notably, the results of photosynthetic analysis clarified that minimal nitrogen supply reduced the loss of photosynthetic capacity to keep CO2 fixation during photosynthesis for biomass production. The minimal nitrogen supply strategy for microalgae cultivation could promote neutral lipid accumulation without a significant negative effect on cell growth, resulting in a significant improvement in the lipid productivity. PMID:27148237

  2. Streptomycin affects the growth and photochemical activity of the alga Chlorella vulgaris.

    PubMed

    Perales-Vela, Hugo Virgilio; García, Roberto Velasco; Gómez-Juárez, Evelyn Alicia; Salcedo-Álvarez, Martha Ofelia; Cañizares-Villanueva, Rosa Olivia

    2016-10-01

    Antibiotics are increasingly being used in human and veterinary medicine, as well as pest control in agriculture. Recently, their emergence in the aquatic environment has become a global concern. The aim of this study was to evaluate the effect of streptomycin on growth and photosynthetic activity of Chlorella vulgaris after 72h exposure. We found that growth, photosynthetic activity and the content of the D1 protein of photosystem II decreased. Analysis of chlorophyll a fluorescence emission shows a reduction in the energy transfer between the antenna complex and reaction center. Also the activity of the oxygen evolution complex and electron flow between QA and QB were significantly reduced; in contrast, we found an increase in the reduction rate of the acceptor side of photosystem I. The foregoing can be attributed to the inhibition of the synthesis of the D1 protein and perhaps other coded chloroplast proteins that are part of the electron transport chain which are essential for the transformation of solar energy in the photosystems. We conclude that micromolar concentrations of streptomycin can affect growth and photosynthetic activity of Chlorella vulgaris. The accumulation of antibiotics in the environment can become an ecological problem for primary producers in the aquatic environment.

  3. CLONING AND EXPRESSING TRYPSIN MODULATING OOSTATIC FACTOR IN Chlorella desiccata TO CONTROL MOSQUITO LARVAE.

    PubMed

    Borovsky, Dov; Sterner, Andeas; Powell, Charles A

    2016-01-01

    The insect peptide hormone trypsin modulating oostatic factor (TMOF), a decapeptide that is synthesized by the mosquito ovary and controls the translation of the gut's trypsin mRNA was cloned and expressed in the marine alga Chlorella desiccata. To express Aedes aegypti TMOF gene (tmfA) in C. desiccata cells, two plasmids (pYES2/TMOF and pYDB4-tmfA) were engineered with pKYLX71 DNA (5 Kb) carrying the cauliflower mosaic virus (CaMV) promoter 35S(2) and the kanamycin resistant gene (neo), as well as, a 8 Kb nitrate reductase gene (nit) from Chlorella vulgaris. Transforming C. desiccata with pYES2/TMOF and pYDB4-tmfA show that the engineered algal cells express TMOF (20 ± 4 μg ± SEM and 17 ± 3 μg ± SEM, respectively in 3 × 10(8) cells) and feeding the cells to mosquito larvae kill 75 and 60% of Ae. aegypti larvae in 4 days, respectively. Southern and Northern blots analyses show that tmfA integrated into the genome of C. desiccata by homologous recombination using the yeast 2 μ circle of replication and the nit in pYES2/TMOF and pYDB4-tmfA, respectively, and the transformed algal cells express tmfA transcript. Using these algal cells it will be possible in the future to control mosquito larvae in the marsh. PMID:26440910

  4. Enhancement of Chlorella vulgaris growth and bioremediation ability of aquarium wastewater using diazotrophs.

    PubMed

    Ali, Sayeda Mohammed; Nasr, Hoda Shafeek; Abbas, Wafaa Tawfik

    2012-08-15

    Treatment of aquarium wastewater represents an important process to clean and recycle wastewater to be safely returned to the environment, used for cultivation or to minimize the multiple renewal of water. Chlorella vulgaris was an important freshwater microalgae which used in wastewater treatment, and increasing its potential of treatment can be achieved with existence of N2-fixing bacteria. Co-culturing of Chlorella vulgaris with the diazotrophs, Azospirillum brasilense or Azotobacter chroococcum in three different media; aquarium wastewater (AWW), sterile enriched natural aquarium wastewater (GPM) and synthetic wastewater media (SWW) were studied. Biomass yield of the microalgae was estimated by determination of chlorophylls (a and b), total carotenoid and the dry weight of C. vulgaris. Also determination of ammonia, nitrite, phosphate and nitrate in the culture were done. The presence of diazotrophs significantly increased the biomass of C. vulgaris by increasing its microalgae pigments (chlorophylls a and b, and total carotenoids). The highest pigments percentage was reported due to addition of A. brasilense to C. vulgaris (18.3-133.5%) compared to A. chroococcum (23.9-56.9%). As well as increased dry weight from 12 to 50%. There was also improved removal of nitrate, nitrite, ammonia and phosphate; where, the highest removal percentage was reported due to addition of A. chroococcum to C. vulgaris (0.0-52%) compared to A. brasilense (0.6-16.4%). A. brasilense and A. chroococcum can support C. vulgaris biomass production and bioremediation activity in the aquarium to minimize the periodical water renewal.

  5. The Effects of Physicochemical Factors and Cell Density on Nitrite Transformation in a Lipid-Rich Chlorella.

    PubMed

    Liang, Fang; Du, Kui; Wen, Xiaobin; Luo, Liming; Geng, Yahong; Li, Yeguang

    2015-12-28

    To understand the effects of physicochemical factors on nitrite transformation by microalgae, a lipid-rich Chlorella with high nitrite tolerance was cultured with 8 mmol/l sodium nitrite as sole nitrogen source under different conditions. The results showed that nitrite transformation was mainly dependent on the metabolic activities of algal cells rather than oxidation of nitrite by dissolved oxygen. Light intensity, temperature, pH, NaHCO3 concentrations, and initial cell densities had significant effects on the rate of nitrite transformation. Single-factor experiments revealed that the optimum conditions for nitrite transformation were light intensity: 300 μmol/m(2); temperature: 30°C; pH: 7-8; NaHCO3 concentration: 2.0 g/l; and initial cell density: 0.15 g/l; and the highest nitrite transformation rate of 1.36 mmol/l/d was achieved. There was a positive correlation between nitrite transformation rate and the growth of Chlorella. The relationship between nitrite transformation rate (mg/l/d) and biomass productivity (g/l/d) could be described by the regression equation y = 61.3x (R(2) = 0.9665), meaning that 61.3 mg N element was assimilated by 1.0 g dry biomass on average, which indicated that the nitrite transformation is a process of consuming nitrite as nitrogen source by Chlorella. The results demonstrated that the Chlorella suspension was able to assimilate nitrite efficiently, which implied the feasibility of using flue gas for mass production of Chlorella without preliminary removal of NOX.

  6. Prediction of ecotoxicological behavior of chemicals: relationship between n-octanol/water partition coefficient and bioaccumulation of organic chemicals by alga Chlorella

    SciTech Connect

    Geyer, H.; Politzki, G.; Freitag, D.

    1984-01-01

    The bioaccumulation potential of organic chemicals by the green alga Chlorella fusca was determined. A quantitative relationship was found to exist between the lipophilicity (n-octanol/water partition coefficient) of the chemicals and the bioaccumulation factor.

  7. Interactive Effects of Temperature and UV Radiation on Photosynthesis of Chlorella Strains from Polar, Temperate and Tropical Environments: Differential Impacts on Damage and Repair

    PubMed Central

    Wong, Chiew-Yen; Teoh, Ming-Li; Phang, Siew-Moi; Lim, Phaik-Eem; Beardall, John

    2015-01-01

    Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400–700 nm), PAR plus ultraviolet-A (320–400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280–320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain

  8. Interactive Effects of Temperature and UV Radiation on Photosynthesis of Chlorella Strains from Polar, Temperate and Tropical Environments: Differential Impacts on Damage and Repair.

    PubMed

    Wong, Chiew-Yen; Teoh, Ming-Li; Phang, Siew-Moi; Lim, Phaik-Eem; Beardall, John

    2015-01-01

    Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400-700 nm), PAR plus ultraviolet-A (320-400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280-320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain

  9. Interactive Effects of Temperature and UV Radiation on Photosynthesis of Chlorella Strains from Polar, Temperate and Tropical Environments: Differential Impacts on Damage and Repair.

    PubMed

    Wong, Chiew-Yen; Teoh, Ming-Li; Phang, Siew-Moi; Lim, Phaik-Eem; Beardall, John

    2015-01-01

    Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400-700 nm), PAR plus ultraviolet-A (320-400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280-320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain

  10. Identity and physiology of a new psychrophilic eukaryotic green alga, Chlorella sp., strain BI, isolated from a transitory pond near Bratina Island, Antarctica

    USGS Publications Warehouse

    Morgan-Kiss, R. M.; Ivanov, A.G.; Modla, S.; Czymmek, K.; Huner, N.P.A.; Priscu, J.C.; Lisle, J.T.; Hanson, T.E.

    2008-01-01

    Permanently low temperature environments are one of the most abundant microbial habitats on earth. As in most ecosystems, photosynthetic organisms drive primary production in low temperature food webs. Many of these phototrophic microorganisms are psychrophilic; however, functioning of the photosynthetic processes of these enigmatic psychrophiles (the 'photopsychrophiles') in cold environments is not well understood. Here we describe a new chlorophyte isolated from a low temperature pond, on the Ross Ice Shelf near Bratina Island, Antarctica. Phylogenetic and morphological analyses place this strain in the Chlorella clade, and we have named this new chlorophyte Chlorella BI. Chlorella BI is a psychrophilic species, exhibiting optimum temperature for growth at around 10??C. However, psychrophily in the Antarctic Chlorella was not linked to high levels of membrane-associated poly-unsaturated fatty acids. Unlike the model Antarctic lake alga, Chlamydomonas raudensis UWO241, Chlorella BI has retained the ability for dynamic short term adjustment of light energy distribution between photosystem II (PS II) and photosystem I (PS I). In addition, Chlorella BI can grow under a variety of trophic modes, including heterotrophic growth in the dark. Thus, this newly isolated photopsychrophile has retained a higher versatility in response to environmental change than other well studied cold-adapted chlorophytes. ?? 2008 Springer.

  11. Global Analysis of Chlorella variabilis NC64A mRNA Profiles during the Early Phase of Paramecium bursaria Chlorella Virus-1 Infection

    PubMed Central

    Rowe, Janet M.; Jeanniard, Adrien; Gurnon, James R.; Xia, Yuannan; Dunigan, David D.; Van Etten, James L.; Blanc, Guillaume

    2014-01-01

    The PBCV-1/Chlorella variabilis NC64A system is a model for studies on interactions between viruses and algae. Here we present the first global analyses of algal host transcripts during the early stages of infection, prior to virus replication. During the course of the experiment stretching over 1 hour, about a third of the host genes displayed significant changes in normalized mRNA abundance that either increased or decreased compared to uninfected levels. The population of genes with significant transcriptional changes gradually increased until stabilizing at 40 minutes post infection. Functional categories including cytoplasmic ribosomal proteins, jasmonic acid biosynthesis and anaphase promoting complex/cyclosomes had a significant excess in upregulated genes, whereas spliceosomal snRNP complexes and the shikimate pathway had significantly more down-regulated genes, suggesting that these pathways were activated or shut-down in response to the virus infection. Lastly, we examined the expression of C. varibilis RNA polymerase subunits, as PBCV-1 transcription depends on host RNA polymerases. Two subunits were up-regulated, RPB10 and RPC34, suggesting that they may function to support virus transcription. These results highlight genes and pathways, as well as overall trends, for further refinement of our understanding of the changes that take place during the early stages of viral infection. PMID:24608695

  12. Global analysis of Chlorella variabilis NC64A mRNA profiles during the early phase of Paramecium bursaria chlorella virus-1 infection.

    PubMed

    Rowe, Janet M; Jeanniard, Adrien; Gurnon, James R; Xia, Yuannan; Dunigan, David D; Van Etten, James L; Blanc, Guillaume

    2014-01-01

    The PBCV-1/Chlorella variabilis NC64A system is a model for studies on interactions between viruses and algae. Here we present the first global analyses of algal host transcripts during the early stages of infection, prior to virus replication. During the course of the experiment stretching over 1 hour, about a third of the host genes displayed significant changes in normalized mRNA abundance that either increased or decreased compared to uninfected levels. The population of genes with significant transcriptional changes gradually increased until stabilizing at 40 minutes post infection. Functional categories including cytoplasmic ribosomal proteins, jasmonic acid biosynthesis and anaphase promoting complex/cyclosomes had a significant excess in upregulated genes, whereas spliceosomal snRNP complexes and the shikimate pathway had significantly more down-regulated genes, suggesting that these pathways were activated or shut-down in response to the virus infection. Lastly, we examined the expression of C. varibilis RNA polymerase subunits, as PBCV-1 transcription depends on host RNA polymerases. Two subunits were up-regulated, RPB10 and RPC34, suggesting that they may function to support virus transcription. These results highlight genes and pathways, as well as overall trends, for further refinement of our understanding of the changes that take place during the early stages of viral infection.

  13. Toxicity of arsenic species to three freshwater organisms and biotransformation of inorganic arsenic by freshwater phytoplankton (Chlorella sp. CE-35).

    PubMed

    Rahman, M Azizur; Hogan, Ben; Duncan, Elliott; Doyle, Christopher; Krassoi, Rick; Rahman, Mohammad Mahmudur; Naidu, Ravi; Lim, Richard P; Maher, William; Hassler, Christel

    2014-08-01

    In the environment, arsenic (As) exists in a number of chemical species, and arsenite (As(III)) and arsenate (As(V)) dominate in freshwater systems. Toxicity of As species to aquatic organisms is complicated by their interaction with chemicals in water such as phosphate that can influence the bioavailability and uptake of As(V). In the present study, the toxicities of As(III), As(V) and dimethylarsinic acid (DMA) to three freshwater organisms representing three phylogenetic groups: a phytoplankton (Chlorella sp. strain CE-35), a floating macrophyte (Lemna disperma) and a cladoceran grazer (Ceriodaphnia cf. dubia), were determined using acute and growth inhibition bioassays (EC₅₀) at a range of total phosphate (TP) concentrations in OECD medium. The EC₅₀ values of As(III), As(V) and DMA were 27 ± 10, 1.15 ± 0.04 and 19 ± 3 mg L(-1) for Chlorella sp. CE-35; 0.57 ± 0.16, 2.3 ± 0.2 and 56 ± 15 mg L(-1) for L. disperma, and 1.58 ± 0.05, 1.72 ± 0.01 and 5.9 ± 0.1 mg L(-1) for C. cf. dubia, respectively. The results showed that As(III) was more toxic than As(V) to L. disperma; however, As(V) was more toxic than As(III) to Chlorella sp. CE-35. The toxicities of As(III) and As(V) to C. cf. dubia were statistically similar (p>0.05). DMA was less toxic than iAs species to L. disperma and C. cf. dubia, but more toxic than As(III) to Chlorella sp. CE-35. The toxicity of As(V) to Chlorella sp. CE-35 and L. disperma decreased with increasing TP concentrations in the growth medium. Phosphate concentrations did not influence the toxicity of As(III) to either organism. Chlorella sp. CE-35 showed the ability to reduce As(V) to As(III), indicating a substantial influence of phytoplankton on As biogeochemistry in freshwater aquatic systems.

  14. Identification of Sporopollenin as the Outer Layer of Cell Wall in Microalga Chlorella protothecoides.

    PubMed

    He, Xi; Dai, Junbiao; Wu, Qingyu

    2016-01-01

    Chlorella protothecoides has been put forth as a promising candidate for commercial biodiesel production. However, the cost of biodiesel remains much higher than diesel from fossil fuel sources, partially due to the high costs of oil extraction from algae. Here, we identified the presence of a sporopollenin layer outside the polysaccharide cell wall; this was evaluated using transmission electron microscopy, 2-aminoethanol treatment, acetolysis, and Fourier Transform Infrared Spectroscopy. We also performed bioinformatics analysis of the genes of the C. protothecoides genome that are likely involved in sporopollenin synthesis, secretion, and translocation, and evaluated the expression of these genes via real-time PCR. We also found that that removal of this sporopollenin layer greatly improved the efficiency of oil extraction. PMID:27446068

  15. Identification of Sporopollenin as the Outer Layer of Cell Wall in Microalga Chlorella protothecoides

    PubMed Central

    He, Xi; Dai, Junbiao; Wu, Qingyu

    2016-01-01

    Chlorella protothecoides has been put forth as a promising candidate for commercial biodiesel production. However, the cost of biodiesel remains much higher than diesel from fossil fuel sources, partially due to the high costs of oil extraction from algae. Here, we identified the presence of a sporopollenin layer outside the polysaccharide cell wall; this was evaluated using transmission electron microscopy, 2-aminoethanol treatment, acetolysis, and Fourier Transform Infrared Spectroscopy. We also performed bioinformatics analysis of the genes of the C. protothecoides genome that are likely involved in sporopollenin synthesis, secretion, and translocation, and evaluated the expression of these genes via real-time PCR. We also found that that removal of this sporopollenin layer greatly improved the efficiency of oil extraction. PMID:27446068

  16. Isolation and purification of lutein from the microalga Chlorella vulgaris by extraction after saponification.

    PubMed

    Li, Hua-Bin; Jiang, Yue; Chen, Feng

    2002-02-27

    A simple and efficient method for the isolation and purification of lutein from the microalga Chlorella vulgaris was developed. Crude lutein was obtained by extraction with dichloromethane from the microalga after saponification. Partition values of lutein in the two-phase system of ethanol-water-dichloromethane at different ratios were measured by HPLC so as to assist the determination of an appropriate condition for washing water-soluble impurities in the crude lutein. Partition values of lutein in another two-phase system of ethanol-water-hexane at different ratios were also measured by HPLC for determining the condition for removing fat-soluble impurities. The water-soluble impurities in the crude lutein were removed by washing with 30% aqueous ethanol, and the fat-soluble impurities were removed by extraction with hexane. The final purity of lutein obtained was 90-98%, and the yield was 85-91%.

  17. Photosynthetic light reactions increase total lipid accumulation in carbon-supplemented batch cultures of Chlorella vulgaris.

    PubMed

    Woodworth, Benjamin D; Mead, Rebecca L; Nichols, Courtney N; Kolling, Derrick R J

    2015-03-01

    Microalgae are an attractive biofuel feedstock because of their high lipid to biomass ratios, lipid compositions that are suitable for biodiesel production, and the ability to grow on varied carbon sources. While algae can grow autotrophically, supplying an exogenous carbon source can increase growth rates and allow heterotrophic growth in the absence of light. Time course analyses of dextrose-supplemented Chlorella vulgaris batch cultures demonstrate that light availability directly influences growth rate, chlorophyll production, and total lipid accumulation. Parallel photomixotrophic and heterotrophic cultures grown to stationary phase reached the same amount of biomass, but total lipid content was higher for algae grown in the presence of light (an average of 1.90 mg/mL vs. 0.77 mg/mL over 5 days of stationary phase growth).

  18. Influence of organic matter generated by Chlorella vulgaris on five different modes of flocculation.

    PubMed

    Vandamme, Dries; Foubert, Imogen; Fraeye, Ilse; Muylaert, Koenraad

    2012-11-01

    Microalgae excrete relatively large amounts of algal organic matter (AOM) that may interfere with flocculation. The influence of AOM on flocculation of Chlorella vulgaris was studied using five different flocculation methods: aluminum sulfate, chitosan, cationic starch, pH-induced flocculation and electro-coagulation-flocculation (ECF). The presence of AOM was found to inhibit flocculation for all flocculation methods resulting in an increase of dosage demand. For pH-induced flocculation, the dosage required to achieve 85% flocculation increased only 2-fold when AOM was present, while for chitosan, this dosage increased 9-fold. For alum, ECF and cationic starch flocculation, the dosage increased 5-6-fold. Interference by AOM is an important parameter to consider in the assessment of flocculation-based harvesting of microalgae. PMID:23010213

  19. Cultivation of Chlorella vulgaris in dairy wastewater pretreated by UV irradiation and sodium hypochlorite.

    PubMed

    Qin, Lei; Shu, Qing; Wang, Zhongming; Shang, Changhua; Zhu, Shunni; Xu, Jingliang; Li, Rongqing; Zhu, Liandong; Yuan, Zhenhong

    2014-01-01

    There is potential in the utilization of microalgae for the purification of wastewater as well as recycling the resource in the wastewater to produce biodiesel. The large-scale cultivation of microalgae requires pretreatment of the wastewater to eliminate bacteria and protozoa. This procedure is costly and complex. In this study, two methods of pretreatment, UV irradiation, and sodium hypochlorite (NaClO), in various doses and concentrations, were tested in the dairy wastewater. Combining the efficiency of biodiesel production, we proposed to treat the dairy wastewater with NaClO in the concentration of 30 ppm. In this condition, The highest biomass productivity and lipid productivity of Chlorella vulgaris reached 0.450 g L(-1) day(-1) and 51 mg L(-1) day(-1) after a 4-day cultivation in the dairy wastewater, respectively. PMID:24142385

  20. Harvesting freshwater Chlorella vulgaris with flocculant derived from spent brewer's yeast.

    PubMed

    Prochazkova, Gita; Kastanek, Petr; Branyik, Tomas

    2015-02-01

    One of the key bottlenecks of the economically viable production of low added value microalgal products (food supplements, feed, biofuels) is the harvesting of cells from diluted culture medium. The main goals of this work were to prepare a novel flocculation agent based on spent brewer's yeast, a brewery by-product, and to test its harvesting efficiency on freshwater Chlorella vulgaris in different environments. The yeast was first autolyzed/hydrolyzed and subsequently chemically modified with 2-chloro-N,N-diethylethylamine hydrochloride (DEAE). Second, optimal dosage of modified spent yeast (MSY) flocculant for harvesting C. vulgaris was determined in culture media of various compositions. It was found that the absence of phosphorus ions decreased (0.4 mg MSY/g biomass), while the presence of algogenic organic matter (AOM) increased (51 mg MSY/g biomass) the required dosage of flocculant as compared to complete mineral medium with phosphorus and without AOM (12 mg MSY/g biomass). PMID:25479390

  1. Characterization of three Chlorella sorokiniana strains in anaerobic digested effluent from cattle manure.

    PubMed

    Kobayashi, Naoko; Noel, Eric A; Barnes, Austin; Watson, Andrea; Rosenberg, Julian N; Erickson, Galen; Oyler, George A

    2013-12-01

    Chlorella sorokiniana CS-01, UTEX 1230 and UTEX 2714 were maintained in 10% anaerobic digester effluent (ADE) from cattle manure digestion and compared with algal cultivation in Bold's Basal Medium (BBM). Biomass of CS-01 and UTEX 1230 in ADE produced similar or greater than 280mg/L after 21days in BBM, however, UTEX 2714 growth in ADE was suppressed by more than 50% demonstrating a significant species bias to synthetic compared to organic waste-based media. The highest accumulation of protein and starch was exhibited in UTEX 1230 in ADE yielding 34% and 23% ash free dry weight (AFDW), respectively, though fatty acid methyl ester total lipid measured less than 12% AFDW. Results suggest that biomass from UTEX 1230 in ADE may serve as a candidate alga and growth system combination sustainable for animal feed production considering high yields of protein, starch and low lipid accumulation. PMID:24185420

  2. N/sub 2/O evolution by green algae. [Chlorella; Scenedesmus; Coelastrum; Chlorococcum

    SciTech Connect

    Weathers, P.J.

    1984-12-01

    Nitrous oxide (N/sub 2/O) is an intermediate in denitrification and a by-product of both nitrification and dissimilatory nitrogen oxide reduction. The extent of the global source and pool of N/sub 2/O is uncertain and especially controversial in aquatic systems. Recognition of new, widespread biological sources of N/sub 2/O affects current theories of the global N/sub 2/O balance. Evidence is presented here that axenic cultures of Chlorella, Scenedesmus, Coelastrum, and Chlorococcum spp. evolve N/sub 2/O when grown on NO/sub 2//sup -/, showing that the Chlorophyceae are a source of N/sub 2/O in aquatic systems. 18 references, 2 tables.

  3. Mimic of superoxide dismutase activity protects Chlorella sorokiniana against the toxicity of sulfite

    SciTech Connect

    Rabinowitch, H.D.; Rosen, G.M.; Fridovich, I.

    1989-01-01

    The spin-trapping agent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) has been used to demonstrate the light-dependent production of O/sub 2/- by Chlorella sorokiniana. In the presence of SO/sub 3/= a light-dependent production of the sulfur trioxy anion radical (SO/sub 3/-.) could also be seen. A complex prepared by reacting desferrioxamine with MnO/sub 2/, which catalyzes the dismutation of O/sub 2/-, protected the alga against the toxicity of sulfite. The data suggest that SO/sub 2/ toxicity is at least partially due to the effects of sulfoxy-free radicals generated by the oxidation of SO3= by O/sub 2/-.

  4. Power generation enhancement in novel microbial carbon capture cells with immobilized Chlorella vulgaris

    NASA Astrophysics Data System (ADS)

    Zhou, Minghua; He, Huanhuan; Jin, Tao; Wang, Hongyu

    2012-09-01

    With the increasing concerns for global climate change, a sustainable, efficient and renewable energy production from wastewater is imperative. In this study, a novel microbial carbon capture cell (MCC), is constructed for the first time by the introduction of immobilized microalgae (Chlorella vulgaris) into the cathode chamber of microbial fuel cells (MFCs) to fulfill the zero discharge of carbon dioxide. This process can achieve an 84.8% COD removal, and simultaneously the maximum power density can reach 2485.35 mW m-3 at a current density of 7.9 A m-3 and the Coulombic efficiency is 9.40%, which are 88% and 57.7% greater than that with suspended C. vulgaris, respectively. These enhancements in performance demonstrate the feasibility of an economical and effective approach for the simultaneous wastewater treatment, electricity generation and biodiesel production from microalgae.

  5. Gases generated from simulated thermal degradation of autotrophic and heterotrophic chlorella

    SciTech Connect

    Qingyu Wu )

    1992-01-01

    The content of crude lipid in the cells of heterotrophic Chlorella protothecoides is 4.4 times as high as in the autotrophic algal cells. The gases thermally degraded from autotrophic cells at 200-300[degrees]C contain mainly CO[sub 2], while the heterotrophic algal cells produce hydrocarbon gas at a much higher rate than autotraophic algal cells. With the rise in temperature, both kinds of cells display a rapid drop in the acid/alkane ratio of the gas components and the ratio of ethane to ethylene increases regularly. Their ratio of normal and isomeric alkanes are all above 1. The study reveals that the actual potential of microplanktonic algae in producing oil and natural gas should be much greater than what people have recognized before.

  6. Regulation of starch and lipid accumulation in a microalga Chlorella sorokiniana.

    PubMed

    Li, Tingting; Gargouri, Mahmoud; Feng, Jie; Park, Jeong-Jin; Gao, Difeng; Miao, Chao; Dong, Tao; Gang, David R; Chen, Shulin

    2015-03-01

    Microalgae have attracted growing attention due to their potential in biofuel feedstock production. However, current understanding of the regulatory mechanisms for lipid biosynthesis and storage in microalgae is still limited. This study revealed that the microalga Chlorella sorokiniana showed sequential accumulation of starch and lipids. When nitrogen was replete and/or depleted over a short period, starch was the predominant carbon storage form with basal levels of lipid accumulation. After prolonged nitrogen depletion, lipid accumulation increased considerably, which was partially due to starch degradation, as well as the turnover of primary metabolites. Lipid accumulation is also strongly dependent on the linear electron flow of photosynthesis, peaking at lower light intensities. Collectively, this study reveals a relatively clear regulation pattern of starch and lipid accumulation that is basically controlled by nitrogen levels. The mixotrophic growth of C. sorokiniana shows promise for biofuel production in terms of lipid accumulation in the final biomass.

  7. The combined effect of bacteria and Chlorella vulgaris on the treatment of municipal wastewaters.

    PubMed

    He, P J; Mao, B; Lü, F; Shao, L M; Lee, D J; Chang, J S

    2013-10-01

    Impacts of Chlorella vulgaris with or without co-existing bacteria on the removal of nitrogen, phosphorus and organic matter from wastewaters were studied by comparing the wastewater treatment effects between an algae-bacteria consortium and a stand-alone algae system. In the algae-bacteria system, C.vulgaris played a dominant role in the removal of nitrogen and phosphorus, while bacteria removed most of the organic matter from the wastewater. When treating unsterilized wastewater, bacteria were found to inhibit the growth of algae at >231 mg/L dissolved organic carbon (DOC). Using the algae-bacteria consortium resulted in the removal of 97% NH4(+), 98% phosphorus and 26% DOC at a total nitrogen (TN) level of 29-174 mg/L. The reaction rate constant (k) values in sterilized and unsterilized wastewaters were 2.17 and 1.92 mg NH4(+)-N/(mg algal cell ·d), respectively.

  8. Uptake of Inorganic Carbon by Isolated Chloroplasts of the Unicellular Green Alga Chlorella ellipsoidea1

    PubMed Central

    Rotatore, Caterina; Colman, Brian

    1990-01-01

    Chloroplasts, isolated from protoplasts of the green alga, Chlorella ellipsoidea, were estimated to be 99% intact by the ferricyanide-reduction assay, and gave CO2 and PGA-dependent rates of O2 evolution of 64.5 to 150 micromoles per milligram of chlorophyll per hour, that is 30 to 70% of the photosynthetic activity of the parent cells. Intact chloroplasts showed no carbonic anhydrase activity, but it was detected in preparations of ruptured organelles. Rates of photosynthesis, measured in a closed system at pH 7.5, were twice the calculated rate of CO2 supply from the uncatalyzed dehydration of HCO3− indicating a direct uptake of bicarbonate by the intact chloroplasts. Mass spectrometric measurements of CO2 depletion from the medium on the illumination of chloroplasts indicate the lack of an active CO2 transport across the chloroplast envelope. PMID:16667662

  9. Simultaneously concentrating and pretreating of microalgae Chlorella spp. by three-phase partitioning.

    PubMed

    Li, Zhubo; Jiang, Feifei; Li, Ya; Zhang, Xu; Tan, Tianwei

    2013-12-01

    In this study, a recent simple separation technique, three-phase partitioning (TPP), was used for concentrating microalgae Chlorella spp. for the first time. More than 91.7% of the biomass precipitated in the interlayer of the system in 10 min. Temperature, initial concentration and ratio of ethanol to dipotassium hydrogen phosphate (DKP) were observed to negatively correlate with concentration factor while pH showed no significant influences. Using this method, biomass could be concentrated with much lower energy consumption and concentrated biomass could be conveniently collected. Besides, together with concentrating, TPP concentrated microalgae cells showed 26.3% increase in lipid extraction yield. Additionally, similarities in fatty acid profile indicated the avoidance of influence on lipid quality from chemicals. This study demonstrated the feasibility of TPP for microalgae biodiesel production. PMID:24121370

  10. Mixotrophic cultivation of Chlorella vulgaris using industrial dairy waste as organic carbon source.

    PubMed

    Abreu, Ana P; Fernandes, Bruno; Vicente, António A; Teixeira, José; Dragone, Giuliano

    2012-08-01

    Growth parameters and biochemical composition of the green microalga Chlorella vulgaris cultivated under different mixotrophic conditions were determined and compared to those obtained from a photoautotrophic control culture. Mixotrophic microalgae showed higher specific growth rate, final biomass concentration and productivities of lipids, starch and proteins than microalgae cultivated under photoautotrophic conditions. Moreover, supplementation of the inorganic culture medium with hydrolyzed cheese whey powder solution led to a significant improvement in microalgal biomass production and carbohydrate utilization when compared with the culture enriched with a mixture of pure glucose and galactose, due to the presence of growth promoting nutrients in cheese whey. Mixotrophic cultivation of C. vulgaris using the main dairy industry by-product could be considered a feasible alternative to reduce the costs of microalgal biomass production, since it does not require the addition of expensive carbohydrates to the culture medium. PMID:22705507

  11. Influence of growth phase on harvesting of Chlorella zofingiensis by dissolved air flotation.

    PubMed

    Zhang, Xuezhi; Amendola, Pasquale; Hewson, John C; Sommerfeld, Milton; Hu, Qiang

    2012-07-01

    The effects of changes in cellular characteristics and dissolved organic matter (DOM) on dissolved air flotation (DAF) harvesting of Chlorella zofingiensis at the different growth phases were studied. Harvesting efficiency increased with Al(3+) dosage and reached more than 90%, regardless of growth phases. In the absence of DOM, the ratio of Al(3+) dosage to surface functional group concentration determined the harvesting efficiency. DOM in the culture medium competed with algal cell surface functional groups for Al(3+), and more Al(3+) was required for cultures with DOM than for DOM-free cultures to achieve the same harvesting efficiency. As the culture aged, the increase of Al(3+) dosage due to increased DOM was less than the decrease of Al(3+) dosage associated with reduced cell surface functional groups, resulting in overall reduced demand for Al(3+). The interdependency of Al(3+) dosage and harvesting efficiency on concentrations of cell surface functional groups and DOM was successfully modeled. PMID:22541950

  12. Protease cell wall degradation of Chlorella vulgaris: effect on methane production.

    PubMed

    Mahdy, Ahmed; Mendez, Lara; Blanco, Saul; Ballesteros, Mercedes; González-Fernández, Cristina

    2014-11-01

    In order to optimize the enzymatic dosage and microalgae biomass loads subjected to enzymatic hydrolysis prior anaerobic digestion of Chlorella vulgaris, organic matter solubilisation and methane production were investigated. Experimental data using protease dosage of 0.585 AU g DW(-1) showed that increasing biomass loads up to 65 g L(-1) did not affect markedly the hydrolysis efficiency (51%). Enzymatically pretreated biomasses subjected to anaerobic digestion enhanced methane production by 50-70%. The attempt of decreasing the enzymatic dosages revealed diminished hydrolysis efficiency concomitantly with a decreased methane production enhancement. In agreement with the good results observed for organic matter conversion into biogas, total nitrogen mineralization was attained for enzymatically pretreated biomass. Despite the high protein content of the biomass and the biocatalyst used in the present study no ammonia inhibition was detected. PMID:25226058

  13. Multicellular group formation in response to predators in the alga Chlorella vulgaris.

    PubMed

    Fisher, R M; Bell, T; West, S A

    2016-03-01

    A key step in the evolution of multicellular organisms is the formation of cooperative multicellular groups. It has been suggested that predation pressure may promote multicellular group formation in some algae and bacteria, with cells forming groups to lower their chance of being eaten. We use the green alga Chlorella vulgaris and the protist Tetrahymena thermophila to test whether predation pressure can initiate the formation of colonies. We found that: (1) either predators or just predator exoproducts promote colony formation; (2) higher predator densities cause more colonies to form; and (3) colony formation in this system is facultative, with populations returning to being unicellular when the predation pressure is removed. These results provide empirical support for the hypothesis that predation pressure promotes multicellular group formation. The speed of the reversion of populations to unicellularity suggests that this response is due to phenotypic plasticity and not evolutionary change. PMID:26663204

  14. Size-dependent toxicity of silica nano-particles to Chlorella kessleri.

    PubMed

    Fujiwara, Kitao; Suematsu, Hitoshi; Kiyomiya, Emiko; Aoki, Motohide; Sato, Mamiko; Moritoki, Nobuko

    2008-08-01

    SiO(2) nano-particles were found to exhibit size-dependent toxicity toward the alga, Chlorella kessleri. Small SiO(2) nano-particles exhibit stronger toxicity: 50% inhibitory concentrations (IC(50)) value for 5 nm = 0.8 +/- 0.6%, 26 nm = 7.1 +/- 2.8%, and 78 nm = 9.1 +/- 4.7%. Enlargement of the cell body was observed by flow cytometry, which is due to the presence of structures that obstructed cell division. Optical and transmission microscopes were used to observe coagulated cells with incomplete division. Although the physiological effect of SiO(2) nano-particles was not clear, SiO(2) nano-particles are toxic, at least for algae in aquatic media. Under the transmission electron microscope, several amorphous structures appeared in the cells that were exposed to 5-nm silica nano-particles. PMID:18584432

  15. The Chlorella killed by pulsed electrical discharge in liquid with two different reactors

    NASA Astrophysics Data System (ADS)

    Gao, Z. Y.; Sun, B.; Yan, Z. Y.; Zhu, X. M.; Liu, H.; Song, Y. J.; Sato, M.

    2013-03-01

    The application of pulsed high-voltage discharge in liquid has attracted wide attention as an effective water treatment. In this paper, two different liquid high-voltage discharge systems were constructed with plate-hole-plate and needle-plate electrode structures, and the inactivation behaviors of Chlorella were studied in the two reactors. The results show that the killing rates of algae in both reactors all increased significantly with increasing discharge voltage and the killing rates were intensely related to discharge power, instantaneous power and single pulse input energy. Furthermore, the inactivation effect in needle-plate reactor was superior to that in plate-hole-plate reactor under the same experimental conditions.

  16. Lipid accumulation from pinewood pyrolysates by Rhodosporidium diobovatum and Chlorella vulgaris for biodiesel production.

    PubMed

    Luque, Luis; Orr, Valerie C A; Chen, Sean; Westerhof, Roel; Oudenhoven, Stijn; Rossum, Guus van; Kersten, Sascha; Berruti, Franco; Rehmann, Lars

    2016-08-01

    This study evaluated the suitability of pinewood pyrolysates as a carbon source for lipid production and cultivation of the oleaginous yeast Rhodosporidium diobovatum and the microalgae Chlorella vulgaris. Thermal decomposition of pinewood and fractional condensation were used to obtain an oil rich in levoglucosan which was upgraded to glucose by acid hydrolysis. Blending of pyrolytic sugars with pure glucose in both nitrogen rich and nitrogen limited conditions was studied for R. diobovatum, and under nitrogen limited conditions for C. vulgaris. Glucose consumption rate decreased with increasing proportions of pyrolytic sugars increasing cultivation time. While R. diobovatum was capable of growth in 100% (v/v) pyrolytic sugars, C. vulgaris growth declined rapidly in blends greater than 20% (v/v) until no growth was detected in blends >40%. Finally, the effects of pyrolysis sugars on lipid composition was evaluated and biodiesel fuel properties were estimated based on the lipid profiles. PMID:27208736

  17. Proteomic analysis of Chlorella vulgaris: Potential targets for enhanced lipid accumulation

    SciTech Connect

    Guarnieri, Michael T.; Nag, Ambarish; Yang, Shihui; Pienkos, Philip T.

    2013-11-01

    Oleaginous microalgae are capable of producing large quantities of fatty acids and triacylglycerides. As such, they are promising feedstocks for the production of biofuels and bioproducts. Genetic strain-engineering strategies offer a means to accelerate the commercialization of algal biofuels by improving the rate and total accumulation of microalgal lipids. However, the industrial potential of these organisms remains to be met, largely due to the incomplete knowledgebase surrounding the mechanisms governing the induction of algal lipid biosynthesis. Such strategies require further elucidation of genes and gene products controlling algal lipid accumulation. In this study, we have set out to examine these mechanisms and identify novel strain-engineering targets in the oleaginous microalga, Chlorella vulgaris. Comparative shotgun proteomic analyses have identified a number of novel targets, including previously unidentified transcription factors and proteins involved in cell signaling and cell cycle regulation. These results lay the foundation for strain-improvement strategies and demonstrate the power of translational proteomic analysis.

  18. First evidence of bioflocculant from Shinella albus with flocculation activity on harvesting of Chlorella vulgaris biomass.

    PubMed

    Li, Yi; Xu, Yanting; Liu, Lei; Jiang, Xiaobing; Zhang, Kun; Zheng, Tianling; Wang, Hailei

    2016-10-01

    Bioflocculant from Shinella albus xn-1 could be used to harvest energy-producing microalga Chlorella vulgaris biomass for the first time. In this study, we investigated the flocculation activity and mode of strain xn-1, the characteristics of bioflocculant, the effect of flocculation conditions and optimized the flocculation efficiency. The results indicated that strain xn-1 exhibited flocculation activity through secreting bioflocculant; the bioflocculant with high thermal stability, pH stability and low molecular weight was proved to be not protein and polysaccharide, and flocculation active component was confirmed to contain triple bond and cumulated double bonds; algal pH, temperature and metal ions showed great impacts on the flocculation efficiency of bioflocculant; the maximum flocculation activity of bioflocculant reached 85.65% after the response surface optimization. According to the results, the bioflocculant from S. albus xn-1 could be a good potential in applications for high-efficiency harvesting of microalgae.

  19. Effect of moderate static electric field on the growth and metabolism of Chlorella vulgaris.

    PubMed

    Nezammahalleh, Hassan; Ghanati, Faezeh; Adams, Thomas A; Nosrati, Mohsen; Shojaosadati, Seyed Abbas

    2016-10-01

    An electric field (EF) generator device was fabricated and applied to the treatment of Chlorella vulgaris ISC33 at three distinct concentrations before cultivation. The EF of moderate intensity (2.7kVcm(-1)) has a hormetic effect on algal growth. The highest growth stimulation of 51% was observed after 50min treatment of 0.4gL(-1) algal suspension. The influence of EF on the system was then studied from both theoretical and experimental perspectives. The growth rate increased with treatment time up to a maximum because of improved membrane permeability, and then declined afterwards due to peroxide accumulation in the medium. The contents of chlorophylls, carotenoids, soluble carbohydrates, lipids, and proteins were also measured to understand possible changes on algal metabolism. The EF treatment of algal suspension has no observable effect on the cell metabolism while both algal growth and metabolism was significantly affected by the inoculum size.

  20. Change in Photosystem II Photochemistry During Algal Growth Phases of Chlorella vulgaris and Scenedesmus obliquus.

    PubMed

    Oukarroum, Abdallah

    2016-06-01

    Sensitivity of photosynthetic processes towards environmental stress is used as a bioanalytical tool to evaluate the responses of aquatic plants to a changing environment. In this paper, change of biomass density, chlorophyll a fluorescence and photosynthetic parameters during growth phases of two microalgae Chlorella vulgaris and Scenedesmus obliquus were studied. The photosynthetic growth behaviour changed significantly with cell age and algae species. During the exponential phase of growth, the photosynthesis capacity reached its maximum and decreased in ageing algal culture during stationary phase. In conclusion, the chlorophyll a fluorescence OJIP method and the derived fluorescence parameters would be an accurate method for obtaining information on maximum photosynthetic capacities and monitoring algal cell growth. This will contribute to more understanding, for example, of toxic actions of pollutants in microalgae test. PMID:26868257

  1. [Studies on the light-induced reversible xanthophyll-conversions in Chlorella and spinach leaves].

