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Sample records for algae chlorella sp

  1. Cultivation of Monoraphidium sp., Chlorella sp. and Scenedesmus sp. algae in Batch culture using Nile tilapia effluent.

    PubMed

    Guerrero-Cabrera, Luis; Rueda, José A; García-Lozano, Hiram; Navarro, A Karin

    2014-06-01

    Monoraphidium sp., Chlorella sp. and Scenedesmus sp. algae were cultured in three volumes of Tilapia Effluent Medium (TEM) in comparison with the Bold Basal Medium (BBM) (Nichols and Bold, 1965). Specific growth rate (μ'), biomass dry productivity (Q), volumetric productivity (Qv) as well as lipid and protein content were measured. Then, volumetric productivities for both lipids and proteins were calculated (QVL and QVP). In Scenedesmus sp., BBM produced higher μ' and Qv than TEM in 1.5L volume. Chlorella sp. showed a higher QVL for BBM than TEM. Any observed difference in protein or lipid productivities among volumes was in favor of a greater productivity for 1.5L volume. Even when TEM had a larger protein content in Chlorella sp. than BBM, QVP was not different. Current results imply that TEM can be used as an alternative growth medium for algae when using Batch cultures, yet productivity is reduced. PMID:24736090

  2. 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

  3. First Report of Pseudobodo sp, a New Pathogen for a Potential Energy-Producing Algae: Chlorella vulgaris Cultures

    PubMed Central

    Zhang, Bangzhou; Yang, Luxi; Zhang, Huajun; Zhang, Jingyan; Li, Yi; Zheng, Wei; Tian, Yun; Liu, Jingwen; Zheng, Tianling

    2014-01-01

    Chlorella vulgaris, is a kind of single-celled green algae, which could serve as a potential source of food and energy because of its photosynthetic efficiency. In our study, a pathogenic organism targeting C. vulgaris was discovered. The algae-lytic activity relates to a fraction from lysates of infected C. vulgaris that was blocked upon filtration through a 3 µm filter. 18S rRNA gene sequence analysis revealed that it shared 99.0% homology with the protist Pseudobodo tremulans. Scanning electron microscope analysis showed that Pseudobodo sp. KD51 cells were approximately 4–5 µm long, biflagellate with an anterior collar around the anterior part of the cell in unstressed feeding cells. Besides the initial host, Pseudobodo sp. KD51 could also kill other algae, indicating its relatively wide predatory spectrum. Heat stability, pH and salinity tolerance experiments were conducted to understand their effects on its predatory activities, and the results showed that Pseudobodo sp. KD51 was heat-sensitive, and pH and salinity tolerant. PMID:24599263

  4. First report of Pseudobodo sp, a new pathogen for a potential energy-producing algae: Chlorella vulgaris cultures.

    PubMed

    Chen, Zhangran; Lei, Xueqian; Zhang, Bangzhou; Yang, Luxi; Zhang, Huajun; Zhang, Jingyan; Li, Yi; Zheng, Wei; Tian, Yun; Liu, Jingwen; Zheng, Tianling

    2014-01-01

    Chlorella vulgaris, is a kind of single-celled green algae, which could serve as a potential source of food and energy because of its photosynthetic efficiency. In our study, a pathogenic organism targeting C. vulgaris was discovered. The algae-lytic activity relates to a fraction from lysates of infected C. vulgaris that was blocked upon filtration through a 3 µm filter. 18S rRNA gene sequence analysis revealed that it shared 99.0% homology with the protist Pseudobodo tremulans. Scanning electron microscope analysis showed that Pseudobodo sp. KD51 cells were approximately 4-5 µm long, biflagellate with an anterior collar around the anterior part of the cell in unstressed feeding cells. Besides the initial host, Pseudobodo sp. KD51 could also kill other algae, indicating its relatively wide predatory spectrum. Heat stability, pH and salinity tolerance experiments were conducted to understand their effects on its predatory activities, and the results showed that Pseudobodo sp. KD51 was heat-sensitive, and pH and salinity tolerant. PMID:24599263

  5. Combined biocidal action of silver nanoparticles and ions against Chlorococcales (Scenedesmus quadricauda, Chlorella vulgaris) and filamentous algae (Klebsormidium sp.).

    PubMed

    Zouzelka, Radek; Cihakova, Pavlina; Rihova Ambrozova, Jana; Rathousky, Jiri

    2016-05-01

    Despite the extensive research, the mechanism of the antimicrobial and biocidal performance of silver nanoparticles has not been unequivocally elucidated yet. Our study was aimed at the investigation of the ability of silver nanoparticles to suppress the growth of three types of algae colonizing the wetted surfaces or submerged objects and the mechanism of their action. Silver nanoparticles exhibited a substantial toxicity towards Chlorococcales Scenedesmus quadricauda, Chlorella vulgaris, and filamentous algae Klebsormidium sp., which correlated with their particle size. The particles had very good stability against agglomeration even in the presence of multivalent cations. The concentration of silver ions in equilibrium with nanoparticles markedly depended on the particle size, achieving about 6 % and as low as about 0.1 % or even less for the particles 5 nm in size and for larger ones (40-70 nm), respectively. Even very limited proportion of small particles together with larger ones could substantially increase concentration of Ag ions in solution. The highest toxicity was found for the 5-nm-sized particles, being the smallest ones in this study. Their toxicity was even higher than that of silver ions at the same silver concentration. When compared as a function of the Ag(+) concentration in equilibrium with 5-nm particles, the toxicity of ions was at least 17 times higher than that obtained by dissolving silver nitrite (if not taking into account the effect of nanoparticles themselves). The mechanism of the toxicity of silver nanoparticles was found complex with an important role played by the adsorption of silver nanoparticles and the ions released from the particles on the cell surface. This mechanism could be described as some sort of synergy between nanoparticles and ions. While our study clearly showed the presence of this synergy, its detailed explanation is experimentally highly demanding, requiring a close cooperation between materials scientists

  6. Evaluation of an oil-producing green alga Chlorella sp. C2 for biological DeNOx of industrial flue gases.

    PubMed

    Zhang, Xin; Chen, Hui; Chen, Weixian; Qiao, Yaqin; He, Chenliu; Wang, Qiang

    2014-09-01

    NOx, a significant portion of fossil fuel flue gases, are among the most serious environmental issues in the world and must be removed in an additional costly gas treatment step. This study evaluated the growth of the green alga Chlorella sp. C2 under a nitrite-simulated NOx environment and the removal rates of actual flue gas fixed salts (FGFSs) from Sinopec's Shijiazhuang refinery along with lipid production. The results showed that nitrite levels lower than 176.5 mM had no significant adverse effects on the cell growth and photosynthesis of Chlorella sp. C2, demonstrating that this green alga could utilize nitrite and NOx as a nitrogen source. High concentrations of nitrite (88.25-176.5 mM) also resulted in the accumulation of neutral lipids. A 60% nitrite removal efficiency was obtained together with the production of 33% algae lipids when cultured with FGFS. Notably, the presence of nitrate in the FGFS medium significantly enhanced the nitrite removal capability, biomass and lipid production. Thus, this study may provide a new insight into the economically viable application of microalgae in the synergistic combination of biological DeNOx of industrial flue gases and biodiesel production. PMID:25105531

  7. Effective Biological DeNOx of Industrial Flue Gas by the Mixotrophic Cultivation of an Oil-Producing Green Alga Chlorella sp. C2.

    PubMed

    Chen, Weixian; Zhang, Shanshan; Rong, Junfeng; Li, Xiang; Chen, Hui; He, Chenliu; Wang, Qiang

    2016-02-01

    Nitrogen oxides (NOx) are the components of fossil flue gas that result in the most serious environmental concerns. We previously showed that the biological removal of NOx by microalgae appears superior to traditional treatments. This study optimizes the strategy for the microalgal-based DeNOx of flue gas by fed-batch mixotrophic cultivation. By using actual flue gas fixed salts (FGFS) as the nitrogen supply, the mixotrophical cultivation of the green alga Chlorella sp. C2 with high NOx absorption efficiency was optimized in a stepwise manner in a 5 L bioreactor and resulted in a maximum biomass productivity of 9.87 g L(-1) d(-1). The optimized strategy was further scaled up to 50 L, and a biomass productivity of 7.93 g L(-1) d(-1) was achieved, with an overall DeNOx efficiency of 96%, along with an average nitrogen CR of 0.45 g L(-1) d(-1) and lipid productivity of 1.83 g L(-1) d(-1). With an optimized mixotrophical cultivation, this study further proved the feasibility of using Chlorella for the combination of efficient biological DeNOx of flue gas and microalgae-based products production. Thus, this study shows a promising industrial strategy for flue gas biotreatment in plants with limited land area. PMID:26751001

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

    PubMed

    Morgan-Kiss, Rachael M; Ivanov, Alexander G; Modla, Shannon; Czymmek, Kirk; Hüner, Norman P A; Priscu, John C; Lisle, John T; Hanson, Thomas E

    2008-09-01

    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 degrees 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. PMID:18661097

  9. 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.

  10. CO2 Biofixation by the Cyanobacterium Spirulina sp. LEB 18 and the Green Alga Chlorella fusca LEB 111 Grown Using Gas Effluents and Solid Residues of Thermoelectric Origin.

    PubMed

    da Silva Vaz, Bruna; Costa, Jorge Alberto Vieira; de Morais, Michele Greque

    2016-01-01

    The concentration of carbon dioxide (CO2) in the atmosphere has increased from 280 to 400 ppm in the last 10 years, and the coal-fired power plants are responsible for approximately 22 % of these emissions. The burning of fossil fuel also produces a great amount of solid waste that causes serious industrial and environmental problems. The biological processes become interesting alternative in combating pollution and developing new products. The objective of this study was to evaluate the CO2 biofixation potential of microalgae that were grown using gaseous effluents and solid residues of thermoelectric origin. The microalgae Chlorella fusca LEB 111 presented higher rate of CO2 biofixation (42.8 %) (p < 0.01) than did Spirulina sp. LEB 18. The values for the CO2 biofixation rates and the kinetic parameters of Spirulina and Chlorella cells grown using combustion gas did not differ significantly from those of cells grown using CO2 and a carbon source in the culture media. These microalgae could be grown using ash derived from coal combustion, using the minerals present in this residue as the source of the essential metals required for their growth and the CO2 derived from the combustion gas as their carbon source. PMID:26453033

  11. 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.

  12. The influence of hypergravity on the Paramecium bursaria-Chlorella sp. symbiotic association.

    PubMed

    Bator, Tomasz; Pado, Ryszard

    2009-01-01

    The aim of the research was to determine the influence of strong hypergravity on the Paramecium bursaria-Chlorella sp. symbiotic association, which is considered to be a model example of symbiosis between a heterotroph and an autotroph. The paramecia cells were exposed to 1073 x g, 4293 x g, and 9658 x g hypergravity for 15 min. Then they were incubated for 21 d on a standard lettuce medium. The experiments were conducted in parallel under constant white light and in the dark. The changes in the number of paramecia cells during incubation were determined. Measurements of the number of Chlorella sp. endosymbionts inside host cells were also made. The results showed that a 15-min exposure to hypergravity attenuates the subsequent growth of Paramecium bursaria in the dark, but it may stimulate the growth of paramecia under constant light. Moreover, it causes an increase in the number of algae inside the paramecia cells. Presumably, the influence of hypergravity on the studied symbiotic complex is connected with its effect on the endosymbiotic Chlorella sp. cells. This subject requires further research, focused on the influence of hypergravity on the physiology and growth of the Chlorella sp. endosymbionts living inside the Paramecium bursaria cells. PMID:19957445

  13. 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+

  14. Effects of tetrabromobisphenol A on the green alga Chlorella pyrenoidosa.

    PubMed

    Liu, Hongling; Yu, Yang; Kong, Fanxiang; He, Luning; Yu, Hongxia; Giesy, John P; Wang, Xiaorong

    2008-09-01

    Flow cytometry (FC) was used to determine effects of tetrabromobisphenol A (TBBPA) on the green alga Chlorella pyrenoidosa (C. pyrenoidosa) by evaluating esterase activity, membrane integrity, concentrations of intracellular reactive oxygen species (ROS) and chlorophyll a (Chl-a) auto-fluorescence. TBBPA can inhibit esterase activity. Esterase activity was inversely proportional with TBBPA with a 24 h EC(50) value of 3.13 mg TBBPA/L. After 48 h of exposure to TBBPA intracellular ROS was significantly greater than in the unexposed cells. TBBPA inhibited Chl-a fluorescence after 168 h. Concentrations of ROS were directly proportional to both magnitude and duration of exposure and was inversely proportional to cellular Chl-a. FC was useful as an integrated, ecologically relevant, measure of a functional response of the algae. The possible action pathway of TBBPA in C. pyrenoidosa is that TBBPA can cause toxic effects on esterase activity. As concentrations and exposure time increased, TBBPA change the ROS level in the internal. The role of anti-oxidative action is marked and significant at the duration of 48 h exposure, compared to the control. This suggested there was a redox cycle. TBBPA changes physiological status of cells, further decreased Chl-a fluorescence indicating inhibition. PMID:18642150

  15. 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. PMID:20522192

  16. Ammonium reduces chromium toxicity in the freshwater alga Chlorella vulgaris.

    PubMed

    Liu, Jingqing; Sun, Zhengqi; Lavoie, Michel; Fan, Xiaoji; Bai, Xiaocui; Qian, Haifeng

    2015-04-01

    The aim of the present study was to investigate the protective effect of ammonium (NH4 (+)) on Cr toxicity to the freshwater alga Chlorella vulgaris. We followed an array of cellular functions and biomolecules in C. vulgaris cells exposed to 50 or 100 μM Cr at three different initial NH4 (+) concentrations (0.5, 3, and 10 mM). The results showed that Cr strongly inhibited cell yield of C. vulgaris, but 10 mM NH4 (+) could decrease by more than two-fold Cr toxicity on cell yield compared to exposure to 0.5 mM NH4 (+). Cr toxicity on gene transcripts and cellular substructure was also much lower at high than at low NH4 (+). Our results suggest that this protecting effect of NH4 (+) on intracellular Cr toxicity could be due to several factors, such as enhance uptake of phosphorus, increase in C and N assimilation efficiency, and increase transcription of photosynthesis-related genes. PMID:25421561

  17. 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.

  18. 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

  19. 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

  20. 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

  1. Growing Chlorella sp. on meat processing wastewater for nutrient removal and biomass production.

    PubMed

    Lu, Qian; Zhou, Wenguang; Min, Min; Ma, Xiaochen; Chandra, Ceria; Doan, Yen T T; Ma, Yiwei; Zheng, Hongli; Cheng, Sibo; Griffith, Richard; Chen, Paul; Chen, Chi; Urriola, Pedro E; Shurson, Gerald C; Gislerød, Hans R; Ruan, Roger

    2015-12-01

    In this work, Chlorella sp. (UM6151) was selected to treat meat processing wastewater for nutrient removal and biomass production. To balance the nutrient profile and improve biomass yield at low cost, an innovative algae cultivation model based on wastewater mixing was developed. The result showed that biomass yield (0.675-1.538 g/L) of algae grown on mixed wastewater was much higher than that on individual wastewater and artificial medium. Wastewater mixing eased the bottleneck for algae growth and contributed to the improved biomass yield. Furthermore, in mixed wastewater with sufficient nitrogen, ammonia nitrogen removal efficiencies (68.75-90.38%) and total nitrogen removal efficiencies (30.06-50.94%) were improved. Wastewater mixing also promoted the synthesis of protein in algal cells. Protein content of algae growing on mixed wastewater reached 60.87-68.65%, which is much higher than that of traditional protein source. Algae cultivation model based on wastewater mixing is an efficient and economical way to improve biomass yield. PMID:26386422

  2. 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

  3. 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

  4. Photoreduction of chromium(VI) in the presence of algae, Chlorella vulgaris.

    PubMed

    Deng, Lin; Wang, Hongli; Deng, Nansheng

    2006-11-16

    In this thesis, the photochemical reduction of hexavalent chromium Cr(VI) in the presence of algae, Chlorella vulgaris, was investigated under the irradiation of metal halide lamps (lambda = 365 nm, 250 W). The affecting factors of photochemical reduction were studied in detail, such as exposure time, initial Cr(VI) concentration, initial algae concentration and pH. The rate of Cr(VI) photochemical reduction increased with algae concentration increasing, exposure time increasing, initial Cr(VI) concentration decreasing and the decrease of pH. When pH increased to 6, the rate of Cr(VI) photochemical reduction nearly vanished. When initial Cr(VI) concentration ranged from 0.4 to 1.0 mg L(-1) and initial algae concentration ranged from ABS(algae) (the absorbency of algae) = 0.025 to ABS(algae) = 0.180, According to the results of kinetic analyses, the kinetic equation of Cr(VI) photochemical reduction in aqueous solution with algae under 250 W metal halide lamps was V0 = kC(0)(0.1718)A(algae)(0.5235) (C0 was initial concentration of Cr(VI); A(algae) was initial concentration of algae) under the condition of pH 4. PMID:16839665

  5. 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

  6. RESPONSES OF MARINE UNICELLULAR ALGAE TO BROMINATED ORGANIC COMPOUNDS IN SIX GROWTH MEDIA

    EPA Science Inventory

    Marine unicellular algae, Skeletonema costatum, Thalassiosira pseudonana, and Chlorella sp., were exposed to the industrial brominated compounds, tetrabromobisphenol A (TBBP), decabromobiphenyloxide (DBBO), hexabromocyclododecane (HBCD), pentabromomethylbenzene (PBMB), pentabromo...

  7. 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. PMID:26935773

  8. 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

  9. Mychonastes desiccatus Brown sp. nova (Chlorococcales, Chlorophyta)--an intertidal alga forming achlorophyllous desiccation-resistant cysts

    NASA Technical Reports Server (NTRS)

    Margulis, L.; Hinkle, G.; McKhann, H.; Moynihan, B.

    1988-01-01

    An intertidal Chlorella-like alga Mychonastes desiccatus Brown sp. nova, capable of forming achlorophyllous desiccation-resistant cysts, has been grown in unialgal culture. This small alga was first isolated from a dried sample of a well-studied microbial mat. The mat, located at North Pond, Laguna Figueroa, San Quintin, Baja California, Mexico, is a vertically-stratified microbial community which forms laminated sediments. Morphology, pigment composition and G+C content are within the range typical for the genus Chlorella s. 1. Unlike other chlorellae, however, upon desiccation M. desiccatus forms an achlorophyllous, lipid-filled cyst (thick-walled resting stage) in which no plastid is evident. Rewetting leads to chloroplast differentiation, excystment and recovery of the fully green alga. During desiccation, sporopollenin is deposited within a thickening cell wall. Encystment cannot be induced by growth in the dark. The formation of desiccation-induced cysts allows the alga to survive frequent and intermittent periods of dryness. These chlorellae tolerate wide ranges of acidity and temperature; they both grow and form cysts in media in which sodium ions are replaced with potassium. Although the cysts tolerate crystalline salts, the cell grow optimally in concentrations corresponding from three-quarters to full-strength seawater.

  10. 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.

  11. 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

  12. 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

  13. Chlorella minutissima--a promising fuel alga for cultivation in municipal wastewaters.

    PubMed

    Bhatnagar, Ashish; Bhatnagar, Monica; Chinnasamy, Senthil; Das, K C

    2010-05-01

    It is imperative to slash the cost of algal oil to less than $50 bbl(-1) for successful algal biofuel production. Use of municipal wastewater for algal cultivation could obviate the need for freshwater and the nutrients--N and P. It would also add CO2 through bacterial activity. Chlorella minutissima Fott et Nova dominated the entire phycoflora year around and through each stage of the wastewater treatment at the oxidation pond system of Wazirabad (Delhi) in India. The ability to grow so profusely in such varied and contrasting situations made this alga unique. Besides pollution tolerance, it grew heterotrophically in dark under acidic conditions and as a mixotroph in presence of light over a range of organic C substrates. It could utilize both ammoniacal and nitrate nitrogen, survived anaerobicity, 5% NaCl and-10 bar of osmotic stress. C. minutissima grew at pH 4-11 and raised the pH set initially by 1 to 3 units in 7.5 h. It showed gigantism and largely kept afloat in presence of utilizable organic carbon, while flocculated in mineral medium and on aging. The alga also possessed potential for biofuel production. The studied parameters indicate why C. minutissima was a potential biomass builder in municipal sewage and could be used to determine which other alga(e) may serve the purpose. PMID:19882116

  14. 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.

  15. Size-dependent ecotoxicity of barium titanate particles: the case of Chlorella vulgaris green algae.

    PubMed

    Polonini, Hudson C; Brandão, Humberto M; Raposo, Nádia R B; Brandão, Marcos Antônio F; Mouton, Ludovic; Couté, Alain; Yéprémian, Claude; Sivry, Yann; Brayner, Roberta

    2015-05-01

    Studies have been demonstrating that smaller particles can lead to unexpected and diverse ecotoxicological effects when compared to those caused by the bulk material. In this study, the chemical composition, size and shape, state of dispersion, and surface's charge, area and physicochemistry of micro (BT MP) and nano barium titanate (BT NP) were determined. Green algae Chlorella vulgaris grown in Bold's Basal (BB) medium or Seine River water (SRW) was used as biological indicator to assess their aquatic toxicology. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic activity were evaluated. Tetragonal BT (~170 nm, 3.24 m(2) g(-1) surface area) and cubic BT (~60 nm, 16.60 m(2) g(-1)) particles were negative, poorly dispersed, and readily aggregated. BT has a statistically significant effect on C. vulgaris growth since the lower concentration tested (1 ppm), what seems to be mediated by induced oxidative stress caused by the particles (increased SOD activity and decreased photosynthetic efficiency and intracellular ATP content). The toxic effects were more pronounced when the algae was grown in SRW. Size does not seem to be an issue influencing the toxicity in BT particles toxicity since micro- and nano-particles produced significant effects on algae growth. PMID:25763523

  16. Luxury uptake of phosphorus changes the accumulation of starch and lipid in Chlorella sp. under nitrogen depletion.

    PubMed

    Zhu, Shunni; Wang, Yajie; Xu, Jin; Shang, Changhua; Wang, Zhongming; Xu, Jingliang; Yuan, Zhenhong

    2015-12-01

    The aim of this research was to study the effect of phosphorus supply on starch and lipid production under nitrogen starvation using Chlorella sp. as a model. High phosphate level had marginal effect on cell density but increased biomass growth. Massive phosphorus was assimilated quickly and mainly stored in the form of polyphosphate. The algal cells ceased phosphorus uptake when intracellular phosphorus reached a certain level. 5mM phosphate in the culture rendered a 16.7% decrease of starch synthesis and a 22.4% increase of lipid synthesis relative to low phosphate (0.17 mM). It is plausible that phosphate can regulate carbon partitioning between starch and lipid synthesis pathway by influencing ADP-glucose pyrophosphorylase activity. Moreover, high phosphate concentration enhanced the abundance of oleic acid, improving oil quality for biodiesel production. It is a promising cultivation strategy by integration of phosphorus removal from wastewater with biodiesel production for this alga. PMID:26386419

  17. 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.

  18. Anaerobic digested dairy manure as a nutrient supplement for cultivation of oil-rich green microalgae Chlorella sp.

    PubMed

    Wang, Liang; Li, Yecong; Chen, Paul; Min, Min; Chen, Yifeng; Zhu, Jun; Ruan, Roger R

    2010-04-01

    The present study was to investigate the effectiveness of using digested dairy manure as a nutrient supplement for cultivation of oil-rich green microalgae Chlorella sp. Different dilution multiples of 10, 15, 20, and 25 were applied to the digested manure and algal growth was compared in regard to growth rate, nutrient removal efficiency, and final algal fatty acids content and composition. Slower growth rates were observed with less diluted manure samples with higher turbidities in the initial cultivation days. A reverse linear relationship (R(2) = 0.982) was found between the average specific growth rate of the beginning 7 days and the initial turbidities. Algae removed ammonia, total nitrogen, total phosphorus, and COD by 100%, 75.7-82.5%, 62.5-74.7%, and 27.4-38.4%, respectively, in differently diluted dairy manure. COD in digested dairy manure, beside CO(2), proved to be another carbon source for mixotrophic Chlorella. Fatty acid profiles derived from triacylglyceride (TAG), phospholipid and free fatty acids showed that octadecadienoic acid (C18:2) and hexadecanoic acid (C16:0) were the two most abundant fatty acids in the algae. The total fatty acid content of the dry weight increased from 9.00% to 13.7% along with the increasing dilution multiples. Based on the results from this study, a process combining anaerobic digestion and algae cultivation can be proposed as an effective way to convert high strength dairy manure into profitable byproducts as well as to reduce contaminations to environment. PMID:19932957

  19. Symbiotic ciliates receive protection against UV damage from their algae: a test with Paramecium bursaria and Chlorella.

    PubMed

    Summerer, Monika; Sonntag, Bettina; Hörtnagl, Paul; Sommaruga, Ruben

    2009-05-01

    We assessed the photoprotective role of symbiotic Chlorella in the ciliate Paramecium bursaria by comparing their sensitivity to UV radiation (UVR) with Chlorella-reduced and Chlorella-free (aposymbiotic) cell lines of the same species. Aposymbiotic P. bursaria had significantly higher mortality than the symbiotic cell lines when exposed to UVR. To elucidate the protection mechanism, we assessed the algal distribution within the ciliate using thin-sections and transmission electron microscopy and estimated the screening factor by Chlorella based on an optical model. These analyses evidenced a substantial screening factor ranging, from 59.2% to 93.2% (320nm) for regular algal distribution. This screening efficiency reached up to approximately 100% when Chlorella algae were dislocated to the posterior region of the ciliate. The dislocation was observed in symbiotic ciliates only under exposure to UV plus photosynthetically active radiation (PAR) or to high PAR levels. Moreover, under exposure to UVB radiation and high PAR, symbiotic P. bursaria aggregated into dense spots. This behavior could represent an efficient avoidance strategy not yet described for ciliates. Analyses of the intact symbiosis and their algal symbionts for UV-screening compounds (mycosporine-like amino acids and sporopollenin) proved negative. Overall, our results show that photoprotection in this ciliate symbiosis represents an additional advantage to the hitherto postulated nutritional benefits. PMID:19195930

  20. Evaluation of higher plant virus resistance genes in the green alga, Chlorella variabilis NC64A, during the early phase of infection with Paramecium bursaria chlorella virus-1.

    PubMed

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

    2013-08-01

    With growing industrial interest in algae plus their critical roles in aquatic systems, the need to understand the effects of algal pathogens is increasing. We examined a model algal host-virus system, Chlorella variabilis NC64A and virus, PBCV-1. C. variabilis encodes 375 homologs to genes involved in RNA silencing and in response to virus infection in higher plants. Illumina RNA-Seq data showed that 325 of these homologs were expressed in healthy and early PBCV-1 infected (≤60min) cells. For each of the RNA silencing genes to which homologs were found, mRNA transcripts were detected in healthy and infected cells. C. variabilis, like higher plants, may employ certain RNA silencing pathways to defend itself against virus infection. To our knowledge this is the first examination of RNA silencing genes in algae beyond core proteins, and the first analysis of their transcription during virus infection. PMID:23701839

  1. Evaluation of higher plant virus resistance genes in the green alga, Chlorella variabilis NC64A, during the early phase of infection with Paramecium bursaria chlorella virus-1

    PubMed Central

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

    2014-01-01

    With growing industrial interest in algae plus their critical roles in aquatic systems, the need to understand the effects of algal pathogens is increasing. We examined a model algal host–virus system, Chlorella variabilis NC64A and virus, PBCV-1. C. variabilis encodes 375 homologs to genes involved in RNA silencing and in response to virus infection in higher plants. Illumina RNA-Seq data showed that 325 of these homologs were expressed in healthy and early PBCV-1 infected (≤60 min) cells. For each of the RNA silencing genes to which homologs were found, mRNA transcripts were detected in healthy and infected cells. C. variabilis, like higher plants, may employ certain RNA silencing pathways to defend itself against virus infection. To our knowledge this is the first examination of RNA silencing genes in algae beyond core proteins, and the first analysis of their transcription during virus infection. PMID:23701839

  2. [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. PMID:26489344

  3. 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

  4. Evolutionary trade-off between defence against grazing and competitive ability in a simple unicellular alga, Chlorella vulgaris.

    PubMed Central

    Yoshida, Takehito; Hairston, Nelson G.; Ellner, Stephen P.

    2004-01-01

    Trade-offs between defence and other fitness components are expected in principle, and can have major qualitative impacts on ecological dynamics. Here we show that such a trade-off exists even in the simple unicellular alga Chlorella vulgaris. We grew algal populations for multiple generations in either the presence ('grazed algae') or absence ('non-grazed algae') of the grazing rotifer Brachionus calyciflorus, and then evaluated their defence and competitive abilities. Grazed algae were better defended, yielding rotifer growth rate 32% below that of animals fed non-grazed algae, but they also had diminished competitive ability, with a growth rate under nutrient-limiting conditions 28% below that of non-grazed algae. Grazed algae also had a smaller cell size and were more concentrated in carbon and nitrogen. Thus, C. vulgaris genotypes vary phenotypically in their position along a trade-off curve between defence against grazing and competitive ability. This genetic variation underlies rapid algal evolution that significantly alters the ecological predator-prey cycles between rotifers and algae. PMID:15347519

  5. 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

  6. 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

  7. 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. PMID:24950094

  8. Stereocontrolled reduction of alpha- and beta-keto esters with micro green algae, Chlorella strains.

    PubMed

    Ishihara, K; Yamaguchi, H; Adachi, N; Hamada, H; Nakajima, N

    2000-10-01

    The stereocontrolled reduction of alpha- and beta-keto esters using micro green algae was accomplished by a combination of the cultivation method and the introduction of an additive. The reduction of ethyl pyruvate and ethyl benzoylformate by the photoautotrophically cultivated Chlorella sorokiniana gave the corresponding alcohol in high e.e. (>99% e.e. (S) and >99% e.e. (R), respectively). In the presence of glucose as an additive, the reduction of ethyl 3-methyl-2-oxobutanoate by the heterotrophically cultivated C. sorokiniana afforded the corresponding (R)-alcohol. On the other hand, the reduction in the presence of ethyl propionate gave the (S)-alcohol. Ethyl 2-methyl-3-oxobutanoate was reduced in the presence of glycerol by the photoautotrophically cultivated C. sorokiniana or the heterotrophically cultivated C. sorokiniana to the corresponding syn-(2R,3S)-hydroxy ester with high diastereo- and enantiomeric excess (e.e.). Some additives altered the stereochemical course in the reduction of alpha- and beta-keto esters. PMID:11129581

  9. Temporal changes in the toxicity of pentachlorophenol to Chlorella pyrenidosa algae.

    PubMed

    Huang, Guo-Lan; Mao, Yuxiang; Headley, John V; Sun, Hong-Wen

    2003-09-01

    The toxicity of pentachlorophenol (PCP) on Chlorella pyrenidosa algae was investigated with specific attention given to possible variation of toxic effects with time. A concentration-effect relationship was observed in which there was significant inhibition of PCP on cell density and chlorophyll A content. The inhibition rate of PCP on cell density was dependent on exposure time. The IC50 values after exposure times of 2, 4 and 6 days for cell growth were 4.18 +/- 0.49, 3.49 +/- 0.40 and 3.30 +/- 0.26 mg/L, respectively. There was also inhibition of chlorophyll A production, which appeared to increase marginally with exposure time for a given concentration of PCP. The corresponding IC50 values on day 2, 4 and 6 were 2.30 +/- 0.12, 2.63 +/- 0.38 and 3.30 +/- 0.34 mg/L, respectively. The effect of PCP on nitrate reductase (NR), was first stimulation followed by an inhibition phase. It is postulated that the observed temporal changes in the activity of nitrate reductase (NR) may occur through the addition or loss of phosphorus in the NR protein. PMID:12929714

  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. 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. PMID:22078227

  12. [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

  13. Influence of plaque-forming bacterium, Rhodobacteraceae sp. on the growth of Chlorella vulgaris.

    PubMed

    Chen, Zhangran; Zhang, Jingyan; Lei, Xueqian; Zhang, Bangzhou; Cai, Guanjing; Zhang, Huajun; Li, Yi; Zheng, Wei; Tian, Yun; Xu, Hong; Zheng, Tianling

    2014-10-01

    Experiments were conducted to find out the molecular features, infection process of a special alga plaque-forming microorganism and its potential influence on the biomass of Chlorella vulgaris during the infection process. Direct contact between the algal cell and the bacterium may be the primary steps needed for the bacterium to lyse the alga. Addition of C. vulgaris cells into f/2 medium allowed us obtain the object bacterium. The 16S rRNA gene sequence comparisons results showed that the plaque-forming bacterium kept the closest relationship with Labrenzia aggregata IAM 12614(T) at 98.90%. The existence of the bacterium could influence both the dry weight and lipid content of C. vulgaris. This study demonstrated that direct cell wall disruption of C. vulgaris by the bacterium would be a potentially effective method to utilize the biomass of microalgae. PMID:25086475

  14. 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

  15. Response of the freshwater Alga chlorella vulgaris to trichloroisocyanuric acid and ciprofloxacin.

    PubMed

    Nie, Xiangping; Wang, Xiang; Chen, Jufang; Zitko, Vladimir; An, Taichen

    2008-01-01

    The effects of trichloroisocyanuric acid (TCCA) and ciprofloxacin (CPFX) on the freshwater alga Chlorella vulgaris were assessed by toxicity bioassays and by the values of biomarkers in phase I and phase II. The biomarkers included growth rate, concentration of chlorophyll a, activities of 7-ethoxyresorufin-O-dealkylases (EROD), glutathione S-transferase (GST), catalase (CAT), and total glutathione (GSH). Ciprofloxacin was a weaker growth inhibitor than TCCA but, at a concentration of greater than 12.5 mg/L, decreased the growth of C. vulgaris. Concentration of chlorophyll a showed a similar trend. The 96-h median effective concentration (EC50; i.e., 50% reduction in growth relative to the control) of CPFX was 20.6 mg/L. Trichloroisocyanuric acid was a strong growth inhibitor and, at concentrations of greater than 0.80 mg/L, caused 100% inhibition on 24-h exposure. The 96-h EC50 of TCCA was 0.313 mg/L. Ciprofloxacin and TCCA affected the phase I and phase II enzyme activities differently. On exposure to CPFX, both EROD and GSH decreased at low CPFX concentrations (<5.0 mg/L) and increased at high CPFX concentrations (>12.5 mg/L), and CAT and GST exhibited induction at low concentrations and inhibition at high concentrations. In TCCA exposure, GST activity was significantly stimulated, and GSH concentration was increased. Catalase activity increased only at TCCA concentrations of greater than 0.12 mg/L, and no change in EROD activity was observed. PMID:18092852

  16. 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.

  17. 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. PMID:25791330

  18. 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

  19. 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

  20. Amelioration of arsenic toxicity in rice: Comparative effect of inoculation of Chlorella vulgaris and Nannochloropsis sp. on growth, biochemical changes and arsenic uptake.

    PubMed

    Upadhyay, A K; Singh, N K; Singh, R; Rai, U N

    2016-02-01

    The present study was conducted to assess the responses of rice (Oryza sativa L. var. Triguna) by inoculating alga; Chlorella vulgaris and Nannochlropsis sp. supplemented with As(III) (50µM) under hydroponics condition. Results showed that reduced growth variables and protein content in rice plant caused by As toxicity were restored in the algae inoculated plants after 7d of treatment. The rice plant inoculated with Nannochloropsis sp. exhibited a better response in terms of increased root, shoot length and biomass than C. vulgaris under As(III) treatment. A significant reduction in cellular toxicity (thiobarbituric acid reactive substances) and antioxidant enzyme (SOD, APX and GR) activities were observed in algae inoculated rice plant under As(III) treatment in comparison to uninoculated rice. In addition, rice treated with As(III), accumulated 35.05mgkg(-1)dw arsenic in the root and 29.96mgkg(-1)dw in the shoot. However, lower accumulation was observed in As(III) treated rice inoculated with C. vulgaris (24.09mg kg(-1)dw) and Nannochloropsis sp. (20.66mgkg(-1)dw) in the roots, while in shoot, it was 20.10mgkg(-1)dw and 11.67mgkg(-1)dw, respectively. Results demonstrated that application of these algal inoculum ameliorates toxicity and improved tolerance in rice through reduced As uptake and modulating antioxidant enzymes. Thus, application of algae could provide a low-cost and eco-friendly mitigation approach to reduce accumulation of arsenic in edible part of rice as well as higher yield in the As contaminated agricultural field. PMID:26473328

  1. 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. PMID:26234438

  2. Effects of DDT and BHC on amino acid content and its varieties in Chlorella vulgaris Beij. and Cladophora sp.

    NASA Astrophysics Data System (ADS)

    Lin, Yixiong

    1991-03-01

    In Chlorella vulgaris Beij. and Cladophora sp. treated with different concentrations of r-BHC and p, p-DDT, the protein and free amino acid content in both were higher than those in the controls, and the free amino acid content was even higher than the protein amino acid content.

  3. Biomass Production Potential of a Wastewater Alga Chlorella vulgaris ARC 1 under Elevated Levels of CO2 and Temperature

    PubMed Central

    Chinnasamy, Senthil; Ramakrishnan, Balasubramanian; Bhatnagar, Ashish; Das, Keshav C.

    2009-01-01

    The growth response of Chlorella vulgaris was studied under varying concentrations of carbon dioxide (ranging from 0.036 to 20%) and temperature (30, 40 and 50°C). The highest chlorophyll concentration (11 μg mL–1) and biomass (210 μg mL–1), which were 60 and 20 times more than that of C. vulgaris at ambient CO2 (0.036%), were recorded at 6% CO2 level. At 16% CO2 level, the concentrations of chlorophyll and biomass values were comparable to those at ambient CO2 but further increases in the CO2 level decreased both of them. Results showed that the optimum temperature for biomass production was 30°C under elevated CO2 (6%). Although increases in temperature above 30°C resulted in concomitant decrease in growth response, their adverse effects were significantly subdued at elevated CO2. There were also differential responses of the alga, assessed in terms of NaH14CO3 uptake and carbonic anhydrase activity, to increases in temperature at elevated CO2. The results indicated that Chlorella vulgaris grew better at elevated CO2 level at 30°C, albeit with lesser efficiencies at higher temperatures. PMID:19333419

  4. Repeated use of stable magnetic flocculant for efficient harvest of oleaginous Chlorella sp.

    PubMed

    Lee, Kyubock; Lee, So Yeun; Praveenkumar, Ramasamy; Kim, Bohwa; Seo, Jung Yoon; Jeon, Sang Goo; Na, Jeong-Geol; Park, Ji-Yeon; Kim, Dong-Myung; Oh, You-Kwan

    2014-09-01

    In the present study, a simple magnetic-particle recycling strategy was developed for harvest of the oleaginous microalga Chlorella sp. KR-1. The method entails the flocculation of microalgal cells and bare-Fe3O4 magnetic particles (bMP) by electrostatic attraction and the subsequent recovery of the bMP from the harvested flocs by electrostatic repulsion below and above the isoelectric points (IEP), respectively. For 10 recycles, the bMP showed 94-99% and 90-97% harvest and recovery efficiencies, respectively. Furthermore, neither the use of bMP nor pH adjustment showed any adverse effect on the microalgal cell growth or the co-existing bacterial species, as confirmed from the subsequent medium-recycling test and denaturing gradient gel electrophoresis (DGGE) analysis. PMID:24995878

  5. 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. PMID:22033900

  6. Nitrogen starvation induced oxidative stress in an oil-producing green alga Chlorella sorokiniana C3.

    PubMed

    Zhang, Yun-Ming; Chen, Hui; 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

  7. 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

  8. 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

  9. 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

  10. The influence of salinity on the toxicity of selected sulfonamides and trimethoprim towards the green algae Chlorella vulgaris.

    PubMed

    Borecka, Marta; Białk-Bielińska, Anna; Haliński, Łukasz P; Pazdro, Ksenia; Stepnowski, Piotr; Stolte, Stefan

    2016-05-01

    This paper presents the investigation of the influence of salinity variations on the toxicity of sulfapyridine, sulfamethoxazole, sulfadimethoxine and trimethoprim towards the green algae Chlorella vulgaris after exposure times of 48 and 72 h. In freshwater the EC50 values ranged from 0.98 to 123.22 mg L(-1) depending on the compound. The obtained results revealed that sulfamethoxazole and sulfapyridine were the most toxic, while trimethoprim was the least toxic pharmaceutical to the selected organism. Deviations between the nominal and real test concentrations were determined via instrumental analysis to support the interpretation of ecotoxicological data. The toxicity effects were also tested in saline water (3, 6 and 9 PSU). The tendency that the toxicity of selected pharmaceuticals decreases with increasing salinity was observed. Higher salinity implies an elevated concentration of inorganic monovalent cations that are capable of binding with countercharges available on algal surfaces (hydroxyl functional groups). Hence it can reduce the permeability of pharmaceuticals through the algal cell walls, which could be the probable reason for the observed effect. Moreover, for the classification of the mode of toxic action, the toxic ratio concept was applied, which indicated that the effects of the investigated drugs towards algae are caused by the specific mode of toxic action. PMID:26835894

  11. Enhanced acetyl-CoA production is associated with increased triglyceride accumulation in the green alga Chlorella desiccata

    PubMed Central

    Avidan, Omri; Brandis, Alexander; Rogachev, Ilana; Pick, Uri

    2015-01-01

    Triglycerides (TAGs) from microalgae can be utilized as food supplements and for biodiesel production, but little is known about the regulation of their biosynthesis. This work aimed to test the relationship between acetyl-CoA (Ac-CoA) levels and TAG biosynthesis in green algae under nitrogen deprivation. A novel, highly sensitive liquid chromatography mass spectrometry (LC-MS/MS) technique enabled us to determine the levels of Ac-CoA, malonyl-CoA, and unacetylated (free) CoA in green microalgae. A comparative study of three algal species that differ in TAG accumulation levels shows that during N starvation, Ac-CoA levels rapidly rise, preceding TAG accumulation in all tested species. The levels of Ac-CoA in the high TAG accumulator Chlorella desiccata exceed the levels in the moderate TAG accumulators Dunaliella tertiolecta and Chlamydomonas reinhardtii. Similarly, malonyl-CoA and free CoA levels also increase, but to lower extents. Calculated cellular concentrations of Ac-CoA are far lower than reported K mAc-CoA values of plastidic Ac-CoA carboxylase (ptACCase) in plants. Transcript level analysis of plastidic pyruvate dehydrogenase (ptPDH), the major chloroplastic Ac-CoA producer, revealed rapid induction in parallel with Ac-CoA accumulation in C. desiccata, but not in D. tertiolecta or C. reinhardtii. It is proposed that the capacity to accumulate high TAG levels in green algae critically depends on their ability to divert carbon flow towards Ac-CoA. This requires elevation of the chloroplastic CoA pool level and enhancement of Ac-CoA biosynthesis. These conclusions may have important implications for future genetic manipulation to enhance TAG biosynthesis in green algae. PMID:25922486

  12. Enhanced acetyl-CoA production is associated with increased triglyceride accumulation in the green alga Chlorella desiccata.

    PubMed

    Avidan, Omri; Brandis, Alexander; Rogachev, Ilana; Pick, Uri

    2015-07-01

    Triglycerides (TAGs) from microalgae can be utilized as food supplements and for biodiesel production, but little is known about the regulation of their biosynthesis. This work aimed to test the relationship between acetyl-CoA (Ac-CoA) levels and TAG biosynthesis in green algae under nitrogen deprivation. A novel, highly sensitive liquid chromatography mass spectrometry (LC-MS/MS) technique enabled us to determine the levels of Ac-CoA, malonyl-CoA, and unacetylated (free) CoA in green microalgae. A comparative study of three algal species that differ in TAG accumulation levels shows that during N starvation, Ac-CoA levels rapidly rise, preceding TAG accumulation in all tested species. The levels of Ac-CoA in the high TAG accumulator Chlorella desiccata exceed the levels in the moderate TAG accumulators Dunaliella tertiolecta and Chlamydomonas reinhardtii. Similarly, malonyl-CoA and free CoA levels also increase, but to lower extents. Calculated cellular concentrations of Ac-CoA are far lower than reported K mAc-CoA values of plastidic Ac-CoA carboxylase (ptACCase) in plants. Transcript level analysis of plastidic pyruvate dehydrogenase (ptPDH), the major chloroplastic Ac-CoA producer, revealed rapid induction in parallel with Ac-CoA accumulation in C. desiccata, but not in D. tertiolecta or C. reinhardtii. It is proposed that the capacity to accumulate high TAG levels in green algae critically depends on their ability to divert carbon flow towards Ac-CoA. This requires elevation of the chloroplastic CoA pool level and enhancement of Ac-CoA biosynthesis. These conclusions may have important implications for future genetic manipulation to enhance TAG biosynthesis in green algae. PMID:25922486

  13. Mechanistic characterization of omega-3 desaturation in the green alga Chlorella vulgaris.

    PubMed

    Daligault, Franck; Reed, Darwin W; Savile, Christopher K; Nugier-Chauvin, Caroline; Patin, Henri; Covello, Patrick S; Buist, Peter H

    2003-08-01

    alpha-Linolenic acid (ALA, 9(Z),12(Z),15(Z)-octadecatrienoic acid) derivatives are important plant lipids which play a critical key role in cold tolerance. The final steps of ALA biosynthesis feature a series of regio- and stereoselective dehydrogenation reactions which are catalyzed by a set of enzymes known as fatty acid desaturases. In conjunction with ongoing research into the structural biology of these remarkable catalysts, we have examined the mechanism of double bond introduction at C15,16 as it occurs in a model photosynthetic organism, Chlorella vulgaris. The individual deuterium kinetic isotope effects associated with the C-H bond cleavages at C-15 and C-16 of a thialinoleoyl analogue were measured via competition experiments using appropriately deuterium-labelled 7-thia substrates. A large kinetic isotope effect (KIE) (k(H)/k(D)=10.2+/-2.8) was observed for the C-H bond-breaking step at C-15 while the C-H bond cleavage at C-16 was found to be relatively insensitive to deuterium substitution (k(H)/k(D)=0.8+/-0.2). These results point to C-15 as the site of initial oxidation in omega-3 desaturation and imply that the Chlorella and corresponding plant systems share a common active site architecture. PMID:12877913

  14. 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

  15. Extraction fatty acid as a source to produce biofuel in microalgae Chlorella sp. and Spirulina sp. using supercritical carbon dioxide

    NASA Astrophysics Data System (ADS)

    Tai, Do Chiem; Hai, Dam Thi Thanh; Vinh, Nguyen Hanh; Phung, Le Thi Kim

    2016-06-01

    In this research, the fatty acids of isolated microalgae were extracted by some technologies such as maceration, Soxhlet, ultrasonic-assisted extraction and supercritical fluid extraction; and analyzed for biodiesel production using GC-MS. This work deals with the extraction of microalgae oil from dry biomass by using supercritical fluid extraction method. A complete study at laboratory of the influence of some parameters on the extraction kinetics and yields and on the composition of the oil in terms of lipid classes and profiles is proposed. Two types of microalgae were studied: Chlorella sp. and Spirulina sp. For the extraction of oil from microalgae, supercritical CO2 (SC-CO2) is regarded with interest, being safer than n-hexane and offering a negligible environmental impact, a short extraction time and a high-quality final product. Whilst some experimental papers are available on the supercritical fluid extraction (SFE) of oil from microalgae, only limited information exists on the kinetics of the process. These results demonstrate that supercritical CO2 extraction is an efficient method for the complete recovery of the neutral lipid phase.

  16. 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. PMID:25899143

  17. CHLORELLA VIRUSES

    PubMed Central

    Yamada, Takashi; Onimatsu, Hideki; Van Etten, James L.

    2007-01-01

    Chlorella viruses or chloroviruses are large, icosahedral, plaque‐forming, double‐stranded‐DNA—containing viruses that replicate in certain strains of the unicellular green alga Chlorella. DNA sequence analysis of the 330‐kbp genome of Paramecium bursaria chlorella virus 1 (PBCV‐1), the prototype of this virus family (Phycodnaviridae), predict ∼366 protein‐encoding genes and 11 tRNA genes. The predicted gene products of ∼50% of these genes resemble proteins of known function, including many that are completely unexpected for a virus. In addition, the chlorella viruses have several features and encode many gene products that distinguish them from most viruses. These products include: (1) multiple DNA methyltransferases and DNA site‐specific endonucleases, (2) the enzymes required to glycosylate their proteins and synthesize polysaccharides such as hyaluronan and chitin, (3) a virus‐encoded K+ channel (called Kcv) located in the internal membrane of the virions, (4) a SET domain containing protein (referred to as vSET) that dimethylates Lys27 in histone 3, and (5) PBCV‐1 has three types of introns; a self‐splicing intron, a spliceosomal processed intron, and a small tRNA intron. Accumulating evidence indicates that the chlorella viruses have a very long evolutionary history. This review mainly deals with research on the virion structure, genome rearrangements, gene expression, cell wall degradation, polysaccharide synthesis, and evolution of PBCV‐1 as well as other related viruses. PMID:16877063

  18. 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.

  19. The interactive effects of microcystin-LR and cylindrospermopsin on the growth rate of the freshwater algae Chlorella vulgaris.

    PubMed

    Pinheiro, Carlos; Azevedo, Joana; Campos, Alexandre; Vasconcelos, Vítor; Loureiro, Susana

    2016-05-01

    Microcystin-LR (MC-LR) and cylindrospermopsin (CYN) are the most representative cyanobacterial cyanotoxins. They have been simultaneously detected in aquatic systems, but their combined ecotoxicological effects to aquatic organisms, especially microalgae, is unknown. In this study, we examined the effects of these cyanotoxins individually and as a binary mixture on the growth rate of the freshwater algae Chlorella vulgaris. Using the MIXTOX tool, the reference model concentration addition (CA) was selected to evaluate the combined effects of MC-LR and CYN on the growth of the freshwater green algae due to its conservative prediction of mixture effect for putative similar or dissimilar acting chemicals. Deviations from the CA model such as synergism/antagonism, dose-ratio and dose-level dependency were also assessed. In single exposures, our results demonstrated that MC-LR and CYN had different impacts on the growth rates of C. vulgaris at the highest tested concentrations, being CYN the most toxic. In the mixture exposure trial, MC-LR and CYN showed a synergistic deviation from the conceptual model CA as the best descriptive model. MC-LR individually was not toxic even at high concentrations (37 mg L(-1)); however, the presence of MC-LR at much lower concentrations (0.4-16.7 mg L(-1)) increased the CYN toxicity. From these results, the combined exposure of MC-LR and CYN should be considered for risk assessment of mixtures as the toxicity may be underestimated when looking only at the single cyanotoxins and not their combination. This study also represents an important step to understand the interactions among MC-LR and CYN detected previously in aquatic systems. PMID:26910533

  20. Azoxystrobin-induced excessive reactive oxygen species (ROS) production and inhibition of photosynthesis in the unicellular green algae Chlorella vulgaris.

    PubMed

    Liu, Lei; Zhu, Bin; Wang, Gao-Xue

    2015-05-01

    This study investigated the short-term toxicity of azoxystrobin (AZ), one of strobilurins used as an effective fungicidal agent to control the Asian soybean rust, on aquatic unicellular algae Chlorella vulgaris. The median percentile inhibition concentration (IC₅₀) of AZ for C. vulgaris was found to be 510 μg L(-1). We showed that the algal cells were obviously depressed or shrunk in 300 and 600 μg L(-1) AZ treatments by using the electron microscopy. Furthermore, 19, 75, and 300 μg L(-1) AZ treatments decreased the soluble protein content and chlorophyll concentrations in C. vulgaris and altered the energy-photosynthesis-related mRNA expression levels in 48- and 96-h exposure periods. Simultaneously, our results showed that AZ could increase the total antioxidant capacity (T-AOC) level and compromise superoxide dismutase (SOD), peroxidase (POD), glutathione S transferase (GST), glutathione peroxidase (GPx) activities, and glutathione (GSH) content. These situations might render C. vulgaris more vulnerable to oxidative damage. Overall, the present study indicated that AZ might be toxic to the growth of C. vulgaris, affect energy-photosynthesis-related mRNA expressions, and induce reactive oxygen species (ROS) overproduction in C. vulgaris. PMID:25672875

  1. 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

  2. Strain improvement of Chlorella sp. for phenol biodegradation by adaptive laboratory evolution.

    PubMed

    Wang, Libo; Xue, Chuizhao; Wang, Liang; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

    2016-04-01

    Microalgae are highly efficient photosynthesis cell factories for CO2 capture, biofuel productions and wastewater treatment. Phenol is a typical environmental contaminant. Microalgae normally have a low tolerance for, and a low degradation rate to, high concentration of phenol. Adaptive laboratory evolution was performed for phenolic wastewater treatment by Chlorella sp. The resulting strain was obtained after 31 cycles (about 95d) under 500mg/L phenol as environmental stress. It could grow under 500mg/L and 700mg/L phenol without significant inhibition. The maximal biomass concentrations of the resulting strain at day 8 were 3.40g/L under 500mg/L phenol and 2.70g/L under 700mg/L phenol, respectively. They were more than two times of those of the original strain. In addition, 500mg/L phenol was fully removed by the resulting strain in 7d when the initial cell density was 0.6g/L. PMID:26803904

  3. 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.

  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. 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. PMID:24696841

  6. Mechanism of fatty acid desaturation in the green alga Chlorella vulgaris.

    PubMed

    Behrouzian, B; Fauconnot, L; Daligault, F; Nugier-Chauvin, C; Patin, H; Buist, P H

    2001-06-01

    The hypothesis that the Delta9 desaturase of Chlorella vulgaris might operate by a synchronous mechanism has been tested using a kinetic isotope effect (KIE) approach. Thus the intermolecular primary deuterium KIE on the individual C-H bond cleavage steps involved in Delta9 desaturation have been determined by incubating growing cultures of C. vulgaris (strain 211/8K) with mixtures of the appropriate regiospecifically deuterated fatty acid analogues. Our analysis shows that the introduction of a double bond between C-9 and C-10 occurs in two discrete steps as the cleavage of the C9-H bond is very sensitive to isotopic substitution (kH/kD = 6.6 +/- 0.3) whereas a negligible isotope effect (kH/kD = 1.05 +/- 0.05) was observed for the C10-H bond-breaking step. Similar results were obtained for linoleic acid biosynthesis (Delta12 desaturation). These data clearly rule out a synchronous mechanism for these reactions. PMID:11422385

  7. Valorization of Rhizoclonium sp. algae via pyrolysis and catalytic pyrolysis.

    PubMed

    Casoni, Andrés I; Zunino, Josefina; Piccolo, María C; Volpe, María A

    2016-09-01

    The valorization of Rhizoclonium sp. algae through pyrolysis for obtaining bio-oils is studied in this work. The reaction is carried out at 400°C, at high contact time. The bio-oil has a practical yield of 35% and is rich in phytol. Besides, it is simpler than the corresponding to lignocellulosic biomass due to the absence of phenolic compounds. This property leads to a bio-oil relatively stable to storage. In addition, heterogeneous catalysts (Al-Fe/MCM-41, SBA-15 and Cu/SBA-15), in contact with algae during pyrolysis, are analyzed. The general trend is that the catalysts decrease the concentration of fatty alcohols and other high molecular weight products, since their mild acidity sites promote degradation reactions. Thus, the amount of light products increases upon the use of the catalysts. Particularly, acetol concentration in the bio-oils obtained from the catalytic pyrolysis with SBA-15 and Cu/SBA-15 is notably high. PMID:27253478

  8. Evaluation of zinc oxide nanoparticles toxicity on marine algae chlorella vulgaris through flow cytometric, cytotoxicity and oxidative stress analysis.