    PubMed

    Hager, A

    1967-06-01

    1. Using new methods in thin-layer chromatography, experiments were carried out to prove the light-induced changes in the quantity of various xanthophylls in Chlorella and spinach leaves. The probable connection of these interconversions to electron transport in photosynthesis was demonstrated. 2. The kinetics of these xanthophyll conversions were investigated during strong illumination and in the succeeding dark period (Chlorella). Already after illumination of 1 min one can detect a decrease of the di-epoxide xanthophyll violaxanthin and a corresponding increase of the epoxide-free zeaxanthin. The intermediate of this interconversion is the mono-epoxide antheraxanthin. Neoxanthin exhibits no change in concentration under the given light intensity and an illumination time of 60 min and more; the same result can be observed with the other carotenoids (α-carotene, β-carotene, lutein, lutein-5,6-epoxyd) and the chlorophylls a and b. 3. The light-induced formation of zeaxanthin is not correlated with those pigment interconversions which are photooxidative in their nature and which may be detected only after long illuminations. However, by using damaged, e.g., briefly heated Chlorella cells, a photooxidative-induced decrease of carotenes and chlorophyll a and a smaller decrease of xanthophylls and chlorophyll b could already be demonstrated after illumination of 15 min. In this case the ratio xanthophylls/ carotenes increases. 4. The transformation violaxanthin → antheraxanthin → zeaxanthin ("forward-reaction") is induced not only by an illumination with white light (point 2) but also with red light (>600 nm); that means the reaction proceeds at a wavelength which cannot be absorbed by the xanthophylls themselves. Chlorophyll acts as light-acceptor. 5. The "forward-reaction" does not proceed after the cells have been heated for a short time. The presence of inhibitors of light-reaction II in photosynthesis such as o-phenanthroline, hydroxylamine and DCMU entirely

  2. Biodiesel production from hydrolysate of Cyperus esculentus waste by Chlorella vulgaris.

    PubMed

    Wang, Wenrui; Zhou, Wenwen; Liu, Jing; Li, Yonghong; Zhang, Yongkui

    2013-05-01

    To reduce the cost of algal-based biodiesel, a waste material from oil industry, Cyperus esculentus waste, was used as the carbon source of the oleaginous microalgae Chlorella vulgaris. It demonstrated that C. vulgaris grew better in C. esculentus waste hydrolysate (CEWH(1)) than in glucose medium under the same reducing sugar concentration. CEWH concentration influenced the cell growth and lipid production significantly. The maximum lipid productivity 438.85 mg l(-1) d(-1) was achieved at 40 g l(-1). Fed-batch culture was performed to further enhance lipid production. The maximum biomass, lipid content and lipid productivity were 20.75 g l(-1), 36.52%, and 621.53 mg l(-1) d(-1), respectively. The produced biodiesel was analyzed by GC-MS and the results suggested that lipids produced from CEWH could be a potential feedstock for biodiesel production. PMID:23548401

  3. Effect of nitrogen source on growth and lipid accumulation in Scenedesmus abundans and Chlorella ellipsoidea.

    PubMed

    González-Garcinuño, Álvaro; Tabernero, Antonio; Sánchez-Álvarez, José Ma; Martin del Valle, Eva M; Galán, Miguel A

    2014-12-01

    Discovering microalgae strains containing a high lipid yield and adequate fatty acid composition is becoming a crucial fact in algae-oil factories. In this study, two unknown strains, named Scenedesmus abundans and Chlorella ellipsoidea, have been tested for their response to different nitrogen sources, in order to determine its influence in the production of lipids. For S. abundans, autotrophic culture with ammonium nitrate offers the maximum lipid yield, obtaining up to 3.55 mg L(-1) d(-1). For C. ellipsoidea, heterotrophic culture with ammonium nitrate has been shown to be the best condition, reaching a lipid production of 9.27 mg L(-1) d(-1). Moreover, fatty acid composition obtained from these cultures meets international biodiesel standards with an important amount of C18:1, achieving 70% of total fatty acids and thus representing a potential use of these two strains at an industrial scale. PMID:25310870

  4. Evaluation of sample extraction methods for proteomics analysis of green algae Chlorella vulgaris.

    PubMed

    Gao, Yan; Lim, Teck Kwang; Lin, Qingsong; Li, Sam Fong Yau

    2016-05-01

    Many protein extraction methods have been developed for plant proteome analysis but information is limited on the optimal protein extraction method from algae species. This study evaluated four protein extraction methods, i.e. direct lysis buffer method, TCA-acetone method, phenol method, and phenol/TCA-acetone method, using green algae Chlorella vulgaris for proteome analysis. The data presented showed that phenol/TCA-acetone method was superior to the other three tested methods with regards to shotgun proteomics. Proteins identified using shotgun proteomics were validated using sequential window acquisition of all theoretical fragment-ion spectra (SWATH) technique. Additionally, SWATH provides protein quantitation information from different methods and protein abundance using different protein extraction methods was evaluated. These results highlight the importance of green algae protein extraction method for subsequent MS analysis and identification.

  5. Effect of moderate static electric field on the growth and metabolism of Chlorella vulgaris.

    PubMed

    Nezammahalleh, Hassan; Ghanati, Faezeh; Adams, Thomas A; Nosrati, Mohsen; Shojaosadati, Seyed Abbas

    2016-10-01

    An electric field (EF) generator device was fabricated and applied to the treatment of Chlorella vulgaris ISC33 at three distinct concentrations before cultivation. The EF of moderate intensity (2.7kVcm(-1)) has a hormetic effect on algal growth. The highest growth stimulation of 51% was observed after 50min treatment of 0.4gL(-1) algal suspension. The influence of EF on the system was then studied from both theoretical and experimental perspectives. The growth rate increased with treatment time up to a maximum because of improved membrane permeability, and then declined afterwards due to peroxide accumulation in the medium. The contents of chlorophylls, carotenoids, soluble carbohydrates, lipids, and proteins were also measured to understand possible changes on algal metabolism. The EF treatment of algal suspension has no observable effect on the cell metabolism while both algal growth and metabolism was significantly affected by the inoculum size. PMID:27420157

  6. Influence of organic matter generated by Chlorella vulgaris on five different modes of flocculation.

    PubMed

    Vandamme, Dries; Foubert, Imogen; Fraeye, Ilse; Muylaert, Koenraad

    2012-11-01

    Microalgae excrete relatively large amounts of algal organic matter (AOM) that may interfere with flocculation. The influence of AOM on flocculation of Chlorella vulgaris was studied using five different flocculation methods: aluminum sulfate, chitosan, cationic starch, pH-induced flocculation and electro-coagulation-flocculation (ECF). The presence of AOM was found to inhibit flocculation for all flocculation methods resulting in an increase of dosage demand. For pH-induced flocculation, the dosage required to achieve 85% flocculation increased only 2-fold when AOM was present, while for chitosan, this dosage increased 9-fold. For alum, ECF and cationic starch flocculation, the dosage increased 5-6-fold. Interference by AOM is an important parameter to consider in the assessment of flocculation-based harvesting of microalgae.

  7. First evidence of bioflocculant from Shinella albus with flocculation activity on harvesting of Chlorella vulgaris biomass.

    PubMed

    Li, Yi; Xu, Yanting; Liu, Lei; Jiang, Xiaobing; Zhang, Kun; Zheng, Tianling; Wang, Hailei

    2016-10-01

    Bioflocculant from Shinella albus xn-1 could be used to harvest energy-producing microalga Chlorella vulgaris biomass for the first time. In this study, we investigated the flocculation activity and mode of strain xn-1, the characteristics of bioflocculant, the effect of flocculation conditions and optimized the flocculation efficiency. The results indicated that strain xn-1 exhibited flocculation activity through secreting bioflocculant; the bioflocculant with high thermal stability, pH stability and low molecular weight was proved to be not protein and polysaccharide, and flocculation active component was confirmed to contain triple bond and cumulated double bonds; algal pH, temperature and metal ions showed great impacts on the flocculation efficiency of bioflocculant; the maximum flocculation activity of bioflocculant reached 85.65% after the response surface optimization. According to the results, the bioflocculant from S. albus xn-1 could be a good potential in applications for high-efficiency harvesting of microalgae. PMID:27423548

  8. Osmoregulation in the Extremely Euryhaline Marine Micro-Alga Chlorella autotrophica1

    PubMed Central

    Ahmad, Iftikhar; Hellebust, Johan A.

    1984-01-01

    Chlorella autotrophica (Clone 580) grows over the external salinity range of 1 to 400% artificial sea water (ASW), can photosynthesize over the range from 1 to 600% ASW, and survives the complete evaporation of seawater. The alga grown at high salinities shows an increase in cell volume and a small decrease in cell water content. Measurements of ion content were made by neutron activation analysis on cells washed in isoosmotic sorbitol solutions which contained a few millimolar of major ions to prevent ion leakage. Cells grown at various ASW concentrations contain large quantities of sodium, potassium, and chloride ions. Measurements of cations associated with cell wall and intracellular macromolecules were made to determine intracellular concentration of free ions. The proline content of cells increases in response to increases in external salinity. Cells in 300% ASW contain 1500 to 1600 millimolar proline. PMID:16663495

  9. Simultaneously concentrating and pretreating of microalgae Chlorella spp. by three-phase partitioning.

    PubMed

    Li, Zhubo; Jiang, Feifei; Li, Ya; Zhang, Xu; Tan, Tianwei

    2013-12-01

    In this study, a recent simple separation technique, three-phase partitioning (TPP), was used for concentrating microalgae Chlorella spp. for the first time. More than 91.7% of the biomass precipitated in the interlayer of the system in 10 min. Temperature, initial concentration and ratio of ethanol to dipotassium hydrogen phosphate (DKP) were observed to negatively correlate with concentration factor while pH showed no significant influences. Using this method, biomass could be concentrated with much lower energy consumption and concentrated biomass could be conveniently collected. Besides, together with concentrating, TPP concentrated microalgae cells showed 26.3% increase in lipid extraction yield. Additionally, similarities in fatty acid profile indicated the avoidance of influence on lipid quality from chemicals. This study demonstrated the feasibility of TPP for microalgae biodiesel production.

  10. Protease cell wall degradation of Chlorella vulgaris: effect on methane production.

    PubMed

    Mahdy, Ahmed; Mendez, Lara; Blanco, Saul; Ballesteros, Mercedes; González-Fernández, Cristina

    2014-11-01

    In order to optimize the enzymatic dosage and microalgae biomass loads subjected to enzymatic hydrolysis prior anaerobic digestion of Chlorella vulgaris, organic matter solubilisation and methane production were investigated. Experimental data using protease dosage of 0.585 AU g DW(-1) showed that increasing biomass loads up to 65 g L(-1) did not affect markedly the hydrolysis efficiency (51%). Enzymatically pretreated biomasses subjected to anaerobic digestion enhanced methane production by 50-70%. The attempt of decreasing the enzymatic dosages revealed diminished hydrolysis efficiency concomitantly with a decreased methane production enhancement. In agreement with the good results observed for organic matter conversion into biogas, total nitrogen mineralization was attained for enzymatically pretreated biomass. Despite the high protein content of the biomass and the biocatalyst used in the present study no ammonia inhibition was detected.

  11. Mild pressure induces rapid accumulation of neutral lipid (triacylglycerol) in Chlorella spp.

    PubMed

    Praveenkumar, Ramasamy; Kim, Bohwa; Lee, Jiye; Vijayan, Durairaj; Lee, Kyubock; Nam, Bora; Jeon, Sang Goo; Kim, Dong-Myung; Oh, You-Kwan

    2016-11-01

    Effective enhancement of neutral lipid (especially triacylglycerol, TAG) content in microalgae is an important issue for commercialization of microalgal biorefineries. Pressure is a key physical factor affecting the morphological, physiological, and biochemical behaviors of organisms. In this paper, we report a new stress-based method for induction of TAG accumulation in microalgae (specifically, Chlorella sp. KR-1 and Ch. sp. AG20150) by very-short-duration application of mild pressure. Pressure treatments of 10-15bar for 2h resulted in a considerable, ∼55% improvement of the 10-100g/Lcells' TAG contents compared with the untreated control. The post-pressure-treatment increase of cytoplasmic TAG granules was further confirmed by transmission electron microscopy (TEM). Notwithstanding the increased TAG content, the total lipid content was not changed by pressurization, implying that pressure stress possibly induces rapid remodeling/transformation of algal lipids rather than de novo biosynthesis of TAG. PMID:27634024

  12. High-productivity lipid production using mixed trophic state cultivation of Auxenochlorella (Chlorella) protothecoides.

    PubMed

    Rismani-Yazdi, Hamid; Hampel, Kristin H; Lane, Christopher D; Kessler, Ben A; White, Nicholas M; Moats, Kenneth M; Thomas Allnutt, F C

    2015-04-01

    A mixed trophic state production process for algal lipids for use as feedstock for renewable biofuel production was developed and deployed at subpilot scale using a green microalga, Auxenochlorella (Chlorella) protothecoides. The process is composed of two separate stages: (1) the photoautotrophic stage, focused on biomass production in open ponds, and (2) the heterotrophic stage focused on lipid production and accumulation in aerobic bioreactors using fixed carbon substrates (e.g., sugar). The process achieved biomass and lipid productivities of 0.5 and 0.27 g/L/h that were, respectively, over 250 and 670 times higher than those obtained from the photoautotrophic cultivation stage. The biomass oil content (over 60% w/DCW) following the two-stage process was predominantly monounsaturated fatty acids (~82%) and largely free of contaminating pigments that is more suitable for biodiesel production than photosynthetically generated lipid. Similar process performances were obtained using cassava hydrolysate as an alternative feedstock to glucose.

  13. Energetic response of Chlorella vulgaris to alpha radiation and PCB stress

    SciTech Connect

    Schaffer, S.A.

    1982-01-01

    This research project has evaluated the bioenergetic response of the green alga Chlorella vulgaris following acute exposure to either the physical stress of radiation or the chemical stress of PCBs. After exposure, changes in survival or growth, adenylate pools (ATP, ADP, and AMP), CO/sub 2/ fixation and oxygen evolution and uptake were measured. By employing anaerobic conditions, or the electron transport inhibitor DCMU or dark conditions separately and in specific combinations, this study evaluated the response of three separate algal ATP producing mechanisms (respiration, total and cyclic photophosphorylation) to alpha radiation or PCB. The use of the adenylate energy charge ratio as an indicator of stress was also evaluated. The results of the radiation experiments indicated that alpha particle exposure between 25 to 275 rads caused a one-hour latent demand for ATP due to radioinduced DNA repair. In order to compensate for this ATP demand, nonessential utilization of ATP was decreased by slowing the rate of carbon fixation. The results also suggest that use of radiation as a tool to study algal physiology. The data obtained from the PCB experiments again showed each phosphorylation mechanism to be insensitive to 10, 100 and 200 ppm Aroclor 1254 exposures. Data suggest, however, that PCBs caused an increased photosynthetic rate, and total adenylate pool with decreased growth. The use of the adenylate energy charge ratio as a stress indicator was assessed. Because this ratio did not fluctuate at doses of radiation or PCBs that caused reduced survival and growth rates, this study concluded that for Chlorella the adenylate energy charge ration was a poor indicator of sublethal stress.

  14. Sustainable Hydrogen Photoproduction by Phosphorus-Deprived Marine Green Microalgae Chlorella sp.

    PubMed Central

    Batyrova, Khorcheska; Gavrisheva, Anastasia; Ivanova, Elena; Liu, Jianguo; Tsygankov, Anatoly

    2015-01-01

    Previously it has been shown that green microalga Chlamydomonas reinhardtii is capable of prolonged H2 photoproduction when deprived of sulfur. In addition to sulfur deprivation (-S), sustained H2 photoproduction in C. reinhardtii cultures can be achieved under phosphorus-deprived (-P) conditions. Similar to sulfur deprivation, phosphorus deprivation limits O2 evolving activity in algal cells and causes other metabolic changes that are favorable for H2 photoproduction. Although significant advances in H2 photoproduction have recently been realized in fresh water microalgae, relatively few studies have focused on H2 production in marine green microalgae. In the present study phosphorus deprivation was applied for hydrogen production in marine green microalgae Chlorella sp., where sulfur deprivation is impossible due to a high concentration of sulfates in the sea water. Since resources of fresh water on earth are limited, the possibility of hydrogen production in seawater is more attractive. In order to achieve H2 photoproduction in P-deprived marine green microalgae Chlorella sp., the dilution approach was applied. Cultures diluted to about 0.5–1.8 mg Chl·L−1 in the beginning of P-deprivation were able to establish anaerobiosis, after the initial growth period, where cells utilize intracellular phosphorus, with subsequent transition to H2 photoproduction stage. It appears that marine microalgae during P-deprivation passed the same stages of adaptation as fresh water microalgae. The presence of inorganic carbon was essential for starch accumulation and subsequent hydrogen production by microalgae. The H2 accumulation was up to 40 mL H2 gas per 1iter of the culture, which is comparable to that obtained in P-deprived C. reinhardtii culture. PMID:25629229

  15. Sustainable hydrogen photoproduction by phosphorus-deprived marine green microalgae Chlorella sp.

    PubMed

    Batyrova, Khorcheska; Gavrisheva, Anastasia; Ivanova, Elena; Liu, Jianguo; Tsygankov, Anatoly

    2015-01-01

    Previously it has been shown that green microalga Chlamydomonas reinhardtii is capable of prolonged H2 photoproduction when deprived of sulfur. In addition to sulfur deprivation (-S), sustained H2 photoproduction in C. reinhardtii cultures can be achieved under phosphorus-deprived (-P) conditions. Similar to sulfur deprivation, phosphorus deprivation limits O2 evolving activity in algal cells and causes other metabolic changes that are favorable for H2 photoproduction. Although significant advances in H2 photoproduction have recently been realized in fresh water microalgae, relatively few studies have focused on H2 production in marine green microalgae. In the present study phosphorus deprivation was applied for hydrogen production in marine green microalgae Chlorella sp., where sulfur deprivation is impossible due to a high concentration of sulfates in the sea water. Since resources of fresh water on earth are limited, the possibility of hydrogen production in seawater is more attractive. In order to achieve H2 photoproduction in P-deprived marine green microalgae Chlorella sp., the dilution approach was applied. Cultures diluted to about 0.5-1.8 mg Chl·L-1 in the beginning of P-deprivation were able to establish anaerobiosis, after the initial growth period, where cells utilize intracellular phosphorus, with subsequent transition to H2 photoproduction stage. It appears that marine microalgae during P-deprivation passed the same stages of adaptation as fresh water microalgae. The presence of inorganic carbon was essential for starch accumulation and subsequent hydrogen production by microalgae. The H2 accumulation was up to 40 mL H2 gas per 1iter of the culture, which is comparable to that obtained in P-deprived C. reinhardtii culture. PMID:25629229

  16. [Mechanisms of 232Th effects on Chlorella vulgaris Beljer and modifications of it's toxic effect with caffeine and buthionine sulfoximine].

    PubMed

    Evseeva, T I; Maĭstrenko, T A; Geras'kin, S A; Belykh, E S

    2006-01-01

    232Th effects and its modifications with caffeine and D, L-buthionine-(S, R)-sulphoximine in Chlorella vulgaris Beijer cells was studied with use an optical density measure after 24 hours growth. Was shown relationship between concentration and toxic effect that is nonlinear and characterized with three parts different in induced damages level. In the first concentration range (0.001-1.551 micromol/l) chlorella growth parameters don't significantly differ from control ones. In the second one (1.724-3.017 micromol/1) statistically significant increase of optical density is but the effect does not dependent on 232Th concentration. The 232Th concentration (>3.448 micromol/l) increase the monotonous decrease in optical density was observed. The main role in 232Th toxic effect decrease make processes of DNA reparation, but not free radical scavenging with glutathione.

  17. Purification and photobiochemical profile of photosystem 1 from a high-salt tolerant, oleaginous Chlorella (Trebouxiophycaea, Chlorophyta).

    PubMed

    McConnell, Michael D; Lowry, David; Rowan, Troy N; van Dijk, Karin; Redding, Kevin E

    2015-06-01

    The eukaryotic green alga Chlamydomonas reinhardtii has been studied extensively within the biofuel industry as a model organism, as researchers look towards algae to provide chemical feedstocks (i.e., lipids) for the production of liquid transportation fuels. C. reinhardtii, however, is unsuitable for high-level production of such precursors due to its relatively poor lipid accumulation and fresh-water demand. In this study we offer insight into the primary light harvesting and electron transfer reactions that occur during phototropic growth in a high-salt tolerant strain of Chlorella (a novel strain introduced here as NE1401), a single-celled eukaryotic algae also in the phylum Chlorophyta. Under nutrient starvation many eukaryotic algae increase dramatically the amount of lipids stored in lipid bodies within their cell interiors. Microscopy and lipid analyses indicate that Chlorella sp. NE1401 may become a superior candidate for algal biofuels production. We have purified highly active Photosystem 1 (PS1) complexes to study in vitro, so that we may understand further the photobiochemisty of this promising biofuel producer and how its characteristics compare and contrast with that of the better understood C. reinhardtii. Our findings suggest that the PS1 complex from Chlorella sp. NE1401 demonstrates similar characteristics to that of C. reinhardtii with respect to light-harvesting and electron transfer reactions. We also illustrate that the relative extent of the light state transition performed by Chlorella sp. NE1401 is smaller compared to C. reinhardtii, although they are triggered by the same dynamic light stresses.

  18. Impact of algal organic matter released from Microcystis aeruginosa and Chlorella sp. on the fouling of a ceramic microfiltration membrane.

    PubMed

    Zhang, Xiaolei; Devanadera, Ma Catriona E; Roddick, Felicity A; Fan, Linhua; Dalida, Maria Lourdes P

    2016-10-15

    Algal blooms lead to the secretion of algal organic matter (AOM) from different algal species into water treatment systems, and there is very limited information regarding the impact of AOM from different species on the fouling of ceramic microfiltration (MF) membranes. The impact of soluble AOM released from Microcystis aeruginosa and Chlorella sp. separately and together in feedwater on the fouling of a tubular ceramic microfiltration membrane (alumina, 0.1 μm) was studied at lab scale. Multi-cycle MF tests operated in constant pressure mode showed that the AOM (3 mg DOC L(-1)) extracted from the cultures of the two algae in early log phase of growth (12 days) resulted in less flux decline compared with the AOM from stationary phase (35 days), due to the latter containing significantly greater amounts of high fouling potential components (protein and humic-like substances). The AOM released from Chlorella sp. at stationary phase led to considerably greater flux decline and irreversible fouling resistance compared with that from M. aeruginosa. The mixture of the AOM (1:1, 3 mg DOC L(-1)) from the two algal species showed more similar flux decline and irreversible fouling resistance to the AOM from M. aeruginosa than Chlorella sp. This was due to the characteristics of the AOM mixture being more similar to those for M. aeruginosa than Chlorella sp. The extent of the flux decline for the AOM mixture after conventional coagulation with aluminium chlorohydrate or alum was reduced by 70%. PMID:27486951

  19. Light intensity and N/P nutrient affect the accumulation of lipid and unsaturated fatty acids by Chlorella sp.

    PubMed

    Guo, Xiaoyi; Su, Gaomin; Li, Zheng; Chang, Jingyu; Zeng, Xianhai; Sun, Yong; Lu, Yinghua; Lin, Lu

    2015-09-01

    In this study, different light intensities (80, 160, 240 and 320 μmol/m(2) s) and various mediums including control medium (CM), N/P rich medium (NPM), N rich medium (NM), and P rich medium (PM) were applied for cultivation of Chlorella sp. It was revealed that cultivation of Chlorella sp. in CM under the light intensity of 320 μmol/m(2) s led to a lipid content up to 30% enhancement, which was higher than the results of other cases. A rather high unsaturated fatty acid (UFA) content of 7.5% and unsaturated fatty acid/total fatty acid (UFA/TFA) ratio of 0.73 were obtained under 320 μmol/m(2) s in CM, indicating that the CM-320 system was applicable for the generation of UFA. Moreover, Chlorella sp. cultivated in PM under 320 μmol/m(2) s provided higher TFA content (7.3%), which was appropriate for biofuel production.

  20. Improving high carbon dioxide tolerance and carbon dioxide fixation capability of Chlorella sp. by adaptive laboratory evolution.

    PubMed

    Li, Dengjin; Wang, Liang; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

    2015-06-01

    CO2 capture by microalgae is a promising method to reduce greenhouse gas emissions. It is critical to construct a highly efficient way to obtain a microalgal strain tolerant to high CO2 concentrations with high CO2 fixation capability. In this study, two evolved Chlorella sp. strains, AE10 and AE20 were obtained after 31 cycles of adaptive laboratory evolution (ALE) under 10% and 20% CO2, respectively. Both of them grew rapidly in 30% CO2 and the maximal biomass concentration of AE10 was 3.68±0.08g/L, which was 1.22 and 2.94 times to those of AE20 and original strain, respectively. The chlorophyll contents of AE10 and AE20 were significantly higher than those of the original one under 1-30% CO2. The influences of ALE process on biochemical compositions of Chlorella cells were also investigated. This study proved that ALE was an effective approach to improve high CO2 tolerance of Chlorella sp.

  1. Isolation and characterization of hardening-induced proteins in Chlorella vulgaris C-27: identification of late embryogenesis abundant proteins.

    PubMed

    Honjoh, K; Yoshimoto, M; Joh, T; Kajiwara, T; Miyamoto, T; Hatano, S

    1995-12-01

    Hardening-induced soluble proteins of Chlorella vulgaris Beijerink IAM C-27 (formerly Chlorella ellipsoidea Gerneck IAM C-27) were isolated and purified by two-dimensional high-performance liquid chromatography (2D-HPLC) on an anion-exchange column, with subsequent reversed-phase chromatography. Some of the proteins were resolved by SDS-PAGE, characterized by amino-terminal sequencing and identified by searching for homologies in databases. Separation of the soluble proteins during the hardening of Chlorella by a combination of 2D-HPLC and SDS-PAGE revealed that at least 31 proteins were induced or increased in abundance. Of particular interest was the induction after 12 h of a 10-kDa protein with the amino-terminal amino acid sequence AGNKPITEQISDAVGAAGQKVG and the induction after 6 h of a 14-kDa protein with the amino-terminal sequence ALGEESLGDKAKNAFEDAKDAVKDAAGNVKEAV. The amino-terminal sequences of these proteins indicated that they were homologous to late embryogenesis abundant (LEA) proteins. Furthermore, the level of a 22-kDa protein also increased after 12 h. The amino-terminal sequence of this protein, AAPLVGGPAPDFTAAAVFD, indicated that it was homologous to thioredoxin peroxidase. PMID:8589927

  2. Chlorella for protein and biofuels: from strain selection to outdoor cultivation in a Green Wall Panel photobioreactor

    PubMed Central

    2014-01-01

    Background Chlorella is one of the few microalgae employed for human consumption. It typically has a high protein content, but it can also accumulate high amounts of lipids or carbohydrates under stress conditions and, for this reason, it is of interest in the production of biofuels. High production costs and energy consumption are associated with its cultivation. This work describes a strategy to reduce costs and environmental impact of Chlorella biomass production for food, biofuels and other applications. Results The growth of four Chlorella strains, selected after a laboratory screening, was investigated outdoors in a low-cost 0.25 m2 GWP-II photobioreactor. The capacity of the selected strains to grow at high temperature was tested. On the basis of these results, in the nitrogen starvation trials the culture was cooled only when the temperature exceeded 40°C to allow for significant energy savings, and performed in a seawater-based medium to reduce the freshwater footprint. Under nutrient sufficiency, strain CH2 was the most productive. In all the strains, nitrogen starvation strongly reduced productivity, depressed protein and induced accumulation of carbohydrate (about 50%) in strains F&M-M49 and IAM C-212, and lipid (40 - 45%) in strains PROD1 and CH2. Starved cultures achieved high storage product productivities: 0.12 g L−1 d−1 of lipids for CH2 and 0.19 g L−1 d−1 of carbohydrates for F&M-M49. When extrapolated to large-scale in central Italy, CH2 showed a potential productivity of 41 t ha−1 y−1 for biomass, 16 t ha−1 y−1 for protein and 11 t ha−1 y−1 for lipid under nutrient sufficiency, and 8 t ha−1 y−1 for lipid under nitrogen starvation. Conclusions The environmental and economic sustainability of Chlorella production was enhanced by growing the organisms in a seawater-based medium, so as not to compete with crops for freshwater, and at high temperatures, so as to reduce energy consumption for cooling. All the four

  3. Taxonomic identification and lipid production of two Chilean Chlorella-like strains isolated from a marine and an estuarine coastal environment

    PubMed Central

    González, Mariela A.; Pröschold, Thomas; Palacios, Yussi; Aguayo, Paula; Inostroza, Ingrid; Gómez, Patricia I.

    2013-01-01

    The genus Chlorella was the first microalga to be massively cultured as food, feed and as a source of nutraceuticals. More recently, some species have been suggested as candidates for biodiesel production. One of the most difficult tasks in studying the systematics of green coccoids is the identification of species assigned to the genus Chlorella. In the context of several projects carried out by our research group we isolated two Chlorella-like strains from a marine and an estuarine coastal environment in Chile (Coliumo strain and Baker strain, respectively). The main objectives of this research were to identify these Chilean strains—at the species level—and determine and compare their lipid production when cultured under identical conditions. Cell size and shape, autospore number and sizes, and chloroplast and pyrenoid ultrastructure were considered as taxonomic descriptors, and 18S rDNA sequences and internal transcribed spacer ITS-1 + ITS-2 sequences and secondary structure were adopted as phylogenetic tools. The combined use of these morphological, ultrastructural and molecular attributes revealed that only the Baker strain belongs to the genus Chlorella (C. vulgaris), while the Coliumo strain corresponds to the recently amended genus Chloroidium (C. saccharophilum). Lipid characterization of the biomass obtained from these strains showed that Chlorella vulgaris (Baker strain) appears to be suitable as a raw material for biodiesel production, while Chloroidium saccharophilum (Coliumo strain) would be more appropriate for animal nutrition.

  4. Molecular cloning and expression of hardening-induced genes in Chlorella vulgaris C-27: the most abundant clone encodes a late embryogenesis abundant protein.

    PubMed

    Joh, T; Honjoh, K; Yoshimoto, M; Funabashi, J; Miyamoto, T; Hatano, S

    1995-01-01

    To investigate the effects of hardening on gene expression in Chlorella vulgaris Beijerink IAM C-27 (formerly Chlorella ellipsoidea Gerneck IAM C-27), a frost-hardy strain, 17 cDNA clones corresponding to hardening-induced Chlorella (hiC) genes were isolated by differential screening of a cDNA library from 6-h hardened cells. Northern blot analysis of transcripts of hiC genes showed that these genes are specifically induced by hardening and that their patterns of induction vary. Southern blots of genomic DNAs from two strains (Chlorella ellipsoidea Gerneck IAM C-102, chilling-sensitive; and C. vulgaris C-27, frost-hardy) of Chlorella indicated that ten hiC clones out of 17 hybridized only with DNA of strain C-27 and the other seven clones hybridized with DNA of both strains. However, of these seven clones, transcripts corresponding to six clones did not accumulate in strain C-102 at low temperatures. The sequence of a deduced protein encoded by the most abundant clone, hiC6, exhibited homology to sequences of Group III LEA (late embryogenesis abundant) proteins and had an amino-terminal amino acid sequence that was similar to the sequences of chloroplast transit peptides. PMID:7719632

  5. Effects of brassinazole, an inhibitor of brassinosteroid biosynthesis, on light- and dark-grown Chlorella vulgaris.

    PubMed

    Bajguz, Andrzej; Asami, Tadao

    2004-03-01

    Treatment of cultured Chlorella vulgaris Beijerinck cells with 0.1-10 microM brassinazole (Brz2001), an inhibitor of brassinosteroid (BR) biosynthesis, inhibits their growth during the first 48 h of cultivation in the light. This inhibition is prevented by the co-application of BR. This result suggests that the presence of endogenous BRs during the initial steps of the C. vulgaris cell cycle is indispensable for their normal growth in the light. In darkness, a treatment with 10 nM brassinolide (BL) promotes growth through the first 24 h of culture, but during the following 24 h the cells undergo complete stagnation. Treatment of dark-grown cells with either Brz2001 alone, or a mixture of 10 nM BL and 0.1/10 microM Brz2001, also stimulates their growth. The effects of treatment with 10 nM BL mixed with 0.1-10 microM of a mevalonate-pathway inhibitor (mevinolin), or a non-mevalonate-pathway inhibitor (clomazone), were also investigated. Mevinolin at these concentrations did not inhibit growth of C. vulgaris; however, clomazone did. Addition of BL overcame the inhibition. These results suggest that the mevalonate pathway does not function in C. vulgaris, and that the non-mevalonate pathway for isopentenyl diphosphate biosynthesis is responsible for the synthesis of one of the primary precursors in BR biosynthesis.

  6. Sonication-based isolation and enrichment of Chlorella protothecoides chloroplasts for illumina genome sequencing

    SciTech Connect

    Angelova, Angelina; Park, Sang-Hycuk; Kyndt, John; Fitzsimmons, Kevin; Brown, Judith K

    2013-09-01

    With the increasing world demand for biofuel, a number of oleaginous algal species are being considered as renewable sources of oil. Chlorella protothecoides Krüger synthesizes triacylglycerols (TAGs) as storage compounds that can be converted into renewable fuel utilizing an anabolic pathway that is poorly understood. The paucity of algal chloroplast genome sequences has been an important constraint to chloroplast transformation and for studying gene expression in TAGs pathways. In this study, the intact chloroplasts were released from algal cells using sonication followed by sucrose gradient centrifugation, resulting in a 2.36-fold enrichment of chloroplasts from C. protothecoides, based on qPCR analysis. The C. protothecoides chloroplast genome (cpDNA) was determined using the Illumina HiSeq 2000 sequencing platform and found to be 84,576 Kb in size (8.57 Kb) in size, with a GC content of 30.8 %. This is the first report of an optimized protocol that uses a sonication step, followed by sucrose gradient centrifugation, to release and enrich intact chloroplasts from a microalga (C. prototheocoides) of sufficient quality to permit chloroplast genome sequencing with high coverage, while minimizing nuclear genome contamination. The approach is expected to guide chloroplast isolation from other oleaginous algal species for a variety of uses that benefit from enrichment of chloroplasts, ranging from biochemical analysis to genomics studies.

  7. Combined Extraction Processes of Lipid from Chlorella vulgaris Microalgae: Microwave Prior to Supercritical Carbon Dioxide Extraction

    PubMed Central

    Dejoye, Céline; Vian, Maryline Abert; Lumia, Guy; Bouscarle, Christian; Charton, Frederic; Chemat, Farid

    2011-01-01

    Extraction yields and fatty acid profiles from freeze-dried Chlorella vulgaris by microwave pretreatment followed by supercritical carbon dioxide (MW-SCCO2) extraction were compared with those obtained by supercritical carbon dioxide extraction alone (SCCO2). Work performed with pressure range of 20–28 Mpa and temperature interval of 40–70 °C, gave the highest extraction yield (w/w dry weight) at 28 MPa/40 °C. MW-SCCO2 allowed to obtain the highest extraction yield (4.73%) compared to SCCO2 extraction alone (1.81%). Qualitative and quantitative analyses of microalgae oil showed that palmitic, oleic, linoleic and α-linolenic acid were the most abundant identified fatty acids. Oils obtained by MW-SCCO2 extraction had the highest concentrations of fatty acids compared to SCCO2 extraction without pretreatment. Native form, and microwave pretreated and untreated microalgae were observed by scanning electronic microscopy (SEM). SEM micrographs of pretreated microalgae present tearing wall agglomerates. After SCCO2, microwave pretreated microalgae presented several micro cracks; while native form microalgae wall was slightly damaged. PMID:22272135

  8. Chlorella vulgaris up-modulation of myelossupression induced by lead: the role of stromal cells.

    PubMed

    Queiroz, Mary L S; Torello, Cristiane O; Perhs, Simone M C; Rocha, Michelle C; Bechara, Etelvino J H; Morgano, Marcelo A; Valadares, Marize C; Rodrigues, Ana Paula O; Ramos, Aline Lisie; Soares, Chrislaine O

    2008-09-01

    In this study, Chlorella vulgaris (CV) was examined for its chelating effects on the ability of bone marrow stromal cell layer to display myeloid progenitor cells in vitro in lead-exposed mice, using the long-term bone marrow culture (LTBMC). In addition, the levels of interleukin (IL)-6, an important hematopoietic stimulator, as well as the numbers of adherent and non-adherent cells were also investigated. Mice were gavage treated daily with a single 50mg/kg dose of CV for 10 days, concomitant to continuous offering of 1300ppm lead acetate in drinking water. We found that CV up-modulates the reduced ability of stromal cell layer to display myeloid progenitor cells in vitro in lead-exposed mice and restores both the reduced number of non-adherent cells and the ability of stromal cells from these mice to produce IL-6. Monitoring of lead poisoning demonstrated that CV treatment significantly reduced lead levels in blood and tissues, completely restored the normal hepatic ALA levels, decreased the abnormally high plasma ALA and partly recovered the liver capacity to produce porphyrins. These findings provide evidence for a beneficial use of CV for combination or alternative chelating therapy to protect the host from the damage induced by lead poisoning.

  9. Chlorella vulgaris production enhancement with supplementation of synthetic medium in dairy manure wastewater.

    PubMed

    Shi, Jun; Pandey, Pramod K; Franz, Annaliese K; Deng, Huiping; Jeannotte, Richard

    2016-03-01

    To identify innovative ways for better utilizing flushed dairy manure wastewater, we have assessed the effect of dairy manure and supplementation with synthetic medium on the growth of Chlorella vulgaris. A series of experiments were carried out to study the impacts of pretreatment of dairy wastewater and the benefits of supplementing dairy manure wastewater with synthetic medium on C. vulgaris growth increment and the ultrastructure (chloroplast, starch, lipid, and cell wall) of C. vulgaris cells. Results showed that the biomass production of C. vulgaris in dairy wastewater can be enhanced by pretreatment and using supplementation with synthetic media. A recipe combining pretreated dairy wastewater (40 %) and synthetic medium (60 %) exhibited an improved growth of C. vulgaris. The effects of dairy wastewater on the ultrastructure of C. vulgaris cells were distinct compared to that of cells grown in synthetic medium. The C. vulgaris growth in both synthetic medium and manure wastewater without supplementing synthetic medium was lower than the growth in dairy manure supplemented with synthetic medium. We anticipate that the results of this study will help in deriving an enhanced method of coupling nutrient-rich dairy manure wastewater for biofuel production.

  10. Effects of sodium pentaborate pentahydrate exposure on Chlorella vulgaris growth, chlorophyll content, and enzyme activities.

    PubMed

    Chen, Xueqing; Pei, Yuansheng

    2016-10-01

    Sodium pentaborate pentahydrate (SPP) is a rare mineral. In this study, SPP was synthesized from boric acid and borax through low-temperature crystallization, and its effects on the growth of the alga, Chlorella vulgaris (C. vulgaris) were assessed. The newly synthesized SPP was characterized by chemical analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, and differential thermal analysis. The changes in C. vulgaris growth, chlorophyll content, and enzyme activities upon exposure to SPP for 168h were evaluated. Results showed that SPP treatment was detrimental to C. vulgaris growth during the first 24-120h of exposure. The harmful effects, however, diminished over time (168h), even at an effective medium concentration of 226.37mg BL(-1) (the concentration of boron applied per liter of culture medium). A similar trend was observed for chlorophyll content (chlorophyll a and b) and indicated that the photosynthesis of C. vulgaris was not affected and that high levels of SPP may even promote chlorophyll synthesis. Superoxide dismutase and catalase activities of C. vulgaris increased during 24-120h exposure to SPP, but these activities gradually decreased as culture time progressed. In other words, the initial detrimental effects of synthetic SPP on C. vulgaris were temporary and reversible. This research provides a scientific basis for applications of SPP in the environment. PMID:27367150

  11. Growth of Chlorella vulgaris on sugarcane vinasse: the effect of anaerobic digestion pretreatment.

    PubMed

    Marques, Sheyla Santa Isabel; Nascimento, Iracema Andrade; de Almeida, Paulo Fernando; Chinalia, Fábio Alexandre

    2013-12-01

    Microalgae farming has been identified as the most eco-sustainable solution for producing biodiesel. However, the operation of full-scale plants is still limited by costs and the utilization of industrial and/or domestic wastes can significantly improve economic profits. Several waste effluents are valuable sources of nutrients for the cultivation of microalgae. Ethanol production from sugarcane, for instance, generates significant amounts of organically rich effluent, the vinasse. After anaerobic digestion treatment, nutrient remaining in such an effluent can be used to grow microalgae. This research aimed to testing the potential of the anaerobic treated vinasse as an alternative source of nutrients for culturing microalgae with the goal of supplying the biodiesel industrial chain with algal biomass and oil. The anaerobic process treating vinasse reached a steady state at about 17 batch cycles of 24 h producing about 0.116 m(3)CH4 kgCODvinasse (-1). The highest productivity of Chlorella vulgaris biomass (70 mg l(-1) day(-1)) was observed when using medium prepared with the anaerobic digester effluent. Lipid productivity varied from 0.5 to 17 mg l(-1) day(-1). Thus, the results show that it is possible to integrate the culturing of microalgae with the sugarcane industry by means of anaerobic digestion of the vinasse. There is also the advantageous possibility of using by-products of the anaerobic digestion such as methane and CO2 for sustaining the system with energy and carbon source, respectively. PMID:24013860

  12. Regulation of lipid metabolism in the green microalga Chlorella protothecoides by heterotrophy-photoinduction cultivation regime.

    PubMed

    Li, Yuqin; Xu, Hua; Han, Fangxin; Mu, Jinxiu; Chen, Di; Feng, Bo; Zeng, Hongyan

    2015-09-01

    Proteomics in conjunction with biochemical strategy was employed to unravel regulation of lipid metabolism in the green microalga Chlorella protothecoides by heterotrophy-photoinduction cultivation regime (HPC). Interestingly, HPC triggered transiently synthesis of starch followed by substantial lipid accumulation. And a marked decrease in intracellular protein and chlorophyll contents was also observed after 12h of photo-induction. The highest lipid content of 50.5% was achieved upon the photo-induction stage, which represented 69.3% higher than that of the end of heterotrophic cultivation. Results suggested that turnover of carbon-nitrogen-rich compounds such as starch, protein, and chlorophyll might provide carbon or energy for lipid accumulation. The proteomics analysis indicated that several pathways including glycolysis, TCA cycle, β-oxidation of fatty acids, Calvin cycle, photosynthesis, energy and transport, protein biosynthesis, regulate and defense were involved in the lipid biosynthesis. Malate dehydrogenase and acyl-CoA dehydrogenase were suggested as key regulatory factors in enhancing lipid accumulation. PMID:25127016

  13. Optimization of CO₂ fixation by Chlorella kessleri cultivated in a closed raceway photo-bioreactor.

    PubMed

    Kasiri, Sepideh; Ulrich, Ania; Prasad, Vinay

    2015-10-01

    The aim of this study is to optimize biological fixation of CO2 using Chlorella kessleri cultivated in oil sands process water (OSPW). A lab-scale closed raceway photobioreactor was designed and assembled for cultivation of C. kessleri in OSPW. A fed-batch model describing the dynamics of microalgae growth and CO2, phosphate and ammonium uptake rate was developed based on batch kinetics identified in our previous study, and was successfully validated against experimental data. A model-based optimization method was used to calculate the optimal feeding strategies for CO2, phosphate and light intensity which resulted in a 1.5-fold increase in the final biomass concentration and a 2-fold increase in the average CO2 uptake rate in 240 h (10 days) compared to the initial fed-batch experiment over 432 h (18 days). Finally, scale-up to large-scale continuous operation was considered, and the optimal hydraulic retention time (HRT) and feeding strategy for maximum productivity were estimated. PMID:26188557

  14. Novel bioconversions of municipal effluent and CO₂ into protein riched Chlorella vulgaris biomass.

    PubMed

    Li, Changling; Yang, Hailin; Li, Yuji; Cheng, Luping; Zhang, Meng; Zhang, Ling; Wang, Wu

    2013-03-01

    Batch, modified semi-continuous and continuous cultivations of Chlorella vulgaris C9-JN 2010 cells in municipal effluent were performed and analyzed. The experiments were carried out in 7.5-L photo-bioreactors, to which 2% of CO2 was supplied. Biomass and specific growth rate of C. vulgaris were 0.528-0.760gl(-1) and 0.200-0.374d(-1), respectively. Meanwhile, it could efficiently remove ammonia-N, total nitrogen, total phosphorus, CODCr and BOD5 by around 98.0%, 90.9-93.6%, 89.9-91.8%, 60.7-90.0% and 83.4-88.4%, respectively. Algal protein content was 550±30.0mgg(-1) of the harvested biomass of C. vulgaris which was rich in eight kinds of essential amino acids (around 44.5% of the total). The processes of cultivation of C. vulgaris in municipal effluent could be proposed as dual-beneficial approaches, which could produce profitable byproducts and simultaneously reduce the contaminations to environment. PMID:23399495

  15. Magnesium Uptake by the Green Microalga Chlorella vulgaris in Batch Cultures.

    PubMed

    Ben Amor-Ben Ayed, Hela; Taidi, Behnam; Ayadi, Habib; Pareau, Dominique; Stambouli, Moncef

    2016-03-01

    The accumulation (internal and superficial distribution) of magnesium ions (Mg(2+)) by the green freshwater microalga Chlorella vulgaris (C. vulgaris) was investigated under autotrophic culture in a stirred photobioreactor. The concentrations of the three forms of Mg(2+) (dissolved, extracellular, and intracellular) were determined with atomic absorption spectroscopy during the course of C. vulgaris growth. The proportions of adsorbed (extracellular) and absorbed (intracellular) Mg(2+) were quantified. The concentration of the most important pigment in algal cells, chlorophyll a, increased over time in proportion to the increase in the biomass concentration, indicating a constant chlorophyll/biomass ratio during the linear growth phase. The mean-average rate of Mg(2+) uptake by C. vulgaris grown in a culture medium starting with 16 mg/l of Mg(2+) concentration was measured. A clear relationship between the biomass concentration and the proportion of the Mg(2+) removal from the medium was observed. Of the total Mg(2+) present in the culture medium, 18% was adsorbed on the cell wall and 51% was absorbed by the biomass by the end of the experiment (765 h). Overall, 69% of the initial Mg(2+) were found to be removed from the medium. This study supported the kinetic model based on a reversible first-order reaction for Mg(2+) bioaccumulation in C. vulgaris, which was consistent with the experimental data. PMID:26628253

  16. Inhibition of Alkaline Flocculation by Algal Organic Matter for Chlorella vulgaris

    SciTech Connect

    Vandamme, Dries; Beuckels, Annelies; Vadelius, Eric; Depraetere, Orily; Noppe, Wim; Dutta, Abhishek; Foubert, Imogen; Laurens, Lieve; Muylaert, Koenraad

    2016-01-01

    Alkaline flocculation is a promising strategy for the concentration of microalgae for bulk biomass production. However, previous studies have shown that biological changes during the cultivation negatively affect flocculation efficiency. The influence of changes in cell properties and in the quality and composition of algal organic matter (AOM) were studied using Chlorella vulgaris as a model species. In batch cultivation, flocculation was increasingly inhibited over time and mainly influenced by changes in medium composition, rather than biological changes at the cell surface. Total carbohydrate content of the organic matter fraction sized bigger than 3 kDa increased over time and this fraction was shown to be mainly responsible for the inhibition of alkaline flocculation. The monosaccharide identification of this fraction mainly showed the presence of neutral and anionic monosaccharides. An addition of 30–50 mg L-1 alginic acid, as a model for anionic carbohydrate polymers containing uronic acids, resulted in a complete inhibition of flocculation. Furthermore, these results suggest that inhibition of alkaline flocculation was caused by interaction of anionic polysaccharides leading to an increased flocculant demand over time.