    PubMed

    Suman, T Y; Radhika Rajasree, S R; Kirubagaran, R

    2015-03-01

    The increasing industrial use of nanomaterials during the last decades poses a potential threat to the environment and in particular to organisms living in the aquatic environment. In the present study, the toxicity of zinc oxide nanoparticles (ZnO NPs) was investigated in Marine algae Chlorella vulgaris (C. vulgaris). High zinc dissociation from ZnONPs, releasing ionic zinc in seawater, is a potential route for zinc assimilation and ZnONPs toxicity. To examine the mechanism of toxicity, C. vulgaris were treated with 50mg/L, 100mg/L, 200mg/L and 300 mg/L ZnO NPs for 24h and 72h. The detailed cytotoxicity assay showed a substantial reduction in the viability dependent on dose and exposure. Further, flow cytometry revealed the significant reduction in C. vulgaris viable cells to higher ZnO NPs. Significant reductions in LDH level were noted for ZnO NPs at 300 mg/L concentration. The activity of antioxidant enzyme superoxide dismutase (SOD) significantly increased in the C. vulgaris exposed to 200mg/L and 300 mg/L ZnO NPs. The content of non-enzymatic antioxidant glutathione (GSH) significantly decreased in the groups with a ZnO NPs concentration of higher than 100mg/L. The level of lipid peroxidation (LPO) was found to increase as the ZnO NPs dose increased. The FT-IR analyses suggested surface chemical interaction between nanoparticles and algal cells. The substantial morphological changes and cell wall damage were confirmed through microscopic analyses (FESEM and CM). PMID:25483368

  9. Enzymatic conversion of glutamate to delta-aminolevulinate in soluble extracts of the unicellular green alga, Chlorella vulgaris.

    PubMed

    Weinstein, J D; Beale, S I

    1985-03-01

    Cell-free preparations from the unicellular green alga, Chlorella vulgaris, catalyze the conversion of glutamate to delta-aminolevulinate, which is the first committed step in heme and chlorophyll biosynthesis. Most activity remains in the supernatant fraction after centrifugation at 264,000g. Additional activity can be solubilized from the high-speed pellet by treatment with 0.5 M NaCl. After gel filtration through Sephadex G-25, the reaction catalyzed by the high-speed supernatant requires glutamate, ATP, Mg2+, and NADPH. Boiled extract is inactive. The pH optimum is between 7.8 and 7.9 and the temperature optimum is 30 degrees C. Concentrations required for half-maximal activity are 0.05 mM glutamate, 0.4 mM ATP, 6 mM MgCl2, and 0.4 mM NADPH or 0.7 mM NADH. The reaction requires no additional amino donor. Involvement of pyridoxal phosphate in the catalytic mechanism is suggested by sensitivity to pyridoxal antagonists; 50% inhibition is achieved with 5 microM gabaculine or 0.4 mM aminooxyacetate. Involvement of two or more enzymes is suggested by the nonlinear reaction rate dependence on protein concentration. Evidence for the involvement of an activated glutamate intermediate was obtained by product formation after sequential addition and removal of substrates, and by inhibition (80%) with 1 mM hydroxylamine. Protoheme inhibits the activity by 50% at 1.2 microM. Preincubation of the extract with ATP causes stimulation and/or stabilization of the activity compared to preincubation without ATP or no preincubation. In preparations obtained from C. vulgaris strain C-10, which requires light for greening, dark-grown cells yield one-third as much activity as 4-h-greened cells. PMID:3977321

  10. Benefits of oral and topical administration of ROQUETTE Chlorella sp. on skin inflammation and wound healing in mice.

    PubMed

    Hidalgo-Lucas, Sophie; Bisson, Jean-Francois; Duffaud, Anais; Nejdi, Amine; Guerin-Deremaux, Laetitia; Baert, Blandine; Saniez-Degrave, Marie-Helene; Rozan, Pascale

    2014-01-01

    The human body is constantly exposed to the risk of traumatic lesions. Chlorella is a green microalgae enriched with nutrients, vitamins, minerals and chlorophyll. In some communities, Chlorella is a traditional medicinal plant used for the management of inflammation-related diseases. ROQUETTE Chlorella sp. (RCs) was investigated by oral administration (125, 250 and 500 mg/kg) and cutaneous application (2.5, 5.0 and 10.0%) to evaluate its impact in two dermatological disorder models in mice: skin inflammation and wound healing. For skin inflammation, it was administered during 14 days starting one week before the induction of chronic skin inflammation by repeated cutaneous application of 12-Otetradecanoylphorbol 13-acetate (TPA). For wound healing the microalgae was administered by topical application after scarification of the skin until complete wound healing. Results indicated that oral and topical administrations of the two higher doses of RCs had significant effects on macroscopic score of skin inflammation with an efficient effect on microscopic score with cutaneous application. The microalgae had also efficient effect on healing process and duration of wound healing for both administration routes and particularly at the two highest doses of RCs. These findings suggest that administration of RCs by both oral and topical routes appeared to have beneficial effects on skin lesions. PMID:24965517

  11. 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

  12. The influence of dissolved and surface-bound humic acid on the toxicity of TiO₂ nanoparticles to Chlorella sp.

    PubMed

    Lin, Daohui; Ji, Jing; Long, Zhifeng; Yang, Kun; Wu, Fengchang

    2012-09-15

    NOM is likely to coat TiO₂ nanoparticles (nano-TiO₂) discharged into the aquatic environment and influence the nanotoxicity to aquatic organisms, which however has not been well investigated. This study explored the influence of nanoparticle surface-bound humic acid (HA, as a model NOM) as well as dissolved HA on the toxicity of nano-TiO₂ to Chlorella sp., with a specific focus on adhesion of the nanoparticles to the algae. Results showed that nano-TiO₂ and the dissolved HA could inhibit the algal growth with an IC₅₀ of 4.9 and 8.4 mg L⁻¹, respectively, while both dissolved and nanoparticle surface-bound HA could significantly alleviate the algal toxicity of nano-TiO₂. IC₅₀ of nano-TiO₂ increased to 18 mg L⁻¹ in the presence of 5 mg L⁻¹ of the dissolved HA and to 48 mg L⁻¹ as the result of surface-saturation by HA. Co-precipitation experiment and transmission electron microscopy observation revealed that both dissolved and nanoparticle surface-bound HA prevented the adhesion of nano-TiO₂ to the algal cells due to the increased electrosteric repulsion. The generation of intracellular reactive oxygen species (ROS) was significantly limited by the dissolved and nanoparticle surface-bound HA. The prevention of adhesion and inhibition of ROS generation could account for the HA-mitigated nanotoxicity. PMID:22704133

  13. 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. PMID:23928654

  14. 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

  15. Microalgal biomass production and on-site bioremediation of carbon dioxide, nitrogen oxide and sulfur dioxide from flue gas using Chlorella sp. cultures.

    PubMed

    Chiu, Sheng-Yi; Kao, Chien-Ya; Huang, Tzu-Ting; Lin, Chia-Jung; Ong, Seow-Chin; Chen, Chun-Da; Chang, Jo-Shu; Lin, Chih-Sheng

    2011-10-01

    The growth and on-site bioremediation potential of an isolated thermal- and CO₂-tolerant mutant strain, Chlorella sp. MTF-7, were investigated. The Chlorella sp. MTF-7 cultures were directly aerated with the flue gas generated from coke oven of a steel plant. The biomass concentration, growth rate and lipid content of Chlorella sp. MTF-7 cultured in an outdoor 50-L photobioreactor for 6 days was 2.87 g L⁻¹ (with an initial culture biomass concentration of 0.75 g L⁻¹), 0.52 g L⁻¹ d⁻¹ and 25.2%, respectively. By the operation with intermittent flue gas aeration in a double-set photobioreactor system, average efficiency of CO₂ removal from the flue gas could reach to 60%, and NO and SO₂ removal efficiency was maintained at approximately 70% and 50%, respectively. Our results demonstrate that flue gas from coke oven could be directly introduced into Chlorella sp. MTF-7 cultures to potentially produce algal biomass and efficiently capture CO₂, NO and SO₂ from flue gas. PMID:21802285

  16. Effects on growth, antioxidant enzyme activity and levels of extracellular proteins in the green alga Chlorella vulgaris exposed to crude cyanobacterial extracts and pure microcystin and cylindrospermopsin.

    PubMed

    Campos, Alexandre; Araújo, Pedro; Pinheiro, Carlos; Azevedo, Joana; Osório, Hugo; Vasconcelos, Vitor

    2013-08-01

    Toxic cyanobacteria and cyanotoxins have been pointed as important players in the control of phytoplankton diversity and species abundance, causing ecological unbalances and contamination of the environment. In vitro experiments have been undertaken to address the impact of toxic cyanobacteria in green algae. In this regard the aim of this work was to compare the toxicity of two cyanobacteria species, Aphanizomenon ovalisporum and Microcystis aeruginosa, to the green alga Chlorella vulgaris by assessing culture growth when exposed for three and seven days to (I) cyanobacterial cell extracts and (II) pure toxins microcystin-LR (MC-LR) and cylindrospermopsin (CYN). The biochemical response of the green alga to pure toxins was also characterized, through the activity of the antioxidant markers glutathione S-transferase (GST) and glutathione peroxidase (GPx) and the expressed extracellular proteins in seven-day exposed cultures. A. ovalisporum crude extracts were toxic to C. vulgaris. Pure toxins up to 179.0 µg/L, on the other hand, stimulated the green alga growth. Growth results suggest that the toxicity of A. ovalisporum extracts is likely due to a synergistic action of CYN and other metabolites produced by the cyanobacterium. Regarding the green alga antioxidant defense mechanism, CYN at 18.4 and 179.0 µg/L increased the activity of GPx and GST while MC-LR inhibited the enzymes' activity at a concentration of 179.0 µg/L demonstrating a contrasting mode of action. Moreover the identification of F-ATPase subunit, adenylate cyclase, sulfate ABC transporter, putative porin, aspartate aminotransferase, methylene-tetrahydrofolate dehydrogenase and chlorophyll a binding proteins in the culture medium of C. vulgaris indicates that biochemical processes involved in the transport of metabolites, photosynthesis and amino acid metabolism are affected by cyanobacterial toxins and may contribute to the regulation of green alga growth. PMID:23726538

  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. 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

  19. 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

  20. Wavelength dependence of the fluorescence emission under conditions of open and closed Photosystem II reaction centres in the green alga Chlorella sorokiniana.

    PubMed

    Rizzo, Federico; Zucchelli, Giuseppe; Jennings, Robert; Santabarbara, Stefano

    2014-06-01

    The fluorescence emission characteristics of the photosynthetic apparatus under conditions of open (F0) and closed (FM) Photosystem II reaction centres have been investigated under steady state conditions and by monitoring the decay lifetimes of the excited state, in vivo, in the green alga Chlorella sorokiniana. The results indicate a marked wavelength dependence of the ratio of the variable fluorescence, FV=FM-F0, over FM, a parameter that is often employed to estimate the maximal quantum efficiency of Photosystem II. The maximal value of the FV/FM ratio is observed between 660 and 680nm and the minimal in the 690-730nm region. It is possible to attribute the spectral variation of FV/FM principally to the contribution of Photosystem I fluorescence emission at room temperature. Moreover, the analysis of the excited state lifetime at F0 and FM indicates only a small wavelength dependence of Photosystem II trapping efficiency in vivo. PMID:24561096

  1. Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator) Growth in Chlorella kessleri (Prey) Mass Cultures for Algae Biodiesel Production.

    PubMed

    Pradeep, Vishnupriya; Van Ginkel, Steven W; Park, Sichoon; Igou, Thomas; Yi, Christine; Fu, Hao; Johnston, Rachel; Snell, Terry; Chen, Yongsheng

    2015-01-01

    A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively inhibit rotifers in algae ponds, thereby protecting the algae crop. Differential toxicity tests were conducted to compare the copper sensitivity of a model rotifer-B. calyciflorus and an alga, C. kessleri. The rotifer LC50 was <0.1 ppm while the alga was not affected up to 5 ppm Cu(II). The low pH of the rotifer stomach may make it more sensitive to copper. However, when these cultures were combined, a copper concentration of 1.5 ppm was needed to inhibit the rotifer as the alga bound the copper, decreasing its bioavailability. Copper (X ppm) had no effect on downstream fatty acid methyl ester extraction. PMID:26404247

  2. Microbiota Influences Morphology and Reproduction of the Brown Alga Ectocarpus sp.

    PubMed

    Tapia, Javier E; González, Bernardo; Goulitquer, Sophie; Potin, Philippe; Correa, Juan A

    2016-01-01

    Associated microbiota play crucial roles in health and disease of higher organisms. For macroalgae, some associated bacteria exert beneficial effects on nutrition, morphogenesis and growth. However, current knowledge on macroalgae-microbiota interactions is mostly based on studies on green and red seaweeds. In this study, we report that when cultured under axenic conditions, the filamentous brown algal model Ectocarpus sp. loses its branched morphology and grows with a small ball-like appearance. Nine strains of periphytic bacteria isolated from Ectocarpus sp. unialgal cultures were identified by 16S rRNA sequencing, and assessed for their effect on morphology, reproduction and the metabolites secreted by axenic Ectocarpus sp. Six of these isolates restored morphology and reproduction features of axenic Ectocarpus sp. Bacteria-algae co-culture supernatants, but not the supernatant of the corresponding bacterium growing alone, also recovered morphology and reproduction of the alga. Furthermore, colonization of axenic Ectocarpus sp. with a single bacterial isolate impacted significantly the metabolites released by the alga. These results show that the branched typical morphology and the individuals produced by Ectocarpus sp. are strongly dependent on the presence of bacteria, while the bacterial effect on the algal exometabolome profile reflects the impact of bacteria on the whole physiology of this alga. PMID:26941722

  3. Microbiota Influences Morphology and Reproduction of the Brown Alga Ectocarpus sp.

    PubMed Central

    Tapia, Javier E.; González, Bernardo; Goulitquer, Sophie; Potin, Philippe; Correa, Juan A.

    2016-01-01

    Associated microbiota play crucial roles in health and disease of higher organisms. For macroalgae, some associated bacteria exert beneficial effects on nutrition, morphogenesis and growth. However, current knowledge on macroalgae–microbiota interactions is mostly based on studies on green and red seaweeds. In this study, we report that when cultured under axenic conditions, the filamentous brown algal model Ectocarpus sp. loses its branched morphology and grows with a small ball-like appearance. Nine strains of periphytic bacteria isolated from Ectocarpus sp. unialgal cultures were identified by 16S rRNA sequencing, and assessed for their effect on morphology, reproduction and the metabolites secreted by axenic Ectocarpus sp. Six of these isolates restored morphology and reproduction features of axenic Ectocarpus sp. Bacteria-algae co-culture supernatants, but not the supernatant of the corresponding bacterium growing alone, also recovered morphology and reproduction of the alga. Furthermore, colonization of axenic Ectocarpus sp. with a single bacterial isolate impacted significantly the metabolites released by the alga. These results show that the branched typical morphology and the individuals produced by Ectocarpus sp. are strongly dependent on the presence of bacteria, while the bacterial effect on the algal exometabolome profile reflects the impact of bacteria on the whole physiology of this alga. PMID:26941722

  4. Carbon-to-nitrogen ratio affects the biomass composition and the fatty acid profile of heterotrophically grown Chlorella sp. TISTR 8990 for biodiesel production.

    PubMed

    Singhasuwan, Somruethai; Choorit, Wanna; Sirisansaneeyakul, Sarote; Kokkaew, Nakhon; Chisti, Yusuf

    2015-12-20

    Chlorella sp. TISTR 8990 was cultivated heterotrophically in media with various initial carbon-to-nitrogen ratios (C/N ratio) and at different agitation speeds. The production of the biomass, its total fatty acid content and the composition of the fatty acids were affected by the C/N ratio, but not by agitation speed in the range examined. The biomass production was maximized at a C/N mass ratio of 29:1. At this C/N ratio, the biomass productivity was 0.68gL(-1)d(-1), or nearly 1.6-fold the best attainable productivity in photoautotrophic growth. The biomass yield coefficient on glucose was 0.62gg(-1) during exponential growth. The total fatty acids (TFAs) in the freeze-dried biomass were maximum (459mgg(-1)) at a C/N ratio of 95:1. Lower values of the C/N ratio reduced the fatty acid content of the biomass. The maximum productivity of TFAs (186mgL(-1)d(-1)) occurred at C/N ratios of 63:1 and higher. At these conditions, the fatty acids were mostly of the polyunsaturated type. Allowing the alga to remain in the stationary phase for a prolonged period after N-depletion, reduced the level of monounsaturated fatty acids and the level of polyunsaturated fatty acids increased. Biotin supplementation of the culture medium reduced the biomass productivity relative to biotin-free control, but had no effect on the total fatty acid content of the biomass. PMID:26467713

  5. Genetic engineering of the green alga Chlorella zofingiensis: a modified norflurazon-resistant phytoene desaturase gene as a dominant selectable marker.

    PubMed

    Liu, Jin; Sun, Zheng; Gerken, Henri; Huang, Junchao; Jiang, Yue; Chen, Feng

    2014-06-01

    The unicellular green alga Chlorella zofingiensis has been proposed as a promising producer of natural astaxanthin, a commercially important ketocarotenoid. But the genetic toolbox for this alga is not available. In the present study, an efficient transformation system was established for C. zofingiensis. The transformation system utilized a modified norflurazon-resistant phytoene desaturase (PDS-L516F, with an leucine-phenylalanine change at position 516) as the selectable marker. Three promoters from endogenous PDS, nitrate reductase (NIT), and ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (RBCS) genes were tested, with the RBCS promoter demonstrating the highest transformation efficiency. Inclusion of the first intron of the PDS gene further enhanced the efficiency by 91 %. Both particle bombardment and electroporation methods were examined, and the latter gave a fourfold higher transformation efficiency. The introduction of PDS-L516F, which exhibited a 33 % higher desaturation activity than the unaltered enzyme, enabled C. zofingiensis to produce 32.1 % more total carotenoids (TCs) and 54.1 % more astaxanthin. The enhanced accumulation of astaxanthin in transformants was revealed to be related to the increase in the transcripts of PDS, β-carotenoid ketolase (BKT), and hydroxylase (CHYb) genes. Our study clearly shows that the modified PDS gene is a dominant selectable marker for the transformation of C. zofingiensis and possibly for the genetic engineering of the carotenoid biosynthetic pathway. In addition, the engineered C. zofingiensis might serve as an improved source of natural astaxanthin. PMID:24584513

  6. A newly isolated Chlorella sp. from desert sand crusts exhibits a unique resistance to excess light intensity.

    PubMed

    Treves, Haim; Raanan, Hagai; Finkel, Omri M; Berkowicz, Simon M; Keren, Nir; Shotland, Yoram; Kaplan, Aaron

    2013-12-01

    We recently isolated a small green alga from a biological sand crust (BSC) in the NW Negev, Israel. Based on its 18S rRNA and rbcL genes, it is a close relative of Chlorella sorokiniana and of certain strains of C. vulgaris and C. variabilis, but differs substantially in many aspects from C. sorokiniana. Because the classification of Chlorellales is still not resolved, we designated this species as C. ohadii (Trebouxiophyceae) in honor of Professor Itzhak Ohad. Under controlled laboratory conditions, C. ohadii showed marked structural and photosynthetic performance changes, depending on the carbon source used during growth, as well as remarkable resistance to photoinhibition. CO2 -dependent O2 evolution was not affected even when exposed to a light intensity of 3500 μmole photons m(-2)  s(-1) , over 1.5 times the maximal intensity reached at the BSC surface, whereas the variable fluorescence declined sharply. We briefly discuss the use of fluorescence to assess photosynthetic rate and the implications of this finding for the assessment of global BSCs activity. PMID:23773145

  7. 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

  8. Rational design of a culture medium for the intensification of lipid storage in Chlorella sp. Performance evaluation in air-lift bioreactor.

    PubMed

    Giordano, Pablo C; Beccaria, Alejandro J; Goicoechea, Héctor C

    2014-04-01

    An optimal medium to culture Chlorella sp., microalgae capable of storage intracellular lipids was obtained. This culture medium consists of a saline base plus carbon-energy and nitrogen sources. Significant factors exerting influence on the culture parameters were selected. Then, by applying response surface methodology coupled to desirability function, an optimal formulation, specific for the heterotrophic growth of Chlorella sp. that allows maximizing lipid concentration was obtained. During the experimental verification, the possibility of replacing commercial glucose by hydrolysates obtained from lignocellulosic materials was evaluated. Biochemical hydrolysate of corn bran allowed obtaining important improvements in lipid concentration. Finally, the optimal formulation was evaluated in an air-lift bioreactor performing a fed-batch culture. Culturing the strain in these conditions allowed rising lipid concentrations. PMID:24607464

  9. 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

  10. Toxicity of chlorinated benzenes to marine algae

    NASA Astrophysics Data System (ADS)

    Ma, Yan-Jun; Wang, Xiu-Lin; Yu, Wei-Jun; Zhang, Li-Jun; Sun, Han-Zhang

    1997-12-01

    Growth of Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp., Platymonas subcordiformis and Phaeodactylum tricornutum exposed to monochlorobenzene (MCB), 1,2-dichlorobenzene (1,2-DCB), 1, 2, 3, 4-tetrachlorobenzene (1, 2, 3, 4-TeCB) and pentachlorobenzene (PeCB) was tested. Tests of 72 h- EC 50 values showed that the toxicity ranged in the order: MCB<1,2-DCB<1,2,3,4-TeCBalgae was almost in the order: Pyramidomonas sp. < Platymonas subcordiformis < Nannochloropsis oculata < Chlorella marine < Phaeodactylum tricomutum. Study of the QSAR (Quantitative Structure-Activity Relationship) between K OW and toxicity of CBs to marine algae showed good relationships between -log EC 50 and log K OW.

  11. Rapid Aggregation of Biofuel-Producing Algae by the Bacterium Bacillus sp. Strain RP1137

    PubMed Central

    Powell, Ryan J.

    2013-01-01

    Algal biofuels represent one of the most promising means of sustainably replacing liquid fuels. However, significant challenges remain before alga-based fuels become competitive with fossil fuels. One of the largest challenges is the ability to harvest the algae in an economical and low-energy manner. In this article, we describe the isolation of a bacterial strain, Bacillus sp. strain RP1137, which can rapidly aggregate several algae that are candidates for biofuel production, including a Nannochloropsis sp. This bacterium aggregates algae in a pH-dependent and reversible manner and retains its aggregation ability after paraformaldehyde fixation, opening the possibility for reuse of the cells. The optimal ratio of bacteria to algae is described, as is the robustness of aggregation at different salinities and temperatures. Aggregation is dependent on the presence of calcium or magnesium ions. The efficiency of aggregation of Nannochloropsis oceanica IMET1 is between 70 and 95% and is comparable to that obtained by other means of harvest; however, the rate of harvest is fast, with aggregates forming in 30 s. PMID:23892750

  12. 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. PMID:27174464

  13. 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

  14. Biomass and lipid enhancement in Chlorella sp. with emphasis on biodiesel quality assessment through detailed FAME signature.

    PubMed

    Shekh, Ajam Yakub; Shrivastava, Preeti; Gupta, Ankit; Krishnamurthi, Kannan; Devi, Sivanesan Saravana; Mudliar, Sandeep N

    2016-02-01

    In this study, the concentrations of MgSO4, salinity and light intensity were optimised for maximum biomass productivity and lipid content in Chlorella sp. Lipid synthesized at varied experimental conditions was also assessed in detail for biodiesel properties through FAME analysis. FAMEs mainly composed of C16:0, C16:1(9), C16:3(7, 10, 13), C18:0, C18:1(11), C18:2(9, 12), C18:3(9, 12, 15). The optimum biomass productivity (372.50mgL(-1)d(-1)) and lipid content (32.57%) was obtained at MgSO4-150ppm; salinity-12.5ppm, and light intensity-25μmolm(-2)s(-1). However, at this condition the cetane number, a major biodiesel property was not complying with worldwide biodiesel standard. Therefore, further optimisations were done to check the suitability of biodiesel fuel. The optimum biomass productivity (348.47mgL(-1)d(-1)) and lipid content (12.43%) with suitable biodiesel fuel properties was obtained at MgSO4-50ppm, salinity-25ppm and light intensity-100μmolm(-2)s(-1). The validation experiments confirmed the closeness of predicted and measured response values. PMID:26679050

  15. Improvement of biomass production by Chlorella sp. MJ 11/11 for use as a feedstock for biodiesel.

    PubMed

    Ghosh, Supratim; Roy, Shantonu; Das, Debabrata

    2015-04-01

    Algal biomass is gaining importance for biofuel production as it is rich in lipids. It becomes more significant when biomass is produced by capturing atmospheric greenhouse gas, CO2. In the present study, the effect of different physicochemical parameters were studied on the biomass and lipid productivity in Chlorella sp. MJ 11/11. The different parameters viz. initial pH, nitrate concentration, and phosphate concentration were optimized using single-parameter studies. The interactions between the parameters were determined statistically using the Box-Behnken design of optimization. The optimal values were decided by analyzing them with response surface methodology. The optimum levels of the parameters (pH 6.5, nitrate concentration 0.375 g L(-1), and phosphate concentration 0.375 mL L(-1)) yielded a maximum biomass concentration of 1.26 g L(-1) at a constant light intensity of 100 μmol m(-2) s(-1) and temperature of 30 °C. The effect of CO2 concentration on the biomass production was also investigated and was found to be a maximum of 4 g L(-1) at 5 % air-CO2 mixture (v/v). Maximum lipid content of 24.6 % (w/w) was observed at 2 % air-CO2 mixture (v/v). Fatty acid analyses of the obtained algal biomass suggested that they could be a suitable feedstock for biodiesel production. PMID:25690351

  16. High-efficiency homologous recombination in the oil-producing alga Nannochloropsis sp.

    PubMed

    Kilian, Oliver; Benemann, Christina S E; Niyogi, Krishna K; Vick, Bertrand

    2011-12-27

    Algae have reemerged as potential next-generation feedstocks for biofuels, but strain improvement and progress in algal biology research have been limited by the lack of advanced molecular tools for most eukaryotic microalgae. Here we describe the development of an efficient transformation method for Nannochloropsis sp., a fast-growing, unicellular alga capable of accumulating large amounts of oil. Moreover, we provide additional evidence that Nannochloropsis is haploid, and we demonstrate that insertion of transformation constructs into the nuclear genome can occur by high-efficiency homologous recombination. As examples, we generated knockouts of the genes encoding nitrate reductase and nitrite reductase, resulting in strains that were unable to grow on nitrate and nitrate/nitrite, respectively. The application of homologous recombination in this industrially relevant alga has the potential to rapidly advance algal functional genomics and biotechnology. PMID:22123974

  17. High-efficiency homologous recombination in the oil-producing alga Nannochloropsis sp.

    PubMed Central

    Kilian, Oliver; Benemann, Christina S. E.; Niyogi, Krishna K.; Vick, Bertrand

    2011-01-01

    Algae have reemerged as potential next-generation feedstocks for biofuels, but strain improvement and progress in algal biology research have been limited by the lack of advanced molecular tools for most eukaryotic microalgae. Here we describe the development of an efficient transformation method for Nannochloropsis sp., a fast-growing, unicellular alga capable of accumulating large amounts of oil. Moreover, we provide additional evidence that Nannochloropsis is haploid, and we demonstrate that insertion of transformation constructs into the nuclear genome can occur by high-efficiency homologous recombination. As examples, we generated knockouts of the genes encoding nitrate reductase and nitrite reductase, resulting in strains that were unable to grow on nitrate and nitrate/nitrite, respectively. The application of homologous recombination in this industrially relevant alga has the potential to rapidly advance algal functional genomics and biotechnology. PMID:22123974

  18. Acetyl-CoA synthetase is activated as part of the PDH-bypass in the oleaginous green alga Chlorella desiccata

    PubMed Central

    Avidan, Omri; Pick, Uri

    2015-01-01

    In a recent study, it has been shown that biosynthesis of triacylglycerol (TAG) in the oleaginous green alga Chlorella desiccata is preceded by a large increase in acetyl-coenzyme A (Ac-CoA) levels and by upregulation of plastidic pyruvate dehydrogenase (ptPDH). It was proposed that the capacity to accumulate high TAG critically depends on enhanced production of Ac-CoA. In this study, two alternative Ac-CoA producers—plastidic Ac-CoA synthase (ptACS) and ATP citrate lyase (ACL)—are shown to be upregulated prior to TAG accumulation under nitrogen deprivation in the oleaginous species C. desiccata, but not in the moderate TAG accumulators Dunaliella tertiolecta and Chlamydomonas reinhardtii. Measurements of endogenous acetate production and of radiolabelled acetate incorporation into lipids are consistent with the upregulation of ptACS, but suggest that its contribution to the overall TAG biosynthesis is negligible. Induction of ACS and production of endogenous acetate are correlated with activation of alcohol dehydrogenase, suggesting that the upregulation of ptACS is associated with activation of PDH-bypass in C. desiccata. It is proposed that activation of the PDH-bypass in C. desiccata is needed to enable a high rate of lipid biosynthesis under nitrogen deprivation by controlling the level of pyruvate reaching ptPHD and/or mtPDH. This may be an important parameter for massive TAG accumulation in microalgae. PMID:26357883

  19. THE EFFECT OF THE H ION CONCENTRATION ON THE AVAILABILITY OF IRON FOR CHLORELLA SP.

    PubMed

    Hopkins, E F; Wann, F B

    1925-11-20

    The data obtained in these experiments indicate clearly that unless the necessary precautions are taken to keep the iron of the culture medium in solution the results obtained by varying the H ion concentration will not represent the true effect of this factor on growth. The availability of iron in nutrient solutions has been the subject of numerous recent investigations and it is now known that iron is precipitated at the lower hydrogen ion concentrations, that the iron of certain iron salts is less likely to be precipitated than that of others, and that certain salts of organic acids tend to keep the iron in solution. In general, ferric citrate seems to be the most favorable source of iron. In addition to chemical precipitation, however, it is also possible for the iron to be removed by adsorption on an amorphous precipitate such as calcium phosphate. As this precipitate is frequently formed when nutrient solutions are made alkaline, this may account for the discordant results reported in the literature as to the availability of certain forms of iron. By omitting calcium from the culture solution iron can be maintained in a form available for growth in alkaline solutions by the addition of sodium citrate. In such solutions the maximum growth of Chlorella occurred at pH 7.5. The alkaline limit for growth has not been established as yet. In investigating the availability of iron at varying concentrations of the hydrogen ion, changes in the pH value of the solution during the course of an experiment should also be taken into account. This is especially important in unbuffered solutions. The differential absorption of the ions of ammonium salts may cause a marked increase in the hydrogen ion concentration, which in turn will cause an increase in the solubility of iron. In strongly buffered solutions as used in these experiments this effect is slight. PMID:19872244

  20. Evaluation of the Marine Algae Gracilaria salicornia and Sargassum sp. For the Biosorption of Cr (VI) from Aqueous Solutions

    NASA Astrophysics Data System (ADS)

    Shams Khorramabadi, Gh.; Darvishi Cheshmeh Soltani, R.

    In this study, the adsorption properties of two different marine algae (Gracilaria salicornia (red algae) and Sargassum sp. (brown algae) were investigated. Equilibrium isotherms were studied to evaluate the relative ability of the two algae to sequester Cr (VI) from aqueous solutions. The maximum biosorption capacity obtained was 45.959 mg g-1 for G. salicornia and 33.258 mg g-1 for Sargassum sp. at a solution pH of 4 and 50 mg L-1 initial chromium concentration. A significant fraction of the total Cr (VI) uptake was achieved within 60 min. Biosorbed chromium ions concentrations increased with increasing concentrations of biosorbents and increasing pH. The biosorption of Cr (VI) on G. salicornia and Sargassum sp. could best be described by the Langmuir model (R2>0.997 for Sargassum sp. and R2>0.999 for G. salicornia).

  1. Removal of trimethoprim, sulfamethoxazole, and triclosan by the green alga Nannochloris sp.

    PubMed

    Bai, Xuelian; Acharya, Kumud

    2016-09-01

    Trimethoprim (TMP), sulfamethoxazole (SMX), and triclosan (TCS) are widely used and continuously released into aquatic environments. Freshwater algae can be responsible for the uptake and transfer of the contaminants because they are a major food source for most aquatic organisms. This research applied incubation studies to evaluate the removal efficiency of TMP, SMX, and TCS by the green alga Nannochloris sp. The results showed that the hydrophilic antibiotics TMP and SMX remained in the algal culture at 100% and 68%, respectively, after 14days of incubation, and therefore were not significantly removed from the medium. However, the lipophilic antimicrobial TCS was significantly removed from the medium. Immediately after incubation began, 74% of TCS dissipated and 100% of TCS was removed after 7days of incubation. Additionally, over 42% of TCS was found associated with the algal cells throughout the incubation. The results demonstrate that the presence of Nannochloris sp. eliminated TCS in the aquatic system, but could not significantly remove the antibiotics TMP and SMX. The removal mechanisms of SMX and TCS were found to be different in the algal culture. Algae-promoted photolysis was the primary process for removing SMX and algae-mediated uptake played a major role in removing TCS. PMID:27179202

  2. Pyropia plicata sp. nov. (Bangiales, Rhodophyta): naming a common intertidal alga from New Zealand

    PubMed Central

    Nelson, Wendy A.

    2013-01-01

    Abstract A commonly found red alga of the upper intertidal zone of New Zealand rocky coasts is described for the first time as Pyropia plicata sp. nov. This species has been incorrectly known as Porphyra columbina Mont. (now Pyropia columbina (Mont.) W.A.Nelson) for many years. Pyropia plicata is widespread and common, and it is readily distinguished from other species of bladed Bangiales in New Zealand by its distinctive morphology, with pleated blades attached by a central rhizoidal holdfast. PMID:23794933

  3. The mechanisms whereby the green alga Chlorella ohadii, isolated from desert soil crust, exhibits unparalleled photodamage resistance.

    PubMed

    Treves, Haim; Raanan, Hagai; Kedem, Isaac; Murik, Omer; Keren, Nir; Zer, Hagit; Berkowicz, Simon M; Giordano, Mario; Norici, Alessandra; Shotland, Yoram; Ohad, Itzhak; Kaplan, Aaron

    2016-06-01

    Excess illumination damages the photosynthetic apparatus with severe implications with regard to plant productivity. Unlike model organisms, the growth of Chlorella ohadii, isolated from desert soil crust, remains unchanged and photosynthetic O2 evolution increases, even when exposed to irradiation twice that of maximal sunlight. Spectroscopic, biochemical and molecular approaches were applied to uncover the mechanisms involved. D1 protein in photosystem II (PSII) is barely degraded, even when exposed to antibiotics that prevent its replenishment. Measurements of various PSII parameters indicate that this complex functions differently from that in model organisms and suggest that C. ohadii activates a nonradiative electron recombination route which minimizes singlet oxygen formation and the resulting photoinhibition. The light-harvesting antenna is very small and carotene composition is hardly affected by excess illumination. Instead of succumbing to photodamage, C. ohadii activates additional means to dissipate excess light energy. It undergoes major structural, compositional and physiological changes, leading to a large rise in photosynthetic rate, lipids and carbohydrate content and inorganic carbon cycling. The ability of C. ohadii to avoid photodamage relies on a modified function of PSII and the dissipation of excess reductants downstream of the photosynthetic reaction centers. The biotechnological potential as a gene source for crop plant improvement is self-evident. PMID:26853530

  4. Photochemical Performance of the Acidophilic Red Alga Cyanidium sp. in a pH Gradient

    NASA Astrophysics Data System (ADS)

    Kvíderová, Jana

    2012-06-01

    The acidophilic red alga Cyanidium sp. is one of the dominant mat-forming species in the highly acidic waters of Río Tinto, Spain. The culture of Cyanidium sp., isolated from a microbial mat sample collected at Río Tinto, was exposed to 9 different pH conditions in a gradient from 0.5 to 5 for 24 h and its physiological status evaluated by variable chlorophyll a fluorescence kinetics measurements. Maximum quantum yield was determined after 30 min, 1 h, 2 h, 4 h, 6 h and 24 h of exposure after 15 min dark adaptation. The effect of pH on photochemical activity of Cyanidium sp. was observable as early as 30 min after exposure and the pattern remained stable or with only minor modifications for 24 h. The optimum pH ranged from 1.5 to 2.5. A steep decrease of the photochemical activity was observed at pH below 1 even after 30 min of exposure. Although the alga had tolerated the exposure to pH = 1 for at least 6 h, longer (24 h) exposure resulted in reduction of the photochemical activity. At pH above 2.5, the decline was more moderate and its negative effect on photochemistry was less severe. According to the fluorescence measurements, the red alga Cyanidium sp. is well-adapted to prevailing pH at its original locality at Río Tinto, i.e. pH of 1 to 3. The short-term survival in pH < 1.5 may be adaptation to rare exposures to such low pH in the field. The tolerance of pH above 3 could be caused by adaptation to the microenvironment of the inner parts of microbial mats in which Cyanidium sp. usually dominates and where higher pH could occur due to photosynthetic oxygen production.

  5. 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

  6. Effect of the Carbon Concentration, Blend Concentration, and Renewal Rate in the Growth Kinetic of Chlorella sp.

    PubMed Central

    Henrard, Adriano Arruda; da Rosa, Gabriel Martins; Moraes, Luiza; de Morais, Michele Greque; Costa, Jorge Alberto Vieira

    2014-01-01

    The microalgae cultivation can be used as alternative sources of food, in agriculture, residual water treatment, and biofuels production. Semicontinuous cultivation is little studied but is more cost-effective than the discontinuous (batch) cultivation. In the semicontinuous cultivation, the microalga is maintained in better concentration of nutrients and the photoinhibition by excessive cell is reduced. Thus, biomass productivity and biocompounds of interest, such as lipid productivity, may be higher than in batch cultivation. The objective of this study was to examine the influence of blend concentration, medium renewal rate, and concentration of sodium bicarbonate on the growth of Chlorella sp. during semicontinuous cultivation. The cultivation was carried out in Raceway type bioreactors of 6 L, for 40 d at 30°C, 41.6 µmol m−2 s−1, and a 12 h light/dark photoperiod. Maximum specific growth rate (0.149 d−1) and generating biomass (2.89 g L−1) were obtained when the blend concentration was 0.80 g L−1, the medium renewal rate was 40%, and NaHCO3 was 1.60 g L−1. The average productivity (0.091 g L−1 d−1) was achieved with 0.8 g L−1 of blend concentration and NaHCO3 concentration of 1.6 g L−1, independent of the medium renewal rate. PMID:25580453

  7. Air-Drying of Cells, the Novel Conditions for Stimulated Synthesis of Triacylglycerol in a Green Alga, Chlorella kessleri

    PubMed Central

    Minoda, Ayumi; Tsuzuki, Mikio; Sato, Norihiro

    2013-01-01

    Triacylglycerol is used for the production of commodities including food oils and biodiesel fuel. Microalgae can accumulate triacylglycerol under adverse environmental conditions such as nitrogen-starvation. This study explored the possibility of air-drying of green algal cells as a novel and simple protocol for enhancement of their triacylglycerol content. Chlorella kessleri cells were fixed on the surface of a glass fibre filter and then subjected to air-drying with light illumination. The dry cell weight, on a filter, increased by 2.7-fold in 96 h, the corresponding chlorophyll content ranging from 1.0 to 1.3-fold the initial one. Concomitantly, the triacylglycerol content remarkably increased to 70.3 mole% of fatty acids and 15.9% (w/w), relative to total fatty acids and dry cell weight, respectively, like in cells starved of nitrogen. Reduction of the stress of air-drying by placing the glass filter on a filter paper soaked in H2O lowered the fatty acid content of triacylglycerol to 26.4 mole% as to total fatty acids. Moreover, replacement of the H2O with culture medium further decreased the fatty acid content of triacylglycerol to 12.2 mole%. It thus seemed that severe dehydration is required for full induction of triacylglycerol synthesis, and that nutritional depletion as well as dehydration are crucial environmental factors. Meanwhile, air-drying of Chlamydomonas reinhardtii cells increased the triacylglycerol content to only 37.9 mole% of fatty acids and 4.8% (w/w), relative to total fatty acids and dry cell weight, respectively, and a marked decrease in the chlorophyll content, on a filter, of 33%. Air-drying thus has an impact on triacylglycerol synthesis in C. reinhardtii also, however, the effect is considerably limited, owing probably to instability of the photosynthetic machinery. This air-drying protocol could be useful for the development of a system for industrial production of triacylglycerol with appropriate selection of the algal species. PMID

  8. Some Nutritional Characteristics of a Naturally Occurring Alga (Microcystis sp.) in a Guatemalan Lake

    PubMed Central

    de la Fuente, Gabriel; Flores, Antonio; Molina, Mario R.; Almengor, Leticia; Bressani, Ricardo

    1977-01-01

    The nutritional characteristics of an alga (Microcystis sp.) that occurs naturally in a Guatemalan lake were determined. The sun-dried material proved to have a high protein content (55.6%) and to be a possible good source of calcium and phosphorus (1, 169.1 and 633.4 mg/100 mg, respectively). Amino acid analysis showed that total sulfur amino acids were the most deficient ones, giving a protein score of 42 to the material. The in vitro protein digestibility of the material was 69.5%. Biological trials demonstrated that when the material was offered as the only protein source, very low consumption and a high mortality rate were obtained whether or not the diet was supplemented with 0.4% dl-methionine. However, when the material supplied 25% of the total protein of a corn-algae diet, the protein quality of the cereal was significantly improved (P < 0.05). PMID:16345191

  9. 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. PMID:25500553

  10. Cultivation of Chlorella sp. using raw dairy wastewater for nutrient removal and biodiesel production: Characteristics comparison of indoor bench-scale and outdoor pilot-scale cultures.

    PubMed

    Lu, Weidong; Wang, Zhongming; Wang, Xuewei; Yuan, Zhenhong

    2015-09-01

    The biomass productivity and nutrient removal capacity of simultaneous Chlorella sp. cultivation for biodiesel production and nutrient removal in raw dairy wastewater (RDW) in indoor bench-scale and outdoor pilot-scale photobioreactors were compared. Results from the current work show that maximum biomass productivity in indoor bench-scale cultures can reach 260 mg L(-1) day(-1), compared to that of 110 mg L(-1) day(-1) in outdoor pilot-scale cultures. Maximum chemical oxygen demand (COD), total nitrogen (TN), and total phosphorous (TP) removal rate obtained in indoor conditions was 88.38, 38.34, and 2.03 mg L(-1) day(-1), respectively, this compared to 41.31, 6.58, and 2.74 mg L(-1) day(-1), respectively, for outdoor conditions. Finally, dominant fatty acids determined to be C16/C18 in outdoor pilot-scale cultures indicated great potential for scale up of Chlorella sp. cultivation in RDW for high quality biodiesel production coupling with RDW treatment. PMID:26056780

  11. Algae.

    PubMed

    Raven, John A; Giordano, Mario

    2014-07-01

    Algae frequently get a bad press. Pond slime is a problem in garden pools, algal blooms can produce toxins that incapacitate or kill animals and humans and even the term seaweed is pejorative - a weed being a plant growing in what humans consider to be the wrong place. Positive aspects of algae are generally less newsworthy - they are the basis of marine food webs, supporting fisheries and charismatic marine megafauna from albatrosses to whales, as well as consuming carbon dioxide and producing oxygen. Here we consider what algae are, their diversity in terms of evolutionary origin, size, shape and life cycles, and their role in the natural environment and in human affairs. PMID:25004359

  12. New α-glucosidase inhibitors from marine algae-derived Streptomyces sp. OUCMDZ-3434

    PubMed Central

    Chen, Zhengbo; Hao, Jiejie; Wang, Liping; Wang, Yi; Kong, Fandong; Zhu, Weiming

    2016-01-01

    Wailupemycins H (1) and I (2) with a new skeleton coupled two 6-(2-phenylnaphthalene-1-yl)pyrane-2-one nuclei to a –CH2– linkage were identified from the culture of Streptomyces sp. OUCMDZ-3434 associated with the marine algae, Enteromorpha prolifera. Compounds 1 and 2 are two new α-glucosidase inhibitors with the Ki/IC50 values of 16.8/19.7 and 6.0/8.3 μM, respectively. In addition, the absolute configurations of wailupemycins D (3) and E (4) are also resolved in this paper for the first time. PMID:26822662

  13. Combined toxicity of two crystalline phases (anatase and rutile) of Titania nanoparticles towards freshwater microalgae: Chlorella sp.

    PubMed

    Iswarya, V; Bhuvaneshwari, M; Alex, Sruthi Ann; Iyer, Siddharth; Chaudhuri, Gouri; Chandrasekaran, Prathna Thanjavur; Bhalerao, Gopalkrishna M; Chakravarty, Sujoy; Raichur, Ashok M; Chandrasekaran, N; Mukherjee, Amitava

    2015-04-01

    In view of the increasing usage of anatase and rutile crystalline phases of titania NPs in the consumer products, their entry into the aquatic environment may pose a serious risk to the ecosystem. In the present study, the possible toxic impact of anatase and rutile nanoparticles (individually and in binary mixture) was investigated using freshwater microalgae, Chlorella sp. at low exposure concentrations (0.25, 0.5 and 1mg/L) in freshwater medium under UV irradiation. Reduction of cell viability as well as a reduction in chlorophyll content were observed due to the presence of NPs. An antagonistic effect was noted at certain concentrations of binary mixture such as (0.25, 0.25), (0.25, 0.5), and (0.5, 0.5) mg/L, and an additive effect for the other combinations, (0.25, 1), (0.5, 0.25), (0.5, 1), (1, 0.25), (1, 0.5), and (1, 1) mg/L. The hydrodynamic size analyses in the test medium revealed that rutile NPs were more stable in lake water than the anatase and binary mixtures [at 6h, the sizes of anatase (1mg/L), rutile NPs (1mg/L), and binary mixture (1, 1mg/L) were 948.83±35.01nm, 555.74±19.93nm, and 1620.24±237.87nm, respectively]. The generation of oxidative stress was found to be strongly dependent on the crystallinity of the nanoparticles. The transmission electron microscopic images revealed damages in the nucleus and cell membrane of algal cells due to the interaction of anatase NPs, whereas rutile NPs were found to cause chloroplast and internal organelle damages. Mis-shaped chloroplasts, lack of nucleus, and starch-pyrenoid complex were noted in binary-treated cells. The findings from the current study may facilitate the environmental risk assessment of titania NPs in an aquatic ecosystem. PMID:25703177

  14. Rapid method for DNA isolation from a tough cell wall green alga Tetraspora sp. CU2551.

    PubMed

    Maneeruttanarungroj, Cherdsak; Incharoensakdi, Aran

    2016-06-01

    Genetic studies are important to understand the complex biological system of various organisms. Some eukaryotic green organisms have tough cell wall which precludes the efficient extraction of the genetic materials. Here, we developed the method for simple and rapid isolation of high quality DNA from a green alga Tetraspora sp. CU2551. The cell homogenization procedures were combined with physical force plus heat treatment to disrupt the cell envelope of Tetraspora sp. CU2551. Without protease treatment, vortexing with glass bead for 30-105 s at 70 °C led to the isolation of a high purity DNA which was suitable for downstream process. The improved method was successfully developed and could be applied for the rapid isolation of DNA from other unicellular and filamentous green microalgal strains. PMID:27116965

  15. Cellular Fe-hydroxides and heavy metal sorption in Euglena sp. (algae): implications for biomineralization

    SciTech Connect

    Mann, H.; Beveridge, T.O. Fyfe, W.S.; Tazaki, K.

    1985-01-01

    STEM imagery and electron diffraction patterns of Euglena sp. reveal pronounced intra and cellular-membrane aggregates of Fe-hydroxides (some lepidocrocite), in natural communities from tailings waters, Elliott Lake, Ontario. Pure isolates of Euglena sp. contain 40-70% Fe by dry weight and in addition average Al 28,000 ppm, Sr 150, Ba 40, Zn 150, Mn 250, Ni 120, Pb 1600, Th 70, Cu 200 and U 180. In tailings waters, Fe solute concentrations average 560 ppm and U 50 ppb. Concentration factors for Fe, Ba, Zn, Mn, Ti, V, Ni, Pb, Cr, Ag, Co and Cu in algae referenced to average world river waters are greater than or equal to 10/sup 6/. These results endorse the premise that microorganisms mediate transfer of many solutes between the hydrosphere and sedimentary regime.

  16. Defluviitalea phaphyphila sp. nov., a Novel Thermophilic Bacterium That Degrades Brown Algae

    PubMed Central

    Ji, Shi-Qi; Wang, Bing; Lu, Ming

    2015-01-01

    Brown algae are one of the largest groups of oceanic primary producers for CO2 removal and carbon sinks for coastal regions. However, the mechanism for brown alga assimilation remains largely unknown in thermophilic microorganisms. In this work, a thermophilic alginolytic community was enriched from coastal sediment, from which an obligate anaerobic and thermophilic bacterial strain, designated Alg1, was isolated. Alg1 shared a 16S rRNA gene identity of 94.6% with Defluviitalea saccharophila LIND6LT2T. Phenotypic, chemotaxonomic, and phylogenetic studies suggested strain Alg1 represented a novel species of the genus Defluviitalea, for which the name Defluviitalea phaphyphila sp. nov. is proposed. Alg1 exhibited an intriguing ability to convert carbohydrates of brown algae, including alginate, laminarin, and mannitol, to ethanol and acetic acid. Three gene clusters participating in this process were predicted to be in the genome, and candidate enzymes were successfully expressed, purified, and characterized. Six alginate lyases were demonstrated to synergistically deconstruct alginate into unsaturated monosaccharide, followed by one uronic acid reductase and two 2-keto-3-deoxy-d-gluconate (KDG) kinases to produce pyruvate. A nonclassical mannitol 1-phosphate dehydrogenase, catalyzing d-mannitol 1-phosphate to fructose 1-phosphate in the presence of NAD+, and one laminarase also were disclosed. This work revealed that a thermophilic brown alga-decomposing system containing numerous novel thermophilic alginate lyases and a unique mannitol 1-phosphate dehydrogenase was adopted by the natural ethanologenic strain Alg1 during the process of evolution in hostile habitats. PMID:26590273

  17. Defluviitalea phaphyphila sp. nov., a Novel Thermophilic Bacterium That Degrades Brown Algae.

    PubMed

    Ji, Shi-Qi; Wang, Bing; Lu, Ming; Li, Fu-Li

    2016-02-01

    Brown algae are one of the largest groups of oceanic primary producers for CO2 removal and carbon sinks for coastal regions. However, the mechanism for brown alga assimilation remains largely unknown in thermophilic microorganisms. In this work, a thermophilic alginolytic community was enriched from coastal sediment, from which an obligate anaerobic and thermophilic bacterial strain, designated Alg1, was isolated. Alg1 shared a 16S rRNA gene identity of 94.6% with Defluviitalea saccharophila LIND6LT2(T). Phenotypic, chemotaxonomic, and phylogenetic studies suggested strain Alg1 represented a novel species of the genus Defluviitalea, for which the name Defluviitalea phaphyphila sp. nov. is proposed. Alg1 exhibited an intriguing ability to convert carbohydrates of brown algae, including alginate, laminarin, and mannitol, to ethanol and acetic acid. Three gene clusters participating in this process were predicted to be in the genome, and candidate enzymes were successfully expressed, purified, and characterized. Six alginate lyases were demonstrated to synergistically deconstruct alginate into unsaturated monosaccharide, followed by one uronic acid reductase and two 2-keto-3-deoxy-d-gluconate (KDG) kinases to produce pyruvate. A nonclassical mannitol 1-phosphate dehydrogenase, catalyzing D-mannitol 1-phosphate to fructose 1-phosphate in the presence of NAD(+), and one laminarase also were disclosed. This work revealed that a thermophilic brown alga-decomposing system containing numerous novel thermophilic alginate lyases and a unique mannitol 1-phosphate dehydrogenase was adopted by the natural ethanologenic strain Alg1 during the process of evolution in hostile habitats. PMID:26590273

  18. Ozonation of the marine dinoflagellate alga Amphidinium sp.--implications for ballast water disinfection.

    PubMed

    Oemcke, D J; Hans van Leeuwen, J

    2005-12-01

    Ozone has been investigated for its potential to remove marine dinoflagellate algae from ships' ballast water. Dinoflagellate algae, Amphidinium sp. isolated from the Great Barrier Reef, Townsville, Australia were used as indicators since these produce a type of cyst that is difficult to inactivate, but are relatively easy to culture. The ozonation experiments have demonstrated a high ozone demand for inactivation of the algal cultures, which increases as the culture ages. The main ozone demand in seawater is due to its reaction with bromide to form bromine compounds. The non-bromide ozone demand has been estimated by measuring the residuals produced after various doses of ozone. The Amphidinium sp. show an unexpected response to both ozonation and bromination, with an instantaneous inactivation of the organisms for all doses that produced an oxidant residual in the seawater, followed by an effect of the disinfection residual. The standard design procedure of comparing Ct will not be effective for predicting the response of the organism to varying dose, C, and contact time, t, and a plot of ozone produced oxidant residual against organism inactivation for various contact times is proposed for design purposes. High doses of ozone (5-11 mg/L) and up to 6h of residual contact were required for a 4-log inactivation of the Amphidinium sp. Ozonation is likely to be a difficult technology to implement for organisms with this ozone requirement in combination with characteristics of ballast tanks, which contain areas of sediments high in detritus and areas of corrosion. PMID:16289281

  19. 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. PMID:25600216

  20. Building a better mousetrap I: using Design of Experiments with unconfounded ions to discover superior media for growth and lipid production by Chlorella sp. EN1234.

    PubMed

    Hallenbeck, Patrick C; Grogger, Melanie; Mraz, Megan; Veverka, Donald

    2015-05-01

    An unconfounded Scheffe Mix approach was used to probe important ions and their interactions in supporting biomass and lipid production by Chlorella sp. EN1234. Six major cations and anions; NH4(+), NO3(-), Na(+), K(+) PO4(-) and Cl(-) were examined. Piepel plots and RSM analysis showed that in a number of cases, the major media anions PO4(-) and Cl(-) negatively influence final cell densities, and that maximal cell density is obtained with nitrate over ammonium, with an optimal effect when mixed with equal molar potassium. As well, although it is commonly assumed that lipid content increases in nitrogen deficient media, here little correlation between nitrogen content and total lipid content was found with mixtures that supported high lipid productivity. Thus these mixtures define the composition space within which further R&D might produce the best trade-off between total biomass production and high cellular lipid content. PMID:25465787

  1. Total lipid production of the green alga Nannochloropsis sp. QII under different nitrogen regimes

    SciTech Connect

    Suen, Yu.; Hubbard, J.S.; Holzer, G.; Tornabene, T.G.

    1987-06-01

    The green alga Nannochloropsis sp. QII was cultivated in media with sufficient and growth-limiting levels of nitrogen (nitrate). Nitrogen deficiency promoted lipid synthesis yielding cells with lipids comprising 55% of the biomass. The major lipids were triacylglycerols (79%), polar lipids (9%) and hydrocarbons (2.5%). The polar lipids consisted of a broad range of phospholipids, glycolipids and sulfolipids. Other lipids identified were pigments, free fatty acids, saponifiable and unsaponifiable sterol derivatives, various glycerides, a family of alkyl-1, 4-dioxane derivatives and a series of alkyl- and hydroxy-alkyl-dimethyl-acetals. Experiments in which /sup 14/CO/sub 2/ was provided at different times in the growth cycle demonstrated that enhanced lipid biosynthesis at low nitrogen levels resulted principally from de novo CO/sub 2/ fixation.

  2. Sphacelaria lacustris sp. nov. , a freshwater brown alga from Lake Michigan

    SciTech Connect

    Schloesser, R.E.; Blum, J.L.

    1980-06-01

    The growth, reproduction and ultrasturcture of a new freshwater phaeophyte, Sphacelaria lacustris sp. nov., are described. The plant occurs as a minute calcified thallus at 5 to 15 m depth along the western shoreline of Lake Michigan. Both freshly collected and laboratory grown plants show apical growth of erect and basal filaments, intermittent longitudinal divisions in filament segments, vegetative reproduction by propagules, numerous parietal chloroplasts and an absence of pyrenoids, characteristics of Sphacelaria. This material is separated from the only other freshwater species in the genus (S. fluviatilis Jao) at least by differences in longitudinal septation, in branching, in its propagules and in general aspect. Between this plant and marine brown algae there are essential similarities of ultrastructure of cell wall and pores, chloroplasts, mitochondria, nucleus and the production/excretion of physodes.

  3. Platinum anniversary: virus and lichen alga together more than 70 years.

    PubMed

    Petrzik, Karel; Vondrák, Jan; Kvíderová, Jana; Lukavský, Jaromír

    2015-01-01

    Trebouxia aggregata (Archibald) Gärtner (phylum Chlorophyta, family Trebouxiaceae), a lichen symbiotic alga, has been identified as host of the well-known herbaceous plant virus Cauliflower mosaic virus (CaMV, family Caulimoviridae). The alga had been isolated from Xanthoria parietina more than 70 years ago and has been maintained in a collection since that time. The CaMV detected in this collection entry has now been completely sequenced. The virus from T. aggregata is mechanically transmissible to a herbaceous host and induces disease symptoms there. Its genome differs by 173 nt from the closest European CaMV-D/H isolate from cauliflower. No site under positive selection was found on the CaMV genome from T. aggregata. We therefore assume that the virus's presence in this alga was not sufficiently long to fix any specific changes in its genome. Apart from this symbiotic alga, CaMV capsid protein sequences were amplified from many other non-symbiotic algae species maintained in a collection (e.g., Oonephris obesa, Elliptochloris sp., Microthamnion kuetzingianum, Chlorella vulgaris, Pseudococcomyxa sp.). CaMV-free Chlorella vulgaris was treated with CaMV to establish virus infection. The virus was still detected there after five passages. The virus infection is morphologically symptomless on Chlorella algae and the photosynthesis activity is slightly decreased in comparison to CaMV-free alga culture. This is the first proof as to the natural presence of CaMV in algae and the first demonstration of algae being artificially infected with this virus. PMID:25789995

  4. Platinum Anniversary: Virus and Lichen Alga Together More than 70 Years

    PubMed Central

    Petrzik, Karel; Vondrák, Jan; Kvíderová, Jana; Lukavský, Jaromír

    2015-01-01

    Trebouxia aggregata (Archibald) Gärtner (phylum Chlorophyta, family Trebouxiaceae), a lichen symbiotic alga, has been identified as host of the well-known herbaceous plant virus Cauliflower mosaic virus (CaMV, family Caulimoviridae). The alga had been isolated from Xanthoria parietina more than 70 years ago and has been maintained in a collection since that time. The CaMV detected in this collection entry has now been completely sequenced. The virus from T. aggregata is mechanically transmissible to a herbaceous host and induces disease symptoms there. Its genome differs by 173 nt from the closest European CaMV-D/H isolate from cauliflower. No site under positive selection was found on the CaMV genome from T. aggregata. We therefore assume that the virus’s presence in this alga was not sufficiently long to fix any specific changes in its genome. Apart from this symbiotic alga, CaMV capsid protein sequences were amplified from many other non-symbiotic algae species maintained in a collection (e.g., Oonephris obesa, Elliptochloris sp., Microthamnion kuetzingianum, Chlorella vulgaris, Pseudococcomyxa sp.). CaMV-free Chlorella vulgaris was treated with CaMV to establish virus infection. The virus was still detected there after five passages. The virus infection is morphologically symptomless on Chlorella algae and the photosynthesis activity is slightly decreased in comparison to CaMV-free alga culture. This is the first proof as to the natural presence of CaMV in algae and the first demonstration of algae being artificially infected with this virus. PMID:25789995

  5. Biomass production and removal of ammonium and phosphate by Chlorella sp. in sludge liquor at natural light and different levels of temperature control.

    PubMed

    Åkerström, Anette M; Mortensen, Leiv M; Rusten, Bjørn; Gislerød, Hans Ragnar

    2016-01-01

    Microalgae cultivation for biomass production and nutrient removal implies the use of natural light and minimal control of the temperature for obtaining a low cost production. The aim of this study was to quantify the effect of temperature control at natural light on biomass productivity and removal of NH4-N and PO4-P of a mesophilic strain of Chlorella. Chlorella sp. was grown in reject water of anaerobically digested municipal sludge, sludge liquor, inside a greenhouse compartment (Ås, Norway, 59°N) using batch cultures (300 mL). Five experiments were conducted from May to September, and effects of different levels of temperature control and diurnal variations were investigated. The highest biomass productivities (0.45 g L(-1) day(-1)) in the linear growth phase were obtained at daily light integrals ≥12 mol day(-1) m(-2). Results showed that the average temperature was of more importance than the night or day temperature range. At average temperatures <22 °C for cultures with no temperature control, the productivity decreased by 23 and 39 % compared to cultures with full temperature control (24-25 °C). In one experiment, the productivity was reduced at no temperature control due to prolonged high daytime temperatures (>32 °C) and were followed by a lower NH4-N removal rate. Otherwise, temperature had little effect on NH4-N removal. The level of temperature control did not affect removal of PO4-P. Cellular starch content varied from ~15-38 % in the evening and was generally lower at no temperature control. In the morning the starch content was reduced to ~4-12 % with no difference between the different levels of temperature control. (~4-12 %). PMID:27350913

  6. BIODIVERSITY OF CORALLINE ALGAE IN THE NORTHEASTERN ATLANTIC INCLUDING CORALLINA CAESPITOSA SP. NOV. (CORALLINOIDEAE, RHODOPHYTA)(1).

    PubMed

    Walker, Rachel H; Brodie, Juliet; Russell, Stephen; Irvine, Linda M; Orfanidis, Sotiris

    2009-02-01

    The Corallinoideae (Corallinaceae) is represented in the northeastern Atlantic by Corallina officinalis L.; Corallina elongata J. Ellis et Sol.; Haliptilon squamatum (L.) H. W. Johans., L. M. Irvine et A. M. Webster; and Jania rubens (L.) J. V. Lamour. The delimitation of these geniculate coralline red algae is based primarily on morphological characters. Molecular analysis based on cox1 and 18S rRNA gene phylogenies supported the division of the Corallinoideae into the tribes Janieae and Corallineae. Within the Janieae, a sequence difference of 46-48 bp (8.6%-8.9%) between specimens of H. squamatum and J. rubens in the cox1 phylogeny leads us to conclude that they are congeneric. J. rubens var. rubens and J. rubens var. corniculata (L.) Yendo clustered together in both phylogenies, suggesting that for those genes, there was no genetic basis for the morphological variation. Within the Corallineae, it appears that in some regions, the name C. elongata has been misapplied. C. officinalis samples formed two clusters that differed by 45-54 bp (8.4%-10.0%), indicating species-level divergence, and morphological differences were sufficient to define two species. One of these clusters was consistent with the morphology of the type specimen of C. officinalis (LINN 1293.9). The other species cluster is therefore described here as Corallina caespitosa sp. nov. This study has demonstrated that there is a clear need for a revision of the genus Corallina to determine the extent of "pseudocryptic" diversity in this group of red algae. PMID:27033664

  7. Molecular and biochemical characterization of mannitol-1-phosphate dehydrogenase from the model brown alga Ectocarpus sp.

    PubMed

    Bonin, Patricia; Groisillier, Agnès; Raimbault, Alice; Guibert, Anaïs; Boyen, Catherine; Tonon, Thierry

    2015-09-01

    The sugar alcohol mannitol is important in the food, pharmaceutical, medical and chemical industries. It is one of the most commonly occurring polyols in nature, with the exception of Archaea and animals. It has a range of physiological roles, including as carbon storage, compatible solute, and osmolyte. Mannitol is present in large amounts in brown algae, where its synthesis involved two steps: a mannitol-1-phosphate dehydrogenase (M1PDH) catalyzes a reversible reaction between fructose-6-phosphate (F6P) and mannitol-1-phosphate (M1P) (EC 1.1.1.17), and a mannitol-1-phosphatase hydrolyzes M1P to mannitol (EC 3.1.3.22). Analysis of the model brown alga Ectocarpus sp. genome provided three candidate genes for M1PDH activities. We report here the sequence analysis of Ectocarpus M1PDHs (EsM1PDHs), and the biochemical characterization of the recombinant catalytic domain of EsM1PDH1 (EsM1PDH1cat). Ectocarpus M1PDHs are representatives of a new type of modular M1PDHs among the polyol-specific long-chain dehydrogenases/reductases (PSLDRs). The N-terminal domain of EsM1PDH1 was not necessary for enzymatic activity. Determination of kinetic parameters indicated that EsM1PDH1cat displayed higher catalytic efficiency for F6P reduction compared to M1P oxidation. Both activities were influenced by NaCl concentration and inhibited by the thioreactive compound pHMB. These observations were completed by measurement of endogenous M1PDH activity and of EsM1PDH gene expression during one diurnal cycle. No significant changes in enzyme activity were monitored between day and night, although transcription of two out of three genes was altered, suggesting different levels of regulation for this key metabolic pathway in brown algal physiology. PMID:26232554

  8. 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

  9. 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

  10. 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. PMID:26840425

  11. Cyanobactericidal effect of Rhodococcus sp. isolated from eutrophic lake on Microcystis sp.

    PubMed

    Lee, Young-Ki; Ahn, Chi-Yong; Kim, Hee-Sik; Oh, Hee-Mock

    2010-11-01

    A bacterium, which was observed in all cultivations of Microcystis sp., was isolated and designated as Rhodococcus sp. KWR2. The growth of bloom-forming cyanobacteria, including four strains of Microcystis aeruginosa and Anabaena variabilis, was suppressed by up to 75-88% by 2% (v/v) culture broth of KWR2 after 5 days. But KWR2 did not inhibit eukaryotic algae, Chlorella vulgaris and Scenedesmus sp. An extracellular algicidal substance produced by KWR2 showed a cyanobactericidal activity of 94% and was water-soluble with a molecular weight of lower than 8 kDa. PMID:20640876

  12. Antioxidant, cytotoxic, antitumor, and protective DNA damage metabolites from the red sea brown alga Sargassum sp

    PubMed Central

    Ayyad, Seif-Eldin N.; Ezmirly, Saleh T.; Basaif, Salim A.; Alarif, Walied M.; Badria, Adel F.; Badria, Farid A.

    2011-01-01

    Background: Macroalgae can be viewed as a potential antioxidant and anti-inflammatory sources owing to their capability of producing compounds for its protection from environmental factors such as heat, pollution, stress, oxygen concentration, and UV radiations. Objective: To isolate major compounds which are mainly responsible for the pharmacological activity of brown alga under investigation, Sargassum sp. Materials and Methods: Algal material was air dried, extracted with a mixture of organic solvents, and fractionated with different adsorbents. The structures of obtained pure compounds were elucidated with different spectroscopic techniques, and two pure materials were tested for protection of DNA from damage, antioxidant, antitumor, and cytotoxicity. Results: Four pure compounds were obtained, of which fucosterol (1) and fucoxanthin (4) were tested; it was found that fucoxanthin has strong antioxidant and cytotoxicity against breast cancer (MCF-7) with IC50 = 11.5 μg/ml. Conclusion: The naturally highly conjugated safe compound fucoxanthin could be used as antioxidant and as an antitumor compound. PMID:22022163

  13. Amylibacter ulvae sp. nov., a new alphaproteobacterium isolated from the Pacific green alga Ulva fenestrata.

    PubMed

    Nedashkovskaya, Olga I; Kukhlevskiy, Andrey D; Zhukova, Natalia V; Kim, Seung Bum

    2016-04-01

    A strictly aerobic, Gram-stain-negative, rod-shaped and non-motile bacterium, designated strain 6Alg 255(T), was isolated from the green alga Ulva fenestrata. Phylogenetic analysis based on 16S rRNA gene sequencing revealed that the novel strain affiliated to the family Rhodobacteraceae of the class Alphaproteobacteria being most closely related to Amylibacter marinus LMG 28364(T) with 16S rRNA gene sequence similarity of 97.2 %. Strain 6Alg 255(T) grew with 0.5-6.0 % NaCl and at 4-33 °C, hydrolysed aesculin, casein, gelatin and urea. The DNA G + C content was 50.4 mol%. The prevalent fatty acids were C18:1 ω7c and C16:0. The polar lipid profile was characterized by the presence of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and unidentified aminolipid. The major respiratory quinone was Q-10. The significant molecular distinctiveness between the novel isolate and its nearest neighbour was strongly supported by the differences in physiological and biochemical tests. Therefore, strain 6Alg 255(T) represents a novel species of the genus Amylibacter, for which the name Amylibacter ulvae sp. nov. is proposed. The type strain is 6Alg 255(T) (=KCTC 32465(T) = KMM 6515(T)). PMID:26762377

  14. A Comparative biochemical study on two marine endophytes, Bacterium SRCnm and Bacillus sp. JS, Isolated from red sea algae.

    PubMed

    Ahmed, Eman Fadl; Hassan, Hossam Mokhtar; Rateb, Mostafa Ezzat; Abdel-Wahab, Noha; Sameer, Somayah; Aly Taie, Hanan Anwar; Abdel-Hameed, Mohammed Sayed; Hammouda, Ola

    2016-01-01

    Two marine endophytic bacteria were isolated from the Red Sea algae; a red alga; Acanthophora dendroides and the brown alga Sargassum sabrepandum. The isolates were identified based on their 16SrRNA sequences as Bacterium SRCnm and Bacillus sp. JS. The objective of this study was to investigate the potential anti-microbial and antioxidant activities of the extracts of the isolated bacteria grown in different nutrient conditions. Compared to amoxicillin (25μg/disk) and erythromycin (15μg/disk), the extracts of Bacterium SRCn min media II, III, IV and V were potent inhibitors of the gram-positive bacterium Sarcina maxima even at low concentrations. Also, the multidrug resistant Staphylococcus aureus(MRSA) was more sensitive to the metabolites produced in medium (II) of the same endophyte than erythromycin (15μg/disk). A moderate activity of the Bacillus sp. JS extracts of media I and II was obtained against the same pathogen. The total compounds (500ug/ml) of both isolated endophytes showed moderate antioxidant activities (48.9% and 46.1%, respectively). LC/MS analysis of the bacterial extracts was carried out to investigate the likely natural products produced. Cyclo(D-cis-Hyp-L-Leu), dihydrosphingosine and 2-Amino-1,3-hexadecanediol were identified in the fermentation medium of Bacterium SRCnm, whereas cyclo (D-Pro-L-Tyr) and cyclo (L-Leu-L-Pro) were the suggested compounds of Bacillus sp. JS. PMID:26826831

  15. 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.

  16. In-field experimental verification of cultivation of microalgae Chlorella sp. using the flue gas from a cogeneration unit as a source of carbon dioxide.

    PubMed

    Kastánek, Frantisek; Sabata, Stanislav; Solcová, Olga; Maléterová, Ywette; Kastánek, Petr; Brányiková, Irena; Kuthan, Karel; Zachleder, Vilém

    2010-11-01

    A complex treatment of agricultural waste including the following major steps: anaerobic fermentation of suitable waste, cogeneration of the obtained biogas and growth of microalgae consuming the CO(2) from biogas and flue gas was verified under field conditions in a pilot-scale photobioreactor. The growth kinetics of microalgae Chlorella sp. consuming mixture of air and carbon dioxide (2% (v/v) of CO(2)), or flue gas (8-10% (v/v) of CO(2)) was investigated. The results obtained in the pilot photobioreactor were compared with results previously measured in laboratory photobioreactors. The field tests were performed in a pilot-scale outdoor solar-bubbled photobioreactor located at a biogas station. The pilot-scale photobioreactor was in the shape of a flat and narrow vertical prism with a volume of 300 L. The microalgae growth rates were correlated with empirical formulas. Laboratory analyses of the produced microalgae confirmed that it meets the strict EU criteria for relevant contaminants level in foodstuffs. Utilization of flue gases from cogeneration therefore was not found to be detrimental to the quality of microalgal biomass, and may be used in these types of bioreactors. PMID:20671004

  17. Evaluation of indigenous microalgal isolate Chlorella sp. FC2 IITG as a cell factory for biodiesel production and scale up in outdoor conditions.

    PubMed

    Muthuraj, Muthusivaramapandian; Kumar, Vikram; Palabhanvi, Basavaraj; Das, Debasish

    2014-03-01

    The present study reports evaluation of an indigenous microalgal isolate Chlorella sp. FC2 IITG as a potential candidate for biodiesel production. Characterization of the strain was performed under photoautotrophic, heterotrophic, and mixotrophic cultivation conditions. Further, an open-pond cultivation of the strain under outdoor conditions was demonstrated to evaluate growth performance and lipid productivity under fluctuating environmental parameters and in the presence of potential contaminants. The key findings were: (1) the difference in cultivation conditions resulted in significant variation in the biomass productivity (73-114 mg l⁻¹ day⁻¹) and total lipid productivity (35.02-50.42 mg l⁻¹ day⁻¹) of the strain; (2) nitrate and phosphate starvation were found to be the triggers for lipid accumulation in the cell mass; (3) open-pond cultivation of the strain under outdoor conditions resulted in biomass productivity of 44 mg l⁻¹ day⁻¹ and total lipid productivity of 10.7 mg l⁻¹ day⁻¹; (4) a maximum detectable bacterial contamination of 7 % of the total number of cells was recorded in an open-pond system; and (5) fatty acid profiling revealed abundance of palmitic acid (C16:0), oleic acid (C18:1) and linoleic acid (C18:2), which are considered to be the key elements for suitable quality biodiesel. PMID:24445403

  18. Winogradskyella eckloniae sp. nov., a marine bacterium isolated from the brown alga Ecklonia cava.

    PubMed

    Kim, Ji-Young; Park, So-Hyun; Seo, Ga-Young; Kim, Young-Ju; Oh, Duck-Chul

    2015-09-01

    A novel bacterial strain, designated EC29(T), was isolated from the brown alga Ecklonia cava collected on Jeju Island, Republic of Korea. Cells of strain EC29(T) were Gram-stain-negative, aerobic, rod-shaped and motile by gliding. Growth was observed at 10-30 °C (optimum, 20-25 °C), at pH 6.0-9.5 (optimum, pH 7.5) and in the presence of 1-5% (w/v) NaCl. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that the strain belonged to the genus Winogradskyella. Strain EC29(T) exhibited the highest 16S rRNA gene sequence similarities, of 96.5-97.8%, to the type strains of Winogradskyella pulchriflava EM106(T), Winogradskyella echinorum KMM 6211(T) and Winogradskyella ulvae KMM 6390(T). Strain EC29(T) exhibited < 27% DNA-DNA relatedness with Winogradskyella pulchriflava EM106(T) and Winogradskyella echinorum KMM 6211(T). The predominant fatty acids of strain EC29(T) were iso-C15 : 0, iso-C15 : 1 G, C15 : 0, iso-C17 : 0 3-OH, iso-C15 : 0 3-OH and anteiso-C15 : 0. The DNA G+C content was 31.1 mol% and the major respiratory quinone was menaquinone-6 (MK-6). Based on a polyphasic study, strain EC29(T) is considered to represent a novel species of the genus Winogradskyella, for which the name Winogradskyella eckloniae sp. nov. is proposed. The type strain is EC29(T) ( = KCTC 32172(T) = JCM 18703(T)). PMID:25979633

  19. Flavobacterium jejuensis sp. nov., isolated from marine brown alga Ecklonia cava.

    PubMed

    Park, So-Hyun; Kim, Ji-Young; Kim, Young-Ju; Heo, Moon-Soo

    2015-11-01

    A bacterial strain, designated EC11(T) was isolated from brown alga Ecklonia cava collected from Jeju Island, Korea. EC11(T) was identified as a Gram-negative, rod-shaped and yellow-pigmented bacterial strain. The strain EC11(T) grew over a temperature range of 10 °C to 30 °C (optimally at 25 °C), and a pH range of 6.0-10.5 (optimally at pH 7.5). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain EC11(T) belongs to the genus Flavobacterium. Strain EC11(T) shared close similarity with Flavobacterium jumunjinense HME7102(T) (96.4%), Flavobacterium dongtanense LW30(T) (95.8%), Flavobacterium haoranii LQY-7(T) (95.3%), and Flavobacterium urocaniciphilum (95.1%). The major fatty acids (> 5%) were iso-C17:0 3-OH (22.4%), iso-C15:0 3-OH (19.0%), C15:0 (12.4%), summed feature 3 (comprising C16:1 ω7c/ C16:1 ω6c; 9.78%), iso-C15:1 G (9.6%), and iso-C16:0 3-OH (9.0%). The DNA G+C content was 28.1 mol% and the strain contained MK-6 as the predominant menaquinone. The major polar lipids were phosphatidylethanolamine, two unknown aminolipids and three unknown polar lipids. Based on phenotypic, chemotaxonomic and phylogenetic analysis, strain EC11T represents a novel species of the Flavobacterium genus, for which the name Flavobacterium jejuensis sp. nov. is proposed. The type strain of F. jejuensis is EC11(T) (=KCTC 42149(T) = JCM 30735(T)). PMID:26502959

  20. Shewanella algicola sp. nov., a marine bacterium isolated from brown algae.

    PubMed

    Kim, Ji-Young; Yoo, Han-Su; Lee, Dong-Heon; Park, So-Hyun; Kim, Young-Ju; Oh, Duck-Chul

    2016-06-01

    A Gram-stain-negative, aerobic, rod-shaped bacterium motile by means of a single polar flagella, strain ST-6T, was isolated from a brown alga (Sargassum thunbergii) collected in Jeju, Republic of Korea. Strain ST-6T was psychrotolerant, growing at 4-30 °C (optimum 20 °C). Phylogenetic analysis based on 16S rRNA and gyrB gene sequences revealed that strain ST-6T belonged to a distinct lineage in the genus Shewanella. Strain ST-6T was related most closely to Shewanella basaltis J83T, S. gaetbuli TF-27T, S. arctica IT12T, S. vesiculosa M7T and S. aestuarii SC18T, showing 96-97 % and 85-70 % 16S rRNA and gyrB gene sequences similarities, respectively. DNA-DNA relatedness values between strain ST-6T and the type strains of two species of the genus Shewanella were <22.6 %. The major cellular fatty acids (>5 %) were summed feature 3 (comprising C16:1ω7c and/ or iso-C15:0 2-OH), C16:0, iso-C13:0 and C17:1ω8c. The DNA G+C content of strain ST-6Twas 42.4 mol%, and the predominant isoprenoid quinones were menaquinone MK-7 and ubiquinones Q-7 and Q-8. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain ST-6T is considered to represent a novel species of the genus Shewanella, for which the name Shewanella algicola sp. nov. is proposed. The type strain is ST-6T (= KCTC 23253T = JCM 31091T). PMID:26962005

  1. Bioconcentration of tetrachlorobenzene in marine algae

    NASA Astrophysics Data System (ADS)

    Wang, Xiu-Lin; Ma, Yan-Jun; Cheng, Gang; Yu, Wei-Jun; Zhang, Li-Jun

    1997-09-01

    Bioconcentration of tetrachlorobenzene (TeCB) in Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp., Platymonas subcordiformis, and Phaeodactylum tricornutum; and toxicity of TeCB to the marine algae were tested. Values of bioconcentration potential parameters, including uptake rate constant k 1, elimination rate constant k 2 and bioconcentration factor BCF, were obtained not only from the time course of TeCB uptake by the marine algae by using a bioconcentration model, but also from the acute toxicity test data for percent inhibition PI(%)˜exposure concentration of TeCB-time by using a combined bioconcentration and probability model. The results showed good relationship between k 1(TOXIC) and k 1(UPTAKE) and k 2(TOXIC), k 2(UPTAKE), and BCF D(IOXIC) and BCF D(UPTAKE). Especially, the values of BCF D(TOXIC) were well consistent with those of BCF D(UPTAKE).

  2. 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.

  3. PSI-driven cyclic electron flow allows intertidal macro-algae Ulva sp. (Chlorophyta) to survive in desiccated conditions.

    PubMed

    Gao, Shan; Shen, Songdong; Wang, Guangce; Niu, Jianfeng; Lin, Apeng; Pan, Guanghua

    2011-05-01

    Ulva sp. (Chlorophyta) is a representative species of the intertidal macro-algae responsible for the green tides that occurred along the shores of Qingdao in 2008 and had detrimental effects on the preparation for the 2008 Beijing Olympic Games sailing competition. In view of its significance, we have investigated the photosynthetic performance of the photosystems and the changes in photosynthetic electron transport that occur during desiccation and rehydration of Ulva sp. The PSII activity in Ulva sp. declined gradually during the course of desiccation, which was reflected by the decreased maximum quantum yield and effective quantum yield, whereas the PSI activity fluctuated significantly. In contrast, the electron transport rates of PSII approached zero at severe levels of desiccation, but the electron transport of PSI, which still operated, could be suppressed effectively by a specific inhibitor. Furthermore, the electron transport of PSI during rehydration of desiccated thalli was recovered faster than that of PSII. All these results implied that the linear electron flow was abolished in desiccated Ulva sp., whereas the cyclic PSI activity was significantly elevated, was still active at severe levels of desiccation and could be restored faster than PSII activity. Based on these results, we concluded the PSI-driven cyclic electron flow might provide desiccation tolerance and additional flexibility for the cell physiology of Ulva sp. under desiccation conditions, which might be one of the most important factors that make Ulva sp. well suited to experience daily cycles of desiccation at low tide and rehydration at high tide. PMID:21471121

  4. Importance of algae as a potential source of biofuel.

    PubMed

    Singh, A K; Singh, M P

    2014-01-01

    Algae have a great potential source of biofuels and also have unique importance to reduce gaseous emissions, greenhouse gases, climatic changes, global warming receding of glaciers, rising sea levels and loss of biodiversity. The microalgae, like Scenedesmus obliquus, Neochloris oleabundans, Nannochloropsis sp., Chlorella emersonii, and Dunaliella tertiolecta have high oil content. Among the known algae, Scenedesmus obliquus is one of the most potential sources for biodiesel as it has adequate fatty acid (linolenic acid) and other polyunsaturated fatty acids. Bio—ethanol is already in the market of United States of America and Europe as an additive in gasoline. Bio—hydrogen is the cleanest biofuel and extensive efforts are going on to bring it to market at economical price. This review highlights recent development and progress in the field of algae as a potential source of biofuel. PMID:25535720

  5. Performance assessment of biofuel production in an algae-based remediation system.

    PubMed

    Wuang, Shy Chyi; Luo, Yanpei Darren; Wang, Simai; Chua, Pei Qiang Danny; Tee, Pok Siang

    2016-03-10

    The production of biofuel from microalgae has been an area of great interest as microalgae have higher productivities than land plants, and certain species have high lipid constituents which are the major feedstock for biodiesel production. One way to enhance the economic feasibility of algal-based biofuel is to couple it with waste remediation. This study investigated the technical feasibility of cultivating Chlorella sp. and Nannochloropsis sp. with fish water for biofuel production. The remediation potential of Chlorella sp. was found to be higher but the lipid yield is lower, when compared to Nannochloropsis sp. Lipid productivities were found to be similar for both types of algae at 1.1-1.3mgL(-1)h(-1). The fatty acid profiles of the obtained lipids were found suitable for biofuel production, and the calorific values were high at 30-32MJ/kg. The results provide insights into lipid production in Chlorella sp. and Nannochloropsis sp., when coupled with waste remediation. PMID:26808868

  6. The effects of barley straw (Hordeum vulgare) on the growth of freshwater algae.

    PubMed

    Ferrier, M D; Butler, B R; Terlizzi, D E; Lacouture, R V

    2005-11-01

    Bioassays were conducted to determine the efficacy of barley straw liquor in controlling algal growth of 12 freshwater species of algae representing three divisions. Barley straw liquor inhibited the growth of three nuisance algae common in freshwater: Synura petersenii, Dinobyron sp., and Microcystis aeruginosa. However, Selenastrum capricornutum, Spirogyra sp., Oscillatoria lutea var. contorta, and Navicula sp. had significantly increased growth in the presence of straw liquor. The growth of the remainder, Ulothrix fimbriata, Scenedesmus quadricauda, Chlorella vulgaris, Anabaena flos-aquae, and Synedra sp. showed no significant difference from controls. In a related field study, we treated four of six ponds with barley straw and monitored their chlorophyll a levels for one growing season. While phytoplankton populations in all ponds decreased in midsummer, the phytoplankton biomass in treated ponds did not differ significantly from that of control ponds, suggesting that the application of barley straw had no effect on algal growth in these systems. PMID:16051085

  7. Bioaccumulation of arsenic by freshwater algae and the application to the removal of inorganic arsenic from an aqueous phase. Part II. By Chlorella vulgaris isolated from arsenic-polluted environment

    SciTech Connect

    Maeda, S.; Nakashima, S.; Takeshita, T.; Higashi, S.

    1985-01-01

    Green algae, Chlorella vulgaris Beijerinck var. vulgaris, isolated from an arsenic-polluted environment, was examined for the effects of arsenic levels, arsenic valence, temperature illumination intensity, phosphate levels, metabolism inhibitors, heat treatment on the growth, and arsenic bioaccumulation. The following conclusions were reached from the experimental results: (a) The growth of the cell increased with an increase of arsenic(V) levels of the medium up to 1000 ppm, and the cell survived even at 10,000 ppm; (b) The arsenic bioaccumulation increased with an increase of the arsenic level. The maximum accumulation of arsenic was about 50,000 ..mu..g As/g dry cell; (c) The growth decreased with an increase of the arsenic(III) level and the cell was cytolyzed at levels higher than 40 ppm; (d) No arsenic(V) was bioaccumulated by a cell which had been pretreated with dinitrophenol (respiratory inhibitor) or with heat. Little effect of NaN/sub 3/ (photosynthesis inhibitor) on the bioaccumulation was observed. 8 references, 2 figures, 6 tables.

  8. 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.

  9. 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.

  10. Sorption properties of algae Spirogyra sp. and their use for determination of heavy metal ions concentrations in surface water.

    PubMed

    Rajfur, Małgorzata; Kłos, Andrzej; Wacławek, Maria

    2010-11-01

    Kinetics of heavy-metal ions sorption by alga Spirogyra sp. was evaluated experimentally in the laboratory, using both the static and the dynamic approach. The metal ions--Mn(2+), Cu(2+), Zn(2+) and Cd(2+)--were sorbed from aqueous solutions of their salts. The static experiments showed that the sorption equilibria were attained in 30 min, with 90-95% of metal ions sorbed in first 10 min of each process. The sorption equilibria were approximated with the Langmuir isotherm model. The algae sorbed each heavy metal ions proportionally to the amount of this metal ions in solution. The experiments confirmed that after 30 min of exposition to contaminated water, the concentration of heavy metal ions in the algae, which initially contained small amounts of these metal ions, increased proportionally to the concentration of metal ions in solution. The presented results can be used for elaboration of a method for classification of surface waters that complies with the legal regulations. PMID:20435526

  11. 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

  12. Genome-Scale Metabolic Model for the Green Alga Chlorella vulgaris UTEX 395 Accurately Predicts Phenotypes under Autotrophic, Heterotrophic, and Mixotrophic Growth Conditions.

    PubMed

    Zuñiga, Cristal; Li, Chien-Ting; Huelsman, Tyler; Levering, Jennifer; Zielinski, Daniel C; McConnell, Brian O; Long, Christopher P; Knoshaug, Eric P; Guarnieri, Michael T; Antoniewicz, Maciek R; Betenbaugh, Michael J; Zengler, Karsten

    2016-09-01

    The green microalga Chlorella vulgaris has been widely recognized as a promising candidate for biofuel production due to its ability to store high lipid content and its natural metabolic versatility. Compartmentalized genome-scale metabolic models constructed from genome sequences enable quantitative insight into the transport and metabolism of compounds within a target organism. These metabolic models have long been utilized to generate optimized design strategies for an improved production process. Here, we describe the reconstruction, validation, and application of a genome-scale metabolic model for C. vulgaris UTEX 395, iCZ843. The reconstruction represents the most comprehensive model for any eukaryotic photosynthetic organism to date, based on the genome size and number of genes in the reconstruction. The highly curated model accurately predicts phenotypes under photoautotrophic, heterotrophic, and mixotrophic conditions. The model was validated against experimental data and lays the foundation for model-driven strain design and medium alteration to improve yield. Calculated flux distributions under different trophic conditions show that a number of key pathways are affected by nitrogen starvation conditions, including central carbon metabolism and amino acid, nucleotide, and pigment biosynthetic pathways. Furthermore, model prediction of growth rates under various medium compositions and subsequent experimental validation showed an increased growth rate with the addition of tryptophan and methionine. PMID:27372244

  13. Interactions between marine facultative epiphyte Chlamydomonas sp. (Chlamydomonadales, Chlorophyta) and ceramiaceaen algae (Rhodophyta).

    PubMed

    Klochkova, Tatyana A; Cho, Ga Youn; Boo, Sung Min; Chung, Ki Wha; Kim, Song Ja; Kim, Gwang Hoon

    2008-07-01

    Previously unrecorded marine Chlamydomonas that grew epiphytic on ceramiaceaen algae was collected from the western coast of Korea and isolated into a unialgal culture. The isolate was subjected to 18S rDNA phylogenetic analysis as well as ultrastructure and life cycle studies. It had an affinity with the marine Chlamydomonas species and was less related to freshwater/terrestrial representatives of this genus. It had flagella shorter than the cell body two-layered cell wall with striated outer surface and abundant mucilaginous material beneath the innermost layer and no contractile vacuoles. This alga grew faster in mixed cultures with ceramiaceaen algae rather than in any tested unialgal culture condition; the cells looked healthier and zoosporangia and motile flagellated vegetative cells appeared more often. These results suggested that this Chlamydomonas might be a facultative epiphyte benefiting from its hosts. Several ceramiaceaen algae were tested as host plants. Meanwhile, cell deformation or collapse of the whole thallus was caused to Aglaothamnion byssoides, and preliminary study suggested that a substance released from Chlamydomonas caused the response. This is first report on harmful epiphytic interactions between Chlamydomonas species and red ceramiaceaen algae. PMID:19195375

  14. Optimization of culturing conditions for toxicity testing with the alga Oophila sp. (Chlorophyceae), an amphibian endosymbiont.

    PubMed

    Rodríguez-Gil, José Luis; Brain, Richard; Baxter, Leilan; Ruffell, Sarah; McConkey, Brendan; Solomon, Keith; Hanson, Mark

    2014-11-01

    Eggs of the yellow-spotted salamander (Ambystoma maculatum) have a symbiotic relationship with green algae. It has been suggested that contaminants that are preferentially toxic to algae, such as herbicides, may impair the symbiont and, hence, indirectly affect the development of the salamander embryo. To enable testing under near-standard conditions for first-tier toxicity screening, the authors isolated the alga from field-collected eggs and identified conditions providing exponential growth rates in the apparent asexual phase of the alga. This approach provided a uniform, single-species culture, facilitating assessment of common toxicity end points and comparison of sensitivity relative to other species. Sequencing of the 18s ribosomal DNA indicated that the isolated alga is closely related to the recently described Oophila amblystomatis but is more similar to other known Chlamydomonas species, suggesting possible biogeographical variability in the genetic identity of the algal symbiont. After a tiered approach to culturing method refinement, a modified Bristol's media with 1 mM NH4 (+) as nitrogen source was found to provide suitable conditions for toxicity testing at 18 °C and 200 µmol m(-2) s(-1) photosynthetically active radiation (PAR) on a 24-h light cycle. The validity of the approach was demonstrated with Zn(2+) as a reference toxicant. Overall, the present study shows that screening for direct effects of contaminants on the algal symbiont without the presence of the host salamander is possible under certain laboratory conditions. PMID:25113146

  15. Preliminary development and evaluation of an algae-based air regeneration system

    NASA Technical Reports Server (NTRS)

    Nienow, J. A.

    2000-01-01

    The potential of air regeneration system based on the growth of microalgae on the surface of porous ceramic tubes is evaluated. The algae have been maintained in the system for extended periods, up to 360 days. Preliminary measurements of the photosynthetic capacity have been made for Chlorella vulgaris (UTEX 259), Neospongiococcum punctatum (UTEX 786), Stichococcus sp., and Gloeocapsa sp. Under standard test conditions (photosynthetic photon flux approximately 66 micromoles m-2 s-1, initial CO2 concentration approximately 450 micromoles mol-1), mature tubes remove up to 0.2 micromoles of CO2 per tube per minute. The rate of removal increases with photon flux up to at least 225 micromoles m-2 s-1 (PPF); peak rates of 0.35 micromoles of CO2 per tube per minute have been achieved with Chlorella vulgaris. These rates correspond to between 120 and 210 micromoles of CO2 removed per square meter of projected area per minute.

  16. 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

  17. Optimization of liquid media and biosafety assessment for algae-lysing bacterium NP23.

    PubMed

    Liao, Chunli; Liu, Xiaobo; Shan, Linna

    2014-09-01

    To control algal bloom caused by nutrient pollution, a wild-type algae-lysing bacterium was isolated from the Baiguishan reservoir in Henan province of China and identified as Enterobacter sp. strain NP23. Algal culture medium was optimized by applying a Placket-Burman design to obtain a high cell concentration of NP23. Three minerals (i.e., 0.6% KNO3, 0.001% MnSO4·H2O, and 0.3% K2HPO4) were found to be independent factors critical for obtaining the highest cell concentration of 10(13) CFU/mL, which was 10(4) times that of the control. In the algae-lysing experiment, the strain exhibited a high lysis rate for the 4 algae test species, namely, Chlorella vulgari, Scenedesmus, Microcystis wesenbergii, and Chlorella pyrenoidosa. Acute toxicity and mutagenicity tests showed that the bacterium NP23 had no toxic and mutagenic effects on fish, even in large doses such as 10(7) or 10(9) CFU/mL. Thus, Enterobacter sp. strain NP23 has strong potential application in the microbial algae-lysing project. PMID:25188453

  18. Effects of Dried Algae Schizochytrium Sp., A Rich Source of Docosahexaenoic Acid, on Growth, Fatty Acid Composition, and Sensory Quality of Channel Catfish Ictalurus Punctatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory study was conducted to investigate the effect of supplementation of dried algae Schizochytrium sp., a rich source of 22:6 n-3, on growth, fatty acid composition, and sensory quality of channel catfish Ictalurus punctatus. Five isonitrogenous (28% crude protein) and isocaloric (2.78 kcal...

  19. Effectiveness and toxicity of a novel isolated actinomycete strain Streptomyces sp. JS01 on a harmful alga Phaeocystis globosa.

    PubMed

    Zhang, Huajun; Zhang, Su; Peng, Yun; Li, Yi; Cai, Guanjing; Chen, Zhangran; Zheng, Wei; Tian, Yun; Xu, Hong; Zheng, Tianling

    2015-06-01

    An aquatic actinomycete capable of eliminating the brown tide causing marine alga Phaeocystis globosa was isolated from the surface sea water and the isolate named JS01 was characterized as Streptomyces on the basis of its 16S rRNA gene sequence. The supernatant of JS01 could lyse algal cells, implying that JS01 produced a latent alga-lytic compound. Considering this algicidal activity and the response of the algal cells, Chlorophyll a fluorescence decreased significantly in P. globosa in response to the JS01 supernatant when analyzed with flow cytometry. The algal cells experienced cell shrinkage and plasmolysis before disintegration after 72 h of treatment. The released algicide(s) were heat-tolerant, except above 121 °C, and fluctuation in pH variations; even so, algicidal activity was also over 60 %. The maximum toxicity of JS01 was on the seventh day of culture, and the relative luminosity was 0.49 at that time when detected by luminous bacteria Vibrio fischeri. These results indicated that the Streptomyces sp. JS01 could function as a potential controller of Phaeocystis globosa blooms. PMID:25638354

  20. Impact of green algae on the measurement of Microcystis aeruginosa populations in lagoon-treated wastewater with an algae online analyser.

    PubMed

    Nguyen, Thang; Roddick, Felicity A; Fan, Linhua

    2015-01-01

    Tests on the algae online analyser (AOA) showed that there was a strong direct linear correlation between cell density and in vivo Chl-a concentration for M. aeruginosa over the range of interest for a biologically treated effluent at a wastewater treatment plant (25,000-65,000 cells mL(-1), equivalent to a biovolume of 2-6 mm3 L(-1)). However, the AOA can provide an overestimate or underestimate of M. aeruginosa populations when green algae are present in the effluent, depending on their species and relative numbers. The results from this study demonstrated that the green algae (e.g., Euglena gracilis, Chlorella sp.) in the field phytoplankton population should be considered during calibration. In summary, the AOA has potential for use as an alert system for the presence of M. aeruginosa, and thus potentially of cyanobacterial blooms, in wastewater stabilization ponds. PMID:25204421

  1. 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.

  2. Effects of lead on growth, photosynthetic characteristics and production of reactive oxygen species of two freshwater green algae.

    PubMed

    Dao, Ly H T; Beardall, John

    2016-03-01

    In the natural environment, heavy metal contamination can occur as long-term pollution of sites or as pulses of pollutants from wastewater disposal. In this study two freshwater green algae, Chlorella sp. FleB1 and Scenedesmus YaA6, were isolated from lead-polluted water samples and the effects of 24 h vs 4 and 8 d exposure of cultures to lead on growth, photosynthetic physiology and production of reactive oxygen species (ROS) of these algae were investigated. In Chlorella sp. FleB1, there was agreement between lead impacts on chlorophyll content, photosynthesis and growth in most case. However, in Scenedesmus acutus YaA6 growth was inhibited at lower lead concentrations (0.03-0.87 × 10(-9) M), under which ROS, measured by 2',7' dichlorodihydrofluorescein diacetate fluorescence, were 4.5 fold higher than in controls but photosynthesis was not affected, implying that ROS had played a role in the growth inhibition that did not involve direct effects on photosynthesis. Effects of short-term (5 h, 24 h) vs long-term (4 d and 8 d) exposure to lead were also compared between the two algae. The results contribute to our understanding of the mechanisms of lead toxicity to algae. PMID:26774308

  3. Preparation and Evaluation of the Chelating Nanocomposite Fabricated with Marine Algae Schizochytrium sp. Protein Hydrolysate and Calcium.

    PubMed

    Lin, Jiaping; Cai, Xixi; Tang, Mengru; Wang, Shaoyun

    2015-11-11

    Marine algae have been becoming a popular research topic because of their biological implication. The algae peptide-based metal-chelating complex was investigated in this study. Schizochytrium sp. protein hydrolysate (SPH) possessing high Ca-binding capacity was prepared through stepwise enzymatic hydrolysis to a degree of hydrolysis of 22.46%. The nanocomposites of SPH chelated with calcium ions were fabricated in aqueous solution at pH 6 and 30 °C for 20 min, with the ratio of SPH to calcium 3:1 (w/w). The size distribution showed that the nanocomposite had compact structure with a radius of 68.16 ± 0.50 nm. SPH was rich in acidic amino acids, accounting for 33.55%, which are liable to bind with calcium ions. The molecular mass distribution demonstrated that the molecular mass of SPH was principally concentrated at 180-2000 Da. UV scanning spectroscopy and Fourier transform infrared spectroscopy suggested that the primary sites of calcium-binding corresponded to the carboxyl groups, carbonyl groups, and amino groups of SPH. The results of fluorescent spectroscopy, size distribution, atomic force microscope, and (1)H nuclear magnetic resonance spectroscopy suggested that calcium ions chelated with SPH would cause intramolecular and intermolecular folding and aggregating. The SPH-calcium chelate exerted remarkable stability and absorbability under either acidic or basic conditions, which was in favor of calcium absorption in the gastrointestinal tracts of humans. The investigation suggests that SPH-calcium chelate has the potential prospect to be utilized as a nutraceutical supplement to improve bone health in the human body. PMID:26499390

  4. Distinctive Architecture of the Chloroplast Genome in the Chlorodendrophycean Green Algae Scherffelia dubia and Tetraselmis sp. CCMP 881.

    PubMed

    Turmel, Monique; de Cambiaire, Jean-Charles; Otis, Christian; Lemieux, Claude

    2016-01-01

    The Chlorodendrophyceae is a small class of green algae belonging to the core Chlorophyta, an assemblage that also comprises the Pedinophyceae, Trebouxiophyceae, Ulvophyceae and Chlorophyceae. Here we describe for the first time the chloroplast genomes of chlorodendrophycean algae (Scherffelia dubia, 137,161 bp; Tetraselmis sp. CCMP 881, 100,264 bp). Characterized by a very small single-copy (SSC) region devoid of any gene and an unusually large inverted repeat (IR), the quadripartite structures of the Scherffelia and Tetraselmis genomes are unique among all core chlorophytes examined thus far. The lack of genes in the SSC region is offset by the rich and atypical gene complement of the IR, which includes genes from the SSC and large single-copy regions of prasinophyte and streptophyte chloroplast genomes having retained an ancestral quadripartite structure. Remarkably, seven of the atypical IR-encoded genes have also been observed in the IRs of pedinophycean and trebouxiophycean chloroplast genomes, suggesting that they were already present in the IR of the common ancestor of all core chlorophytes. Considering that the relationships among the main lineages of the core Chlorophyta are still unresolved, we evaluated the impact of including the Chlorodendrophyceae in chloroplast phylogenomic analyses. The trees we inferred using data sets of 79 and 108 genes from 71 chlorophytes indicate that the Chlorodendrophyceae is a deep-diverging lineage of the core Chlorophyta, although the placement of this class relative to the Pedinophyceae remains ambiguous. Interestingly, some of our phylogenomic trees together with our comparative analysis of gene order data support the monophyly of the Trebouxiophyceae, thus offering further evidence that the previously observed affiliation between the Chlorellales and Pedinophyceae is the result of systematic errors in phylogenetic reconstruction. PMID:26849226

  5. Distinctive Architecture of the Chloroplast Genome in the Chlorodendrophycean Green Algae Scherffelia dubia and Tetraselmis sp. CCMP 881

    PubMed Central

    Turmel, Monique; de Cambiaire, Jean-Charles; Otis, Christian; Lemieux, Claude

    2016-01-01

    The Chlorodendrophyceae is a small class of green algae belonging to the core Chlorophyta, an assemblage that also comprises the Pedinophyceae, Trebouxiophyceae, Ulvophyceae and Chlorophyceae. Here we describe for the first time the chloroplast genomes of chlorodendrophycean algae (Scherffelia dubia, 137,161 bp; Tetraselmis sp. CCMP 881, 100,264 bp). Characterized by a very small single-copy (SSC) region devoid of any gene and an unusually large inverted repeat (IR), the quadripartite structures of the Scherffelia and Tetraselmis genomes are unique among all core chlorophytes examined thus far. The lack of genes in the SSC region is offset by the rich and atypical gene complement of the IR, which includes genes from the SSC and large single-copy regions of prasinophyte and streptophyte chloroplast genomes having retained an ancestral quadripartite structure. Remarkably, seven of the atypical IR-encoded genes have also been observed in the IRs of pedinophycean and trebouxiophycean chloroplast genomes, suggesting that they were already present in the IR of the common ancestor of all core chlorophytes. Considering that the relationships among the main lineages of the core Chlorophyta are still unresolved, we evaluated the impact of including the Chlorodendrophyceae in chloroplast phylogenomic analyses. The trees we inferred using data sets of 79 and 108 genes from 71 chlorophytes indicate that the Chlorodendrophyceae is a deep-diverging lineage of the core Chlorophyta, although the placement of this class relative to the Pedinophyceae remains ambiguous. Interestingly, some of our phylogenomic trees together with our comparative analysis of gene order data support the monophyly of the Trebouxiophyceae, thus offering further evidence that the previously observed affiliation between the Chlorellales and Pedinophyceae is the result of systematic errors in phylogenetic reconstruction. PMID:26849226

  6. Algae fuel clean electricity generation

    SciTech Connect

    O'Sullivan, D.

    1993-02-08

    The paper describes plans for a 600-kW pilot generating unit, fueled by diesel and Chlorella, a green alga commonly seen growing on the surface of ponds. The plant contains Biocoil units in which Chlorella are grown using the liquid effluents from sewage treatment plants and dissolved carbon dioxide from exhaust gases from the combustion unit. The algae are partially dried and fed into the combustor where diesel fuel is used to maintain ignition. Diesel fuel is also used for start-up and as a backup fuel for seasonal shifts that affect the algae growing conditions. Since the algae use the carbon dioxide emitted during the combustion process, the process will not contribute to global warming.

  7. Genome of the halotolerant green alga Picochlorum sp. reveals strategies for thriving under fluctuating environmental conditions.

    PubMed

    Foflonker, Fatima; Price, Dana C; Qiu, Huan; Palenik, Brian; Wang, Shuyi; Bhattacharya, Debashish

    2015-02-01

    An expected outcome of climate change is intensification of the global water cycle, which magnifies surface water fluxes, and consequently alters salinity patterns. It is therefore important to understand the adaptations and limits of microalgae to survive changing salinities. To this end, we sequenced the 13.5 Mbp genome of the halotolerant green alga Picochlorum SENEW3 (SE3) that was isolated from a brackish water pond subject to large seasonal salinity fluctuations. Picochlorum SE3 encodes 7367 genes, making it one of the smallest and most gene dense eukaryotic genomes known. Comparison with the pico-prasinophyte Ostreococcus tauri, a species with a limited range of salt tolerance, reveals the enrichment of transporters putatively involved in the salt stress response in Picochlorum SE3. Analysis of cultures and the protein complement highlight the metabolic flexibility of Picochlorum SE3 that encodes genes involved in urea metabolism, acetate assimilation and fermentation, acetoin production and glucose uptake, many of which form functional gene clusters. Twenty-four cases of horizontal gene transfer from bacterial sources were found in Picochlorum SE3 with these genes involved in stress adaptation including osmolyte production and growth promotion. Our results identify Picochlorum SE3 as a model for understanding microalgal adaptation to stressful, fluctuating environments. PMID:24965277

  8. 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...

  9. Mameliella phaeodactyli sp. nov., a member of the family Rhodobacteraceae isolated from the marine algae Phaeodactylum tricornutum.

    PubMed

    Chen, Zhangran; Zhang, Jingyan; Lei, Xueqian; Lai, Qiliang; Yang, Luxi; Zhang, Huajun; Li, Yi; Zheng, Wei; Tian, Yun; Yu, Zhiming; Xu, Hong; Zheng, Tianling

    2015-05-01

    A novel Gram-staining-negative, aerobic, rod-shaped, non-motile, yellow bacterium designated strain KD53(T), was isolated from a culture of the alga Phaeodactylum tricornutum from Xiamen, Fujian Province, China. 16S rRNA gene sequence comparison showed that strain KD53(T) was a member of the Roseobacter clade within the family Rhodobacteraceae , forming a distinct lineage with species of the genus Mameliella . The 16S rRNA gene sequence similarities between strain KD53(T) and other strains examined were all less than 97.0%. Strain KD53(T) was found to grow optimally at 28 °C, at pH 7.5-8.0 and in the presence of 3% (w/v) NaCl. The dominant fatty acids of strain KD53(T) were C18 : 1ω6c and/or C18 : 1ω7c, C18 : 0 and C16 : 0. The major polar lipids were phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol. The DNA G+C content was 65 mol% and the major respiratory quinone was ubiquinone 10 (Q-10). On the basis of phenotypic data and phylogenetic inference, strain KD53(T) represents a novel member of the genus Mameliella , then the name Mameliella phaeodactyli sp. nov. is proposed. The type strain is KD53(T) ( =MCCC 1K00273(T) =KCTC 42178(T)). PMID:25716952

  10. The anti-allergic activity of polyphenol extracted from five marine algae

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Lin, Hong; Li, Zhenxing; Mou, Quangui

    2015-08-01

    Natural polyphenol has been widely believed to be effective in allergy remission. Currently, most of the natural polyphenol products come from terrestrial sources such as tea, grape seeds among others, and few polyphenols have been developed from algae for their anti-allergic activity. The aim of the study was to screen some commercial seaweed for natural extracts with anti-allergic activity. Five algae including Laminaria japonica, Porphyra sp., Spirulina platensis, Chlorella pyrenoidosa and Scytosiphon sp. were extracted with ethanol, and the extracts were evaluated for total polyphenol contents and anti-allergic activity with the hyaluronidase inhibition assay. Results showed that the total polyphenol contents in the ethanol extracts ranged from 1.67% to 8.47%, while the highest was found in the extract from Scytosiphon sp. Hyaluronidase inhibition assay showed that the extracts from Scytosiphon sp. had the lowest IC50, 0.67 mg mL-1, while Chlorella pyrenoidosa extract had the highest IC50, 15.07 mg mL-1. The anti-allergic activity of Scytosiphon sp. extract was even higher than the typical anti-allergic drug Disodium Cromoglycate (DSCG) (IC50 = 1.13 mg mL-1), and was similar with natural polyphenol from Epigallocatechin gallate (EGCG) (IC50 = 0.56 mg mL-1). These results indicated that the ethanol extract of Scytosiphon sp. contains a high concentration of polyphenol with high anti-allergic activity. Potentially Scytosiphon sp. can be developed to a natural anti-allergic compound for allergy remission.

  11. 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 ...

  12. Detection of herbicides in water and their interactions with chlorella kessleri

    NASA Astrophysics Data System (ADS)

    de Vries, Thorsten; Duling, Viviane; Anders, Angelika

    1999-09-01

    For the first time the herbicides ethidimuron, amizol and methabenzthiazuron were detected in water by means of time resolved laser fluorescence spectroscopy. The suitability of the algae chlorella kessleri as a biological indicator was tested. By using time resolved LIF, the herbicides' absorption spectra and their effects on the fluorescence properties of the algae it was possible to distinguish between the three herbicides.

  13. Phaeodactylibacter xiamenensis gen. nov., sp. nov., a member of the family Saprospiraceae isolated from the marine alga Phaeodactylum tricornutum.

    PubMed

    Chen, Zhangran; Lei, Xueqian; Lai, Qiliang; Li, Yi; Zhang, Bangzhou; Zhang, Jingyan; Zhang, Huajun; Yang, Luxi; Zheng, Wei; Tian, Yun; Yu, Zhiming; Xu, Hong; Zheng, Tianling

    2014-10-01

    A novel Gram-staining-negative, aerobic, rod-shaped, non-motile, reddish-orange and chemoheterotrophic bacteria, designated strain KD52(T), was isolated from a culture of the alga Phaeodactylum tricornutum from Xiamen, Fujian Province, China. 16S rRNA gene sequence comparison showed that strain KD52(T) was a member of the family Saprospiraceae, forming a distinct lineage with 'Portibacter lacus' KCTC 23747. The 16S rRNA gene sequence similarity between strain KD52(T) and the type strains of species of the family Saprospiraceae ranged from 86% to 89%. Growth occurred at 20-37 °C (optimum, 28 °C), in the presence of 1-9% (w/v) NaCl (optimum, 2.5%) and at pH 5-8.5 (optimum, pH 6.0). The dominant fatty acids (>10%) of strain KD52(T) were iso-C15:0 (33.1%), iso-C15:1 G (14.8%) and summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c, 13.8%). The major polar lipids were diphosphatidylglycerol, three unidentified phospholipids, four unknown lipids and one unidentified aminolipid. The DNA G+C content was 51 mol% and the major respiratory quinone was menaquinone-7 (MK-7). On the basis of phenotypic data and phylogenetic inference, strain KD52(T) represents a novel species of a new genus, for which the name Phaeodactylibacter xiamenensis gen. nov., sp. nov., is proposed. The type strain is KD52(T) ( = MCCC 1F01213(T) = KCTC 32575(T)). PMID:25052393

  14. [From algae to "functional foods"].