  17. Exploration of upstream and downstream process for microwave assisted sustainable biodiesel production from microalgae Chlorella vulgaris.

    PubMed

    Sharma, Amit Kumar; Sahoo, Pradeepta Kumar; Singhal, Shailey; Joshi, Girdhar

    2016-09-01

    The present study explores the integrated approach for the sustainable production of biodiesel from Chlorella vulgaris microalgae. The microalgae were cultivated in 10m(2) open raceway pond at semi-continuous mode with optimum volumetric and areal production of 28.105kg/L/y and 71.51t/h/y, respectively. Alum was used as flocculent for harvesting the microalgae and optimized at different pH. Lipid was extracted using chloroform: methanol (2:1) and having 12.39% of FFA. Effect of various reaction conditions such as effect of catalyst, methanol:lipid ratio, reaction temperature and time on biodiesel yields were studied under microwave irradiation; and 84.01% of biodiesel yield was obtained under optimized reaction conditions. A comparison was also made between the biodiesel productions under conventional heating and microwave irradiation. The synthesized biodiesel was characterized by (1)H NMR, (13)C NMR, FTIR and GC; however, fuel properties of biodiesel were also studied using specified test methods as per ASTM and EN standards. PMID:27318156

  18. Production of biodiesel from Chlorella sp. enriched with oyster shell extracts.

    PubMed

    Choi, Cheol Soon; Choi, Woon Yong; Kang, Do Hyung; Lee, Hyeon Yong

    2014-01-01

    This study investigated the cultivation of the marine microalga Chlorella sp. without supplying an inorganic carbon source, but instead with enriching the media with extracts of oyster shells pretreated by a high-pressure homogenization process. The pretreated oyster shells were extracted by a weak acid, acetic acid, that typically has harmful effects on cell growth and also poses environmental issues. The concentration of the residual dissolved carbon dioxide in the medium was sufficient to maintain cell growth at 32 ppm and pH 6.5 by only adding 5% (v/v) of oyster shell extracts. Under this condition, the maximum cell density observed was 2.74 g dry wt./L after 27 days of cultivation. The total lipid content was also measured as 18.1 (%, w/w), and this value was lower than the 23.6 (%, w/w) observed under nitrogen deficient conditions or autotrophic conditions. The fatty acid compositions of the lipids were also measured as 10.9% of C16:1 and 16.4% of C18:1 for the major fatty acids, which indicates that the biodiesel from this culture process should be a suitable biofuel. These results suggest that oyster shells, environmental waste from the food industry, can be used as a nutrient and carbon source with seawater, and this reused material should be important for easily scaling up the process for an outdoor culture system.

  19. Cultivation of Chlorella protothecoides in anaerobically treated brewery wastewater for cost-effective biodiesel production.

    PubMed

    Darpito, Cornelius; Shin, Won-Sub; Jeon, Seungjib; Lee, Hansol; Nam, Kibok; Kwon, Jong-Hee; Yang, Ji-Won

    2015-03-01

    The use of wastewater has been investigated to overcome the economic challenge involved with a production of microalgae-based biodiesel. In this study, to achieve economical biodiesel production along with effective wastewater treatment at the same time, anaerobically treated brewery wastewater (ABWW) was utilized as a low-cost nutrient source, in the cultivation of Chlorella protothecoides. About 96 and 90 % of total nitrogen and phosphorus in ABWW were removed, respectively, while C. protothecoides was accumulating 1.88 g L(-1) of biomass. The C. protothecoides grown in ABWW showed increases in cell size and cell aggregation, resulting in a near 80 % enhanced harvesting efficiency within 20 min, as compared with only 4 % in BG-11. In addition, the total fatty acid content of the C. protothecoides grown in ABWW increased by 1.84-fold (35.94 ± 1.54 % of its dry cell weight), relative to that of BG-11. PMID:25270406

  20. Batch anaerobic co-digestion of waste activated sludge and microalgae (Chlorella sorokiniana) at mesophilic temperature.

    PubMed

    Beltrán, Carolina; Jeison, David; Fermoso, Fernando G; Borja, Rafael

    2016-08-23

    The microalgae Chlorella sorokiniana are used as co-substrate for waste activated sludge (WAS) anaerobic digestion. The specific objective of this research was to evaluate the feasibility of improving methane production from anaerobic digestion of WAS in co-digestion with this microalga, based on an optimized mixture percentage. Thus, the anaerobic co-digestion of both substrates aims to overcome the drawbacks of the anaerobic digestion of single WAS, simultaneously improving its management. Different co-digestion mixtures (0% WAS-100% microalgae; 25% WAS-75% microalgae; 50% WAS-50% microalgae; 75% WAS-25% microalgae; 100% WAS-0% microalgae) were studied. The highest methane yield (442 mL CH4/g VS) was obtained for the mixture with 75% WAS and 25% microalgae. This value was 22% and 39% higher than that obtained in the anaerobic digestion of the sole substrates WAS and microalgae, respectively, as well as 16% and 25% higher than those obtained for the co-digestion mixtures with 25% WAS and 75% microalgae and 50% WAS and 50% microalgae, respectively. The kinetic constant of the process increased 42%, 42% and 12%, respectively, for the mixtures with 25%, 50% and 75% of WAS compared to the substrate without WAS. Anaerobic digestion of WAS, together with C. sorokiniana, has been clearly improved by ensuring its viability, suitability and efficiency. PMID:27230742

  1. Extraction of Lipids from Chlorella saccharophila Using High-Pressure Homogenization Followed by Three Phase Partitioning.

    PubMed

    Mulchandani, Ketan; Kar, Jayaranjan R; Singhal, Rekha S

    2015-07-01

    Commercial exploitation of microalgae for biofuel and food ingredients is hindered due to laborious extraction protocols and use of hazardous chemicals. Production of lipids in the microalga grown in modified BG11 medium was evaluated to arrive at the appropriate harvesting conditions. The use of three phase partitioning (TPP) as a green approach for extraction of lipids from Chlorella saccharophila was investigated. Cells disrupted by probe sonication were used for separation of lipids by TPP. The TPP-optimized conditions of 30 % ammonium sulfate, using slurry/t-butanol of 1:0.75 for 60 min at 25 to 35 °C, showed a lipid recovery of 69.05 ± 3.12 % (w/w) as against 100 % (w/w) by using chloroform-methanol extraction. Subsequently, parameters of high-pressure homogenization for cell disruption were optimized for maximum recovery of lipids by TPP. A final recovery of 89.91 ± 3.69 % (w/w) lipids was obtained along with ∼1.26 % w/w carotenoids of dry biomass in the t-butanol layer and protein content of ∼12 % w/w of dry biomass in the middle protein layer due to ammonium sulfate precipitation, after performing TPP under the optimized conditions.

  2. Metal distributions in complexes with Chlorella vulgaris in seawater and wastewater

    SciTech Connect

    Pascucci, P.R.; Kowalak, A.D.

    1999-10-01

    Divalent cadmium (Cd), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) simultaneous complexes with an algal biomass Chlorella vulgaris were studied for bioremediation purposes in various aqueous media: distilled-deionized water (DDIW), seawater, nuclear-reactor pool water, and process wastewater. Reactions were monitored using various dry masses of algae at constant temperature and constant metal concentrations for reaction times ranging from 0 to 150 minutes. Complexes occurred within 30 minutes and reached a steady state after 80 to 120 minutes. Distribution constants (K{prime}{sub d}) were calculated for the complexes and relative orders of K{prime}{sub d} were reported. The K{prime}{sub d} are used to evaluate relative efficiency of metal remediation from waters. Lead, Cu, and Ni complexes had the greatest K{prime}{sub d} values and those metals were most efficiently removed from these waters. Zinc and Fe formed the most labile complexes. The order of K{prime}{sub d} values for complexes in DDIW was Pb > Cu > Cd > Zn, then Cu > Cd > Zn in seawater, Cd > Cu > Zn in reactor pool water, and Ni > Cd > Cu > Zn > Fe in wastewater. C. vulgaris biomass may potentially be used as an alternative to traditional water treatment methods for simultaneous extraction of metals from seawater, process wastewater, or drinking water.

  3. Technique for harvesting unicellular algae using colloidal gas aphrons. [Chlorella vulgaris

    SciTech Connect

    Honeycutt, S.S.; Wallis, D.A.; Sebba, F.

    1983-01-01

    A novel technique using colloidal gas aphron (CGA) dispersions has been investigated for harvesting Chlorella vulgaris, a unicellular green algae, from dilute suspension. CGA are very small gas bubbles, on the order of 25 ..mu..m in diameter, that are each encapsulated in an aqueous shell of surfactant solution. The process is based on the technology of CGA flotation, which involves the formation of algae-bubble complexes and their subsequent flotation to the surface. At neutral pH, the efficiency of algae removal was maximized when a cationic surfactant (lauryl pyridinium chloride) was used for CGA generation. At pH 10, both the cationic and anionic (sodium dodecyl benzene sulfonate) CGA dispersions yielded comparable removals. Addition of small quantities of alum (to 10/sup -4/M) improved removals using the cationic CGA, and at pH 10 this combination yielded the maximum removals that were achieved: 52.1% removal after a single application of CGA dispersion (1 to 1, dispersion to sample volume ratio), and 89.2% removal after an additional application. 12 references, 1 figure, 2 tables.

  4. Isolation and Analysis of the Cppsy Gene and Promoter from Chlorella protothecoides CS-41.

    PubMed

    Li, Meiya; Cui, Yan; Gan, Zhibing; Shi, Chunlei; Shi, Xianming

    2015-10-28

    Phytoene synthase (PSY) catalyzes the condensation of two molecules of geranylgeranyl pyrophosphate to form phytoene, the first colorless carotene in the carotenoid biosynthesis pathway. So it is regarded as the crucial enzyme for carotenoid production, and has unsurprisingly been involved in genetic engineering studies of carotenoid production. In this study, the psy gene from Chlorella protothecoides CS-41, designated Cppsy, was cloned using rapid amplification of cDNA ends. The full-length DNA was 2488 bp, and the corresponding cDNA was 1143 bp, which encoded 380 amino acids. Computational analysis suggested that this protein belongs to the Isoprenoid_Biosyn_C1 superfamily. It contained the consensus sequence, including three predicted substrate-Mg(2+) binding sites. The Cppsy gene promoter was also cloned and characterized. Analysis revealed several candidate motifs for the promoter, which exhibited light- and methyl jasmonate (MeJA)-responsive characteristics, as well as some typical domains universally discovered in promoter sequences, such as the TATA-box and CAAT-box. Light- and MeJA treatment showed that the Cppsy expression level was significantly enhanced by light and MeJA. These results provide a basis for genetically modifying the carotenoid biosynthesis pathway in C. protothecoides.

  5. Cell growth kinetics of Chlorella sorokiniana and nutritional values of its biomass.

    PubMed

    Kumar, Kanhaiya; Dasgupta, Chitralekha Nag; Das, Debabrata

    2014-09-01

    The present study investigates the effects of different physico-chemical parameters for the growth of Chlorella sorokiniana and subsequently determination of nutritional values of its biomass. Most suitable temperature, light intensity, pH, and acetic acid concentration were 30°C, 100 μmol m(-2)s(-1), pH 7.5, and 34.8mM, respectively for the growth of this microorganism. Arrhenius growth activation energy, Ea was calculated as 7.08 kJ mol(-1). Monod kinetics constants: maximum specific growth rate (μ max) and substrate (acetic acid) affinity coefficient (Ks) were determined as 0.1 ± 0.01 h(-1) and 76 ± 8 mg L(-1), respectively. Stoichiometric analysis revealed the capture of 1.83 g CO2 and release of 1.9 g O2 for 1g algal biomass synthesis. Algal biomass of C. sorokiniana was found rich in protein and several important minerals such as Mg, Ca, and Fe. Astaxanthin and β-carotene were extracted and quantified using high performance liquid chromatography.

  6. Crystallization and Crystal-Packing Studies of Chlorella Virus Deoxyuridine Triphosphatase

    SciTech Connect

    Homma, K.; Moriyama, H

    2009-01-01

    The 141-amino-acid deoxyuridine triphosphatase (dUTPase) from the algal Chlorella virus IL-3A and its Glu81Ser/Thr84Arg-mutant derivative Mu-22 were crystallized using the hanging-drop vapor-diffusion method at 298 K with polyethylene glycol as the precipitant. An apo IL-3A dUTPase with an amino-terminal T7 epitope tag and a carboxy-terminal histidine tag yielded cubic P2{sub 1}3 crystals with unit-cell parameter a = 106.65 {angstrom}. In the presence of dUDP, the enzyme produced thin stacked orthorhombic P222 crystals with unit-cell parameters a = 81.0, b = 96.2, c = 132.8 {angstrom}. T7-histidine-tagged Mu-22 dUTPase formed thin stacked rectangular crystals. Amino-terminal histidine-tagged dUTPases did not crystallize but formed aggregates. Glycyl-seryl-tagged dUTPases yielded cubic P2{sub 1}3 IL-3A crystals with unit-cell parameter a = 105.68 {angstrom} and hexagonal P6{sub 3} Mu-22 crystals with unit-cell parameters a = 132.07, c = 53.45 {angstrom}, {gamma} = 120{sup o}. Owing to the Thr84Arg mutation, Mu-22 dUTPase had different monomer-to-monomer interactions to those of IL-3A dUTPase.

  7. Characterization of activated carbon prepared from chlorella-based algal residue.

    PubMed

    Chang, Yuan-Ming; Tsai, Wen-Tien; Li, Ming-Hsuan

    2015-05-01

    The chlorella-based microalgal residue (AR) was tested as a novel precursor for preparing activated carbons. A combined carbonization-activation process with flowing N2 and CO2 gases was used to prepare the carbon materials at the activation temperatures of 800-1000 °C and the residence times of 0-30 min in this work. The elemental contents, pore properties and scanning electron microscopy (SEM) observations of the resulting activated carbons have been performed. The results showed that activation temperature may be the most important parameter for determining their pore properties. The maximal Brunauer-Emmett-Teller (BET) surface area and total pore volume of the resulting activated carbon, which was produced at the activation temperature of 950 °C with the residence time of 30 min, were 840 m(2)/g and 0.46 cm(3)/g, respectively. More interestingly, the resulting activated carbons have significant nitrogen contents of 3.6-9.6 wt%, which make them lower carbon contents (i.e., 54.6-68.4 wt%) than those of commercial activated carbons.

  8. Urban nutrient recovery from fresh human urine through cultivation of Chlorella sorokiniana.

    PubMed

    Zhang, Shanshan; Lim, Chun Yong; Chen, Chia-Lung; Liu, He; Wang, Jing-Yuan

    2014-12-01

    High rate food consumption in urban cities causes vast amounts of nitrogen and phosphorus used in agriculture to end up in urban wastewaters. To substantially recover these nutrients, source-separated human urine should be targeted. The present study was to investigate the feasibility of recovering nitrogen and phosphorus in urine via microalgae cultivation. In concentrated urine, urea hydrolysis and precipitation occur rapidly, making microalgal growth difficult and nutrient recovery ineffective. However, when fresh urine was added as nutrient stock for 1-day growth requirement, biomass of Chlorella sorokiniana grew from 0.44 to 0.96 g L(-1) utilising 62.64 mg L(-1) of N and 10.64 mg L(-1) of P, achieving 80.4% and 96.6% recoveries, respectively in a 1-day non-sterile cultivation cycle. Overall, microalgae grown with urine added as nutrient supplement show no signs of inferiority as compared to those grown in recipe medium BG11 in terms of mass and chlorophyll a growth rates as well as resulting lipids (36.8%) and energy contents (21.0 kJ g(-1)).

  9. Regulation of lipid metabolism in the green microalga Chlorella protothecoides by heterotrophy-photoinduction cultivation regime.

    PubMed

    Li, Yuqin; Xu, Hua; Han, Fangxin; Mu, Jinxiu; Chen, Di; Feng, Bo; Zeng, Hongyan

    2015-09-01

    Proteomics in conjunction with biochemical strategy was employed to unravel regulation of lipid metabolism in the green microalga Chlorella protothecoides by heterotrophy-photoinduction cultivation regime (HPC). Interestingly, HPC triggered transiently synthesis of starch followed by substantial lipid accumulation. And a marked decrease in intracellular protein and chlorophyll contents was also observed after 12h of photo-induction. The highest lipid content of 50.5% was achieved upon the photo-induction stage, which represented 69.3% higher than that of the end of heterotrophic cultivation. Results suggested that turnover of carbon-nitrogen-rich compounds such as starch, protein, and chlorophyll might provide carbon or energy for lipid accumulation. The proteomics analysis indicated that several pathways including glycolysis, TCA cycle, β-oxidation of fatty acids, Calvin cycle, photosynthesis, energy and transport, protein biosynthesis, regulate and defense were involved in the lipid biosynthesis. Malate dehydrogenase and acyl-CoA dehydrogenase were suggested as key regulatory factors in enhancing lipid accumulation.

  10. Characterization of lipid and fatty acids composition of Chlorella zofingiensis in response to nitrogen starvation.

    PubMed

    Zhu, Shunni; Wang, Yajie; Shang, Changhua; Wang, Zhongming; Xu, Jingliang; Yuan, Zhenhong

    2015-08-01

    Cellular biochemical composition of the microalga Chlorella zofingiensis was studied under favorable and nitrogen starvation conditions, with special emphasis on lipid classes and fatty acids distribution. When algal cells were grown in nitrogen-free medium (N stress), the increase in the contents of lipid and carbohydrate while a decrease in protein content was detected. Glycolipids were the major lipid fraction (50.7% of total lipids) under control condition, while neutral lipids increased to be predominant (86.7% of total lipids) under N stress condition. Triacylglycerol (TAG) content in N stressed cells was 27.3% dw, which was over three times higher than that obtained under control condition. Within neutral lipids fraction, monounsaturated fatty acids (MUFA) were the main group (40.6%) upon N stress, in which oleic acid was the most representative fatty acids (34.5%). Contrarily, glycolipids and phospholipids showed a higher percentage of polyunsaturated fatty acids (PUFA). Lipid quality assessment indicated the potential of this alga as a biodiesel feedstock when its neutral lipids were a principal lipid fraction. The results demonstrate that the neutral lipids content is key to determine the suitability of the microalga for biodiesel, and the stress cultivation is essential for lipid quality.

  11. Kinetic Model of Photoautotrophic Growth of Chlorella sp. Microalga, Isolated from the Setúbal Lagoon.

    PubMed

    Heinrich, Josué Miguel; Irazoqui, Horacio Antonio

    2015-01-01

    In this work, a kinetic expression relating light availability in the culture medium with the rate of microalgal growth is obtained. This expression, which is valid for low illumination conditions, was derived from the reactions that take part in the light-dependent stage of photosynthesis. The kinetic expression obtained is a function of the biomass concentration in the culture, as well as of the local volumetric rate of absorption of photons, and only includes two adjustable parameters. To determine the value of these parameters and to test the validity of the hypotheses made, autotrophic cultures of the Chlorella sp. strain were carried out in a modified BBM medium at three CO2 concentrations in the gas stream, namely 0.034%, 0.34% and 3.4%. Moreover, the local volumetric rate of photon absorption was predicted based on a physical model of the interaction of the radiant energy with the suspended biomass, together with a Monte Carlo simulation algorithm. The proposed intrinsic expression of the biomass growth rate, together with the Monte Carlo radiation field simulator, are key to scale up photobioreactors when operating under low irradiation conditions, independently of the configuration of the reactor and of its light source.

  12. [Growth inhibition and mechanism of cetyltrimethyl ammonium chloride on Chlorella vulgaris].

    PubMed

    Xu, Yin; Ge, Fei; Tao, Neng-Guo; Zhu, Run-Liang; Wang, Na

    2009-06-15

    Growth inhibition of cetyltrimethyl ammonium chloride (CTAC), a cationic surfactants, on Chlorella vulgaris was investigated at batch culture in laboratory. Furthermore, the corresponding mechanisms were studied by the determination of absorption capacity, Zeta potential, activity of acid phosphatase and ultrastructure of algae. Results show that the growth inhibition by CATC is enhanced with its concentration increasing from 0.1 mg/L to 1 mg/L, and 96 h-EC50 of CTAC is 0.18 mg/L. In the presence of 0.3 mg/L CTAC in 8 d, the inhibition efficiency of biomass reaches 70.7%. Meanwhile, the absorption of nitrogen and iron is inhibited 83.9% and 86.2% respectively with Zeta potential of algae cell increasing from -12.5 mV to -6.7 mV. Furthermore, the relative activity of acid phosphatase declines to 23.1% at the same time. Plasmolysis, distortion of pyrenoid and swelling of lysosome is observed in the cell. Above phenomena indicates that CTAC increases the Zeta potential of algae cell and thus inhibites the absorption of nitrogen and iron. In addition, CTAC may affect the metabolism of phosphorus and change the ultrastructure of algae cell. PMID:19662866

  13. Construction and operation of microbial fuel cell with Chlorella vulgaris biocathode for electricity generation.

    PubMed

    Wu, Xia-yuan; Song, Tian-shun; Zhu, Xu-jun; Wei, Ping; Zhou, Charles C

    2013-12-01

    In this study, a modified microbial fuel cell (MFC) with a tubular photobioreactor (PHB) configuration as a cathode compartment was constructed by introducing Chlorella vulgaris to the cathode chamber used to generate oxygen in situ. Two types of cathode materials and light/dark cycles were used to test the effect on MFC with algae biocathode. Results showed that the use of algae is an effective approach because these organisms can act as efficient in situ oxygenators, thereby facilitating the cathodic reaction. Dissolved oxygen and voltage output displayed a clear light positive response and were drastically enhanced compared with the abiotic cathode. In particular, carbon paper-coated Pt used as a cathode electrode increased voltage output at a higher extent than carbon felt used as an electrode. The maximum power density of 24.4 mW/m(2) was obtained from the MFC with algae biocathode which utilized the carbon paper-coated Pt as the cathode electrode under intermittent illumination. This density was 2.8 times higher than that of the abiotic cathode. Continuous illumination shortened the algal lifetime. These results demonstrated that intermittent illumination and cathode material-coated catalyst are beneficial to a more efficient and prolonged operation of MFC with C. vulgaris biocathode.

  14. Construction and operation of microbial fuel cell with Chlorella vulgaris biocathode for electricity generation.

    PubMed

    Wu, Xia-yuan; Song, Tian-shun; Zhu, Xu-jun; Wei, Ping; Zhou, Charles C

    2013-12-01

    In this study, a modified microbial fuel cell (MFC) with a tubular photobioreactor (PHB) configuration as a cathode compartment was constructed by introducing Chlorella vulgaris to the cathode chamber used to generate oxygen in situ. Two types of cathode materials and light/dark cycles were used to test the effect on MFC with algae biocathode. Results showed that the use of algae is an effective approach because these organisms can act as efficient in situ oxygenators, thereby facilitating the cathodic reaction. Dissolved oxygen and voltage output displayed a clear light positive response and were drastically enhanced compared with the abiotic cathode. In particular, carbon paper-coated Pt used as a cathode electrode increased voltage output at a higher extent than carbon felt used as an electrode. The maximum power density of 24.4 mW/m2 was obtained from the MFC with algae biocathode which utilized the carbon paper-coated Pt as the cathode electrode under intermittent illumination. This density was 2.8 times higher than that of the abiotic cathode. Continuous illumination shortened the algal lifetime. These results demonstrated that intermittent illumination and cathode material-coated catalyst are beneficial to a more efficient and prolonged operation of MFC with C. vulgaris biocathode.

  15. Production, extraction and stabilization of lutein from microalga Chlorella sorokiniana MB-1.

    PubMed

    Chen, Chun-Yen; Jesisca; Hsieh, Chienyan; Lee, Duu-Jong; Chang, Chien-Hsiang; Chang, Jo-Shu

    2016-01-01

    The efficiencies of extraction and preservation of lutein from microalgae are critical for the success of its commercialization. In this study, lutein was produced by Chlorella sorokiniana MB-1 via semi-batch mixotrophic cultivation. The microalgal biomass with a lutein content of 5.21mg/g was pretreated by bead-beating and high pressure cell disruption methods, and the lutein content was harvested by a reduced pressure extraction method. The effect of pretreatment, pressure, solvent type, extraction time and temperature on lutein recovery was investigated. Using high pressure pretreatment followed by extraction with tetrahydrofuran (THF) as solvent resulted in high lutein recovery efficiencies of 87.0% (20min) and 99.5% (40min) at 850mbar and 25°C. In contrast, using ethanol as the solvent, 86.2% lutein recovery was achieved under 450mbar, 35°C and 40min extraction. The extracted lutein was stabilized in olive oil or sunflower oil with half-lives of 53.1 and 63.8days, respectively.

  16. Effect of Chlorella sorokiniana on the biological denitrification of drinking water.

    PubMed

    Petrovič, Aleksandra; Simonič, Marjana

    2015-04-01

    The influence of Chlorella sorokiniana on drinking water's biological denitrification was studied at two different initial nitrate concentrations, 50 and 100 mg/L, respectively. Sucrose and grape juice were used as carbon sources. The experiments showed that the denitrification process in the presence of algae was, even at low concentrations, i.e. 50 mg/L of nitrate, slower than without them, but yet still more than 95% of nitrate was removed in 24 h. It was also discovered that, with the addition of ammonium and urea, the urea interfered much more with the denitrification process, as less than 50% of the initial nitrate was removed. However, algae did not contribute to the nitrate and ammonium removals, as the final concentrations of both in the presence of algae were higher by approx 5%. At 100 mg/L of initial nitrate, the denitrification kinetics in the presence of algae was apparently slower regarding those experiments at lower levels of nitrate and only 65-70% of nitrate was removed over 24 h. Using grape juice instead of sucrose improved the nitrate removal slightly.

  17. Identification of Distinct Internal and External Isozymes of Carbonic Anhydrase in Chlorella saccharophila.

    PubMed Central

    Williams, T. G.; Colman, B.

    1993-01-01

    External carbonic anhydrase (CA) was detected in whole cells of alkaline-grown Chlorella saccharophila but was suppressed by growth at acid pH or growth on elevated levels of CO2. Internal CA activity was measured potentiometrically as an increase in activity in cell extracts over that of intact cells. Cells grown under all conditions had equal levels of internal CA activity. Two isozymes were identified after electrophoretic separation of soluble proteins on cellulose acetate plates. The fast isozyme was found in cells grown under all conditions, whereas the slow isozyme was found only in cells grown at alkaline pH. Western blot analysis following sodium dodecyl sulfate-polyacrylamide gel electrophoresis using antibodies produced against the periplasmic form of CA from Chlamydomonas reinhardtii revealed a single band at 39 kD, which did not change in intensity between growth conditions and was associated only with proteins eluted from the fast band. The slow isozyme was inactivated by incubation of cell extract at 30[deg]C and by incubation in 10 mM dithiothreitol, whereas the internal form was unaffected. These results indicate that external and internal forms of CA differ in structure and their activities respond differently to environmental conditions. PMID:12231991

  18. A kinetic study of pyrolysis and combustion of microalgae Chlorella vulgaris using thermo-gravimetric analysis.

    PubMed

    Agrawal, Ankit; Chakraborty, Saikat

    2013-01-01

    This work uses thermo-gravimetric, differential thermo-gravimetric and differential thermal analyses to evaluate the kinetics of pyrolysis (in inert/N(2) atmosphere) and (oxidative) combustion of microalgae Chlorella vulgaris by heating from 50 to 800 °C at heating rates of 5-40 °C/min. This study shows that combustion produces higher biomass conversion than pyrolysis, and that three stages of decomposition occur in both cases, of which, the second one--consisting of two temperature zones--is the main stage of devolatization. Proteins and carbohydrates are decomposed in the first of the two zones at activation energies of 51 and 45 kJ/mol for pyrolysis and combustion, respectively, while lipids are decomposed in its second zone at higher activation energies of 64 and 63 kJ/mol, respectively. The kinetic expressions of the reaction rates in the two zones for pyrolysis and combustion have been obtained and it has been shown that increased heating rates result in faster and higher conversion.

  19. Simultaneous nutrient removal and lipid production from pretreated piggery wastewater by Chlorella vulgaris YSW-04.

    PubMed

    Ji, Min-Kyu; Kim, Hyun-Chul; Sapireddy, Veer Raghavulu; Yun, Hyun-Shik; Abou-Shanab, Reda A I; Choi, Jaeyoung; Lee, Wontae; Timmes, Thomas C; Inamuddin; Jeon, Byong-Hun

    2013-03-01

    The feasibility of using a microalga Chlorella vulgaris YSW-04 was investigated for removal of nutrients from piggery wastewater effluent. The consequent lipid production by the microalga was also identified and quantitatively determined. The wastewater effluent was diluted to different concentrations ranging from 20 to 80 % of the original using either synthetic media or distilled water. The dilution effect on both lipid production and nutrient removal was evaluated, and growth rate of C. vulgaris was also monitored. Dilution of the wastewater effluent improved microalgal growth, lipid productivity, and nutrient removal. The growth rate of C. vulgaris was increased with decreased concentration of piggery wastewater in the culture media regardless of the diluent type. Lipid production was relatively higher when using synthetic media than using distilled water for dilution of wastewater. The composition of fatty acids accumulated in microalgal biomass was dependent upon both dilution ratio and diluent type. The microalga grown on a 20 % concentration of wastewater effluent diluted with distilled water was more promising for generating high-efficient biodiesel compared to the other culture conditions. The highest removal of inorganic nutrients was also achieved at the same dilution condition. Our results revealed the optimal pretreatment condition for the biodegradation of piggery wastewater with microalgae for subsequent production of high-efficient biodiesel. PMID:22569638

  20. The Bioconcentration and Degradation of Nonylphenol and Nonylphenol Polyethoxylates by Chlorella vulgaris

    PubMed Central

    Sun, Hong-Wen; Hu, Hong-Wei; Wang, Lei; Yang, Ying; Huang, Guo-Lan

    2014-01-01

    Nonylphenol polyethoxylates (NPnEOs), a major class of nonionic surfactants, can easily enter into aquatic environments through various pathways due to their wide applications, which leads to the extensive existence of their relative stable metabolites, namely nonylphenol (NP) and mono- to tri-ethoxylates. This study investigated the bioconcentration and degradation of NP and NPnEO oligomers (n = 1–12) by a green algae, Chlorella vulgaris. Experimental results showed that C. vulgaris can remove NP from water phase efficiently, and bioconcentration and degradation accounted for approximately half of its loss, respectively, with a 48 h BCF (bioconcentration factor) of 2.42 × 103. Moreover, C. vulgaris could concentrate and degrade NPnEOs, distribution profiles of the series homologues of the NPnEOs in algae and water phase were quite different from the initial homologue profile. The 48 h BCF of the NPnEO homologues increased with the length of the EO chain. Degradation extent of total NPnEOs by C. vulgaris was 95.7%, and only 1.1% remained in water phase, and the other 3.2% remained in the algal cells. The algae removed the NPnEOs mainly through degradation. Due to rapid degradation, concentrations of the long chain NPnEO homologous in both water (n ≥ 2) and the algal phase (n ≥ 5) was quite low at the end of a 48 h experiment. PMID:24445260

  1. Mechanistically harvesting of Chlorella vulgaris and Rhodotorula glutinis via modified montmorillonoid.

    PubMed

    Liu, Jing; Zhang, Xu; Tan, Tianwei

    2016-10-01

    In this study, the flocculation process of Chlorella vulgaris and Rhodotorula glutinis induced by inorganic salts modified montmorillonoid was conducted. The maximum flocculation efficiency (FE) of 98.50% for C. vulgaris and 11.83% for R. glutinis were obtained with 4g/L and 5g/L flocculant within the dosage scope of 1-5g/L. The difference of FE was then thermodynamically explained by the extended DLVO theory and the FE of R. glutinis was mechanically enhanced to 90.66% with 0.06g/L cationic polyacrylamide (CPAM) at an optimum pH of 9. After that, aimed to utilize the remainder flocculant capacity, C. vulgaris culture was added to the aggregation of R. glutinis. Fortunately, the coagulation of R. glutinis and C. Vulgaris was achieved with 0.05g/L CPAM and 5g/L flocculant at pH 9 and the FE reached 90.15% and 91.24%, respectively. PMID:27420162

  2. Toxicity of Superparamagnetic Iron Oxide Nanoparticles on Green Alga Chlorella vulgaris

    PubMed Central

    Barhoumi, Lotfi

    2013-01-01

    Toxicity of superparamagnetic iron oxide nanoparticles (SPION) was investigated on Chlorella vulgaris cells exposed during 72 hours to Fe3O4 (SPION-1), Co0.2Zn0.8Fe2O4 (SPION-2), or Co0.5Zn0.5Fe2O4 (SPION-3) to a range of concentrations from 12.5 to 400 μg mL−1. Under these treatments, toxicity impact was indicated by the deterioration of photochemical activities of photosynthesis, the induction of oxidative stress, and the inhibition of cell division rate. In comparison to SPION-2 and -3, exposure to SPION-1 caused the highest toxic effects on cellular division due to a stronger production of reactive oxygen species and deterioration of photochemical activity of Photosystem II. This study showed the potential source of toxicity for three SPION suspensions, having different chemical compositions, estimated by the change of different biomarkers. In this toxicological investigation, algal model C. vulgaris demonstrated to be a valuable bioindicator of SPION toxicity. PMID:24369015

  3. Diuron sorbed to carbon nanotubes exhibits enhanced toxicity to Chlorella vulgaris.

    PubMed

    Schwab, Fabienne; Bucheli, Thomas D; Camenzuli, Louise; Magrez, Arnaud; Knauer, Katja; Sigg, Laura; Nowack, Bernd

    2013-07-01

    Carbon nanotubes (CNT) are more and more likely to be present in the environment, where they will associate with organic micropollutants due to strong sorption. The toxic effects of these CNT-micropollutant mixtures on aquatic organisms are poorly characterized. Here, we systematically quantified the effects of the herbicide diuron on the photosynthetic activity of the green alga Chlorella vulgaris in presence of different multiwalled CNT (industrial, purified, pristine, and oxidized) or soot. The presence of carbonaceous nanoparticles reduced the adverse effect of diuron maximally by <78% (industrial CNT) and <34% (soot) at 10.0 mg CNT/L, 5.0 mg soot/L, and diuron concentrations in the range 0.73-2990 μg/L. However, taking into account the measured dissolved instead of the nominal diuron concentration, the toxic effect of diuron was equal to or stronger in the presence of CNT by a factor of up to 5. Sorbed diuron consequently remained partially bioavailable. The most pronounced increase in toxicity occurred after a 24 h exposure of algae and CNT. All results point to locally elevated exposure concentration (LEEC) in the proximity of algal cells associated with CNT as the cause for the increase in diuron toxicity. PMID:23244294

  4. Magnesium aminoclay enhances lipid production of mixotrophic Chlorella sp. KR-1 while reducing bacterial populations.

    PubMed

    Kim, Bohwa; Praveenkumar, Ramasamy; Lee, Jiye; Nam, Bora; Kim, Dong-Myung; Lee, Kyubock; Lee, Young-Chul; Oh, You-Kwan

    2016-11-01

    Improving lipid productivity and preventing overgrowth of contaminating bacteria are critical issues relevant to the commercialization of the mixotrophic microalgae cultivation process. In this paper, we report the use of magnesium aminoclay (MgAC) nanoparticles for enhanced lipid production from oleaginous Chlorella sp. KR-1 with simultaneous control of KR-1-associated bacterial growth in mixotrophic cultures with glucose as the model substrate. Addition of 0.01-0.1g/L MgAC promoted microalgal biomass production better than the MgAC-less control, via differential biocidal effects on microalgal and bacterial cells (the latter being more sensitive to MgAC's bio-toxicity than the former). The inhibition effect of MgAC on co-existing bacteria was, as based on density-gradient-gel-electrophoresis (DGGE) analysis, largely dosage-dependent and species-specific. MgAC also, by inducing an oxidative stress environment, increased both the cell size and lipid content of KR-1, resulting in a considerable, ∼25% improvement of mixotrophic algal lipid productivity (to ∼410mgFAME/L/d) compared with the untreated control. PMID:27543952

  5. Harvesting Chlorella vulgaris by natural increase in pH: effect of medium composition.

    PubMed

    Nguyen, Thi Dong Phuong; Frappart, Matthieu; Jaouen, Pascal; Pruvost, Jérémy; Bourseau, Patrick

    2014-01-01

    The freshwater microalga Chlorella vulgaris was harvested by autoflocculation resulting from the precipitation of magnesium or calcium compounds induced by a slow increase in pH in the absence of CO2 input. Autoflocculation was tested in two culture media with, respectively, ammonium (NH4+) and nitrate (NO3-) ions as nitrogen source. The culture pH increased because of photosynthesis and CO2 stripping. pH rose to 11 after 8 h in the NO3- medium, but did not exceed 9 in the NH4+ medium. No flocculation took place in any of the media. Autoflocculation tests were repeated in the NO(3-)-based culture medium by progressively increasing the concentrations of Ca2+ and Mg2+ until inorganic compounds precipitated and flocculated microalgae. The minimal concentrations for flocculation were found to be 120 mg Ca2 L(-1) and 1000 mg Mg2+ L(-1). These values were, respectively, 3.5 times and 20 times higher than those allowing flocculation by NaOH addition. Energy-dispersive X-ray spectroscopy, zeta potential measurement, and ionic chromatography suggest that the mechanisms involved are different. The rate of cell removal was close to 90% in both cases, but cells were more concentrated in the aggregates obtained by magnesium compound precipitation, with an estimated concentration close to 33 g (dry matter) L(-1), against 19 g L(-1) for calcium phosphates.

  6. Recycling harvest water to cultivate Chlorella zofingiensis under nutrient limitation for biodiesel production.

    PubMed

    Zhu, L D; Takala, J; Hiltunen, E; Wang, Z M

    2013-09-01

    Harvest water recycling for Chlorella zofingiensis re-cultivation under nutrient limitation was investigated. Using 100% harvest water, four cultures were prepared: Full medium, P-limited medium, N-limited medium and N- and P-limited medium, while another full medium was also prepared using 50% harvest water. The results showed that the specific growth rate and biomass productivity ranged from 0.289 to 0.403 day(-1) and 86.30 to 266.66 mg L(-1) day(-1), respectively. Nutrient-limited cultures witnessed much higher lipid content (41.21-46.21% of dry weight) than nutrient-full cultures (26% of dry weight). The N- and P-limited medium observed the highest FAME yield at 10.95% of dry weight, while the N-limited culture and P-limited culture shared the highest biodiesel productivity at 20.66 and 19.91 mg L(-1) day(-1), respectively. The experiment on harvest water recycling times demonstrated that 100% of the harvest water could be recycled twice with the addition of sufficient nutrients.

  7. Polishing of POME by Chlorella sp. in suspended and immobilized system

    NASA Astrophysics Data System (ADS)

    Lahin, F. A.; Sarbatly, R.; Suali, E.

    2016-06-01

    The effect of using suspended and immobilized growth of Chlorella sp. to treat POME was studied. Cotton and nylon ropes were used as the immobilization material in a rotating microalgae biofilm reactor. The result showed that POME treated in suspended growth system was able to remove 81.9% and 55.5% of the total nitrogen (TN) and total phosphorus (TP) respectively. Whereas the immobilized system showed lower removal of 77.22% and 53.02% for TN and TP. Lower performance of immobilized microalgae is due to the limited light penetration and supply of CO2 inside the immobilization materials. The rotating microalgae biofilm reactor was able to reduce the biochemical oxygen demand (BOD) to 90 mg/L and chemical oxygen demand (COD) to 720 mg/L. Higher BOD and COD reading were obtained in suspended growth due to the presence of small number of microalgae cell in the samples. This study shows that suspended growth system is able to remove higher percentages of nitrogen and phosphorus. However, an efficient separation method such as membrane filtration is required to harvest the cultivated microalgae cell to avoid organic matter release into water bodies.

  8. Isolation and Analysis of the Cppsy Gene and Promoter from Chlorella protothecoides CS-41

    PubMed Central

    Li, Meiya; Cui, Yan; Gan, Zhibing; Shi, Chunlei; Shi, Xianming

    2015-01-01

    Phytoene synthase (PSY) catalyzes the condensation of two molecules of geranylgeranyl pyrophosphate to form phytoene, the first colorless carotene in the carotenoid biosynthesis pathway. So it is regarded as the crucial enzyme for carotenoid production, and has unsurprisingly been involved in genetic engineering studies of carotenoid production. In this study, the psy gene from Chlorella protothecoides CS-41, designated Cppsy, was cloned using rapid amplification of cDNA ends. The full-length DNA was 2488 bp, and the corresponding cDNA was 1143 bp, which encoded 380 amino acids. Computational analysis suggested that this protein belongs to the Isoprenoid_Biosyn_C1 superfamily. It contained the consensus sequence, including three predicted substrate-Mg2+ binding sites. The Cppsy gene promoter was also cloned and characterized. Analysis revealed several candidate motifs for the promoter, which exhibited light- and methyl jasmonate (MeJA)-responsive characteristics, as well as some typical domains universally discovered in promoter sequences, such as the TATA-box and CAAT-box. Light- and MeJA treatment showed that the Cppsy expression level was significantly enhanced by light and MeJA. These results provide a basis for genetically modifying the carotenoid biosynthesis pathway in C. protothecoides. PMID:26516871

  9. Virus-host interactions: insights from the replication cycle of the large Paramecium bursaria chlorella virus.

    PubMed

    Milrot, Elad; Mutsafi, Yael; Fridmann-Sirkis, Yael; Shimoni, Eyal; Rechav, Katya; Gurnon, James R; Van Etten, James L; Minsky, Abraham

    2016-01-01

    The increasing interest in cytoplasmic factories generated by eukaryotic-infecting viruses stems from the realization that these highly ordered assemblies may contribute fundamental novel insights to the functional significance of order in cellular biology. Here, we report the formation process and structural features of the cytoplasmic factories of the large dsDNA virus Paramecium bursaria chlorella virus 1 (PBCV-1). By combining diverse imaging techniques, including scanning transmission electron microscopy tomography and focused ion beam technologies, we show that the architecture and mode of formation of PBCV-1 factories are significantly different from those generated by their evolutionary relatives Vaccinia and Mimivirus. Specifically, PBCV-1 factories consist of a network of single membrane bilayers acting as capsid templates in the central region, and viral genomes spread throughout the host cytoplasm but excluded from the membrane-containing sites. In sharp contrast, factories generated by Mimivirus have viral genomes in their core, with membrane biogenesis region located at their periphery. Yet, all viral factories appear to share structural features that are essential for their function. In addition, our studies support the notion that PBCV-1 infection, which was recently reported to result in significant pathological outcomes in humans and mice, proceeds through a bacteriophage-like infection pathway. PMID:26248343

  10. Cultivating Chlorella vulgaris and Scenedesmus quadricauda microalgae to degrade inorganic compounds and pesticides in water.