    PubMed

    Vadalà, M; Palmieri, B

    2015-01-01

    In the recent years, a growing interest for nutraceutical algae (tablets, capsules, drops) has been developed, due to their effective health benefits, as a potential alternative to the classic drugs. This review explores the use of cyanobacterium Spirulina, the microalgae Chlorella, Dunaliella, Haematococcus, and the macroalgae Klamath, Ascophyllum, Lithothamnion, Chondrus, Hundaria, Glacilaria, Laminaria, Asparagopsis, Eisenia, Sargassum as nutraceuticals and dietary supplements, in terms of production, nutritional components and evidence-based health benefits. Thus, our specific goals are: 1) Overview of the algae species currently used in nutraceuticals; 2) Description of their characteristics, action mechanisms, and possible side effects; 3) Perspective of specific algae clinical investigations development. PMID:26378764

  15. 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

  16. Toxic potential of iron oxide, CdS/Ag₂S composite, CdS and Ag₂S NPs on a fresh water alga Mougeotia sp.

    PubMed

    Jagadeesh, E; Khan, Behlol; Chandran, Preethy; Khan, S Sudheer

    2015-01-01

    Nanoparticles (NPs) are being used in many industries ranging from medical, textile, automobile, consumer products, etc. This may increase the probability of their (NPs) release into the environment and fresh water ecosystems. The present study focuses on testing the potential effect of iron oxide, nanocomposite of cadmium sulfide and silver sulfide, cadmium sulfide and silver sulfide nanoparticles (NPs) on a fresh water alga Mougeotia sp. as the model organism. The alga was treated with different concentrations of NPs (0.1-25 mg/L). The NPs exposure caused lipid peroxidation and ROS production, and suppressed the antioxidant defense system such as catalase, glutathione reductase, and superoxide dismutase. Adsorption of NPs on algal surface and membrane damage were confirmed through microscopic evaluation and increase in protein content in extracellular medium. The present investigation pointed out the ecological implications of NPs. The study warrants the need for regulatory agencies to monitor and regulate the use of NPs. PMID:25465759

  17. Transcriptome-wide analysis of DEAD-box RNA helicase gene family in an Antarctic psychrophilic alga Chlamydomonas sp. ICE-L.

    PubMed

    Liu, Chenlin; Huang, Xiaohang

    2015-09-01

    DEAD-box RNA helicase family proteins have been identified in almost all living organisms. Some of them play a crucial role in adaptation to environmental changes and stress response, especially in the low-temperature acclimation in different kinds of organisms. Compared with the full swing study in plants and bacteria, the characters and functions of DEAD-box family proteins had not been surveyed in algae. To identify genes critical for freezing acclimation in algae, we screened DEAD-box RNA helicase genes from the transcriptome sequences of a psychrophilic microalga Chlamydomonas sp. ICE-L which was isolated from Antarctic sea ice. Totally 39 DEAD-box RNA helicase genes had been identified. Most of the DEAD-box RNA helicase have 1:1 homologous relationships in Chlamydomonas reinhardtii and Chlamydomonas sp. ICE-L with several exceptions. The homologous proteins in ICE-L to the helicases critical for cold or freezing tolerance in Arabidopsis thaliana had been identified based on phylogenetic comparison studies. The response of these helicase genes is not always identical in the Chlamydomonas sp. ICE-L and Arabidopsis under the same low-temperature treatment. The expression of several DEAD-box RNA helicase genes including CiRH5, CiRH25, CiRH28, and CiRH55 were significantly up-regulated under freezing treatment of ICE-L and their function in freezing acclimation of ICE-L deserved further investigation. PMID:26174530

  18. Alterations in seawater pH and CO 2 affect calcification and photosynthesis in the tropical coralline alga, Hydrolithon sp. (Rhodophyta)

    NASA Astrophysics Data System (ADS)

    Semesi, I. Sware; Kangwe, Juma; Björk, Mats

    2009-09-01

    Calcification in the marine environment is the basis for the accretion of carbonate in structures such as coral reefs, algal ridges and carbonate sands. Among the organisms responsible for such calcification are the Corallinaceae (Rhodophyta), recognised as major contributors to the process world-wide. Hydrolithon sp. is a coralline alga that often forms rhodoliths in the Western Indian Ocean. In Zanzibar, it is commonly found in shallow lagoons, where it often grows within seagrass beds and/or surrounded by green algae such as Ulva sp. Since seagrasses in Zanzibar have recently been shown to raise the pH of the surrounding seawater during the day, and since calcification rates are sensitive to pH, which changes the saturation state of calcium carbonate, we measured the effects of pH on photosynthetic and calcification rates of this alga. It was found that pH had significant effects on both calcification and photosynthesis. While increased pH enhanced calcification rates both in the light and in the dark at pH >8.6, photosynthetic rates decreased. On the other hand, an increase in dissolved CO 2 concentration to ˜26 μmol kg -1 (by bubbling with air containing 0.9 mbar CO 2) caused a decrease in seawater pH which resulted in 20% less calcification after 5 days of exposure, while enhancing photosynthetic rates by 13%. The ecological implications of these findings is that photosynthetically driven changes in water chemistry by surrounding plants can affect calcification rates of coralline algae, as may future ocean acidification resulting from elevated atmospheric CO 2.

  19. Dimethyl carbonate-mediated lipid extraction and lipase-catalyzed in situ transesterification for simultaneous preparation of fatty acid methyl esters and glycerol carbonate from Chlorella sp. KR-1 biomass.

    PubMed

    Jo, Yoon Ju; Lee, Ok Kyung; Lee, Eun Yeol

    2014-04-01

    Fatty acid methyl esters (FAMEs) and glycerol carbonate were simultaneously prepared from Chlorella sp. KR-1 containing 40.9% (w/w) lipid using a reactive extraction method with dimethyl carbonate (DMC). DMC was used as lipid extraction agent, acyl acceptor for transesterification of the extracted triglycerides, substrate for glycerol carbonate synthesis from glycerol, and reaction medium for the solvent-free reaction system. For 1g of biomass, 367.31 mg of FAMEs and 16.73 mg of glycerol carbonate were obtained under the optimized conditions: DMC to biomass ratio of 10:1 (v/w), water content of 0.5% (v/v), and Novozyme 435 to biomass ratio of 20% (w/w) at 70°C for 24h. The amount of residual glycerol was only in the range of 1-2.5mg. Compared to conventional method, the cost of FAME production with the proposed technique could be reduced by combining lipid extraction with transesterification and omitting the extraction solvent recovery process. PMID:24583221

  20. Characterization and optimization of hydrogen production by a salt water blue-green alga Oscillatoria sp. Miami BG 7. II - Use of immobilization for enhancement of hydrogen production

    NASA Technical Reports Server (NTRS)

    Phlips, E. J.; Mitsui, A.

    1986-01-01

    The technique of cellular immobilization was applied to the process of hydrogen photoproduction of nonheterocystous, filamentous marine blue-green alga, Oscillatoria sp. Miami BG 7. Immobilization with agar significantly improved the rate and longevity of hydrogen production, compared to free cell suspensions. Rates of H2 production in excess of 13 microliters H2 mg dry/wt h were observed and hydrogen production was sustained for three weeks. Immobilization also provided some stabilization to environmental variability and was adaptable to outdoor light conditions. In general, immobilization provides significant advantages for the production and maintenance of hydrogen photoproduction for this strain.

  1. Responses of marine unicellular algae to brominated organic compounds in six growth media

    SciTech Connect

    Walsh, G.E.; Yoder, M.J.; McLaughlin, L.L.; Lores, E.M.

    1987-12-01

    Marine unicellular algae, Skeletonema costatum, Thalassiosira pseudonana, and Chlorella sp. were exposed to the industrial brominated compounds tetrabromobisphenol A, decabromobiphenyloxide (DBBO), hexabromocyclododecane (HBCD), pentabromomethylbenzene (PBMB), pentabromoethylbenzene (PBEB), and the herbicide bromoxynil (BROM), in six algal growth media. High concentrations of DBBO (1 mg liter-1), PBMB (1 mg liter-1), and PBEB (0.5 mg liter-1) reduced growth by less than 50%. EC50s of the other compounds varied with growth medium, with high EC50/low EC50 ratios between 1.3 and 9.9. Lowest EC50s, 9.3 to 12.0 micrograms liter-1, were obtained with S. costatum and HBCD. It is concluded that responses to toxicants in different media are the results of interactions among algae, growth medium, toxicant, and solvent carrier.

  2. Aurearenophyceae classis nova, a new class of Heterokontophyta based on a new marine unicellular alga Aurearena cruciata gen. et sp. nov. inhabiting sandy beaches.

    PubMed

    Kai, Atsushi; Yoshii, Yukie; Nakayama, Takeshi; Inouye, Isao

    2008-07-01

    A new heterokontophyte alga, Aurearena cruciata gen. et sp. nov., was isolated from sandy beaches in Japan. Isolates were characterized by light and electron microscopy, spectroscopy of pigment composition, and molecular phylogenetic analyses using 18S rDNA and rbcL. The alga usually possessed a cell wall but also retained two heterokont flagella beneath the cell wall. Each walled cell first produced only a single flagellate cell that subsequently divided into two flagellate cells. Electron-opaque vesicles, possibly associated with cell wall formation, were observed beneath the cell membrane. The chloroplast consisted of two compartments, each enclosed by a chloroplast envelope and the inner membrane of the chloroplast endoplasmic reticulum; these two compartments were surrounded by a common outer membrane of chloroplast endoplasmic reticulum. Molecular phylogenetic trees suggested that this alga was a new and independent member of the clade that included the Phaeophyceae and Xanthophyceae (PX clade). A new class, Aurearenophyceae classis nova was proposed for A. cruciata. PMID:18358776

  3. Antioxidant and antiproliferative activities of Spirulina and Chlorella water extracts.

    PubMed

    Wu, Li-chen; Ho, Ja-an Annie; Shieh, Ming-Chen; Lu, In-Wei

    2005-05-18

    Liver fibrosis is a chronic liver disease that will further develop to cirrhosis if severe damage continues to form. A potential treatment for liver fibrosis is to inhibit activated hepatic stellate cell (HSC) proliferation and, subsequently, to induce HSC apoptosis. It has been reported that antioxidants are able to inhibit the proliferation of HSCs. In this study, the aqueous extract of spirulina was chosen as the source of antioxidant to investigate the inhibitory effect on the proliferation of HSC. The growth inhibitory effects of aqueous spirulina and chlorella extract on human liver cancer cells, HepG2, were also studied and compared in pairs. Results indicated that the total phenol content of spirulina was almost five times greater than that of chlorella (6.86 +/- 0.58 vs 1.44 +/- 0.04 mg tannic acid equivalent/g of algae powder, respectively). The antioxidant activity of spirulina determined by the ABTS*+ method was higher than chlorella (EC50: 72.44 +/- 0.24 micromol of trolox equivalent/g of spirulina extract vs 56.09 +/- 1.99 micromol of trolox equivalent/g of chlorella extract). Results of DPPH* assay also showed a similar trend as the ABTS*+ assay (EC50: 19.39 +/- 0.65 micromol of ascorbic acid equivalent/g of spirulina extract vs 14.04 +/- 1.06 micromol of ascorbic acid equivalent/g of chlorella extract). The aqueous extracts of these two algae both showed antiproliferative effects on HSC and HepG2, but spirulina was a stronger inhibitor than chlorella. Annexin-V staining showed that aqueous extract of spirulina induced apoptosis of HSC after 12 h of treatment. In addition, the aqueous extract of spirulina triggered a cell cycle arrest of HSC at the G2/M phase. PMID:15884862

  4. Multi-gene phylogenetic analyses of New Zealand coralline algae: Corallinapetra Novaezelandiae gen. et sp. nov. and recognition of the Hapalidiales ord. nov.

    PubMed

    Nelson, Wendy A; Sutherland, Judith E; Farr, Tracy J; Hart, Darren R; Neill, Kate F; Kim, Hee Jeong; Yoon, Hwan Su

    2015-06-01

    Coralline red algae from the New Zealand region were investigated in a study focused on documenting regional diversity. We present a multi-gene analysis using sequence data obtained for four genes (nSSU, psaA, psbA, rbcL) from 68 samples. The study revealed cryptic diversity at both genus and species levels, confirming and providing further evidence of problems with current taxonomic concepts in the Corallinophycidae. In addition, a new genus Corallinapetra novaezelandiae gen. et sp. nov. is erected for material from northern New Zealand. Corallinapetra is excluded from all currently recognized families and orders within the Corallinophycidae and thus represents a previously unrecognized lineage within this subclass. We discuss rank in the Corallinophycidae and propose the order Hapalidiales. PMID:26986662

  5. Biomass and hydrogen photoproduction by a marine blue-green alga Oscillatoria sp. Miami BG 7 in natural seawater culture system

    SciTech Connect

    Ramachandran, S.

    1985-01-01

    A non-heterocystous marine blue-green alga Oscillatoria sp. Miami BG 7 showed high biomass yields and hydrogen production rates in a natural seawater based system. Variations in water quality such as salinity, pH, trace metal concentration and combined nitrogen level did not affect either the biomass or the hydrogen production. Recycling of the two steps involved in hydrogen production (i.e., aerobic growth phase and anaerobic hydrogen production phase) significantly increased (> 400%) the hydrogen yield. Immobilization of cells improved hydrogen production activity and its tolerance to adverse environmental conditions. Both the biomass and hydrogen production were not affected under uncontrolled outdoor environments. High biomass yield (250 mg dry wt/l/day or 40 g/m/sup 2//day), solar energy conversion efficiency (3.2%) and hydrogen production rate (1 ml H/sub 2//ml gel/day) were obtained in small scale outdoor systems.

  6. Crouania pumila sp. nov. (Callithamniaceae: Rhodophyta), a new species of marine red algae from the Seaflower International Biosphere Reserve, Caribbean Colombia.

    PubMed

    Gavio, Brigitte; Reyes-Gómez, Viviana P; Wynne, Michael J

    2013-09-01

    In the Colombian Caribbean, the marine macroalgal flora of the Seaflower International Biosphere Reserve has been little studied, despite its ecological importance. Historical records have reported only 201 macroalgae species within its area of almost 350,000 km2. However, recent surveys have shown a diversity of small algae previously overlooked. With the aim to determine the macroalgal diversity in the Reserve, we undertook field surveys in different ecosystems: coral reefs, seagrass beds, and rocky and sandy substrates, at different depths, from intertidal to 37 m. During these field surveys, we collected a small described species belonging to the genus Crouania (Callithamniaceae, Rhodophyta), Crouania pumila sp. nov. that is decribed in this paper. This new species was distinguished from other species of the genus by a distinctive suite of traits including its diminutive size (to only 3.5 mm in length), its decumbent, slightly calcified habit (epiphytic on other algae), its ramisympodial branching, the ecorticate main axes, and the elongate shape of the terminal cells of the cortical filaments. The observations were provided for both female (cystocarpic) and tetrasporangiate thalli; however, male thalli were not seen. Further studies have to be undertaken in this Reserve in order to carry out other macroalgal analysis and descriptions. PMID:24027904

  7. Acidophilic green alga Pseudochlorella sp. YKT1 accumulates high amount of lipid droplets under a nitrogen-depleted condition at a low-pH.

    PubMed

    Hirooka, Shunsuke; Higuchi, Sumio; Uzuka, Akihiro; Nozaki, Hisayoshi; Miyagishima, Shin-ya

    2014-01-01

    Microalgal storage lipids are considered to be a promising source for next-generation biofuel feedstock. However, microalgal biodiesel is not yet economically feasible due to the high cost of production. One of the reasons for this is that the use of a low-cost open pond system is currently limited because of the unavoidable contamination with undesirable organisms. Extremophiles have an advantage in culturing in an open pond system because they grow in extreme environments toxic to other organisms. In this study, we isolated the acidophilic green alga Pseudochlorella sp. YKT1 from sulfuric acid mine drainage in Nagano Prefecture, Japan. The vegetative cells of YKT1 display the morphological characteristics of Trebouxiophyceae and molecular phylogenetic analyses indicated it to be most closely related to Pseudochlorella pringsheimii. The optimal pH and temperature for the growth of YKT1 are pH 3.0-5.0 and a temperature 20-25°C, respectively. Further, YKT1 is able to grow at pH 2.0 and at 32°C, which corresponds to the usual water temperature in the outdoors in summer in many countries. YKT1 accumulates a large amount of storage lipids (∼30% of dry weigh) under a nitrogen-depleted condition at low-pH (pH 3.0). These results show that acidophilic green algae will be useful for industrial applications by acidic open culture systems. PMID:25221913

  8. Inhibitory effects of soluble algae products (SAP) released by Scenedesmus sp. LX1 on its growth and lipid production.

    PubMed

    Zhang, Tian-Yuan; Yu, Yin; Wu, Yin-Hu; Hu, Hong-Ying

    2013-10-01

    Soluble algal products (SAP) accumulated in culture medium via water reuse may affect the growth of microalga during the cultivation. Scenedesmus sp. LX1, a freshwater microalga, was used in this study to investigate the effect of SAP on growth and lipid production of microalga. Under the SAP concentrations of 6.4-25.8 mg L(-1), maximum algal density (K) and maximum growth rate (Rmax) of Scenedesmus sp. LX1 were decreased by 50-80% and 35-70% compared with the control group, respectively. The effect of SAP on lipid accumulation of Scenedesmus sp. LX1 was non-significant. According to hydrophilic-hydrophobic and acid-base properties, SAP was fractionized into six fractions. All of the fractions could inhibit the growth of Scenedesmus sp. LX1. Organic bases (HIB, HOB) and hydrophilic acids (HIA) showed the strongest inhibition. HIA could also decrease the lipid content of Scenedesmus sp. LX1 by 59.2%. As the inhibitory effect, SAP should be seriously treated before water reuse. PMID:23982061

  9. Use of biofuel by-product from the green algae Desmochloris sp. and diatom Nanofrustulum sp. meal in diets for nile tilapia Oreochromis niloticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Algal by-product meals from the Hawaiian biofuels industry were evaluated as protein ingredients in diets for juveniles of Nile tilapia (Oreochromis niloticus). Four experimental diets were formulated to contain 40% protein and were made with fish meal, soybean meal, whole diatom (Nanofrustulum sp.)...

  10. Pyrroline-5-Carboxylate Reductase in Chlorella autotrophica and Chlorella saccharophila in Relation to Osmoregulation 1

    PubMed Central

    Laliberté, Gilles; Hellebust, Johan A.

    1989-01-01

    Pyrroline-5-carboxylate (P5C) reductase (EC 1.5.1.2), which catalyzes the reduction of P5C to proline, was partially purified from two Chlorella species; Chlorella autotrophica, a euryhaline marine alga that responds to increases in salinity by accumulating proline and ions, and Chlorella saccharophila, which does not accumulate proline for osmoregulation. From the elution profile of this enzyme from an anion exchange column in Tris-HCl buffer (pH 7.6), containing sorbitol and glycine betaine, it was shown that P5C reductase from C. autotrophica was a neutral protein whereas the enzyme from C. saccharophila was negatively charged. The kinetic mechanisms of the reductase was characteristic of a ping-pong mechanism with double competitive substrate inhibition. Both enzymes showed high specificity for NADH as cofactor. The affinities of the reductases for their substrates did not change when the cells were grown at different salinities. In both algae, the apparent Km values of the reductase for P5C and NADH were 0.17 and 0.10 millimolar, respectively. A fourfold increase in maximal velocity of the reductase was observed when C. autotrophica was transferred from 50 to 150% artificial sea water. Even though the reductase was inhibited by NaCl, KCl, and proline, it still showed appreciable activity in the presence of these compounds at molar concentrations. A possible role for the regulation of proline synthesis at the step catalyzed by P5C reductase is discussed in relation to the specificity of P5C reductase for NADH and its responses to salt treatments. PMID:16667157

  11. Long-term experiment on physiological responses to synergetic effects of ocean acidification and photoperiod in the Antarctic sea ice algae Chlamydomonas sp. ICE-L.

    PubMed

    Xu, Dong; Wang, Yitao; Fan, Xiao; Wang, Dongsheng; Ye, Naihao; Zhang, Xiaowen; Mou, Shanli; Guan, Zheng; Zhuang, Zhimeng

    2014-07-15

    Studies on ocean acidification have mostly been based on short-term experiments of low latitude with few investigations of the long-term influence on sea ice communities. Here, the combined effects of ocean acidification and photoperiod on the physiological response of the Antarctic sea ice microalgae Chlamydomonas sp. ICE-L were examined. There was a general increase in growth, PSII photosynthetic parameters, and N and P uptake in continuous light, compared to those exposed to regular dark and light cycles. Elevated pCO2 showed no consistent effect on growth rate (p=0.8) and N uptake (p=0.38) during exponential phrase, depending on the photoperiod but had a positive effect on PSII photosynthetic capacity and P uptake. Continuous dark reduced growth, photosynthesis, and nutrient uptake. Moreover, intracellular lipid, mainly in the form of PUFA, was consumed at 80% and 63% in low and high pCO2 in darkness. However, long-term culture under high pCO2 gave a more significant inhibition of growth and Fv/Fm to high light stress. In summary, ocean acidification may have significant effects on Chlamydomonas sp. ICE-L survival in polar winter. The current study contributes to an understanding of how a sea ice algae-based community may respond to global climate change at high latitudes. PMID:24922067

  12. Metabolism of urea by Chlorella vulgaris.

    PubMed

    Hodson, R C; Thompson, J F

    1969-05-01

    Urea metabolism was studied with nitrogen-starved cells of Chlorella vulgaris Beijerinck var. viridis (Chodat), a green alga which apparently lacks urease. Incorporation of radioactivity from urea-(14)C into the alcohol-soluble fraction was virtually eliminated in cell suspensions flushed with 10% CO(2) in air. This same result was obtained when expected acceptors of urea carbon were replenished by adding ornithine and glucose with the urea. Several carbamyl compounds, which might be early products of urea metabolism and a source of the (14)CO(2), were not appreciably labeled. If cells were treated with cyanide at a concentration which inhibited ammonia uptake completely and urea uptake only slightly, more than half of the urea nitrogen taken up was found in the medium as ammonia. Cells under nitrogen gas in the dark were unable to take up urea or ammonia, but the normal rate of uptake was resumed in light. Since 3-(3,4-dichlorophenyl)-1,1-dimethylurea did not selectively inhibit this uptake, an active respiration supported by light-dependent oxygen evolution in these cells was ruled out. A tentative scheme for urea metabolism is proposed to consist of an initial energy-dependent splitting of urea into carbon dioxide and ammonia. This reaction in Chlorella is thought to differ from a typical urease-catalyzed reaction by the apparent requirement of a high energy compound, possibly adenosine triphosphate. PMID:5783973

  13. Symbiosis between hydra and chlorella: molecular phylogenetic analysis and experimental study provide insight into its origin and evolution.

    PubMed

    Kawaida, Hitomi; Ohba, Kohki; Koutake, Yuhki; Shimizu, Hiroshi; Tachida, Hidenori; Kobayakawa, Yoshitaka

    2013-03-01

    Although many physiological studies have been reported on the symbiosis between hydra and green algae, very little information from a molecular phylogenetic aspect of symbiosis is available. In order to understand the origin and evolution of symbiosis between the two organisms, we compared the phylogenetic relationships among symbiotic green algae with the phylogenetic relationships among host hydra strains. To do so, we reconstructed molecular phylogenetic trees of several strains of symbiotic chlorella harbored in the endodermal epithelial cells of viridissima group hydra strains and investigated their congruence with the molecular phylogenetic trees of the host hydra strains. To examine the species specificity between the host and the symbiont with respect to the genetic distance, we also tried to introduce chlorella strains into two aposymbiotic strains of viridissima group hydra in which symbiotic chlorella had been eliminated in advance. We discussed the origin and history of symbiosis between hydra and green algae based on the analysis. PMID:23219706

  14. [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. PMID:26021077

  15. The complete plastid genome sequence of the parasitic green alga Helicosporidium sp. is highly reduced and structured

    PubMed Central

    de Koning, Audrey P; Keeling, Patrick J

    2006-01-01

    Background Loss of photosynthesis has occurred independently in several plant and algal lineages, and represents a major metabolic shift with potential consequences for the content and structure of plastid genomes. To investigate such changes, we sequenced the complete plastid genome of the parasitic, non-photosynthetic green alga, Helicosporidium. Results The Helicosporidium plastid genome is among the smallest known (37.5 kb), and like other plastids from non-photosynthetic organisms it lacks all genes for proteins that function in photosynthesis. Its reduced size results from more than just loss of genes, however; it has little non-coding DNA, with only one intron and tiny intergenic spaces, and no inverted repeat (no duplicated genes at all). It encodes precisely the minimal complement of tRNAs needed to translate the universal genetic code, and has eliminated all redundant isoacceptors. The Helicosporidium plastid genome is also highly structured, with each half of the circular genome containing nearly all genes on one strand. Helicosporidium is known to be related to trebouxiophyte green algae, but the genome is structured and compacted in a manner more reminiscent of the non-photosynthetic plastids of apicomplexan parasites. Conclusion Helicosporidium contributes significantly to our understanding of the evolution of plastid DNA because it illustrates the highly ordered reduction that occurred following the loss of a major metabolic function. The convergence of plastid genome structure in Helicosporidium and the Apicomplexa raises the interesting possibility that there are common forces that shape plastid genomes, subsequent to the loss of photosynthesis in an organism. PMID:16630350

  16. The importance of light and photoperiod in sexual reproduction and geographical distribution in the green snow alga, Chloromonas sp.-D (Chlorophyceae, Volvocales)

    NASA Astrophysics Data System (ADS)

    Hoham, Ronald W.; Marcarelli, Amy M.; Rogers, Haldre S.; Ragan, Michael D.; Petre, Benjamin M.; Ungerer, Michael D.; Barnes, Joseph M.; Francis, David O.

    2000-12-01

    The effects of premating light regimes on sexual reproduction and the production of spherical cells in Chloromonas sp.-D, a unicellular green snow alga, were studied using cross-mating strains 582C and 582D isolated from snowpacks associated with mixed hardwood- softwood forests in Whetstone Gulf State Park, Tughill Plateau, NY. Two pre-acclimation regimes were used, Vita-Lite as controls (530- 700 nm peak) and blue light as experimentals (430- 460 nm peak) prior to the mating experiments. In blue light, an increase in the number of matings and spherical cells (spheres) produced in the life cycle was observed as the photoperiod increased. This implies that longer photoperiods of blue light are more optimal for sexual reproduction in Chloromonas sp.-D than shorter ones. Under Vita-Lite, there was a significant increase in the number of matings and spheres with the extended 20 : 4 photoperiod compared with the shorter 14 : 10 photoperiod. Under blue light, significantly more matings and spheres occurred than under Vita-Lite using the same irradiance level of 95µmol photons m-2 s-1 (photosynthetically active radiation [PAR] of 400- 700 nm) for the 14 : 10 and 20 : 4 photoperiods. The results of these experiments suggest that Chloromonas sp.-D, known only from the Tughill Plateau, NY, is not reproducing optimally at this site where it grows and reproduces under an approximate 14 : 10 photoperiod in early April. However, in the upper 10 cm of snow in the Tughill Plateau, a blue light irradiance level of 95µmol photons m-2 s-1 occurs, which is optimal for this species. When these conditions are combined with a 14 : 10 photoperiod, the Tughill Plateau appears to be sub-optimal for mating and production of spherical cells. Since Chloromonas sp.-D does not appear to have a dependence on a dark cycle, this would allow it to expand its geographical distribution. It may reproduce more optimally under blue light (95µmol photons m-2 s-1) with an extended photoperiod (>20 : 4

  17. Enhancement of Biodiesel Production from Marine Alga, Scenedesmus sp. through In Situ Transesterification Process Associated with Acidic Catalyst

    PubMed Central

    Kim, Ga Vin; Choi, WoonYong; Kang, DoHyung; Lee, ShinYoung; Lee, HyeonYong

    2014-01-01

    The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70°C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp. PMID:24689039

  18. The production of sulfonated chitosan-sodium alginate found in brown algae (Sargassum sp.) composite membrane as proton exchange membrane fuel cell (PEMFC)

    NASA Astrophysics Data System (ADS)

    Wafiroh, Siti; Pudjiastuti, Pratiwi; Sari, Ilma Indana

    2016-03-01

    The majority of energy was used in this period is from fossil fuel, which getting decreased in the future. The objective of this research is production and characterization of sulfonated chitosan-sodium alginate found in brown algae (Sargassum sp.) composite membrane as Proton Exchange Membrane Fuel Cell (PEMFC) for alternative energy. PEMFC was produced with 4 variations (w/w) ratio between chitosan and sodium alginate, 8 : 0, 8 : 1, 8 : 2, 8 : 4 (w/w). The production of membrane was mixed sodium alginate solution into chitosan solution and sulfonated with H2SO4 0.72 N. The characterization of the PEM was uses Modulus Young analysis, water swelling, ion exchange capacity, FTIR, SEM, DTA, methanol permeability and proton conductivity. The result of the research, showed that the optimum membrane was with ratio 8 : 2 (w/w) that the Modulus Young 8564 kN/m2, water swelling 31.86%, ion exchange capacity 1.020 meq/g, proton conductivity 8,8 × 10-6 S/cm, methanol permeability 1.90 × 10-8 g/cm2s and glass transition temperature (Tg) 100.9 °C, crystalline temperature (Tc) 227.6 °C, and the melting temperature (Tm) 267.9 °C.

  19. Symbiodinium thermophilum sp. nov., a thermotolerant symbiotic alga prevalent in corals of the world's hottest sea, the Persian/Arabian Gulf

    PubMed Central

    Hume, B. C. C.; D'Angelo, C.; Smith, E. G.; Stevens, J. R.; Burt, J.; Wiedenmann, J.

    2015-01-01

    Coral reefs are in rapid decline on a global scale due to human activities and a changing climate. Shallow water reefs depend on the obligatory symbiosis between the habitat forming coral host and its algal symbiont from the genus Symbiodinium (zooxanthellae). This association is highly sensitive to thermal perturbations and temperatures as little as 1°C above the average summer maxima can cause the breakdown of this symbiosis, termed coral bleaching. Predicting the capacity of corals to survive the expected increase in seawater temperatures depends strongly on our understanding of the thermal tolerance of the symbiotic algae. Here we use molecular phylogenetic analysis of four genetic markers to describe Symbiodinium thermophilum, sp. nov. from the Persian/Arabian Gulf, a thermally tolerant coral symbiont. Phylogenetic inference using the non-coding region of the chloroplast psbA gene resolves S. thermophilum as a monophyletic lineage with large genetic distances from any other ITS2 C3 type found outside the Gulf. Through the characterisation of Symbiodinium associations of 6 species (5 genera) of Gulf corals, we demonstrate that S. thermophilum is the prevalent symbiont all year round in the world's hottest sea, the southern Persian/Arabian Gulf. PMID:25720577

  20. Symbiodinium thermophilum sp. nov., a thermotolerant symbiotic alga prevalent in corals of the world's hottest sea, the Persian/Arabian Gulf.

    PubMed

    Hume, B C C; D'Angelo, C; Smith, E G; Stevens, J R; Burt, J; Wiedenmann, J

    2015-01-01

    Coral reefs are in rapid decline on a global scale due to human activities and a changing climate. Shallow water reefs depend on the obligatory symbiosis between the habitat forming coral host and its algal symbiont from the genus Symbiodinium (zooxanthellae). This association is highly sensitive to thermal perturbations and temperatures as little as 1°C above the average summer maxima can cause the breakdown of this symbiosis, termed coral bleaching. Predicting the capacity of corals to survive the expected increase in seawater temperatures depends strongly on our understanding of the thermal tolerance of the symbiotic algae. Here we use molecular phylogenetic analysis of four genetic markers to describe Symbiodinium thermophilum, sp. nov. from the Persian/Arabian Gulf, a thermally tolerant coral symbiont. Phylogenetic inference using the non-coding region of the chloroplast psbA gene resolves S. thermophilum as a monophyletic lineage with large genetic distances from any other ITS2 C3 type found outside the Gulf. Through the characterisation of Symbiodinium associations of 6 species (5 genera) of Gulf corals, we demonstrate that S. thermophilum is the prevalent symbiont all year round in the world's hottest sea, the southern Persian/Arabian Gulf. PMID:25720577

  1. Subunit Asa1 spans all the peripheral stalk of the mitochondrial ATP synthase of the chlorophycean alga Polytomella sp.

    PubMed

    Colina-Tenorio, Lilia; Miranda-Astudillo, Héctor; Cano-Estrada, Araceli; Vázquez-Acevedo, Miriam; Cardol, Pierre; Remacle, Claire; González-Halphen, Diego

    2016-04-01

    Mitochondrial F1FO-ATP synthase of chlorophycean algae is dimeric. It contains eight orthodox subunits (alpha, beta, gamma, delta, epsilon, OSCP, a and c) and nine atypical subunits (Asa1 to 9). These subunits build the peripheral stalk of the enzyme and stabilize its dimeric structure. The location of the 66.1kDa subunit Asa1 has been debated. On one hand, it was found in a transient subcomplex that contained membrane-bound subunits Asa1/Asa3/Asa5/Asa8/a (Atp6)/c (Atp9). On the other hand, Asa1 was proposed to form the bulky structure of the peripheral stalk that contacts the OSCP subunit in the F1 sector. Here, we overexpressed and purified the recombinant proteins Asa1 and OSCP and explored their interactions in vitro, using immunochemical techniques and affinity chromatography. Asa1 and OSCP interact strongly, and the carboxy-terminal half of OSCP seems to be instrumental for this association. In addition, the algal ATP synthase was partially dissociated at relatively high detergent concentrations, and an Asa1/Asa3/Asa5/Asa8/a/c10 subcomplex was identified. Furthermore, Far-Western analysis suggests an Asa1-Asa8 interaction. Based on these results, a model is proposed in which Asa1 spans the whole peripheral arm of the enzyme, from a region close to the matrix-exposed side of the mitochondrial inner membrane to the F1 region where OSCP is located. 3D models show elongated, helix-rich structures for chlorophycean Asa1 subunits. Asa1 subunit probably plays a scaffolding role in the peripheral stalk analogous to the one of subunit b in orthodox mitochondrial enzymes. PMID:26657474

  2. Description of Lecythium terrestris sp. nov. (Chlamydophryidae, Cercozoa), a Soil Dwelling Protist Feeding on Fungi and Algae.

    PubMed

    Dumack, Kenneth; Müller, Marina E H; Bonkowski, Michael

    2016-04-01

    Testate amoebae have been frequently studied by protistologists, but still little information is available on some groups like the Chlamydophryidae. These amoebae are difficult to culture and therefore quantitative information on their morphology, phylogeny and ecology is scarce. We isolated and cultured a small testate amoeba from an agricultural field at Müncheberg near Berlin, Germany. Morphological analyses revealed it to be a new species of the genus Lecythium. We describe Lecythium terrestris sp. nov. and present its morphology, mycophagous and algivorous feeding habits and its ability to form cell aggregates by fusion. Using small-subunit ribosomal RNA gene phylogeny, we could confirm the phylogenetic position of the genus Lecythium among the Cercozoa where it groups closely to Pseudodifflugiidae (Tectofilosida). PMID:26874465

  3. ALGAE-BACTERIA INTERACTION IN A LIGHT-DARK CYCLE (JOURNAL VERSION)

    EPA Science Inventory

    Nutrient and population dynamics accompanying algae-bacteria interaction were observed in unialgal, 18-liter batch cultures during a light-dark cycle. The green alga Chlorella vulgaris, and the nitrogen fixing blue-green Anabaena flos-aquae were inoculated with an aquatic communi...

  4. Effect of glutaphen on generation of active oxygen species, photosynthetic electron transport, and the functional activity of photosystem 2 in Chlorella cells

    NASA Astrophysics Data System (ADS)

    Samovich, T. V.; Pshibytko, N. L.; Averina, N. G.

    2006-11-01

    Treatment of chlorella green algae (Chlorella sp.) for 2 h in the dark with the photodynamic herbicide glutaphen (GTP), consisting of 0.3 mM 1,10-phenanthroline and 0.6 mM glutamic acid, followed by illumination leads to efficient generation of active oxygen species (AOS). After 15 min of illumination, AOS accumulation reaches 200% compared with the level in cells of the control culture, then it decreases down to 130% and 115% after 1 day and 3 days of illumination. During the first few days after treatment, we observe inhibition of synthesis of a specific precursor of chlorophyll (Chl): 5-aminolevulinic acid molecules, and then we observe stimulation of the synthesis. The effect of GTP on the photosynthetic activity of chlorella does not depend on the AOS level but rather remains uniform, in contrast to its effect on the Chl biosynthesis system. GTP does not change the efficiency of light harvesting and charge separation at the reaction centers of photosystem (PS) 2, but significantly lowers the functional efficiency of the electron transport chain: the photochemical quenching constants for Chl a fluorescence and the effective quantum yield of photochemical reactions in photosystem 2 decrease. The major mechanism of action for GTP is probably displacement of the secondary quinone acceptor QB from its binding site on the D1 protein by the 1,10-phenanthroline, consequent inhibition of electron efflux from Q{A/-} and increase in the fraction of QB-nonreducing centers of PS 2. The active oxygen species generated in the cells have a photodegradative effect on the Chl biosynthesis system, in particular on its initial steps, and do not involve already formed pigment-protein complexes of PS 2.

  5. [Study of the compatibility of certain higher plants and chlorella used as a bioregenerative human life support system].

    PubMed

    Shaĭdorov, Iu I; Shebalin, B N; Meleshko, G I

    1980-01-01

    The phototrophic component of a bioregenerative life support system should be of a multispecies structure. It should incorporate not only higher plants but also different algae. The paper discusses the studies concerning mutual effects of Chlorella and higher plants cultivated together in a closed atmosphere. It can be inferred from the studies that gaseous products of Chlorella did not exert a significant effect on the carbon dioxide consumption by wheat and radish plants or on their biomass increment. In turn, gaseous products of higher plants did not influence Chlorella growth. It can, therefore, be concluded that Chlorella and the above higher plants, when cultivated in a common atmosphere, do not inhibit each other and can be regarded as biologically compatible constituents of the photoautotrophic component of future bioregenerative life support systems. PMID:6104747

  6. 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.

  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. PMID:23973976

  8. Viruses of eukaryotic green algae. Progress report, August 1, 1982-July 1, 1984

    SciTech Connect

    Van Etten, J.L.

    1984-01-01

    The virus, PBCV-1, which infects the eukaryotic, green alga, Chlorella-NC64A has been characterized and we have begun to look at detailed events associated with its growth cycle. In addition, we have recently discovered other dsDNA viruses from natural sources which replicate in Chlorella NC64A. These viruses can be distinguished from PBCV-1 and from each other by plaque morphology, DNA restriction patterns, and by their resistance to certain restriction endonucleases.

  9. 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

  10. Production of Chlorella biomass enriched by selenium and its use in animal nutrition: a review.

    PubMed

    Doucha, Jirí; Lívanský, Karel; Kotrbácek, Václav; Zachleder, Vilém

    2009-07-01

    Feedstuffs are routinely supplemented with various selenium sources, where organic forms of Se are more bio-available and less toxic than the inorganic forms (selenites, selenates). When the algae are exposed to environmental Se in the form of selenite, they are able as other microorganisms to incorporate the element to different levels, depending on the algae species. Technology of heterotrophic fed-batch cultivation of the microalga Chlorella enriched by organically bound Se was developed, where the cultivation proceeds in fermentors on aerated and mixed nutrient solution with urea as a nitrogen and glucose as a carbon and energy source. High volumetric productivity and high cell concentrations (about 70-100 g Chlorella dry mass l(-1)) can be attained if nutrients and oxygen are adequately supplied. Addition of a small quantity of a new selenoprotein source-spray-dried Se-Chlorella biomass to the diet of farm animals had better effects on specific physiological and physical parameters of animals than selenite salt and was comparable with Se yeast added to the diet. This review introduces the importance of selenium for humans and animals, methods of Se determination, heterotrophic production of selenium-enriched Chlorella biomass in a fed-batch culture regime on organic carbon, and use of the biomass in animal nutrition. PMID:19533119

  11. Changes in arterial stiffness and nitric oxide production with Chlorella-derived multicomponent supplementation in middle-aged and older individuals

    PubMed Central

    Otsuki, Takeshi; Shimizu, Kazuhiro; Maeda, Seiji

    2015-01-01

    Chlorella is a unicellular green alga, which contains a variety of nutrients including amino acids, dietary fibers, n-3 unsaturated fatty acid, vitamins, and minerals. We previously demonstrated that Chlorella-derived multicomponent supplementation decreases arterial stiffness in young men. However, mechanisms underlying the reduction in arterial stiffness by Chlorella-derived supplementation and the effect in middle-aged and older individuals have remained unexplored. This study tested our hypothesis that Chlorella-derived supplementation improves arterial stiffness via an increase in nitric oxide (NO, a endothelium-derived relaxing factor) production in middle-aged and older individuals. Thirty-two subjects between 45 and 75 years of age assigned to placebo and Chlorella groups in a double-blinded manner and took respective tablets for 4 weeks. Before and after the supplementations, brachial-ankle pulse wave velocity (baPWV, an index of arterial stiffness) and plasma nitrite/nitrate (NOx, end product of NO) concentration were measured. There was no difference in baPWV between before and after the placebo intake, but baPWV decreased after the Chlorella supplementation. Changes in baPWV with the Chlorella supplementation were correlated with those in plasma NOx concentration. We concluded that Chlorella-derived multicomponent supplementation decreases arterial stiffness in middle-aged and older individuals. It may be associated with increase in NO production by vascular endothelium. PMID:26566309

  12. Changes in arterial stiffness and nitric oxide production with Chlorella-derived multicomponent supplementation in middle-aged and older individuals.

    PubMed

    Otsuki, Takeshi; Shimizu, Kazuhiro; Maeda, Seiji

    2015-11-01

    Chlorella is a unicellular green alga, which contains a variety of nutrients including amino acids, dietary fibers, n-3 unsaturated fatty acid, vitamins, and minerals. We previously demonstrated that Chlorella-derived multicomponent supplementation decreases arterial stiffness in young men. However, mechanisms underlying the reduction in arterial stiffness by Chlorella-derived supplementation and the effect in middle-aged and older individuals have remained unexplored. This study tested our hypothesis that Chlorella-derived supplementation improves arterial stiffness via an increase in nitric oxide (NO, a endothelium-derived relaxing factor) production in middle-aged and older individuals. Thirty-two subjects between 45 and 75 years of age assigned to placebo and Chlorella groups in a double-blinded manner and took respective tablets for 4 weeks. Before and after the supplementations, brachial-ankle pulse wave velocity (baPWV, an index of arterial stiffness) and plasma nitrite/nitrate (NOx, end product of NO) concentration were measured. There was no difference in baPWV between before and after the placebo intake, but baPWV decreased after the Chlorella supplementation. Changes in baPWV with the Chlorella supplementation were correlated with those in plasma NOx concentration. We concluded that Chlorella-derived multicomponent supplementation decreases arterial stiffness in middle-aged and older individuals. It may be associated with increase in NO production by vascular endothelium. PMID:26566309

  13. 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%.

  14. 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.

  15. [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. PMID:26164919

  16. A lipid-accumulating alga maintains growth in outdoor, alkaliphilic raceway pond with mixed microbial communities

    DOE PAGESBeta

    Bell, Tisza A.S.; Prithiviraj, Bharath; Wahlen, Brad D.; Fields, Matthew W.; Peyton, Brent M.

    2016-01-07

    Algal biofuels and valuable co-products are being produced in both open and closed cultivation systems. Growing algae in open pond systems may be a more economical alternative, but this approach allows environmental microorganisms to colonize the pond and potentially infect or outcompete the algal “crop.” In this study, we monitored the microbial community of an outdoor, open raceway pond inoculated with a high lipid-producing alkaliphilic alga, Chlorella vulgaris BA050. The strain C. vulgaris BA050 was previously isolated from Soap Lake, Washington, a system characterized by a high pH (~9.8). An outdoor raceway pond (200 L) was inoculated with C. vulgarismore » and monitored for 10 days and then the culture was transferred to a 2,000 L raceway pond and cultivated for an additional 6 days. Community DNA samples were collected over the 16-day period in conjunction with water chemistry analyses and cell counts. Universal primers for the SSU rRNA gene sequences for Eukarya, Bacteria, and Archaea were used for barcoded pyrosequence determination. The environmental parameters that most closely correlated with C. vulgaris abundance were pH and phosphate. Community analyses indicated that the pond system remained dominated by the Chlorella population (93% of eukaryotic sequences), but was also colonized by other microorganisms. Bacterial sequence diversity increased over time while archaeal sequence diversity declined over the same time period. Using SparCC co-occurrence network analysis, a positive correlation was observed between C. vulgaris and Pseudomonas sp. throughout the experiment, which may suggest a symbiotic relationship between the two organisms. The putative relationship coupled with high pH may have contributed to the success of C. vulgaris. As a result, the characterization of the microbial community dynamics of an alkaliphilic open pond system provides significant insight into open pond systems that could be used to control photoautotrophic biomass

  17. A Lipid-Accumulating Alga Maintains Growth in Outdoor, Alkaliphilic Raceway Pond with Mixed Microbial Communities

    PubMed Central

    Bell, Tisza A. S.; Prithiviraj, Bharath; Wahlen, Brad D.; Fields, Matthew W.; Peyton, Brent M.

    2016-01-01

    Algal biofuels and valuable co-products are being produced in both open and closed cultivation systems. Growing algae in open pond systems may be a more economical alternative, but this approach allows environmental microorganisms to colonize the pond and potentially infect or outcompete the algal “crop.” In this study, we monitored the microbial community of an outdoor, open raceway pond inoculated with a high lipid-producing alkaliphilic alga, Chlorella vulgaris BA050. The strain C. vulgaris BA050 was previously isolated from Soap Lake, Washington, a system characterized by a high pH (∼9.8). An outdoor raceway pond (200 L) was inoculated with C. vulgaris and monitored for 10 days and then the culture was transferred to a 2,000 L raceway pond and cultivated for an additional 6 days. Community DNA samples were collected over the 16-day period in conjunction with water chemistry analyses and cell counts. Universal primers for the SSU rRNA gene sequences for Eukarya, Bacteria, and Archaea were used for barcoded pyrosequence determination. The environmental parameters that most closely correlated with C. vulgaris abundance were pH and phosphate. Community analyses indicated that the pond system remained dominated by the Chlorella population (93% of eukaryotic sequences), but was also colonized by other microorganisms. Bacterial sequence diversity increased over time while archaeal sequence diversity declined over the same time period. Using SparCC co-occurrence network analysis, a positive correlation was observed between C. vulgaris and Pseudomonas sp. throughout the experiment, which may suggest a symbiotic relationship between the two organisms. The putative relationship coupled with high pH may have contributed to the success of C. vulgaris. The characterization of the microbial community dynamics of an alkaliphilic open pond system provides significant insight into open pond systems that could be used to control photoautotrophic biomass productivity in an

  18. A Lipid-Accumulating Alga Maintains Growth in Outdoor, Alkaliphilic Raceway Pond with Mixed Microbial Communities.

    PubMed

    Bell, Tisza A S; Prithiviraj, Bharath; Wahlen, Brad D; Fields, Matthew W; Peyton, Brent M

    2015-01-01

    Algal biofuels and valuable co-products are being produced in both open and closed cultivation systems. Growing algae in open pond systems may be a more economical alternative, but this approach allows environmental microorganisms to colonize the pond and potentially infect or outcompete the algal "crop." In this study, we monitored the microbial community of an outdoor, open raceway pond inoculated with a high lipid-producing alkaliphilic alga, Chlorella vulgaris BA050. The strain C. vulgaris BA050 was previously isolated from Soap Lake, Washington, a system characterized by a high pH (∼9.8). An outdoor raceway pond (200 L) was inoculated with C. vulgaris and monitored for 10 days and then the culture was transferred to a 2,000 L raceway pond and cultivated for an additional 6 days. Community DNA samples were collected over the 16-day period in conjunction with water chemistry analyses and cell counts. Universal primers for the SSU rRNA gene sequences for Eukarya, Bacteria, and Archaea were used for barcoded pyrosequence determination. The environmental parameters that most closely correlated with C. vulgaris abundance were pH and phosphate. Community analyses indicated that the pond system remained dominated by the Chlorella population (93% of eukaryotic sequences), but was also colonized by other microorganisms. Bacterial sequence diversity increased over time while archaeal sequence diversity declined over the same time period. Using SparCC co-occurrence network analysis, a positive correlation was observed between C. vulgaris and Pseudomonas sp. throughout the experiment, which may suggest a symbiotic relationship between the two organisms. The putative relationship coupled with high pH may have contributed to the success of C. vulgaris. The characterization of the microbial community dynamics of an alkaliphilic open pond system provides significant insight into open pond systems that could be used to control photoautotrophic biomass productivity in an open

  19. Overall Energy Considerations for Algae Species Comparison and Selection in Algae-to-Fuels Processes

    SciTech Connect

    Link, D.; Kail, B.; Curtis, W.; Tuerk,A.

    2011-01-01

    The controlled growth of microalgae as a feedstock for alternative transportation fuel continues to receive much attention. Microalgae have the characteristics of rapid growth rate, high oil (lipid) content, and ability to be grown in unconventional scenarios. Algae have also been touted as beneficial for CO{sub 2} reuse, as algae can be grown using CO{sub 2} emissions from fossil-based energy generation. Moreover, algae does not compete in the food chain, lessening the 'food versus fuel' debate. Most often, it is assumed that either rapid production rate or high oii content should be the primary factor in algae selection for algae-to-fuels production systems. However, many important characteristics of algae growth and lipid production must be considered for species selection, growth condition, and scale-up. Under light limited, high density, photoautotrophic conditions, the inherent growth rate of an organism does not affect biomass productivity, carbon fixation rate, and energy fixation rate. However, the oil productivity is organism dependent, due to physiological differences in how the organisms allocate captured photons for growth and oil production and due to the differing conditions under which organisms accumulate oils. Therefore, many different factors must be considered when assessing the overall energy efficiency of fuel production for a given algae species. Two species, Chlorella vulgaris and Botryococcus braunii, are popular choices when discussing algae-to-fuels systems. Chlorella is a very robust species, often outcompeting other species in mixed-culture systems, and produces a lipid that is composed primarily of free fatty acids and glycerides. Botryococcus is regarded as a slower growing species, and the lipid that it produces is characterized by high hydrocarbon content, primarily C28-C34 botryococcenes. The difference in growth rates is often considered to be an advantage oiChlorella. However, the total energy captured by each algal species in

  20. Catenovulum maritimus sp. nov., a novel agarolytic gammaproteobacterium isolated from the marine alga Porphyra yezoensis Ueda (AST58-103), and emended description of the genus Catenovulum.

    PubMed

    Li, Dong-Qi; Zhou, Yan-Xia; Liu, Tao; Chen, Guan-Jun; Du, Zong-Jun

    2015-08-01

    A novel agarolytic, Gram-stain negative, heterotrophic, facultatively anaerobic and pale-white pigmented bacterial strain, designated Q1(T), was isolated from the marine alga Porphyra yezoensis Ueda (AST58-103) collected from the coastal area of Weihai, China. The cells are motile by means of peritrichous flagella. The isolate requires NaCl for growth, while seawater is not necessary, and growth occurs optimally at about 30-33 °C, in 1-3 % (w/v) NaCl and at pH 7-7.5. Strain Q1(T) shows oxidase-positive and catalase-negative activities, and possesses the ability to hydrolyse starch and alginate, but not cellulose, gelatin, urea or Tween-80. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain Q1(T) is affiliated with the family Alteromonadaceae within the class Gammaproteobacteria. The isolate, strain Q1(T), is most closely related to Catenovulum agarivorans YM01(T) (94.85 %), with less than 91.2 % sequence similarity to other close relatives with validly published names. The draft genome sequence of strain Q1(T) consists of 62 contigs (>200 bp) of 4,548,270 bp. The genomes of Q1(T) and YM01(T) have an ANI value of 70.7 %, and the POCP value between the two genomes is 64.4 %. The genomic DNA G+C content of strain Q1(T) is 37.9 mol% as calculated from the draft genome sequence. The main isoprenoid quinone is ubiquinone-8. The predominant cellular fatty acids are summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH), C16:0 and C18:1 ω7c. The major polar lipids are phosphatidylethanolamine and phosphatidylglycerol. Based on data from a polyphasic chemotaxonomic, physiological and biochemical study, strain Q1(T) should be classified as a novel species of the genus Catenovulum, for which the name Catenovulum maritimus sp. nov. is proposed. The type strain is Q1(T) (=CICC 10836(T)=DSM 28813(T)). PMID:26036673

  1. 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.

  2. Effect of petroleum hydrocarbons on algae

    SciTech Connect

    Bhadauria, S. ); Sengar, R.M.S. ); Mittal, S.; Bhattacharjee, S. )

    1992-01-01

    Algal species (65) were isolated from oil refinery effluent. Twenty-five of these species were cultured in Benecke's medium in a growth chamber, along with controls. Retardation in algal growth, inhibition in algal photosynthesis, and discoloration was observed in petroleum enriched medium. Few forms, viz. Cyclotella sp., Cosmarium sp., and Merismopedia sp. could not survive. The lag phase lengthened by several days and slope of exponential phase was also depressed. Chlamydomonas sp., Scenedesmus sp., Ankistrodesmus sp., Nitzschia sp. and Navicula sp. were comparatively susceptible to petroleum. Depression in carbon fixation, cell numbers, and total dry algal mass was noticeable, showing toxicity to both diatoms and green algae.

  3. Algae-bacteria association inferred by 16S rDNA similarity in established microalgae cultures.

    PubMed

    Schwenk, Dagmar; Nohynek, Liisa; Rischer, Heiko

    2014-06-01

    Forty cultivable, visually distinct bacterial cultures were isolated from four Baltic microalgal cultures Chlorella pyrenoidosa, Scenedesmus obliquus, Isochrysis sp., and Nitzschia microcephala, which have been maintained for several years in the laboratory. Bacterial isolates were characterized with respect to morphology, antibiotic susceptibility, and 16S ribosomal DNA sequence. A total of 17 unique bacterial strains, almost all belonging to one of three families, Rhodobacteraceae, Rhizobiaceae, and Erythrobacteraceae, were subsequently isolated. The majority of isolated bacteria belong to Rhodobacteraceae. Literature review revealed that close relatives of the bacteria isolated in this study are not only often found in marine environments associated with algae, but also in lakes, sediments, and soil. Some of them had been shown to interact with organisms in their surroundings. A Basic Local Alignment Search Tool study indicated that especially bacteria isolated from the Isochrysis sp. culture were highly similar to microalgae-associated bacteria. Two of those isolates, I1 and I6, belong to the Cytophaga-Flavobacterium-Bacteroides phylum, members of which are known to occur in close communities with microalgae. An UniFrac analysis revealed that the bacterial community of Isochrysis sp. significantly differs from the other three communities. PMID:24799387

  4. 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

  5. [Study of the growth and development of Chlorella on "Kosmos-1887"].

    PubMed

    Sychev, V N; Levinskikh, M A; Livanskaia, O G

    1989-01-01

    The growth, development and population characteristics of Chlorella cells flown for 13 days in space were investigated during their postflight cultivation. The growth rate of flown algae did not differ from that of ground-based controls in terms of increases in the cell number and biomass. All basic parameters of the specimens (generation time, number of developing autospores, time ratio of developmental phases) were ontogentically normal. Exposure of the algae to space flight as a component of the algobacterial cenosis--fish autotrophic-heterotrophic system produced no significant effect of the population or individual specimens during their postflight cultivation. PMID:2593605

  6. Combined toxicity of pesticide mixtures on green algae and photobacteria.

    PubMed

    Liu, Shu-Shen; Wang, Cheng-Lin; Zhang, Jin; Zhu, Xiang-Wei; Li, Wei-Ying

    2013-09-01

    Different organisms have diverse responses to the same chemicals or mixtures. In this paper, we selected the green algae Chlorella pyrenoidosa (C. pyrenoidosa) and photobacteria Vibrio qinghaiensis sp.-Q67 (V. qinghaiensis) as target organisms and determined the toxicities of six pesticides, including three herbicides (simetryn, bromacil and hexazinone), two fungicides (dodine and metalaxyl) and one insecticide (propoxur), and their mixtures by using the microplate toxicity analysis. The toxicities of three herbicides to C. pyrenoidosa are much higher than those to V. qinghaiensis, and the toxicities of metalaxyl and propoxur to V. qinghaiensis are higher than those to C. pyrenoidosa, while the toxicity of dodine to C. pyrenoidosa is similar to those to V. qinghaiensis. Using the concentration addition as an additive reference model, the binary pesticide mixtures exhibited different toxicity interactions, i.e., displayed antagonism to C. pyrenoidosa but synergism to V. qinghaiensis. However, the toxicities of the multi-component mixtures of more than two components are additive and can be predicted by the concentration addition model. PMID:23816361

  7. Selection of microalgae and cyanobacteria strains for bicarbonate-based integrated carbon capture and algae production system.

    PubMed

    Chi, Zhanyou; Elloy, Farah; Xie, Yuxiao; Hu, Yucai; Chen, Shulin

    2014-01-01

    Using microalgae to capture CO2 from flue gas is an ideal way to reduce CO2 emission, but this is challenged by the high cost of carbon capture and transportation. To address this problem, a bicarbonate-based integrated carbon capture and algae production system (BICCAPS) has been proposed, in which bicarbonate is used for algae culture, and the regenerated carbonate from this process can be used to capture more CO2. High-concentration bicarbonate is obligate for the BICCAPS. Thus, different strains of microalgae and cyanobacteria were tested in this study for their capability to grow in high-concentration NaHCO3. The highest NaHCO3 concentrations they are tolerant to were determined as 0.30 M for Synechocystis sp. PCC6803, 0.60 M for Cyanothece sp., 0.10 M for Chlorella sorokiniana, 0.60 M for Dunaliella salina, and 0.30 M for Dunaliella viridis and Dunaliella primolecta. In further study, biomass production from culture of D. primolecta in an Erlenmeyer flask with either 0.30 M NaHCO3 or 2 % CO2 bubbling was compared, and no significant difference was detected. This indicates BICCAPS can reach the same biomass productivity as regular CO2 bubbling culture, and it is promising for future application. PMID:24092450

  8. Studies on the hormonal relationships of algae in pure culture : I. The effect of indole-3-acetic acid on the growth of blue-green and green algae.

    PubMed

    Ahmad, M R; Winter, A

    1968-09-01

    Indole-3-acetic acid (IAA) stimulated the growth (increase in dry weight) of the blue-green algae Anacystis nidulans, Chlorogloea fritschii, Phormidium foveolarum, Nostoc muscorum, Anabaena cylindrica, and Tolypothrix tenuis and the green algae Chlorella pyrenoidosa, Ankistrodesmus falcatus and Scenedesmus obliquus growing under as sterile conditions as possible. The optimum concentration varied from species to species; in the blue-green algae it ranged from 10(-5) to 10(-9) M and in the green algae it was 10(-3) M. These results are discussed in the light of present studies in this field. PMID:24522736

  9. The Study of Algae

    ERIC Educational Resources Information Center

    Rushforth, Samuel R.

    1977-01-01

    Included in this introduction to the study of algae are drawings of commonly encountered freshwater algae, a summary of the importance of algae, descriptions of the seven major groups of algae, and techniques for collection and study of algae. (CS)

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

    PubMed Central

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

    2016-01-01

    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

  11. 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

  12. Inhibition of mast cells by algae.

    PubMed

    Price, Joseph A; Sanny, Charles; Shevlin, Dennis

    2002-01-01

    There is a history of use of algae as foods and as food additives, or nutraceuticals. Although algae are a safe component of human foods and animal feeds, the effects of the algae other than as a source of protein are not clear. We examined the prevalence of an antiinflammatory activity in selected algae using, as an assay system, the inhibition of histamine release from mast cells. Methanolic extracts of eleven algae were examined for activity to inhibit the release of histamine from mast cells in vitro. This activity was found widely among the samples tested. The activities of these extracts were not uniformly stable in acid methanol. Selected extracts studied further did not separate with the use of size-exclusion filtration filters. LH-20 chromatography suggested at least two main elution areas of activity of the Chlorella extract. In summary, we saw wide phylogenetic dispersion of mast cell inhibition activity, suggesting that this antiinflammatory property is common in algae. This effect was apparently due to multiple activities within the algal extracts. PMID:12639395

  13. Gas Exchange of Algae

    PubMed Central

    Ammann, Elizabeth C. B.; Lynch, Victoria H.

    1965-01-01

    Continuously growing cultures of Chlorella pyrenoidosa Starr 252, operating at constant density and under constant environmental conditions, produced uniform photosynthetic quotient (PQ = CO2/O2) and O2 values during 6 months of observations. The PQ for the entire study was 0.90 ± 0.024. The PQ remained constant over a threefold light-intensity change and a threefold change in O2 production (0.90 ± 0.019). At low light intensities, when the rate of respiration approached the rate of photosynthesis, the PQ became extremely variable. Six lamps of widely different spectral-energy distribution produced no significant change in the PQ (0.90 ± 0.025). Oxygen production was directly related to the number of quanta available, irrespective of spectral-energy distribution. Such dependability in producing uniform PQ and O2 values warrants a consideration of algae to maintain a constant gas environment for submarine or spaceship use. Images Fig. 1 PMID:14339260

  14. Photorespiration in Air and High CO(2)-Grown Chlorella pyrenoidosa.

    PubMed

    Shelp, B J; Canvin, D T

    1981-12-01

    Oxygen inhibition of photosynthesis and CO(2) evolution during photorespiration were compared in high CO(2)-grown and air-grown Chlorella pyrenoidosa, using the artificial leaf technique at pH 5.0. High CO(2) cells, in contrast to air-grown cells, exhibited a marked inhibition of photosynthesis by O(2), which appeared to be competitive and similar in magnitude to that in higher C(3) plants. With increasing time after transfer to air, the photosynthetic rate in high CO(2) cells increased while the O(2) effect declined. Photorespiration, measured as the difference between (14)CO(2) and (12)CO(2) uptake, was much greater and sensitive to O(2) in high CO(2) cells. Some CO(2) evolution was also present in air-grown algae; however, it did not appear to be sensitive to O(2). True photosynthesis was not affected by O(2) in either case. The data indicate that the difference between high CO(2) and air-grown algae could be attributed to the magnitude of CO(2) evolution. This conclusion is discussed with reference to the oxygenase reaction and the control of photorespiration in algae. PMID:16662134

  15. Phycoremediation of textile wastewater by unicellular microalga Chlorella pyrenoidosa.

    PubMed

    Pathak, V V; Singh, D P; Kothari, R; Chopra, A K

    2014-01-01

    The potential application of microalga Chlorella pyrenoidosa was investigated for phycoremediation of textile wastewater. Two 15 days batch experiment containing autoclaved and unautoclaved textile wastewater were performed to measure the efficiency of alga to remediate the wastewater. Experiments were set at equivalent external conditions and pollutant load was measured on alternate of 5 days to determine the pollutant removal efficiency of alga. Alga was found to be more efficient in removal of pollutants load in autoclaved wastewater; agents of eutrophication such as nitrate and phosphate are reduced by 62% ±0.5 and 87% ±0.7 respectively while organic load in terms of BOD is reduced by 81% ±0.2 whereas, In unautoclaved wastewater in presence of algal-bacterial consortium, nitrate and phosphate were removed by 81% ±1 and 36% ±2.2 while BOD is reduced by 73% ±1.6 only. Another time dependent experiment of dye removal was also performed to measure the adsorption potential of selected dried algal biomass. An equal amount of dried algal biomass was introduced to various range of textile wastewater simulated with methylene blue (MB) dye. The maximum colour removal was observed afterduration of 30 minutes by dry algal biomass. PMID:25535710

  16. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats.

    PubMed

    Holzinger, Andreas; Allen, Michael C; Deheyn, Dimitri D

    2016-09-01

    Snow algae and green algae living in aeroterrestrial habitats are ideal objects to study adaptation to high light irradiation. Here, we used a detailed description of the spectral properties as a proxy for photo-acclimation/protection in snow algae (Chlamydomonas nivalis, Chlainomonas sp. and Chloromonas sp.) and charophyte green algae (Zygnema sp., Zygogonium ericetorum and Klebsormidium crenulatum). The hyperspectral microscopic mapping and imaging technique allowed us to acquire total absorption spectra of these microalgae in the waveband of 400-900nm. Particularly in Chlamydomonas nivalis and Chlainomonas sp., a high absorbance between 400-550nm was observed, due to naturally occurring secondary carotenoids; in Chloromonas sp. and in the charopyhte algae this high absorbance was missing, the latter being close relatives to land plants. To investigate if cellular water loss has an influence on the spectral properties, the cells were plasmolysed in sorbitol or desiccated at ambient air. While in snow algae, these treatments did hardly change the spectral properties, in the charopyhte algae the condensation of the cytoplasm and plastids increased the absorbance in the lower waveband of 400-500nm. These changes might be ecologically relevant and photoprotective, as aeroterrestrial algae are naturally exposed to occasional water limitation, leading to desiccation, which are conditions usually occurring together with higher irradiation. PMID:27442511

  17. Investigating the feasibility of growing algae for fuel in Southern nevada

    NASA Astrophysics Data System (ADS)

    Moazeni, Faegheh

    Microalgae capable of growing in waste are adequate to be mass-cultivated for biodiesel, avoiding fertilizers and clean water, two obstacles to sustainability of the feedstock production. This study replaces fertilizers and clean water with waste products. The investigated wastes include (1) the liquid fraction of sewage after solids and particles are removed, known as centrate, and (2) algal biomass residue, i.e. the algae remaining at the end of the lipids extraction process at biofuel plants. These wastes contain sufficient amount of nitrogen and phosphorus required for algal growth. This study proposes a system in which centrate would be used as an initial source of water and nutrients for microalgal growth. The generated biomass waste can be continuously recycled, serving as a fertilizer. If so desired, the centrate can be reverted back into the system from time to time as a nutrition supplement and as a make-up water source, particularly in open ponds that face evaporation. Of the six studied algae, i.e. Chlorella sorokiniana, Encyonema caespitosum, Nitzschia thermalis, Scenedesmus sp., Synechocystis sp., and Limnothrix sp., mostly isolated from the habitats influenced by municipal wastewater in and around the Las Vegas Valley, two green algae were eligible. In the laboratory, the green algae C. sorokiniana and Scenedesmus sp. grew in the media composed of centrate or algal residue faster than in the mineral medium BG11, optimized for algal growth. The enhanced productivity is mainly attributed to the photosynthesis known for mixotrophic process and the presence of organic carbon in the waste which serves as an extra source of energy. Tolerance for hard water and strong light and, in the case of C. sorokiniana , an unusually high optimum temperature between 32 and 35°C are also attributing factors to the enhanced productivity of algae. These studied species are particularly suited for cultivation in their native southwestern United States, particularly

  18. Comparison of the Photosynthetic Yield of Cyanobacteria and Green Algae: Different Methods Give Different Answers

    PubMed Central

    Schuurmans, R. Milou; van Alphen, Pascal; Schuurmans, J. Merijn; Matthijs, Hans C. P.; Hellingwerf, Klaas J.

    2015-01-01

    The societal importance of renewable carbon-based commodities and energy carriers has elicited a particular interest for high performance phototrophic microorganisms. Selection of optimal strains is often based on direct comparison under laboratory conditions of maximal growth rate or additional valued features such as lipid content. Instead of reporting growth rate in culture, estimation of photosynthetic efficiency (quantum yield of PSII) by pulse-amplitude modulated (PAM) fluorimetry is an often applied alternative method. Here we compared the quantum yield of PSII and the photonic yield on biomass for the green alga Chlorella sorokiniana 211-8K and the cyanobacterium Synechocystis sp. PCC 6803. Our data demonstrate that the PAM technique inherently underestimates the photosynthetic efficiency of cyanobacteria by rendering a high F0 and a low FM, specifically after the commonly practiced dark pre-incubation before a yield measurement. Yet when comparing the calculated biomass yield on light in continuous culture experiments, we obtained nearly equal values for both species. Using mutants of Synechocystis sp. PCC 6803, we analyzed the factors that compromise its PAM-based quantum yield measurements. We will discuss the role of dark respiratory activity, fluorescence emission from the phycobilisomes, and the Mehler-like reaction. Based on the above observations we recommend that PAM measurements in cyanobacteria are interpreted only qualitatively. PMID:26394153

  19. Comparison of the Photosynthetic Yield of Cyanobacteria and Green Algae: Different Methods Give Different Answers.

    PubMed

    Schuurmans, R Milou; van Alphen, Pascal; Schuurmans, J Merijn; Matthijs, Hans C P; Hellingwerf, Klaas J

    2015-01-01

    The societal importance of renewable carbon-based commodities and energy carriers has elicited a particular interest for high performance phototrophic microorganisms. Selection of optimal strains is often based on direct comparison under laboratory conditions of maximal growth rate or additional valued features such as lipid content. Instead of reporting growth rate in culture, estimation of photosynthetic efficiency (quantum yield of PSII) by pulse-amplitude modulated (PAM) fluorimetry is an often applied alternative method. Here we compared the quantum yield of PSII and the photonic yield on biomass for the green alga Chlorella sorokiniana 211-8K and the cyanobacterium Synechocystis sp. PCC 6803. Our data demonstrate that the PAM technique inherently underestimates the photosynthetic efficiency of cyanobacteria by rendering a high F0 and a low FM, specifically after the commonly practiced dark pre-incubation before a yield measurement. Yet when comparing the calculated biomass yield on light in continuous culture experiments, we obtained nearly equal values for both species. Using mutants of Synechocystis sp. PCC 6803, we analyzed the factors that compromise its PAM-based quantum yield measurements. We will discuss the role of dark respiratory activity, fluorescence emission from the phycobilisomes, and the Mehler-like reaction. Based on the above observations we recommend that PAM measurements in cyanobacteria are interpreted only qualitatively. PMID:26394153

  20. Separation, antitumor activities, and encapsulation of polypeptide from Chlorella pyrenoidosa.

    PubMed

    Wang, Xiaoqin; Zhang, Xuewu

    2013-01-01

    Chlorella pyrenoidosa is a unicellular green algae and has been a popular foodstuff worldwide. However, no reports on the antitumor peptides from such a microalgae are available in the literature. In this study, using low-temperature high-pressure extraction, enzymatic hydrolysis, ion exchange, and gel filtration chromatography, we separated a polypeptide that exhibited inhibitory activity on human liver cancer HepG2 cells, and named the polypeptide CPAP (C. pyrenoidosa antitumor polypeptide). Furthermore, the micro- and nanoencapsulation of CPAP were investigated by using two methods: complex coacervation and ionotropic gelation. The in vitro release tests revealed that CPAP was well preserved against gastric enzymatic degradation after micro/nanoencapsulation and the slowly controlled release in the intestine could be potentially achieved. These results suggest that CPAP may be a useful ingredient in food, nutraceutical, and pharmaceutical applications. PMID:23606619

  1. Effect of Interactions Among Algae on Nitrogen Fixation by Blue-Green Algae (Cyanobacteria) in Flooded Soils

    PubMed Central

    Wilson, John T.; Greene, Sarah; Alexander, Martin

    1979-01-01

    Nitrogen fixation (C2H2 reduction) by algae in flooded soil was limited by interactions within the algal community. Nitrogen fixation by either indigenous algae or Tolypothrix tenuis was reduced severalfold by a dense suspension of the green alga Nephrocytium sp. Similarly, interactions between the nitrogen-fixing alga (cyanobacterium) Aulosira 68 and natural densities of indigenous algae limited nitrogen-fixing activity in one of two soils examined. This was demonstrated by developing a variant of Aulosira 68 that was resistant to the herbicide simetryne at concentrations that prevented development of indigenous algae. More nitrogen was fixed by the resistant variant in flooded soil containing herbicide than was fixed in herbicide-free soil by either the indigenous algae or indigenous algae plus the parent strain of Aulosira. Interference from indigenous algae may hamper the development of nitrogen-fixing algae introduced into rice fields in attempts to increase biological nitrogen fixation. PMID:16345463

  2. Nutrient removal from horticultural wastewater by benthic filamentous algae Klebsormidium sp., Stigeoclonium spp. and their communities: From laboratory flask to outdoor Algal Turf Scrubber (ATS).

    PubMed

    Liu, Junzhuo; Danneels, Bram; Vanormelingen, Pieter; Vyverman, Wim

    2016-04-01

    Benthic filamentous algae have evident advantages in wastewater treatment over unicellular microalgae, including the ease in harvesting and resistance to predation. To assess the potentials of benthic filamentous algae in treating horticultural wastewater under natural conditions in Belgium, three strains and their mixture with naturally wastewater-borne microalgae were cultivated in 250 ml Erlenmeyer flasks in laboratory as well as in 1 m(2) scale outdoor Algal Turf Scrubber (ATS) with different flow rates. Stigeoclonium competed well with the natural wastewater-borne microalgae and contributed to most of the biomass production both in Erlenmeyer flasks and outdoor ATS at flow rates of 2-6 L min(-1) (water velocity 3-9 cm s(-1)), while Klebsormidium was not suitable for growing in horticultural wastewater under the tested conditions. Flow rate had great effects on biomass production and nitrogen removal, while phosphorus removal was less influenced by flow rate due to other mechanisms than assimilation by algae. PMID:26841229

  3. 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

  4. 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.

  5. Acidophilic algae isolated from mine-impacted environments and their roles in sustaining heterotrophic acidophiles

    PubMed Central

    Ňancucheo, Ivan; Barrie Johnson, D.

    2012-01-01

    Two acidophilic algae, identified as strains of Chlorella protothecoides var. acidicola and Euglena mutabilis, were isolated in pure culture from abandoned copper mines in Spain and Wales and grown in pH- and temperature-controlled bioreactors. The Chlorella isolate grew optimally at pH 2.5 and 30°C, with a corresponding culture doubling time of 9 h. The isolates displayed similar tolerance (10–50 mM) to four transition metals tested. Growth of the algae in liquid media was paralleled with increasing concentrations of dissolved organic carbon (DOC). Glycolic acid was identified as a significant component (12–14%) of total DOC. Protracted incubation resulted in concentrations of glycolic acid declining in both cases, and glycolic acid added to a culture of Chlorella incubated in the dark was taken up by the alga (~100% within 3 days). Two monosaccharides were identified in cell-free liquors of each algal isolate: fructose and glucose (Chlorella), and mannitol and glucose (Euglena). These were rapidly metabolized by acidophilic heterotrophic bacteria (Acidiphilium and Acidobacterium spp.) though only fructose was utilized by the more fastidious heterotroph “Acidocella aromatica.” The significance of algae in promoting the growth of iron- (and sulfate-) reducing heterotrophic acidophiles that are important in remediating mine-impacted waters (MIWs) is discussed. PMID:22973267

  6. The effect of algae species on the bioelectricity and biodiesel generation through open-air cathode microbial fuel cell with kitchen waste anaerobically digested effluent as substrate.

    PubMed

    Hou, Qingjie; Nie, Changliang; Pei, Haiyan; Hu, Wenrong; Jiang, Liqun; Yang, Zhigang

    2016-10-01

    Five strains algae (Golenkinia sp. SDEC-16, Chlorella vulgaris, Selenastrum capricornutum, Scenedesmus SDEC-8 and Scenedesmus SDEC-13) were screened as an effective way to promote recover electricity from MFC for kitchen waste anaerobically digested effluent (KWADE) treatment. The highest OCV, power density, biomass concentration and total lipid content were obtained with Golenkinia sp. SDEC-16 as the co-inoculum, which were 170mV, 6255mWm(-3), 325mgL(-1) and 38%, respectively. Characteristics of the organics in KWADE were analyzed, and the result showed that the hydrophilic and acidic fractions were more readily degraded, compared to the neutral fractions during the operation. Maximum COD and TN removal efficiency were 43.59% and 37.39% when inoculated with Golenkinia sp. SDEC-16, which were roughly 3.22 and 3.04 times higher than that of S. capricornutum. This study demonstrated that Golenkinia sp. SDEC-16 was a promising species for bioelectricity generation, lipid production and KWADE treatment. PMID:27441827

  7. 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.

  8. Phylogenetic relationships and taxonomic position of Chlorella-like isolates from low pH environments (pH < 3.0)

    PubMed Central

    Huss, Volker AR; Ciniglia, Claudia; Cennamo, Paola; Cozzolino, Salvatore; Pinto, Gabriele; Pollio, Antonino

    2002-01-01

    Background Little is known about phytoplankton communities inhabiting low pH environments such as volcanic and geothermal sites or acidic waters. Only specialised organisms are able to tolerate such extreme conditions. There is, thus, low species diversity. We have characterised the previously isolated acid tolerant Chlorella-like microalgae Viridiella fridericiana and Chlorella protothecoides var. acidicola by microscopical and biomolecular methods in order to assess their phylogenetic relationships. Results Both isolates belong to the trebouxiophycean lineage of chlorophytes. 18S and ITS1 sequence data clearly confirm that Viridiella fridericiana constitutes a new genus apart from the morphologically similar and likewise acid tolerant microalga Chlorella saccharophila. Chlorella protothecoides var. acidicola on the other hand is not a variety of Chlorella protothecoides but falls within a heterogeneous cluster consisting of Nannochloris, "Chlorella" spec. Yanaqocha, and Koliella, and is most closely related to algae which were also isolated from extreme environments. Conclusions The distribution of acid tolerant strains in the 18S rRNA tree shows that acquisition of acid tolerance was unlikely a monophyletic event in green microalgae. We propose that different strains have independently adapted to extreme environments. Some of them have spread worldwide and were able to colonise other extreme habitats. Considering the problems of successfully isolating acid tolerant strains, acidic soils could represent an unsuspected source of biological diversity with high potential for biotechnological utilisations. PMID:12194702

  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. PMID:26281556

  10. Photon up-conversion increases biomass yield in Chlorella vulgaris.

    PubMed

    Menon, Kavya R; Jose, Steffi; Suraishkumar, Gadi K

    2014-12-01

    Photon up-conversion, a process whereby lower energy radiations are converted to higher energy levels via the use of appropriate phosphor systems, was employed as a novel strategy for improving microalgal growth and lipid productivity. Photon up-conversion enables the utilization of regions of the solar spectrum, beyond the typical photosynthetically active radiation, that are usually wasted or are damaging to the algae. The effects of up-conversion of red light by two distinct sets of up-conversion phosphors were studied in the model microalgae Chlorella vulgaris. Up-conversion by set 1 phosphors led to a 2.85 fold increase in biomass concentration and a 3.2 fold increase in specific growth rate of the microalgae. While up-conversion by set 2 phosphors resulted in a 30% increase in biomass and 12% increase in specific intracellular neutral lipid, while the specific growth rates were comparable to that of the control. Furthermore, up-conversion resulted in higher levels of specific intracellular reactive oxygen species in C. vulgaris. Up-conversion of red light (654 nm) was shown to improve biomass yields in C. vulgaris. In principle, up-conversion can be used to increase the utilization range of the electromagnetic spectrum for improved cultivation of photosynthetic systems such as plants, algae, and microalgae. PMID:25155721

  11. 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

  12. Characterization of a single cell of Chlorella in a microfluidic channel using amperometric electrode arrays.

    PubMed

    Song, Young Seok; Bai, Seoung Jai

    2014-11-01

    Electrochemical characteristics of O2 and/or mediators secreted by a single cell of Chlorella fusea were analyzed by using amperometric measurements on microelectrodes embedded in a microfluidic device. A single cell was trapped in a microfluidic channel, which simplifies the mass transfer phenomenon, i.e., one-dimensional distribution of solutes in the channel. Such amperometric measurements allowed us to obtain more refined data in a localized space and to understand photosynthetic behavior of algae at the single cell level. In addition, the concentration of a photosynthetic mediator, p-benzoquinone, was numerically calculated by using the finite element method. PMID:24966046

  13. 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. PMID:25463782

  14. Characterization and bioavailability of vitamin B12-compounds from edible algae.

    PubMed

    Watanabe, Fumio; Takenaka, Shigeo; Kittaka-Katsura, Hiromi; Ebara, Shuhei; Miyamoto, Emi

    2002-10-01

    Substantial amounts of vitamin B12 were found in some edible algae (green and purple lavers) and algal health food (chlorella and spirulina tablets) using the Lactobacillus delbrueckii subsp. lactis ATCC7830 microbiological assay method. Corrinoid-compounds were purified and characterized from these algae to clarify the chemical properties and bioavailability of the algal vitamin B12. True vitamin B12 is the predominate cobamide of green and purple lavers and chlorella tablets. Feeding the purple laver to vitamin B12-deficient rats significantly improved the vitamin B12 status. The results suggest that algal vitamin B12 is a bioavailable source for mammals. Pseudovitamin B12 (an inactive corrinoid) predominated in the spirulina tablets, which are not suitable for use as a vitamin B12 source, especially for vegetarians. algal health food, bioavailability, cobalamin, edible algae, vitamin B12 PMID:12656203

  15. [Toxicity of Coptis chinensis Rhizome Extracts to Green Algae].

    PubMed

    Chen, Ya-nan; Yuan, Ling

    2015-05-01

    Coptis chinensis contains antiseptic alkaloids and thus its rhizomes and preparations are widely used for the treatment of.fish diseases. In order to realize the risk of water ecosystems produced by this medical herb and preparations used in aquaculture, the present experiment was carried out to study the toxicity of Coptis chinensis rhizome extract (CRE) to Scenedesmus oblique and Chlorella pyrenoidosa grown in culture solution with 0.00 (CK), 0.088 (Tl), 0.44 (T2) and 1.76 mg · L(-1) (T3) of CRE, respectively. The results show that low concentration of CRE (T1) inhibited the growth rate of the alga and high CRE (T2 and T3) ceased growth and reproductions. CRE also decreased the chlorophyll and proteins in alga cells, indicating the inhibition of photosynthesis and protein biosynthesis, which could be direct reasons for the low growth rate and death of green alga. The efflux of protons and substances from alga cells led to pH reduction and conductivity increment in culture solution with CRE. Furthermore, the activity of superoxide dismutase in alga increased at the beginning of CRE in T1 and T2 treatments but decreased as time prolonged which was in contrast to high CRE treatment. And the long exposure to low CRE treatment behaved otherwise. This suggests that the low concentration of CRE could induce the resistant reactions in alga at initial time but high CRE concentration or long exposure even at low CRE concentration could inhibit the enzyme synthesis. Similarly, malondialdehyde in alga increased as CRE concentrations increased in culture solutions, implying the damage and high permeability of cell membrane. In general, Chlorella pyrenoidosa was more sensitive to CRE. The abuse of rhizomes and preparations in aquaculture and intensive cultivation of Coptis chinensis plants in a large scale might produce ecological risks to primary productivity of water ecosystems. PMID:26314112

  16. 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

  17. 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

  18. 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

  19. ELLIPTOCHLORIS MARINA SP. NOV. (TREBOUXIOPHYCEAE, CHLOROPHYTA), SYMBIOTIC GREEN ALGA OF THE TEMPERATE PACIFIC SEA ANEMONES ANTHOPLEURA XANTHOGRAMMICA AND A. ELEGANTISSIMA (ANTHOZOA, CNIDARIA)(1).

    PubMed

    Letsch, Molly R; Muller-Parker, Gisèle; Friedl, Thomas; Lewis, Louise A

    2009-10-01

    Symbiotic green algae from two species of intertidal Pacific sea anemones, Anthopleura elegantissima and Anthopleura xanthogrammica, were collected from the northeastern Pacific coast of North America across the known range of the symbiont. Freshly isolated Anthopleura symbionts were used for both morphological and molecular analyses because Anthopleura symbiont cultures were not available. Light and transmission electron microscopy supported previous morphological studies, showing the symbionts consist of spherical unicells from 5 to 10 μm in diameter, with numerous vesicles, and a single bilobed chloroplast. Pyrenoids were not seen in LM, but a thylakoid-free area was observed in TEM, consistent with previous findings. Many algal cells extracted from fresh anemone tissue were observed in the process of division, producing two autospores within a maternal cell wall. The morphology of the green symbionts matches that of Elliptochloris Tscherm.-Woess. Molecular phylogenetic analyses of the nuclear SSU rDNA and the plastid encoded gene for the large subunit of RUBISCO (rbcL) support the monophyly of these green algal symbionts, regardless of host species and geographic origin. Phylogenetically, sequences of the Anthopleura symbionts are nested within the genus Elliptochloris and are distinct from sequences of all other Elliptochloris spp. examined. Given the ecological and phylogenetic distinctions among the green algal symbionts in Anthopleura spp. and the named species of Elliptochloris, we designate the green algal symbionts as a new species, Elliptochloris marina (Trebouxiophyceae, Chlorophyta). PMID:27032358

  20. Synchroma pusillum sp. nov. and other new algal isolates with chloroplast complexes confirm the Synchromophyceae (Ochrophyta) as a widely distributed group of amoeboid algae.

    PubMed

    Schmidt, Maria; Horn, Susanne; Flieger, Kerstin; Ehlers, Katrin; Wilhelm, Christian; Schnetter, Reinhard

    2012-07-01

    Seven new isolates of the heterokont algal class Synchromophyceae are described from coastal habitats of the Atlantic Ocean, including the Caribbean and Mediterranean Seas. All of the new isolates contain chloroplast complexes, a key feature of this group of algae. Morphology, pigments and DNA sequences support a monophyletic grouping of the Synchromophyceae to the exclusion of other Ochrophyta (primarily photosynthetic stramenopiles). Within the Synchromophyceae, two phylogenetic clades based on rbcL and 18S rDNA data were discovered, which differ in cell size and also the number of plastid complexes per cell. Two isolates form a clade with the type species Synchroma grande, while all other isolates form a separate clade, including the newly described species S. pusillum. Further species delineation of the isolates is difficult due to the highly similar morphology and life cycle strategy. Phylogenetic relationships with other genera of the Ochrophyta, such as Leukarachnion and Chlamydomyxa, are apparent and shed light on a heterogeneous branch of heterokont evolution. PMID:22578425

  1. Systematic and quantitative investigation of the mechanism of carbon nanotubes' toxicity toward algae.

    PubMed

    Long, Zhifeng; Ji, Jing; Yang, Kun; Lin, Daohui; Wu, Fengchang

    2012-08-01

    Concurrent with the increasing production and application of carbon nanotubes (CNTs) comes an increasing likelihood of CNTs presenting in the aquatic environment, and thereby potentially threatening aquatic organisms via toxic mechanisms that are, at present, poorly understood. This study systematically investigated the toxicity of three multiwalled CNT (MWCNT) samples toward a green alga (Chlorella sp.), focusing on examining and quantifying the contributions of five possible mechanisms to the algal growth inhibition. The results showed that the MWCNTs significantly inhibited the algal growth. The contribution of metal catalyst residues in the MWCNTs to the algal growth inhibition was negligible, as was the contribution from the MWCNTs' adsorption of nutrient elements. The algal toxicity of MWCNTs could mainly be explained by the combined effects of oxidative stress, agglomeration and physical interactions, and shading effects, with the quantitative contributions from these mechanisms depending on the MWCNT size and concentration. At MWCNT concentrations around 96 h IC(50), the oxidative stress accounted for approximately 50% of the algal growth inhibition, whereas the agglomeration and physical interactions, and the shading effects each took approximately 25% of the responsibility. PMID:22759191

  2. The oxygen evolving enhancer protein 1 (OEE) of photosystem II in green algae exhibits thioredoxin activity.

    PubMed

    Heide, Heinrich; Kalisz, Henryk M; Follmann, Hartmut

    2004-02-01

    A thioredoxin-like chloroplast protein of the fructosebisphosphatase-stimulating f-type, but with an unusually high molecular mass of 28 kDa has previously been identified and purified to homogeneity in a fractionation scheme for resolution of the acid- and heat-stable, regular-size (12kDa) thioredoxins of the unicellular green algae, Scenedesmus obliquus. An apparently analogous protein of 26 kDa was described in a cyanobacterium, Anabaena sp., but no such large thioredoxin species f exists in the thioredoxin profiles of higher plants. The structure of the 28 kDa protein, which had been envisaged to represent a precursor, or fusion product of the two more specialized, common chloroplast thioredoxins f and m has now been determined by amino acid sequencing. Although it exhibits virtually all the properties and enzyme-modulating activities of a thioredoxin proper this algal protein, surprisingly, does not belong to the thioredoxin family of small redox proteins but is identical with OEE (oxygen evolving enhancer) protein 1, an auxiliary component of the photosystem II manganese cluster. Extracts of Chlorella vulgaris and Chlamydomonas reinhardtii also contain heat-stable protein fractions of 23-26 kDa capable of specifically stimulating chloroplast fructosebisphosphatase in vitro. In contrast, OEE protein 1 from spinach is not able to modulate FbPase or NADP malate dehydrogenase from spinach chloroplasts. A dual function of the OEE protein in algal photosynthesis is envisaged. PMID:15022827

  3. [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

  4. 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. PMID:24331982

  5. Effect of selenate on viability and selenomethionine accumulation of Chlorella sorokiniana grown in batch culture.

    PubMed

    Gojkovic, Živan; Vílchez, Carlos; Torronteras, Rafael; Vigara, Javier; Gómez-Jacinto, Veronica; Janzer, Nora; Gómez-Ariza, José-Luis; Márová, Ivana; Garbayo, Ines

    2014-01-01

    The aim of this work was to study the effect of Se(+VI) on viability, cell morphology, and selenomethionine accumulation of the green alga Chlorella sorokiniana grown in batch cultures. Culture exposed to sublethal Se concentrations of 40 mg · L(-1) (212 μM) decreased growth rates for about 25% compared to control. A selenate EC50 value of 45 mg · L(-1) (238.2 μM) was determined. Results showed that chlorophyll and carotenoids contents were not affected by Se exposure, while oxygen evolution decreased by half. Ultrastructural studies revealed granular stroma, fingerprint-like appearance of thylakoids which did not compromise cell activity. Unlike control cultures, SDS PAGE electrophoresis of crude extracts from selenate-exposed cell cultures revealed appearance of a protein band identified as 53 kDa Rubisco large subunit of Chlorella sorokiniana, suggesting that selenate affects expression of the corresponding chloroplast gene as this subunit is encoded in the chloroplast DNA. Results revealed that the microalga was able to accumulate up to 140 mg · kg(-1) of SeMet in 120 h of cultivation. This paper shows that Chlorella sorokiniana biomass can be enriched in the high value aminoacid SeMet in batch cultures, while keeping photochemical viability and carbon dioxide fixation activity intact, if exposed to suitable sublethal concentrations of Se. PMID:24688385

  6. Effect of Selenate on Viability and Selenomethionine Accumulation of Chlorella sorokiniana Grown in Batch Culture

    PubMed Central

    Vílchez, Carlos; Torronteras, Rafael; Vigara, Javier; Gómez-Jacinto, Veronica; Janzer, Nora; Gómez-Ariza, José-Luis; Márová, Ivana

    2014-01-01

    The aim of this work was to study the effect of Se(+VI) on viability, cell morphology, and selenomethionine accumulation of the green alga Chlorella sorokiniana grown in batch cultures. Culture exposed to sublethal Se concentrations of 40 mg·L−1 (212 μM) decreased growth rates for about 25% compared to control. A selenate EC50 value of 45 mg·L−1 (238.2 μM) was determined. Results showed that chlorophyll and carotenoids contents were not affected by Se exposure, while oxygen evolution decreased by half. Ultrastructural studies revealed granular stroma, fingerprint-like appearance of thylakoids which did not compromise cell activity. Unlike control cultures, SDS PAGE electrophoresis of crude extracts from selenate-exposed cell cultures revealed appearance of a protein band identified as 53 kDa Rubisco large subunit of Chlorella sorokiniana, suggesting that selenate affects expression of the corresponding chloroplast gene as this subunit is encoded in the chloroplast DNA. Results revealed that the microalga was able to accumulate up to 140 mg·kg−1 of SeMet in 120 h of cultivation. This paper shows that Chlorella sorokiniana biomass can be enriched in the high value aminoacid SeMet in batch cultures, while keeping photochemical viability and carbon dioxide fixation activity intact, if exposed to suitable sublethal concentrations of Se. PMID:24688385

  7. Isolation and partial characterization of mutants with elevated lipid content in Chlorella sorokiniana and Scenedesmus obliquus.

    PubMed

    Vigeolas, Hélène; Duby, Francéline; Kaymak, Esra; Niessen, Guillaume; Motte, Patrick; Franck, Fabrice; Remacle, Claire

    2012-11-30

    This paper describes the isolation and partial biomass characterization of high triacylglycerol (TAG) mutants of Chlorella sorokiniana and Scenedesmus obliquus, two algal species considered as potential source of biodiesel. Following UV mutagenesis, 2000 Chlorella and 2800 Scenedesmus colonies were screened with a method based on Nile Red fluorescence. Several mutants with high Nile Red fluorescence were selected by this high-throughput method in both species. Growth and biomass parameters of the strongest mutants were analyzed in detail. All of the four Chlorella mutants showed no significant changes in growth rate, cell weight, cell size, protein and chlorophyll contents on a per cell basis. Whereas all contained elevated total lipid and TAG content per unit of dry weight, two of them were also affected for starch metabolism, suggesting a change in biomass/storage carbohydrate composition. Two Scenedesmus mutants showed a 1.5 and 2-fold increased cell weight and larger cells compared to the wild type, which led to a general increase of biomass including total lipid and TAG content on a per cell basis. Such mutants could subsequently be used as commercial oleaginous algae and serve as an alternative to conventional petrol. PMID:22480533

  8. 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. PMID:23613127

  9. 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). PMID:25543540

  10. 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

  11. Physiological and morphological responses of Lead or Cadmium exposed Chlorella sorokiniana 211-8K (Chlorophyceae).

    PubMed

    Carfagna, Simona; Lanza, Nicola; Salbitani, Giovanna; Basile, Adriana; Sorbo, Sergio; Vona, Vincenza

    2013-12-01

    The heavy metal pollution in soils and aquatic environments is a serious ecological problem. In the green-microalga Chlorella sorokiniana 211-8K (Chlorophyceae) exposed to ions of lead (Pb) and cadmium (Cd) we studied the metabolic responses to the toxicity of these two heavy metals. Our data indicate that both the pollutants alter the alga cell ultrastructure and its physiological characteristics (growth, photosynthesis, respiration, enzyme activities). The toxic effects of the two metals resulted time-dependent to the exposure. After 24 h of treatment with 250 μM Pb or Cd, photosynthesis was inhibited until to 77 and 86%, however respiration was strongly enhanced up to 300 and 350%, respectively. In the algal cells Pb or Cd exposure induced a reduction in the content of the total chlorophylls and a decrease of the soluble protein levels, significantly compromising the growth, particularly in cultures cadmium-treated. We report data on ultrastructural changes induced by the two heavy metals; they affected overall chloroplast ultrastructure of the alga. Most importantly, the O-acetyl-L-serine(thiol)lyase (OASTL) activity was appreciably increased after only 2 h of Cd exposure, indicating the existence of a link between the metal contamination and cysteine synthesis. Then, Chlorella sorokiniana cells seem to better tolerate high concentrations of Pb while appear to be more sensitive to Cd ions. These results provide some additional information that can lead to better understand consequences of heavy metal poisoning in microalgae. PMID:23641320

  12. Sequence and annotation of the 369-kb NY-2A and the 345-kb AR158 viruses that infect Chlorella NC64A.

    PubMed

    Fitzgerald, Lisa A; Graves, Michael V; Li, Xiao; Feldblyum, Tamara; Nierman, William C; Van Etten, James L

    2007-02-20

    Viruses NY-2A and AR158, members of the family Phycodnaviridae, genus Chlorovirus, infect the fresh water, unicellular, eukaryotic, chlorella-like green alga, Chlorella NC64A. The 368,683-bp genome of NY-2A and the 344,690-bp genome of AR158 are the two largest chlorella virus genomes sequenced to date; NY-2A contains 404 putative protein-encoding and 7 tRNA-encoding genes and AR158 contains 360 putative protein-encoding and 6 tRNA-encoding genes. The protein-encoding genes are almost evenly distributed on both strands, and intergenic space is minimal. Two of the NY-2A genes encode inteins, the large subunit of ribonucleotide reductase and a superfamily II helicase. These are the first inteins to be detected in the chlorella viruses. Approximately 40% of the viral gene products resemble entries in the public databases, including some that are unexpected for a virus. These include GDP-d-mannose dehydratase, fucose synthase, aspartate transcarbamylase, Ca(++) transporting ATPase and ubiquitin. Comparison of NY-2A and AR158 protein-encoding genes with the prototype chlorella virus PBCV-1 indicates that 85% of the genes are present in all three viruses. PMID:17027058

  13. Potential use of duckweed based anaerobic digester effluent as a feed source for heterotrophic growth of micro-algae

    NASA Astrophysics Data System (ADS)

    Ahmadi, L.; Dupont, R.

    2013-12-01

    Finding an alternative source of energy for the growing world's demand is a challenging task being considered by many scientists. Various types of renewable energy alternatives are being investigated by researchers around the world. The abundance of duckweed (i.e., Lemna and Wolfia sp.) in wetlands and wastewater lagoons, their rapid growth, and their capacity for nutrient, metal and other contaminant removal from wastewater suggests their potential as an inexpensive source of biomass for biofuel production. Another source of biomass for biofuel and energy production is micro-algae. The large-scale growth of micro-algae can potentially be achieved in a smaller footprint and at a higher rate and lower cost via heterotrophic growth compared to autotrophic growth for specific species that can grow under both conditions. Here we describe two types of research. First, two lab-scale, 5 L anaerobic digesters containing municipal raw wastewater that were set up, maintained and monitored over the course of 6 months using duckweed as the feed source. The pH, salinity, amount of gas production and gas composition were measured on a daily basis. The results from these measurements show that duckweed can be used as a good source of biofuel production in the form of methane gas. The second set of reactors consisted of two 1 L batch fed reactors containing algae (Chlorella vulgaris) grown in the lab environment heterotrophically. The pH and DO were monitored on a daily basis in order to investigate their effect on algae growth. Lipid analysis of the harvested algal biomass was done to investigate the efficiency of harvestable biofuel products. A nutrient solution containing glucose as an energy source was used as the initial feed solution, and the potential substitution of the glucose solution with the organic carbon residue from the duckweed digester effluent was investigated. Methane production, carbon stabilization, and gas composition results from the duckweed fed anaerobic

  14. Bioaccumulation of nickel by algae

    SciTech Connect

    Wang, H.K.; Wood, J.M.

    1984-02-01

    Six strains of algae and one Euglena sp. were tested for their ability to bioaccumulate nickel. Radioactive /sup 63/Ni was used together with a microplate technique to determine the conditions for nickel removal by axenic cultures of cyanobacteria, green algae, and one euglenoid. The cyanobacteria tested were found to be more sensitive to nickel toxicity than the green algae or the Euglena sp. The concentration factor (CF) for nickel was determined under a variety of conditions and found to be in the range from 0 to 3.0 x 10/sup 3/. The effect of environmental variables on nickel uptake was examined, and a striking pH effect for biaccumulation was observed, with most of the algal strains accumulating nickel optimally at approximately pH 8.0. Competition experiments for binding sites between nickel and other cations as well as with other complexing anions, showed that /sup 63/Ni uptake was affected only by cobalt and by humic acids.

  15. Harvesting fresh water and marine algae by magnetic separation: screening of separation parameters and high gradient magnetic filtration.

    PubMed

    Cerff, Martin; Morweiser, Michael; Dillschneider, Robert; Michel, Aymeé; Menzel, Katharina; Posten, Clemens

    2012-08-01

    In this study, the focus is on magnetic separation of fresh water algae Chlamydomonas reinhardtii and Chlorella vulgaris as well as marine algae Phaeodactylum tricornutum and Nannochloropsis salina by means of silica-coated magnetic particles. Due to their small size and low biomass concentrations, harvesting algae by conventional methods is often inefficient and cost-consuming. Magnetic separation is a powerful tool to capture algae by adsorption to submicron-sized magnetic particles. Hereby, separation efficiency depends on parameters such as particle concentration, pH and medium composition. Separation efficiencies of >95% were obtained for all algae while maximum particle loads of 30 and 77 g/g were measured for C. reinhardtii and P. tricornutum at pH 8 and 12, respectively. This study highlights the potential of silica-coated magnetic particles for the removal of fresh water and marine algae by high gradient magnetic filtration and provides critical discussion on future improvements. PMID:22705536

  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. PMID:25348363

  17. Cultivation of a microalga Chlorella vulgaris using recycled aqueous phase nutrients from hydrothermal carbonization process.

    PubMed

    Du, Zhenyi; Hu, Bing; Shi, Aimin; Ma, Xiaochen; Cheng, Yanling; Chen, Paul; Liu, Yuhuan; Lin, Xiangyang; Ruan, Roger

    2012-12-01

    This study investigated the feasibility of using recovered nutrients from hydrothermal carbonization (HTC) for cultivation of microalga Chlorella vulgaris. Different dilution multiples of 50, 100 and 200 were applied to the recycled process water from HTC and algal growth was compared among these media and a standard growth medium BG-11. Algae achieved a biomass concentration of 0.79 g/L on 50 × process water after 4 days. Algae removed total nitrogen, total phosphorus and chemical oxygen demand by 45.5-59.9%, 85.8-94.6% and 50.0-60.9%, respectively, on differently diluted process water. The fatty acid methyl ester yields for algae grown on the process water were 11.2% (50 ×), 11.2% (100 ×) and 9.7% (200 ×), which were significantly higher than 4.5% for BG-11. In addition, algae cultivated on process water had 18.9% higher carbon and 7.8% lower nitrogen contents than those on BG-11, indicating that they are very suitable as biofuel feedstocks. PMID:23116820

  18. [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

  19. Photorespiration and Oxygen Inhibition of Photosynthesis in Chlorella pyrenoidosa.

    PubMed

    Shelp, B J; Canvin, D T

    1980-05-01

    The inhibition of photosynthesis by O(2) in air-grown Chlorella pyrenoidosa was investigated using three experimental techniques (artificial leaf, aqueous method, and O(2) electrode) to measure carbon assimilation. CO(2) response curves were determined under different O(2), pH, and temperature conditions. Regardless of the experimental technique and condition, O(2) inhibition was not evident until a concentration of 50% was reached; V(max) values were reduced whereas K(m) (CO(2)) values were unaffected by the increasing O(2) concentration. The response of photosynthesis to O(2) was independent of CO(2) and HCO(3) (-) concentrations as well as temperature. Relative rates of photosynthesis showed a 4 to 5% stimulation in 2% O(2), a 12% inhibition in 50% O(2), and a 24% inhibition in 100% O(2). The inhibition by 50% O(2) was still reversible after 20 minutes exposure whereas 100% O(2) caused irreversible inhibition after only 4 minutes.The O(2) inhibition is discussed in terms of the oxygenase reaction and a Mehler reaction supporting pseudocyclic electron flow. The results are inconsistent with the proposals that photorespiration exists in these algae and that a CO(2)-concentrating mechanism suppresses the O(2) inhibition of photosynthesis. PMID:16661282

  20. 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

  1. Photosynthetic and cellular toxicity of cadmium in Chlorella vulgaris.

    PubMed

    Ou-Yang, Hui-Ling; Kong, Xiang-Zhen; Lavoie, Michel; He, Wei; Qin, Ning; He, Qi-Shuang; Yang, Bin; Wang, Rong; Xu, Fu-Liu

    2013-12-01

    The toxic effects of cadmium (Cd) on the green alga Chlorella vulgaris were investigated by following the response to Cd of various toxicity endpoints (cell growth, cell size, photochemical efficiency of PSII in the light or Φ(PSII), maximal photochemical efficiency or Fv/Fm, chlorophyll a fluorescence, esterase activity, and cell viability). These toxicity endpoints were studied in laboratory batch cultures of C. vulgaris over a long-term 96-h exposure to different Cd concentrations using flow cytometry and pulse amplitude modulated fluorometry. The sequence of sensitivity of these toxicity endpoints was: cell yield > Φ(PSII) ≈ esterase activity > Fv/Fm > chlorophyll a fluorescence ≈ cell viability. It is shown that cell apoptosis or cell death only accounted for a minor part of the reduction in cell yield even at very high algistatic free Cd²⁺ concentrations, and other mechanisms such as blocked cell divisions are major contributors to cell yield inhibition. Furthermore, cadmium may affect both the electron donors and acceptors of the electron transport chain at high free Cd²⁺ concentration. Finally, the resistance of cells to cell death was size-dependent; medium-sized cells had the highest toxicity threshold. The present study brings new insights into the toxicity mechanisms of Cd in C. vulgaris and provides a detailed comparison of the sensitivity of various Cd toxicity endpoints. PMID:23966280

  2. 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. PMID:23648333

  3. Paramecium bursaria Chlorella Virus 1 Encodes a Polyamine Acetyltransferase*

    PubMed Central

    Charlop-Powers, Zachary; Jakoncic, Jean; Gurnon, James R.; Van Etten, James L.; Zhou, Ming-Ming

    2012-01-01

    Paramecium bursaria chlorella virus 1 (PBCV-1), a large DNA virus that infects green algae, encodes a histone H3 lysine 27-specific methyltransferase that functions in global transcriptional silencing of the host. PBCV-1 has another gene a654l that encodes a protein with sequence similarity to the GCN5 family histone acetyltransferases. In this study, we report a 1.5 Å crystal structure of PBCV-1 A654L in a complex with coenzyme A. The structure reveals a unique feature of A654L that precludes its acetylation of histone peptide substrates. We demonstrate that A654L, hence named viral polyamine acetyltransferase (vPAT), acetylates polyamines such as putrescine, spermidine, cadaverine, and homospermidine present in both PBCV-1 and its host through a reaction dependent upon a conserved glutamate 27. Our study suggests that as the first virally encoded polyamine acetyltransferase, vPAT plays a possible key role in the regulation of polyamine catabolism in the host during viral replication. PMID:22277659

  4. Synchronous induction of detachment and reattachment of symbiotic Chlorella spp. from the cell cortex of the host Paramecium bursaria.

    PubMed

    Kodama, Yuuki; Fujishima, Masahiro

    2013-09-01

    Paramecium bursaria harbor several hundred symbiotic Chlorella spp. Each alga is enclosed in a perialgal vacuole membrane, which can attach to the host cell cortex. How the perialgal vacuole attaches beneath the host cell cortex remains unknown. High-speed centrifugation (> 1000×g) for 1min induces rapid detachment of the algae from the host cell cortex and concentrates the algae to the posterior half of the host cell. Simultaneously, most of the host acidosomes and lysosomes accumulate in the anterior half of the host cell. Both the detached algae and the dislocated acidic vesicles recover their original positions by host cyclosis within 10min after centrifugation. These recoveries were inhibited if the host cytoplasmic streaming was arrested by nocodazole. Endosymbiotic algae during the early reinfection process also show the capability of desorption after centrifugation. These results demonstrate that adhesion of the perialgal vacuole beneath the host cell cortex is repeatedly inducible, and that host cytoplasmic streaming facilitates recovery of the algal attachment. This study is the first report to illuminate the mechanism of the induction to desorb for symbiotic algae and acidic vesicles, and will contribute to the understanding of the mechanism of algal and organelle arrangements in Paramecium. PMID:23912150

  5. Energy Productivity of the High Velocity Algae Raceway Integrated Design (ARID-HV)

    SciTech Connect

    Attalah, Said; Waller, Peter M.; Khawam, George; Ryan, Randy D.; Huesemann, Michael H.

    2015-06-03

    The original Algae Raceway Integrated Design (ARID) raceway was an effective method to increase algae culture temperature in open raceways. However, the energy input was high and flow mixing was poor. Thus, the High Velocity Algae Raceway Integrated Design (ARID-HV) raceway was developed to reduce energy input requirements and improve flow mixing in a serpentine flow path. A prototype ARID-HV system was installed in Tucson, Arizona. Based on algae growth simulation and hydraulic analysis, an optimal ARID-HV raceway was designed, and the electrical energy input requirement (kWh ha-1 d-1) was calculated. An algae growth model was used to compare the productivity of ARIDHV and conventional raceways. The model uses a pond surface energy balance to calculate water temperature as a function of environmental parameters. Algae growth and biomass loss are calculated based on rate constants during day and night, respectively. A 10 year simulation of DOE strain 1412 (Chlorella sorokiniana) showed that the ARID-HV raceway had significantly higher production than a conventional raceway for all months of the year in Tucson, Arizona. It should be noted that this difference is species and climate specific and is not observed in other climates and with other algae species. The algae growth model results and electrical energy input evaluation were used to compare the energy productivity (algae production rate/energy input) of the ARID-HV and conventional raceways for Chlorella sorokiniana in Tucson, Arizona. The energy productivity of the ARID-HV raceway was significantly greater than the energy productivity of a conventional raceway for all months of the year.

  6. Viruses of eukaryotic green algae. Final technical report, June 1, 1989--February 1, 1992

    SciTech Connect

    Van Etten, J.L.

    1992-12-31

    We have isolated and partially characterized many large, polyhedral, DNA containing, plaque forming viruses which infect certain unicellular, eukaryotic, chlorella-like green algae. These viruses have several unique features, including the fact that they code for DNA site-specific endonucleases and DNA methyltransferases. The primary objectives of this study were to identify, clone, and characterize some of the virus-encoded DNA methyltransferases and DNA restriction endonucleases in order to understand their biological function.

  7. Algae culture for cattle feed and water purification. Final report

    SciTech Connect

    Varani, F.T.; Schellenbach, S.; Veatch, M.; Grover, P.; Benemann, J.

    1980-05-16

    The feasibility of algae growth on centrate from anaerobic digester effluent and the refeed of both effluent solids and the algae to feedlot cattle were investigated. The digester was operated with dirt feedlot manure. The study serves as a supplement for the work to design a utility sized digester for the City of Lamar to convert local feedlot manure into a fuel gas. The biogas produced would power the electrical generation plant already in service. Previous studies have established techniques of digester operation and the nutritional value for effluent solids as fed to cattle. The inclusion of a single-strain of algae, Chlorella pyrenidosa in the process was evaluated here for its capability (1) to be grown in both open and closed ponds of the discharge water from the solids separation part of the process, (2) to purify the discharge water, and (3) to act as a growth stimulant for cattle feed consumption and conversion when fed at a rate of 6 grams per head per day. Although it was found that the algae could be cultured and grown on the discharge water in the laboratory, the study was unable to show that algae could accomplish the other objectives successfully. However, the study yielded supplementary information useful to the overall process design of the utility plant. This was (1) measurement of undried digester solids fed to cattle in a silage finishing ration (without algae) at an economic value of $74.99 per dry ton based on nutritional qualities, (2) development of a centrate treatment system to decolorize and disinfect centrate to allow optimum algae growth, and (3) information on ionic and mass balances for the digestion system. It is the recommendation of this study that algae not be used in the process in the Lamar bioconversion plant.