    PubMed

    Baglieri, Andrea; Sidella, Sarah; Barone, Valeria; Fragalà, Ferdinando; Silkina, Alla; Nègre, Michèle; Gennari, Mara

    2016-09-01

    This work evaluates the possibility of cultivating Scenedesmus quadricauda and Chlorella vulgaris microalgae in wastewater from the hydroponic cultivation of tomatoes with the aim of purifying the water. S. quadricauda and C. vulgaris were also used in purification tests carried out on water contaminated by the following active ingredients: metalaxyl, pyrimethanil, fenhexamid, iprodione, and triclopyr. Fifty-six days after the inoculum was placed, a reduction was found in the concentration of nitric nitrogen, ammonia nitrogen, and soluble and total phosphorus. The decrease was 99, 83, 94, and 94 %, respectively, for C. vulgaris and 99, 5, 88, and 89 %, respectively, for S. quadricauda. When the microalgae were present, all the agrochemicals tested were removed more quickly from the water than from the sterile control (BG11). The increase in the rate of degradation was in the order metalaxyl > fenhexamid > iprodione > triclopyr > pyrimethanil. It was demonstrated that there was a real degradation of fenhexamid, metalaxyl, triclopyr, and iprodione, while in the case of pyrimethanil, the active ingredient removed from the substrate was absorbed onto the cells of the microalgae. It was also found that the agrochemicals used in the tests had no significant effect on the growth of the two microalgae. The experiment highlighted the possibility of using cultivations of C. vulgaris and S. quadricauda as purification systems for agricultural wastewater which contains eutrophic inorganic compounds such as nitrates and phosphates and also different types of pesticides. PMID:27259964

  11. Subcritical Water Technology for Enhanced Extraction of Biochemical Compounds from Chlorella vulgaris.

    PubMed

    Awaluddin, S A; Thiruvenkadam, Selvakumar; Izhar, Shamsul; Hiroyuki, Yoshida; Danquah, Michael K; Harun, Razif

    2016-01-01

    Subcritical water extraction (SWE) technology has been used for the extraction of active compounds from different biomass materials with low process cost, mild operating conditions, short process times, and environmental sustainability. With the limited application of the technology to microalgal biomass, this work investigates parametrically the potential of subcritical water for high-yield extraction of biochemicals such as carbohydrates and proteins from microalgal biomass. The SWE process was optimized using central composite design (CCD) under varying process conditions of temperature (180-374°C), extraction time (1-20 min), biomass particulate size (38-250 μm), and microalgal biomass loading (5-40 wt.%). Chlorella vulgaris used in this study shows high volatile matter (83.5 wt.%) and carbon content (47.11 wt.%), giving advantage as a feedstock for biofuel production. The results showed maximum total carbohydrate content and protein yields of 14.2 g/100 g and 31.2 g/100 g, respectively, achieved under the process conditions of 277°C, 5% of microalgal biomass loading, and 5 min extraction time. Statistical analysis revealed that, of all the parameters investigated, temperature is the most critical during SWE of microalgal biomass for protein and carbohydrate production. PMID:27366748

  12. Inhibition of alkaline flocculation by algal organic matter for Chlorella vulgaris.

    PubMed

    Vandamme, Dries; Beuckels, Annelies; Vadelius, Eric; Depraetere, Orily; Noppe, Wim; Dutta, Abhishek; Foubert, Imogen; Laurens, Lieve; Muylaert, Koenraad

    2016-01-01

    Alkaline flocculation is a promising strategy for the concentration of microalgae for bulk biomass production. However, previous studies have shown that biological changes during the cultivation negatively affect flocculation efficiency. The influence of changes in cell properties and in the quality and composition of algal organic matter (AOM) were studied using Chlorella vulgaris as a model species. In batch cultivation, flocculation was increasingly inhibited over time and mainly influenced by changes in medium composition, rather than biological changes at the cell surface. Total carbohydrate content of the organic matter fraction sized bigger than 3 kDa increased over time and this fraction was shown to be mainly responsible for the inhibition of alkaline flocculation. The monosaccharide identification of this fraction mainly showed the presence of neutral and anionic monosaccharides. The addition of 30-50 mg L(-1) alginic acid, as a model for anionic carbohydrate polymers containing uronic acids, resulted in a complete inhibition of flocculation. These results suggest that inhibition of alkaline flocculation was caused by interaction of anionic polysaccharides leading to an increased flocculant demand over time.

  13. Oxidative stress induced by a commercial glyphosate formulation in a tolerant strain of Chlorella kessleri.

    PubMed

    Romero, Delfina M; Ríos de Molina, María C; Juárez, Angela B

    2011-05-01

    We studied the toxicity of a glyphosate formulation and provide evidence of metabolic alterations due to oxidative stress caused in a Chlorella kessleri tolerant strain by exposure to the herbicide. After 96 h of exposure to increasing concentrations of the herbicide (0-70 mg L(-1)) with alkylaryl polyglycol ether surfactant, growth was inhibited (EC50-96 h 55.62 mg L(-1)). Glyphosate increased protein and malondialdehyde content which was significantly higher than in the control at 50-70 mg L(-1). Superoxide dismutase and catalase activities and reduced glutathione levels increased in a concentration-dependant manner. Morphological studies showed increases in vacuolisation and in cell and sporangia sizes. The glyphosate formulation studied has a cytotoxic effect on C. kessleri through a mechanism that would involve the induction of oxidative stress. Upon glyphosate exposure, oxidative stress parameters such as SOD and CAT activities and MDA level could be more sensitive biomarkers than usually tested growth parameters in C. kessleri. PMID:21074853

  14. Batch anaerobic co-digestion of waste activated sludge and microalgae (Chlorella sorokiniana) at mesophilic temperature.

    PubMed

    Beltrán, Carolina; Jeison, David; Fermoso, Fernando G; Borja, Rafael

    2016-08-23

    The microalgae Chlorella sorokiniana are used as co-substrate for waste activated sludge (WAS) anaerobic digestion. The specific objective of this research was to evaluate the feasibility of improving methane production from anaerobic digestion of WAS in co-digestion with this microalga, based on an optimized mixture percentage. Thus, the anaerobic co-digestion of both substrates aims to overcome the drawbacks of the anaerobic digestion of single WAS, simultaneously improving its management. Different co-digestion mixtures (0% WAS-100% microalgae; 25% WAS-75% microalgae; 50% WAS-50% microalgae; 75% WAS-25% microalgae; 100% WAS-0% microalgae) were studied. The highest methane yield (442 mL CH4/g VS) was obtained for the mixture with 75% WAS and 25% microalgae. This value was 22% and 39% higher than that obtained in the anaerobic digestion of the sole substrates WAS and microalgae, respectively, as well as 16% and 25% higher than those obtained for the co-digestion mixtures with 25% WAS and 75% microalgae and 50% WAS and 50% microalgae, respectively. The kinetic constant of the process increased 42%, 42% and 12%, respectively, for the mixtures with 25%, 50% and 75% of WAS compared to the substrate without WAS. Anaerobic digestion of WAS, together with C. sorokiniana, has been clearly improved by ensuring its viability, suitability and efficiency.

  15. Virus-host interactions: insights from the replication cycle of the large Paramecium bursaria chlorella virus.

    PubMed

    Milrot, Elad; Mutsafi, Yael; Fridmann-Sirkis, Yael; Shimoni, Eyal; Rechav, Katya; Gurnon, James R; Van Etten, James L; Minsky, Abraham

    2016-01-01

    The increasing interest in cytoplasmic factories generated by eukaryotic-infecting viruses stems from the realization that these highly ordered assemblies may contribute fundamental novel insights to the functional significance of order in cellular biology. Here, we report the formation process and structural features of the cytoplasmic factories of the large dsDNA virus Paramecium bursaria chlorella virus 1 (PBCV-1). By combining diverse imaging techniques, including scanning transmission electron microscopy tomography and focused ion beam technologies, we show that the architecture and mode of formation of PBCV-1 factories are significantly different from those generated by their evolutionary relatives Vaccinia and Mimivirus. Specifically, PBCV-1 factories consist of a network of single membrane bilayers acting as capsid templates in the central region, and viral genomes spread throughout the host cytoplasm but excluded from the membrane-containing sites. In sharp contrast, factories generated by Mimivirus have viral genomes in their core, with membrane biogenesis region located at their periphery. Yet, all viral factories appear to share structural features that are essential for their function. In addition, our studies support the notion that PBCV-1 infection, which was recently reported to result in significant pathological outcomes in humans and mice, proceeds through a bacteriophage-like infection pathway.

  16. Inhibition of alkaline flocculation by algal organic matter for Chlorella vulgaris.

    PubMed

    Vandamme, Dries; Beuckels, Annelies; Vadelius, Eric; Depraetere, Orily; Noppe, Wim; Dutta, Abhishek; Foubert, Imogen; Laurens, Lieve; Muylaert, Koenraad

    2016-01-01

    Alkaline flocculation is a promising strategy for the concentration of microalgae for bulk biomass production. However, previous studies have shown that biological changes during the cultivation negatively affect flocculation efficiency. The influence of changes in cell properties and in the quality and composition of algal organic matter (AOM) were studied using Chlorella vulgaris as a model species. In batch cultivation, flocculation was increasingly inhibited over time and mainly influenced by changes in medium composition, rather than biological changes at the cell surface. Total carbohydrate content of the organic matter fraction sized bigger than 3 kDa increased over time and this fraction was shown to be mainly responsible for the inhibition of alkaline flocculation. The monosaccharide identification of this fraction mainly showed the presence of neutral and anionic monosaccharides. The addition of 30-50 mg L(-1) alginic acid, as a model for anionic carbohydrate polymers containing uronic acids, resulted in a complete inhibition of flocculation. These results suggest that inhibition of alkaline flocculation was caused by interaction of anionic polysaccharides leading to an increased flocculant demand over time. PMID:26512808

  17. Optimization of culture media for large-scale lutein production by heterotrophic Chlorella vulgaris.

    PubMed

    Jeon, Jin Young; Kwon, Ji-Sue; Kang, Soon Tae; Kim, Bo-Ra; Jung, Yuchul; Han, Jae Gap; Park, Joon Hyun; Hwang, Jae Kwan

    2014-01-01

    Lutein is a carotenoid with a purported role in protecting eyes from oxidative stress, particularly the high-energy photons of blue light. Statistical optimization was performed to growth media that supports a higher production of lutein by heterotrophically cultivated Chlorella vulgaris. The effect of media composition of C. vulgaris on lutein was examined using fractional factorial design (FFD) and central composite design (CCD). The results indicated that the presence of magnesium sulfate, EDTA-2Na, and trace metal solution significantly affected lutein production. The optimum concentrations for lutein production were found to be 0.34 g/L, 0.06 g/L, and 0.4 mL/L for MgSO4 ·7H2 O, EDTA-2Na, and trace metal solution, respectively. These values were validated using a 5-L jar fermenter. Lutein concentration was increased by almost 80% (139.64 ± 12.88 mg/L to 252.75 ± 12.92 mg/L) after 4 days. Moreover, the lutein concentration was not reduced as the cultivation was scaled up to 25,000 L (260.55 ± 3.23 mg/L) and 240,000 L (263.13 ± 2.72 mg/L). These observations suggest C. vulgaris as a potential lutein source.

  18. Isolation of a novel lutein-protein complex from Chlorella vulgaris and its functional properties.

    PubMed

    Cai, Xixi; Huang, Qimin; Wang, Shaoyun

    2015-06-01

    A novel kind of lutein-protein complex (LPC) was extracted from heterotrophic Chlorella vulgaris through aqueous extraction. The purification procedure contained solubilization of thylakoid proteins by a zwitterionic detergent CHAPS, anion exchange chromatography and gel filtration chromatography. Both wavelength scanning and HPLC analysis confirmed that lutein was the major pigment of the protein-based complex, and the mass ratio of lutein and protein was determined to be 9.72 : 100. Besides showing lipid peroxidation inhibition activity in vitro, LPC exerted significant antioxidant effects against ABTS and DPPH radicals with IC50 of 2.90 and 97. 23 μg mL(-1), respectively. Meanwhile, in vivo antioxidant activity of the complex was evaluated using the mice hepatotoxicity model; LPC significantly suppressed the carbon tetrachloride-induced elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and decreased hepatic malondialdehyde (MDA) levels and the hepatosomatic index. Moreover, LPC could effectively restore the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the treated mice livers. Our findings further the progress in the research of natural protein-based lutein complexes, suggesting that LPC has the potential in hepatoprotection against chemical induced toxicity and in increasing the antioxidant capacity of the defense system in the human body.

  19. Acid-catalyzed hot-water extraction of lipids from Chlorella vulgaris.

    PubMed

    Park, Ji-Yeon; Oh, You-Kwan; Lee, Jin-Suk; Lee, Kyubock; Jeong, Min-Ji; Choi, Sun-A

    2014-02-01

    Acid-catalyzed hot-water treatment for efficient extraction of lipids from a wet microalga, Chlorella vulgaris, was investigated. For an initial fatty acids content of 381.6mg/g cell, the extracted-lipid yield with no heating and no catalyst was 83.2mg/g cell. Under a 1% H2SO4 concentration heated at 120°C for 60min, however, the lipid-extraction yield was 337.4mg/g cell. The fatty acids content, meanwhile, was 935mg fatty acid/g lipid. According to the severity index formula, 337.5mg/g cell of yield under the 1% H2SO4 concentration heated at 150°C for 8min, and 334.2mg/g cell of yield under the 0.5% H2SO4 concentration heated at 150°C for 16min, were obtained. The lipids extracted by acid-catalyzed hot-water treatment were converted to biodiesel. The biodiesel's fatty acid methyl ester (FAME) content after esterification of the microalgal lipids was increased to 79.2% by the addition of excess methanol and sulfuric acid.

  20. Evaluation of novel starch-deficient mutants of Chlorella sorokiniana for hyper-accumulation of lipids

    PubMed Central

    Vonlanthen, Sofie; Dauvillée, David; Purton, Saul

    2015-01-01

    When green algae are exposed to physiological stresses such as nutrient deprivation, growth is arrested and the cells channel fixed carbon instead into storage compounds, accumulating first starch granules and then lipid bodies containing triacylglycerides. In recent years there has been significant interest in the commercial exploitation of algal lipids as a sustainable source of biodiesel. Since starch and lipid biosynthesis involves the same C3 precursor pool, it has been proposed that mutations blocking starch accumulation should result in increased lipid yields, and indeed several studies have supported this. The fast-growing, thermotolerant alga Chlorella sorokiniana represents an attractive strain for industrial cultivation. We have therefore generated and characterized starch-deficient mutants of C. sorokiniana and determined whether lipid levels are increased in these strains under stress conditions. One mutant (ST68) is shown to lack isoamylase, whilst two others (ST3 and ST12) are defective in starch phosphorylase. However, we find no significant change in the accumulation or profile of fatty acids in these mutants compared to the wild-type, suggesting that a failure to accumulate starch per se is not sufficient for the hyper-accumulation of lipid, and that more subtle regulatory steps underlie the partitioning of carbon to the two storage products. PMID:26865991

  1. Effects of Escherichia coli on Mixotrophic Growth of Chlorella minutissima and Production of Biofuel Precursors

    PubMed Central

    Higgins, Brendan T.; VanderGheynst, Jean S.

    2014-01-01

    Chlorella minutissima was co-cultured with Escherichia coli in airlift reactors under mixotrophic conditions (glucose, glycerol, and acetate substrates) to determine possible effects of bacterial contamination on algal biofuel production. It was hypothesized that E. coli would compete with C. minutissima for nutrients, displacing algal biomass. However, C. minutissima grew more rapidly and to higher densities in the presence of E. coli, suggesting a symbiotic relationship between the organisms. At an initial 1% substrate concentration, the co-culture produced 200-587% more algal biomass than the axenic C. minutissima cultures. Co-cultures grown on 1% substrate consumed 23–737% more of the available carbon substrate than the sum of substrate consumed by E. coli and C. minutissima alone. At 1% substrate, total lipid and starch productivity were elevated in co-cultures compared to axenic cultures indicating that bacterial contamination was not detrimental to the production of biofuel precursors in this specific case. Bio-fouling of the reactors observed in co-cultures and acid formation in all mixotrophic cultures, however, could present challenges for scale-up. PMID:24805253

  2. Chlorella zofingiensis as an Alternative Microalgal Producer of Astaxanthin: Biology and Industrial Potential

    PubMed Central

    Liu, Jin; Sun, Zheng; Gerken, Henri; Liu, Zheng; Jiang, Yue; Chen, Feng

    2014-01-01

    Astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione), a high-value ketocarotenoid with a broad range of applications in food, feed, nutraceutical, and pharmaceutical industries, has been gaining great attention from science and the public in recent years. The green microalgae Haematococcus pluvialis and Chlorella zofingiensis represent the most promising producers of natural astaxanthin. Although H. pluvialis possesses the highest intracellular astaxanthin content and is now believed to be a good producer of astaxanthin, it has intrinsic shortcomings such as slow growth rate, low biomass yield, and a high light requirement. In contrast, C. zofingiensis grows fast phototrophically, heterotrophically and mixtrophically, is easy to be cultured and scaled up both indoors and outdoors, and can achieve ultrahigh cell densities. These robust biotechnological traits provide C. zofingiensis with high potential to be a better organism than H. pluvialis for mass astaxanthin production. This review aims to provide an overview of the biology and industrial potential of C. zofingiensis as an alternative astaxanthin producer. The path forward for further expansion of the astaxanthin production from C. zofingiensis with respect to both challenges and opportunities is also discussed. PMID:24918452

  3. Growth characteristics of Chlorella sorokiniana in airlift and bubble column photobioreactors.

    PubMed

    Kumar, Kanhaiya; Das, Debabrata

    2012-07-01

    The present study investigated the feasibility of bioCO(2) sequestration using Chlorella sorokiniana. It was found that 5% CO(2) (v/v) in air was the most suitable concentration for the growth of this organism. At this concentration, the maximum rate of CO(2) sequestered and the biomass obtained were found to be 1.21 g L(-1)d(-1) and 4.4 g L(-1) respectively. Modeling and simulation of the growth profile was obtained using the logistic equation. Further, at higher CO(2) concentrations, pH drop in the growth media, TAP [-acetate], was prevented by replacing NH(4)Cl by NaNO(3.) Additionally, the study evaluated the performance of two reactors namely: bubble column and airlift reactor based on their growth profile and transport properties like K(L)a and mixing time. The growth profile was better in airlift reactor and it provides cyclic axial mixing of media. K(L)a of downcomer was significantly lower than the riser in airlift reactor.

  4. Comparison between several methods of total lipid extraction from Chlorella vulgaris biomass.

    PubMed

    dos Santos, Raquel Rezende; Moreira, Daniel Mendonça; Kunigami, Claudete Norie; Aranda, Donato Alexandre Gomes; Teixeira, Cláudia Maria Luz Lapa

    2015-01-01

    The use of lipids obtained from microalgae biomass has been described as a promising alternative for production of biodiesel to replace petro-diesel. It involves steps such as the cultivation of microalgae, biomass harvesting, extraction and transesterification of lipids. The purpose of the present study was to compare different methods of extracting total lipids. These methods were tested in biomass of Chlorella vulgaris with the solvents ethanol, hexane and a mixture of chloroform:methanol in ratios 1:2 and 2:1. The solvents were associated with other mechanisms of cell disruption such as use of a Potter homogenizer and ultrasound treatment. The percentage of triglycerides in the total lipids was determinated by the glycerol-3-phosphate oxidase-p-chlorophenol method (triglycerides monoreagent K117; Bioclin). Among the tested methods, the mixture of chloroform:methanol (2:1) assisted by ultrasound was most efficient, extracting an average of 19% of total lipids, of which 55% were triglycerides. The gas chromatographic analysis did not show differences in methyl ester profiles of oils extracted under the different methods.

  5. Co-pyrolysis characteristics of microalgae Isochrysis and Chlorella: Kinetics, biocrude yield and interaction.

    PubMed

    Zhao, Bingwei; Wang, Xin; Yang, Xiaoyi

    2015-12-01

    Co-pyrolysis characteristics of Isochrysis (high lipid) and Chlorella (high protein) were investigated qualitatively and quantitatively based on DTG curves, biocrude yield and composition by individual pyrolysis and co-pyrolysis. DTG curves in co-pyrolysis have been compared accurately with those in individual pyrolysis. An interaction has been detected at 475-500°C in co-pyrolysis based on biocrude yields, and co-pyrolysis reaction mechanism appear three-dimensional diffusion in comparison with random nucleation followed by growth in individual pyrolysis based on kinetic analysis. There is no obvious difference in the maximum biocrude yields for individual pyrolysis and co-pyrolysis, but carboxylic acids (IC21) decreased and N-heterocyclic compounds (IC12) increased in co-pyrolysis. Simulation results of biocrude yield by Components Biofuel Model and Kinetics Biofuel Model indicate that the processes of co-pyrolysis comply with those of individual pyrolysis in solid phase by and large. Variation of percentage content in co-pyrolysis and individual pyrolysis biocrude indicated interaction in gas phase.

  6. Peculiarities of ultrastructure of Chlorella cells growing aboard the Bion-10 during 12 days

    NASA Astrophysics Data System (ADS)

    Popova, A. F.; Sytnik, K. M.

    The ultrastructure of Chlorella cells grown in darkness on a solid agar medium with organic additions aboard the Bion-1O biosatellite was studied. Certain differences in submicroscopic organization of organelles in the experimental cells were revealed compared to the Earth control. The changes are registered mainly in ultrastructure of energetic organelles - mitochondria and plastids of the experimental cells, in particular, an increase of mitochondria and their cristae size, as well as an increase of the total volume of mitochondrion per cell were established. The decrease of the starch amount in the plastid stroma and the electron density of the latter was also observed. In many experimental cells, the increase of condensed chromatin in the nuclei has been noted. Ultrastructural rearrangements in cells after laboratory experiment realized according to the thermogram registered aboard the Bion-10 were insignificant compared to the flight experiment. Data obtained are compared to results of space flight experiments carried out aboard the Bion-9 (polycomponent aquatic system) and the orbital station Mir (solid agar medium).

  7. Production of Biodiesel from Chlorella sp. Enriched with Oyster Shell Extracts

    PubMed Central

    Choi, Woon Yong; Kang, Do Hyung; Lee, Hyeon Yong

    2014-01-01

    This study investigated the cultivation of the marine microalga Chlorella sp. without supplying an inorganic carbon source, but instead with enriching the media with extracts of oyster shells pretreated by a high-pressure homogenization process. The pretreated oyster shells were extracted by a weak acid, acetic acid, that typically has harmful effects on cell growth and also poses environmental issues. The concentration of the residual dissolved carbon dioxide in the medium was sufficient to maintain cell growth at 32 ppm and pH 6.5 by only adding 5% (v/v) of oyster shell extracts. Under this condition, the maximum cell density observed was 2.74 g dry wt./L after 27 days of cultivation. The total lipid content was also measured as 18.1 (%, w/w), and this value was lower than the 23.6 (%, w/w) observed under nitrogen deficient conditions or autotrophic conditions. The fatty acid compositions of the lipids were also measured as 10.9% of C16:1 and 16.4% of C18:1 for the major fatty acids, which indicates that the biodiesel from this culture process should be a suitable biofuel. These results suggest that oyster shells, environmental waste from the food industry, can be used as a nutrient and carbon source with seawater, and this reused material should be important for easily scaling up the process for an outdoor culture system. PMID:24696841

  8. Comparison between several methods of total lipid extraction from Chlorella vulgaris biomass.

    PubMed

    dos Santos, Raquel Rezende; Moreira, Daniel Mendonça; Kunigami, Claudete Norie; Aranda, Donato Alexandre Gomes; Teixeira, Cláudia Maria Luz Lapa

    2015-01-01

    The use of lipids obtained from microalgae biomass has been described as a promising alternative for production of biodiesel to replace petro-diesel. It involves steps such as the cultivation of microalgae, biomass harvesting, extraction and transesterification of lipids. The purpose of the present study was to compare different methods of extracting total lipids. These methods were tested in biomass of Chlorella vulgaris with the solvents ethanol, hexane and a mixture of chloroform:methanol in ratios 1:2 and 2:1. The solvents were associated with other mechanisms of cell disruption such as use of a Potter homogenizer and ultrasound treatment. The percentage of triglycerides in the total lipids was determinated by the glycerol-3-phosphate oxidase-p-chlorophenol method (triglycerides monoreagent K117; Bioclin). Among the tested methods, the mixture of chloroform:methanol (2:1) assisted by ultrasound was most efficient, extracting an average of 19% of total lipids, of which 55% were triglycerides. The gas chromatographic analysis did not show differences in methyl ester profiles of oils extracted under the different methods. PMID:24910443

  9. Magnesium aminoclay enhances lipid production of mixotrophic Chlorella sp. KR-1 while reducing bacterial populations.

    PubMed

    Kim, Bohwa; Praveenkumar, Ramasamy; Lee, Jiye; Nam, Bora; Kim, Dong-Myung; Lee, Kyubock; Lee, Young-Chul; Oh, You-Kwan

    2016-11-01

    Improving lipid productivity and preventing overgrowth of contaminating bacteria are critical issues relevant to the commercialization of the mixotrophic microalgae cultivation process. In this paper, we report the use of magnesium aminoclay (MgAC) nanoparticles for enhanced lipid production from oleaginous Chlorella sp. KR-1 with simultaneous control of KR-1-associated bacterial growth in mixotrophic cultures with glucose as the model substrate. Addition of 0.01-0.1g/L MgAC promoted microalgal biomass production better than the MgAC-less control, via differential biocidal effects on microalgal and bacterial cells (the latter being more sensitive to MgAC's bio-toxicity than the former). The inhibition effect of MgAC on co-existing bacteria was, as based on density-gradient-gel-electrophoresis (DGGE) analysis, largely dosage-dependent and species-specific. MgAC also, by inducing an oxidative stress environment, increased both the cell size and lipid content of KR-1, resulting in a considerable, ∼25% improvement of mixotrophic algal lipid productivity (to ∼410mgFAME/L/d) compared with the untreated control.

  10. Extraction, fractionation and functional properties of proteins from the microalgae Chlorella vulgaris.

    PubMed

    Ursu, Alina-Violeta; Marcati, Alain; Sayd, Thierry; Sante-Lhoutellier, Véronique; Djelveh, Gholamreza; Michaud, Philippe

    2014-04-01

    This paper deals with the extraction and emulsifying properties of proteins from Chlorella vulgaris. Solubilisation of proteins has been achieved using high pressure cell disrupter under pH=7 or pH=12. The higher solubilisation yield (52±3%w/w) was obtained using a combination of alkaline conditions and mechanical treatments (2.7kbar). After solubilisation, proteins were recovered by two procedures: precipitation in acid media and concentration/fractionation by tangential ultrafiltration. Proteins were analysed for their molecular weights, isoelectric points and amino acids compositions and their emulsifying properties were quantified and compared to those of commercial ingredients. In spite of lower yield, better emulsifying capacity was obtained when protein solubilisation takes place at pH=7 and when using proteins from permeate of tangential ultrafiltration. In all cases, emulsifying capacity (1780±20 and 3090±50mLoil/g protein) and stability (72±1% and 79±1%) of microalgae proteins remained comparable or higher than the commercial ingredients such as sodium caseinate.

  11. Comparison of Chlorella vulgaris and cyanobacterial biomass: cultivation in urban wastewater and methane production.

    PubMed

    Mendez, Lara; Sialve, Bruno; Tomás-Pejó, Elia; Ballesteros, Mercedes; Steyer, Jean Philippe; González-Fernández, Cristina

    2016-05-01

    Anaerobic digestion of microalgae is hampered by its complex cell wall. Against this background, cyanobacteria cell walls render this biomass as an ideal substrate for overcoming this drawback. The aim of the present study was to compare the growth of two cyanobacteria (Aphanizomenon ovalisporum and Anabaena planctonica) and a microalga (Chlorella vulgaris) in urban wastewater when varying the temperature (22, 27 and 32 °C). Cyanobacterial optimal growth for both strains was attained at 22 °C, while C. vulgaris did not show remarkable differences among temperatures. For all the microorganisms, ammonium removal was higher than phosphate. Biomass collected was subjected to anaerobic digestion. Methane yield of C. vulgaris was 184.8 mL CH4 g COD in(-1) while with A. ovalisporum and A. planctonica the methane production was 1.2- and 1.4-fold higher. This study showed that cyanobacteria growth rates could be comparable to microalgae while presenting the additional benefit of an increased anaerobic digestibility.

  12. Subcritical Water Technology for Enhanced Extraction of Biochemical Compounds from Chlorella vulgaris

    PubMed Central

    Awaluddin, S. A.; Thiruvenkadam, Selvakumar; Izhar, Shamsul; Hiroyuki, Yoshida; Danquah, Michael K.; Harun, Razif

    2016-01-01

    Subcritical water extraction (SWE) technology has been used for the extraction of active compounds from different biomass materials with low process cost, mild operating conditions, short process times, and environmental sustainability. With the limited application of the technology to microalgal biomass, this work investigates parametrically the potential of subcritical water for high-yield extraction of biochemicals such as carbohydrates and proteins from microalgal biomass. The SWE process was optimized using central composite design (CCD) under varying process conditions of temperature (180–374°C), extraction time (1–20 min), biomass particulate size (38–250 μm), and microalgal biomass loading (5–40 wt.%). Chlorella vulgaris used in this study shows high volatile matter (83.5 wt.%) and carbon content (47.11 wt.%), giving advantage as a feedstock for biofuel production. The results showed maximum total carbohydrate content and protein yields of 14.2 g/100 g and 31.2 g/100 g, respectively, achieved under the process conditions of 277°C, 5% of microalgal biomass loading, and 5 min extraction time. Statistical analysis revealed that, of all the parameters investigated, temperature is the most critical during SWE of microalgal biomass for protein and carbohydrate production. PMID:27366748

  13. Synergistic dynamics of nitrogen and phosphorous influences lipid productivity in Chlorella minutissima for biodiesel production.

    PubMed

    Arora, Neha; Patel, Alok; Pruthi, Parul A; Pruthi, Vikas

    2016-08-01

    The study synergistically optimized nitrogen and phosphorous concentrations for attainment of maximum lipid productivity in Chlorella minutissima. Nitrogen and phosphorous limited cells (N(L)P(L)) showed maximum lipid productivity (49.1±0.41mg/L/d), 1.47 folds higher than control. Nitrogen depletion resulted in reduced cell size with large sized lipid droplets encompassing most of the intracellular space while discrete lipid bodies were observed under nitrogen sufficiency. Synergistic N/P starvations showed more prominent effect on photosynthetic pigments as to individual deprivations. Phosphorous deficiency along with N starvation exhibited 17.12% decline in carbohydrate while no change in nitrogen sufficient cells were recorded. The optimum N(L)P(L) concentration showed balance between biomass and lipid by maintaining intermediate cell size, pigments, carbohydrate and proteins. FAME profile showed C14-C18 carbon chains in N(L)P(L) cells with biodiesel properties comparable to plant oil methyl esters. Hence, synergistic N/P limitation was effective for enhancing lipid productivity with reduced consumption of nutrients.

  14. Optimization of culture media for large-scale lutein production by heterotrophic Chlorella vulgaris.

    PubMed

    Jeon, Jin Young; Kwon, Ji-Sue; Kang, Soon Tae; Kim, Bo-Ra; Jung, Yuchul; Han, Jae Gap; Park, Joon Hyun; Hwang, Jae Kwan

    2014-01-01

    Lutein is a carotenoid with a purported role in protecting eyes from oxidative stress, particularly the high-energy photons of blue light. Statistical optimization was performed to growth media that supports a higher production of lutein by heterotrophically cultivated Chlorella vulgaris. The effect of media composition of C. vulgaris on lutein was examined using fractional factorial design (FFD) and central composite design (CCD). The results indicated that the presence of magnesium sulfate, EDTA-2Na, and trace metal solution significantly affected lutein production. The optimum concentrations for lutein production were found to be 0.34 g/L, 0.06 g/L, and 0.4 mL/L for MgSO4 ·7H2 O, EDTA-2Na, and trace metal solution, respectively. These values were validated using a 5-L jar fermenter. Lutein concentration was increased by almost 80% (139.64 ± 12.88 mg/L to 252.75 ± 12.92 mg/L) after 4 days. Moreover, the lutein concentration was not reduced as the cultivation was scaled up to 25,000 L (260.55 ± 3.23 mg/L) and 240,000 L (263.13 ± 2.72 mg/L). These observations suggest C. vulgaris as a potential lutein source. PMID:24550199

  15. Isolation and algicidal characterization of Bowmanella denitrificans S088 against Chlorella vulgaris.

    PubMed

    Jiang, Xiao; Ren, Chunhua; Hu, Chaoqun; Zhao, Zhe

    2014-02-01

    One strain of algicidal bacterium, named as S088, was isolated from the intestine of healthy sea cucumbers (Stichopus horrens) in the South China Sea. Based on the analysis of its biochemical characteristics and 16S rDNA gene sequence, S088 was identified as Bowmanella denitrificans. Importantly, the algicidal activity of S088 on Chlorella vulgaris was characterized in this study. The initial densities of bacterial and algal cell showed strong influence on the removal rates of chlorophyll a. When the strain S088 was cultured under a complete darkness condition at 30 °C, its algicidal activity reached the highest level. Furthermore, it was found that the filtered supernatant from bacterial cultures had full algicidal activity, suggesting that the secreted compounds from S088 are involved in the observed algicidal action of S088. Moreover, the algicidal compounds were heat tolerant and had no cytotoxicity against fish cells, indicating that S088 would have a promising application as a safe probiotics for S. horrens. Finally, this is the first report about the algicidal activities in B. denitrificans.

  16. Changes in fatty acid composition of Chlorella vulgaris by hypochlorous acid.

    PubMed

    Park, Ji-Yeon; Choi, Sun-A; Jeong, Min-Ji; Nam, Bora; Oh, You-Kwan; Lee, Jin-Suk

    2014-06-01

    Hypochlorous acid treatment of a microalga, Chlorella vulgaris, was investigated to improve the quality of microalgal lipid and to obtain high biodiesel-conversion yield. Because chlorophyll deactivates the catalyst for biodiesel conversion, its removal in the lipid-extraction step enhances biodiesel productivity. When microalgae contacted the hypochlorous acid, chlorophyll was removed, and resultant changes in fatty acid composition of microalgal lipid were observed. The lipid-extraction yield after activated clay treatment was 32.7 mg lipid/g cell; after NaClO treatment at 0.8% available chlorine concentration, it was 95.2 mg lipid/g cell; and after NaCl electrolysis treatment at the 1 g/L cell concentration, it was 102.4 mg lipid/g cell. While the contents of all of the unsaturated fatty acids except oleic acid, in the microalgal lipid, decreased as the result of NaClO treatment, the contents of all of the unsaturated fatty acids including oleic acid decreased as the result of NaCl electrolysis treatment. PMID:24785789

  17. Enhanced biomass and oil production from sugarcane bagasse hydrolysate (SBH) by heterotrophic oleaginous microalga Chlorella protothecoides.

    PubMed

    Mu, Jinxiu; Li, Shitian; Chen, Di; Xu, Hua; Han, Fangxin; Feng, Bo; Li, Yuqin

    2015-06-01

    The potential use of sugarcane bagasse hydrolysate (SBH) for microalgal oil in a heterotrophic mode and the oil accumulation mechanisms by SBH-induced Chlorella protothecoides cells were investigated in this study. Results demonstrated that SBH performed better than glucose for cell growth and lipid accumulation under the same reducing sugar concentration. The lipid productivity of 0.69g/L/d was accomplished at 40g/L of reducing sugar by batch culture. Under the fed-batch culture condition, the maximum biomass and lipid productivity were 24.01g/L and 1.19g/L/d, respectively. Metabolic pathway analysis results indicated that xylose and arabinose involved in pentose phosphate pathway might be predominant over sole glucose involved in glycolysis for lipid accumulation in cells. Three metabolic checkpoints in the proposed metabolic network, including xylulose kinase, acyl-CoA dehydrogenase, and dihydrolipoyl dehydrogenase reveal new possibilities in developing genetic and metabolic engineering microalgae for desirable lipid productivity.

  18. Chlorella saccharophila cytochrome f and its involvement in the heat shock response

    PubMed Central

    Zuppini, Anna; Gerotto, Caterina; Moscatiello, Roberto; Bergantino, Elisabetta; Baldan, Barbara

    2009-01-01

    Cytochrome f is an essential component of the major redox complex of the thylakoid membrane. Cloning and characterization are presented here of a novel partial cDNA (ChspetA) encoding cytochrome f in the psychrophile unicellular green alga Chlorella saccharophila and its involvement in the heat shock (HS) response pathway has been analysed. Semi-quantitative reverse transcriptase PCR analysis showed that ChspetA expression is up-regulated in heat-shocked cells and the protein profile of cytochrome f highlighted a release of cytochrome f into the cytosol depending on the time lapse from the HS. Evans Blue assay, analysis of chromatin condensation, and chloroplast alterations showed the induction of cell death in cell suspensions treated with cytosolic extracts from heat-shocked cells. This study identifies cytochrome f in C. saccharophila that seems to be involved in the HS-induced programmed cell death process. The data suggest that cytochrome f fulfils its role through a modulation of its transcription and translation levels, together with its intracellular localization. This work focuses on a possible role of cytochrome f into the programmed cell death-like process in a unicellular chlorophyte and suggests the existence of chloroplast-mediated programmed cell death machinery in an organism belonging to one of the primary lineages of photosynthetic eukaryotes. PMID:19773387

  19. Combining and Comparing Coalescent, Distance and Character-Based Approaches for Barcoding Microalgaes: A Test with Chlorella-Like Species (Chlorophyta).

    PubMed

    Zou, Shanmei; Fei, Cong; Song, Jiameng; Bao, Yachao; He, Meilin; Wang, Changhai

    2016-01-01

    Several different barcoding methods of distinguishing species have been advanced, but which method is the best is still controversial. Chlorella is becoming particularly promising in the development of second-generation biofuels. However, the taxonomy of Chlorella-like organisms is easily confused. Here we report a comprehensive barcoding analysis of Chlorella-like species from Chlorella, Chloroidium, Dictyosphaerium and Actinastrum based on rbcL, ITS, tufA and 16S sequences to test the efficiency of traditional barcoding, GMYC, ABGD, PTP, P ID and character-based barcoding methods. First of all, the barcoding results gave new insights into the taxonomic assessment of Chlorella-like organisms studied, including the clear species discrimination and resolution of potentially cryptic species complexes in C. sorokiniana, D. ehrenbergianum and C. Vulgaris. The tufA proved to be the most efficient barcoding locus, which thus could be as potential "specific barcode" for Chlorella-like species. The 16S failed in discriminating most closely related species. The resolution of GMYC, PTP, P ID, ABGD and character-based barcoding methods were variable among rbcL, ITS and tufA genes. The best resolution for species differentiation appeared in tufA analysis where GMYC, PTP, ABGD and character-based approaches produced consistent groups while the PTP method over-split the taxa. The character analysis of rbcL, ITS and tufA sequences could clearly distinguish all taxonomic groups respectively, including the potentially cryptic lineages, with many character attributes. Thus, the character-based barcoding provides an attractive complement to coalescent and distance-based barcoding. Our study represents the test that proves the efficiency of multiple DNA barcoding in species discrimination of microalgaes.

  20. Combining and Comparing Coalescent, Distance and Character-Based Approaches for Barcoding Microalgaes: A Test with Chlorella-Like Species (Chlorophyta).

    PubMed

    Zou, Shanmei; Fei, Cong; Song, Jiameng; Bao, Yachao; He, Meilin; Wang, Changhai

    2016-01-01

    Several different barcoding methods of distinguishing species have been advanced, but which method is the best is still controversial. Chlorella is becoming particularly promising in the development of second-generation biofuels. However, the taxonomy of Chlorella-like organisms is easily confused. Here we report a comprehensive barcoding analysis of Chlorella-like species from Chlorella, Chloroidium, Dictyosphaerium and Actinastrum based on rbcL, ITS, tufA and 16S sequences to test the efficiency of traditional barcoding, GMYC, ABGD, PTP, P ID and character-based barcoding methods. First of all, the barcoding results gave new insights into the taxonomic assessment of Chlorella-like organisms studied, including the clear species discrimination and resolution of potentially cryptic species complexes in C. sorokiniana, D. ehrenbergianum and C. Vulgaris. The tufA proved to be the most efficient barcoding locus, which thus could be as potential "specific barcode" for Chlorella-like species. The 16S failed in discriminating most closely related species. The resolution of GMYC, PTP, P ID, ABGD and character-based barcoding methods were variable among rbcL, ITS and tufA genes. The best resolution for species differentiation appeared in tufA analysis where GMYC, PTP, ABGD and character-based approaches produced consistent groups while the PTP method over-split the taxa. The character analysis of rbcL, ITS and tufA sequences could clearly distinguish all taxonomic groups respectively, including the potentially cryptic lineages, with many character attributes. Thus, the character-based barcoding provides an attractive complement to coalescent and distance-based barcoding. Our study represents the test that proves the efficiency of multiple DNA barcoding in species discrimination of microalgaes. PMID:27092945

  1. [Study on the Visualization of the Biomass of Chlorella sp., Isochrysis galbana, and Spirulina sp. Based on Hyperspectral Imaging Technique].

    PubMed

    Jiang, Lu-lu; Wet, Xuan; Zhao, Yan-ru; Shao, Yong-ni; Qiu, Zheng-jun; He, Yong

    2016-03-01

    Effective cultivation of the microalgae is the key issue for microalgal bio-energy utilization. In nutrient rich culture conditions, the microalge have a fast growth rate, but they are more susceptible to environmental pollution and influence. So to monitor the the growth process of microalgae is significant during cultivating. Hyperspectral imaging has the advantages of both spectra and image analysis. The spectra contain abundant material quality signal and the image contains abundant spatial information of the material about the chemical distribution. It can achieve the rapid information acquisition and access a large amount of data. In this paper, the authors collected the hyperspectral images of forty-five samples of Chlorella sp., Isochrysis galbana, and Spirulina sp., respectively. The average spectra of the region of interest (ROI) were extracted. After applying successive projection algorithm (SPA), the authors established the multiple linear regression (MLR) model with the spectra and corresponding biomass of 30 samples, 15 samples were used as the prediction set. For Chlorella sp., Isochrysis galbana, and Spirulina sp., the correlation coefficient of prediction (r(pre)) are 0.950, 0.969 and 0.961, the root mean square error of prediction (RMSEP) for 0.010 2, 0.010 7 and 0.007 1, respectively. Finally, the authors used the MLR model to predict biomass for each pixel in the images of prediction set; images displayed in different colors for visualization based on pseudo-color images with the help of a Matlab program. The results show that using hyperspectral imaging technique to predict the biomass of Chlorella sp. and Spirulina sp. were better, but for the Isochrysis galbana visualization needs to be further improved. This research set the basis for rapidly detecting the growth of microalgae and using the microalgae as the bio-energy.

  2. [Study on the Visualization of the Biomass of Chlorella sp., Isochrysis galbana, and Spirulina sp. Based on Hyperspectral Imaging Technique].