  8. Heterotrophic Growth and Production of Xanthophylls by Chlorella pyrenoidosa

    PubMed Central

    Theriault, Robert J.

    1965-01-01

    The growth and level of xanthophylls of several representative species of green algae were investigated as a possible source of pigmentation for the egg yolk and broiler markets. Chlorella pyrenoidosa 7-11-05 was selected for fermentation studies because of its high level of xanthophylls and wide temperature range for growth. The heterotrophic metabolism was preferred because of the ease of adaptability to present fermentation equipment. When used as the sole carbon source, glucose was the only sugar, among many tested, that gave appreciable growth in illuminated shaken flasks. A dry cell weight of 90 g per liter and total xanthophylls of 450 mg per liter were obtained from 190 g per liter of glucose monohydrate in 168-hr illuminated shaken flasks. Higher levels of glucose decreased yields. In combination with glucose, monosaccharides, such as fructose and galactose, were readily assimilated. The 7-11-05 strain was adapted to galactose as the sole carbon source after six vegetative passages. Light of the proper intensity and duration stimulated total xanthophylls approximately 35%. The effect on dry cell weight and total xanthophylls of seven antibiotics added at various levels in shaken flasks was studied. Erythromycin was essentially stable throughout the fermentation and nontoxic up to 25 μg/ml, with only slight toxicity at higher levels. Both erythromycin and ristocetin were effective in controlling a high incidence of bacterial contamination in 30-liter fermentors. With the higher agitation and aeration rates possible in 30-liter fermentors, dry cell weights in excess of 100 g per liter and total xanthophylls of 467 to 512 mg per liter were readily obtained from 230 to 260 g per liter of glucose in 162-hr illuminated batch-type fermentations. Continuous-feed runs yielded a dry cell weight of 302 g per liter and total xanthophylls of 650 mg per liter from 520 g per liter of glucose. The type of Chlorella cell produced was an important consideration with

  9. Application of algae-biosensor for environmental monitoring.

    PubMed

    Umar, Lazuardi; Alexander, Frank A; Wiest, Joachim

    2015-08-01

    Environmental problems including water and air pollution, over fertilization, insufficient wastewater treatment and even ecological disaster are receiving greater attention in the technical and scientific area. In this paper, a method for water quality monitoring using living green algae (Chlorella Kessleri) with the help of the intelligent mobile lab (IMOLA) is presented. This measurement used two IMOLA systems for measurement and reference simultaneously to verify changes due to pollution inside the measurement system. The IMOLA includes light emitting diodes to stimulate photosynthesis of the living algae immobilized on a biochip containing a dissolved oxygen microsensor. A fluid system is used to transport algae culture medium in a stop and go mode; 600s ON, 300s OFF, while the oxygen concentration of the water probe is measured. When the pump stops, the increase in dissolved oxygen concentration due to photosynthesis is detected. In case of a pollutant being transported toward the algae, this can be detected by monitoring the photosynthetic activity. Monitoring pollution is shown by adding emulsion of 0,5mL of Indonesian crude palm oil and 10mL algae medium to the water probe in the biosensor. PMID:26737928

  10. Anticancer and antioxidant activities of the peptide fraction from algae protein waste.

    PubMed

    Sheih, I-Chuan; Fang, Tony J; Wu, Tung-Kung; Lin, Peng-Hsiang

    2010-01-27

    Algae protein waste is a byproduct during production of algae essence from Chlorella vulgaris. There is no known report on the anticancer peptides derived from the microalgae protein waste. In this paper, the peptide fraction isolated from pepsin hydrolysate of algae protein waste had strong dose-dependent antiproliferation and induced a post-G1 cell cycle arrest in AGS cells; however, no cytotoxicity was observed in WI-38 lung fibroblasts cells in vitro. The peptide fraction also revealed much better antioxidant activity toward peroxyl radicals and LDL than those of Trolox. Among these peptides, a potent antiproliferative, antioxidant, and NO-production-inhibiting hendecapeptide was isolated, and its amino acid sequence was VECYGPNRPQF. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce anticancer peptides. PMID:19916544

  11. Blue-green algae

    MedlinePlus

    ... Talk with your health provider.Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)Blue-green algae might slow blood clotting. Taking blue-green algae along with medications that ...

  12. Magnetic separation of algae

    DOEpatents

    Nath, Pulak; Twary, Scott N.

    2016-04-26

    Described herein are methods and systems for harvesting, collecting, separating and/or dewatering algae using iron based salts combined with a magnetic field gradient to separate algae from an aqueous solution.

  13. 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

  14. 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.

  15. Influence of cetyltrimethyl ammonium bromide on nutrient uptake and cell responses of Chlorella vulgaris.

    PubMed

    Liang, Zhijie; Ge, Fei; Zeng, Hui; Xu, Yin; Peng, Fang; Wong, Minghung

    2013-08-15

    The removal of nutrients by algae is regarded as a vital process in wastewater treatment, however algal cell activity can be inhibited by some toxic chemicals during the biological process. This study investigated the uptake of ammonia nitrogen (NH₄⁺) and total phosphorus (TP) by a green alga (Chlorella vulgaris) and algal cell responses under the stress of cetyltrimethyl ammonium bromide (CTAB), a representative for quaternary ammonium compounds (QACs, cationic surfactants). When the concentration of CTAB increased from 0 to 0.6 mg/L, the uptake efficiencies of NH₄⁺ and TP decreased from 88% to 18% and from 96% to 15%, respectively. Algal cell responses showed a decline in photosynthesis activity as indicated by the increase of chlorophyll autofluorescence from 2.9 a.u. to 25.3 a.u.; and a decrease of cell viability from 88% to 51%; and also a drop in esterase activity as indicated by the decrease in fluorescence of fluorescein diacetate stained cells from 71.5 a.u. to 4.7 a.u. Additionally, a transcription and translation response was confirmed by an enhancement of PO peak and amide II peak in algal cellular macromolecular composition stimulated by CTAB. The results suggest that QACs in wastewater may inhibit nutrient uptake by algae significantly through declining algal cell activities. PMID:23721850

  16. Dewatering of Chlorella pyrenoidosa using diatomite dynamic membrane: filtration performance, membrane fouling and cake behavior.

    PubMed

    Zhang, Yalei; Zhao, Yangying; Chu, Huaqiang; Zhou, Xuefei; Dong, Bingzhi

    2014-01-01

    The diatomite dynamic membrane (DDM) was utilized to dewater Chlorella pyrenoidosa of 2 g dry weight/L under continuous-flow mode, whose ultimate algae concentration ranged from 43 g to 22 g dry weight/L of different culture time. The stable flux of DDM could reach 30 L/m(2) h over a 24 h operation time without backwash. Influences of extracellular organic matters (EOM) on filtration behavior and membrane fouling were studied. The DDM was divided into three sub-layers, the slime layer, the algae layer and the diatomite layer from the outside to the inside of the cake layer based on components and morphologies. It was found that EOM caused membrane fouling by accumulating in the slime and algae layers. The DDM intercepted polysaccharides, protein-like substances, humic-like substances and some low-MW organics. Proteins were indicated the major membrane foulants with increased protein/polysaccharide ratio from the slime layer to the diatomite layer as culture time increased. This method could be applied to subsequent treatment of microalgae coupling technology of wastewater treatment or microalgae harvesting for producing biofuel. PMID:24148755

  17. 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

  18. Acute and chronic toxic effects of bisphenol A on Chlorella pyrenoidosa and Scenedesmus obliquus.

    PubMed

    Zhang, Wei; Xiong, Bang; Sun, Wen-Fang; An, Shuai; Lin, Kuang-Fei; Guo, Mei-Jin; Cui, Xin-Hong

    2014-06-01

    The acute and chronic toxic effects of Bisphenol A (BPA) on Chlorella pyrenoidosa (C. pyrenoidosa) and Scenedesmus obliquus (S. obliquus) were not well understood. The indoor experiments were carried out to observe and analyze the BPA-induced changes. Results of the observations showed that in acute tests BPA could significantly inhibit the growth of both algae, whereas chronic exposure hardly displayed similar trend. Superoxide dismutase (SOD) and Catalase (CAT) activities of both algae were promoted in all the treatments. Chlorophyll a synthesis of the two algae exhibited similar inhibitory trend in short-term treatments, and in chronic tests C. pyrenoidosa hardly resulted in visible influence, whereas in contrast, dose-dependent inhibitory effects of S. obliquus could be clearly observed. The experimental results indicated that the growth and Chlorophyll a syntheses of S.obliquus were more sensitive in response to BPA than that of C. pyrenoidosa, whereas for SOD andCAT activities, C. pyrenoidosa was more susceptible. This research provides a basic understanding of BPA toxicity to aquatic organisms. PMID:22887798

  19. The toxicity of naphthalene to marine Chlorella vulgaris under different nutrient conditions.

    PubMed

    Kong, Qingxia; Zhu, Lizhong; Shen, Xueyou

    2010-06-15

    The toxicity of naphthalene to Chlorella vulgaris was studied under nitrogen (N)-, phosphorus (P)-enriched and N,P-starved condition. Results showed that naphthalene was less toxic under N,P-starved condition. The inhibitory rates were less than 15.3% to C. vulgaris during 7 days exposure with the initial concentrations of naphthalene at 5, 10, 50, 100mg/L, respectively under N,P-starved condition, while they were 7.5-72.3% under N,P-enriched condition. The malondialdehyde (MDA) content indicated that there was no oxidative damage to algae when the initial concentration of naphthalene was less than 10mg/L, and oxidative damage exhibited to algae at 50-100mg/L of naphthalene under N,P-starved condition. Naphthalene induced oxidative damage to the algae at all tested concentrations (5-100mg/L) under N,P-enriched condition. The results indicated that there was a negative relationship between the special growth rate (SGR) and naphthalene concentration in the medium. Under N,P-enriched condition SGR of the control decreased slowly from 0.669 to 0.186. However, SGR of the naphthalene treated group decreased sharply during the first 2-3 days when the dissolved concentration of naphthalene was above 0.1mg/L, and then increased gradually with the evaporation of naphthalene. PMID:20133058

  20. Interest of dynamic tests in acute ecotoxicity assessment in algae

    SciTech Connect

    Jouany, J.M.; Ferard, J.F.; Vasseur, P.; Gea, J.; Truhaut, R.; Rast, C.

    1983-04-01

    Sorption of toxics by algae may be important and occurs very early. Thus, a decrease of the experimental toxic concentrations in the medium results in understating toxicity when tests are conducted under static conditions. In this work, two different methods of exposure of algae (Chlorella vulgaris) are studied, the static test and the pseudodynamic test. Acute effects (biological and analytical effects) of inorganic compounds (Cu/sup 2 +/, Cd/sup 2 +/, Pb/sup 2 +/, Cr/sup 6 +/) have been evaluated for 96 hr of exposure; in each case, IC50 is much lower in the dynamic condition than in the static one. The percentage of reduction varies from 55 to 75% after 96 hr. Accumulation of metal by chlorellae is greater when testing by the pseudodynamic way, with Cu/sup 2 +/ and Pb/sup 2 +/. But in the case of Cd/sup 2 +/ and Cr/sup 6 +/, the concentration factors are similar in the two kinds of exposure. These results point out the advantage of the pseudodynamic test, of which the methodology is very easy, for a more realistic assessment of acute ecotoxicity in these organisms.

  1. 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

  2. Removal of malachite green from aqueous solution using low-cost chlorella-based biomass.

    PubMed

    Tsai, Wen-Tien; Chen, Huei-Ru

    2010-03-15

    Chlorella-based biomass from the algae-manufacturing waste was used as a low-cost biosorbent for the biosorption of malachite green (MG) in an agitated batch experiments with respect to its kinetics as a function of agitation speed (i.e., 300-500 rpm), initial MG concentration (i.e., 2.0-20.0 mg dm(-3)), biosorbent loading (i.e., 0.5-2.0 g/2.0 dm(3)), initial pH (i.e., 3.0-11.0), and temperature (i.e., 278-318 K). The experimental data revealed that the rapid removal of cationic solute using the dead microalgae significantly depended on the initial MG concentration and algal loading. Furthermore, the biosorption kinetics well obeyed the pseudo-second-order rate equation, and could be elucidated by considering the electrostatic interactions. According to the biosorption behaviors of MG from aqueous solution using chlorella-based biomass in comparison with commercial activated carbon, this work also showed that the biosorbent can be effectively used as a low-cost biosorbent for the removal of MG from its aqueous solutions. PMID:19939553

  3. Effect of Chlorella intake on Cadmium metabolism in rats.

    PubMed

    Shim, Jee Ae; Son, Young Ae; Park, Ji Min; Kim, Mi Kyung

    2009-01-01

    This study was performed to investigate the effect of chlorella on cadmium (Cd) toxicity in Cd- administered rats. Sixty male Sprague-Dawley rats (14 week-old) were blocked into 6 groups. Cadmium chloride was given at levels of 0 or 325 mg (Cd: 0, 160 ppm), and chlorella powder at levels of 0, 3 and 5%. Cadmium was accumulated in blood and tissues (liver, kidney and small intestine) in the Cd-exposed groups, while the accumulation of Cd was decreased in the Cd-exposed chlorella groups. Fecal and urinary Cd excretions were remarkably increased in Cd-exposed chlorella groups. Thus, cadmium retention ratio and absorption rate were decreased in the Cd exposed chlorella groups. Urinary and serum creatinine, and creatinine clearance were not changed in experimental animals. In addition, metallothionein (MT) synthesis in tissues was increased by Cd administration. The Cd-exposed chlorella groups indicated lower MT concentration compared to the Cd-exposed groups. Moreover, glomerular filtration rate (GFR) was not changed by dietary chlorella and Cd administration. According to the results above, this study could suggest that Cd toxicity can be alleviated by increasing Cd excretion through feces. Therefore, when exposed to Cd, chlorella is an appropriate source which counteracts heavy metal poisoning, to decrease the damage of tissues by decreasing cadmium absorption. PMID:20016697

  4. 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

  5. Genome scale metabolic reconstruction of Chlorella variabilis for exploring its metabolic potential for biofuels.

    PubMed

    Juneja, Ankita; Chaplen, Frank W R; Murthy, Ganti S

    2016-08-01

    A compartmentalized genome scale metabolic network was reconstructed for Chlorella variabilis to offer insight into various metabolic potentials from this alga. The model, iAJ526, was reconstructed with 1455 reactions, 1236 metabolites and 526 genes. 21% of the reactions were transport reactions and about 81% of the total reactions were associated with enzymes. Along with gap filling reactions, 2 major sub-pathways were added to the model, chitosan synthesis and rhamnose metabolism. The reconstructed model had reaction participation of 4.3 metabolites per reaction and average lethality fraction of 0.21. The model was effective in capturing the growth of C. variabilis under three light conditions (white, red and red+blue light) with fair agreement. This reconstructed metabolic network will serve an important role in systems biology for further exploration of metabolism for specific target metabolites and enable improved characteristics in the strain through metabolic engineering. PMID:26995318

  6. Some observations on the carbon dioxide burst in chlorella and chlamydomonas.

    PubMed

    Bunt, J S

    1970-02-01

    In the course of mass spectrometer studies with the algae Chlorella and Chlamydomonas, data were obtained which indicate that the CO(2) burst and gulp are sensitive to oxygen. Furthermore, the CO(2) burst was found to be strongly suppressed when wave lengths shorter than 460 nanometers were blocked at intensities adequate to saturate photosynthesis. Under appropriate conditions at 30 degrees , the CO(2) burst was interrupted by a brief CO(2) gulp and the post illumination gulp by a brief burst of CO(2). The post illumination gulp of CO(2) could be induced during illumination by interposition of a filter blocking wave lengths shorter than 460 nanometers. These data are discussed in relation to earlier reports of the phenomenon and briefly as they affect the detection of photorespiration. PMID:16657291

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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/-.

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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

  18. Semi-continuous cultivation of Chlorella vulgaris for treating undigested and digested dairy manures.

    PubMed

    Wang, Liang; Wang, Yingkuan; Chen, Paul; Ruan, Roger

    2010-12-01

    The present study, based on a previous batch-wise experiment, investigated a lab-scale semi-continuous cultivation of green microalgae Chlorella vulgaris (UTEX 2714), as a useful means for nutrient reduction as well as production of algal biomass which can be used as potential feedstock for the production of biofuel and other commodities, on 20 x diluted dairy manures. Both undigested and digested samples were applied in parallel experiments for comparison regarding the requirements of hydraulic retention times (HRTs), removal efficiencies of nitrogen, phosphorus, and chemical oxygen demand (COD), biomass productivities, and CO₂ sequestration abilities. It was demonstrated that algae grown in undigested dairy manure achieved removal rates of 99.7%, 89.5%, 92.0%, and 75.5% for NH₄+--N, TN, TP, and COD, respectively, under a 5-day HRT, while the HRT had to extend to 20 days in order to achieve 100.0% removal of NH₄+--N in digested one with simultaneous removals of 93.6% of TN, 89.2% of TP, and 55.4% of COD. The higher organic carbon contained in undigested dairy manure helped boost the growth of mixotrophic Chlorella, thus resulting in a much shorter HRT needed for complete removal of NH₄+--N. Moreover, algae grown in digested dairy manure provided more penitential than those grown in undigested one in CO₂ sequestration per milligram of harvested dried biomass (1.68 mg CO₂/mg dry weight (DW) vs 0.99 mg CO₂/mg DW), but did not surpass in total the amount of CO₂ sequestered on a 15-day period basis because of the better productivity gained in undigested dairy manure. PMID:20567935

  19. 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

  20. 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

  1. Is annual metabolic cycling in the unicellular microalgae Chlorella and textit{Isochrysis} coupled to the annual earth gravity cycle?

    NASA Astrophysics Data System (ADS)

    Knutsen, G.; Amundsen, M.; Pettersen, R.

    Uptake rates of 14C-labelled guanine by autospores of the unicellular green alga Chlorella fusca Shihira et Krauss were measured at different times over 21 months. The autospores were derived from synchronous cultures produced from stock cultures that had not been exposed to natural light the last six years before the experiments, nor during the 21 month long experimental period. The experiments were performed in Bergen, Norway (60°,23' N; 5°,20' E). Uptake rates showed distinct annual variations over the year, with lowest values during the winter and highest during the summer. The August : December : February ratios for the rates were 1.0, 0.70 and 0.43, respectively. Half saturating guanine concentration for the uptake was the same over the year, namely 0.24 μM. Growth rates of the unicellular marine flagellate Isochrysis sp. were measured in March, August and December, and the rates were distinctly different, with August : December : March ratios of 1.0, 0.41 and 0.64. The number of cells reached in the stationary phases of Isochrysis cultures showed similar time-of-the-year dependency with ratios of 1.0, 0.44 and 0.58 for August : December : March, respectively. These cells had not experienced day light for the two last years before the experiments. Our results show the existence of annual rhythms in two microalgae that had not been exposed to natural light for a long time. A persistent endogenous clock that was set when the cells lived under natural light conditions long ago may be one explanation for their behaviour; another one is a coupling to the sinusoidal and minute variation over the year of earth gravity. Hence the cells display maximal activity when gravity is at its lowest value during the summer in the Northern hemisphere, and lowest activity when the gravity is at is highest in the winter. To our knowledge our results are the first experimental work that points to the possibility that cells may be influenced by the annual cycle of earth gravity.

  2. Effect of tetramethyl lead on freshwater green algae.

    PubMed

    Silverberg, B A; Wong, P T; Chau, Y K

    1977-01-01

    The toxicity of tetramethyl lead (Me4Pb) towards freshwater algae was studied by bubbling biologically generated Me4Pb from one flask containing 5 mg of Pb 1-1 as Me3PbOAc into the culture medium in another flask where a test alga Scenedesmus quadricauda was grown. As Me4Pb is not soluble in water and is volatile, the exposure of an alga to this lead compound was only momentary. It was estimated that less than 0.5 mg of Pb(Me4Pb) had passed through the culture medium. The primary productivity and cell growth (determined by dry weight), however, decreased by 85% and 32% respectively, as compared with the controls without exposure to Me4Pb. Furthermore, cells exposed to Me4Pb tended to clump together and striking alterations in cell fine-structure were observed. An electron microscopic analysis by an energy dispersive spectrometer revealed that Pb ions had penetrated the cell and were deposited within concretion bodies. Similar results were obtained with the green algae Ankistrodesmus falcatus and Chlorella pyrenoidosa. PMID:869587

  3. Effects of algae on the efficacy of Bacillus thuringiensis var. israelensis against larval black flies.

    PubMed

    Stephens, Marianne S; Overmyer, Jay P; Gray, Elmer W; Noblet, Ray

    2004-06-01

    Personnel from several black fly control programs have reported that the efficacy of Bacillus thuringiensis var. israelesis (Bti) is reduced during periods when algal concentrations are high in the waterways. Although the reduction in Bti-induced mortality in black fly larvae is presumed to be related to the presence of algae, no scientific data support this theory. In this study, 4 genera of algae (Microcytis, Scenedesmus, Dictrosphaerium, and Chlorella) commonly detected in Pennsylvania rivers where Bti-induced mortality in black fly larvae has been reduced were assessed to determine their respective effects on Bti-induced mortality by using an orbital shaker bioassay with laboratory-reared black fly larvae (Simulium vittatum cytospecies IS-7). A significant reduction in Bti-induced mortality was observed when Scenedesmus was present in the flasks at concentrations > or = 16,000 cells/ml. The Bti-induced mortality of larvae was not significantly reduced when Chlorella, Dictyosphaerium, or Microcytis was present in the flasks, even at concentrations > or = 250,000 cells/ml. These results indicate that the presence of certain types of algae can reduce the mortality of black flies exposed to Bti. Although not clearly defined, the mechanisms involved may be related to algal morphology due to overall size and structures associated with certain types of algae, and possible interference with feeding. PMID:15264627

  4. Basis for the Resistance of Several Algae to Microbial Decomposition

    PubMed Central

    Gunnison, Douglas; Alexander, Martin

    1975-01-01

    The basis for the resistance of certain algae to microbial decomposition in natural waters was investigated using Pediastrum duplex, Staurastrum sp., and Fischerella muscicola as test organisms. Enzyme preparations previously found to convert susceptible algae into spheroplasts had no such effect on the resistant species, although glucose and galacturonic acid were released from P. duplex walls. Little protein or lipid but considerable carbohydrate was found in the walls of the refractory organisms, but resistance was not correlated with the presence of a unique sugar monomer. A substance present in Staurastrum sp. walls was characterized as lignin or lignin-like on the basis of its extraction characteristics, infrared spectrum, pyrolysis pattern, and content of an aromatic building block. Sporopollenin was found in P. duplex, and cellulose in Staurastrum sp. Cell walls of the algae were fractionated, and the fractions least susceptible to microbial degradation were the sporopollenin of P. duplex, the polyaromatic component of Staurastrum sp., and two F. muscicola fractions containing several sugar monomers. The sporopollenin content of P. duplex, the content of lignin or a related constituent of Staurastrum sp., and the resistance of the algae to microbial attack increased with age. It is suggested that resistance results from the presence of sporopollenin in P. duplex, a lignin-like material in Staurastrum sp., and possibly heteropolysaccharides in F. muscicola. PMID:808166

  5. A model describing the time course and variability in toxicity of hydrophobic chemicals to aquatic organisms. Toxicity of chlorinated benzenes to marine algae

    NASA Astrophysics Data System (ADS)

    Xiulin, Wang; Baotian, Shan; Ming, Ge; Lei, Zhang; Chenjian, Zhu; Xiurong, Han

    2002-04-01

    The growth of Chlorella marine, Nannochloris oculate, Pyramimonaos sp., Platymonas subcordiformis and Phaeodactylum tricornutum exposed to chlorobenzene, 1,2-dichlorobenzene, 1,2,3,4-tetrachlorobenzene and pentachlorobenzene was tested. The Boltzman equation was used to describe organism growth. The time course for uptake of hydrophobic organic chemicals (HOCs) by aquatic organisms was expressed by incorporating growth and, if desired, the effect of metabolism into the HOC bioconcentration process. The probability of any given concentration of HOCs in the organisms causing a specified toxic endpoint was expressed with a modified Weibull distribution function. The combined bioconcentration and probability equations were tested with data for time course of incubation of algae exposed to chlorinated benzenes (CBs). A set of parameters, including the uptake rate constant k 1, the elimination rate constant k 2 and thereafter the bioconcentration factor on a dry weight basis, BCF D, the critical HOC concentration in the organism resulting in a specified toxic endpoint, C {A/*}, and the spread factor, S, could be obtained by fitting only experimental data for percent growth inhibition(%)-time-CB exposure concentration. The average coefficients of variation within CBs were 15.2% for BCF D, 21.0% for k 1, 18.3% for k 2, 8.1% for C {A/*} and 9.7% for S. The variability in toxicity (such as EC10, EC50, EC90) derived from the model equations agreed well with those experimentally observed.

  6. Landfill leachate--a water and nutrient resource for algae-based biofuels.

    PubMed

    Edmundson, Scott J; Wilkie, Ann C

    2013-01-01

    There is a pressing need for sustainable renewable fuels that do not negatively impact food and water resources. Algae have great potential for the production of renewable biofuels but require significant water and fertilizer resources for large-scale production. Municipal solid waste (MSW) landfill leachate (LL) was evaluated as a cultivation medium to reduce both water and elemental fertilizer demands of algae cultivation. Daily growth rate and cell yield of two isolated species of algae (Scenedesmus cf. rubescens and Chlorella cf. ellipsoidea) were cultivated in MSW LL and compared with Bold's Basal Medium (BBM). Results suggest that LL can be used as a nutrient resource and medium for the cultivation of algae biomass. S. cf. rubescens grew well in 100% LL, when pH was regulated, with a mean growth rate and cell yield 91.2% and 92.8% of those observed in BBM, respectively. S. cf. rubescens was more adaptable than C. cf. ellipsoidea to the LL tested. The LL used in this study supported a maximum volumetric productivity of 0.55 g/L/day of S. cf. rubescens biomass. The leachate had sufficient nitrogen to supply 17.8 g/L of algae biomass, but was limited by total phosphorus. Cultivation of algae on LL offsets both water and fertilizer consumption, reducing the environmental footprint and increasing the potential sustainability of algae-based biofuels. PMID:24350438

  7. Role of extracellular polymeric substances from Chlorella vulgaris in the removal of ammonium and orthophosphate under the stress of cadmium.

    PubMed

    Chen, Biao; Li, Feng; Liu, Na; Ge, Fei; Xiao, Huaixian; Yang, Yixuan

    2015-08-01

    The interactions between the soluble extracellular polymeric substances (S-EPS), bound EPS (B-EPS) of algae and heavy metal, would affect the removal of ammonium (NH4(+)-N) and orthophosphate (PO4(3-)-P) from wastewater by algae-based techniques. This study investigated the role of Cd(2+)-mediated EPS from Chlorella vulgaris on NH4(+)-N and PO4(3-)-P removal. The results showed that the removal efficiencies of NH4(+)-N and PO4(3-)-P still separately remained 62.6% and 64.9% under 1.0mg/L Cd(2+), compared to those without Cd(2+), mainly attributing to enhanced S-EPS and B-EPS contents of the algae. The increased of PS (polysaccharides) and PN (proteins, e.g., tryptophan-like and tyrosine-like components) led to accelerated interactions of Cd(2+) with PS and PN in EPS fractions, especially for B-EPS, due to a higher detected distribution of Cd(2+) (e.g., about 55.4% in B-EPS). Thus, algae-based techniques are stable treatment methods for wastewater in which NH4(+)-N and PO4(3-)-P coexist with heavy metals. PMID:25965255

  8. One alga to rule them all: unrelated mixotrophic testate amoebae (amoebozoa, rhizaria and stramenopiles) share the same symbiont (trebouxiophyceae).

    PubMed

    Gomaa, Fatma; Kosakyan, Anush; Heger, Thierry J; Corsaro, Daniele; Mitchell, Edward A D; Lara, Enrique

    2014-03-01

    Endosymbiosis is a central and much studied process in the evolution of eukaryotes. While plastid evolution in eukaryotic algae has been extensively studied, much less is known about the evolution of mixotrophy in amoeboid protists, which has been found in three of the five super groups of Eukaryotes. We identified the green endosymbionts in four obligate mixotrophic testate amoeba species belonging to three major eukaryotic clades, Hyalosphenia papilio and Heleopera sphagni (Amoebozoa: Arcellinida), Placocista spinosa (Rhizaria: Euglyphida), and Archerella flavum (Stramenopiles: Labyrinthulomycetes) based on rbcL (ribulose-1,5-diphosphate carboxylase/oxygenase large subunit) gene sequences. We further investigated whether there were different phylotypes of algal endosymbionts within single H. papilio cells and the degree of host-symbiont specificity by amplifying two genes: COI (mitochondrial cytochrome oxydase subunit 1) from the testate amoeba host, and rbcL from the endosymbiont. Results show that all studied endosymbionts belong to genus Chlorella sensu stricto, closely related to Paramecium bursaria Chlorella symbionts, some lichen symbionts and also several free-living algae. Most rbcL gene sequences derived from symbionts from all testate amoeba species were almost identical (at most 3 silent nucleotides difference out of 780 bp) and were assigned to a new Trebouxiophyceae taxon we named TACS (Testate Amoeba Chlorella Symbionts). This "one alga fits all mixotrophic testate amoeba" pattern suggests that photosynthetic symbionts have pre-adaptations to endosymbiosis and colonise diverse hosts from a free-living stage. PMID:24646792

  9. [Harmful algae and health].

    PubMed

    Kankaanpää, Harri T

    2011-01-01

    Harmful algae are a worldwide problem. Phycotoxins is a general term for toxic compounds produced by harmful species of the phytoplankton. This review deals with the occurrence of harmful algae and phycotoxins in the Baltic Sea and other domestic waters, the ways of getting exposed to them, and their effects. Advice on how to avoid the exposure is provided. PMID:21834336

  10. Algae Derived Biofuel

    SciTech Connect

    Jahan, Kauser

    2015-03-31

    One of the most promising fuel alternatives is algae biodiesel. Algae reproduce quickly, produce oils more efficiently than crop plants, and require relatively few nutrients for growth. These nutrients can potentially be derived from inexpensive waste sources such as flue gas and wastewater, providing a mutual benefit of helping to mitigate carbon dioxide waste. Algae can also be grown on land unsuitable for agricultural purposes, eliminating competition with food sources. This project focused on cultivating select algae species under various environmental conditions to optimize oil yield. Membrane studies were also conducted to transfer carbon di-oxide more efficiently. An LCA study was also conducted to investigate the energy intensive steps in algae cultivation.

  11. 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

  12. Investigation of high pressure steaming (HPS) as a thermal treatment for lipid extraction from Chlorella vulgaris.

    PubMed

    Aguirre, Ana-Maria; Bassi, Amarjeet

    2014-07-01

    Biofuels from algae are considered a technically viable energy source that overcomes several of the problems present in previous generations of biofuels. In this research high pressure steaming (HPS) was studied as a hydrothermal pre-treatment for extraction of lipids from Chlorella vulgaris, and analysis by response surface methodology allowed finding operational points in terms of target temperature and algae concentration for high lipid and glucose yields. Within the range covered by these experiments the best conditions for high bio-crude yield are temperatures higher than 174°C and low biomass concentrations (<5 g/L). For high glucose yield there are two suitable operational ranges, either low temperatures (<105°C) and low biomass concentrations (<4 g/L); or low temperatures (<105°C) and high biomass concentrations (<110 g/L). High pressure steaming is a good hydrothermal treatment for lipid recovery and does not significantly change the fatty acids profile for the range of temperatures studied. PMID:24852645

  13. Metabolic control of urea catabolism in Chlamydomonas reinhardi and Chlorella pyrenoidosa.

    PubMed

    Hodson, R C; Williams, S K; Davidson, W R

    1975-03-01

    In the unicellular green alga Chlamydomonas reinhardi (strain y-1), synthesis of the enzymes required for urea hydrolysis is under substrate induction control by urea and under end product repression control by ammonia. Hydrolysis of urea if effected by the sequential action of the discrete enzymes urea carboxylase and allophanate lyase, collectively called urea amidolyase. The carboxylase converts urea to allophanate in a reaction requiring biotin, adenosine 5'-triphosphate, and Mg2+. The lyase hydrolzyes allophanate to ammonium ions and bicarbonate. Neither activity is present in more than trace amounts when cultures are grown with ammonia or urea plus ammonia, or when they are starved for nitrogen for 8 h. Urea in the absence of ammonia induces both activities 10 to 100 times the basal levels. Addition of ammonia to an induced culture causes complete cessation of carboxylase accumulation and an 80% depression of lyase accumulation. Ammonia does not reduce urea uptake by repressed cells, so it does not prevent induction by the mechanism of inducer exclusion. The unicellular green alga Chlorella pyrenoidosa (strain 3 Emerson) also has discrete carboxylase and lyase enzymes, but only the carboxylase exhibits metabolic control. PMID:1116994

  14. 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

  15. 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.

  16. 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

  17. Strain selection, biomass to biofuel conversion, and resource colocation have strong impacts on the economic performance of algae cultivation sites

    SciTech Connect

    Venteris, Erik R.; Wigmosta, Mark S.; Coleman, Andre M.; Skaggs, Richard

    2014-09-16

    Decisions involving strain selection, biomass to biofuel technology, and the location of cultivation facilities can strongly influence the economic viability of an algae-based biofuel enterprise. In this contribution we summarize our past results in a new analysis to explore the relative economic impact of these design choices. We present strain-specific growth model results from two saline strains (Nannocloropsis salina, Arthrospira sp.), a fresh to brackish strain (Chlorella sp., DOE strain 1412), and a freshwater strain of the order Sphaeropleales. Biomass to biofuel conversion is compared between lipid extraction (LE) and hydrothermal liquefaction (HTL) technologies. National-scale models of water, CO2 (as flue gas), land acquisition, site leveling, construction of connecting roads, and transport of HTL oil to existing refineries are used in conjunction with estimates of fuel value (from HTL) to prioritize and select from 88,692 unit farms (UF, 405 ha in pond area), a number sufficient to produce 136E+9 L yr-1 of renewable diesel (36 billion gallons yr-1, BGY). Strain selection and choice of conversion technology have large economic impacts, with differences between combinations of strains and biomass to biofuel technologies being up to $10 million dollars yr-1 UF-1. Results based on the most productive species, HTL-based fuel conversion, and resource costs show that the economic potential between geographic locations within the selection can differ by up to $4 million yr-1 UF-1, with 2.0 BGY of production possible from the most cost-effective sites. The local spatial variability in site rank is extreme, with very high and low rank sites within 10s of km of each other. Colocation with flue gas sources has a strong influence on site rank, but the most costly resource component varies from site to site. The highest rank sites are located predominantly in Florida and Texas, but most states south of 37°N latitude contain promising locations. Keywords: algae

  18. Algicidal Effect of Bromine and Chlorine on Chlorella pyrenoidosa

    PubMed Central

    Kott, Yehuda; Hershkovitz, Galila; Shemtob, A.; Sless, J. B.

    1966-01-01

    Chlorella pyrenoidosa was found to grow rapidly in tap water. Peak growth was reached after 2 to 3 days. Chlorine and bromine, added to such water, were shown to be effective inhibitors of algal growth. Bromine and bromamine were primarily algicidal, whereas chlorine and chloramines were mainly algistatic. It is assumed that the mechanisms of action of these halogens on Chlorella are not the same. PMID:5914499

  19. CONTRIBUTION OF MARINE ALGAE TO TRIHALOMETHANE PRODUCTION IN CHLORINATED ESTUARINE WATER

    EPA Science Inventory

    Three species of marine algae representing major taxonomic groups of phytoplankton, Isochrysis galbana (Chrysophyceae), Carteria sp. (Chlorophyceae), and Thalassiosira pseudonana (Bacillariphyceae), were utilized to investigate the potential of natural occurring chlorophyll a of ...

  20. Controlled introduction of selenium into Chlorella cells.

    PubMed

    de Alcantara, S; Lopes, C C; Wagener, K

    1998-12-01

    Selenium (Se) is an important element in the antioxidant system of the human body, and Chlorella, well-known for its therapeutic effects, is the ideal carrier to offer it in the wanted organic form. The kinetics of Se absorption by growing algal cells and its distribution in the cells are studied using radioactive 75Se labelled solutions. There is a rapid Se absorption within the first few minutes at the cell surfaces where it is irreversibly fixed and cannot be absorbed by the human body. In the final state, reached after 24-48 hr, about 40% of the total fixed Se is inside the cells in the wanted organic-bound form. PMID:10093514

  1. Coagulation-membrane filtration of Chlorella vulgaris.

    PubMed

    Lee, Duu-Jong; Liao, Guan-Yu; Chang, Yin-Ru; Chang, Jo-Shu

    2012-03-01

    Filtration-based separation of Chlorella vulgaris, a species with excellent potential for CO(2) capture and lipid production, was investigated using a surface-modified hydrophilic polytetrafluoroethylene (PTFE) membrane. Coagulation using polyaluminum chloride (PACl) attained maximum turbidity removal at 200 mg L(-1) as Al(2)O(3). The membrane filtration flux at 1 bar increased as the PACl dose increased, regardless of overdosing in the coagulation stage. The filtered cake at the end of filtration tests peaked in solid content at 10 mg L(-1) as Al(2)O(3), reaching 34% w/w, roughly two times that of the original suspension. Differential scanning calorimetry (DSC) tests demonstrate that the cake with minimum water-solid binding strength produced the driest filter cake. Coagulation using 10 mg L(-1) PACl as Al(2)O(3), followed by PTFE membrane filtration at 1 bar, is an effective process for harvesting C. vulgaris from algal froth. PMID:22261659

  2. Identification of cypermethrin induced protein changes in green algae by iTRAQ quantitative proteomics.

    PubMed

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

    2016-04-29

    Cypermethrin (CYP) is one of the most widely used pesticides in large scale for agricultural and domestic purpose and the residue often seriously affects aquatic system. Environmental pollutant-induced protein changes in organisms could be detected by proteomics, leading to discovery of potential biomarkers and understanding of mode of action. While proteomics investigations of CYP stress in some animal models have been well studied, few reports about the effects of exposure to CYP on algae proteome were published. To determine CYP effect in algae, the impact of various dosages (0.001μg/L, 0.01μg/L and 1μg/L) of CYP on green algae Chlorella vulgaris for 24h and 96h was investigated by using iTRAQ quantitative proteomics technique. A total of 162 and 198 proteins were significantly altered after CYP exposure for 24h and 96h, respectively. Overview of iTRAQ results indicated that the influence of CYP on algae protein might be dosage-dependent. Functional analysis of differentially expressed proteins showed that CYP could induce protein alterations related to photosynthesis, stress responses and carbohydrate metabolism. This study provides a comprehensive view of complex mode of action of algae under CYP stress and highlights several potential biomarkers for further investigation of pesticide-exposed plant and algae. PMID:26961939

  3. The Selective Use of Hypochlorite to Prevent Pond Crashes for Algae-Biofuel Production.

    PubMed

    Park, Sichoon; Van Ginkel, Steven W; Pradeep, Priya; Igou, Thomas; Yi, Christine; Snell, Terry; Chen, Yongsheng

    2016-01-01

    Although algae-biofuels have many advantages including high areal productivity, algae can be preyed upon by amoebas, protozoans, ciliates, and rotifers, particularly in open pond systems. Thus, these higher organisms need to be controlled. In this study, Chlorella kessleri was used as the algal culture and Brachionus calyciflorus as the source of predation. The effect of sodium hypochlorite (bleach) was tested with the goal of totally inhibiting the rotifer while causing minor inhibition to the alga. The 24-hr LC(50) for B. calyciflorus in spring water was 0.198 mg Cl/L while the 24-hr LC(50) for C. kessleri was 0.321 mg Cl/L. However, chlorine dissipates rapidly as the algae serves as reductant. Results showed a chlorine dosage between 0.45 to 0.6 mg Cl/L and a dosing interval of two hours created the necessary chlorine concentrations to inhibit predation while letting the algae grow; thus giving algae farmers a tool to prevent pond crashes. PMID:26803029

  4. Toxicity of haloacetic acids to freshwater algae.

    PubMed

    Roberts, Jayne F; van Egmond, Roger; Price, Oliver R

    2010-01-01

    Haloacetic acids (HAA), such as trichloroacetic acid (TCA), are commonly occurring by-products from disinfection and bleaching processes using sodium hypochlorite. Currently, the lowest no observed effect concentration (NOEC) for TCA is reported to be 8.7microgL(-1), which was derived from a toxicity study conducted in 1981 on Chlorella pyrenoidosa. The purity of the test material was not documented and it is unknown if other halogenated impurities or co-formulants were present. However, this NOEC is used to derive a predicted no effect concentration, which is used in various regulatory risk assessments. We present a range of algal toxicity studies conducted on five different algal species and two HAAs and observed no toxicity of TCA to C. pyrenoidosa at 115mgL(-1). The most sensitive species to TCA (NOEC, 3mgL(-1)) were Pseudokirchneriella subcapitata and Scenedesmus subspicatus, demonstrating that the toxicity of TCA to algae is over two orders of magnitude less sensitive than previously reported. PMID:19828197

  5. Direct transesterification of Oedogonium sp. oil be using immobilized isolated novel Bacillus sp. lipase.

    PubMed

    Sivaramakrishnan, Ramachandran; Muthukumar, Karuppan

    2014-01-01

    This work emphasizes the potential of the isolated Bacillus sp. lipase for the production of fatty acid methyl ester by the direct transesterification of Oedogonium sp. of macroalgae. Dimethyl carbonate was used as the extraction solvent and also as the reactant. The effect of solvent/algae ratio, water addition, catalyst, temperature, stirring and time on the direct transesterification was studied. The highest fatty acid methyl ester yield obtained under optimum conditions (5 g Oedogonium sp. powder, 7.5 ml of solvent (dimethyl carbonate)/g of algae, 8% catalyst (%wt/wt of oil), distilled water 1% (wt/wt of algae), 36 h, 55°C and 180 rpm) was 82%. Final product was subjected to thermogravimetric analysis and (1)H NMR analysis. The results showed that the isolated enzyme has good potential in catalyzing the direct transesterification of algae, and the dimethyl carbonate did not affect the activity of the isolated lipase. PMID:23890544

  6. Sludge-grown algae for culturing aquatic organisms: Part II. Sludge-grown algae as feeds for aquatic organisms

    NASA Astrophysics Data System (ADS)

    Wong, M. H.; Hung, K. M.; Chiu, S. T.

    1996-05-01

    This project investigated the feasibility of using sewage sludge to culture microalgae ( Chlorella-HKBU) and their subsequent usage as feeds for rearing different organisms. Part II of the project evaluated the results of applying the sludge-grown algae to feed Oreochromis mossambicus (fish), Macrobrachium hainenese (shrimp), and Moina macrocopa (cladocera). In general, the yields of the cultivated organisms were unsatisfactory when they were fed the sludge-grown algae directly. The body weights of O. mossambicus and M. macrocopa dropped 21% and 37%, respectively, although there was a slight increase (4.4%) in M. hainenese. However, when feeding the algal-fed cladocerans to fish and shrimp, the body weights of the fish and shrimp were increased 7% and 11% accordingly. Protein contents of the cultivated organisms were comparable to the control diet, although they contained a rather high amount of heavy metals. When comparing absolute heavy metal contents in the cultivated organisms, the following order was observed: alga > cladocera > shrimp, fish > sludge extracts. Bioelimination of heavy metals may account for the decreasing heavy metal concentrations in higher trophic organisms.

  7. 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.

  8. BIOCONCENTRATION OF A HEXACHLOROBIPHENYL IN GREAT LAKES PLANKTONIC ALGAE

    EPA Science Inventory

    The bioconcentration of 2,4,5,2',4',5'-hexachlorobiphenyl (HCB) was examined in the Great Lakes algae Fragilaria crotonensis, Ankistrodesmus falcatus, and Microcystis sp. The bioconcentration factors varied from species to species, whether they were expressed in terms of cell num...

  9. The plastid genome of the red alga Laurencia.

    PubMed

    Verbruggen, Heroen; Costa, Joana F

    2015-06-01

    We present the 174,935 nt long plastid genome of the red alga Laurencia sp. JFC0032. It is the third plastid genome characterized for the largest order of red algae (Ceramiales). The circular-mapping plastid genome is small compared to most florideophyte red algae, and our comparisons show a trend toward smaller plastid genome sizes in the family Rhodomelaceae, independent from a similar trend in Cyanidiophyceae. The Laurencia genome is densely packed with 200 annotated protein-coding genes (188 widely conserved, 3 open reading frames shared with other red algae and 9 hypothetical coding regions). It has 29 tRNAs, a single-copy ribosomal RNA cistron, a tmRNA, and the RNase P RNA. PMID:26986672

  10. 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.

  11. 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. PMID:25855090

  12. Characterisation Of Polysacharides And Lipids From Selected Green Algae Species By FTIR-ATR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bartošová, Alica; Blinová, Lenka; Gerulová, Kristína

    2015-06-01

    Fourier transform infrared (FTIR) spectroscopy was used in this study to identify and determine spectral features of Chromochloris zofingiensis (Dönz) Fucíková et L.A. Lewis (SAG 211-14, Gottingen, Germany), Acutodesmus obliguus (Turpin) Hegewald (SAG 276-1, Gottingen, Germany) and Chlorella sorokiniana (K. Brandt) Pröschold et Darienko (SAG 211-40c, Gottingen, Germany). Polysaccharides and lipids from these three algae species were determined using Fourier Transformed Infrared Spectroscopy (FTIR) with ATR accessory with diamante crystal in spectral range from 400 - 4000 cm-1 and resolution 4.

  13. Viruses of eukaryotic green algae. Progress report, August 1, 1984-March 1, 1986

    SciTech Connect

    Van Etten, J.L.

    1986-01-01

    PBCV-1 is a large dsDNA-containing, plaque forming virus that replicates in a unicellular, eukaryotic Chlorella-like green alga strain NC64A. We have discovered that PBCV-1 infection results in the appearance of a restriction and modification system in the host. Furthermore, we have isolated and partially characterized 30 additional large, dsDNA-containing viruses which replicate in the same host. Some, if not all, of these viruses probably induce the synthesis of modification and restriction systems which are different from that induced by PBCV-1. 16 refs.

  14. Use of oxygen-18 isotopic labeling to assay photorespiration in terrestrial plants and algae

    SciTech Connect

    de Veau, E.J.

    1988-01-01

    A new method was devised to quantify photorespiration. The assay utilized {sup 18}O{sub 2} to isotopically label intermediates of the glycolate pathway, specifically glycolate, glycine, and serine, for various time periods. The pathway intermediates were isolated and analyzed on a mass spectrometer to determine molecular percent {sup 18}O-enrichment. Rates of glycolate synthesis were determined from: {sup 18}O-labeling kinetics of the intermediates, derived rate equations, and non-linear regression techniques. The method was adapted to measure photorespiratory rates in both terrestrial plants and algae. Test plants are Triticum aestivum, Zea mays L., Pavlova lutheri and Chlorella pyrenoidosa.

  15. 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

  16. 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

  17. [Planktonic Algae's Distribution and Correlation with Dissolved Organic Matters' Fluorescence in the End of the Three Gorges Reservoir's Back Water Zone].

    PubMed

    Fan, Lei-lei; Li, Si; Yu, Dan-ni; He, Qiang; Ji, Fang-ying; Jiang, Zhong-yuan; Gao, Zhi-xi; Ao, Ke-hou

    2015-08-01

    For researching the community structure, composition, and distribution of the planktonic algae in the Three Gorges Reservoir (TRG), especially, within TRG water levels' fluctuating, mpacting to water quality with the algae's growing, 6 sampling cites in the end of the TGR's back water zone, from Chaotianmen to Taihonggang Town, are chosen to monitor, at the sensitive stages time of algal bloom between March to May 2012, namely, water levels lowing from the highest impounding. The community's structure, composition, and distribution of the planktonic algae in the TGR, and the correlation of water quality parameters and DOM's fluorescence features with algae density, are obtained. According to the experimental results, blue algae fibre, chlorella, melosira, navicula are the dominated algae in the end of the TGR's back water zone, from Chaotianmen to Taihonggang Town, algae density are 0.40~0.56 × 10(6), 1.9~0.8 × 10(6), 0.36~0.25 × 10(6), 0.42~0.15 × 10(6) cells · L(-1) respectively. Besides, anabaena, phormidium, cladophora, feather, ovate algae are existing in only limited 2 sections. The fitting results reveal obvious linear correlation of the EEM characteristics of DOM with the 4 kinds of dominated algal density, which could be useful conference for the algae bloom monitor, conveniently and effectively. PMID:26672293

  18. Genome-Based Metabolic Mapping and 13C Flux Analysis Reveal Systematic Properties of an Oleaginous Microalga Chlorella protothecoides

    SciTech Connect

    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 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 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

  19. Genome-Based Metabolic Mapping and 13C Flux Analysis Reveal Systematic Properties of an Oleaginous Microalga Chlorella protothecoides1[OPEN

    PubMed Central

    Wu, Chao; Xiong, Wei; Dai, Junbiao; Wu, Qingyu

    2015-01-01

    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 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 13C 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 13C labeling

  20. 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.

  1. Plasmodesmata of brown algae.

    PubMed

    Terauchi, Makoto; Nagasato, Chikako; Motomura, Taizo

    2015-01-01

    Plasmodesmata (PD) are intercellular connections in plants which play roles in various developmental processes. They are also found in brown algae, a group of eukaryotes possessing complex multicellularity, as well as green plants. Recently, we conducted an ultrastructural study of PD in several species of brown algae. PD in brown algae are commonly straight plasma membrane-lined channels with a diameter of 10-20 nm and they lack desmotubule in contrast to green plants. Moreover, branched PD could not be observed in brown algae. In the brown alga, Dictyota dichotoma, PD are produced during cytokinesis through the formation of their precursor structures (pre-plasmodesmata, PPD). Clustering of PD in a structure termed "pit field" was recognized in several species having a complex multicellular thallus structure but not in those having uniseriate filamentous or multiseriate one. The pit fields might control cell-to-cell communication and contribute to the establishment of the complex multicellular thallus. In this review, we discuss fundamental morphological aspects of brown algal PD and present questions that remain open. PMID:25516500

  2. Elimination of bicarbonate interference in the binding of U(VI) in mill-waters to freeze-dried Chlorella vulgaris

    SciTech Connect

    Greene, B.; Henzl, M.T.; Hosea, J.M.; Darnall, D.W.

    1986-01-01

    Freeze-dried preparations of Chlorella vulgaris will accumulate U(Vl) from alkaline, bicarbonate-containing waters collected from uranium mill process streams, provided that the pH is pre-adjusted to between 4.0 and 6.0. Bicarbonate ion complexes the uranyl ion in these waters and seriously interferes with the binding of U(Vl) to the algal cells at pH values above 6.0. No binding of U(Vl) to the algae occurred at the natural pH of 8.0 when Chlorella vulgaris was suspended in untreated mull-waters containing up to 2.5 x 10/sup -4/M U(Vl). However, when the pH of these waters was lowered from 8.0 to near 5.0, with nitric acid, nearly quantitative binding of U(Vl) to the alga was achieved. Binding is rapid and largely unaffected by ions including Na/sup +/, Cl/sup -/, NO/sub 3//sup -/, /sup -/OAc, and SO/sub 4//sup 2 -/. Our results indicate that provided steps are taken to eliminate bicarbonate interference, such as adjustment of the pH to near 5.0, dried algal biomass could prove useful for the removal and recovery of U(Vl) from high carbonate-containing waters.

  3. Culture of microalgae Chlorella minutissima for biodiesel feedstock production.

    PubMed

    Tang, Haiying; Chen, Meng; Garcia, M E D; Abunasser, Nadia; Ng, K Y Simon; Salley, Steven O

    2011-10-01

    Microalgae are among the most promising of non-food based biomass fuel feedstock alternatives. Algal biofuels production is challenged by limited oil content, growth rate, and economical cultivation. To develop the optimum cultivation conditions for increasing biofuels feedstock production, the effect of light source, light intensity, photoperiod, and nitrogen starvation on the growth rate, cell density, and lipid content of Chlorella minutissima were studied. The fatty acid content and composition of Chlorella minutissima were also investigated under the above conditions. Fluorescent lights were more effective than red or white light-emitting diodes for algal growth. Increasing light intensity resulted in more rapid algal growth, while increasing the period of light also significantly increased biomass productivity. Our results showed that the lipid and triacylglycerol content were increased under N starvation conditions. Thus, a two-phase strategy with an initial nutrient-sufficient reactor followed by a nutrient deprivation strategy could likely balance the desire for rapid and high biomass generation (124 mg/L) with a high oil content (50%) of Chlorella minutissima to maximize the total amount of oil produced for biodiesel production. Moreover, methyl palmitate (C16:0), methyl oleate (C18:1), methyl linoleate (C18:2), and methyl linolenate (C18:3) are the major components of Chlorella minutissima derived FAME, and choice of light source, intensity, and N starvation impacted the FAME composition of Chlorella minutissima. The optimized cultivation conditions resulted in higher growth rate, cell density, and oil content, making Chlorella minutissima a potentially suitable organism for biodiesel feedstock production. PMID:21495011

  4. Clocks in algae.

    PubMed

    Noordally, Zeenat B; Millar, Andrew J

    2015-01-20

    As major contributors to global oxygen levels and producers of fatty acids, carotenoids, sterols, and phycocolloids, algae have significant ecological and commercial roles. Early algal models have contributed much to our understanding of circadian clocks at physiological and biochemical levels. The genetic and molecular approaches that identified clock components in other taxa have not been as widely applied to algae. We review results from seven species: the chlorophytes Chlamydomonas reinhardtii, Ostreococcus tauri, and Acetabularia spp.; the dinoflagellates Lingulodinium polyedrum and Symbiodinium spp.; the euglenozoa Euglena gracilis; and the red alga Cyanidioschyzon merolae. The relative simplicity, experimental tractability, and ecological and evolutionary diversity of algal systems may now make them particularly useful in integrating quantitative data from "omic" technologies (e.g., genomics, transcriptomics, metabolomics, and proteomics) with computational and mathematical methods. PMID:25379817

  5. Algae as an electron donor promoting sulfate reduction for the bioremediation of acid rock drainage.

    PubMed

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, Jim A

    2016-11-01

    This study assessed bioremediation of acid rock drainage in simulated permeable reactive barriers (PRB) using algae, Chlorella sorokiniana, as the sole electron donor for sulfate-reducing bacteria. Lipid extracted algae (LEA), the residues of biodiesel production, were compared with whole cell algae (WCA) as an electron donor to promote sulfate-reducing activity. Inoculated columns containing anaerobic granular sludge were fed a synthetic medium containing H2SO4 and Cu(2+). Sulfate, sulfide, Cu(2+) and pH were monitored throughout the experiment of 123d. Cu recovered in the column packing at the end of the experiment was evaluated using sequential extraction. Both WCA and LEA promoted 80% of sulfate removal (12.7mg SO4(2-) d(-1)) enabling near complete Cu removal (>99.5%) and alkalinity generation raising the effluent pH to 6.5. No noteworthy sulfate reduction, alkalinity formation and Cu(2+) removal were observed in the endogenous control. In algae amended-columns, Cu(2+) was precipitated with biogenic H2S produced by sulfate reduction. Formation of CuS was evidenced by sequential extraction and X-ray diffraction. LEA and WCA provided similar levels of electron donor based on the COD balance. The results demonstrate an innovative passive remediation system using residual algae biomass from the biodiesel industry. PMID:27318730

  6. Purification, characterization and cDNA cloning of soluble carbonic anhydrase from Chlorella sorokiniana grown under ordinary air.