    PubMed

    Jiang, Lu-lu; Wet, Xuan; Zhao, Yan-ru; Shao, Yong-ni; Qiu, Zheng-jun; He, Yong

    2016-03-01

    Effective cultivation of the microalgae is the key issue for microalgal bio-energy utilization. In nutrient rich culture conditions, the microalge have a fast growth rate, but they are more susceptible to environmental pollution and influence. So to monitor the the growth process of microalgae is significant during cultivating. Hyperspectral imaging has the advantages of both spectra and image analysis. The spectra contain abundant material quality signal and the image contains abundant spatial information of the material about the chemical distribution. It can achieve the rapid information acquisition and access a large amount of data. In this paper, the authors collected the hyperspectral images of forty-five samples of Chlorella sp., Isochrysis galbana, and Spirulina sp., respectively. The average spectra of the region of interest (ROI) were extracted. After applying successive projection algorithm (SPA), the authors established the multiple linear regression (MLR) model with the spectra and corresponding biomass of 30 samples, 15 samples were used as the prediction set. For Chlorella sp., Isochrysis galbana, and Spirulina sp., the correlation coefficient of prediction (r(pre)) are 0.950, 0.969 and 0.961, the root mean square error of prediction (RMSEP) for 0.010 2, 0.010 7 and 0.007 1, respectively. Finally, the authors used the MLR model to predict biomass for each pixel in the images of prediction set; images displayed in different colors for visualization based on pseudo-color images with the help of a Matlab program. The results show that using hyperspectral imaging technique to predict the biomass of Chlorella sp. and Spirulina sp. were better, but for the Isochrysis galbana visualization needs to be further improved. This research set the basis for rapidly detecting the growth of microalgae and using the microalgae as the bio-energy. PMID:27400526

  3. Differential effects of P25 TiO2 nanoparticles on freshwater green microalgae: Chlorella and Scenedesmus species.

    PubMed

    Roy, Rajdeep; Parashar, Abhinav; Bhuvaneshwari, M; Chandrasekaran, N; Mukherjee, Amitava

    2016-07-01

    P25 TiO2 nanoparticles majorly used in cosmetic products have well known detrimental effects towards the aquatic environment. In a freshwater ecosystem, Chlorella and Scenedesmus are among the most commonly found algal species frequently used to study the effects of metal oxide nanoparticles. A comparative study has been conducted herein to investigate differences in the toxic effects caused by these nanoparticles towards the two algae species. The three different concentrations of P25 TiO2 NPs (0.01, 0.1 & 1μg/mL, i.e., 0.12, 1.25 and 12.52μM) were selected to correlate surface water concentrations of the nanoparticles, and filtered and sterilized fresh water medium was used throughout this study. There was significant increase (p<0.001) in hydrodynamic diameter of nanoparticles with respect to both, time (0, 24, 48 and 72h) as well as concentration under all the exposure conditions. Although, significant dose-dependent morphological (surface area & biovolume) interspecies variations were not observed, it was evident at the highest concentration of exposure within individuals. At 1μg/mL exposure concentration, a significant difference in toxicity was noted between Chlorella and Scenedesmus under only visible light (p<0.001) and UVA (p<0.01) irradiation conditions. The viability data were well supported by the results obtained for oxidative stress induced by NPs on the cells. At the highest exposure concentration, superoxide dismutase and reduced glutathione activities were assessed for both the algae under all the irradiation conditions. Increased catalase activity and LPO release complemented the cytotoxic effects observed. Significant interspecies variations were noted for these parameters under UVA and visible light exposed cells of Chlorella and Scenedesmus species, which could easily be correlated with the uptake of the NPs. PMID:27137676

  4. Response of Mammalian Macrophages to Challenge with the Chlorovirus Acanthocystis turfacea Chlorella Virus 1

    PubMed Central

    Agarkova, Irina V.; Zhou, You; Yolken, Robert H.; Van Etten, James L.

    2015-01-01

    ABSTRACT It was recently reported that 44% of the oropharyngeal samples from the healthy humans in a study cohort had DNA sequences similar to that of the chlorovirus ATCV-1 (Acanthocystis turfacea chlorella virus 1, family Phycodnaviridae) and that these study subjects had decreases in visual processing and visual motor speed compared with individuals in whom no virus was detected. Moreover, mice inoculated orally with ATCV-1 developed immune responses to ATCV-1 proteins and had decreases in certain cognitive domains. Because heightened interleukin-6 (IL-6), nitric oxide (NO), and ERK mitogen-activated protein (MAP) kinase activation from macrophages are linked to cognitive impairments, we evaluated cellular responses and viral PFU counts in murine RAW264.7 cells and primary macrophages after exposure to ATCV-1 in vitro for up to 72 h after a virus challenge. Approximately 8% of the ATCV-1 inoculum was associated with macrophages after 1 h, and the percentage increased 2- to 3-fold over 72 h. Immunoblot assays with rabbit anti-ATCV-1 antibody detected a 55-kDa protein consistent with the viral capsid protein from 1 to 72 h and increasing de novo synthesis of a previously unidentified 17-kDa protein beginning at 24 h. Emergence of the 17-kDa protein did not occur and persistence of the 55-kDa protein declined over time when cells were exposed to heat-inactivated ATCV-1. Moreover, starting at 24 h, RAW264.7 cells exhibited cytopathic effects, annexin V staining, and cleaved caspase 3. Activation of ERK MAP kinases occurred in these cells by 30 min postchallenge, which preceded the expression of IL-6 and NO. Therefore, ATCV-1 persistence in and induction of inflammatory factors by these macrophages may contribute to declines in the cognitive abilities of mice and humans. IMPORTANCE Virus infections that persist in and stimulate inflammatory factors in macrophages contribute to pathologies in humans. A previous study showed that DNA sequences homologous to the

  5. Phospholipid Metabolism in an Industry Microalga Chlorella sorokiniana: The Impact of Inoculum Sizes

    PubMed Central

    Lu, Shuhuan; Wang, Jiangxin; Ma, Qian; Yang, Jie; Li, Xia; Yuan, Ying-Jin

    2013-01-01

    Chlorella sorokiniana is an important industry microalga potential for biofuel production. Inoculum size is one of the important factors in algal large-scale culture, and has great effects on the growth, lipid accumulation and metabolism of microalgae. As the first barrier of cell contents, membrane plays a vital role in algal inoculum-related metabolism. The knowledge of phospholipids, the main membrane component and high accumulation of phospholipids as the major content of total lipids mass in some microalgae, is necessary to understand the role of membrane in cell growth and metabolism under different inoculum density. Profiling of C. sorokiniana phospholipids with LC-MS led to the identification of 119 phospholipid species. To discover the phospholipid molecules most related to change of inoculum sizes, Partial Least Squares Discriminant Analysis (PLS-DA) was employed and the results revealed that inoculum sizes significantly affected phospholipid profiling. Phosphatidylglycerol (PG), phosphatidyl- ethanolamine (PE) and several phosphatidylcholine (PC) species might play an important role under our experimental conditions. Further analysis of these biomarkers indicated that cell membrane status of C. sorokiniana might play an important role in the adaption to the inoculum sizes. And the culture with inoculum size of 1×106 cells mL−1 presented the best membrane status with the highest content of PC and PG, and the lowest content of PE. We discovered that the inoculum size of 1×106 cells mL−1 might provide the best growth condition for C. sorokiniana. Also we proposed that PG, PE and several PC may play an important role in inoculum-related metabolism in C. sorokiniana, which may work through thylakoid membrane and photosynthetic pathway. Thus this study would provide more potential targets for metabolic engineering to improve biofuel production and productivity in microalgae. PMID:23940649

  6. Comparison of cell rupturing by ozonation and ultrasonication for algal lipid extraction from Chlorella vulgaris.

    PubMed

    Huang, Yuanxing; Hong, Andy; Zhang, Daofang; Li, Liang

    2014-01-01

    Cell disruption is essential for lipid collection from cultivated microalgae. This study examines the performance of ultrasonication (US), conventional bubbling ozonation (CBO), and pressure-assisted ozonation (PAO) as a cell rupturing technique to obtain algal lipid from a freshwater unicellular microalgae Chlorella vulgaris, which was grown in BG11 medium at a temperature of 25 degrees C and illuminated by artificial lighting with light/dark cycle of 12 h/12 h. Changes in total organic carbon, total nitrogen, total phosphorous, and chlorophyll contents in the algae suspension after ozonation and US treatments were measured to evaluate the effectiveness of cell rupture by these techniques. Lipid yields of 21 and 27 g/100 g biomass were obtained using US and PAO, respectively. Lipid yields of about 5 g/100 g biomass were obtained using CBO. In all rupturing treatments, C16 and C18 compounds were found to be predominant accounting for 90% of the fatty acids. Using US for rupturing, fatty acids of C 16:0, C18:1, and C18:2 were predominant, accounting for 76 +/- 4.2% of all the fatty acids. Using CBO and PAO involving ozone, fatty acids of C16:0 and C18:0 were predominant, accounting for 63-94% of the products. The results suggest that saturated fatty acid methyl ester (FAME) products are predominant with oxidative ozonation rupturing while unsaturated FAME products of lower-melting points predominant with physical ultrasonic rupturing means. PAO was an effective cell rupture method for biodiesel production with high lipid yield and more saturated hydrocarbon products.

  7. Effect of biochemical stimulants on biomass productivity and metabolite content of the microalga, Chlorella sorokiniana.

    PubMed

    Hunt, Ryan W; Chinnasamy, Senthil; Bhatnagar, Ashish; Das, K C

    2010-12-01

    The influence of 12 biochemical stimulants, namely 2-phenylacetic acid (PAA; 30 ppm), indole-3 butyric acid (IBA; 10 ppm), 1-naphthaleneacetic acid (NAA; 2.5, 5 and 10 ppm ), gibberellic acid (GA3, 10 ppm), zeatin (ZT; 0.002 ppm), thidiazuron (0.22 ppm), humic acid (20 ppm), kelp extract (250 ppm), methanol (500 ppm), ferric chloride (3.2 ppm ), putrescine (0.09 ppm), spermidine (1.5 ppm) were prescreened for their impact on growth and chlorophyll for the green alga--Chlorella sorokiniana. C. sorokiniana responded best to phytohormones in the auxin family, particularly NAA. Thereafter, two studies were conducted on combinations of phytohormones to compare blends from within the auxin family as well as against other families. These treatments were NAA(₅ ppm)+PAA(₃₀ ppm), NAA(₂.₅ ppm)+PAA(₁₅ ppm), NAA(₅ ppm)+IBA(₁₀ ppm), NAA(₅ ppm)+GA3(₁₀ ppm), NAA(₅ ppm)+ZT(₁ ppm), and NAA(₅ ppm)+GA3(₁₀ ppm)+ZT(₁ ppm). Combinations of NAA with other auxins did not have synergistic or antagonistic effects on the growth. However, combinations of compounds from different phytohormone families, such as NAA(₅ ppm)+GA3(₁₀ ppm)+ZT(₁ ppm), dramatically increased the biomass productivity by 170% over the control followed by the treatments: NAA(₅ ppm)+GA3(₁₀ ppm) (138%), NAA(₅ ppm)+ZT(₁ ppm) (136%), and NAA(₅ ppm) ( 133%). The effect of biochemical stimulants were also measured on metabolites such as chlorophyll, protein, and lipids in C. sorokiniana. Renewed interest in microalgae for biotechnology and biofuel applications may warrant the use of biochemical stimulants for cost reduction in large-scale cultivation through increased biomass productivity. PMID:20596899

  8. Chlorella vulgaris culture as a regulator of CO2 in a bioregenerative life support system

    NASA Astrophysics Data System (ADS)

    Li, Ming; Hu, Dawei; Liu, Hong; Hu, Enzhu; Xie, Beizhen; Tong, Ling

    2013-08-01

    It is the primary task for a bioregenerative life support system (BLSS) to maintain the stable concentrations of CO2 and O2. However, these concentrations could fluctuate based on various factors, such as the imbalance between respiration/assimilation quotients of the heterotrophic and autotrophic components. They can even be out of balance through catastrophic failure of higher plants in the emergency conditions. In this study, the feasibility of using unicellular Chlorella vulgaris of typically rapid growth as both “compensatory system” and “regulator” to control the balance of CO2 and O2 was analyzed in a closed ecosystem. For this purpose, a small closed ecosystem called integrative experimental system (IES) was established in our laboratory where we have been conducting multi-biological life support system experiments (MLSSE). The IES consists of a closed integrative cultivating system (CICS) and a plate photo-bioreactor. Four volunteers participated in the study for gas exchange by periodical breathing through a tube connected with the CICS. The plate photo-bioreactor was used to cultivate C. vulgaris. Results showed that the culture of C. vulgaris could be used in a situation of catastrophic failure of higher plant under the emergencies. And the productivity could recover itself to the original state in 3 to 5 days to protect the system till the higher plant was renewed. Besides, C. vulgaris could grow well and the productivity could be affected by the light intensity which could help to keep the balance of CO2 and O2 in the IES efficiently. Thus, C. vulgaris could be included in the design of a BLSS as a “compensatory system” in the emergency contingency and a “regulator” during the normal maintenance.

  9. Single and mixture toxicity of pharmaceuticals and chlorophenols to freshwater algae Chlorella vulgaris.

    PubMed

    Geiger, Elisabeth; Hornek-Gausterer, Romana; Saçan, Melek Türker

    2016-07-01

    Organisms in the aquatic environment are exposed to a variety of substances of numerous chemical classes. The unintentional co-occurrence of pharmaceuticals and other contaminants of emerging concern may pose risk to non-target organisms. In this study, individual and binary mixture toxicity experiments of selected pharmaceuticals (ibuprofen and ciprofloxacin) and chlorophenols (2.4-dichlorophenol (2,4-DCP) and 3-chlorophenol (3-CP)) have been performed with freshwater algae Chlorella vulgaris. All experiments have been carried out according to the 96-h algal growth inhibition test OECD No. 201. Binary mixture tests were conducted using proportions of the respective IC50s in terms of toxic unit (TU). The mixture concentration-response curve was compared to predicted effects based on both the concentration addition (CA) and the independent action (IA) model. Additionally, the Combination Index (CI)-isobologram equation method was used to assess toxicological interactions of the binary mixtures. All substances individually tested had a significant effect on C. vulgaris population density and revealed IC50 values <100mgL(-1) after exposure period of 96-h. The toxic ranking of these four compounds to C. vulgaris was 2,4-DCP>ciprofloxacin>3-CP>ibuprofen. Generally, it can be concluded from this study that toxic mixture effects of all tested chemicals to C. vulgaris are higher than the individual effect of each mixture component. It could be demonstrated that IC50 values of the tested mixtures predominately lead to additive effects. The CA model is appropriate to estimate mixture toxicity, while the IA model tends to underestimate the joint effect. The CI-isobologram equation method predicted the mixtures accurately and elicited synergism at low effect levels for the majority of tested combinations. PMID:27045919

  10. CO2 Biofixation and Growth Kinetics of Chlorella vulgaris and Nannochloropsis gaditana.

    PubMed

    Adamczyk, Michał; Lasek, Janusz; Skawińska, Agnieszka

    2016-08-01

    CO2 biofixation was investigated using tubular bioreactors (15 and 1.5 l) either in the presence of green algae Chlorella vulgaris or Nannochloropsis gaditana. The cultivation was carried out in the following conditions: temperature of 25 °C, inlet-CO2 of 4 and 8 vol%, and artificial light enhancing photosynthesis. Higher biofixation were observed in 8 vol% CO2 concentration for both microalgae cultures than in 4 vol%. Characteristic process parameters such as productivity, CO2 fixation, and kinetic rate coefficient were determined and discussed. Simplified and advanced methods for determination of CO2 fixation were compared. In a simplified method, it is assumed that 1 kg of produced biomass equals 1.88 kg recycled CO2. Advance method is based on empirical results of the present study (formula with carbon content in biomass). It was observed that application of the simplified method can generate large errors, especially if the biomass contains a relatively low amount of carbon. N. gaditana is the recommended species for CO2 removal due to a high biofixation rate-more than 1.7 g/l/day. On day 10 of cultivation, the cell concentration was more than 1.7 × 10(7) cells/ml. In the case of C. vulgaris, the maximal biofixation rate and cell concentration did not exceed 1.4 g/l/day and 1.3 × 10(7) cells/ml, respectively. PMID:27052208

  11. Adjusting irradiance to enhance growth and lipid production of Chlorella vulgaris cultivated with monosodium glutamate wastewater.

    PubMed

    Jiang, Liqun; Ji, Yan; Hu, Wenrong; Pei, Haiyan; Nie, Changliang; Ma, Guixia; Song, Mingming

    2016-09-01

    Light is one of the most important factors affecting microalgae growth and biochemical composition. The influence of illumination on Chlorella vulgaris cultivated with diluted monosodium glutamate wastewater (MSGW) was investigated. Six progressive illumination intensities (0, 30, 90, 150, 200 and 300μmol·m(-2)s(-1)), were used for C. vulgaris cultivation at 25°C. Under 150μmol·m(-2)s(-1), the corresponding specific light intensity of 750×10(-6)μmol·m(-2)s(-1) per cell, algae obtained the maximum biomass concentration (1.46g·L(-1)) on the 7th day, which was 3.5 times of that under 0μmol·m(-2)s(-1), and the greatest average specific growth rate (0.79 d(-1)) in the first 7days. The results showed the importance role of light in mixotrophic growth of C. vulgaris. High light intensities of 200 and 300μmol·m(-2)s(-1) would inhibit microalgae growth to a certain degree. The algal lipid content was the greatest (30.5%) at 150μmol·m(-2)s(-1) light intensity, which was 2.42 times as high as that cultured in dark. The protein content of C. vulgaris decreased at high light intensities of 200 and 300μmol·m(-2)s(-1). The effect of irradiance on carbohydrate content was inversely correlated with that on protein. The available light at an appropriate intensity, not higher than 200μmol·m(-2)s(-1), was feasible for economical cultivation of C. vulgaris in MSGW. PMID:27484967

  12. Biological CO2 fixation using Chlorella vulgaris and its thermal characteristics through thermogravimetric analysis.

    PubMed

    Razzak, Shaikh A; Ali, Saad Aldin M; Hossain, Mohammad M; Mouanda, Alexis Nzila

    2016-11-01

    The present research is focused on cultivation of microalgae strain Chlorella vulgaris for bio-fixation of CO2 coupled with biomass production. In this regard, a single semi-batch vertical tubular photobioreactor and four similar photobioreactors in series have been employed. The concentration of CO2 in the feed stream was varied from 2 to 12 % (v/v) by adjusting CO2 to air ratio. The amount of CO2 capture and algae growth were monitored by measuring decrease of CO2 concentration in the gas phase, microalgal cell density, and algal biomass production rate. The results show that 4 % CO2 gives maximum amount of biomass (0.9 g L(-1)) and productivity (0.118 g L(-1) day(-1)) of C. vulgaris in a single reactor. In series reactors, average productivity per reactor found to be 0.078 g L(-1) day(-1). The maximum CO2 uptake for single reactor also found with 4 % CO2, and it is around 0.2 g L(-1) day(-1). In series reactors, average CO2 uptake is 0.13 g L(-1) day(-1) per reactor. TOC analysis shows that the carbon content of the produced biomass is around 40.67 % of total weight. The thermochemical characteristics of the cultivated C. vulgaris samples were analyzed in the presence of air. All samples burn above 200 °C and the combustion rate become faster at around 600 °C. Almost 98 wt% of the produced biomass is combustible in this range. PMID:27307068

  13. Optimising the bioreceptivity of porous glass tiles based on colonization by the alga Chlorella vulgaris.

    PubMed

    Ferrándiz-Mas, V; Bond, T; Zhang, Z; Melchiorri, J; Cheeseman, C R

    2016-09-01

    Green façades on buildings can mitigate greenhouse gas emissions. An option to obtain green facades is through the natural colonisation of construction materials. This can be achieved by engineering bioreceptive materials. Bioreceptivity is the susceptibility of a material to be colonised by living organisms. The aim of this research was to develop tiles made by sintering granular waste glass that were optimised for bioreceptivity of organisms capable of photosynthesis. Tiles were produced by pressing recycled soda-lime glass with a controlled particle size distribution and sintering compacted samples at temperatures between 680 and 740°C. The primary bioreceptivity of the tiles was evaluated by quantifying colonisation by the algae Chlorella vulgaris (C. vulgaris), which was selected as a model photosynthetic micro-organism. Concentrations of C. vulgaris were measured using chlorophyll-a extraction. Relationships between bioreceptivity and the properties of the porous glass tile, including porosity, sorptivity, translucency and pH are reported. Capillary porosity and water sorptivity were the key factors influencing the bioreceptivity of porous glass. Maximum C. vulgaris growth and colonisation was obtained for tiles sintered at 700°C, with chlorophyll-a concentrations reaching up to 11.1±0.4μg/cm(2) of tile. Bioreceptivity was positively correlated with sorptivity and porosity and negatively correlated with light transmittance. The research demonstrates that the microstructure of porous glass, determined by the processing conditions, significantly influences bioreceptivity. Porous glass tiles with high bioreceptivity that are colonised by photosynthetic algae have the potential to form carbon-negative façades for buildings and green infrastructure. PMID:27135568

  14. Candida utilis and Chlorella vulgaris Counteract Intestinal Inflammation in Atlantic Salmon (Salmo salar L.)

    PubMed Central

    Grammes, Fabian; Reveco, Felipe Eduardo; Romarheim, Odd Helge; Landsverk, Thor; Mydland, Liv Torunn; Øverland, Margareth

    2013-01-01

    Intestinal inflammation, caused by impaired intestinal homeostasis, is a serious condition in both animals and humans. The use of conventional extracted soybean meal (SBM) in diets for Atlantic salmon and several other fish species is known to induce enteropathy in the distal intestine, a condition often referred to as SBM induced enteropathy (SBMIE). In the present study, we investigated the potential of different microbial ingredients to alleviate SBMIE in Atlantic salmon, as a model of feed-induced inflammation. The dietary treatments consisted of a negative control based on fish meal (FM), a positive control based on 20% SBM, and four experimental diets combining 20% SBM with either one of the three yeasts Candida utilis (CU), Kluyveromyces marxianus (KM), Saccharomyces cerevisiae (SC) or the microalgae Chlorella vulgaris (CV). Histopathological examination of the distal intestine showed that all fish fed the SC or SBM diets developed characteristic signs of SBMIE, while those fed the FM, CV or CU diets showed a healthy intestine. Fish fed the KM diet showed intermediate signs of SBMIE. Corroborating results were obtained when measuring the relative length of PCNA positive cells in the crypts of the distal intestine. Gene set enrichment analysis revealed decreased expression of amino acid, fat and drug metabolism pathways as well as increased expression of the pathways for NOD-like receptor signalling and chemokine signalling in both the SC and SBM groups while CV and CU were similar to FM and KM was intermediate. Gene expression of antimicrobial peptides was reduced in the groups showing SBMIE. The characterisation of microbial communities using PCR-DGGE showed a relative increased abundance of Firmicutes bacteria in fish fed the SC or SBM diets. Overall, our results show that both CU and CV were highly effective to counteract SBMIE, while KM had less effect and SC had no functional effects. PMID:24386162

  15. Biological CO2 fixation using Chlorella vulgaris and its thermal characteristics through thermogravimetric analysis.

    PubMed

    Razzak, Shaikh A; Ali, Saad Aldin M; Hossain, Mohammad M; Mouanda, Alexis Nzila

    2016-11-01

    The present research is focused on cultivation of microalgae strain Chlorella vulgaris for bio-fixation of CO2 coupled with biomass production. In this regard, a single semi-batch vertical tubular photobioreactor and four similar photobioreactors in series have been employed. The concentration of CO2 in the feed stream was varied from 2 to 12 % (v/v) by adjusting CO2 to air ratio. The amount of CO2 capture and algae growth were monitored by measuring decrease of CO2 concentration in the gas phase, microalgal cell density, and algal biomass production rate. The results show that 4 % CO2 gives maximum amount of biomass (0.9 g L(-1)) and productivity (0.118 g L(-1) day(-1)) of C. vulgaris in a single reactor. In series reactors, average productivity per reactor found to be 0.078 g L(-1) day(-1). The maximum CO2 uptake for single reactor also found with 4 % CO2, and it is around 0.2 g L(-1) day(-1). In series reactors, average CO2 uptake is 0.13 g L(-1) day(-1) per reactor. TOC analysis shows that the carbon content of the produced biomass is around 40.67 % of total weight. The thermochemical characteristics of the cultivated C. vulgaris samples were analyzed in the presence of air. All samples burn above 200 °C and the combustion rate become faster at around 600 °C. Almost 98 wt% of the produced biomass is combustible in this range.

  16. CO2 Biofixation and Growth Kinetics of Chlorella vulgaris and Nannochloropsis gaditana.

    PubMed

    Adamczyk, Michał; Lasek, Janusz; Skawińska, Agnieszka

    2016-08-01

    CO2 biofixation was investigated using tubular bioreactors (15 and 1.5 l) either in the presence of green algae Chlorella vulgaris or Nannochloropsis gaditana. The cultivation was carried out in the following conditions: temperature of 25 °C, inlet-CO2 of 4 and 8 vol%, and artificial light enhancing photosynthesis. Higher biofixation were observed in 8 vol% CO2 concentration for both microalgae cultures than in 4 vol%. Characteristic process parameters such as productivity, CO2 fixation, and kinetic rate coefficient were determined and discussed. Simplified and advanced methods for determination of CO2 fixation were compared. In a simplified method, it is assumed that 1 kg of produced biomass equals 1.88 kg recycled CO2. Advance method is based on empirical results of the present study (formula with carbon content in biomass). It was observed that application of the simplified method can generate large errors, especially if the biomass contains a relatively low amount of carbon. N. gaditana is the recommended species for CO2 removal due to a high biofixation rate-more than 1.7 g/l/day. On day 10 of cultivation, the cell concentration was more than 1.7 × 10(7) cells/ml. In the case of C. vulgaris, the maximal biofixation rate and cell concentration did not exceed 1.4 g/l/day and 1.3 × 10(7) cells/ml, respectively.

  17. Growth-inhibitory and metal-binding proteins in Chlorella vulgaris exposed to cadmium or zinc.

    PubMed

    Huang, Zhiyong; Li, Lianping; Huang, Gaoling; Yan, Qingpi; Shi, Bing; Xu, Xiaoqin

    2009-01-18

    Phytochelatins, with the general structure of (gamma-Glu-Cys)n-Gly (n=2-11), are usually recognized as being strongly induced by metals in microalgae and play an important role in the detoxification of heavy metals in environment. However, there have been few studies on metallothionein (MT) synthesis in Chlorella vulgaris (C. vulgaris) exposed to heavy metals. The present study describes the growth inhibition of C. vulgaris exposed to different concentrations of cadmium and zinc, and the induction of metal-binding MT-like proteins in the cells. The amounts of metal-binding proteins, induced in the alga exposed to different concentrations of Cd and Zn, were analyzed with a size-exclusion HPLC coupled to ICP-MS. After being purified with a gel filtration column (Sephadex G-75, 3.5cmx80cm) and a desalting column (G-25, 1.5cmx30cm), the isoforms and sub-isoforms of Zn-binding protein were characterized by a reverse phase-HPLC coupled to electrospray ionization and a triple quadrupole mass spectrometer (HPLC-ESI-MS/MS). In addition, the ultraviolet spectra of purified Zn-binding proteins were analyzed in media with different pH values. The results showed that the significant inhibitory effects (at p<0.05) on the cell growth were observed when excessive metals such as 80micromoll(-1) of Cd, and 60 and 80micromoll(-1) of Zn were added. The Cd/Zn-binding proteins induced in C. vulgaris exposed to Cd and Zn were referred to as Cd/Zn-MT-like proteins in which the mean molecular mass of the apo-MT-like was 6152Da. The induced Cd/Zn-MT-like proteins might be involved in the detoxification of heavy metals, such as cadmium and zinc, by the alga. PMID:19019465

  18. Impact of zinc acclimation on bioaccumulation and homeostasis in Chlorella kesslerii.

    PubMed

    Hassler, Christel S; Behra, Renata; Wilkinson, Kevin J

    2005-08-30

    Growth curves, cellular Zn contents and cellular protein expression were examined for the green alga, Chlorella kesslerii, as a function of different Zn growth regimes (growth in 16 pM, 1.7 nM or 1.6 microM calculated Zn2+). Zn homeostasis was responsible for observed differences in the capacity of the organism to accumulate Zn. The rapid acclimation that occurred in response to a Zn deficiency was likely due to the production of Zn transport sites. No differences were observed among cellular phytochelatin contents or efflux rate constants, although efflux did play an important role in regulating Zn cellular content. A long-term adaptation to Zn was not thought to occur since bioaccumulation and biological responses were similar for four successive cultures (30-40 days, 16-19 cell cycles) at different [Zn2+]. Among proteins that were influenced by the Zn growth regime, the Rubisco and histone H3 proteins were identified as being induced in the presence of 1.6 microM Zn2+ as compared with 1.7 nM Zn2+. The impact of the Zn preconditioning demonstrated that the concentrations of essential metals in the algal growth media would have an important, if not predominant effect on toxicity or bioaccumulation assessments. Furthermore, the high regulation of Zn transport and intracellular events by the microorganisms will likely preclude the use of simple metal uptake models including the free ion activity model and the biotic ligand model to predict either bioaccumulation or toxicological effects of Zn and perhaps other essential metals. PMID:15993955

  19. Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis.

    PubMed

    Zhou, Qiongzhi; Li, Feng; Ge, Fei; Liu, Na; Kuang, Yangduo

    2016-10-01

    Toxicants are generally harmful to biotechnology in wastewater treatment. However, trace toxicant can induce microbial hormesis, but to date, it is still unknown how this phenomenon affects nutrient removal during municipal wastewater treatment process. Therefore, this study focused on the effects of hormesis induced by cetyltrimethyl ammonium bromide (CTAB), a representative quaternary ammonium cationic surfactant, on nutrient removal by Chlorella vulgaris F1068. Results showed that when the concentration of CTAB was less than 10 ng/L, the cellular components chlorophyll a, proteins, polysaccharides, and total lipids increased by 10.11, 58.17, 38.78, and 11.87 %, respectively, and some enzymes in nutrient metabolism of algal cells, such as glutamine synthetase (GS), acid phosphatase (ACP), H(+)-ATPase, and esterase, were also enhanced. As a result, the removal efficiencies of ammonia nitrogen (NH4 (+)) and total phosphorus (TP) increased by 14.66 and 8.51 %, respectively, compared to the control during a 7-day test period. The underlying mechanism was mainly due to an enhanced photosynthetic activity of C. vulgaris F1068 indicated by the increase in chlorophyll fluorescence parameters (the value of Fv/Fm, ΦII, Fv/Fo, and rETR increased by 12.99, 7.56, 25.59, and 8.11 %, respectively) and adenylate energy charge (AEC) (from 0.68 to 0.72). These results suggest that hormesis induced by trace toxicants could enhance the nutrient removal, which would be further considered in the design of municipal wastewater treatment processes. Graphical abstract The schematic mechanism of C. vulgaris F1068 under CTAB induced hormesis. Green arrows ( ) represent the increase and the red arrow ( ) represents the decrease.

  20. Biomass production and nutrient removal by Chlorella sp. as affected by sludge liquor concentration.

    PubMed

    Åkerström, Anette M; Mortensen, Leiv M; Rusten, Bjørn; Gislerød, Hans Ragnar

    2014-11-01

    The use of microalgae for biomass production and nutrient removal from the reject water produced in the dewatering process of anaerobically digested sludge, sludge liquor, was investigated. The sludge liquor was characterized by a high content of total suspended solids (1590 mg L(-1)), a high nitrogen concentration (1210 mg L(-1)), and a low phosphorus concentration (28 mg L(-1)). Chlorella sp. was grown in sludge liquor diluted with wastewater treatment plant effluent water to different concentrations (12, 25, 40, 50, 70, and 100%) using batch mode. The environmental conditions were 25 °C, a continuous lightning of 115 μmol m(-2) s(-1), and a CO2 concentration of 3.0%. The highest biomass production (0.42-0.45 g dry weight L(-1) Day(-1)) was achieved at 40-50% sludge liquor, which was comparable to the production of the control culture grown with an artificial fertilizer. The biomass production was 0.12 and 0.26 g dry weight L(-1) Day(-1) at 12% and 100% sludge liquor, respectively. The percentage of nitrogen in the algal biomass increased from 3.6% in 12% sludge liquor and reached a saturation of ∼10% in concentrations with 50% sludge liquor and higher. The phosphorus content in the biomass increased linearly from 0.2 to 1.5% with increasing sludge liquor concentrations. The highest nitrogen removal rates by algal biosynthesis were 33.6-42.6 mg TN L(-1) Day(-1) at 40-70% sludge liquor, while the highest phosphorus removal rates were 3.1-4.1 mg TP L(-1) Day(-1) at 50-100% sludge liquor. PMID:24935023

  1. Effect of Nutrient Starvation under High Irradiance on Lipid and Starch Accumulation in Chlorella fusca (Chlorophyta).

    PubMed

    Jerez, Celia G; Malapascua, José R; Sergejevová, Magda; Figueroa, Félix L; Masojídek

    2016-02-01

    The effect of nitrogen and sulphur limitation under high irradiance (PAR) was studied in the green microalga Chlorella fusca (Chlorophyta) in order to follow lipid and/or starch accumulation. Growth, biomass composition and the changes in photosynthetic activity (in vivo chlorophyll a fluorescence) were followed in the trials. The full nutrient culture showed high biomass production and starch accumulation at Day 1, when photosynthetic activity was high. Gradual deprivation (no nutrients added) became evident when photosynthesis was significantly suppressed (Day 3 onwards), which entailed a decrease of maximum relative electron transport rate (rETRmax) and increase of non-photochemical quenching (NPQ), accompanied by the onset of lipid accumulation and decline in starch content. In N- and S-starved cultures, rETRmax significantly decreased by Day 3, which caused a substantial drop in biomass production, cell number, biovolume and induction of lipid and starch accumulation. High starch content (45-50 % of DW) was found at the initial stage in full nutrient culture and at the stationary phase in nutrient-starved cultures. By the end of the trial, all treatments showed high lipid content (~30 % of DW). The full nutrient culture had higher biomass yield than starved treatments although starch (~0.2 g L(-1) day(-1)) and lipid (~0.15 g L(-1) day(-1) productivities were fairly similar in all the cultures. Our results showed that we could enrich biomass of C. fusca (% DW) in lipids using a two-stage strategy (a nutrient replete stage followed by gradual nutrient limitation) while under either procedure, N- or S-starvation, both high lipid and starch contents could be achieved.

  2. Regulation of accumulation and turnover of an inducible glutamate dehydrogenase in synchronous cultures of Chlorella.

    PubMed Central

    Israel, D W; Gronostajski, R M; Yeung, A T; Schmidt, R R

    1977-01-01

    Earlier studies indicated that the gene of an ammonium-inducible glutamate dehydrogenase (GDH) was inducible throughout the cell cycle and was expressible shortly after replication early in the S-phase in synchronous Chlorella cells growing at a rate of 13% per h in the absence of inducer. In the present study, synchronous cells cultured at the same growth rate in the continuous presence of inducer accumulated this enzyme in a linear manner, with a positive rate change observed late instead of early in the S-phase. At a growth rate of 26% per h, the positive rate change appeared to be displaced to 1.5 h before the S-phase in the next cell cycle. With 2'-deoxyadenosine, an in vivo inhibitor of deoxyribonucleic acid (DNA) synthesis, the magnitude of the positive rate change was shown to be proportional to the relative increase in DNA in the previous cell cycle. Collectively, these data support the idea that expression of newly replicated genes of this enzyme can be delayed into the subsequent cell cycle in cells in the continuous presence of inducer. Studies with cycloheximide indicated that the inducible GDH and another GDH isozyme were stable in fully induced cells in the absence of protein synthesis. However, after ammonium was removed from the culture medium, the activity of the inducible GDH decreased rapidly in vivo, with a half-time of 5 to 10 min at 38.5 degrees C, whereas the rate of accumulation of the other GDH isozyme did not change. Addition of cycloheximide, at the time of inducer removal, prevented this loss in activity of the inducible GDH. The inability to rescue the activity of the inducible GDH, by readdition of ammonium during the deinduction period, indicates that this enzyme probably underwent irreversible inactivation and/or proteolytic degradation. PMID:45486

  3. Biofilm growth of Chlorella sorokiniana in a rotating biological contactor based photobioreactor.

    PubMed

    Blanken, W; Janssen, M; Cuaresma, M; Libor, Z; Bhaiji, T; Wijffels, R H

    2014-12-01

    Microalgae biofilms could be used as a production platform for microalgae biomass. In this study, a photobioreactor design based on a rotating biological contactor (RBC) was used as a production platform for microalgae biomass cultivated in biofilm. In the photobioreactor, referred to as Algadisk, microalgae grow in biofilm on vertical rotating disks partially submerged in a growth medium. The objective is to evaluate the potential of the Algadisk photobioreactor with respect to the effects of disk roughness, disk rotation speed and CO2 concentration. These objectives where evaluated in relationship to productivity, photosynthetic efficiency, and long-term cultivation stability in a lab-scale Algadisk system. Although the lab-scale Algadisk system is used, operation parameters evaluated are relevant for scale-up. Chlorella Sorokiniana was used as model microalgae. In the lab-scale Algadisk reactor, productivity of 20.1 ± 0.7 g per m(2) disk surface per day and a biomass yield on light of 0.9 ± 0.04 g dry weight biomass per mol photons were obtained. Different disk rotation speeds did demonstrate minimal effects on biofilm growth and on the diffusion of substrate into the biofilm. CO2 limitation, however, drastically reduced productivity to 2-4 g per m(2) disk surface per day. Productivity could be maintained over a period of 21 weeks without re-inoculation of the Algadisk. Productivity decreased under extreme conditions such as pH 9-10, temperature above 40°C, and with low CO2 concentrations. Maximal productivity, however, was promptly recovered when optimal cultivation conditions were reinstated. These results exhibit an apparent opportunity to employ the Algadisk photobioreactor at large scale for microalgae biomass production if diffusion does not limit the CO2 supply.

  4. Biogenic hydrogen and methane production from Chlorella vulgaris and Dunaliella tertiolecta biomass

    PubMed Central

    2011-01-01

    Background Microalgae are a promising feedstock for biofuel and bioenergy production due to their high photosynthetic efficiencies, high growth rates and no need for external organic carbon supply. In this study, utilization of Chlorella vulgaris (a fresh water microalga) and Dunaliella tertiolecta (a marine microalga) biomass was tested as a feedstock for anaerobic H2 and CH4 production. Results Anaerobic serum bottle assays were conducted at 37°C with enrichment cultures derived from municipal anaerobic digester sludge. Low levels of H2 were produced by anaerobic enrichment cultures, but H2 was subsequently consumed even in the presence of 2-bromoethanesulfonic acid, an inhibitor of methanogens. Without inoculation, algal biomass still produced H2 due to the activities of satellite bacteria associated with algal cultures. CH4 was produced from both types of biomass with anaerobic enrichments. Polymerase chain reaction-denaturing gradient gel electrophoresis profiling indicated the presence of H2-producing and H2-consuming bacteria in the anaerobic enrichment cultures and the presence of H2-producing bacteria among the satellite bacteria in both sources of algal biomass. Conclusions H2 production by the satellite bacteria was comparable from D. tertiolecta (12.6 ml H2/g volatile solids (VS)) and from C. vulgaris (10.8 ml H2/g VS), whereas CH4 production was significantly higher from C. vulgaris (286 ml/g VS) than from D. tertiolecta (24 ml/g VS). The high salinity of the D. tertiolecta slurry, prohibitive to methanogens, was the probable reason for lower CH4 production. PMID:21943287

  5. Quantitative proteomic profiling reveals photosynthesis responsible for inoculum size dependent variation in Chlorella sorokiniana.

    PubMed

    Ma, Qian; Wang, Jiangxin; Lu, Shuhuan; Lv, Yajin; Yuan, Yingjin

    2013-03-01

    High density cultivation is essential to industrial production of biodiesel from microalgae, which involves in variations of micro-environment around individual cells, including light intensity, nutrition distribution, other abiotic stress and so on. To figure out the main limit factor in high inoculum cultivation, a quantitative proteomic analysis (iTRAQ-on-line 2-D nano-LC/MS) in a non-model green microalga, Chlorella sorokiniana, under different inoculum sizes was conducted. The resulting high-quality proteomic dataset consisted of 695 proteins. Using a cutoff of P < 0.05, 241 unique proteins with differential expression levels were identified between control and different inoculum sizes. Functional analysis showed that proteins participating in photosynthesis (light reaction) and Calvin cycle (carbon reaction pathway) had highest expression levels under inoculum size of 1 × 10(6) cells mL(-1), and lowest levels under 1 × 10(7) cells mL(-1). Canonical correlation analysis of the photosynthesis related proteins and metabolites biomarkers showed that a good correlation existed between them (canonical coefficient was 0.987), suggesting photosynthesis process greatly affected microalgae biodiesel productivity and quality. Proteomic study of C. sorokiniana under different illuminations was also conducted to confirm light intensity as a potential limit factor of high inoculum size. Nearly two thirds of proteins showed up-regulation under the illumination of 70-110 µmol m(-2) s(-1), compared to those of 40 µmol m(-2) s(-1). This result suggested that by elegantly adjusting light conditions, high cell density cultivation and high biodiesel production might be achieved.

  6. Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis.

    PubMed

    Zhou, Qiongzhi; Li, Feng; Ge, Fei; Liu, Na; Kuang, Yangduo

    2016-10-01

    Toxicants are generally harmful to biotechnology in wastewater treatment. However, trace toxicant can induce microbial hormesis, but to date, it is still unknown how this phenomenon affects nutrient removal during municipal wastewater treatment process. Therefore, this study focused on the effects of hormesis induced by cetyltrimethyl ammonium bromide (CTAB), a representative quaternary ammonium cationic surfactant, on nutrient removal by Chlorella vulgaris F1068. Results showed that when the concentration of CTAB was less than 10 ng/L, the cellular components chlorophyll a, proteins, polysaccharides, and total lipids increased by 10.11, 58.17, 38.78, and 11.87 %, respectively, and some enzymes in nutrient metabolism of algal cells, such as glutamine synthetase (GS), acid phosphatase (ACP), H(+)-ATPase, and esterase, were also enhanced. As a result, the removal efficiencies of ammonia nitrogen (NH4 (+)) and total phosphorus (TP) increased by 14.66 and 8.51 %, respectively, compared to the control during a 7-day test period. The underlying mechanism was mainly due to an enhanced photosynthetic activity of C. vulgaris F1068 indicated by the increase in chlorophyll fluorescence parameters (the value of Fv/Fm, ΦII, Fv/Fo, and rETR increased by 12.99, 7.56, 25.59, and 8.11 %, respectively) and adenylate energy charge (AEC) (from 0.68 to 0.72). These results suggest that hormesis induced by trace toxicants could enhance the nutrient removal, which would be further considered in the design of municipal wastewater treatment processes. Graphical abstract The schematic mechanism of C. vulgaris F1068 under CTAB induced hormesis. Green arrows ( ) represent the increase and the red arrow ( ) represents the decrease. PMID:27381355

  7. Phytochelatin induction by selenate in Chlorella vulgaris, and regulation of effect by sulfate levels.

    PubMed

    Simmons, Denina B D; Emery, R J Neil

    2011-02-01

    Phytochelatins (PCs) are short metal detoxification peptides made from the sulfur-rich molecule glutathione. The production of PCs by algae caused by Se exposure has never been studied, although many algae accumulate Se, forming Se-rich proteins and peptides, and higher plants have demonstrated PC production when treated with Se; therefore, a goal of the current study was to examine whether Se induces PC production in algae. Furthermore, selenate is thought to compete with sulfate in the S assimilation pathway, and sulfate therefore may have a protective effect against the toxic effects of high doses of Se in algae. Hence, the interaction of selenate and sulfate was investigated with respect to the induction of PCs. Chlorella vulgaris was cultured in media with either low (31.2 µM) or high (312 µM) concentrations of sulfate. These cultures were exposed to selenate in doses of 7, 35, and 70 nM for 48 h. In a separate treatment, Cd (890 nM) was added as a positive PC-inducing control, and one no-metal negative control was used. Total Se and Se speciation were determined, and glutathione, phytochelatin-2, and phytochelatin-3 were quantified in each of cell digests, cell medium, and cell lysates. We found that PCs and their precursor glutathione were induced by selenate as well as by a Cd control. The high concentration of sulfate was able to counter selenate-induced production of PCs and glutathione. These data support two possible mechanisms: a negative feedback system in the S assimilation pathway that affects PC production when sulfate is abundant, and competition for uptake at the ion transport level between selenate and sulfate.

  8. Inhibitory effects of atrazine on Chlorella vulgaris as assessed by real-time polymerase chain reaction.

    PubMed

    Qian, Haifeng; Daniel Sheng, G; Liu, Weiping; Lu, Yingcong; Liu, Zhenghai; Fu, Zhengwei

    2008-01-01

    Atrazine, a highly toxic herbicide, is frequently detected in surface water because of its heavy application. Algae are among the aquatic organisms most susceptible to atrazine pollution in water. In the present study, the aquatic alga Chlorella vulgaris Beijerinck was chosen to assess the acute toxicity of atrazine (48-96 h) in terms of gene transcription and physiological changes. A real-time polymerase chain reaction (PCR) assay was used to quantify transcript levels of three photosystem genes in C. vulgaris. The diel patterns for regulation of the psaB (photosystem I reaction center protein subunit B), psbC (an integral membrane protein component of photosystem II), and rbcL (large subunit of ribulose-1,5-bisphosphate carboxylase oxygenase) gene transcripts were successfully quantified. Results showed that atrazine reduced the transcript abundances of three target genes and that the abundances decreased with increasing atrazine concentration. The determined smallest transcript levels of psaB, psbC, and rbcL, which occurred at the highest atrazine concentration tested (400 mug/L), were only 34.6, 34.6, and 8.1%, respectively, of the control sample value. Exposure to atrazine increased the level of malondialdehyde by 1.74-fold (the highest value) in C. vulgaris, suggesting potential oxidative damage to the alga. The activities of antioxidation enzymes (e.g., superoxide dismutase, peroxidase, and catalase) also increased markedly in the presence of atrazine, with maximum increases of 1.82-, 1.59-, and 2.31-fold, respectively. These elevated activities may help to alleviate the oxidative damage. Our results demonstrate that atrazine is highly toxic to this alga and that real-time PCR is an efficient technique for assessing the toxicity of xenobiotic compounds in algae.

  9. Glycerolipid synthesis in Chlorella kessleri 11h. I. Existence of a eukaryotic pathway.

    PubMed

    Sato, Norihiro; Tsuzuki, Mikio; Kawaguchi, Akihiko

    2003-07-01

    The fatty acid distributions at the sn-1 and sn-2 positions in major chloroplast lipids of Chlorella kessleri 11h, monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG), were determined to show the coexistence of both C16 and C18 acids at the sn-2 position, i.e. of prokaryotic and eukaryotic types in these galactolipids. For investigation of the biosynthetic pathway for glycerolipids in C. kessleri 11h, cells were fed with [14C]acetate for 30 min, and then the distribution of the radioactivity among glycerolipids and their constituent fatty acids during the subsequent chase period was determined. MGDG and DGDG were labeled predominantly as the sn-1-C18-sn-2-C16 (C18/C16) species as early as by the start of the chase, which suggested the synthesis of these lipids within chloroplasts via a prokaryotic pathway. On the other hand, the sn-1-C18-sn-2-C18 (C18/C18) species of these galactolipids gradually gained radioactivity at later times, concomitant with a decrease in the radioactivity of the C18/C18 species of phosphatidylcholine (PC). The change at later times can be explained by the conversion of the C18/C18 species of PC into galactolipids through a eukaryotic pathway. The results showed that C. kessleri 11h, distinct from most of other green algal species that were postulated mainly to use a prokaryotic pathway for the synthesis of chloroplast lipids, is similar to a group of higher plants designated as 16:3 plants in terms of the cooperation of prokaryotic and eukaryotic pathways to synthesize chloroplast lipids. We propose that the physiological function of the eukaryotic pathway in C. kessleri 11h is to supply chloroplast membranes with 18:3/18:3-MGDG for their functioning, and that the acquisition of a eukaryotic pathway by green algae was favorable for evolution into land plants.

  10. Cultivation of green algae Chlorella sp. in different wastewaters from municipal wastewater treatment plant.

    PubMed

    Wang, Liang; Min, Min; Li, Yecong; Chen, Paul; Chen, Yifeng; Liu, Yuhuan; Wang, Yingkuan; Ruan, Roger

    2010-10-01

    The objective of this study was to evaluate the growth of green algae Chlorella sp. on wastewaters sampled from four different points of the treatment process flow of a local municipal wastewater treatment plant (MWTP) and how well the algal growth removed nitrogen, phosphorus, chemical oxygen demand (COD), and metal ions from the wastewaters. The four wastewaters were wastewater before primary settling (#1 wastewater), wastewater after primary settling (#2 wastewater), wastewater after activated sludge tank (#3 wastewater), and centrate (#4 wastewater), which is the wastewater generated in sludge centrifuge. The average specific growth rates in the exponential period were 0.412, 0.429, 0.343, and 0.948 day(-1) for wastewaters #1, #2, #3, and #4, respectively. The removal rates of NH4-N were 82.4%, 74.7%, and 78.3% for wastewaters #1, #2, and #4, respectively. For #3 wastewater, 62.5% of NO3-N, the major inorganic nitrogen form, was removed with 6.3-fold of NO2-N generated. From wastewaters #1, #2, and #4, 83.2%, 90.6%, and 85.6% phosphorus and 50.9%, 56.5%, and 83.0% COD were removed, respectively. Only 4.7% was removed in #3 wastewater and the COD in #3 wastewater increased slightly after algal growth, probably due to the excretion of small photosynthetic organic molecules by algae. Metal ions, especially Al, Ca, Fe, Mg, and Mn in centrate, were found to be removed very efficiently. The results of this study suggest that growing algae in nutrient-rich centrate offers a new option of applying algal process in MWTP to manage the nutrient load for the aeration tank to which the centrate is returned, serving the dual roles of nutrient reduction and valuable biofuel feedstock production.

  11. Optimization of outdoor cultivation in flat panel airlift reactors for lipid production by Chlorella vulgaris.

    PubMed

    Münkel, Ronja; Schmid-Staiger, Ulrike; Werner, Achim; Hirth, Thomas

    2013-11-01

    Microalgae are discussed as a potential renewable feedstock for biofuel production. The production of highly concentrated algae biomass with a high fatty acid content, accompanied by high productivity with the use of natural sunlight is therefore of great interest. In the current study an outdoor pilot plant with five 30 L Flat Panel Airlift reactors (FPA) installed southwards were operated in 2011 in Stuttgart, Germany. The patented FPA reactor works on the basis of an airlift loop reactor and offers efficient intermixing for homogeneous light distribution. A lipid production process with the microalgae Chlorella vulgaris (SAG 211-12), under nitrogen and phosphorous deprivation, was established and evaluated in regard to the fatty acid content, fatty acid productivity and light yield. In the first set of experiments limitations caused by restricted CO₂ availability were excluded by enriching the media with NaOH. The higher alkalinity allows a higher CO₂ content of supplied air and leads to doubling of fatty acid productivity. The second set of experiments focused on how the ratio of light intensity to biomass concentration in the reactor impacts fatty acid content, productivity and light yield. The specific light availability was specified as mol photons on the reactor surface per gram biomass in the reactor. This is the first publication based on experimental data showing the quantitative correlation between specific light availability, fatty acid content and biomass light yield for a lipid production process under nutrient deprivation and outdoor conditions. High specific light availability leads to high fatty acid contents. Lower specific light availability increases fatty acid productivity and biomass light yield. An average fatty acid productivity of 0.39 g L⁻¹  day⁻¹ for a 12 days batch process with a final fatty acid content of 44.6% [w/w] was achieved. Light yield of 0.4 g mol photons⁻¹ was obtained for the first 6 days of

  12. Long-term outdoor cultivation by perfusing spent medium for biodiesel production from Chlorella minutissima.

    PubMed

    Oh, Sung Ho; Kwon, Min Chul; Choi, Woon Yong; Seo, Yong Chang; Kim, Ga Bin; Kang, Do Hyung; Lee, Shin Young; Lee, Hyeon Yong

    2010-08-01

    A unique perfusion process was developed to maintain high concentrations of marine alga, Chlorella minutissima. This method is based on recycling cells by continuous feeding with warm spent sea water from nuclear power plants, which has very similar properties as sea water. A temperature of at least 30 degrees C in a 200 L photo-bioreactor was maintained in this system by perfusion of the thermal plume for 80 days in the coldest season. The maximum cell concentration and total lipid content was 8.3 g-dry wt./L and 23.2 %, w/w, respectively, under mixotrophic conditions. Lipid production was found to be due to a partially or non-growth related process, which implies that large amounts of biomass are needed for a high accumulation of lipids within the cells. At perfusion rates greater than 1.5 L/h, the temperature of the medium inside the reactor was around 30 degrees C, which was optimal for cell growth. For this system, a perfusion rate of 2.8 L/h was determined to be optimal for maintaining rapid cell growth and lipid production during outdoor cultivation. It was absolutely necessary to maintain the appropriate perfusion rate so that the medium temperature was optimal for cell growth. In addition, the lipids produced using this process were shown to be feasible for biodiesel production since the lipid composition of C. minutissima grown under these conditions consisted of 17 % (w/w) of C(16) and 47% (w/w) of C(18). The combined results of this study clearly demonstrated that the discharged energy of the thermal plume could be reused to cultivate marine alga by maintaining a relatively constant temperature in an outdoor photo-bioreactor without the need for supplying any extra energy, which could allow for cheap production of biodiesel from waste energy.

  13. Cyanobacterium Microcystis aeruginosa response to pentachlorophenol and comparison with that of the microalga Chlorella vulgaris.

    PubMed

    de Morais, Paulo; Stoichev, Teodor; Basto, M Clara P; Ramos, V; Vasconcelos, V M; Vasconcelos, M Teresa S D

    2014-04-01

    Pentachlorophenol (PCP) effects on a strain of the cyanobacterium Microcystis aeruginosa were investigated at laboratory scale. This is the first systematic ecotoxicity study of the effects of PCP on an aquatic cyanobacterium. The microalga Chlorella vulgaris was studied in the same conditions as the cyanobacterium, in order to compare the PCP toxicity and its removal by the species. The cells were exposed to environmental levels of PCP during 10 days, in Fraquil culture medium, at nominal concentrations from 0.01 to 1000 μg L(-1), to the cyanobacterium, and 0.01 to 5000 μg L(-1), to the microalga. Growth was assessed by area under growth curve (AUC, optical density vs time) and chlorophyll a content (chla). The toxicity profiles of the two species were very different. The calculated effective concentrations EC20 and EC50 were much lower to M. aeruginosa, and its growth inhibition expressed by chla was concentration-dependent while by AUC was not concentration-dependent. The cells might continue to divide even with lower levels of chla. The number of C. vulgaris cells decreased with the PCP concentration without major impact on the chla. The effect of PCP on M. aeruginosa is hormetic: every concentration studied was toxic except 1 μg L(-1), which promoted its growth. The legal limit of PCP set by the European Union for surface waters (1 μg L(-1)) should be reconsidered since a toxic cyanobacteria bloom might occur. The study of the removal of PCP from the culture medium by the two species is an additional novelty of this work. M. aeruginosa could remove part of the PCP from the medium, at concentrations where toxic effects were observed, while C. vulgaris stabilized it. PMID:24462928

  14. Pentachlorophenol toxicity to a mixture of Microcystis aeruginosa and Chlorella vulgaris cultures.

    PubMed

    de Morais, Paulo; Stoichev, Teodor; Basto, M Clara P; Ramos, V; Vasconcelos, V M; Vasconcelos, M Teresa S D

    2014-05-01

    Pentachlorophenol (PCP) is a priority pollutant due to its persistence and high toxicity. For the first time, PCP effects were investigated at laboratory scale on co-cultures of two ubiquitous freshwater phytoplankton species: the cyanobacterium Microcystis aeruginosa and the microalgae Chlorella vulgaris. The cells were exposed to environmental levels of PCP for 10 days in Fraquil culture medium, at nominal concentrations from 0.1 to 10,000 μg L(-1). Growth was assessed by area under growth curve (cell count vs. time). The phytoplankton community structure can be changed as a consequence of a PCP contamination. Low μg L(-1) levels of PCP are advantageous to M. aeruginosa. This is the first report of the promoting effect of PCP on the growth of aquatic cyanobacteria, using mixtures with microalgae. As a result of the direct toxic effects of high PCP concentrations on M. aeruginosa, C. vulgaris cell count increased given that in biological controls M. aeruginosa inhibited the C. vulgaris growth. At 16.7 mg L(-1), PCP already had direct toxic effects also on the microalga. The pH of culture medium tended to decrease with increasing PCP concentrations, which was mostly related to the growth inhibition of cyanobacterium caused by PCP. The PCP concentration was stable in the co-cultures, which differed from what has been observed in monocultures of the same two species. Short-term laboratory assays with two phytoplankton species gives important information on the species interactions, namely possible direct and indirect effects of a toxicant, and must be considered in ecotoxicity studies regarding environmental extrapolations. PMID:24681699

  15. Modelling and Optimization of Nannochloropsis and Chlorella Growth for Various Locations and Seasons

    NASA Astrophysics Data System (ADS)

    Gharagozloo, P. E.

    2014-12-01

    Efficient production of algal biofuels could reduce dependence on foreign oil providing domestic renewable energy. Algae-based biofuels are attractive for their large oil yield potential despite decreased land use and natural-resource requirements compared to terrestrial energy crops. Important factors controlling algal-lipid productivity include temperature, nutrient availability, salinity, pH, and the light-to-biomass conversion rate. Computational approaches allow for inexpensive predictions of algae-growth kinetics for various bioreactor sizes and geometries without multiple, expensive measurement systems. In this work, we parameterize our physics-based computational algae growth model for the marine Nannochloropsis oceanica and freshwater Chlorella species. We then compare modelling results with experiments conducted in identical raceway ponds at six geographical locations in the United States (Hawaii, California, Arizona, Ohio, Georgia, and Florida) and three seasons through the Algae Testbed Public Private Partnership - Unified Field Studies. Results show that the computational model effectively predicts algae growth in systems across varying environments and identifies the causes for reductions in algal productivities. The model is then used to identify improvements to the cultivation system to produce higher biomass yields. This model could be used to study the effects of scale-up including the effects of predation, depth-decay of light (light extinction), and optimized nutrient and CO2 delivery. As more multifactorial data are accumulated for a variety of algal strains, the model could be used to select appropriate algal species for various geographic and climatic locations and seasons. Applying the model facilitates optimization of pond designs based on location and season.

  16. Chlorella vulgaris Attenuates Dermatophagoides Farinae-Induced Atopic Dermatitis-Like Symptoms in NC/Nga Mice.

    PubMed

    Kang, Heerim; Lee, Chang Hyung; Kim, Jong Rhan; Kwon, Jung Yeon; Seo, Sang Gwon; Han, Jae Gab; Kim, Byung Gon; Kim, Jong-Eun; Lee, Ki Won

    2015-01-01

    Atopic dermatitis (AD) is a chronic and inflammatory skin disease that can place a significant burden on quality of life for patients. AD most frequently appears under the age of six and although its prevalence is increasing worldwide, therapeutic treatment options are limited. Chlorella vulgaris (CV) is a species of the freshwater green algae genus chlorella, and has been reported to modulate allergy-inducible factors when ingested. Here, we examined the effect of CV supplementation on AD-like symptoms in NC/Nga mice. CV was orally administrated for six weeks while AD-like symptoms were induced via topical application of Dermatophagoides farinae extract (DFE). CV treatment reduced dermatitis scores, epidermal thickness, and skin hydration. Histological analysis also revealed that CV treatment reduced DFE-induced eosinophil and mast cell infiltration into the skin, while analysis of serum chemokine levels indicated that CV treatment downregulated thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) levels. In addition, CV treatment downregulated mRNA expression levels of IL-4 and IFN-γ. Taken together, these results suggest that CV extract may have potential as a nutraceutical ingredient for the prevention of AD. PMID:26404252

  17. Chlorella vulgaris Attenuates Dermatophagoides Farinae-Induced Atopic Dermatitis-Like Symptoms in NC/Nga Mice

    PubMed Central

    Kang, Heerim; Lee, Chang Hyung; Kim, Jong Rhan; Kwon, Jung Yeon; Seo, Sang Gwon; Han, Jae Gab; Kim, Byung Gon; Kim, Jong-Eun; Lee, Ki Won

    2015-01-01

    Atopic dermatitis (AD) is a chronic and inflammatory skin disease that can place a significant burden on quality of life for patients. AD most frequently appears under the age of six and although its prevalence is increasing worldwide, therapeutic treatment options are limited. Chlorella vulgaris (CV) is a species of the freshwater green algae genus chlorella, and has been reported to modulate allergy-inducible factors when ingested. Here, we examined the effect of CV supplementation on AD-like symptoms in NC/Nga mice. CV was orally administrated for six weeks while AD-like symptoms were induced via topical application of Dermatophagoides farinae extract (DFE). CV treatment reduced dermatitis scores, epidermal thickness, and skin hydration. Histological analysis also revealed that CV treatment reduced DFE-induced eosinophil and mast cell infiltration into the skin, while analysis of serum chemokine levels indicated that CV treatment downregulated thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) levels. In addition, CV treatment downregulated mRNA expression levels of IL-4 and IFN-γ. Taken together, these results suggest that CV extract may have potential as a nutraceutical ingredient for the prevention of AD. PMID:26404252

  18. Simultaneous production of triacylglycerol and high-value carotenoids by the astaxanthin-producing oleaginous green microalga Chlorella zofingiensis.

    PubMed

    Liu, Jin; Mao, Xuemei; Zhou, Wenguang; Guarnieri, Michael T

    2016-08-01

    The production of lipids and astaxanthin, a high-value carotenoid, by Chlorella zofingiensis was investigated under different culture conditions. Comparative analysis revealed a good correlation between triacylglycerol (TAG) and astaxanthin accumulation in C. zofingiensis. Stress conditions promoted cell size and weight and induced the accumulation of neutral lipids, especially TAG and astaxanthin, with a concomitant decrease in membrane lipids. The highest contents of TAG and astaxanthin achieved were 387 and 4.89mgg(-1) dry weight, respectively. A semi-continuous culture strategy was developed to optimize the TAG and astaxanthin productivities, which reached 297 and 3.3mgL(-1)day(-1), respectively. Additionally, astaxanthin accumulation was enhanced by inhibiting de novo fatty acid biosynthesis. In summary, our study represents a pioneering work of utilizing Chlorella for the integrated production of lipids and high-value products and C. zofingiensis has great potential to be a promising production strain and serve as an emerging oleaginous model alga. PMID:27152772

  19. Assessment of a tannin-based organic polymer to harvest Chlorella vulgaris biomass from swine wastewater digestate phycoremediation.

    PubMed

    Mezzari, M P; da Silva, M L B; Pirolli, M; Perazzoli, S; Steinmetz, R L R; Nunes, E O; Soares, H M

    2014-01-01

    This study investigated the efficiency of an organic tannin polymer alone or amended with polyacrylamide to harvest Chlorella vulgaris biomass grown in a laboratory-scale photobioreactor treating swine wastewater digestate. The effect of biomass concentration, tannin (TAN) dosages and changes in pH were evaluated in jar test experiments. Among the TAN concentrations tested (11, 22, 44, 89, 178 mg L(-1)), 11 mg L(-1) showed the highest biomass recovery (97%). The highest coagulation/ flocculation efficiencies were obtained at pH 5 to 7. Flocculation efficiency improved from 50 to 97% concomitant with the increasing biomass concentrations from 45 to 165 mg L(-1), respectively. Recovery efficiencies above 95% were achieved with the same TAN dosage (11 mg L(-1)) irrespective of the concentration of organic carbon present (75 to 300 mg TOC L(-1)). Overall, the results suggest that TAN could become an interesting alternative choice of non-toxic organic polymer for harvesting Chlorella sp. from organic-rich wastewater. PMID:25225937

  20. Enhanced mixotrophic growth of microalga Chlorella sp. on pretreated swine manure for simultaneous biofuel feedstock production and nutrient removal.

    PubMed

    Hu, Bing; Min, Min; Zhou, Wenguang; Du, Zhenyi; Mohr, Michael; Chen, Paul; Zhu, Jun; Cheng, Yanling; Liu, Yuhuan; Ruan, Roger

    2012-12-01

    The objectives were to assess the feasibility of using fermented liquid swine manure (LSM) as nutrient supplement for cultivation of Chlorella sp. UMN271, a locally isolated facultative heterotrophic strain, and to evaluate the nutrient removal efficiencies by alga compared with those from the conventionally decomposed LSM-algae system. The results showed that addition of 0.1% (v/v) acetic, propionic and butyric acids, respectively, could promote algal growth, enhance nutrient removal efficiencies and improve total lipids productivities during a 7-day batch cultivation. Similar results were observed when the acidogenic fermentation was applied to the sterilized and raw digested LSM rich in volatile fatty acids (VFAs). High algal growth rate (0.90 d(-1)) and fatty acid content (10.93% of the dry weight) were observed for the raw VFA-enriched manure sample. Finally, the fatty acid profile analyses showed that Chlorella sp. grown on acidogenically digested manure could be used as a feedstock for high-quality biodiesel production. PMID:23073091

  1. Characterization of biosynthesized gold nanoparticles from aqueous extract of Chlorella vulgaris and their anti-pathogenic properties

    NASA Astrophysics Data System (ADS)

    Annamalai, Jayshree; Nallamuthu, Thangaraju

    2015-06-01

    In this study, biosynthesis of self-assembled gold nanoparticles (GNPs) was accomplished using an aqueous extract of green microalga, Chlorella vulgaris. The optical, physical, chemical and bactericidal properties of the GNPs were investigated to identify their average shape and size, crystal nature, surface chemistry and toxicity, via UV-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and antimicrobial activity. The sizes of the spherical self-assembled cores of the synthesized GNPs ranged from 2 to 10 nm. The XRD patterns showed a (111) preferential orientation and the crystalline nature of the GNPs. The results of the FTIR analysis suggested that the peptides, proteins, phenol and flavonoid carried out the dual function of effective Au III reduction and successful capping of the GNPs. Human pathogen Candida albicans and Staphylococcus aureus were susceptible to synthesized aqueous GNPs. Thus, biosynthesis, stabilization and self-assembly of the GNPs by Chlorella vulgaris extract can be an example of green chemistry and effective drug in the medicinal field.

  2. Characterization of biosynthesized gold nanoparticles from aqueous extract of Chlorella vulgaris and their anti-pathogenic properties

    NASA Astrophysics Data System (ADS)

    Annamalai, Jayshree; Nallamuthu, Thangaraju

    2014-09-01

    In this study, biosynthesis of self-assembled gold nanoparticles (GNPs) was accomplished using an aqueous extract of green microalga, Chlorella vulgaris. The optical, physical, chemical and bactericidal properties of the GNPs were investigated to identify their average shape and size, crystal nature, surface chemistry and toxicity, via UV-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and antimicrobial activity. The sizes of the spherical self-assembled cores of the synthesized GNPs ranged from 2 to 10 nm. The XRD patterns showed a (111) preferential orientation and the crystalline nature of the GNPs. The results of the FTIR analysis suggested that the peptides, proteins, phenol and flavonoid carried out the dual function of effective Au III reduction and successful capping of the GNPs. Human pathogen Candida albicans and Staphylococcus aureus were susceptible to synthesized aqueous GNPs. Thus, biosynthesis, stabilization and self-assembly of the GNPs by Chlorella vulgaris extract can be an example of green chemistry and effective drug in the medicinal field.

  3. Organic and Inorganic Nitrogen Impact Chlorella variabilis Productivity and Host Quality for Viral Production and Cell Lysis.

    PubMed

    Cheng, Yu-Shen; Labavitch, John; VanderGheynst, Jean S

    2015-05-01

    Microalgae have been proposed as a potential feedstock for biofuel production; however, cell disruption is usually required for collection and utilization of cytoplasmic polysaccharides and lipids. Virus infection might be one approach to disrupt the cell wall. The concentration of yeast extract and presence of KNO3 in algae cultivation media were investigated to observe their effects on Chlorella variabilis NC64A physiology and composition and the subsequent effect on production of Chlorella virus and disruption of infected cells. Cytoplasmic starch accumulation increased from 5% to approximately 35% of the total dry weight when yeast extract decreased from 1 to 0.25 g L(-1). When cells were cultured with the lowest nitrogen levels, the total polysaccharide accounted for more than 50% of the cell wall, which was 1.7 times higher than the content in cells cultured with the highest nitrogen levels. The C/N ratio of the algal biomass decreased by a factor of approximately 2 when yeast extract increased from 0.25 to 1 g L(-1). After virus infection, cells with a low C/N ratio produced a 7.6 times higher burst size than cells with a high C/N ratio, suggesting that the nitrogen content in C. variabilis has a large influence on viral production and cell lysis. The results have implications on management of nitrogen for both the synthesis of products from algae and product recovery via viral lysis.

  4. Cultivating Chlorella sp. in a pilot-scale photobioreactor using centrate wastewater for microalgae biomass production and wastewater nutrient removal.

    PubMed

    Min, Min; Wang, Liang; Li, Yecong; Mohr, Michael J; Hu, Bing; Zhou, Wenguang; Chen, Paul; Ruan, Roger

    2011-09-01

    This study is concerned with a novel mass microalgae production system which, for the first time, uses "centrate", a concentrated wastewater stream, to produce microalgal biomass for energy production. Centrate contains a high level of nutrients that support algal growth. The objective of this study was to investigate the growth characteristics of a locally isolated microalgae strain Chlorella sp. in centrate and its ability to remove nutrients from centrate. A pilot-scale photobioreactor (PBR) was constructed at a local wastewater treatment plant. The system was tested under different harvesting rates and exogenous CO(2) levels with the local strain of Chlorella sp. Under low light conditions (25 μmol·m(-2)s(-1)) the system can produce 34.6 and 17.7 g·m(-2)day(-1) biomass in terms of total suspended solids and volatile suspended solids, respectively. At a one fourth harvesting rate, reduction of chemical oxygen demand, total Kjeldahl nitrogen, and soluble total phosphorus were 70%, 61%, and 61%, respectively. The addition of CO(2) to the system did not exhibit a positive effect on biomass productivity or nutrient removal in centrate which is an organic carbon rich medium. The unique PBR system is highly scalable and provides a great opportunity for biomass production coupled with wastewater treatment. PMID:21494756

  5. Selenium Accumulation in Unicellular Green Alga Chlorella vulgaris and Its Effects on Antioxidant Enzymes and Content of Photosynthetic Pigments

    PubMed Central

    Sun, Xian; Zhong, Yu; Huang, Zhi; Yang, Yufeng

    2014-01-01

    The aim of the present study was to investigate selenite effects in the unicellular green algae Chlorella vulgaris as a primary producer and the relationship with intracellular bioaccumulation. The effects of selenite were evaluated by measuring the effect of different selenite concentrations on algal growth during a 144 h exposure period. It was found that lower Se concentrations (≤75 mg L−1) positively promoted C. vulgaris growth and acted as antioxidant by inhibiting lipid peroxidation (LPO) and intracellular reactive oxygen species (ROS). The antioxidative effect was associated with an increase in guaiacol peroxidase (GPX), catalase (CAT), superoxide dismutase (SOD) and photosynthetic pigments. Meanwhile, significant increase in the cell growth rate and organic Se content was also detected in the algae. In contrast, these changes were opposite in C. vulgaris exposed to Se higher than 100 mg L−1. The antioxidation and toxicity appeared to be correlated to Se bioaccumulation, which suggests the appropriate concentration of Se in the media accumulation of C. vulgaris should be 75 mg L−1. Taken together, C. vulgaris possesses tolerance to Se, and Se-Chlorella could be developed as antioxidative food for aquaculture and human health. PMID:25375113

  6. Organic and Inorganic Nitrogen Impact Chlorella variabilis Productivity and Host Quality for Viral Production and Cell Lysis.

    PubMed

    Cheng, Yu-Shen; Labavitch, John; VanderGheynst, Jean S

    2015-05-01

    Microalgae have been proposed as a potential feedstock for biofuel production; however, cell disruption is usually required for collection and utilization of cytoplasmic polysaccharides and lipids. Virus infection might be one approach to disrupt the cell wall. The concentration of yeast extract and presence of KNO3 in algae cultivation media were investigated to observe their effects on Chlorella variabilis NC64A physiology and composition and the subsequent effect on production of Chlorella virus and disruption of infected cells. Cytoplasmic starch accumulation increased from 5% to approximately 35% of the total dry weight when yeast extract decreased from 1 to 0.25 g L(-1). When cells were cultured with the lowest nitrogen levels, the total polysaccharide accounted for more than 50% of the cell wall, which was 1.7 times higher than the content in cells cultured with the highest nitrogen levels. The C/N ratio of the algal biomass decreased by a factor of approximately 2 when yeast extract increased from 0.25 to 1 g L(-1). After virus infection, cells with a low C/N ratio produced a 7.6 times higher burst size than cells with a high C/N ratio, suggesting that the nitrogen content in C. variabilis has a large influence on viral production and cell lysis. The results have implications on management of nitrogen for both the synthesis of products from algae and product recovery via viral lysis. PMID:25805020

  7. Stearoyl-acyl carrier protein desaturase gene from the oleaginous microalga Chlorella zofingiensis: cloning, characterization and transcriptional analysis.

    PubMed

    Liu, Jin; Sun, Zheng; Zhong, Yujuan; Huang, Junchao; Hu, Qiang; Chen, Feng

    2012-12-01

    The green alga Chlorella zofingiensis can accumulate high level of oleic acid (OA, C18:1△(9)) rich oils in response to stress conditions. To understand the regulation of biosynthesis of fatty acid in particular OA at the molecular level, we cloned and characterized the stearoyl acyl carrier protein (ACP) desaturase (SAD) responsible for OA formation through desaturation of stearic acid (C18:0) from C. zofingiensis. Southern blot indicated that the C. zofingiensis genome contained a single copy of SAD, from which the deduced amino acid sequence shared high identity to the corresponding homologs from other microalgae and higher plants. The desaturation activity of SAD was demonstrated in vitro using C18:0-ACP as a substrate. Stress conditions such as high light (HL), nitrogen deficiency (N(-)), or combination of HL and N(-) (HL + N(-)) drastically up-regulated the transcripts of biotin carboxylase (BC, a subunit of ACCase) and SAD, and therefore induced considerably the cellular accumulation of total fatty acids including OA. Glucose (50 mM) gave rise to the similar up-regulation of the two genes and induction of fatty acid accumulation. The accumulation of intracellular reactive oxygen species was found to be associated with the up-regulation of genes. This is the first report of characterization of Chlorella-derived SAD and the results may contribute to understanding of the mechanisms involved in fatty acid/lipid biosynthesis in microalgae. PMID:22855030

  8. Chlorella vulgaris Attenuates Dermatophagoides Farinae-Induced Atopic Dermatitis-Like Symptoms in NC/Nga Mice.

    PubMed

    Kang, Heerim; Lee, Chang Hyung; Kim, Jong Rhan; Kwon, Jung Yeon; Seo, Sang Gwon; Han, Jae Gab; Kim, Byung Gon; Kim, Jong-Eun; Lee, Ki Won

    2015-09-02

    Atopic dermatitis (AD) is a chronic and inflammatory skin disease that can place a significant burden on quality of life for patients. AD most frequently appears under the age of six and although its prevalence is increasing worldwide, therapeutic treatment options are limited. Chlorella vulgaris (CV) is a species of the freshwater green algae genus chlorella, and has been reported to modulate allergy-inducible factors when ingested. Here, we examined the effect of CV supplementation on AD-like symptoms in NC/Nga mice. CV was orally administrated for six weeks while AD-like symptoms were induced via topical application of Dermatophagoides farinae extract (DFE). CV treatment reduced dermatitis scores, epidermal thickness, and skin hydration. Histological analysis also revealed that CV treatment reduced DFE-induced eosinophil and mast cell infiltration into the skin, while analysis of serum chemokine levels indicated that CV treatment downregulated thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) levels. In addition, CV treatment downregulated mRNA expression levels of IL-4 and IFN-γ. Taken together, these results suggest that CV extract may have potential as a nutraceutical ingredient for the prevention of AD.

  9. Immobilization of Chlorella sorokiniana GXNN 01 in alginate for removal of N and P from synthetic wastewater.

    PubMed

    Liu, Kai; Li, Jian; Qiao, Hongjin; Lin, Apeng; Wang, Guangce

    2012-06-01

    High costs and issues such as a high cell concentrations in effluents are encountered when utilizing microalgae for wastewater treatment. The present study analyzed nitrogen and phosphate removal under autotrophic, heterotrophic, mixotrophic and micro-aerobic conditions by Chlorella sorokiniana GXNN 01 immobilized in calcium alginate. The immobilized cells grew as well as free-living cells under micro-aerobic conditions and better than free-living cells under the other conditions. The immobilized cells had a higher ammonium removal rate (21.84%, 43.59% and 41.46%) than free living cells (14.35%, 38.57% and 40.59%) under autotrophic, heterotrophic, and micro-aerobic conditions, and higher phosphate removal rate (87.49%, 88.65% and 84.84%) than free living cells (20.21%, 42.27% and 53.52%) under heterotrophic, mixotrophic and micro-aerobic conditions, respectively. The data indicate that immobilized Chlorella sorokiniana GXNN 01 is a suitable species for use in wastewater treatment.

  10. Combining and Comparing Coalescent, Distance and Character-Based Approaches for Barcoding Microalgaes: A Test with Chlorella-Like Species (Chlorophyta)

    PubMed Central

    Zou, Shanmei; Fei, Cong; Song, Jiameng; Bao, Yachao; He, Meilin; Wang, Changhai

    2016-01-01

    Several different barcoding methods of distinguishing species have been advanced, but which method is the best is still controversial. Chlorella is becoming particularly promising in the development of second-generation biofuels. However, the taxonomy of Chlorella–like organisms is easily confused. Here we report a comprehensive barcoding analysis of Chlorella-like species from Chlorella, Chloroidium, Dictyosphaerium and Actinastrum based on rbcL, ITS, tufA and 16S sequences to test the efficiency of traditional barcoding, GMYC, ABGD, PTP, P ID and character-based barcoding methods. First of all, the barcoding results gave new insights into the taxonomic assessment of Chlorella-like organisms studied, including the clear species discrimination and resolution of potentially cryptic species complexes in C. sorokiniana, D. ehrenbergianum and C. Vulgaris. The tufA proved to be the most efficient barcoding locus, which thus could be as potential “specific barcode” for Chlorella-like species. The 16S failed in discriminating most closely related species. The resolution of GMYC, PTP, P ID, ABGD and character-based barcoding methods were variable among rbcL, ITS and tufA genes. The best resolution for species differentiation appeared in tufA analysis where GMYC, PTP, ABGD and character-based approaches produced consistent groups while the PTP method over-split the taxa. The character analysis of rbcL, ITS and tufA sequences could clearly distinguish all taxonomic groups respectively, including the potentially cryptic lineages, with many character attributes. Thus, the character-based barcoding provides an attractive complement to coalescent and distance-based barcoding. Our study represents the test that proves the efficiency of multiple DNA barcoding in species discrimination of microalgaes. PMID:27092945

  11. Metallomics and NMR-based metabolomics of Chlorella sp. reveal the synergistic role of copper and cadmium in multi-metal toxicity and oxidative stress.

    PubMed

    Zhang, Wenlin; Tan, Nicole G J; Fu, Baohui; Li, Sam F Y

    2015-03-01

    Industrial wastewaters often contain high levels of metal mixtures, in which metal mixtures may have synergistic or antagonistic effects on aquatic organisms. A combination of metallomics and nuclear magnetic resonance spectroscopy (NMR)-based metabolomics was employed to understand the consequences of multi-metal systems (Cu, Cd, Pb) on freshwater microalgae. Morphological characterization, cell viability and chlorophyll a determination of metal-spiked Chlorella sp. suggested synergistic effects of Cu and Cd on growth inhibition and toxicity. While Pb has no apparent effect on Chlorella sp. metabolome, a substantial decrease of sucrose, amino acid content and glycerophospholipid precursors in Cu-spiked microalgae revealed Cu-induced oxidative stress. Addition of Cd to Cu-spiked cultures induced more drastic metabolic perturbations, hence we confirmed that Cu and Cd synergistically influenced photosynthesis inhibition, oxidative stress and membrane degradation. Total elemental analysis revealed a significant decrease in K, and an increase in Na, Mg, Zn and Mn concentrations in Cu-spiked cultures. This indicated that Cu is more toxic to Chlorella sp. as compared to Cd or Pb, and the combination of Cu and Cd has a strong synergistic effect on Chlorella sp. oxidative stress induction. Oxidative stress is confirmed by liquid chromatography tandem mass spectrometry analysis, which demonstrated a drastic decrease in the GSH/GSSG ratio solely in Cu-spiked cultures. Interestingly, we observed Cu-facilitated Cd and Pb bioconcentration in Chlorella sp. The absence of phytochelatins and an increment of extracellular polymeric substances (EPS) yields in Cu-spiked cultures suggested that the mode of bioconcentration of Cd and Pb is through adsorption of free metals onto the algal EPS rather than intracellular chelation to phytochelatins.

  12. Metallomics and NMR-based metabolomics of Chlorella sp. reveal the synergistic role of copper and cadmium in multi-metal toxicity and oxidative stress.

    PubMed

    Zhang, Wenlin; Tan, Nicole G J; Fu, Baohui; Li, Sam F Y

    2015-03-01

    Industrial wastewaters often contain high levels of metal mixtures, in which metal mixtures may have synergistic or antagonistic effects on aquatic organisms. A combination of metallomics and nuclear magnetic resonance spectroscopy (NMR)-based metabolomics was employed to understand the consequences of multi-metal systems (Cu, Cd, Pb) on freshwater microalgae. Morphological characterization, cell viability and chlorophyll a determination of metal-spiked Chlorella sp. suggested synergistic effects of Cu and Cd on growth inhibition and toxicity. While Pb has no apparent effect on Chlorella sp. metabolome, a substantial decrease of sucrose, amino acid content and glycerophospholipid precursors in Cu-spiked microalgae revealed Cu-induced oxidative stress. Addition of Cd to Cu-spiked cultures induced more drastic metabolic perturbations, hence we confirmed that Cu and Cd synergistically influenced photosynthesis inhibition, oxidative stress and membrane degradation. Total elemental analysis revealed a significant decrease in K, and an increase in Na, Mg, Zn and Mn concentrations in Cu-spiked cultures. This indicated that Cu is more toxic to Chlorella sp. as compared to Cd or Pb, and the combination of Cu and Cd has a strong synergistic effect on Chlorella sp. oxidative stress induction. Oxidative stress is confirmed by liquid chromatography tandem mass spectrometry analysis, which demonstrated a drastic decrease in the GSH/GSSG ratio solely in Cu-spiked cultures. Interestingly, we observed Cu-facilitated Cd and Pb bioconcentration in Chlorella sp. The absence of phytochelatins and an increment of extracellular polymeric substances (EPS) yields in Cu-spiked cultures suggested that the mode of bioconcentration of Cd and Pb is through adsorption of free metals onto the algal EPS rather than intracellular chelation to phytochelatins. PMID:25569820

  13. Protective effects of Chlorella vulgaris in lead-exposed mice infected with Listeria monocytogenes.

    PubMed

    Queiroz, Mary L S; Rodrigues, Ana P O; Bincoletto, Claudia; Figueirêdo, Camila A V; Malacrida, Solange

    2003-06-01

    Chlorella vulgaris extract (CVE) was examined for its chelating effects on the myelosuppression induced by lead in Listeria monocytogenes-infected mice. The reduction in the number of bone marrow granulocyte-macrophage progenitors (CFU-GM) observed after the infection was more severe in the groups previously exposed to lead. Extramedullar hematopoiesis, which was drastically increased after the infection, was not altered by the presence of lead. Treatment with CVE, given simultaneously or following lead exposure, restored to control values the myelosuppression observed in infected/lead-exposed mice and produced a significant increase in serum colony-stimulating activity. The benefits of the CVE treatment were also evident in the recovery of thymus weight, since the reduction produced by the infection was further potentiated by lead exposure. The efficacy of CVE was evident when infected and infected/lead-exposed mice were challenged with a lethal dose of L. monocytogenes after a 10-day treatment with 50 mg/kg CVE/day, given simultaneously to the exposure to 1300 ppm lead acetate in drinking water. Survival rates of 30% for the infected group and of 20% for the infected/lead-exposed groups were observed. Evidence that these protective effects of CVE are partly due to its chelating effect was given by the changes observed in blood lead levels. We have observed in the group receiving the CVE/lead simultaneous exposure a dramatic reduction of 66.03% in blood lead levels, when compared to lead-exposed nontreated control. On the other hand, CVE treatment following lead exposure produced a much less effective chelating effect. CVE treatments for 3 or 10 days, starting 24 h following lead exposure, produced a reduction in blood lead levels of 13.5% and 17%, respectively, compared to lead-exposed nontreated controls. The significantly better response observed with the simultaneous CVE/lead administration indicates that the immunomodulation effect of CVE plays an important

  14. The effect of cadmium on the growth and antioxidant response for freshwater algae Chlorella vulgaris.

    PubMed

    Cheng, Jinfeng; Qiu, Hongchen; Chang, Zhaoyang; Jiang, Zaimin; Yin, Wenke

    2016-01-01

    The objective of the present work was to evaluate the effect of exogenously applied cadmium on the physiological response of green algae Chlorella vulgaris. The study investigated the long-term effect (18 days) of cadmium on the levels of algae biomass, assimilation pigment composition, soluble protein, oxidative status (production of hydrogen peroxide and superoxide anion), antioxidant enzymes (such as superoxide dismutase, peroxidase, catalase and glutathione reductase enzyme) in C. vulgaris. The results showed that growth, the amount of chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids gradually decreased with increasing cadmium over 18 days exposure. Cadmium at concentration of 7 mg L(-1) inhibited algal growth expressed as the number of cells. Our research found that C. vulgaris has a high tolerance to cadmium. Contents of chlorophylls (Chl a and Chl b) and carotenoids (Car) of C. vulgaris was significantly decline with rising concentration of cadmium (p < 0.05). The decrease of 54.04 and 93.37 % in Chl a, 60.65 and 74.32 % in Chl b, 50.00 and 71.88 % in total carotenoids was noticed following the treatment with 3 and 7 mg L(-1) cadmium doses compared with control treatment, respectively. Cadmium treatments caused a significant change in the physiological competence (calculated as chlorophyll a/b) which increased with increasing Cd(II) doses up to 1 mg L(-1) but decreased at 3 mg L(-1). While accumulation of soluble protein was enhanced by presence of cadmium, the treatment with cadmium at 3 and 7 mg L(-1) increased the concentration of soluble proteins by 88, 95.8 % in C. vulgaris, respectively. Moreover, low doses of cadmium stimulated enzymatic (superoxide dismutase, catalase and glutathione reductase) in C. vulgaris, The content of peroxidase increased with the increasing cadmium concentration, and had slightly decreased at the concentration of 7 mg L(-1), but was still higher than control group, which showed that cadmium

  15. The effect of cadmium on the growth and antioxidant response for freshwater algae Chlorella vulgaris.

    PubMed

    Cheng, Jinfeng; Qiu, Hongchen; Chang, Zhaoyang; Jiang, Zaimin; Yin, Wenke

    2016-01-01

    The objective of the present work was to evaluate the effect of exogenously applied cadmium on the physiological response of green algae Chlorella vulgaris. The study investigated the long-term effect (18 days) of cadmium on the levels of algae biomass, assimilation pigment composition, soluble protein, oxidative status (production of hydrogen peroxide and superoxide anion), antioxidant enzymes (such as superoxide dismutase, peroxidase, catalase and glutathione reductase enzyme) in C. vulgaris. The results showed that growth, the amount of chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids gradually decreased with increasing cadmium over 18 days exposure. Cadmium at concentration of 7 mg L(-1) inhibited algal growth expressed as the number of cells. Our research found that C. vulgaris has a high tolerance to cadmium. Contents of chlorophylls (Chl a and Chl b) and carotenoids (Car) of C. vulgaris was significantly decline with rising concentration of cadmium (p < 0.05). The decrease of 54.04 and 93.37 % in Chl a, 60.65 and 74.32 % in Chl b, 50.00 and 71.88 % in total carotenoids was noticed following the treatment with 3 and 7 mg L(-1) cadmium doses compared with control treatment, respectively. Cadmium treatments caused a significant change in the physiological competence (calculated as chlorophyll a/b) which increased with increasing Cd(II) doses up to 1 mg L(-1) but decreased at 3 mg L(-1). While accumulation of soluble protein was enhanced by presence of cadmium, the treatment with cadmium at 3 and 7 mg L(-1) increased the concentration of soluble proteins by 88, 95.8 % in C. vulgaris, respectively. Moreover, low doses of cadmium stimulated enzymatic (superoxide dismutase, catalase and glutathione reductase) in C. vulgaris, The content of peroxidase increased with the increasing cadmium concentration, and had slightly decreased at the concentration of 7 mg L(-1), but was still higher than control group, which showed that cadmium

  16. Antagonistic interaction of selenomethionine enantiomers on methylmercury toxicity in the microalgae Chlorella sorokiniana.