    PubMed

    Satoh, A; Iwasaki, T; Odani, S; Shiraiwa, Y

    1998-11-01

    Soluble carbonic anhydrase (CA, EC 4.2.1.1) inducible by low levels of CO2 was purified from the unicellular green alga Chlorella sorokiniana grown at alkaline pH. The purified CA had a specific activity of 2,300 units (mg protein)-1. The molecular mass of the CA was found to be 100 kDa by non-dissociating (native)-polyacrylamide gel electrophoresis and 50 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The 50-kDa subunit was recognized by concanavalin A. These results suggest that the protein has a dimeric form with two 50-kDa subunits that are glycosylated in an asparagine-linked manner. The native CA was revealed by isoelectric focusing to be a very acidic protein with an isoelectric point of 4.2. About 60% of the CA activity was inhibited by 0.5 M NaCl. The enzyme was inactivated over 95% by preincubation with 50 mM dithiothreitol but not with 1 mM dithiothreitol. After partial amino acid sequence analysis, a cDNA clone of the CA was isolated and characterized. The cloned cDNA fragment encoded a 348-amino-acid polypeptide (36,709 Da) including an NH2-terminal hydrophobic signal peptide composed of 35 amino acids (3,725 Da). Conserved regions of sequences found in animal CAs, in the periplasmic (pCA) and the intracellular CAs of Chlamydomonas, and in the plasma-membrane-bound CA of Dunaliella (Dca) were also found in this Chlorella CA. The signal sequence was significantly homologous to the pCA and the Dca. The internal signal sequence between the large and the small subunits reported for pCA was not found in this Chlorella CA. The soluble CA of this alga was an alpha-type CA with salt-sensitive, periplasm-locating and acidic properties and very different from pCA and Dca with their salt-sensitive/neutral and salt-resistant/acidic properties, respectively. PMID:9821693

  7. Bioregeneration with maltose excreting Chlorella: system concept, technological development, and experiments.

    PubMed

    Wolf, L

    1997-01-01

    ESA has been studying a small-scale bioregenerative system to support long-term biological experiments on-board spacecraft with oxygen, water and food. Core component of this system is a special photo-bioreactor in which a maltose-producing strain of the green micro alga Chlorella is cultivated. A number of auxiliary system components have been developed and are functioning on the ground according to the design specifications, among them a gas/liquid phase separator operating at the same time as a low shear-stress pneumatic pump, a dehumidifier, a maltose separator, and a liquid transfer system. All components have been designed so that--in principle--they will operate in weightlessness, though this has so far only been verified for the gas/liquid separator. The bioreactor and some of the auxiliary components have been integrated in a prototype system, which has been subjected to preliminary testing. The prototype has been sterilized successfully by autoclaving, except for the liquid transfer unit which is disinfected with isopropyl alcohol. Chlorella 241.80 has been cultured several times under controlled conditions for up to 8 weeks. Algal growth to a biomass concentration of 9 g.l-1 dry weight and maltose production to a concentration of 17 g.l-1 have been achieved. The low shear-stress pneumatic pump works reliably without the mechanical cell damage produced by other types of pumps. Contamination of the algal cultures by other micro-organisms has been avoided in most of the experiment runs. The maximum oxygen production rate observed was 2 ml.min-1, when the culture was aerated with air +0.5% CO2. This production rate is well below the CO2 gas transfer rate of 5 ml.min-1 under these conditions. It can probably be doubled by increasing the maximum light intensity of the illumination unit (currently 300 micro E.m-2S-1). In a preliminary closed gas loop experiment with Periplaneta as consumer, the possibility of controlling the Chlorella culture so as to match the

  8. Ozone inhibition of photosynthesis in Chlorella sorokiniana

    SciTech Connect

    Heath, R.L.; Frederick, P.E.; Chimiklis, P.E.

    1982-01-01

    Exposure of Chlorella sorokiniana (07-11-05) to ozone inhibits photosynthesis. In this study, the effects of ozone on O/sub 2/ evolution and fluorescence yields are used to characterize this inhibition. At an ozone dose of about 3 micromoles delivered to 2 x 10/sup 9/ cells, the photosynthetic rate of the cells is inhibited 50%, as indicated by a decrease in bicarbonate-stimulated O/sub 2/ evolution (control rate, 1.4 +- 0.3 x 10/sup -15/ moles per cell per minute). Normal patterns of chlorophyll fluorescence are also altered. Upon continuous exposure to ozone (3.5 x 10/sup -7/ moles O/sub 3/ per minute), three stages of change in relative fluorescence yields are observed: (a) a rise in variable yield with no corresponding change in nonvariable yield (after 1-2 minutes), which was interpreted to be a shift in the energy flow pathway; (b) a decline in variable yield with a slight rise in nonvariable yield (requiring 3-5 minutes), interpreted to be a blockage in the CO/sub 2/ fixation pathways; and (c) complete blockage of variable yield with a concurrent decline in nonvariable yield (8-10 minutes), interpreted to be a destruction of the pigment system. The timing of each stage depended upon the ozone concentration and its delivery rate to the cell suspension. These results are compared with ozone-induced decline in photosynthesis and leaf water potential changes reported for other plant systems. Evidence is also presented to suggest that ozone effects on the photosynthetic processes are attributable to ionic imbalances brought about by ozone interaction with the plasmalemma rather than a direct effect on the chloroplast. 25 references, 6 figures, 2 tables.

  9. 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

  10. 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. PMID:20547326

  11. 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. PMID:25266686

  12. Unlocking nature's treasure-chest: screening for oleaginous algae.

    PubMed

    Slocombe, Stephen P; Zhang, QianYi; Ross, Michael; Anderson, Avril; Thomas, Naomi J; Lapresa, Ángela; Rad-Menéndez, Cecilia; Campbell, Christine N; Black, Kenneth D; Stanley, Michele S; Day, John G

    2015-01-01

    Micro-algae synthesize high levels of lipids, carbohydrates and proteins photoautotrophically, thus attracting considerable interest for the biotechnological production of fuels, environmental remediation, functional foods and nutraceuticals. Currently, only a few micro-algae species are grown commercially at large-scale, primarily for "health-foods" and pigments. For a range of potential products (fuel to pharma), high lipid productivity strains are required to mitigate the economic costs of mass culture. Here we present a screen concentrating on marine micro-algal strains, which if suitable for scale-up would minimise competition with agriculture for water. Mass-Spectrophotometric analysis (MS) of nitrogen (N) and carbon (C) was subsequently validated by measurement of total fatty acids (TFA) by Gas-Chromatography (GC). This identified a rapid and accurate screening strategy based on elemental analysis. The screen identified Nannochloropsis oceanica CCAP 849/10 and a marine isolate of Chlorella vulgaris CCAP 211/21A as the best lipid producers. Analysis of C, N, protein, carbohydrate and Fatty Acid (FA) composition identified a suite of strains for further biotechnological applications e.g. Dunaliella polymorpha CCAP 19/14, significantly the most productive for carbohydrates, and Cyclotella cryptica CCAP 1070/2, with utility for EPA production and N-assimilation. PMID:26202369

  13. 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

  14. Ecotoxicological effects of carbon nanotubes and cellulose nanofibers in Chlorella vulgaris

    PubMed Central

    2014-01-01

    Background MWCNT and CNF are interesting NPs that possess great potential for applications in various fields such as water treatment, reinforcement materials and medical devices. However, the rapid dissemination of NPs can impact the environment and in the human health. Thus, the aim of this study was to evaluate the MWCNT and cotton CNF toxicological effects on freshwater green microalgae Chlorella vulgaris. Results Exposure to MWCNT and cotton CNF led to reductions on algal growth and cell viability. NP exposure induced reactive oxygen species (ROS) production and a decreased of intracellular ATP levels. Addition of NPs further induced ultrastructural cell damage. MWCNTs penetrate the cell membrane and individual MWCNTs are seen in the cytoplasm while no evidence of cotton CNFs was found inside the cells. Cellular uptake of MWCNT was observed in algae cells cultured in BB medium, but cells cultured in Seine river water did not internalize MWCNTs. Conclusions Under the conditions tested, such results confirmed that exposure to MWCNTs and to cotton CNFs affects cell viability and algal growth. PMID:24750641

  15. 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

  16. Photorespiration participates in the assimilation of acetate in Chlorella sorokiniana under high light.

    PubMed

    Xie, Xiujun; Huang, Aiyou; Gu, Wenhui; Zang, Zhengrong; Pan, Guanghua; Gao, Shan; He, Linwen; Zhang, Baoyu; Niu, Jianfeng; Lin, Apeng; Wang, Guangce

    2016-02-01

    The development of microalgae on an industrial scale largely depends on the economic feasibility of mass production. High light induces productive suspensions during cultivation in a tubular photobioreactor. Herein, we report that high light, which inhibited the growth of Chlorella sorokiniana under autotrophic conditions, enhanced the growth of this alga in the presence of acetate. We compared pigments, proteomics and the metabolic flux ratio in C. sorokiniana cultivated under high light (HL) and under low light (LL) in the presence of acetate. Our results showed that high light induced the synthesis of xanthophyll and suppressed the synthesis of chlorophylls. Acetate in the medium was exhausted much more rapidly in HL than in LL. The data obtained from LC-MS/MS indicated that high light enhanced photorespiration, the Calvin cycle and the glyoxylate cycle of mixotrophic C. sorokiniana. The results of metabolic flux ratio analysis showed that the majority of the assimilated carbon derived from supplemented acetate, and photorespiratory glyoxylate could enter the glyoxylate cycle. Based on these data, we conclude that photorespiration provides glyoxylate to speed up the glyoxylate cycle, and releases acetate-derived CO2 for the Calvin cycle. Thus, photorespiration connects the glyoxylate cycle and the Calvin cycle, and participates in the assimilation of supplemented acetate in C. sorokiniana under high light. PMID:26439434

  17. 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.

  18. Chlorella pyrenoidosa cultivation in outdoors using the diluted anaerobically digested activated sludge.

    PubMed

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

    2015-12-01

    A freshwater green algae Chlorella pyrenoidosa (C. pyrenoidosa) was cultured in outdoors using the diluted anaerobically digested activated sludge (ADAS). The outdoors batch culture in every season showed that C. pyrenoidosa can grow normally under natural conditions in the diluted ADAS (STE/ADAS=1.5/1, 3/1 and 5/1, v/v). Seasonal changes of environmental conditions significantly affected biomass growth and nutrient removal. Optimal biomass growth and nutrient removal was achieved at STE/ADAS=1.5/1 during summer culture, harvesting a maximum biomass concentration of 1.97 ± 0.21 g/L, average biomass productivity of 291.52 ± 33.74 g/m(3)/day (maximum value of 573.10 ± 41.82) and average lipids productivity of 37.49 ± 5.26 g/m(3)/day (maximum value of 73.70 ± 9.75); simultaneously, the microalgae growth effectively removed nutrients from the wastewater, including 105.6 ± 17.1 mg CODCr/L/day, 36.8 ± 6.1mg N/L/day and 6.1 ± 1.1 mg P/L/day. PMID:26407348

  19. 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. PMID:25782619

  20. Effect of nonylphenol on response of physiology and photosynthesis-related gene transcription of Chlorella vulgaris.

    PubMed

    Qian, Haifeng; Pan, Xiangjie; Shi, Shutian; Yu, Shuqiong; Jiang, Haiyan; Lin, Zhifan; Fu, Zhengwei

    2011-11-01

    Nonylphenol (NP) is regarded as a kind of persistent organic pollutant which exists ubiquitously in the environment. The objective of this study was to evaluate the effects of NP on Chlorella vulgaris physiological indices and gene transcription. The results showed that NP stress inhibited algal growth in short-term bioassay. NP also decreased chlorophyll content, including chl a, chl b, and total chlorophyll. NP caused oxidant hurt by overproducing reactive oxygen species (ROS), which might destroy the overall membrane system to cause malondialdehyde content increase. NP inhibited photosynthesis-related gene transcription in C. vulgaris after 24 to 48 h exposure. The lowest transcript levels of psaB, psbA, and rbcL in C. vulgaris decreased to only 18.5%, 7%, and 4% of the control, respectively. Taken together, our results demonstrate that NP is toxic to fresh algae growth by affecting the photosynthesis-related genes transcription and overproducing ROS to disrupt cell structure in a short period. PMID:21207133

  1. SOME FACTORS IN THE COMPETITION OR ANTAGONISM AMONG BACTERIA, ALGAE, AND AQUATIC WEEDS.

    PubMed

    Filzgerald, G P

    1969-12-01

    Field observations of changes in the populations of aquatic weeds and phytoplankton have confirmed that aquatic weeds have antagonistic activity toward phytoplankton. Nutritional studies in the laboratory indicate that cultures of the aquatic weeds, Myriophyllum sp., Ceratophyllum sp., and duckweed (Lemma minor L.); liquid cultures of barley (Hordeum vulgare L., Dickson variety); and cultures of the filamentous green algae, Cladophora sp. and Pithophora oedogonium (Mont.) Withrock, will remain relatively free of epiphytes or competing phytoplankton if the cultures are nitrogen-limited. Field observations of Cladophora sp. have confirmed that the growth of epiphytes on the Cladophora is related to conditions of surplus available nitrogen compounds. It is proposed that this antagonistic activity may be due to a "nitrogen sink" effect in which the aquatic weeds or filamentous green algae prevent the growth of contaminating algae by competition for the limited nitrogen compounds available. However, the presence of bacteria-sized organisms which have selective toxicity to certain algae indicates that perhaps multiple factors exist. Discussed are the ecological implications of associations of certain algae with bacteria that have selective toxicities for other species of algae under certain environmental conditions such as nitrogen-limited growth. PMID:27096454

  2. Chlorella vulgaris: A Multifunctional Dietary Supplement with Diverse Medicinal Properties.

    PubMed

    Panahi, Yunes; Darvishi, Behrad; Jowzi, Narges; Beiraghdar, Fatemeh; Sahebkar, Amirhossein

    2016-01-01

    Chlorella vulgaris is a green unicellular microalgae with biological and pharmacological properties important for human health. C. vulgaris has a long history of use as a food source and contains a unique and diverse composition of functional macro- and micro-nutrients including proteinsChlorella vulgaris is a green unicellular microalgae with biological and pharmacological properties important for human health. C. vulgaris has a long history of use as a food source and contains a unique and diverse composition of functional macro- and micro-nutrients including proteins, omega-3 polyunsaturated fatty acids, polysaccharides, vitamins and minerals. Clinical trials have suggested that supplementation with C. vulgaris can ameliorate amelioration hyperlipidemia and hyperglycemia, and protect against oxidative stress, cancer and chronic obstructive pulmonary disease. In this review, we summarize the findings on the health benefits of Chlorella supplementation and the molecular mechanisms underlying these effects., omega-3 polyunsaturated fatty acids, polysaccharides, vitamins and minerals. Clinical trials have suggested that supplementation with C. vulgaris can ameliorate amelioration hyperlipidemia and hyperglycemia, and protect against oxidative stress, cancer and chronic obstructive pulmonary disease. In this review, we summarize the findings on the health benefits of Chlorella supplementation and the molecular mechanisms underlying these effects. PMID:26561078

  3. Functional expression of the Chlorella hexose transporter in Schizosaccharomyces pombe.

    PubMed Central

    Sauer, N; Caspari, T; Klebl, F; Tanner, W

    1990-01-01

    Schizosaccharomyces pombe cells were transformed with an S. pombe expression vector containing a full-length cDNA of the Chlorella hexose transporter. The transformed cells accumulated 3-O-methylglucose up to 10-fold, whereas wild-type S. pombe and control transformants could only equilibrate this sugar analogue. In a pH-jump experiment, in which extracellular pH was lowered by 1.9 units, the accumulation ratio was increased in transformed cells but not in control cells. This result indicates that the gene product, Chlorella H+/glucose-symporter protein, and a pH gradient suffice for active sugar uptake. Km values for glucose, 6-deoxyglucose, and 3-O-methylglucose of 1.5 x 10(-5) M, 2.7 x 10(-4) M, and 1.0 x 10(-3) M, respectively, were identical in Chlorella and in S. pombe cells transformed with Chlorella cDNA and approximately 100-fold lower than those of the endogenous transport system of S. pombe. Images PMID:11607110

  4. 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.

  5. 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

  6. The role of vanadium in gree plants. II. Vanadium in green algae--two sites of action.

    PubMed

    Meisch, H U; Benzschawel, H; Bielig, H J

    1977-07-26

    Cells of Chlorella pyrenoidosa, derived from vanadium free agar slants, respond with great sensitivity to microamounts of vanadium, added as NH4VO3 to autotrophic liquid cultures. Between 0.01 and 1 microgram V per litre nutrient medium (2-10(-10)-2-10(-8) g-at/1), the algae respond with a continuous incrase in dry weight. At higher V-concentrations, further enhancement in biomass is accompanied by a additional increase in chlorophyll content. Maximum V-effect on both parameters was found to be at 500 microgram V/1 (10(-5) G-AT/1). Dry weight as well as chlorophyll content of Chlorella are decreased by concentrations above 25 mg V/1; 100 mg V/1 (2-10(-3) g-at/1) stop growth and cause death of the cells. The toxic threshold for the V-content in the algae was determined to be at 150-200 microgram V/g (3-4-10(-6) g-at/g) dry weight. Two different pH-optima for a positive vanadium action on dry weight and chlorophyll biosynthesis were established, the first at pH 7, the other in the range pH 7.5--8. Two sites of vanadium action in green algae are discussed. PMID:20864

  7. Catalytic hydrothermal gasification of algae for hydrogen production: composition of reaction products and potential for nutrient recycling.

    PubMed

    Onwudili, Jude A; Lea-Langton, Amanda R; Ross, Andrew B; Williams, Paul T

    2013-01-01

    Chlorella vulgaris, Spirulina platensis and Saccharina latissima were processed under supercritical water gasification conditions at 500 °C, 36 MPa in an Inconel batch reactor for 30 min in the presence/absence of NaOH and/or Ni-Al(2)O(3). Hydrogen gas yields were more than two times higher in the presence of NaOH than in its absence and tar yields were reduced by up to 71%. Saccharina, a carbohydrate-rich macro-alga, gave the highest hydrogen gas yields of 15.1 mol/kg. The tars from all three algae contained aromatic compounds, including phenols, alkyl benzenes and polycyclic aromatic hydrocarbons as well as heterocyclic nitrogen compounds. Tars from Chlorella and Spirulina contained high yields of pyridines, pyrroles, indoles and pyrimidines. Up to 97% TOC removal were achieved in the process waters from the gasification of the algae. Analyses for specific nutrients in the process waters indicated that the process waters from Saccharina could potentially be used for microalgae cultivation. PMID:23131625

  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. 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

  10. 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

  11. 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. PMID:26440759

  12. 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.

  13. Effect of lycopene from Chlorella marina on high cholesterol-induced oxidative damage and inflammation in rats.

    PubMed

    Renju, G L; Kurup, G Muraleedhara; Saritha Kumari, C H

    2014-02-01

    Even though the role of all-trans lycopene from tomato in controlling atherosclerosis was reported, but no report is available on the cis-isomer of lycopene obtained from an easily available source green algae Chlorella marina. So in this study, Sprague Dawley rats fed with high-cholesterol diet were given standard drug lovastatin; algal lycopene (AL) (cis/all-trans 40:60) and tomato all-trans lycopene (TL) and the following parameters were studied. Total cholesterol, low-density lipoprotein, triglycerides were decreased significantly and the high-density lipoprotein levels were increased on treatment with AL. The activities of antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase were found to be increased, whereas thiobarbituric acid reactive substances levels were decreased in AL when compared to the drug and TL-treated rats. The activities of inflammatory marker enzymes like cyclooxygenase, 15-lipoxygenase in monocytes and myeloperoxidase, C-reactive protein and ceruloplasmin levels in serum were found to be decreased on treatment with AL. Histopathological studies revealed that lycopene from this alga could reduce fatty liver and aortic plaque when compared to the drug and TL. Algal lycopene showed very significant antioxidant and anti-inflammatory effect in high-cholesterol fed rats. Therefore, AL from C. marina would be recommended for the treatment of hyperlipidemia. PMID:23887896

  14. Arsoniumphospholipid in algae*

    PubMed Central

    Cooney, Robert V.; Mumma, R. O.; Benson, A. A.

    1978-01-01

    A novel phospholipid containing arsenic was formed by all marine algae cultured in [74As]arsenate. Components of the labeled algal extracts readily separated by two-dimensional paper radiochromatography. Base-catalyzed deacylation of the major lipid yielded a phosphodiester identical to one of the two major water-soluble compounds. Acid or enzymic hydrolysis of the phosphodiester produced a product identified as trimethylarsoniumalactic acid. The structure of the phospholipid therefore is O-phosphatidyltrimethylarsoniumlactic acid. Detoxication of arsenate by marine algae leads to accumulation of the arsoniumphospholipid as a major reservoir for arsenic. Its degradation to trimethylarsoniumbetaine, dimethylarsinic acid, methanearsonic acid, and arsenate in marine food chains and its metabolism in human beings are of considerable interest. Images PMID:16592562

  15. Genomics of Volvocine Algae

    PubMed Central

    Umen, James G.; Olson, Bradley J.S.C.

    2015-01-01

    Volvocine algae are a group of chlorophytes that together comprise a unique model for evolutionary and developmental biology. The species Chlamydomonas reinhardtii and Volvox carteri represent extremes in morphological diversity within the Volvocine clade. Chlamydomonas is unicellular and reflects the ancestral state of the group, while Volvox is multicellular and has evolved numerous innovations including germ-soma differentiation, sexual dimorphism, and complex morphogenetic patterning. The Chlamydomonas genome sequence has shed light on several areas of eukaryotic cell biology, metabolism and evolution, while the Volvox genome sequence has enabled a comparison with Chlamydomonas that reveals some of the underlying changes that enabled its transition to multicellularity, but also underscores the subtlety of this transition. Many of the tools and resources are in place to further develop Volvocine algae as a model for evolutionary genomics. PMID:25883411

  16. The optimal hyperspectral quantitative models for chlorophyll-a of chlorella vulgaris

    NASA Astrophysics Data System (ADS)

    Cheng, Qian; Wu, Xiuju

    2009-09-01

    Chlorophyll-a of Chlorella vulgaris had been related with spectrum. Based on hyperspectral measurement for Chlorella vulgaris, the hyperspectral characteristics of Chlorella vulgaris and their optimal hyperspectral quantitative models of chlorophyll-a (Chla) estimation were researched in situ experiment. The results showed that the optimal hyperspectral quantitative model of Chlorella vulgaris was Chla=180.5+1125787(R700)'+2.4 *109[(R700)']2 (P0<.01), and the suitability order of corresponding methods was spectral ratioChlorella vulgaris, two reflectance crests were around 540 nm and 700 nm and their locations moved right while Chl-a concentration increased. The reflectance of Chlorella vulgaris decreases with Cha concentration increase in 540 nm, but on the contrary in 700nm.

  17. Study of Selecting on Light Source Used for Micro-algae Cultivation in Space

    NASA Astrophysics Data System (ADS)

    Ai, Weidang; Ai, Weidang; Guo, Shuang-Sheng; Gao, Feng; Tang, Yong-Kang; Qin, Li-Feng

    To select suitable light source for micro-algae cultivation in future space station, the selected Spirulina plastensis(No.7) were cultured under different lightening qualities, including six light sources that were made up of different combinations of red and blue light-emitting diode(LED). The growth, photosynthetic efficiency and nutrition quality of the Spirulina, were analyzed. From the experiments, the red light may promote the cumulation of biomass of the Spirulina, and the cumulating rate was the highest under all red light source, but the syntheses of protein, phycobiliprotein, β-carotene, VE and other nutrients needs a certain portion of blue light; yet, the complete blue light condition is not favorable to the growth of Spirulina, and may bring pollution by chlorella and other kinds of micro-algae. It is concluded that the LEDs can be used as the light resource of micro-algae cultivation. The normal growth and development of microalgae need two light sources of both red and blue LEDs. The comprehensive analyses of the various factors that affect the growth of Spirulina, such as nutrition quality and photosynthetic activities, etc., showed that the combination of 80% red and 20% blue LED is the optimum one among those tested combinations. Key word: light-emitting diode; micro-algae; controlled ecological life support system (CELSS); space cultivation

  18. Antioxidant properties of a new antioxidative peptide from algae protein waste hydrolysate in different oxidation systems.

    PubMed

    Sheih, I-Chuan; Wu, Tung-Kung; Fang, Tony J

    2009-07-01

    Microalgae have been a popular edible food, but there are no known reports on the antioxidative peptides derived from microalgae. The algae protein waste, which is normally discarded as animal feed, is a by-product during production of algae essence from microalgae, Chlorella vulgaris. Algae protein waste was hydrolyzed using pepsin, and a potent antioxidative peptide of VECYGPNRPQF was separated and isolated. The peptide could efficiently quench a variety of free radicals, including hydroxyl radical, superoxide radical, peroxyl radical, DPPH radical and ABTS radicals, and performed more efficiently than that observed for BHT, Trolox and peptides from marine protein sources in most cases. The purified peptide also has significant protective effects on DNA and prevents cellular damage caused by hydroxyl radicals. In addition, the peptide has gastrointestinal enzyme-resistance and no cytotoxicity observed in human lung fibroblasts cell lines (WI-38) in vitro. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce antioxidative peptides. PMID:19299123

  19. The adsorption potential and recovery of thallium using green micro-algae from eutrophic water sources.

    PubMed

    Birungi, Z S; Chirwa, E M N

    2015-12-15

    Thallium (Tl) is a highly volatile and toxic heavy metal regarded to cause pollution even at very low concentrations of several parts per million. Despite the extremely high risk of Tl in the environment, limited information on removal/recovery exists. The study focussed on the use of green algae to determine the sorption potential and recovery of Tl. From the study, removal efficiency was achieved at 100% for lower concentrations of ≥150 mg/L of Tl. At higher concentrations in a range of 250-500 mg/L, the performance of algae was still higher with sorption capacity (qmax) between 830 and 1000 mg/g. Generally, Chlorella vulgaris was the best adsorbent with a high qmax and lower affinity of 1000 mg/g and 1.11 L/g, respectively. When compared to other studies on Tl adsorption, the tested algae showed a better qmax than most adsorbents. The kinetic studies showed better correlation co-efficient of ≤0.99 for Pseudo-second order model than the first order model. Recovery was achieved highest for C. vulgaris using nitric acid at 93.3%. The strongest functional groups responsible for Tl binding on the algal cell wall were carboxyl and phenols. Green algae from freshwater bodies showed significant potential for Tl removal/recovery from industrial wastewater. PMID:26093356

  20. The effect of natural organic matter on bioaccumulation and toxicity of chlorobenzenes to green algae.

    PubMed

    Zhang, Shuai; Lin, Daohui; Wu, Fengchang

    2016-07-01

    The effect of natural organic matter (NOM) on toxicity and bioavailability of hydrophobic organic contaminants (HOCs) to aquatic organisms has been investigated with conflicting results and undefined mechanisms, and few studies have been conducted on volatile HOCs. In this study, six volatile chlorobenzenes (CBs) with 1-6 chlorine substitutions were investigated for their bioaccumulation in an acute toxicity to a green alga (Chlorella pyrenoidosa) in the presence/absence of Suwannee River NOM (SRNOM). The fluorescence quenching efficiency of SRNOM increased as the number of chlorine substitutions of CBs increased. SRNOM increased the cell-surface hydrophobicity of algae and decreased the release rates of algae-accumulated CBs, thus increasing the concentration factor (CF) and accumulation of the CBs in the algae. SRNOM increased the toxicity of monochlorobenzene and 1,2-dichlorobenzene, decreased the toxicity of pentachlorobenzene and hexachlorobenzene, and had no significant effect on the toxicity of 1,2,3-trichlorobenzene and 1,2,3,4-tetrachlorobenzene. Relationships between the 96h CF/IC50 (i.e., the CB concentration leading to a 50% algal growth reduction compared with the control) and physicochemical properties of CBs with/without SRNOM were established, providing reasonable explanations for the experimental results. These findings will help with the accurate assessment of ecological risks of organic pollutants in the presence of NOM. PMID:26989981

  1. Influence of extractive solvents on lipid and fatty acids content of edible freshwater algal and seaweed products, the green Microalga Chlorella kessleri and the Cyanobacterium Spirulina platensis.

    PubMed

    Ambrozova, Jarmila Vavra; Misurcova, Ladislava; Vicha, Robert; Machu, Ludmila; Samek, Dusan; Baron, Mojmir; Mlcek, Jiri; Sochor, Jiri; Jurikova, Tunde

    2014-01-01

    Total lipid contents of green (Chlorella pyrenoidosa, C), red (Porphyra tenera, N; Palmaria palmata, D), and brown (Laminaria japonica, K; Eisenia bicyclis, A; Undaria pinnatifida, W, WI; Hizikia fusiformis, H) commercial edible algal and cyanobacterial (Spirulina platensis, S) products, and autotrophically cultivated samples of the green microalga Chlorella kessleri (CK) and the cyanobacterium Spirulina platensis (SP) were determined using a solvent mixture of methanol/chloroform/water (1:2:1, v/v/v, solvent I) and n-hexane (solvent II). Total lipid contents ranged from 0.64% (II) to 18.02% (I) by dry weight and the highest total lipid content was observed in the autotrophically cultivated cyanobacterium Spirulina platensis. Solvent mixture I was found to be more effective than solvent II. Fatty acids were determined by gas chromatography of their methyl esters (% of total FAMEs). Generally, the predominant fatty acids (all results for extractions with solvent mixture I) were saturated palmitic acid (C16:0; 24.64%-65.49%), monounsaturated oleic acid (C18:1(n-9); 2.79%-26.45%), polyunsaturated linoleic acid (C18:2(n-6); 0.71%-36.38%), α-linolenic acid (C18:3(n-3); 0.00%-21.29%), γ-linolenic acid (C18:3(n-6); 1.94%-17.36%), and arachidonic acid (C20:4(n-6); 0.00%-15.37%). The highest content of ω-3 fatty acids (21.29%) was determined in Chlorella pyrenoidosa using solvent I, while conversely, the highest content of ω-6 fatty acids (41.42%) was observed in Chlorella kessleri using the same solvent. PMID:24566307

  2. Comparative study of the trophic transfer of two mercury compounds--HgCl/sub 2/ and CH/sub 3/HgCl--between Chlorella vulgaris and Daphnia magna. Influence of temperature

    SciTech Connect

    Baudou, A.; Ribeyre, F.

    1981-12-01

    A comparative study is presented of the transfer of HgCl/sub 2/ and CH/sub 3/HgCl between a species representative of the ''producer'' level -- Chlorella vulgaris -- and a primary consumer -- Daphnia magna. The experiment was carried out at two temperatures, 10 and 18/sup 0/C, and the concentration of metal in the environment was 1 ..mu..g.l/sup -1/ (1 ppb). Results seem to indicate that the two contaminants, which are first introduced into the environment and then fixed by the unicellular algae, retain their specific property of crossing the digestive barrier of the consumer link.

  3. Effect of sonication frequency on the disruption of algae.

    PubMed

    Kurokawa, Masaki; King, Patrick M; Wu, Xiaoge; Joyce, Eadaoin M; Mason, Timothy J; Yamamoto, Ken

    2016-07-01

    In this study, the efficiency of ultrasonic disruption of Chaetoceros gracilis, Chaetoceros calcitrans, and Nannochloropsis sp. was investigated by applying ultrasonic waves of 0.02, 0.4, 1.0, 2.2, 3.3, and 4.3 MHz to algal suspensions. The results showed that reduction in the number of algae was frequency dependent and that the highest efficiency was achieved at 2.2, 3.3, and 4.3MHz for C. gracilis, C. calcitrans, and Nannochloropsis sp., respectively. A review of the literature suggested that cavitation, rather than direct effects of ultrasonication, are required for ultrasonic algae disruption, and that chemical effects are likely not the main mechanism for algal cell disruption. The mechanical resonance frequencies estimated by a shell model, taking into account elastic properties, demonstrated that suitable disruption frequencies for each alga were associated with the cell's mechanical properties. Taken together, we consider here that physical effects of ultrasonication were responsible for algae disruption. PMID:26964936

  4. Settlement of marine periphytic algae in a tropical estuary

    NASA Astrophysics Data System (ADS)

    Nayar, S.; Goh, B. P. L.; Chou, L. M.

    2005-08-01

    This note describes settlement studies of marine periphytic algae on glass substrata in a tropical estuary in Singapore. The rates of production in terms of 14C radiotracer uptake, biomass in terms of chlorophyll a, community structure and cell abundance were measured from the settled periphytic algae at various depths in the water column and compared with the prevailing hydrographical conditions. Relatively higher periphytic algal settlement was observed at 1 m depth, even though it was not statistically different from other depths. Diatoms such as Skeletonema costatum and Thalassiosira rotula dominated the assemblage, together with the marine cyanobacteria Synechococcus sp. The three settlement parameters viz., periphytic algal production, chlorophyll a and cell counts showed significant differences between the days of settlement, with no significant differences observed for different depths. The periphytic algal community in this study comprised 30 microalgal species, dominated by diatoms (78%), followed by cyanobacteria (19% - primarily Synechococcus sp.), green flagellates (1%), dinoflagellates (1%) and other forms accounting for the remaining 1% of the total cell counts. Correlation studies and principal component analysis (PCA) revealed significant influence of silicate concentrations in the water column with the settlement of periphytic algae in this estuary. Though photoinhibited at the surface, photosynthetically available radiation did not seem to influence the overall settlement of periphytic algae. Diatoms and Synechococcus in the periphytic algal community were influenced by water temperature, PAR, pH and dissolved oxygen as seen in the PCA plots.

  5. Viruses of eukaryotice green algae

    SciTech Connect

    Van Etten, J.L.

    1989-01-01

    The primary objective of our research was to develop the Chlorella-PBCV-1 virus system so that it can be used as a model system for studying gene expression in a photosynthetic eukaryote. We have made considerable progress and have learned much about PBCV-1 and its replication cycle. In addition, several significant discoveries were made in the last 3 to 4 years. These discoveries include: (i) the finding that morphologically similar, plaque forming, dsDNA containing viruses are common in nature and can be isolated readily from fresh water, (ii) the finding that all of these Chlorella viruses contain methylated bases which range in concentration from 0.1% to 47.5% m{sup 5}dC and 0 to 37% m{sup 6}dA and (iii) the discovery that infection with at least some of these viruses induces the appearance of DNA modification/restriction systems. 26 refs.

  6. Heme inhibition of [delta]-aminolevulinic acid synthesis is enhanced by glutathione in cell-free extracts of Chlorella

    SciTech Connect

    Weinstein, J.D.; Howell, R.W.; Grooms, S.Y.; Brignola, P.S. ); Mayer, S.M.; Beale, S.I. )

    1993-02-01

    In plants, algae, and many bacteria, the heme and chlorophyll precursor, [delta]-aminolevulinic acid (ALA), is synthesized from glutamate in a reaction involving a glutamyl-tRNA intermediate and requiring ATP and NADAPH as cofactors. In particulate-free extracts of algae and chloroplasts, ALA synthesis is inhibited by heme. Inclusion of 1.0 mM glutathione (GSH) in an enzyme and tRNA extract, derived from the green alga Chlorella vulgaris, lowered the concentration of heme required for 50% inhibition approximately 10-fold. The effect of GSH could not be duplicated with other reduced sulfhydryl compounds, including mercaptoethanol, dithiothreitol, and cysteine, or with imidazole or bovine serum albumin, which bind to heme and dissociate heme dimers. Absorption spectroscopy indicated that heme was fully reduced in incubation medium containing dithiothreitol, and addition of GSH did not alter the heme reduction state. Oxidized GSH was as effective in enhancing heme inhibition as the reduced form. Co-protoporphyrin IX inhibited ALA synthesis nearly as effectively as heme, and 1.0 mM GSH lowered the concentration required for 50% inhibition approximately 10-fold. Because GSH did not influence the reduction state of heme in the incubation medium, and because GSH could not be replaced by other reduced sulfhydryl compounds or ascorbate, the effect of GSH cannot be explained by action as a sulfhydryl protectant or heme reductant. Preincubation of enzyme extract with GSH, followed by rapid gel filtration, could not substitute for inclusion of GSH with heme during the reaction. The results suggest that GSH with heme during the reaction. The results suggest that GSH must specifically interact with the enzyme extract in the presence of the inhibitor to enhance the inhibition. 48 refs., 7 figs., 4 tabs.

  7. Photosynthetic responses and accumulation of mesotrione in two freshwater algae.

    PubMed

    Ni, Yan; Lai, Jinhu; Wan, Jinbao; Chen, Lianshui

    2014-01-01

    Mesotrione is a herbicide used for killing annual grasses and broad-leaved weeds in maize. A recent investigation has shown that mesotrione has been detected as an organic contaminant in aquatic environments and may have a negative impact on aquatic organisms. To evaluate the eco-toxicity of mesotrione to algae, experiments focusing on photosynthetic responses and mesotrione accumulation in Microcystis sp. and Scenedesmus quadricauda were carried out. Both algae treated with mesotrione at 0.05-10 mg L(-1) for 7 days reduced the photosynthetic capacity. The fluorescence of chlorophyll a, the maximal PSII activity (Fv/Fm), and the parameters (Ik, α and ETRmax) of rapid light curves (RLCs) in both algae were decreased under mesotrione exposure. The 96 h EC50 values for mesotrione on S. quadricauda and Microcystis sp. were 4.41 and 6.19 mg L(-1), respectively. The latter shows more tolerance to mesotrione. Mesotrione was shown to be readily accumulated by both species. Such uptake of mesotrione led to the rapid removal of mesotrione from the medium. Overall, this study represents the initial comprehensive analyses of Microcystis sp. and S. quadricauda in adaptation to the mesotrione contaminated aquatic ecosystems. PMID:25059419

  8. Growth of Chlorella sorokiniana at hyperbaric oxygen pressures.

    PubMed

    Richardson, B; Wagner, F W; Welch, B E

    1969-01-01

    The growth rate of Chlorella sorokiniana decreased in a linear fashion as the partial pressure of oxygen was increased from 711 to 1,478 mm of Hg. Under two atmospheres of oxygen pressure, growth ceased after 10 to 12 hr. This cessation of growth was not due to any permanent injury, as growth resumed when oxygen partial pressure was reduced to ambient levels. The inhibition occurred under both autotrophic and heterotrophic growth conditions and was not accompanied by an increase in cell size. The results indicated that the tolerance of Chlorella cells to elevated oxygen pressures was not an absolute immunity, and that inhibition of growth at very high oxygen pressures cannot be accounted for by an inhibition of photosynthesis alone. PMID:5774753

  9. Xenobiotic biotransformation in unicellular green algae. Involvement of cytochrome P450 in the activation and selectivity of the pyridazinone pro-herbicide metflurazon.

    PubMed Central

    Thies, F; Backhaus, T; Bossmann, B; Grimme, L H

    1996-01-01

    The N-demethylation of the pyridazinone pro-herbicide metflurazon into norflurazon implies a toxification in photosynthetic organisms. This is confirmed by quantitative structure activity relationships determined for two unicellular green algae, Chlorella sorokiniana and Chlorella fusca; however, the latter is 25 to 80 times more sensitive to metflurazon. This sensitivity is linked to differences in the N-demethylase activity of both algae, as determined by an optimized in vivo biotransformation assay. Apparent K(m) values of the metflurazon-N-demethylase indicate a 10-fold higher affinity for this xenobiotic substrate for Chlorella fusca. Furthermore, algal metflurazon-N-demethylation is characterized by distinct variations in activity, depending on the stage of cell development within the cell cycle. Several well-established inhibitors of cytochrome P450-mediated reactions, including piperonylbutoxide, 1-aminobenzotriazole, 1-phenoxy-3-(1H-1,2,4-triol-1yl)-4-hydroxy-5,5-dimethylhexane++ +, and tetcyclacis, as well as cinnamic acid, a potential endogenous substrate, inhibited the N-demethylation of metflurazon. The results suggest that the N-demethylation of metflurazon by both algae is mediated by a cytochrome P450 monooxygenase. The determination of antigenic cross-reactivity of algal proteins with heterologous polyclonal antibodies originally raised against plant P450s, anti-cinnamic acid 4-hydroxylase (CYP73A1), anti-ethoxycoumarin-O-dealkylase, anti-tulip allene oxidase (CYP74), and an avocado P450 (CYP71A1) or those of bacterial origin, CYP105A1 and CYP105B1, suggests the presence of distinct P450 isoforms in both algae. PMID:8819332

  10. 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. PMID:26724554

  11. Gas Exchange of Algae

    PubMed Central

    Ammann, Elizabeth C. B.; Lynch, Victoria H.

    1966-01-01

    Changes in the oxygen partial pressure of air over the range of 8 to 258 mm of Hg did not adversely affect the photosynthetic capacity of Chlorella pyrenoidosa. Gas exchange and growth measurements remained constant for 3-week periods and were similar to air controls (oxygen pressure of 160 mm of Hg). Oxygen partial pressures of 532 and 745 mm of Hg had an adverse effect on algal metabolism. Carbon dioxide consumption was 24% lower in the gas mixture containing oxygen at a pressure 532 mm of Hg than in the air control, and the growth rate was slightly reduced. Oxygen at a partial pressure of 745 mm of Hg decreased the photosynthetic rate 39% and the growth rate 37% over the corresponding rates in air. The lowered metabolic rates remained constant during 14 days of measurements, and the effect was reversible after this time. Substitution of helium or argon for the nitrogen in air had no effect on oxygen production, carbon dioxide consumption, or growth rate for 3-week periods. All measurements were made at a total pressure of 760 mm of Hg, and all gas mixtures were enriched with 2% carbon dioxide. Thus, the physiological functioning and reliability of a photosynthetic gas exchanger should not be adversely affected by: (i) oxygen partial pressures ranging from 8 to 258 mm of Hg; (ii) the use of pure oxygen at reduced total pressure (155 to 258 mm of Hg) unless pressure per se affects photosynthesis, or (iii) the inclusion of helium or argon in the gas environment (up to a partial pressure of 595 mm of Hg). PMID:5927028

  12. 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

  13. Integration of algae cultivation as biodiesel production feedstock with municipal wastewater treatment: strains screening and significance evaluation of environmental factors.

    PubMed

    Li, Yecong; Zhou, Wenguang; Hu, Bing; Min, Min; Chen, Paul; Ruan, Roger R

    2011-12-01

    The objectives of this study are to find the robust strains for the centrate cultivation system and to evaluate the effect of environmental factors including light intensity, light-dark cycle, and exogenous CO2 concentration on biomass accumulation, wastewater nutrient removal and biodiesel production. The results showed that all 14 algae strains from the genus of Chlorella, Haematococcus, Scenedesmus, Chlamydomonas, and Chloroccum were able to grow on centrate. The highest net biomass accumulation (2.01 g/L) was observed with Chlorella kessleri followed by Chlorella protothecoides (1.31 g/L), and both of them were proved to be capable of mixotrophic growth when cultivated on centrate. Environmental factors had significant effect on algal biomass accumulation, wastewater nutrients removal and biodiesel production. Higher light intensity and exogenous CO2 concentration with longer lighting period promote biomass accumulation, biodiesel production, as well as the removal of chemical oxygen demand and nitrogen, while, lower exogenous CO2 concentration promotes phosphorus removal. PMID:21982450

  14. Comparative sensitivity of five species of macrophytes and six species of algae to atrazine, metribuzin, alachlor, and metolachlor

    USGS Publications Warehouse

    Fairchild, J.F.; Ruessler, D.S.; Carlson, A.R.

    1998-01-01

    This study determined the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metolachlor). Toxicity tests consisted of 96-h (duckweed and algae) or 14-d (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic plants than were the acetanilide herbicides (alachlor and metolachlor). Toxicity studies ranked metribuzin > atrazine > alachlor > metolachlor in decreasing order of overall toxicity to aquatic plants. Relative sensitivities of macrophytes to these herbicides decreased in the order of Ceratophyllum > Najas > Elodea > Lemna > Myriophyllum. Relative sensitivities of algae to herbicides decreased in the order of Selenastrum > Chlorella > Chlamydomonas > Microcystis > Scenedesmus > Anabaena. Algae and macrophytes were of similar overall sensitivities to herbicides. Data indicated that Selenastrum, a commonly tested green alga, was generally more sensitive compared to other plant species. Lemna minor, a commonly tested floating vascular plant, was of intermediate sensitivity, and was fivefold less sensitive than Ceratophyllum, which was the most sensitive species tested. The results indicated that no species was consistently most sensitive, and that a suite of aquatic plant test species may be needed to perform accurate risk assessments of herbicides.

  15. The impacts of replacing air bubbles with microspheres for the clarification of algae from low cell-density culture.

    PubMed

    Ometto, Francesco; Pozza, Carlo; Whitton, Rachel; Smyth, Beatrice; Gonzalez Torres, Andrea; Henderson, Rita K; Jarvis, Peter; Jefferson, Bruce; Villa, Raffaella

    2014-04-15

    Dissolved Air Flotation (DAF) is a well-known coagulation-flotation system applied at large scale for microalgae harvesting. Compared to conventional harvesting technologies DAF allows high cell recovery at lower energy demand. By replacing microbubbles with microspheres, the innovative Ballasted Dissolved Air Flotation (BDAF) technique has been reported to achieve the same algae cell removal efficiency, while saving up to 80% of the energy required for the conventional DAF unit. Using three different algae cultures (Scenedesmus obliquus, Chlorella vulgaris and Arthrospira maxima), the present work investigated the practical, economic and environmental advantages of the BDAF system compared to the DAF system. 99% cells separation was achieved with both systems, nevertheless, the BDAF technology allowed up to 95% coagulant reduction depending on the algae species and the pH conditions adopted. In terms of floc structure and strength, the inclusion of microspheres in the algae floc generated a looser aggregate, showing a more compact structure within single cell alga, than large and filamentous cells. Overall, BDAF appeared to be a more reliable and sustainable harvesting system than DAF, as it allowed equal cells recovery reducing energy inputs, coagulant demand and carbon emissions. PMID:24525066

  16. Miocene Coralline algae

    SciTech Connect

    Bosence, D.W.J.

    1988-01-01

    The coralline algae (Order Corallinales) were sedimentologically and ecologically important during the Miocene, a period when they were particularly abundant. The many poorly described and illustrated species and the lack of quantitative data in coralline thalli make specific determinations particularly difficult, but some species are well known and widespread in the Tethyan area. The sedimentologic importance of the Miocene coralline algae is reflected in the abundance of in-situ coralline buildups, rhodoliths, and coralline debris facies at Malta and Spain; similar sequences are known throughout the Tethyan Miocene. In-situ buildups vary from leafy crustose biostromes to walled reefs with dense coralline crusts and branches. Growth forms are apparently related to hydraulic energy. Rhodoliths vary from leafy, crustose, and open-branched forms in muddy sediments to dense, crustose, and radial-branching forms in coarse grainstones. Rhodolith form and internal structure correlate closely with hydraulic energy. Coralline genera are conservative and, as such, are useful in paleoenvironmental analysis. Of particular interest are the restricted depth ranges of recent coralline genera. More research is needed on the sedimentology, paleoecology, and systematics of the Cenozoic corallines, as they have particular value in paleoenvironmental analysis.

  17. Mg(2+)/Ca(2+) promotes the adhesion of marine bacteria and algae and enhances following biofilm formation in artificial seawater.

    PubMed

    He, Xiaoyan; Wang, Jinpeng; Abdoli, Leila; Li, Hua

    2016-10-01

    Adhesion of microorganisms in the marine environment is essential for initiation and following development of biofouling. A variety of factors play roles in regulating the adhesion. Here we report the influence of Ca(2+) and Mg(2+) in artificial seawater on attachment and colonization of Bacillus sp., Chlorella and Phaeodactylum tricornutum on silicon wafer. Extra addition of the typical divalent cations in culturing solution gives rise to significantly enhanced adhesion of the microorganisms. Mg(2+) and Ca(2+) affect the adhesion of Bacillus sp. presumably by regulating aggregation and formation of extracellular polymeric substances (EPS). The ions alter quantity and types of the proteins in EPS, in turn affecting subsequent adhesion. However, it is noted that Mg(2+) promotes adhesion of Chlorella likely by regulating EPS formation and polysaccharide synthesis. Ca(2+) plays an important role in protein expression to enhance the adhesion of Chlorella. For Phaeodactylum tricornutum, Ca(2+) expedites protein synthesis for enhanced adhesion. The results shed some light on effective ways of utilizing divalent cations to mediate formation of biofilms on the marine structures for desired performances. PMID:27362920

  18. Cellular Auxin Transport in Algae

    PubMed Central

    Zhang, Suyun; van Duijn, Bert

    2014-01-01

    The phytohormone auxin is one of the main directors of plant growth and development. In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. Algae are a group of relatively simple, autotrophic, photosynthetic organisms that share many features with land plants. In particular, Charophyceae (a taxon of green algae) are closest ancestors of land plants. In the study of auxin function, transport and its evolution, the algae form an interesting research target. Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies. PMID:27135491

  19. Cellular Auxin Transport in Algae.

    PubMed

    Zhang, Suyun; van Duijn, Bert

    2014-01-01

    The phytohormone auxin is one of the main directors of plant growth and development. In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. Algae are a group of relatively simple, autotrophic, photosynthetic organisms that share many features with land plants. In particular, Charophyceae (a taxon of green algae) are closest ancestors of land plants. In the study of auxin function, transport and its evolution, the algae form an interesting research target. Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies. PMID:27135491

  20. 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

  1. Respiratory Chain of Colorless Algae II. Cyanophyta

    PubMed Central

    Webster, D. A.; Hackett, D. P.

    1966-01-01

    Whole cell difference spectra of the blue-green algae, Saprospira grandis, Leucothrix mucor, and Vitreoscilla sp. have one, or at the most 2, broad α-bands near 560 mμ. At −190° these bands split to give 4 peaks in the α-region for b and c-type cytochromes, but no α-band for a-type cytochromes is visible. The NADH oxidase activity of these organisms was shown to be associated with particulate fractions of cell homogenates. The response of this activity to inhibitors differed from the responses of the NADH oxidase activities of particulate preparations from the green algae and higher plants to the same inhibitors, but is more typical of certain bacteria. No cytochrome oxidase activity was present in these preparations. The respiration of Saprospira and Vitreoscilla can be light-reversibly inhibited by CO, and all 3 organisms have a CO-binding pigment whose CO complex absorbs near 570, 535, and 417 mμ. The action spectrum for the light reversal of CO-inhibited Vitreoscilla respiration shows maxima at 568, 534, and 416 mμ. The results suggest that the terminal oxidase in these blue-greens is an o-type cytochrome. Images PMID:5932404

  2. Optimisation of sample treatment for arsenic speciation in alga samples by focussed sonication and ultrafiltration.

    PubMed

    Salgado, S García; Quijano Nieto, M A; Bonilla Simón, M M

    2006-02-28

    A procedure for arsenic species fractionation in alga samples (Sargassum fulvellum, Chlorella vulgaris, Hizikia fusiformis and Laminaria digitata) by extraction is described. Several parameters were tested in order to evaluate the extraction efficiency of the process: extraction medium, nature and concentration (tris(hydroxymethyl)aminomethane, phosphoric acid, deionised water and water/methanol mixtures), extraction time and physical treatment (magnetic stirring, ultrasonic bath and ultrasonic focussed probe). The extraction yield of arsenic under the different conditions was evaluated by determining the total arsenic content in the extracts by ICP-AES. Arsenic compounds were extracted in 5mL of water by focussed sonication for 30s and subsequent centrifugation at 14,000xg for 10min. The process was repeated three times. Extraction studies show that soluble arsenic compounds account for about 65% of total arsenic. An ultrafiltration process was used as a clean-up method for chromatographic analysis, and also allowed us to determine the extracted arsenic fraction with a molecular weight lower than 10kDa, which accounts for about 100% for all samples analysed. Speciation studies were carried out by HPLC-ICP-AES. Arsenic species were separated on a Hamilton PRP-X100 column with 17mM phosphate buffer at pH 5.5 and 1.0mLmin(-1) flow rate. The chromatographic method allowed us to separate the species As(III), As(V), MMA and DMA in less than 13min, with detection limits of about 20ng of arsenic per species, for a sample injection volume of 100muL. The chromatographic analysis allowed us to identify As(V) in Hizikia (46+/-2mugg(-1)), Sargassum (38+/-2mugg(-1)) and Chlorella (9+/-1mugg(-1)) samples. The species DMA was also found in Chlorella alga (13+/-1mugg(-1)). However, in Laminaria alga only an unknown arsenic species was detected, which eluted in the dead volume. PMID:18970494

  3. Evaluation of the contamination of marine algae (seaweed) from the St. Lawrence River and likely to be consumed by humans

    SciTech Connect

    Phaneuf, D.; Cote, I.; Dumas, P.; Ferron, L.A.; LeBlanc, A.

    1999-02-01

    The goal of the study was to assess the contamination of marine algae (seaweeds) growing in the St. Lawrence River estuary and Gulf of St. Lawrence and to evaluate the risks to human health from the consumption of these algae. Algae were collected by hand at low tide. A total of 10 sites on the north and south shores of the St. Lawrence as well as in Baie des Chaleurs were sampled. The most frequently collected species of algae were Fucus vesiculosus, Ascophyllum nodosum, Laminaria Longicruris, Palmaria palmata, Ulva lactuca, and Fucus distichus. Alga samples were analyzed for metals iodine, and organochlorines. A risk assessment was performed using risk factors. In general, concentrations in St. Lawrence algae were not very high. Consequently, health risks associated with these compounds in St. Lawrence algae were very low. Iodine concentration, on the other hand, could be of concern with regard to human health. Regular consumption of algae, especially of Laminaria sp., could result in levels of iodine sufficient to cause thyroid problems. For regular consumers, it would be preferable to choose species with low iodine concentrations, such as U. lactuca and P. palmata, in order to prevent potential problems. Furthermore, it would also be important to assess whether preparation for consumption or cooking affects the iodine content of algae. Algae consumption may also have beneficial health effects. Scientific literature has shown that it is a good source of fiber and vitamins, especially vitamin B{sub 12}.