    PubMed

    Moreno, Fernando; García-Barrera, Tamara; Gómez-Jacinto, Verónica; Gómez-Ariza, José Luis; Garbayo-Nores, Inés; Vílchez-Lobato, Carlos

    2014-02-01

    The protective effect of selenium against mercury toxicity is well known especially between selenomethionine and methylmercury and it has been studied in several living organisms, however information is lacking about the interaction of these species in Chlorella. Investigation into which chiral form of selenomethionine effectively acts against the toxic effects of methylmercury has not previously been carried out. In the present work, two control cultures and two cultures of C. sorokiniana were grown in standard medium with D,L-SeMet, L-SeMet or D-SeMet. After the experiment was started up MeHg(+) was added periodically to the cultures containing D,L-SeMet, L-SeMet, D-SeMet and to one of the control batches. The results show that both SeMet enantiomers counteract the toxicity of MeHg(+), by markedly increasing the total content of chlorophyll, carotenoids, as well as the dry weight and light dependent oxygen production, compared to the culture which is non pre-treated with SeMet and is only exposed to MeHg(+). The levels of MeHg(+) measured in cells are lower in the cultures pre-treated with SeMet indicating that the passage of MeHg(+) into the cells is negligible when carried out in the presence of SeMet, or that SeMet enhances the release of MeHg(+). On the other hand, L-SeMet is directly involved in the detoxification of MeHg(+), but the involvement of D-SeMet occurs only indirectly since it has been neither identified in the medium nor in C. sorokiniana after supplementation with this enantiomer. It may be that D-SeMet is transformed into SeMeSec and L-SeMet. Moreover, SeMeSec is almost totally released from the cells after 72 hours. No mercury-selenium complex was detected but, since the summation of the different species identified accounted only for 77% of the total selenium and mercury measured directly after sample digestion, it is possible that they are present in the form of an undetected Se-Hg complex. This hypothesis is supported by the decrease of

  17. Chlorella mirabilis as a Potential Species for Biomass Production in Low-Temperature Environment

    PubMed Central

    Shukla, S. P.; Kvíderová, J.; Tříska, J.; Elster, J.

    2013-01-01

    Successful adaptation/acclimatization to low temperatures in micro-algae is usually connected with production of specific biotechnologically important compounds. In this study, we evaluated the growth characteristics in a micro-scale mass cultivation of the Antarctic soil green alga Chlorella mirabilis under different nitrogen and carbon sources followed by analyses of fatty acid contents. The micro-scale mass cultivation was performed in stable (in-door) and variable (out-door) conditions during winter and/or early spring in the Czech Republic. In the in-door cultivation, the treatments for nitrogen and carbon sources determination included pure Z medium (control, Z), Z medium + 5% glycerol (ZG), Z medium + 5% glycerol + 50 μM KNO3 (ZGN), Z medium + 5% glycerol + 200 μM NH4Cl (ZGA), Z medium + 5% glycerol + 1 mM Na2CO3 (ZNC), Z medium + 5% glycerol + 1 mM Na2CO3 + 200 μM NH4Cl (ZGCA) and Z medium + 5% glycerol + 1 mM Na2CO3 + 50 μM KNO3 (ZGCN) and were performed at 15°C with an irradiance of 75 μmol m−2 s−1. During the out-door experiments, the night-day temperature ranged from −6.6 to 17.5°C (daily average 3.1 ± 5.3°C) and irradiance ranged from 0 to 2,300 μmol m−2 s−1 (daily average 1,500 ± 1,090 μmol m−2 s−1). Only the Z, ZG, ZGN, and ZGC treatments were used in the out-door cultivation. In the in-door mass cultivation, all nitrogen and carbon sources additions increased the growth rate with the exception of ZGA. When individual sources were considered, only the effect of 5% glycerol addition was significant. On the other hand, the growth rate decreased in the ZG and ZGN treatments in the out-door experiment, probably due to carbon limitation. Fatty acid composition showed increased production of linoleic acid in the glycerol treatments. The studied strain of C. mirabilis is proposed to be a promising source of linoleic acid in low

  18. Comparative characteristic of mitochondria ultrastructural organization in Chlorella cells under altered gravity conditions

    NASA Astrophysics Data System (ADS)

    Popova, A. F.

    2003-05-01

    Results from experiments that used cells from the unicellular alga Chlorella vulgaris (strain Larg-1) grown on a clinostat, demonstrated the occurrence of rearrangements in cellular organelles, including changes in the mitochondrial ultrastructure compared to controls. Changes in mitochondrial structure were observed in auto- and heterotrophic regimes of cells grown in altered gravity conditions, especially in long-term experiments. The mitochondrial rearrangements become apparent during cell proliferation, which resulted in an increase in the relative volume of mitochondria per cell: up to 2.7±0.3% in short-term clino-rotation (2.2±0.1% in the control) and up to 5.3±0.4% and 5.1±0.4% in long-term clino-rotation (2.3±0.2% in the control). The size of the mitochondria and their cristae increased in cells grown under long-time clino-rotation. In addition, hypertrophied organelles, not typical for this strain, were observed. These changes in the cells were accompanied by increased electron density of the matrix and a well-ordered topography of the cristae. To examine the separation of oxidative phosphorylation and respiration, an inhibitory agent 2,4-dinitrophenol (2,4-DNP) was applied to cells which resulted in insignificant volume changes of the mitochondria (2.5±0.4% versus 2.1±0.2% in the control). The increase of mitochondrial size with regularly arranged cristae, with more condensed matrix and extension of cristae areas of clino-rotated cells, may demonstrate higher functional activity of the mitochondria under altered gravity conditions. Changes observed early in clino-rotated cells, in particular the increased level of respiration, adenylate content (especially ATP) and more intensive electron-cytochemical reactions of Mg 2+-ATPase and succinat dehydrogenase (SDH) in mitochondria (including hypertrophic organelles), also suggest increased activity of mitochondria from cells grown under altered gravity conditions compared to controls.

  19. Inhibition of Pro-inflammatory Mediators and Cytokines by Chlorella Vulgaris Extracts

    PubMed Central

    Sibi, G.; Rabina, Santa

    2016-01-01

    Objective: The aim of this study was to determine the in vitro anti-inflammatory activities of solvent fractions from Chlorella vulgaris by inhibiting the production of pro-inflammatory mediators and cytokines. Methods: Methanolic extracts (80%) of C. vulgaris were prepared and partitioned with solvents of increasing polarity viz., n-hexane, chloroform, ethanol, and water. Various concentrations of the fractions were tested for cytotoxicity in RAW 264.7 cells using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, and the concentrations inducing cell growth inhibition by about 50% (IC50) were chosen for further studies. Lipopolysaccharide (LPS) stimulated RAW 264.7 cells were treated with varying concentrations of C. vulgaris fractions and examined for its effects on nitric oxide (NO) production by Griess assay. The release of prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6) were quantified using enzyme-linked immunosorbent assay using Celecoxib and polymyxin B as positive controls. Results: MTT assay revealed all the solvent fractions that inhibited cell growth in a dose-dependent manner. Of all the extracts, 80% methanolic extract exhibited the strongest anti-inflammatory activity by inhibiting NO production (P < 0.01), PGE2 (P < 0.05), TNF-α, and IL-6 (P < 0.001) release in LPS induced RAW 264.7 cells. Both hexane and chloroform fractions recorded a significant (P < 0.05) and dose-dependent inhibition of LPS induced inflammatory mediators and cytokines in vitro. The anti-inflammatory effect of ethanol and aqueous extracts was not significant in the study. Conclusion: The significant inhibition of inflammatory mediators and cytokines by fractions from C. vulgaris suggests that this microalga would be a potential source of developing anti-inflammatory agents and a good alternate for conventional steroidal and nonsteroidal anti-inflammatory drugs. SUMMARY C. vulgaris extracts have potential anti

  20. The Variability of the Photosynthetic Unit in Chlorella II. The Effect of Light Intensity and Cell Development on Photosynthesis, P-700 and Cytochrome f in Homocontinuous and Synchronous Cultures of Chlorella.

    PubMed

    Wilhelm, C; Wild, A

    1984-05-01

    The effect of light intensity of steady state photosynthesis, the contents of P-700 and cytochrome f was studied in homocontinuously grown Chlorella cells. The adaptation to higher light intensities drastically provokes the decrease of chlorophylls per dry weight, per packed cell volume and per cell. The light saturating curves show that high light grown cells produce threefold more oxygen per chlorophyll, whereas the oxygen evolution per cell is reduced by half. The rates of saturated photosynthesis per chlorophyll are directly correlated with increasing light intensities. The content of P-700 is slightly altered by light intensity. On the other hand, cytochrome f is changed in very strict accordance with the alterations of biomass productivity and photosynthetic capacity. The mathematical equation for the relationship between maximal photosynthesis and cytochrome f concentration is found to be linear with a correlation coefficient of 0.96. In addition to the results of homocontinuously grown Chlorella cells, the relationship between photosynthesis and the content of cytochrome f was analyzed in synchronous cultures. After the onset of light the photosynthetic activity rises as well as the content of cytochrome f. During the dark period, however, when the photosynthetic capacity is low, there still remains a high amount of cytochrome f. The results are discussed on the basis of the variability of the photosynthetic unit and the in-tactness of the thylakoid membrane. It is proposed to introduce the term of the «physiological photosynthetic unit» defined by the ratio of chlorophyll to cytochrome f. Its size is proved to be used as an indicator of the rate limiting step in the photosynthetic electron transport.

  1. Influence of phosphate on toxicity and bioaccumulation of arsenic in a soil isolate of microalga Chlorella sp.

    PubMed

    Bahar, Md Mezbaul; Megharaj, Mallavarapu; Naidu, Ravi

    2016-02-01

    In this study, the toxicity, biotransformation and bioaccumulation of arsenite and arsenate in a soil microalga, Chlorella sp., were investigated using different phosphate levels. The results indicated that arsenate was highly toxic than arsenite to the alga, and the phosphate limitation in growth media greatly enhanced arsenate toxicity. The uptake of arsenate in algal cells was more than that of arsenite, and the predominant species in the growth media was arsenate after 8 days of exposure to arsenite or arsenate, indicating arsenite oxidation by this microalga. Arsenate reduction was also observed when the alga was incubated in a phosphate-limiting growth medium. Similar to the process of biotransformation, the alga accumulated more arsenic when it was exposed to arsenate and preferably more in a phosphate-limiting condition. Although phosphate significantly influences the biotransformation and bioaccumulation of arsenic, the oxidizing ability and higher accumulation capacity of this alga have great potential for its application in arsenic bioremediation. PMID:26438364

  2. Three stage cultivation process of facultative strain of Chlorella sorokiniana for treating dairy farm effluent and lipid enhancement.

    PubMed

    Hena, S; Fatihah, N; Tabassum, S; Ismail, N

    2015-09-01

    Reserve lipids of microalgae are promising for biodiesel production. However, economically feasible and sustainable energy production from microalgae requires optimization of cultivation conditions for both biomass yield and lipid production of microalgae. Biomass yield and lipid production in microalgae are a contradictory problem because required conditions for both targets are different. Simultaneously, the mass cultivation of microalgae for biofuel production also depends extremely on the performance of the microalgae strains used. In this study a green unicellular microalgae Chlorella sorokiniana (DS6) isolated from the holding tanks of farm wastewater treatment plant using multi-step screening and acclimation procedures was found high-lipid producing facultative heterotrophic microalgae strain capable of growing on dairy farm effluent (DFE) for biodiesel feedstock and wastewater treatment. Morphological features and the phylogenetic analysis for the 18S rRNA identified the isolated strains. A novel three stage cultivation process of facultative strain of C. sorokiniana was examined for lipid production. PMID:26043271

  3. Triglyceride accumulation and fatty acid profile changes in Chlorella (Chlorophyta) during high pH-induced cell cycle inhibition

    SciTech Connect

    Guckert, J.B.; Cooksey, K.E. )

    1990-03-01

    Alkaline pH stress resulted in triglyceride (TG) accumulation in Chlorella CHLOR1 and was independent of medium nitrogen or carbon levels. Based on morphological observations, alkaline pH inhibited autospore release, thus increasing the time for cell cycle completion. Autospore release has been postulated to coincide with TG utilization within the microalgal cell division cycle. The alkaline pH stress affected lipid accumulation by inhibiting the cell division cycle prior to autospore release and, therefore, prior to TG utilization. Cells inhibited in this manner showed an increase in TG accumulation but a decrease in both membrane lipid classes (glycolipid and polar lipid). Unlike TG fatty acid profiles, membrane lipid fatty acid profiles were not stable during TG accumulation. The membrane profiles became similar to the TG, i.e. less unsaturated than in the membrane lipids of unstressed control cells.

  4. Protective effects of certain environmental factors on the toxicity of zinc, mercury, and methylmercury to Chlorella vulgaris

    SciTech Connect

    Rai, L.C.; Gaur, J.P.; Kumar, H.D.

    1981-08-01

    The specific growth rate and final yield of Chlorella vulgaris treated with zinc, mercury, and methylmercury declined with increase in metal concentration. Methylmercury was most toxic and at 1 x 10/sup -3/ mg/liter concentration it reduced survival by about 50%. Approximately 50% mortality occurred at 25 and 0.4 mg/liter concentration of zinc and mercury, respectively. The total chlorophyll content decreased and the carotenoids/chlorophyll ratio increased with increase in heavy metal concentration. Of the various factors investigated, pH, phosphate, and calcium produced a highly significant (P < 0.001) effect on metal toxicities, and magnesium produced a less significant effect (P < 0.1). The present study suggests that alkaline and hard eutrophic waters might help protect freshwater organisms against heavy metal toxicity.

  5. Fed-batch cultivation of Arthrospira and Chlorella in ammonia-rich wastewater: Optimization of nutrient removal and biomass production.

    PubMed

    Markou, Giorgos

    2015-10-01

    In the present work the cyanobacterium Arthrospira platensis and the microalga Chlorella vulgaris were fed-batch cultivated in ammonia-rich wastewater derived from the anaerobic digestion of poultry litter. Aim of the study was to maximize the biomass production along with the nutrient removal aiming to wastewater treatment. Ammonia and phosphorus removals were very high (>95%) for all cultures investigated. Both microorganisms were able to remove volatile fatty acids to an extent of >90%, indicating that they were capable of mixotrophic growth. Chemical oxygen demand and proteins were also removed in various degrees. In contrast, in all cultures carbohydrate concentration was increased. The biochemical composition of the microorganisms varied greatly and was influenced by the indicate that the nutrient availability. A. platensis accumulated carbohydrates (≈ 40%), while C. vulgaris accumulated lipids (≈ 50%), rendering them interesting for biofuel production.

  6. Influence of limiting factors on biomass and lipid productivities of axenic Chlorella vulgaris in photobioreactor under chemostat cultivation.

    PubMed

    Cho, Dae-Hyun; Ramanan, Rishiram; Heo, Jina; Shin, Dong-Sik; Oh, Hee-Mock; Kim, Hee-Sik

    2016-07-01

    The understanding of process parameters and limiting conditions on microalgal biomass and lipid productivities is scarce especially in chemostat cultivation. In this study, the factors limiting growth of axenic Chlorella vulgaris OW-01 in cylindrical photobioreactor under chemostat cultivation were overcome in two phases. Physiological and physicochemical analyses determined inorganic carbon, phosphorous and light intensity as major limiting factors. Their effect on system productivity was ascertained and optimized in the first phase resulting in maximum biomass and lipid productivities of 538 and 128 (mg/L/d), respectively. In the second phase, the effect of dilution rate was evaluated under optimized conditions. The biomass and lipid productivities in this phase reached to 1013 and 270 (mg/L/d), respectively at a dilution rate of 0.75d(-1), yielding >10-fold cumulative increase in productivities. The study demonstrates addressing resource limitations by constant monitoring and optimization of chemostat cultivation to achieve high biomass and lipid productivities in photobioreactors. PMID:27030956

  7. Influence of phosphate on toxicity and bioaccumulation of arsenic in a soil isolate of microalga Chlorella sp.

    PubMed

    Bahar, Md Mezbaul; Megharaj, Mallavarapu; Naidu, Ravi

    2016-02-01

    In this study, the toxicity, biotransformation and bioaccumulation of arsenite and arsenate in a soil microalga, Chlorella sp., were investigated using different phosphate levels. The results indicated that arsenate was highly toxic than arsenite to the alga, and the phosphate limitation in growth media greatly enhanced arsenate toxicity. The uptake of arsenate in algal cells was more than that of arsenite, and the predominant species in the growth media was arsenate after 8 days of exposure to arsenite or arsenate, indicating arsenite oxidation by this microalga. Arsenate reduction was also observed when the alga was incubated in a phosphate-limiting growth medium. Similar to the process of biotransformation, the alga accumulated more arsenic when it was exposed to arsenate and preferably more in a phosphate-limiting condition. Although phosphate significantly influences the biotransformation and bioaccumulation of arsenic, the oxidizing ability and higher accumulation capacity of this alga have great potential for its application in arsenic bioremediation.

  8. Highly efficient extraction and lipase-catalyzed transesterification of triglycerides from Chlorella sp. KR-1 for production of biodiesel.

    PubMed

    Lee, Ok Kyung; Kim, Young Hyun; Na, Jeong-Geol; Oh, You-Kwan; Lee, Eun Yeol

    2013-11-01

    We developed a method for the highly efficient lipid extraction and lipase-catalyzed transesterification of triglyceride from Chlorella sp. KR-1 using dimethyl carbonate (DMC). Almost all of the total lipids, approximately 38.9% (w/w) of microalgae dry weight, were extracted from the dried microalgae biomass using a DMC and methanol mixture (7:3 (v/v)). The extracted triglycerides were transesterified into fatty acid methyl esters (FAMEs) using Novozyme 435 as the biocatalyst in DMC. Herein, DMC was used as the reaction medium and acyl acceptor. The reaction conditions were optimized and the FAMEs yield was 293.82 mg FAMEs/g biomass in 6 h of reaction time at 60 °C in the presence of 0.2% (v/v) water. Novozyme 435 was reused more than ten times while maintaining relative FAMEs conversion that was greater than 90% of the initial FAMEs conversion. PMID:23999257

  9. Fed-batch cultivation of Arthrospira and Chlorella in ammonia-rich wastewater: Optimization of nutrient removal and biomass production.

    PubMed

    Markou, Giorgos

    2015-10-01

    In the present work the cyanobacterium Arthrospira platensis and the microalga Chlorella vulgaris were fed-batch cultivated in ammonia-rich wastewater derived from the anaerobic digestion of poultry litter. Aim of the study was to maximize the biomass production along with the nutrient removal aiming to wastewater treatment. Ammonia and phosphorus removals were very high (>95%) for all cultures investigated. Both microorganisms were able to remove volatile fatty acids to an extent of >90%, indicating that they were capable of mixotrophic growth. Chemical oxygen demand and proteins were also removed in various degrees. In contrast, in all cultures carbohydrate concentration was increased. The biochemical composition of the microorganisms varied greatly and was influenced by the indicate that the nutrient availability. A. platensis accumulated carbohydrates (≈ 40%), while C. vulgaris accumulated lipids (≈ 50%), rendering them interesting for biofuel production. PMID:26117233

  10. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa) fed Chlorella vulgaris and Scenedesmus acutus cultured on different media.

    PubMed

    Morales-Ventura, Jesús; Nandini, S; Sarma, S S S; Castellanos-Páez, Maria Elena

    2012-09-01

    Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold's basal) medium or the commercial liquid fertilizer (Bayfolan). Experiments were conducted at one algal concentration 1.0 x 10(6) cells/mL of C. vulgaris or its equivalent dry weight of 0.5 x 10(6) cells/mL of S. acutus. The population dynamics were tested at 23 +/- 1 degrees C in 100 mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates). For the life table experiments with M. macrocopa, we introduced 10 neonates (<24h old) into each test jar containing the specific algal type and concentration. For the rotifer experiments, we set 5mL tubes with one neonate each and 10 replicates for each algal species and culture medium. We found that the average rotifer life span was not influenced by the diet, but for M. macrocopa fed S. acutus cultured in Bold's medium, the average lifespan was significantly lower than with the other diets. The gross and net reproductive rates of A. fissa (ranging from 18-36 offspring per female) were significantly higher for C vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive rates for B. rubens than S. acutus diets. The reproductive rates of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase rate, derived from growth experiments of A. fissa and B. rubens

  11. Three stage cultivation process of facultative strain of Chlorella sorokiniana for treating dairy farm effluent and lipid enhancement.

    PubMed

    Hena, S; Fatihah, N; Tabassum, S; Ismail, N

    2015-09-01

    Reserve lipids of microalgae are promising for biodiesel production. However, economically feasible and sustainable energy production from microalgae requires optimization of cultivation conditions for both biomass yield and lipid production of microalgae. Biomass yield and lipid production in microalgae are a contradictory problem because required conditions for both targets are different. Simultaneously, the mass cultivation of microalgae for biofuel production also depends extremely on the performance of the microalgae strains used. In this study a green unicellular microalgae Chlorella sorokiniana (DS6) isolated from the holding tanks of farm wastewater treatment plant using multi-step screening and acclimation procedures was found high-lipid producing facultative heterotrophic microalgae strain capable of growing on dairy farm effluent (DFE) for biodiesel feedstock and wastewater treatment. Morphological features and the phylogenetic analysis for the 18S rRNA identified the isolated strains. A novel three stage cultivation process of facultative strain of C. sorokiniana was examined for lipid production.

  12. Enhancing growth rate and lipid yield of Chlorella with nuclear irradiation under high salt and CO2 stress.

    PubMed

    Cheng, Jun; Lu, Hongxiang; Huang, Yun; Li, Ke; Huang, Rui; Zhou, Junhu; Cen, Kefa

    2016-03-01

    In order to produce biodiesel from microalgae cultured with abundant seawater, Chlorella sp. was mutated with (137)Se-γ ray irradiation and domesticated with f/2 seawater culture medium (salinity=3 wt.%) under 15 vol.% CO2 stress. Biomass yield of the mutant increased by 25% compared with wild species and lipid content increased to 54.9%. When nitrogen and phosphorus concentrations in the initial substrate increased, the increased propagation speed of the mutant resulted in decreased cell diameter by 26.6% and decreased cell wall thickness by 69.7%. The dramatically increased biomass yield of the mutant with sufficient initial substrate and relative nitrogen starvation in the later growth period with continuous 15 vol.% CO2 led to an increased lipid yield of 1.0 g/L. The long-chain unsaturated fatty acids increased, whereas short-chain saturated fatty acids decreased.

  13. The influence of extracellular compounds produced by selected Baltic cyanobacteria, diatoms and dinoflagellates on growth of green algae Chlorella vulgaris

    NASA Astrophysics Data System (ADS)

    Żak, Adam; Kosakowska, Alicja

    2015-12-01

    Secondary metabolites produced by bacteria, fungi, algae and plants could affect the growth and development of biological and agricultural systems. This natural process that occurs worldwide is known as allelopathy. The main goal of this work was to investigate the influence of metabolites obtained from phytoplankton monocultures on the growth of green algae Chlorella vulgaris. We selected 6 species occurring in the Baltic Sea from 3 different taxonomic groups: cyanobacteria (Aphanizomenon flos-aquae; Planktothrix agardhii), diatoms (Thalassiosira pseudonana; Chaetoceros wighamii) and dinoflagellates (Alexandrium ostenfeldii; Prorocentrum minimum). In this study we have demonstrated that some of selected organisms caused allelopathic effects against microalgae. Both the negative and positive effects of collected cell-free filtrates on C. vulgaris growth, chlorophyll a concentration and fluorescence parameters (OJIP, QY, NPQ) have been observed. No evidence has been found for the impact on morphology and viability of C. vulgaris cells.

  14. Bioethanol production from carbohydrate-enriched residual biomass obtained after lipid extraction of Chlorella sp. KR-1.

    PubMed

    Lee, Ok Kyung; Oh, You-Kwan; Lee, Eun Yeol

    2015-11-01

    The residual biomass of Chlorella sp. KR-1 obtained after lipid extraction was used for saccharification and bioethanol production. The carbohydrate was saccharified using simple enzymatic and chemical methods using Pectinex at pH 5.5 and 45°C and 0.3N HCl at 121°C for 15min with 76.9% and 98.2% yield, respectively, without any pretreatment. The residual biomass contained 49.7% carbohydrate consisting of 82.4% fermentable sugar and 17.6% non-fermentable sugar, which is valuable for bioethanol fermentation. Approximately 98.2% of the total carbohydrate was converted into monosaccharide (fermentable+non-fermentable sugar) using dilute acid saccharification. The fermentable sugar was subsequently fermented to bioethanol through separate hydrolysis and fermentation with a fermentation yield of 79.3%. Overall, 0.4g ethanol/g fermentable sugar and 0.16g ethanol/g residual biomass were produced.

  15. Effect of light intensity on the degree of ammonia toxicity on PSII activity of Arthrospira platensis and Chlorella vulgaris.

    PubMed

    Markou, Giorgos; Muylaert, Koenraad

    2016-09-01

    Herein the effect of increasing light intensity on the degree of ammonia toxicity and its impact on the photosynthetic performance of Arthrospira and Chlorella was investigated using Chl fluorescence as a technique to characterize their photosystem II (PSII) activity. The results revealed that the increase of light intensity amplifies the ammonia toxicity on PSII. Chl fluorescence transients shown that at a given free ammonia (FA) concentration (100mg-N/L), the photochemistry potential decreased by increasing light intensity. The inhibition of the PSII was not reversible either by re-incubating the cells under dark or under decreased FA concentration. Moreover, the decrease of photochemical and non-photochemical quenching (NPQ) of fluorescence suggest that ammonia toxicity decreases the open available PSII centers, as well the inability of PSII to transfer the generated electrons beyond QA. The collapse of NPQ suggests that ammonia toxicity inhibits the photoprotection mechanism(s) and hence renders PSII more sensitive to photoinhibition. PMID:27262720

  16. Changes in the metabolism of the microalga Chlorella vulgaris when coimmobilized in alginate with the nitrogen-fixing Phyllobacterium myrsinacearum.

    PubMed

    Gonzalez-Bashan, L E; Lebsky, V K; Hernandez, J P; Bustillos, J J; Bashan, Y

    2000-07-01

    In an agroindustrial wastewater pond, a naturally occurring unicellular microalga, Chlorella vulgaris, was closely associated with the terrestrial plant-associative N2-fixing bacterium Phyllobacterium myrsinacearum. When the two microorganisms were artificially coimmobilized in alginate beads, they shared the same internal bead cavities, and the production of five microalgal pigments increased, but there were no effects on the number of the cells or the biomass of the microalga. The association, however, reduces the ability of C. vulgaris to remove ammonium ions and phosphorus from water. The bacterium produced nitrate from ammonium in synthetic wastewater with or without the presence of the microalga, and fixed nitrogen in two culture media. Our results suggest that interactions between microalgae and associative bacteria should be considered when cultivating microalgae for wastewater treatment.

  17. Isolation and purification of canthaxanthin from the microalga Chlorella zofingiensis by high-speed counter-current chromatography.

    PubMed

    Hua-Bin, Li; Fan, King-Wai; Chen, Feng

    2006-03-01

    Certain microalgae are considered to be a potential source of canthaxanthin, which possesses strong antioxidant and anticancer activities. A high-speed counter-current chromatography (HSCCC) method was developed for the separation and purification of canthaxanthin from the microalga Chlorella zofingiensis. The crude canthaxanthin was obtained by extraction with organic solvents after the microalgal sample had been saponified. Preparative HSCCC, with a two-phase solvent system composed of n-hexane-ethanol-water (10:9:1 v/v), was successfully performed yielding canthaxanthin at 98.7% purity from 150 mg of the crude extract (2.1% canthaxanthin) in a one-step separation. The recovery of canthaxanthin was 92.3%. This was the first report that canthaxanthin was successfully separated and purified from microalgae.

  18. Impact of changes in broth composition on Chlorella vulgaris cultivation in a membrane photobioreactor (MPBR) with permeate recycle.

    PubMed

    Discart, V; Bilad, M R; Marbelia, L; Vankelecom, I F J

    2014-01-01

    A membrane photobioreactor (MPBR) is a proven and very useful concept in which microalgae can be simultaneously cultivated and pre-harvested. However, the behavior with respect to accumulation of algogenic organic matter, including transparent exopolymeric particles (TEPs), counter ions and unassimilated nutrients due to the recycling of the medium is still unclear, even though the understanding of this behavior is essential for the optimization of microalgae processing. Therefore, the dynamics of these compounds, especially TEPs, during coupled cultivation and harvesting of Chlorella vulgaris in an MPBR with permeate recycle are addressed in this study. Results show that TEPs are secreted during algae cell growth, and that their presence is thus inevitable. In the system with permeate recycle, substances such as counter ions and unassimilated nutrients get accumulated in the system. This was proven to limit the algae growth, together with the occurrence of bioflocculation due to an increasing broth pH.

  19. Lipid Profile Remodeling in Response to Nitrogen Deprivation in the Microalgae Chlorella sp. (Trebouxiophyceae) and Nannochloropsis sp. (Eustigmatophyceae)

    PubMed Central

    Olmstead, Ian L. D.; Bergamin, Amanda; Shears, Melanie J.; Dias, Daniel A.; Kentish, Sandra E.; Scales, Peter J.; Botté, Cyrille Y.; Callahan, Damien L.

    2014-01-01

    Many species of microalgae produce greatly enhanced amounts of triacylglycerides (TAGs), the key product for biodiesel production, in response to specific environmental stresses. Improvement of TAG production by microalgae through optimization of growth regimes is of great interest. This relies on understanding microalgal lipid metabolism in relation to stress response in particular the deprivation of nutrients that can induce enhanced TAG synthesis. In this study, a detailed investigation of changes in lipid composition in Chlorella sp. and Nannochloropsis sp. in response to nitrogen deprivation (N-deprivation) was performed to provide novel mechanistic insights into the lipidome during stress. As expected, an increase in TAGs and an overall decrease in polar lipids were observed. However, while most membrane lipid classes (phosphoglycerolipids and glycolipids) were found to decrease, the non-nitrogen containing phosphatidylglycerol levels increased considerably in both algae from initially low levels. Of particular significance, it was observed that the acyl composition of TAGs in Nannochloropsis sp. remain relatively constant, whereas Chlorella sp. showed greater variability following N-deprivation. In both algae the overall fatty acid profiles of the polar lipid classes were largely unaffected by N-deprivation, suggesting a specific FA profile for each compartment is maintained to enable continued function despite considerable reductions in the amount of these lipids. The changes observed in the overall fatty acid profile were due primarily to the decrease in proportion of polar lipids to TAGs. This study provides the most detailed lipidomic information on two different microalgae with utility in biodiesel production and nutraceutical industries and proposes the mechanisms for this rearrangement. This research also highlights the usefulness of the latest MS-based approaches for microalgae lipid research. PMID:25171084

  20. Genome-based metabolic mapping and 13C flux analysis reveal systematic properties of an oleaginous microalga Chlorella protothecoides.

    PubMed

    Wu, Chao; Xiong, Wei; Dai, Junbiao; Wu, Qingyu

    2015-02-01

    Integrated and genome-based flux balance analysis, metabolomics, and (13)C-label profiling of phototrophic and heterotrophic metabolism in Chlorella protothecoides, an oleaginous green alga for biofuel. The green alga Chlorella protothecoides, capable of autotrophic and heterotrophic growth with rapid lipid synthesis, is a promising candidate for biofuel production. Based on the newly available genome knowledge of the alga, we reconstructed the compartmentalized metabolic network consisting of 272 metabolic reactions, 270 enzymes, and 461 encoding genes and simulated the growth in different cultivation conditions with flux balance analysis. Phenotype-phase plane analysis shows conditions achieving theoretical maximum of the biomass and corresponding fatty acid-producing rate for phototrophic cells (the ratio of photon uptake rate to CO2 uptake rate equals 8.4) and heterotrophic ones (the glucose uptake rate to O2 consumption rate reaches 2.4), respectively. Isotope-assisted liquid chromatography-mass spectrometry/mass spectrometry reveals higher metabolite concentrations in the glycolytic pathway and the tricarboxylic acid cycle in heterotrophic cells compared with autotrophic cells. We also observed enhanced levels of ATP, nicotinamide adenine dinucleotide (phosphate), reduced, acetyl-Coenzyme A, and malonyl-Coenzyme A in heterotrophic cells consistently, consistent with a strong activity of lipid synthesis. To profile the flux map in experimental conditions, we applied nonstationary (13)C metabolic flux analysis as a complementing strategy to flux balance analysis. The result reveals negligible photorespiratory fluxes and a metabolically low active tricarboxylic acid cycle in phototrophic C. protothecoides. In comparison, high throughput of amphibolic reactions and the tricarboxylic acid cycle with no glyoxylate shunt activities were measured for heterotrophic cells. Taken together, the metabolic network modeling assisted by experimental metabolomics and (13)C

  1. Effects of Nitrogen Sources and C/N Ratios on the Lipid-Producing Potential of Chlorella sp. HQ.

    PubMed

    Zhan, Jingjing; Hong, Yu; Hu, Hongying

    2016-07-28

    Microalgae are being researched for their potential as attractive biofuel feedstock, particularly for their lipid production. For maximizing biofuel production, it is necessary to explore the effects of environmental factors on algal lipid-producing potential. In this study, the effects of nitrogen (N) sources (NO2-N, NO3-N, urea-N, NH4-N, and N-deficiency) and carbon-to-nitrogen ratios (C/N= 0, 1.0, 3.0, and 5.0) on algal lipid-producing potential of Chlorella sp. HQ were investigated. The results showed that for Chlorella growth and lipid accumulation potential, NO2-N was the best amongst the nitrogen sources, and NO3-N and urea-N also contributed to algal growth and lipid accumulation potential, but NH4-N and N-deficiency instead caused inhibitory effects. Moreover, the results indicated that algal lipid-producing potential was related to C/N ratios. With NO2-N treatment and carbon addition (C/N = 1.0, 3.0, and 5.0), total lipid yield was enhanced by 12.96-20.37%, but triacylglycerol (TAG) yields decreased by 25.52-94.31%. As for NO3-N treatment, carbon addition led to a 17.82-57.43%/ 25.86-82.67% reduction of total lipid/TAG yields. When NH4-N was used as the nitrogen source, total lipid/TAG yields were increased by 46.67-113.33%/28.99-74.76% with carbon addition. The total lipid/TAG yields of urea-N treatment varied with C/N ratios. Overall, the highest TAG yield (TAG yield: 38.75 ± 5.21 mg/l; TAG content: 44.16 ± 4.35%) was achieved under NO2-N treatment without carbon addition (C/N = 0), the condition that had merit for biofuel production. PMID:27090186

  2. Genome-Based Metabolic Mapping and 13C Flux Analysis Reveal Systematic Properties of an Oleaginous Microalga Chlorella protothecoides

    DOE PAGESBeta

    Wu, Chao; Xiong, Wei; Dai, Junbiao; Wu, Qingyu

    2014-12-15

    We report that integrated and genome-based flux balance analysis, metabolomics, and 13C-label profiling of phototrophic and heterotrophic metabolism in Chlorella protothecoides, an oleaginous green alga for biofuel. The green alga Chlorella protothecoides, capable of autotrophic and heterotrophic growth with rapid lipid synthesis, is a promising candidate for biofuel production. Based on the newly available genome knowledge of the alga, we reconstructed the compartmentalized metabolic network consisting of 272 metabolic reactions, 270 enzymes, and 461 encoding genes and simulated the growth in different cultivation conditions with flux balance analysis. Phenotype-phase plane analysis shows conditions achieving theoretical maximum of the biomass andmore » corresponding fatty acid-producing rate for phototrophic cells (the ratio of photon uptake rate to CO2 uptake rate equals 8.4) and heterotrophic ones (the glucose uptake rate to O2 consumption rate reaches 2.4), respectively. Isotope-assisted liquid chromatography-mass spectrometry/mass spectrometry reveals higher metabolite concentrations in the glycolytic pathway and the tricarboxylic acid cycle in heterotrophic cells compared with autotrophic cells. We also observed enhanced levels of ATP, nicotinamide adenine dinucleotide (phosphate), reduced, acetyl-Coenzyme A, and malonyl-Coenzyme A in heterotrophic cells consistently, consistent with a strong activity of lipid synthesis. To profile the flux map in experimental conditions, we applied nonstationary 13C metabolic flux analysis as a complementing strategy to flux balance analysis. We found that the result reveals negligible photorespiratory fluxes and a metabolically low active tricarboxylic acid cycle in phototrophic C. protothecoides. In comparison, high throughput of amphibolic reactions and the tricarboxylic acid cycle with no glyoxylate shunt activities were measured for heterotrophic cells. Lastly, taken together, the metabolic network modeling assisted

  3. Interactive effect of brassinosteroids and cytokinins on growth, chlorophyll, monosaccharide and protein content in the green alga Chlorella vulgaris (Trebouxiophyceae).

    PubMed

    Bajguz, Andrzej; Piotrowska-Niczyporuk, Alicja

    2014-07-01

    Interaction between brassinosteroids (BRs) (brassinolide, BL; 24-epibrassinolide, 24-epiBL; 28-homobrassinolide, 28-homoBL; castasterone, CS; 24-epicastasterone, 24-epiCS; 28-homocastasterone, 28-homoCS) and adenine- (trans-zeatin, tZ; kinetin, Kin) as well as phenylurea-type (1,3-diphenylurea, DPU) cytokinins (CKs) in the regulation of cell number, phytohormone level and the content of chlorophyll, monosaccharide and protein in unicellular green alga Chlorella vulgaris (Trebouxiophyceae) were examined. Chlorella vulgaris exhibited sensitivity to CKs in the following order of their stimulating properties: 10 nM tZ > 100 nM Kin >1 μM DPU. Exogenously applied BRs possessed the highest biological activity in algal cells at concentration of 10 nM. Among the BRs, BL was characterized by the highest activity, while 28-homoCS - by the lowest. The considerable increase in the level of all endogenous BRs by 27-46% was observed in C. vulgaris culture treated with exogenous 10 nM tZ. It can be speculated that CKs may stimulate BR activity in C. vulgaris by inducing the accumulation of endogenous BRs. CKs interacted synergistically with BRs increasing the number of cells and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for BL applied in combination with tZ, whereas the lowest in the culture treated with both 28-homoCS and DPU. However, regardless of the applied mixture of BRs with CKs, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone in unicellular green alga C. vulgaris.

  4. Glutamine Assimilation and Feedback Regulation of L-acetyl-N-glutamate Kinase Activity in Chlorella variabilis NC64A Results in Changes in Arginine Pools.

    PubMed

    Minaeva, Ekaterina; Forchhammer, Karl; Ermilova, Elena

    2015-11-01

    Glutamine is a metabolite of central importance in nitrogen metabolism of microorganisms and plants. The Chlorella PII signaling protein controls, in a glutamine-dependent manner, the key enzyme of the ornithine/arginine biosynthesis pathway, N-acetyl-L-glutamate kinase (NAGK) that leads to arginine formation. We provide evidence that glutamine promotes effective growth of C. variabilis strain NC64A. The present study shows that externally supplied glutamine directly influences the internal pool of arginine in NC64A. Glutamine synthetase (GS) catalyzes the ATP-dependent conversion of glutamate and ammonium to glutamine. The results of this study demonstrate that glutamine acts as a negative effector of GS activity. These data emphasize the importance of glutamine-dependent coupling of metabolism and signaling as components of an efficient pathway allowing the maintenance of metabolic homeostasis and sustaining growth of Chlorella.

  5. Glutamine Assimilation and Feedback Regulation of L-acetyl-N-glutamate Kinase Activity in Chlorella variabilis NC64A Results in Changes in Arginine Pools.

    PubMed

    Minaeva, Ekaterina; Forchhammer, Karl; Ermilova, Elena

    2015-11-01

    Glutamine is a metabolite of central importance in nitrogen metabolism of microorganisms and plants. The Chlorella PII signaling protein controls, in a glutamine-dependent manner, the key enzyme of the ornithine/arginine biosynthesis pathway, N-acetyl-L-glutamate kinase (NAGK) that leads to arginine formation. We provide evidence that glutamine promotes effective growth of C. variabilis strain NC64A. The present study shows that externally supplied glutamine directly influences the internal pool of arginine in NC64A. Glutamine synthetase (GS) catalyzes the ATP-dependent conversion of glutamate and ammonium to glutamine. The results of this study demonstrate that glutamine acts as a negative effector of GS activity. These data emphasize the importance of glutamine-dependent coupling of metabolism and signaling as components of an efficient pathway allowing the maintenance of metabolic homeostasis and sustaining growth of Chlorella. PMID:26356535

  6. Kinetics of nutrient removal and expression of extracellular polymeric substances of the microalgae, Chlorella sp. and Micractinium sp., in wastewater treatment.

    PubMed

    Wang, Meng; Kuo-Dahab, Wenye Camilla; Dolan, Sona; Park, Chul

    2014-02-01

    Two species of green algae, Chlorella sp. and Micractinium sp., were cultivated in primary effluent wastewater and high-strength wastewater (a mixture of anaerobic digestion centrate and primary effluent) to study nutrient removal and EPS (extracellular polymeric substances) expression during their growth. The high N concentration and P-limited condition in the mixed wastewater (total N=197 mg/L; N/P mass ratio=56) led to about 3 times greater specific N removal rate than the primary effluent set, indicating that algal cells growing in N-rich wastewater had N over-uptake. Both Chlorella and Micractinium grown in the high-strength wastewater also produced larger amounts of protein EPS, possibly accounting for higher N uptake in those cultivation sets. These results suggest that different types of wastewater could cause different nutrient removal kinetics and EPS expression by algae, which may subsequently influence harvesting and anaerobic digestion of their biomass.

  7. Kinetics of nutrient removal and expression of extracellular polymeric substances of the microalgae, Chlorella sp. and Micractinium sp., in wastewater treatment.

    PubMed

    Wang, Meng; Kuo-Dahab, Wenye Camilla; Dolan, Sona; Park, Chul

    2014-02-01

    Two species of green algae, Chlorella sp. and Micractinium sp., were cultivated in primary effluent wastewater and high-strength wastewater (a mixture of anaerobic digestion centrate and primary effluent) to study nutrient removal and EPS (extracellular polymeric substances) expression during their growth. The high N concentration and P-limited condition in the mixed wastewater (total N=197 mg/L; N/P mass ratio=56) led to about 3 times greater specific N removal rate than the primary effluent set, indicating that algal cells growing in N-rich wastewater had N over-uptake. Both Chlorella and Micractinium grown in the high-strength wastewater also produced larger amounts of protein EPS, possibly accounting for higher N uptake in those cultivation sets. These results suggest that different types of wastewater could cause different nutrient removal kinetics and EPS expression by algae, which may subsequently influence harvesting and anaerobic digestion of their biomass. PMID:24384320

  8. Characteristics of lipid extraction from Chlorella sp. cultivated in outdoor raceway ponds with mixture of ethyl acetate and ethanol for biodiesel production.

    PubMed

    Lu, Weidong; Wang, Zhongming; Yuan, Zhenhong

    2015-09-01

    In this work, neutral lipids (NLs) extraction capacity and selectivity of six solvents were firstly compared. In addition, an eco-friendly solvent combination of ethyl acetate and ethanol (EA/E) was proposed and tested for lipid extraction from Chlorella sp. cultivated in outdoor raceway ponds and effect of extraction variables on lipid yield were intensively studied. Results indicated that lipid extraction yield was increased with solvent to biomass ratio but did not vary significantly when the value exceeded 20:1. Lipid yield was found to be strongly dependent on extraction temperature and time. Finally, fatty acid profiles of lipid were determined and results indicated that the major components were octadecanoic acid, palmitic acid, linoleic acid and linolenic acid, demonstrating that the lipid extracted from the Chlorella sp. cultivated in outdoor raceway ponds by EA/E was suitable feedstock for biodiesel production.

  9. Conversion of membrane lipid acyl groups to triacylglycerol and formation of lipid bodies upon nitrogen starvation in biofuel green algae Chlorella UTEX29.

    PubMed

    Goncalves, Elton C; Johnson, Jodie V; Rathinasabapathi, Bala

    2013-11-01

    Algal lipids are ideal biofuel sources. Our objective was to determine the contributors to triacylglycerol (TAG) accumulation and lipid body formation in Chlorella UTEX29 under nitrogen (N) deprivation. A fivefold increase in intracellular lipids following N starvation for 24 h confirmed the oleaginous characteristics of UTEX29. Ultrastructural studies revealed increased number of lipid bodies and decreased starch granules in N-starved cells compared to N-replete cells. Lipid bodies were observed as early as 3 h after N removal and plastids collapsed after 48 h of stress. Moreover, the identification of intracellular pyrenoids and differences in the expected nutritional requirements for Chlorella protothecoides (as UTEX29 is currently classified) led us to conduct a phylogenetic study using 18S and actin cDNA sequences. This indicated UTEX29 to be more phylogenetically related to Chlorella vulgaris. To investigate the fate of different lipids after N starvation, radiolabeling using ¹⁴C-acetate was used. A significant decrease in ¹⁴C-galactolipids and phospholipids matched the increase in ¹⁴C-TAG starting at 3 h of N starvation, consistent with acyl groups from structural lipids as sources for TAG under N starvation. These results have important implications for the identification of key steps controlling oil accumulation in N-starved biofuel algae and demonstrate membrane recycling during lipid body formation.

  10. Benefits of Preventive Administration of Chlorella sp. on Visceral Pain and Cystitis Induced by a Single Administration of Cyclophosphamide in Female Wistar Rat.

    PubMed

    Hidalgo-Lucas, Sophie; Rozan, Pascale; Guérin-Deremaux, Laetitia; Baert, Blandine; Violle, Nicolas; Saniez-Degrave, Marie-Hélène; Bisson, Jean-François

    2016-05-01

    Chlorella sp. is a green microalgae containing nutrients, vitamins, minerals, and chlorophyll. In some communities, Chlorella sp. is a traditional medicinal plant used for the management of inflammation-related diseases. In a rat model, ROQUETTE Chlorella sp. (RCs) benefits were investigated on visceral pain and associated inflammatory parameters related to cystitis both induced by cyclophosphamide (CYP). RCs was orally administered every day from day 1-16 (250 and 500 mg/kg body weight). Six hours after an intraperitoneal injection of 200 mg/kg body weight of CYP, body temperature, general behavior, food intake, and body weight were recorded. Twenty-four hours after CYP injection, rats were tested in two behavioral tests, an open field and the aversive light stimulus avoidance conditioning test, to evaluate the influence of pain on general activity and learning ability of rats. After euthanasia, bladders were weighed, their thickness was scored, and the urinary hemoglobin was measured. RCs orally administered at the two dosages significantly reduced visceral pain and associated inflammatory parameters related to cystitis both induced by CYP injection, and improved rat behavior. To conclude, RCs demonstrated beneficial effects against visceral pain and cystitis. PMID:27152976

  11. Toxicity, biotransformation, and mode of action of arsenic in two freshwater microalgae (Chlorella sp. and Monoraphidium arcuatum).

    PubMed

    Levy, Jacqueline L; Stauber, Jennifer L; Adams, Merrin S; Maher, William A; Kirby, Jason K; Jolley, Dianne F

    2005-10-01

    The toxicity of As(V) and As(III) to two axenic tropical freshwater microalgae, Chlorella sp. and Monoraphidium arcuatum, was determined using 72-h growth rate-inhibition bioassays. Both organisms were tolerant to As(III) (72-h concentration to cause 50% inhibition of growth rate [IC50], of 25 and 15 mg As[III]/L, respectively). Chlorella sp. also was tolerant to As(V) with no effect on growth rate over 72 h at concentrations up to 0.8 mg/L (72-h IC50 of 25 mg As[V]/L). Monoraphidium arcuatum was more sensitive to As(V) (72-h IC50 of 0.25 mg As[V]/L). An increase in phosphate in the growth medium (0.15-1.5 mg PO4(3-)/L) decreased toxicity, i.e., the 72-h IC50 value for M. arcuatum increased from 0.25 mg As(V)/L to 4.5 mg As(V)/L, while extracellular As and intracellular As decreased, indicating competition between arsenate and phosphate for cellular uptake. Both microalgae reduced As(V) to As(III) in the cell, with further biological transformation to methylated species (monomethyl arsonic acid and dimethyl arsinic acid) and phosphate arsenoriboside. Less than 0.01% of added As(V) was incorporated into algal cells, suggesting that bioaccumulation and subsequent methylation was not the primary mode of detoxification. When exposed to As(V), both species reduced As(V) to As(III); however, only M. arcuatum excreted As(III) into solution. Intracellular arsenic reduction may be coupled to thiol oxidation in both species. Arsenic toxicity most likely was due to arsenite accumulation in the cell, when the ability to excrete and/or methylate arsenite was overwhelmed at high arsenic concentrations. Arsenite may bind to intracellular thiols, such as glutathione, potentially disrupting the ratio of reduced to oxidized glutathione and, consequently, inhibiting cell division. PMID:16268166

  12. The effect of water hardness on the toxicity of uranium to a tropical freshwater alga Chlorella sp.

    PubMed

    Charles, Amanda L; Markich, Scott J; Stauber, Jennifer L; De Filippis, Lou F

    2002-10-01

    Uranium (U) derived from mining activities is of potential ecotoxicological concern to freshwater biota in tropical northern Australia. Few data are available on the effects of water hardness (Ca and/or Mg), which is elevated in U mine wastewaters, on the toxicity and bioavailability of U to freshwater biota, particularly algae. This study determined the effect of water hardness (8, 40, 100 and 400 mg CaCO(3) x l(-1), added as calcium (Ca) and magnesium (Mg) sulphate) on the toxicity (72 h growth rate inhibition) of U to the unicellular green alga, Chlorella sp., in synthetic freshwater, at constant pH (7.0) and alkalinity (8 mg CaCO(3) x l(-1)), similar in chemical composition to sandy coastal streams in tropical northern Australia. A 50-fold increase in water hardness resulted in a 5-fold decrease (PChlorella sp. (i.e. the 72 h EC(50) increased from 56 to 270 micro g U l(-1)). Possible explanation for the ameliorative effect of water hardness includes: (i) competition between U and Ca and/or Mg for binding sites on the cell surface; and (ii) a change in U speciation, and hence, bioavailability. Results showed that extracellular (cell-surface) and intracellular U concentrations significantly (P<0.05) decreased (2-5-fold) as water hardness increased from 8 to 400 mg CaCO(3)x l(-1). Calculation of U speciation using the geochemical model HARPHRQ showed that there were no significant (P>0.05) differences in the predicted speciation (% distribution) of U amongst the four water hardness levels. The reduction in U toxicity with increasing water hardness was most likely due to competition between U and Ca and/or Mg for binding sites on the algal cell surface. The minimum detectable effect concentrations of U were approximately 3 and 24 times higher (at 8 and 400 mg CaCO(3)x l(-1) hardness, respectively) than the national interim U guideline value (0.5 micro g x l(-1)) for protecting aquatic ecosystems. Overall, the results reinforce the

  13. Effects of alterd Gravity and Phosphorilation inhibitor 2.4-Dinitrophenole on Mitochondria Ultrastructural Organization in Chlorella Cells

    NASA Astrophysics Data System (ADS)

    Popova, A.

    The results of the experiments with two species of a green alga ?hlorella in spaceflight conditions and under altered gravity testified that the regular rearrangements has been revealed first of all in the cell mitochondriome. Such reorganizations were observed at auto- and geterotrophic regimes of the culture growth in the experiments of average duration (9-18 days) and also in long-term experiments (30 days - 4.5 months) (Popova, 1999). The mitochondria rearrangements become apparent at intensification of the cell proliferation, which results in increasing a relative volume of the mitohondria per cell (up to 5.3 % in microgravity compared to the control - 2.1 %). Moreover, the size of these organelles and their cristae increased in the experimental cells. The indicated mitochondria changes were accompanied by intensifying the electron density of a matrix and often by well-ordered topography of the cristae. Taking into account that the main set of the enzymes catalyzing the oxidative phosphorylation and conduction of the electrons are localized in the cristae membranes, the considerable growth of the mitochondria size and the cristae areas testified probably about a high functional activity of these organelles. Our investigations were carried out with the purpose to check the functional state of mitochondria under altered gravity (using slow horizontal clinorotator) and under influence of the inhibitory agent, separating an oxidation and oxidative phosphorylation. The ultrastructural peculiarities of the mitochondria as the energetic organelles were studied under the different 2,4- dinitrophenole concentrations and during the different terms of clinoritation at the logarithmic and stationary phases of Chlorella culture growth. The various characters of the mitochondria rearrangements and their relative volumes per cell were revealed under 2,4-dinitrophenole influence compared to the different terms of microgravity and altered gravity influences. The obtained

  14. Bimolecular quenching of excitons and fluorescence in the photosynthetic unit.

    PubMed Central

    Swenberg, C E; Geacintov, N E; Pope, M

    1976-01-01

    The recent results of Campillo et al. and Mauzerall on the quenching of the fluorescence of chlorophyll a in Chlorella pyrenoidosa as a function of the intensity of the laser excitation pulses are rationalized by applying a model invoking singlet-singlet exciton annihilation. PMID:990396

  15. Light attenuates lipid accumulation while enhancing cell proliferation and starch synthesis in the glucose-fed oleaginous microalga Chlorella zofingiensis.

    PubMed

    Chen, Tianpeng; Liu, Jin; Guo, Bingbing; Ma, Xiaonian; Sun, Peipei; Liu, Bin; Chen, Feng

    2015-10-07

    The objective of this study was to investigate the effect of light on lipid and starch accumulation in the oleaginous green algae Chlorella zofingiensis supplemented with glucose. C. zofingiensis, when fed with 30 g/L glucose, synthesized lipids up to 0.531 g/g dry weight; while in the presence of light, the lipid content dropped down to 0.352 g/g dry weight. Lipid yield on glucose was 0.184 g/g glucose, 14% higher than that cultured with light. The light-mediated lipid reduction was accompanied by the down-regulation of fatty acid biosynthetic genes at the transcriptional level. Furthermore, light promoted cell proliferation, starch accumulation, and the starch yield based on glucose. Taken together, light may attenuate lipid accumulation, possibly through the inhibition of lipid biosynthetic pathway, leading to more carbon flux from glucose to starch. This study reveals the dual effects of light on the sugar-fed C. zofingiensis and provides valuable insights into the possible optimization of algal biomass and lipid production by manipulation of culture conditions.

  16. Synergistic effects of oleaginous yeast Rhodotorula glutinis and microalga Chlorella vulgaris for enhancement of biomass and lipid yields.

    PubMed

    Zhang, Zhiping; Ji, Hairui; Gong, Guiping; Zhang, Xu; Tan, Tianwei

    2014-07-01

    The optimal mixed culture model of oleaginous yeast Rhodotorula glutinis and microalga Chlorella vulgaris was confirmed to enhance lipid production. A double system bubble column photo-bioreactor was designed and used for demonstrating the relationship of yeast and alga in mixed culture. The results showed that using the log-phase cultures of yeast and alga as seeds for mixed culture, the improvements of biomass and lipid yields reached 17.3% and 70.9%, respectively, compared with those of monocultures. Growth curves of two species were confirmed in the double system bubble column photo-bioreactor, and the second growth of yeast was observed during 36-48 h of mixed culture. Synergistic effects of two species for cell growth and lipid accumulation were demonstrated on O2/CO2 balance, substance exchange, dissolved oxygen and pH adjustment in mixed culture. This study provided a theoretical basis and culture model for producing lipids by mixed culture in place of monoculture. PMID:24841576

  17. Maximizing biomass productivity and cell density of Chlorella vulgaris by using light-emitting diode-based photobioreactor.

    PubMed

    Fu, Weiqi; Gudmundsson, Olafur; Feist, Adam M; Herjolfsson, Gisli; Brynjolfsson, Sigurdur; Palsson, Bernhard Ø

    2012-10-31

    Green microalgae have recently drawn attention as promising organisms for biofuel production; however, the question is whether they can grow sufficient biomass relative to limiting input factors to be economically feasible. We have explored this question by determining how much biomass the green microalga Chlorella vulgaris can produce in photobioreactors based on highly efficient light-emitting diodes (LEDs). First, growth results were improved under the less expensive light of 660 nm LEDs, developing them in the laboratory to meet the performance levels of the traditional but more expensive 680 nm LEDs by adaptive laboratory evolution (ALE). We then optimized several other key parameters, including input superficial gas velocity, CO(2) concentration, light distribution, and growth media in reference to nutrient stoichiometry. Biomass density thereby rose to approximately 20 g dry-cell-weight (gDCW) per liter (L). Since the light supply was recognized as a limiting factor, illumination was augmented by optimization at systematic level, providing for a biomass productivity of up to 2.11 gDCW/L/day, with a light yield of 0.81 gDCW/Einstein. These figures, which represent the best results ever reported, point to new dimensions in the photoautotrophic performance of microalgal cultures.

  18. Improving carbohydrate production of Chlorella sorokiniana NIES-2168 through semi-continuous process coupled with mixotrophic cultivation.

    PubMed

    Wang, Yue; Chiu, Sheng-Yi; Ho, Shih-Hsin; Liu, Zhuo; Hasunuma, Tomohisa; Chang, Ting-Ting; Chang, Kuan-Fu; Chang, Jo-Shu; Ren, Nan-Qi; Kondo, Akihiko

    2016-08-01

    Biofuels from microalgae is now a hot issue of great potential. However, achieving high starch productivity with photoautotrophic microalgae is still challenging. A feasible approach to enhance the growth and target product of microalgae is to conduct mixotrophic cultivation. The appropriate acetate addition combined with CO2 supply as dual carbon sources (i.e., mixotrophic cultivation) could enhance the cell growth of some microalgae species, but the effect of acetate-mediated mixotrophic culture mode on carbohydrate accumulation in microalgae remains unclear. Moreover, there is still lack of the information concerning how to increase the productivity of carbohydrates from microalgae under acetate-amended mixotrophic cultivation and how to optimize the engineering strategies to achieve the goal. This study was undertaken to develop an optimal acetate-contained mixotrophic cultivation system coupled with effective operation strategies to markedly improve the carbohydrate productivity of Chlorella sorokiniana NIES-2168. The optimal carbohydrate productivity of 695 mg/L/d was obtained, which is the highest value ever reported. The monosaccharide in the accumulated carbohydrates is mainly glucose (i.e., 85-90%), which is very suitable for bio-alcohols fermentation. Hence, by applying the optimal process developed in this study, C. sorokiniana NIES-2168 has a high potential to serve as a feedstock for subsequent biofuels conversion. PMID:27312599

  19. Purifying synthetic high-strength wastewater by microalgae chlorella vulgaris under various light emitting diode wavelengths and intensities

    PubMed Central

    2013-01-01

    The high-strength wastewater is now well known as a threat to the natural water since it is highly possible to arouse water eutrophication or algal blooms. The effects of various light emitting diode wavelengths and intensities on the microalgae biological wastewater treatment system was studied in this research. The various nutrient removals and economic efficiencies represented similar variation trends, and these variations under both high C and N loading treatments were similar too. The order for microalgae C. vulgaris reproduction in terms of dry weight and nutrient removal efficiency both were red > white > yellow > blue, under high carbon and nitrogen loading treatments, indicating that the red light was the optimum light wavelength. Furthermore, considering the optimal light intensity in terms of nutrient removal efficiency was 2500 and 2000 μmol/m2•s, while in terms of economic efficiency was 1000, 1500 and 2000 μmol/m2•s. Therefore, the optimum light intensity was found to be 2000 μmol/m2•s. In addition, the optimal experimental illumination time was determined as 120 h. The Chlorella vulgaris microalgae biological wastewater treatment system utilized in this research was able to purify the high-strength carbon and nitrogen wastewater effectively under optimum light wavelength and intensity. PMID:24499586

  20. Algae-facilitated chemical phosphorus removal during high-density Chlorella emersonii cultivation in a membrane bioreactor.

    PubMed

    Xu, Meng; Bernards, Matthew; Hu, Zhiqiang

    2014-02-01

    An algae-based membrane bioreactor (A-MBR) was evaluated for high-density algae cultivation and phosphorus (P) removal. The A-MBR was seeded with Chlorella emersonii and operated at a hydraulic retention time of 1day with minimal biomass wastage for about 150days. The algae concentration increased from initially 385mg/L (or 315mg biomass COD/L) to a final of 4840mg/L (or 1664mg COD/L), yielding an average solids (algae biomass+minerals) production rate of 32.5gm(-3)d(-1) or 6.2gm(-2)d(-1). The A-MBR was able to remove 66±9% of the total P from the water while the algal biomass had an average of 7.5±0.2% extracellular P and 0.4% of intracellular P. The results suggest that algae-induced phosphate precipitation by algae is key to P removal and high-density algae cultivation produces P-rich algal biomass with excellent settling properties. PMID:24374248

  1. Biosynthesis of high yield fatty acids from Chlorella vulgaris NIES-227 under nitrogen starvation stress during heterotrophic cultivation.

    PubMed

    Shen, Xiao-Fei; Chu, Fei-Fei; Lam, Paul K S; Zeng, Raymond J

    2015-09-15

    In this study the heterotrophic cultivation of Chlorella vulgaris NIES-227 fed with glucose was investigated systematically using six media types; combinations of nitrogen repletion/depletion and phosphorus repletion/limitation/depletion. It was found that a high yield of fatty acids (0.88 of fed glucose-COD) and a high content of fatty acid methyl esters (FAMEs) (89% of dry weight) were obtained under nitrogen starved conditions. To our knowledge it is the first report on such high COD conversion yield and FAME content in microalgae. The dominant fatty acid (>50%) was methyl oleate (C18:1), a desirable component for biodiesel synthesis. FAME content under nitrogen starved conditions was significantly higher than under nitrogen sufficient conditions, while phosphorus had no significant influence, indicating that nitrogen starvation was the real "fatty acids trigger" in heterotrophic cultivation. These findings could simplify the downstream extraction process, such as the extrusion of oil from soybeans, and could reduce operating costs by improving the fatty acid yield from waste COD.

  2. Sensitivity and Antioxidant Response of Chlorella sp. MM3 to Used Engine Oil and Its Water Accommodated Fraction.

    PubMed

    Ramadass, Kavitha; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Naidu, Ravi

    2016-07-01

    We exposed the microalgal strain, Chlorella sp. MM3, to unused or used engine oil, or their water accommodated fractions (WAFs) to determine growth inhibition and response of antioxidant enzymes. Oil type and oil concentration greatly affected the microalgal growth. Used oil at 0.04 % (0.4 g L(-1)) resulted in 50 % inhibition in algal growth, measured in terms of chlorophyll-a, while the corresponding concentration of unused oil was nontoxic. Similarly, used oil WAF showed significant toxicity to the algal growth at 10 % level, whereas WAF from unused oil was nontoxic even at 100 % concentration. Peroxidase enzyme in the microalga significantly increased with used oil at concentrations above 0.04 g L(-1) whereas the induction of superoxide dismutase and catalase was apparent only at 0.06 g L(-1). Activities of the antioxidant enzymes increased significantly when the microalga was exposed to 75 and 100 % WAF obtained from used oil. The used oil toxicity on microalga could be due to the presence of toxic soluble mono- and polyaromatic compounds, heavy metals, and other compounds attained by the oil during its use in the motor engines.

  3. Bioethanol production from carbohydrate-enriched residual biomass obtained after lipid extraction of Chlorella sp. KR-1.

    PubMed

    Lee, Ok Kyung; Oh, You-Kwan; Lee, Eun Yeol

    2015-11-01

    The residual biomass of Chlorella sp. KR-1 obtained after lipid extraction was used for saccharification and bioethanol production. The carbohydrate was saccharified using simple enzymatic and chemical methods using Pectinex at pH 5.5 and 45°C and 0.3N HCl at 121°C for 15min with 76.9% and 98.2% yield, respectively, without any pretreatment. The residual biomass contained 49.7% carbohydrate consisting of 82.4% fermentable sugar and 17.6% non-fermentable sugar, which is valuable for bioethanol fermentation. Approximately 98.2% of the total carbohydrate was converted into monosaccharide (fermentable+non-fermentable sugar) using dilute acid saccharification. The fermentable sugar was subsequently fermented to bioethanol through separate hydrolysis and fermentation with a fermentation yield of 79.3%. Overall, 0.4g ethanol/g fermentable sugar and 0.16g ethanol/g residual biomass were produced. PMID:26218538

  4. A virus-encoded potassium ion channel is a structural protein in the chlorovirus Paramecium bursaria chlorella virus 1 virion

    PubMed Central

    Romani, Giulia; Piotrowski, Adrianna; Hillmer, Stefan; Gurnon, James; Van Etten, James L.; Moroni, Anna; Thiel, Gerhard

    2013-01-01

    Most chloroviruses encode small K+ channels, which are functional in electrophysiological assays. The experimental finding that initial steps in viral infection exhibit the same sensitivity to channel inhibitors as the viral K+ channels has led to the hypothesis that the channels are structural proteins located in the internal membrane of the virus particles. This hypothesis was questioned recently because proteomic studies failed to detect the channel protein in virions of the prototype chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1). Here, we used a mAb raised against the functional K+ channel from chlorovirus MA-1D to search for the viral K+ channel in the virus particle. The results showed that the antibody was specific and bound to the tetrameric channel on the extracellular side. The antibody reacted in a virus-specific manner with protein extracts from chloroviruses that encoded channels similar to that from MA-1D. There was no cross-reactivity with chloroviruses that encoded more diverse channels or with a chlorovirus that lacked a K+ channel gene. Together with electron microscopic imaging, which revealed labelling of individual virus particles with the channel antibody, these results establish that the viral particles contain an active K+ channel, presumably located in the lipid membrane that surrounds the DNA in the mature virions. PMID:23918407

  5. Synergistic effects of oleaginous yeast Rhodotorula glutinis and microalga Chlorella vulgaris for enhancement of biomass and lipid yields.

    PubMed

    Zhang, Zhiping; Ji, Hairui; Gong, Guiping; Zhang, Xu; Tan, Tianwei

    2014-07-01

    The optimal mixed culture model of oleaginous yeast Rhodotorula glutinis and microalga Chlorella vulgaris was confirmed to enhance lipid production. A double system bubble column photo-bioreactor was designed and used for demonstrating the relationship of yeast and alga in mixed culture. The results showed that using the log-phase cultures of yeast and alga as seeds for mixed culture, the improvements of biomass and lipid yields reached 17.3% and 70.9%, respectively, compared with those of monocultures. Growth curves of two species were confirmed in the double system bubble column photo-bioreactor, and the second growth of yeast was observed during 36-48 h of mixed culture. Synergistic effects of two species for cell growth and lipid accumulation were demonstrated on O2/CO2 balance, substance exchange, dissolved oxygen and pH adjustment in mixed culture. This study provided a theoretical basis and culture model for producing lipids by mixed culture in place of monoculture.

  6. Enhanced lipid accumulation and biodiesel production by oleaginous Chlorella protothecoides under a structured heterotrophic-iron (II) induction strategy.

    PubMed

    Li, Yuqin; Mu, Jinxiu; Chen, Di; Xu, Hua; Han, Fangxin

    2015-05-01

    A structured heterotrophic-iron (II) induction (HII) strategy was proposed to enhance lipid accumulation in oleaginous Chlorella protothecoides. C. protothecoides subjected to heterotrophic-iron (II) induction achieved a favorable lipid accumulation up to 62 % and a maximum lipid productivity of 820.17 mg/day, representing 2.78-fold and 3.64-fold increase respectively over heterotrophic cultivation alone. HII-induced cells produced significantly elevated levels of 16:0, 18:1(Δ9), and 18:2(Δ9,12) fatty acids (over 90 %). The lipid contents and plant lipid-like fatty acid compositions exhibit the potential of HII-induced C. protothecoides as biodiesel feedstock. Furthermore, 31 altered proteins in HII-induced algal cells were successfully identified. These differentially expressed proteins were assigned into nine molecular function categories, including carbohydrate metabolism, lipid biosynthesis, Calvin cycle, cellular respiration, photosynthesis, energy and transport, protein biosynthesis, regulate and defense, and unclassified. Analysis using the Kyoto encyclopedia of genes and genomes and gene ontology annotation showed that malic enzyme, acyltransferase, and ACP were key metabolic checkpoints found to modulate lipid accumulation in C. protothecoides. The results provided possible applications of HII cultivation strategy in other microalgal species and new possibilities in developing genetic and metabolic engineering microalgae for desirable lipid productivity.

  7. Effect of different organic matters on flocculation of Chlorella sorokiniana and optimization of flocculation conditions in swine manure wastewater.

    PubMed

    Zhang, Bo; Chen, Sanfeng

    2015-09-01

    In this study, flocculation of Chlorella sorokiniana cultivated in swine manure wastewater, BG-11 medium and BG-11 medium supplemented with different organic matters (glucose, urea and tryptone) was investigated. The results demonstrated that the minimum amount of Al(3+) required for complete flocculation in wastewater would increase substantially, and flocculation efficiency became highly sensitive to pH. Tryptone could cause similar extent of inhibition on flocculation as in wastewater. Meanwhile, glucose could increase concentrations of Algogenic Organic Matter (AOM), inhibiting flocculation strongly at higher pH, including flocculation induced by Al(3+) and autoflocculation. However, urea had little effect on flocculation of C. sorokiniana. Moreover, the major factors: dilution times, pH and flocculants dosage, which had significant impact on flocculation efficiency of C. sorokiniana in piggery wastewater, were optimized using response surface methodology (RSM). The optimal flocculation efficiency (100%) was achieved at pH 8.5, 7-folds of dilution and 52.14 mg L(-1) of Al(3+).

  8. Co-culturing Chlorella minutissima with Escherichia coli can increase neutral lipid production and improve biodiesel quality.

    PubMed

    Higgins, Brendan T; Labavitch, John M; VanderGheynst, Jean S

    2015-09-01

    Lipid productivity and fatty acid composition are important metrics for the production of high quality biodiesel from algae. Our previous results showed that co-culturing the green alga Chlorella minutissima with Escherichia coli under high-substrate mixotrophic conditions enhanced both culture growth and crude lipid content. To investigate further, we analyzed neutral lipid content and fatty acid content and composition of axenic cultures and co-cultures produced under autotrophic and mixotrophic conditions. We found that co-culturing C. minutissima with E. coli under high substrate conditions (10 g/L) increased neutral lipid content 1.9- to 3.1-fold and fatty acid content 1.5- to 2.6-fold compared to equivalent axenic C. minutissima cultures. These same co-cultures also exhibited a significant fatty acid shift away from trienoic and toward monoenoic fatty acids thereby improving the quality of the synthesized fatty acids for biodiesel production. Further investigation suggested that E. coli facilitates substrate uptake by the algae and that the resulting growth enhancement induces a nitrogen-limited condition. Enhanced carbon uptake coupled with nitrogen limitation is the likely cause of the observed neutral lipid accumulation and fatty acid profile changes.

  9. A hermetic self-sustained microbial solar cell based on Chlorella vulgaris and a versatile charge transfer chain

    NASA Astrophysics Data System (ADS)

    Pan, Keliang; Zhou, Peijiang

    2015-10-01

    A hermetic noble-metal-free membrane-less microbial solar cell (MSC) is established. The substances decomposition and regeneration in this MSC are carried out only by Chlorella vulgaris simultaneously. The conversion of metabolism types of C. vulgaris is controlled only by illumination. By using a pleiotropic redox mediator and a cupric hexacyanoferrate modified cathode, a two-phase three-stage charge transfer chain is formed. Through this pathway, the one microorganism self-sustained system gets a long-term power output up to 0.04773 mW/cm2 at 0.423 V without any material exchange with external, which is 50 times higher than that obtained from the original system. Benefiting from this electron buffer system, the battery will achieve an electricity generation in both light and dark conditions. There is almost no consumption of any substrates throughout the stabilized process, and no more additions are required. This maintenance-free and extremely inexpensive reactor with a simple structure and a long service life demonstrates the possibility of combining the microbial, chemical and photo cells.

  10. High yields of fatty acid and neutral lipid production from cassava bagasse hydrolysate (CBH) by heterotrophic Chlorella protothecoides.

    PubMed

    Chen, Junhui; Liu, Xiaoguang; Wei, Dong; Chen, Gu

    2015-09-01

    The fermentation process for high yields of fatty acid and neutral lipid production from cassava bagasse hydrolysate (CBH) was developed by heterotrophic Chlorella protothecoides. An efficient single-step enzymatic hydrolysis of cassava bagasse (CB) by cellulase was firstly developed to produce >30 g/L of reducing sugars. The concentrated CBH was subsequently applied in a batch culture, producing 7.9 g/L of dry biomass with yield of 0.44 g/g reducing sugar and 34.3 wt% of fatty acids and 48.6 wt% of neutral lipids. Furthermore, fed-batch fermentation using CBH achieved higher yields of fatty acids (41.0 wt% and a titer of 5.83 g/L) and neutral lipids (58.4 wt% and yield of 0.22 g/g reducing sugar). Additionally, the fatty acid profile analysis showed that the intercellular lipid was suitable to prepare high-quality biodiesel. This study demonstrated the feasibility of using CBH as low-cost feedstock to produce crude algal oil for sustainable biodiesel production.

  11. Nitrous Oxide (N2O) production in axenic Chlorella vulgaris microalgae cultures: evidence, putative pathways, and potential environmental impacts

    NASA Astrophysics Data System (ADS)

    Guieysse, B.; Plouviez, M.; Coilhac, M.; Cazali, L.

    2013-10-01

    Using antibiotic assays and genomic analysis, this study demonstrates nitrous oxide (N2O) is generated from axenic Chlorella vulgaris cultures. In batch assays, this production is magnified under conditions favouring intracellular nitrite accumulation, but repressed when nitrate reductase (NR) activity is inhibited. These observations suggest N2O formation in C. vulgaris might proceed via NR-mediated nitrite reduction into nitric oxide (NO) acting as N2O precursor via a pathway similar to N2O formation in bacterial denitrifiers, although NO reduction to N2O under oxia remains unproven in plant cells. Alternatively, NR may reduce nitrite to nitroxyl (HNO), the latter being known to dimerize to N2O under oxia. Regardless of the precursor considered, an NR-mediated nitrite reduction pathway provides a unifying explanation for correlations reported between N2O emissions from algae-based ecosystems and NR activity, nitrate concentration, nitrite concentration, and photosynthesis repression. Moreover, these results indicate microalgae-mediated N2O formation might significantly contribute to N2O emissions in algae-based ecosystems (e.g. 1.38-10.1 kg N2O-N ha-1 yr-1 in a 0.25 m deep raceway pond operated under Mediterranean climatic conditions). These findings have profound implications for the life cycle analysis of algae biotechnologies and our understanding of the global biogeochemical nitrogen cycle.

  12. Enhanced lipidic algae biomass production using gas transfer from a fermentative Rhodosporidium toruloides culture to an autotrophic Chlorella protothecoides culture.

    PubMed

    Santos, C A; Caldeira, M L; Lopes da Silva, T; Novais, J M; Reis, A

    2013-06-01

    In order to produce single-cell oil for biodiesel, a yeast and a microalga were, for the first time, grown in two separate reactors connected by their gas-phases, taking advantage of their complementary nutritional metabolisms, i.e., respiration and photosynthesis. The yeast Rhodosporidium toruloides was used for lipid production, originating a carbon dioxide-enriched outlet gas stream which in turn was used to stimulate the autotrophic growth of Chlorella protothecoides in a vertical-alveolar-panel (VAP) photobioreactor. The microalgal biomass productivity was 0.015 gL(-1)h(-1), and its lipid productivity attained 2.2 mgL(-1)h(-1) when aerated with the outlet gas stream from the yeast fermenter. These values represent an increase of 94% and 87%, respectively, as compared to a control culture aerated with air. The CO2 bio-fixed by the microalgal biomass reached an estimated value of 29 mgL(-1)h(-1) in the VAP receiving the gas stream from the fermenter, a value 1.9 times higher than that measured in the control VAP.

  13. Carotenoid and lipid production by the autotrophic microalga Chlorella protothecoides under nutritional, salinity, and luminosity stress conditions.

    PubMed

    Campenni', L; Nobre, B P; Santos, C A; Oliveira, A C; Aires-Barros, M R; Palavra, A M F; Gouveia, L

    2013-02-01

    Today microalgae represent a viable alternative source for high-value products. The specie Chlorella protothecoides (Cp), heterotrophically grown, has been widely studied and provides a high amount of lutein and fatty acids (FA) and has a good profile for biodiesel production. This work studies carotenoid and FA production by autotrophic grown Cp. Cp was grown until the medium's nitrogen was depleted, then diluted in NaCl solution, resulting in nutritional, luminosity, and salinity stresses. Different NaCl concentrations were tested (10, 20, 30 g/L) at two different dilutions. After dilution, a color shifting from green to orange-red was noticed, showing carotenoid production. The best production of both carotenoids and FA was attained with a 20 g/L NaCl solution. The total carotenoid content was 0.8 % w/w (canthaxanthin (23.3 %), echinenone (14.7 %), free astaxanthin (7.1 %), and lutein/zeaxanthin (4.1 %)). Furthermore, the total lipid content reached 43.4 % w/w, with a FA composition of C18:1 (33.64 %), C16:0 (23.30 %), C18:2 (11.53 %), and less than 12 % of C18:3, which is needed to fulfill the biodiesel quality specifications (EN 14214).

  14. Dual-mode cultivation of Chlorella protothecoides applying inter-reactors gas transfer improves microalgae biodiesel production.

    PubMed

    Santos, C A; Nobre, B; Lopes da Silva, T; Pinheiro, H M; Reis, A

    2014-08-20

    Chlorella protothecoides, a lipid-producing microalga, was grown heterotrophically and autotrophically in separate reactors, the off-gases exiting the former being used to aerate the latter. Autotrophic biomass productivity with the two-reactor association, 0.0249gL(-1)h(-1), was 2.2-fold the value obtained in a control autotrophic culture, aerated with ambient air. Fatty acid productivity was 1.7-fold the control value. C. protothecoides heterotrophic biomass productivity was 0.229gL(-1)h(-1). This biomass' fatty acid content was 34.5% (w/w) with a profile suitable for biodiesel production, according to European Standards. The carbon dioxide fixed by the autotrophic biomass was 45mgCO2L(-1)h(-1) in the symbiotic arrangement, 2.1 times the control reactor value. The avoided CO2 atmospheric emission represented 30% of the CO2 produced in the heterotrophic stage, while the released O2 represented 49% of the oxygen demand in that stage. Thus, an increased efficiency in the glucose carbon source use and a higher environmental sustainability were achieved in microalgal biodiesel production using the proposed assembly.

  15. Affinity Purification of O-Acetylserine(thiol)lyase from Chlorella sorokiniana by Recombinant Proteins from Arabidopsis thaliana.

    PubMed

    Salbitani, Giovanna; Wirtz, Markus; Hell, Rüdiger; Carfagna, Simona

    2014-01-01

    In the unicellular green alga Chlorella sorokiniana (211/8 k), the protein O-acetylserine(thiol)lyase (OASTL), representing the key-enzyme in the biosynthetic cysteine pathway, was isolated and purified to apparent homogeneity. The purification was carried out in cells grown in the presence of all nutrients or in sulphate (S) deprived cells. After 24 h of S-starvation, a 17-fold increase in the specific activity of OASTL was measured. In order to enable the identification of OASTL proteins from non-model organisms such as C. sorokiniana, the recombinant his-tagged SAT5 protein from Arabidopsis thaliana was immobilized by metal chelate chromatography. OASTL proteins from C. sorokiniana were affinity purified in one step and activities were enhanced 29- and 41-fold, from S-sufficient and S-starved (24 h) cells, respectively. The successful application of SAT/OASTL interaction for purification confirms for the first time the existence of the cysteine synthase complexes in microalgae. The purified proteins have apparent molecular masses between 32-34 kDa and are thus slightly larger compared to those found in Arabidopsis thaliana and other vascular plants. The enhanced OASTL activity in S-starved cells can be attributed to increased amounts of plastidic and the emergence of cytosolic OASTL isoforms. The results provide proof-of-concept for the biochemical analysis of the cysteine synthase complex in diverse microalgal species. PMID:25093930

  16. Utilization of simulated flue gas containing CO2, SO2, NO and ash for Chlorella fusca cultivation.

    PubMed

    Duarte, Jessica Hartwig; Fanka, Letícia Schneider; Costa, Jorge Alberto Vieira

    2016-08-01

    Microalgae can use the CO2 from coal power plants in their metabolic pathways. However, these microorganisms must be able to tolerate other residues produced from burning coal. This study evaluated the wastes addition (CO2, SO2, NO and ash) present in the flue gas from a coal power plant on the growth parameters during culture, CO2 biofixation and on the biomass characterization of Chlorella fusca LEB 111. The SO2 and NO injection (until 400ppm) in cultivations did not markedly affect CO2 biofixation by microalga. The best CO2 biofixation efficiency was obtained with 10% CO2, 200ppm SO2 and NO and 40ppm ash (50.0±0.8%, w w(-1)), showing a specific growth rate of 0.18±0.01 d(-1). The C. fusca LEB 111 biomass composition was similar in all experiments with around 19.7% (w w(-1)) carbohydrates, 15.5% (w w(-1)) lipids and 50.2% (w w(-1)) proteins. PMID:27132223

  17. Cultivation of Chlorella vulgaris and Arthrospira platensis with Recovered Phosphorus from Wastewater by Means of Zeolite Sorption

    PubMed Central

    Markou, Giorgos; Depraetere, Orily; Vandamme, Dries; Muylaert, Koenraad

    2015-01-01

    In this study, zeolite was employed for the separation and recovery of P from synthetic wastewater and its use as phosphorus (P) source for the cultivation of the green microalga Chlorella vulgaris and the cyanobacterium Arthrospira (Spirulina) platensis. At P-loaded zeolite concentration of 0.15–1 g/L, in which P was limited, the two species displayed quite different behavior regarding their growth and biomass composition. C. vulgaris preferred to increase the intracellular P and did not synthesize biomass, while A. platensis synthesized biomass keeping the intracellular P as low as possible. In addition under P limitation, C. vulgaris did display some little alteration of the biomass composition, while A. platensis did it significantly, accumulating carbohydrates around 70% from about 15%–20% (control). Both species could desorb P from zeolite biologically. A. platensis could recover over 65% and C. vulgaris 25% of the P bounded onto zeolite. When P-loaded zeolite concentration increased to 5 g/L, P was adequate to support growth for both species. Especially in the case of C. vulgaris, growth was stimulated from the presence of P-loaded zeolite and produced more biomass compared to the control. PMID:25690037

  18. Toxicity of Cu (II) to the green alga Chlorella vulgaris: a perspective of photosynthesis and oxidant stress.

    PubMed

    Chen, Zunwei; Song, Shufang; Wen, Yuezhong; Zou, Yuqin; Liu, Huijun

    2016-09-01

    The toxic effects of Cu (II) on the freshwater green algae Chlorella vulgaris and its chloroplast were investigated by detecting the responses of photosynthesis and oxidant stress. The results showed that Cu (II) arrested the growth of C. vulgaris and presented in a concentration- and time-dependent trend and the SRichards 2 model fitted the inhibition curve best. The chlorophyll fluorescence parameters, including qP, Y (II), ETR, F v /F m , and F v /F 0, were stimulated at low concentration of Cu (II) but declined at high concentration, indicating the photosystem II (PSII) of C. vulgaris was destroyed by Cu (II). The chloroplasts were extracted, and the Hill reaction activity (HRA) of chloroplast was significantly decreased with the increasing Cu (II) concentration under both illuminating and dark condition, and faster decline speed was observed under dark condition. Activities of superoxide dismutase (SOD) and catalase (CAT) and malondialdehyde (MDA) content were also significantly decreased at high concentration Cu (II), companied with a large number of reactive oxygen species (ROS) production. All these results indicated a severe oxidative stress on algal cells occurred as well as the effect on photosynthesis, thus inhibiting the growth of algae, which providing sights to evaluate the phytotoxicity of Cu (II). PMID:27255311

  19. Elucidation of the defence mechanism in microalgae Chlorella sorokiniana under mercury exposure. Identification of Hg-phytochelatins.

    PubMed

    Gómez-Jacinto, Verónica; García-Barrera, Tamara; Gómez-Ariza, José Luis; Garbayo-Nores, Inés; Vílchez-Lobato, Carlos

    2015-08-01

    Algae and aquatic macrophytes are capable of accumulating heavy metals up to concentrations several orders of magnitude higher than those existing in their surrounding environment. Investigation of mercury toxicology in microalgae is of great interest from ecological point of view, since they could be used as bioindicator to evaluate aquatic ecosystems affected by Hg pollution. In this study, we have performed an exposure experiment focused on the biological response of microalgae Chlorella sorokiniana, a unicellular model organism, to Hg-induced toxicity. The culture was exposed to different concentrations of this element for nine days, namely 0.5, 1, 5 and 10mg L(-1) of HgCl2 (as Hg). To achieve a better understanding of the biological mechanisms triggered by Hg-induced toxicity in this alga a metallomic approach based on SEC-ICP-ORS-MS was applied to survey biomarkers of biological response to mercury contamination in surface water. In addition, the combination of RP-HPLC-ICP-ORS-MS and RP-HPLC-ESI-QqQ-TOF-MS was applied to identify, for the first time, two Hg-binding phytochelatins in this aquatic organism, using cell extracts from microalgae exposed to inorganic mercury. PMID:26079052

  20. Cultivation of Chlorella vulgaris JSC-6 with swine wastewater for simultaneous nutrient/COD removal and carbohydrate production.

    PubMed

    Wang, Yue; Guo, Wanqian; Yen, Hong-Wei; Ho, Shih-Hsin; Lo, Yung-Chung; Cheng, Chieh-Lun; Ren, Nanqi; Chang, Jo-Shu

    2015-12-01

    Swine wastewater, containing a high concentration of COD and ammonia nitrogen, is suitable for the growth of microalgae, leading to simultaneous COD/nutrients removal from the wastewater. In this study, an isolated carbohydrate-rich microalga Chlorella vulgaris JSC-6 was adopted to perform swine wastewater treatment. Nearly 60-70% COD removal and 40-90% NH3-N removal was achieved in the mixotrophic and heterotrophic culture, depending on the dilution ratio of the wastewater, while the highest removal percentage was obtained with 20-fold diluted wastewater. Mixotrophic cultivation by using fivefold diluted wastewater resulted in the highest biomass concentration of 3.96 g/L. The carbohydrate content of the microalga grown on the wastewater can reach up to 58% (per dry weight). The results indicated that the microalgae-based wastewater treatment can efficiently reduce the nutrients and COD level, and the resulting microalgal biomass had high carbohydrate content, thereby having potential applications for the fermentative production of biofuels or chemicals. PMID:26433786