  4. Effects of various organic chemicals on the regreening of red colored Chlorella zofingiensis.

    PubMed

    Irmer, U; Heuer, K; Weber, A

    1985-02-01

    Under nitrogen-deficient culture conditions Chlorella zofingiensis decomposes the chlorophylls, synthesizes secondary cartenoids, and thus develops red colored resting stages (akinetes). On transfer of the akinetes into nitrogen-containing fresh culture medium the algae regreen completely within a short period. The results of the experiments presented in this study show that the regreening process reacts with high sensitivity to the addition of environmentally hazardous chemicals. This system proved to be much more sensitive than other methods of testing for ecotoxicity. This screening test is universally applicable and offers, in addition, the possibility of testing volatile compounds since it is carried out in air-tight culture vessels. A phytotoxicity of 50% calculated as inhibition of the chlorophyll biosynthesis during exposure for 48 hr was found for paraquat at concentrations of 0.15 microM (added as methysulfate) and 0.28 microM (added as chloride) and for pentachlorophenol (PCP) at 0.16 microM. The chemicals 2- and 4-nitrophenol, however, proved to be much less toxic. Here, a 50% inhibition of chlorophyll biosynthesis was observed at 49 and 75 microM. When exposed to 4-chloroaniline even concentrations of 200 microM were not sufficient to cause a 50% inhibition of the regreening process. In additional experiments the influence of increasing salt concentrations (NaCl stress) and simultaneous exposure to the toxicants was examined. A step-by-step increase in the salinity of the experimental medium resulted in a drastic reduction of the toxicity caused by the addition of paraquat. This effect was much less pronounced when PCP was employed as toxicant. A different result was obtained with 2-nitrophenol: Here the toxic action was slightly enhanced. Differences in the time-dependent toxic response were also observed using the diverse toxicants. Probable causes are discussed. PMID:3987586

  5. 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

  6. 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

  7. Rapid algal toxicity assay using variable chlorophyll fluorescence for Chlorella kessleri (chlorophyta).

    PubMed

    Kvíderová, Jana

    2010-12-01

    Three methods of algal assays--the standard assay, microassay, and the proposed fluorescence assay--are compared from the point of view of reliability of EC50 detection, the minimum required time for the detection, sensitivity of individual measurement, i.e. at which cell density the particular assay can be used for EC50 estimation, and the time stability of the EC50 values. The assays were performed with green alga Chlorella kessleri strain LARG/1 growing in potassium dichromate solution in Z-medium ranging from 0.01 to 100 mg Cr L⁻¹. The inoculation cell density was set according to the standards to 10⁴ cells mL⁻¹ and according to spectrophotometer/plate reader detection limit. The average EC50 ranged from 0.096 to 0.649 mg Cr L⁻¹ and there were no significant differences in EC50 between the assay type and the inoculation methods with the exception of the significant difference between EC(c)50₇₂ (EC50 established from biomass measured as chlorophyll a concentration after 72 h of cultivation) in the standard assay and EC(r)50 (EC50 derived from growth rate) in the microassay in the standard inoculation experiment due to low variability of their values. The EC(f)50 (EC50 derived from variable fluorescence measurement) values correspond to EC50 values derived from the growth rates. Fluorescence measurement revealed the toxic effect of the chromium after 24 h of exposure at cell density of 5 x 10⁴ cells mL⁻¹, less by half than other used assay methods. The positive correlation of EC(f)50 and time was found in the standard inoculation experiment but opposite effect was observed at the spectrophotometric one. PMID:19551890

  8. 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

  9. Lipid accumulation and growth characteristics of Chlorella zofingiensis under different nitrate and phosphate concentrations.

    PubMed

    Feng, Pingzhong; Deng, Zhongyang; Fan, Lu; Hu, Zhengyu

    2012-10-01

    To evaluate the potential of the green agla Chlorella zofingiensis as a feedstock for biodiesel production, the effects of nitrogen and phosphate on lipid accumulation and growth of C. zofingiensis were studied. The maximum specific growth rate (μ(max)) reached 2.15 day⁻¹ when the concentration of NaNO₃ and K₂HPO₄·3H₂O was 1.0 g L⁻¹ and 0.01 g L⁻¹, respectively. The lipid contents of C. zofingiensis grown in media deficient of nitrogen (65.1%) or phosphate (44.7%) were both higher than that obtained from cells grown in full medium (33.5%). The highest lipid productivity (87.1 mg L⁻¹ day⁻¹) was also obtained from cells grown in nitrogen deficient media, indicating nitrogen deficiency was more effective than phosphate deficiency for inducing lipid accumulation in C. zofingiensis. In addition, the feasibility of cultivating the alga in 60 L flat plate photobioreactors and 10 L bottles outdoors for biodiesel was also tested. It was found that C. zofingiensis could adapt to fluctuating temperatures and irradiance of outdoors and the highest μ(max) and lipid productivity could reach 0.362 day⁻¹ and 26.6 mg L⁻¹ day⁻¹ outdoors, respectively. The lipid production potential of C. zofingiensis is projected to be 31.1 kg ha⁻¹ day⁻¹ in outdoor culture. These results suggested that C. zofingiensis is a promising organism for feedstock production of biofuel and can be used in scaled up culture outdoors. PMID:22698727

  10. 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. PMID:24645476

  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. 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

  13. Extra- and intra-cellular accumulation of platinum group elements by the marine microalga, Chlorella stigmatophora.

    PubMed

    Shams, Leyla; Turner, Andrew; Millward, Geoffrey E; Brown, Murray T

    2014-03-01

    To better understand the marine biogeochemistry of the platinum group elements (PGE), Rh(III), Pd(II) and Pt(IV) were added in combination and at ppb concentrations to cultures of the marine microalga, Chlorella stigmatophora, maintained in sea water at 15 °C and under 60 μmol m(-2) s(-1) PAR. The accumulation of PGE was established in short-term (24-h) exposures, and under varying conditions of algal biomass and PGE concentration, and in a longer-term exposure (156-h) by ICP-MS analysis of sea water and nitric acid digests and EDTA washes of the alga. In short-term exposures, and under all conditions, the extent of accumulation by C. stigmatophora was in the order: Rh > Pd > Pt; and Pd was internalised (or resistant to EDTA extraction) to a considerably greater extent than Rh and Pt. Accumulation isotherms were quasi-linear up to added PGE concentrations of 30 μg L(-1) and all metals displayed a significant reduction in accumulation on a weight-normalised basis with increasing density (biomass) of C. stigmatophora, an effect attributed to the production of exudates able to stabilise metals in sea water through complexation. In the longer-term exposure, kinetic constraints on the reactivities of Rh and, in particular, Pt, resulted in final degrees of accumulation and internalisation by C. stigmatophora that were greatest for Rh and similar between Pd and Pt. Among the PGE, therefore, Rh is predicted to participate in biological removal and transport processes in the marine environment to the greatest extent while decoupling in the biogeochemistries of Pd and Pt is predicted in shorter-term or more transient processes. PMID:24268058

  14. Ecology of Harmful Algae

    NASA Astrophysics Data System (ADS)

    Roelke, Daniel L.

    2007-07-01

    Edna Graneli and Jefferson T. Turner, Editors;Ecological Studies Series, Vol. 189; Springer; ISBN 3540322094; 413 pp.; 2006; $195 Harmful algal blooms (HABs) affect commercially and recreationally important species, human health, and ecosystem functioning. Hallmark events are the visually stunning blooms where waters are discolored and filled with ichthyotoxin-producing algae that lead to large fish kills. Of most concern, however, are HABs that pose a threat to human health. For example, some phycotoxins bioaccumulate in the guts and tissues of commercially and recreationally important species that when consumed by humans, may result in nausea, paralysis, memory loss, and even death. In addition to the deleterious impacts of phycotoxins, HABs can be problematic in other ways. For example, the decay of blooms often leads to low dissolved oxygen in subsurface waters. Blooms also reduce light penetration into the water column. Both processes disrupt ecosystems and in some cases have completely destroyed benthic communities.

  15. Ca2+-regulated cyclic electron flow supplies ATP for nitrogen starvation-induced lipid biosynthesis in green alga

    PubMed Central

    Chen, Hui; Hu, Jinlu; Qiao, Yaqin; Chen, Weixian; Rong, Junfeng; Zhang, Yunming; He, Chenliu; Wang, Qiang

    2015-01-01

    We previously showed that both the linear photosynthetic electron transportation rate and the respiration rate dropped significantly during N starvation-induced neutral lipid accumulation in an oil-producing microalga, Chlorella sorokiniana, and proposed a possible role for cyclic electron flow (CEF) in ATP supply. In this study, we further exploited this hypothesis in both Chlorella sorokiniana C3 and the model green alga Chlamydomonas. We found that both the rate of CEF around photosystem I and the activity of thylakoid membrane-located ATP synthetase increased significantly during N starvation to drive ATP production. Furthermore, we demonstrated that the Chlamydomonas mutant pgrl1, which is deficient in PGRL1-mediated CEF, accumulated less neutral lipids and had reduced rates of CEF under N starvation. Further analysis revealed that Ca2+ signaling regulates N starvation-induced neutral lipid biosynthesis in Chlamydomonas by increasing calmodulin activity and boosting the expression of the calcium sensor protein that regulates Pgrl1-mediated CEF. Thus, Ca2+-regulated CEF supplies ATP for N starvation-induced lipid biosynthesis in green alga. The increased CEF may re-equilibrate the ATP/NADPH balance and recycle excess light energy in photosystems to prevent photooxidative damage, suggesting Ca2+-regulated CEF also played a key role in protecting and sustaining photosystems. PMID:26450399

  16. Ca(2+)-regulated cyclic electron flow supplies ATP for nitrogen starvation-induced lipid biosynthesis in green alga.

    PubMed

    Chen, Hui; Hu, Jinlu; Qiao, Yaqin; Chen, Weixian; Rong, Junfeng; Zhang, Yunming; He, Chenliu; Wang, Qiang

    2015-01-01

    We previously showed that both the linear photosynthetic electron transportation rate and the respiration rate dropped significantly during N starvation-induced neutral lipid accumulation in an oil-producing microalga, Chlorella sorokiniana, and proposed a possible role for cyclic electron flow (CEF) in ATP supply. In this study, we further exploited this hypothesis in both Chlorella sorokiniana C3 and the model green alga Chlamydomonas. We found that both the rate of CEF around photosystem I and the activity of thylakoid membrane-located ATP synthetase increased significantly during N starvation to drive ATP production. Furthermore, we demonstrated that the Chlamydomonas mutant pgrl1, which is deficient in PGRL1-mediated CEF, accumulated less neutral lipids and had reduced rates of CEF under N starvation. Further analysis revealed that Ca(2+) signaling regulates N starvation-induced neutral lipid biosynthesis in Chlamydomonas by increasing calmodulin activity and boosting the expression of the calcium sensor protein that regulates Pgrl1-mediated CEF. Thus, Ca(2+)-regulated CEF supplies ATP for N starvation-induced lipid biosynthesis in green alga. The increased CEF may re-equilibrate the ATP/NADPH balance and recycle excess light energy in photosystems to prevent photooxidative damage, suggesting Ca(2+)-regulated CEF also played a key role in protecting and sustaining photosystems. PMID:26450399

  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. Complexity and idiosyncrasy in the responses of algae to disturbance in mono- and multi-species assemblages.

    PubMed

    Goodsell, P J; Underwood, A J

    2008-09-01

    There is considerable debate about whether stability (e.g. inertia) of an assemblage, or of individuals in an assemblage, is positively associated with the number of species or whether there are idiosyncratic effects of particular species. We assessed the general model that the loss of an individual alga, caused by trampling, is greater in monospecific than in multi-species stands but that the responses of algae are idiosyncratic, depending on the morphology of the species. The experiment was done on conspicuous and dominant algae with different morphology on temperate Australian rocky shores: the fucalean algae Hormosira banksii and Sargassum sp. and the coralline alga Corallina officinalis. We assessed the relative and interactive effects of the extent of trampling (number of paths) and the localised intensity of trampling (number of travels per path) on the three algae. The number of paths trampled (the extent of disturbance) had more impact on each alga than the number of times paths were travelled (the intensity of disturbance). As predicted, H. banksii was most susceptible to trampling at each level than were the coarser algae Sargassum sp. and C. officinalis. There was a consistent trend for each alga to be more inert to trampling when in the presence of the other two species than when in monospecific stands, but this was only statistically significant (P < 0.05) for the softer alga H. banksii. The responses of H. banksii and Sargassum sp. to disturbance seemed, in many cases, to be due to the presence of C. officinalis rather than to "diversity" per se. The relationship between the number of species and stability is complex in intertidal habitats, depending on the species and the combinations of species with which it grows. PMID:18574597

  19. Fuel From Algae: Scaling and Commercialization of Algae Harvesting Technologies

    SciTech Connect

    2010-01-15

    Broad Funding Opportunity Announcement Project: Led by CEO Ross Youngs, AVS has patented a cost-effective dewatering technology that separates micro-solids (algae) from water. Separating micro-solids from water traditionally requires a centrifuge, which uses significant energy to spin the water mass and force materials of different densities to separate from one another. In a comparative analysis, dewatering 1 ton of algae in a centrifuge costs around $3,400. AVS’s Solid-Liquid Separation (SLS) system is less energy-intensive and less expensive, costing $1.92 to process 1 ton of algae. The SLS technology uses capillary dewatering with filter media to gently facilitate water separation, leaving behind dewatered algae which can then be used as a source for biofuels and bio-products. The biomimicry of the SLS technology emulates the way plants absorb and spread water to their capillaries.

  20. Ecotoxicological effects of Mikado and Viper on algae and daphnids.

    PubMed

    Marques, C R; Gonçalves, A M M; Pereira, R; Gonçalves, F

    2012-12-01

    The toxicity of single and combined formulated herbicides (Mikado and Viper) was assessed on several endpoints in species from two trophic levels: algae growth-Pseudokirchneriella subcapitata and Chlorella vulgaris-immobilization and life-history traits (only for single compound toxicity) of daphnids-Daphnia longispina and Daphnia magna. Viper was the most toxic formulated herbicide. It was hypothesized that the toxicity of both formulated herbicides could have been enhanced by adjuvants, especially for Viper. In most cases, the sublethal endpoints were the most sensitive and affected by both formulations, comparatively to their acute effects. Concentration addition (CA) and independent action (IA) models provided an accurate description of Mikado and Viper joint action on algae growth and immobilization of daphnids, although significant deviations were always detected. A low-dose antagonism and high-dose synergism were identified for P. subcapitata, whereas C. vulgaris response deviated antagonistically from CA and synergistically from IA. For both daphnids, however, synergistic effects were observed for higher mixture concentrations. Under a regulatory standpoint, CA provided the most conservative estimation either because the mixture effects were overestimated or less subestimated than IA. Overall, the great sensitivity differences observed within species did not allow the conclusion that one trophic level was more tolerant than the other. Instead, P. subcapitata was always the most sensitive species to both herbicide formulations, followed by D. longispina, while D. magna and C. vulgaris were the most tolerant species. On a whole, further studies are needed toward a comprehensive understanding of herbicides mode of action, their effects at lower biological-level endpoints, and under different mixture designs. PMID:21374788

  1. Assimilation efficiency of organic contaminants from algae by the zebra mussel, Dreissena polymorpha

    SciTech Connect

    Goldenstein, T.A.; Bruner, K.A.; Fisher, S.W.; Landrum, P.F.

    1995-12-31

    A high percent of hydrophobic contaminants in the Great Lakes are particulate bound. Due to large populations and its high filtering capacity, the zebra mussel, Dreissena polymorpha, has the potential to re-direct contaminants from the water column by removal of contaminated particles, including algae. Throughout a season, zebra mussels feed on a variety of algal species. To determine if there are algal species differences in assimilation efficiency of contaminants, the percent assimilation efficiency (%AE) of three PCB congeners and DDE from three algae species were investigated using pulse-chase methodology. Results suggest no species difference in %AE for hexachlorobiphenyl (HCBP) from the algae Chlorella vulgaris and Chlamydomonas rheinhardtii. The mean %AE of HCBP from C. vulgaris was 60.9 (SE = {+-} 4.1), as compared to 68.6 (SE = {+-} 2.9) from C. rheinhardtii. Results from additional compounds and algal species will be discussed. The results of this study will allow them to refine the mechanism of contaminant uptake in aquatic filter feeders and assess the effect of zebra mussels on contaminant cycling in the Great lakes.

  2. Microbial fuel cell with an algae-assisted cathode: A preliminary assessment

    NASA Astrophysics Data System (ADS)

    González del Campo, Araceli; Cañizares, Pablo; Rodrigo, Manuel A.; Fernández, Francisco J.; Lobato, Justo

    2013-11-01

    A microbial fuel cell (MFC) with an algae-assisted cathode, i.e., a system where the oxygen required by the cathode is not provided by aeration but by the photosynthetic process of the algae (Chlorella vulgaris), has been studied. The cathode was illuminated for 12 h each day (from 8:00 h to 20:00 h). 25 days was necessary to achieve steady state conditions. The time evolution of dissolved oxygen and cell voltage were assessed over the course of each day. As expected, the dissolved oxygen values were not constant throughout the day, reaching maximum values between 14:00 h and 20:00 h when dark phase reactions began and the algae started to consume oxygen. Cell voltage (Rext 120 Ω) followed the same trend as the oxygen profile. The supply of CO2 in the cathode was also studied, and half an hour was enough time to get the system working properly. During the acclimation stage, power density increased up to 13.5 mW m-2 at steady state conditions. However, impedance analysis showed that polarization resistance was higher at the cathode than at the anode. Nevertheless, it can be concluded that the studied system is a feasible method to treat wastewater in a self-sustainable way.

  3. The role of exopolymeric substances in the bioaccumulation and toxicity of Ag nanoparticles to algae.

    PubMed

    Zhou, Kaijun; Hu, Yi; Zhang, Luqing; Yang, Kun; Lin, Daohui

    2016-01-01

    Exopolymeric substances (EPS) have an important role in bioaccumulation and toxicity of nanoparticles (NPs) to algae, which warrants specific studies. The interaction of EPS with citrate and polyvinyl pyrrolidone (PVP) coated AgNPs (C-AgNPs and P-AgNPs, respectively) and its roles in bioaccumulation and toxicity of the AgNPs to Chlorella pyrenoidosa were investigated. The amino and aromatic carboxylic groups in the EPS were involved in the EPS-AgNP interactions. Compared with Ag(+), C-AgNPs had comparable total bioaccumulation but greater absorption by intact algae with EPS; P-AgNPs had the smallest total bioaccumulation and were mainly adsorbed on algal surfaces. With EPS removed, the total bioaccumulations and surface adsorptions for the three Ag species decreased but the cell internalizations increased; the 96 h half growth inhibition concentrations decreased, indicating EPS alleviated the algal toxicity of Ag. The cell-internalized but not the adsorbed AgNPs could contribute to the nanotoxicity. The EPS could bind both AgNPs and Ag(+), and thus inhibited the cell internalization and the nanotoxicity. However, the EPS-bound Ag on the cell surfaces would migrate along with the algae and be biologically amplified in the aquatic food chains, presenting ecological risks. These results are helpful for understanding the fate and ecological effects of NPs. PMID:27615743

  4. Transgenic algae engineered for higher performance

    DOEpatents

    Unkefer, Pat J; Anderson, Penelope S; Knight, Thomas J

    2014-10-21

    The present disclosure relates to transgenic algae having increased growth characteristics, and methods of increasing growth characteristics of algae. In particular, the disclosure relates to transgenic algae comprising a glutamine phenylpyruvate transaminase transgene and to transgenic algae comprising a glutamine phenylpyruvate transaminase transgene and a glutamine synthetase.

  5. Energetic metabolism response in algae and higher plant species from simulation experiments with the clinostat.

    PubMed

    Vasilenko, A; Popova, A F

    1996-01-01

    Adenylate state is acknowledged to be among the most convenient approaches in the study of physiological changes in plant cells under simulation of altered gravity condition with the clinostat. Adenylate levels and the ATP/ADP ratio in cytoplasmic and mitochondrial extracts of cultivated cells of Haplopappus gracilis and algae cells of Chlorella vulgaris under initial stages of the fast-rotating and slow-rotating clinorotation, as well as the long-term clinorotation, have been investigated. For analysis of ATP and ADP levels in the plant cells under the clinorotation, we applied a high-sensitive bioluminescence method using the luciferase and piruvate kinase enzyme systems. It has been shown that the adenylate ratio is already increased during at the start of clinorotation with the different speed of rotation in the biological material tested. The considerable changes in mitochondrial ultrastructure of Chlorella cells, as well as the rising ATP level and dropping of the ATP/ADP ratio appear after long-duration clinorotation if compared to control material. It is probably connected with the distinctions in ATP-synthetase functioning in mitochondria of the cells under the clinorotation conditions. PMID:11538600

  6. Energetic metabolism response in algae and higher plant species from simulation experiments with the clinostat

    NASA Astrophysics Data System (ADS)

    Vasilenko, A.; Popova, A. F.

    Adenylate state is acknowledged to be among the most convenient approaches in the study of physiological changes in plant cells under simulation of altered gravity condition with the clinostat. Adenylate levels and the ATP/ADP ratio in cytoplasmic and mitochondrial extracts of cultivated cells of Haplopappus gracilis and algae cells of Chlorella vulgaris under initial stages of the fast-rotating and slow-rotating clinorotation, as well as the long-term clinorotation, have been investigated. For analysis of ATP and ADP levels in the plant cells under the clinorotation, we applied a high-sensitive bioluminescence method using the luciferase and piruvate kinase enzyme systems. It has been shown that the adenylate ratio is already increased during at the start of clinorotation with the different speed of rotation in the biological material tested. The considerable changes in mitochondrial ultrastructure of Chlorella cells, as well as the rising ATP level and dropping of the ATP/ADP ratio appear after long-duration clinorotation if compared to control material. It is probably connected with the distinctions in ATP-synthetase functioning in mitochondria of the cells under the clinorotation conditions.

  7. Photosynthesis and photorespiration in algae.

    PubMed

    Lloyd, N D; Canvin, D T; Culver, D A

    1977-05-01

    The CO(2) exchange of several species of fresh water and marine algae was measured in the laboratory to determine whether photorespiration occurs in these organisms. The algae were positioned as thin layers on filter paper and the CO(2) exchange determined in an open gas exchange system. In either 21 or 1% O(2) there was little difference between (14)CO(2) and (12)CO(2) uptake. Apparent photosynthesis was the same in 2, 21, or 50% O(2). The compensation points of all algae were less than 10 mul 1(-1). CO(2) or (14)CO(2) evolution into CO(2)-free air in the light was always less than the corresponding evolution in darkness. These observations are inconsistent with the proposal that photorespiration exists in these algae. PMID:16659972

  8. Cambrian calcareous algae and bacteria

    NASA Astrophysics Data System (ADS)

    Luchinina, Veronica A.; Terleev, A. A.

    2003-01-01

    Individual calcareous algae were known in Riphean. Their mass distribution is connected to the beginning of Cambrian. Despite of a long history of study, the nature of this group long time remained not clear. The new unique finds of algae from East Sayan region have shown, that primary carbonate thallus disappeared in the process of fossilization, and after it the calcareous cover formed by association of bacteria and cyanobacteria only.

  9. Viruses of eukaryotic green algae; Progress report, June 20, 1990--July 1, 1991

    SciTech Connect

    Van Etten, J.L.

    1991-12-31

    Many large polyhedral, dsDNA containing (ca. 330 kb), plaque forming viruses which infect a unicellular, eukaryotic, chlorella-like green alga have been isolated and characterized. The plaque assay, the ability to synchronously infect the host, the short life cycle, and the ability of the viruses to undergo homologous recombination make them excellent model systems for studying many plant cell functions in the manner that bacterial and animal viruses have been used to study bacterial and animal cell functions. These viruses have several unique features including: (1) coding for DNA methyltransferase and site-specific (restriction) endonucleases and (2) unlike other viruses, these viruses appear to code for the enzymes involved in the glycosylation of their glycoproteins.

  10. Facile Algae-Derived Route to Biogenic Silver Nanoparticles: Synthesis, Antibacterial, and Photocatalytic Properties.

    PubMed

    Aziz, Nafe; Faraz, Mohd; Pandey, Rishikesh; Shakir, Mohd; Fatma, Tasneem; Varma, Ajit; Barman, Ishan; Prasad, Ram

    2015-10-27

    Biogenic synthesis of metal nanoparticles is of considerable interest, as it affords clean, biocompatible, nontoxic, and cost-effective fabrication. Driven by their ability to withstand variable extremes of environmental conditions, several microorganisms, notably bacteria and fungi, have been investigated in the never-ending search for optimal nanomaterial production platforms. Here, we present a hitherto unexplored algal platform featuring Chlorella pyrenoidosa, which offers a high degree of consistency in morphology of synthesized silver nanoparticles. Using a suite of characterization methods, we reveal the intrinsic crystallinity of the algae-derived nanoparticles and the functional moieties associated with its surface stabilization. Significantly, we demonstrate the antibacterial and photocatalytic properties of these silver nanoparticles and discuss the potential mechanisms that drive these critical processes. The blend of photocatalytic and antibacterial properties coupled with their intrinsic biocompatibility and eco-friendliness make these nanoparticles particularly attractive for wastewater treatment. PMID:26447769

  11. 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.

  12. Chlorella is an effective dietary source of lutein for human erythrocytes.

    PubMed

    Miyazawa, Taiki; Nakagawa, Kiyotaka; Kimura, Fumiko; Nakashima, Yuya; Maruyama, Isao; Higuchi, Ohki; Miyazawa, Teruo

    2013-01-01

    Chlorella contains a high amount of carotenoids, especially lutein, and has received attention as a possible dietary source for improving carotenoid levels in human blood. In the present study, we performed a 2-month single arm human study, and investigated the efficacy of Chlorella supplementation (9 g Chlorella/day; equivalent to 32 mg lutein/day) on lutein and other carotenoid concentrations in plasma as well as erythrocytes of 12 healthy subjects. Following Chlorella supplementation, lutein was the predominant carotenoid in erythrocytes, showing a 4-fold increase (from 14 to 54 pmol/mL packed cells). After the one month without Chlorella ingestion, erythrocyte lutein then decreased to a basal level (17 pmol/mL packed cells). Erythrocyte carotenoid (lutein, zeaxanthin, α-carotene, and β-carotene) levels were proportional to plasma carotenoid levels. The results suggest the transfer of Chlorella carotenoids, especially lutein, from plasma lipoprotein particles to the erythrocyte membrane. Chlorella intake would be effective for improving and maintaining lutein concentrations in human erythrocytes. PMID:24088514

  13. Evolutionary Significance of an Algal Gene Encoding an [FeFe]-Hydrogenase with F-Domain Homology and Hydrogenase Activity in Chlorella Variabilis NC64A

    SciTech Connect

    Meuser, J. E.; Boyd, E. S.; Ananyev, G.; Karns, D.; Radakovits, R.; Murthy, U. M. N.; Ghirardi, M. L.; Dismukes, G. C.; Peters, J. W.; Posewitz, M. C.

    2011-10-01

    [FeFe]-hydrogenases (HYDA) link the production of molecular H{sub 2} to anaerobic metabolism in many green algae. Similar to Chlamydomonas reinhardtii, Chlorella variabilis NC64A (Trebouxiophyceae, Chlorophyta) exhibits [FeFe]-hydrogenase (HYDA) activity during anoxia. In contrast to C. reinhardtii and other chlorophycean algae, which contain hydrogenases with only the HYDA active site (H-cluster), C. variabilis NC64A is the only known green alga containing HYDA genes encoding accessory FeS cluster-binding domains (F-cluster). cDNA sequencing confirmed the presence of F-cluster HYDA1 mRNA transcripts, and identified deviations from the in silico splicing models. We show that HYDA activity in C. variabilis NC64A is coupled to anoxic photosynthetic electron transport (PSII linked, as well as PSII-independent) and dark fermentation. We also show that the in vivo H{sub 2}-photoproduction activity observed is as O2 sensitive as in C. reinhardtii. The two C. variabilis NC64A HYDA sequences are similar to homologs found in more deeply branching bacteria (Thermotogales), diatoms, and heterotrophic flagellates, suggesting that an F-cluster HYDA is the ancestral enzyme in algae. Phylogenetic analysis indicates that the algal HYDA H-cluster domains are monophyletic, suggesting that they share a common origin, and evolved from a single ancestral F-cluster HYDA. Furthermore, phylogenetic reconstruction indicates that the multiple algal HYDA paralogs are the result of gene duplication events that occurred independently within each algal lineage. Collectively, comparative genomic, physiological, and phylogenetic analyses of the C. variabilis NC64A hydrogenase has provided new insights into the molecular evolution and diversity of algal [FeFe]-hydrogenases.

  14. Measurement of photorespiration in algae.

    PubMed

    Birmingham, B C; Coleman, J R; Colman, B

    1982-01-01

    The rates of true and apparent photosynthesis of two unicellular green algae, one diatom and four blue-green algae were measured in buffer at pH 8.0 at subsaturating concentrations of dissolved inorganic carbon (13-27 micromolar). Initial rates of depletion from the medium of inorganic carbon and (14)C activity caused by the algae in a closed system were measured by gas chromatography and by liquid scintillation counting, respectively. The rate of photorespiration was calculated as the difference between the rates of apparent and true photosynthesis. The three eucaryotic algae and two blue-green algae had photorespiratory rates of 10 to 28% that of true photosynthesis at air levels of O(2). Reduction of the O(2) level to 2% caused a 52 to 91% reduction in photorespiratory rate. Two other blue-green algae displayed low photorespiratory rates, 2.4 to 6.2% that of true photosynthesis at air levels of O(2), and reduction of the O(2) concentration had no effect on these rates. PMID:16662171

  15. 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.

  16. Geographic variation in the damselfish-red alga cultivation mutualism in the Indo-West Pacific

    PubMed Central

    2010-01-01

    Background On coral reefs, damselfish defend their territories from invading herbivores and maintain algal turfs, from which they harvest filamentous algae. In southern Japan, intensive weeding of indigestible algae by Stegastes nigricans results in overgrowth by one filamentous alga, Polysiphonia sp. 1. Because this alga is highly susceptible to grazing and is competitively inferior to other algae, it survives only within the protective territories of this fish species, suggesting an obligate mutualism between damselfish and their cultivated alga. The wide distribution of damselfish species through the Indo-Central Pacific raises the question of whether this species-specific mutualism is maintained throughout the geographic range of the fish. To address this question, from all 18 damselfish species we conducted comprehensive surveys of algal flora within their territories throughout the Indo-West Pacific, and identified species of Polysiphonia using morphological examination and gene sequencing data. Results Several species of the genus Polysiphonia were observed as a major crop in territories throughout the geographic range of S. nigricans. Polysiphonia sp. 1 occurred only in territories of S. nigricans in central areas of the Indo-Pacific. However, its occurrence was low from the Great Barrier Reef and Mauritius. In contrast, other indigenous Polysiphonia species, which formed a clade with Polysiphonia sp. 1, occurred in the territories of fishes from Egypt, Kenya, and the Maldives. The other Polysiphonia species in the clade only inhabited damselfish territories and were never found elsewhere. Conclusions Cultivation mutualism between the damselfish S. nigricans and algae of Polysiphonia was maintained throughout the Indo-West Pacific, although algal crop species and the mode of cultivation (e.g., presence/absence of selective weeding, the species composition of algal turfs) varied among localities. This finding implies that damselfish utilize indigenous

  17. Response of freshwater algae to water quality in Qinshan Lake within Taihu Watershed, China

    NASA Astrophysics Data System (ADS)

    Zhang, Jianying; Ni, Wanmin; Luo, Yang; Jan Stevenson, R.; Qi, Jiaguo

    Although frequent algal blooms in Taihu Lake in China have become major environmental problems and have drawn national and international attention, little is understood about the relationship between algal blooms and water quality. The goal of this study was to assess the growth and species responses of freshwater algae to variation in water quality in Qinshan Lake, located in headwaters of the Taihu watershed. Water samples were collected monthly from ten study sites in the Qinshan Lake and were analyzed for species distribution of freshwater algae and physiochemical parameters such as total nitrogen (TN), NH4+-N, NO3--N, total phosphorus (TP), chemical oxygen demand (COD Mn) and Chl-a. The results showed that average TN was 4.47 mg/L, with 92.2% of values greater than the TN standard set by the Chinese Environmental Protection Agency; average TP was 0.051 mg/L, with 37.9% of values above the TP national standard; and average trophic level index (TLI) was 53, the lower end of eutrophic condition. Average Chl-a concentration was 12.83 mg/m 3. Green algae and diatom far outweighed other freshwater algae and were dominant most time of the year, with the highest relative abundances of 96% and 99%, respectively. Blue-green algae, composed mainly toxic strains like Microcystis sp ., Nostoc sp. and Oscillatoria sp., became most dominant in the summer with the maximum relative abundance of 69%. The blue-green algae sank to the lake bottom to overwinter, and then dinoflagellates became the dominant species in the winter, with highest relative abundance of 89%. Analysis indicated that nutrients, especially control of ammonia and co-varying nutrients were the major restrictive factor of population growth of blue-green algae, suggesting that control in nutrient enrichments is the major preventive measure of algal blooms in Qinshan Lake.

  18. Trophic transfer potential of aluminium oxide nanoparticles using representative primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia).

    PubMed

    Pakrashi, Sunandan; Dalai, Swayamprava; Chandrasekaran, Natarajan; Mukherjee, Amitava

    2014-07-01

    The transfer of nanoparticles through the food chain can lead to bioaccumulation and biomagnification resulting in a long term negative impact on the ecosystem functions. The primary objective of this study was evaluation of aluminium oxide nanoparticles transfer from primary producers to primary consumers. A simple set up consisting of a primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia) was used. Here, C. ellipsoides were exposed to the varying concentrations of the nanoparticles ranging from 20 to 120μg/mL (196 to 1176μM) for 48h and the infested algal cells were used as the feed to C. dubia. The bioaccumulation of the nanoparticles into the daphnids was noted and the biomagnification factors were computed. The exposure was noted to cause subtle alterations in the feeding behaviour of the daphnids. This might have long term consequences in the energy flow through the food chain. The reproductive behaviour of the daphnids remained unaffected upon exposure to nanoparticle infested algal feed. Distinct observations at ultra-structural scale using transmission electron microscopy provided visual evidences for the disrupted feeding behaviour upon exposure to nanoparticle treated algae. Internalization of nanoparticle like inclusion bodies in the intracellular space of algae was also detected. The findings were further substantiated by a detailed analysis of hydrodynamic stability, bioavailability and dissolution of ions from the nanoparticles over the exposure period. Altogether, the study brings out the first of its kind of observation of trophic transfer potential/behaviour of aluminium oxide nanoparticles and its probable impacts on the energy flow in the fresh water aquatic ecosystem. PMID:24736130

  19. Outdoor cultivation of temperature-tolerant Chlorella sorokiniana in a column photobioreactor under low power-input.

    PubMed

    Béchet, Quentin; Muñoz, Raul; Shilton, Andy; Guieysse, Benoit

    2013-01-01

    Temperature-tolerant Chlorella sorokiniana was cultivated in a 51-L column photobioreactor with a 1.1 m(2) illuminated area. The reactor was operated outdoors under tropical meteorological conditions (Singapore) without controlling temperature and the culture was mixed at a power input of 7.5 W/m(3) by sparging CO(2) -enriched air at 1.2 L/min (gas hold-up of 0.02). Biomass productivity averaged 10 ± 2.2 g/m(2) -day over six batch studies, yielding an average photosynthetic efficiency (PE) of 4.8 ± 0.5% of the total solar radiation (P = 0.05, N = 6). This demonstrates that temperature-tolerant microalgae can be cultivated at high PE under a mixing input sevenfold to ninefold lower than current operational guidelines (50-70 W/m(3)) and without the need for temperature control (the culture broth temperature reached 41 °C during operation). In this study, the PE value was determined based on the amount of solar radiation actually reaching the algae and this amount was estimated using a mathematical model fed with onsite solar irradiance data. This determination was found to be particularly sensitive to the value of the atmospheric diffusion coefficient, which generated a significant uncertainty in the PE calculation. The use of the mathematical model, however, confirmed that the vertical reactor geometry supported efficient photosynthesis by reducing the duration and intensity of photoinhibition events. The model also revealed that all three components of direct, diffuse, and reflected solar radiation were quantitatively important for the vertical column photobioreactor, accounting for 14%, 65%, and 21% of the total solar radiation reaching the culture, respectively. The accurate prediction of the discrete components of solar radiation reaching the algae as a function of climatic, geographic, and design parameters is therefore crucial to optimize the individual reactor geometry and the layout/spacing between the individual reactors in a reactor farm. PMID:22767101

  20. Sorption kinetics and equilibrium of the herbicide diuron to carbon nanotubes or soot in absence and presence of algae.

    PubMed

    Schwab, Fabienne; Camenzuli, Louise; Knauer, Katja; Nowack, Bernd; Magrez, Arnaud; Sigg, Laura; Bucheli, Thomas D

    2014-09-01

    Carbon nanotubes (CNT) are strong sorbents for organic micropollutants, but changing environmental conditions may alter the distribution and bioavailability of the sorbed substances. Therefore, we investigated the effect of green algae (Chlorella vulgaris) on sorption of a model pollutant (diuron, synonyms: 3-(3,4-Dichlorophenyl)-1,1-dimethylurea, DCMU) to CNT (multi-walled purified, industrial grade, pristine, and oxidized; reference material: Diesel soot). In absence of algae, diuron sorption to CNT was fast, strong, and nonlinear (Freundlich coefficients: 10(5.79)-10(6.24) μg/kgCNT·(μg/L)(-n) and 0.62-0.70 for KF and n, respectively). Adding algae to equilibrated diuron-CNT mixtures led to 15-20% (median) diuron re-dissolution. The relatively high amorphous carbon content slowed down ad-/desorption to/from the high energy sorption sites for both industrial grade CNT and soot. The results suggest that diuron binds readily, but - particularly in presence of algae - partially reversibly to CNT, which is of relevance for environmental exposure and risk assessment. PMID:24949853

  1. Evaluation of toxicity data to green algae and relationship with hydrophobicity.

    PubMed

    Fu, Ling; Li, Jin J; Wang, Yu; Wang, Xiao H; Wen, Yang; Qun, Wei C; Su, Li M; Zhao, Yuan H

    2015-02-01

    The quality of the biological activity data is of great importance for the development of algal quantitative structure-activity relationship (QSAR) models. However, a number of algal QSAR models in the literature were developed based on toxicity data without considering the response endpoints, exposure periods and species sensitivity. In this paper, 2323 algal toxicity data (log 1/EC50) in different toxicity response endpoints for 1081 compounds to 26 algal species within different exposure periods (14 and 15 min; 24, 48, 72, 96, 168 and 192 h) were used to evaluate the quality of the toxicity data to green algae. Analysis of 72 h toxicity to algae showed that the closed test had the same sensitivity as the open test for most of the test compounds, but a significant difference was observed for a few compounds. The overall average difference for all compounds ranges from 0.15 to 0.43 log units between toxicity endpoints (yield–growth rate). The relationships between exposure periods of 24, 48, 72 and 96 h indicated that 48 h exposure period is the most sensitive for algal growth inhibition test, and its sensitivity is 0.25 log units greater than 72 and 96 h exposure periods, respectively. Interspecies relationships showed that some algal species have very close sensitivity (e.g. Pseudokirchneriella subcapitata and Chlorella pyrenoidosa or Chlorella vulgaris and Scenedesmus obliquus, respectively), whereas some species have significantly different sensitivity (e.g. P. subcapitata and S. obliquus). Relationships between toxicity and hydrophobicity demonstrated that no difference was observed for non-polar narcotics within different exposure periods (24, 48, 72, and 96 h) or response variables (yield and growth rate). For polar narcotics, in contrast, algal toxicity is dependent on algal species and is related to the response variables and exposure period. We cannot expect significant QSAR models between algal toxicity and descriptors without considering species

  2. Simultaneous increases in specific growth rate and specific lipid content of Chlorella vulgaris through UV-induced reactive species.

    PubMed

    Balan, Ranjini; Suraishkumar, G K

    2014-01-01

    A challenge in algae-based bio-oil production is to simultaneously enhance specific growth rates and specific lipid content. We have demonstrated simultaneous increases in both the above in Chlorella vulgaris through reactive species (RS) induced under ultraviolet (UV) A and UVB light treatments. We postulated that the changes in photosystem (PS) stoichiometry and antenna size were responsible for the increases in specific growth rate. UVB treatment excited PSII, which resulted in a twofold to sevenfold increase in PSII/PSI ratio compared to control. An excited PSII caused a 2.7-fold increase in the specific levels of superoxide and a twofold increase in the specific levels of hydroxyl radicals. We have established that the increased specific intracellular RS (si-RS) levels increased the PSII antenna size by a significant 10-fold as compared to control. In addition, the 8.2-fold increase in specific lipid content was directly related to the si-RS levels. We have also demonstrated that the RS induced under UVA treatment led to a 3.2-fold increase in the saturated to unsaturated fatty acid ratio. Based on the findings, we have proposed and demonstrated a UV-based strategy, which achieved an 8.8-fold increase in volumetric lipid productivity. PMID:24382840

  3. 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. PMID:26878360

  4. 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. PMID:25307462

  5. Light attenuates lipid accumulation while enhancing cell proliferation and starch synthesis in the glucose-fed oleaginous microalga Chlorella zofingiensis

    PubMed Central

    Chen, Tianpeng; Liu, Jin; Guo, Bingbing; Ma, Xiaonian; Sun, Peipei; Liu, Bin; Chen, Feng

    2015-01-01

    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. PMID:26442783

  6. Potential toxic effect of trifloxystrobin on cellular microstructure, mRNA expression and antioxidant enzymes in Chlorella vulgaris.

    PubMed

    Shen, Yu-Feng; Liu, Lei; Gong, Yu-Xin; Zhu, Bin; Liu, Guang-Lu; Wang, Gao-Xue

    2014-05-01

    This study investigated the effects of trifloxystrobin that one strobilurin used widely in the world as an effective fungicidal agent to control Asian soybean rust on aquatic unicellular algae Chlorella vulgaris. We determined the potential toxic effect of trifloxystrobin on C. vulgaris, and found median inhibition concentration (IC(50)) value 255.58 (95% confidence interval, 207.81-330.29)μgL(-1). In addition, the algal cells were obviously depressed or shrunk at different concentrations by electron microscopy. In the study, a real-time polymerase chain reaction (PCR) assay showed changes in transcript abundances of three photosynthetic genes, psaB, psbC, and rbcL, and one energy gene, ATPs. The results showed that trifloxystrobin reduced the transcript abundances of the three genes and enhanced expression of ATPs after 48 and 96 h. The lowest abundances of psaB, psbC and rbcL transcripts in response to trifloxystrobin exposure were 58%, 79% and 60% of those of the control, respectively. For the potential toxic influences, trifloxystrobin could decrease the soluble protein and total antioxidant contents (T-AOC), and increase superoxide dismutase (SOD) and peroxidase (POD) activity with a gradual concentration-response relationship. Overall, the present study demonstrated that trifloxystrobin could affect the activities of antioxidant enzymes, disrupts photosynthesis in C. vulgaris, and damage cellular structure. PMID:24762415

  7. Trapping of redox-mediators at the surface of Chlorella vulgaris leads to error in measurements of cell reducing power.

    PubMed

    Thorne, Rebecca J; Hu, Huaining; Schneider, Kenneth; Cameron, Petra J

    2014-03-28

    The reduction of the redox mediator ferricyanide, [Fe(CN)6](3-), by a range of algal and bacterial species, is frequently measured to probe plasma membrane ferrireductase activity or to quantify the reducing power of algal/bacterial biofilms and suspensions. In this study we have used rotating disk electrochemistry (RDE) to investigate the reduction of ferricyanide by the model organism Chlorella vulgaris. Importantly, we have seen that the diffusion limited current due to the oxidation of ferrocyanide, [Fe(CN)6](4-), at the electrode decreased linearly as C. vulgaris was added to the solution, even though in a pure ferrocyanide solution the algae are not able to reduce the mediator further and are simply spectator 'particles'. We attribute this effect to trapping of ferrocyanide at the cell surface, with up to 14% of the ferrocyanide missing from the solution at the highest cell concentration. The result has important implications for all techniques that use electrochemistry and other concentration dependent assays (e.g. fluorescence and colourimetry) to monitor ferrocyanide concentrations in the presence of both biofilms and cell suspensions. Analyte trapping could lead to a substantial underestimation of the concentration of reduced product. PMID:24535230

  8. 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

  9. Affinity Purification of O-Acetylserine(thiol)lyase from Chlorella sorokiniana by Recombinant Proteins from Arabidopsis thaliana

    PubMed Central

    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 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

  10. Efficient Heterologous Transformation of Chlamydomonas reinhardtii npq2 Mutant with the Zeaxanthin Epoxidase Gene Isolated and Characterized from Chlorella zofingiensis

    PubMed Central

    Couso, Inmaculada; Cordero, Baldo F.; Vargas, María Ángeles; Rodríguez, Herminia

    2012-01-01

    In the violaxanthin cycle, the violaxanthin de-epoxidase and zeaxanthin epoxidase catalyze the inter-conversion between violaxanthin and zeaxanthin in both plants and green algae. The zeaxanthin epoxidase gene from the green microalga Chlorella zofingiensis (Czzep) has been isolated. This gene encodes a polypeptide of 596 amino acids. A single copy of Czzep has been found in the C. zofingiensis genome by Southern blot analysis. qPCR analysis has shown that transcript levels of Czzep were increased after zeaxanthin formation under high light conditions. The functionality of Czzep gene by heterologous genetic complementation in the Chlamydomonas mutant npq2, which lacks zeaxanthin epoxidase (ZEP) activity and accumulates zeaxanthin in all conditions, was analyzed. The Czzep gene was adequately inserted in the pSI105 vector and expressed in npq2. The positive transformants were able to efficiently convert zeaxanthin into violaxanthin, as well as to restore their maximum quantum efficiency of the PSII (Fv/Fm). These results show that Chlamydomonas can be an efficient tool for heterologous expression and metabolic engineering for biotechnological applications. PMID:23118714

  11. Genetic manipulation, a feasible tool to enhance unique characteristic of Chlorella vulgaris as a feedstock for biodiesel production.

    PubMed

    Talebi, Ahmad Farhad; Tohidfar, Masoud; Tabatabaei, Meisam; Bagheri, Abdolreza; Mohsenpor, Motahhareh; Mohtashami, Seyed Kaveh

    2013-07-01

    Developing a reliable technique to transform unicellular green algae, Chlorella vulgaris, could boost potentials of using microalgae feedstock in variety of applications such as biodiesel production. Volumetric lipid productivity (VLP) is a suitable variable for evaluating potential of algal species. In the present study, the highest VLP level was recorded for C. vulgaris (79.08 mg l(-1 )day(-1)) followed by 3 other strains studied; C. emersonii, C. protothecoides, and C. salina by 54.41, 45 and 18.22 mg l(-1)day(-1), respectively. Having considered the high productivity of C. vulgaris, it was selected for the preliminary transformation experiment through micro-particle bombardment. Plasmid pBI 121, bearing the reporter gene under the control of CaMV 35S promoter and the kanamycin marker gene, was used in cells bombardment. Primary selection was done on a medium supplemented by 50 mg l(-1) kanamycin. After several passages, the survived cells were PCR-tested to confirm the stability of transformation and then were found to exhibit β-glucuronidase (GUS) activity in comparison with the control cells. Southern hybridization of npt II probe with genomic DNA revealed stable integration of the cassette in three different positions in the genome. The whole process was successfully implemented as a pre-step to transform the algal cells by genes involved in lipid production pathway which will be carried out in our future studies. PMID:23652998

  12. Safety evaluation of Whole Algalin Protein (WAP) from Chlorella protothecoides.

    PubMed

    Szabo, Nancy J; Matulka, Ray A; Chan, Teresa

    2013-09-01

    Microalgae such as Chlorella spp., were once consumed as traditional human foods; now they are being developed as ingredients for modern diets. Whole Algalin Protein (WAP) from dried milled Chlorella protothecoides was evaluated for dietary safety in a 13-week feeding trial in rodents with genotoxic potential evaluated using in vitro and in vivo assays and the likelihood of food allergy potential evaluated via human repeat-insult patch test (HRIPT). In the subchronic study, rats consumed feed containing 0, 25,000, 50,000 or 100,000 ppm WAP for 92-93 days. No treatment-related mortalities or effects in general condition, body weight, food consumption, ophthalmology, urinalysis, hematology, clinical chemistry, gross pathology, organ weights, and histopathology occurred. Several endpoints exhibited statistically significant effects, but none was dose-related. The no-observed-adverse-effect level (NOAEL) was based on the highest WAP concentration consumed by the rats and was equivalent to 4805 mg/kg/day in males and 5518 mg/kg/day in females. No mutagenicity occurred in Salmonella typhimurium or Escherichia coli tester strains (≤5000 μg/plate WAP) with or without mutagenic activation. No clastogenic response occurred in bone marrow from mice administered a single oral dose (2000 mg/kg WAP). Skin sensitization was not induced by WAP via HRIPT, indicating little potential for food allergy. PMID:23733102

  13. Identification of aquatically available carbon from algae through solution-state NMR of whole (13)C-labelled cells.

    PubMed

    Akhter, Mohammad; Dutta Majumdar, Rudraksha; Fortier-McGill, Blythe; Soong, Ronald; Liaghati-Mobarhan, Yalda; Simpson, Myrna; Arhonditsis, George; Schmidt, Sebastian; Heumann, Hermann; Simpson, André J

    2016-06-01

    Green algae and cyanobacteria are primary producers with profound impact on food web functioning. Both represent key carbon sources and sinks in the aquatic environment, helping modulate the dissolved organic matter balance and representing a potential biofuel source. Underlying the impact of algae and cyanobacteria on an ecosystem level is their molecular composition. Herein, intact (13)C-labelled whole cell suspensions of Chlamydomonas reinhardtii, Chlorella vulgaris and Synechocystis were studied using a variety of 1D and 2D (1)H/(13)C solution-state nuclear magnetic resonance (NMR) spectroscopic experiments. Solution-state NMR spectroscopy of whole cell suspensions is particularly relevant as it identifies species that are mobile (dissolved or dynamic gels), 'aquatically available' and directly contribute to the aquatic carbon pool upon lysis, death or become a readily available food source on consumption. In this study, a wide range of metabolites and structural components were identified within the whole cell suspensions. In addition, significant differences in the lipid/triacylglyceride (TAG) content of green algae and cyanobacteria were confirmed. Mobile species in algae are quite different from those in abundance in 'classic' dissolved organic matter (DOM) indicating that if algae are major contributors to DOM, considerable selective preservation of minor components (e.g. sterols) or biotransformation would have to occur. Identifying the metabolites and dissolved components within algal cells by NMR permits future studies of carbon transfer between species and through the food chain, whilst providing a foundation to better understand the role of algae in the formation of DOM and the sequestration/transformation of carbon in aquatic environments. PMID:27074782

  14. Chlamydomonas sajao nov. sp. (Chlorophyta, Volvocales)

    NASA Astrophysics Data System (ADS)

    Lewin, Ralph A.

    1984-06-01

    A new species of Chlamydomonas, namely, C. sajao nov. sp. of the Volvocales, Chlorophyta was isolated from a duckweed growing near a ricefield in the vicinity of Guangzhou, China. This interesting unicellular green alga, similar to C. mexicana from Mexico, secretes quantities of extracellular mucilaginous polysaccharides, and may be employed in improving soil quality. The new species resembles C. waldenburgensis Moewus in most characteristics but differs in three important features.

  15. 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.

  16. Hyperosmosis and its combination with nutrient-limitation are novel environmental stressors for induction of triacylglycerol accumulation in cells of Chlorella kessleri.

    PubMed

    Hirai, Kazuho; Hayashi, Taihei; Hasegawa, Yuri; Sato, Atsushi; Tsuzuki, Mikio; Sato, Norihiro

    2016-01-01

    Triacylglycerols of oleaginous algae are promising for production of food oils and biodiesel fuel. Air-drying of cells induces triacylglycerol accumulation in a freshwater green alga, Chlorella kessleri, therefore, it seems that dehydration, i.e., intracellular hyperosmosis, and/or nutrient-limitation are key stressors. We explored this possibility in liquid-culturing C. kessleri cells. Strong hyperosmosis with 0.9 M sorbitol or 0.45 M NaCl for two days caused cells to increase the triacylglycerol content in total lipids from 1.5 to 48.5 and 75.3 mol%, respectively, on a fatty acid basis, whereas nutrient-limitation caused its accumulation to 41.4 mol%. Even weak hyperosmosis with 0.3 M sorbitol or 0.15 M NaCl, when nutrient-limitation was simultaneously imposed, induced triacylglycerol accumulation to 61.9 and 65.7 mol%, respectively. Furthermore, culturing in three-fold diluted seawater, the chemical composition of which resembled that of the medium for the combinatory stress, enabled the cells to accumulate triacylglycerol up to 24.7 weight% of dry cells in only three days. Consequently, it was found that hyperosmosis is a novel stressor for triacylglycerol accumulation, and that weak hyperosmosis, together with nutrient-limitation, exerts a strong stimulating effect on triacylglycerol accumulation. A similar combinatory stress would contribute to the triacylglycerol accumulation in air-dried C. kessleri cells. PMID:27184595

  17. Outdoor cultures of Chlorella pyrenoidosa in the effluent of anaerobically digested activated sludge: The effects of pH and free ammonia.

    PubMed

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

    2016-01-01

    A freshwater algae Chlorella pyrenoidosa was cultured outdoors using anaerobically digested activated sludge effluent. The effects of pH variations were evaluated. The coupled pH variations and free ammonia toxicity significantly affected the algal growth, lipids accumulation and contamination control during every season. The free ammonia toxicity at high pH levels actually inhibited the algal growth. Compared to an optimal algal growth at a pH of 5.7-6.5, biomass productivity at a high pH of 8.3-8.8 was reduced by 67.15±6.98%, 54.39±6.42% and 83.63±5.71% in the spring, fall and summer, respectively. When the pH rose above 9.1-9.6, algae were unable to grow in the wastewater. However, high pH levels reduced contamination (e.g., bacteria and microalgae grazers) and triggered lipids accumulation in algal cells. These findings suggest that pH control strategies are essential for this type of algal wastewater system, where ammonia is the dominant nitrogen source. PMID:26547810

  18. Hyperosmosis and its combination with nutrient-limitation are novel environmental stressors for induction of triacylglycerol accumulation in cells of Chlorella kessleri

    PubMed Central

    Hirai, Kazuho; Hayashi, Taihei; Hasegawa, Yuri; Sato, Atsushi; Tsuzuki, Mikio; Sato, Norihiro

    2016-01-01

    Triacylglycerols of oleaginous algae are promising for production of food oils and biodiesel fuel. Air-drying of cells induces triacylglycerol accumulation in a freshwater green alga, Chlorella kessleri, therefore, it seems that dehydration, i.e., intracellular hyperosmosis, and/or nutrient-limitation are key stressors. We explored this possibility in liquid-culturing C. kessleri cells. Strong hyperosmosis with 0.9 M sorbitol or 0.45 M NaCl for two days caused cells to increase the triacylglycerol content in total lipids from 1.5 to 48.5 and 75.3 mol%, respectively, on a fatty acid basis, whereas nutrient-limitation caused its accumulation to 41.4 mol%. Even weak hyperosmosis with 0.3 M sorbitol or 0.15 M NaCl, when nutrient-limitation was simultaneously imposed, induced triacylglycerol accumulation to 61.9 and 65.7 mol%, respectively. Furthermore, culturing in three-fold diluted seawater, the chemical composition of which resembled that of the medium for the combinatory stress, enabled the cells to accumulate triacylglycerol up to 24.7 weight% of dry cells in only three days. Consequently, it was found that hyperosmosis is a novel stressor for triacylglycerol accumulation, and that weak hyperosmosis, together with nutrient-limitation, exerts a strong stimulating effect on triacylglycerol accumulation. A similar combinatory stress would contribute to the triacylglycerol accumulation in air-dried C. kessleri cells. PMID:27184595

  19. The role of algae in mine drainage bioremediation

    SciTech Connect

    Davison, J. )

    1990-06-01

    The effect of mine drainage effluent on aquatic ecosystems has been abundantly documented and remediation efforts to data have always been costly and temporary at best. Bioremediation, using natural environmental microbes, to treat acid mine drainage has shown great promise as an affordable, permanent treatment. At Lambda, we used mixatrophic cultures of bacteria, algae, protozoans and fungal groups on four different jobs and it has proven effective. The role of two particular algal groups, the Euglena mutabilis and the Ochramonas sp. are particularly of phycological interest.

  20. A lack of parasitic reduction in the obligate parasitic green alga Helicosporidium.

    PubMed

    Pombert, Jean-François; Blouin, Nicolas Achille; Lane, Chris; Boucias, Drion; Keeling, Patrick J

    2014-05-01

    The evolution of an obligate parasitic lifestyle is often associated with genomic reduction, in particular with the loss of functions associated with increasing host-dependence. This is evident in many parasites, but perhaps the most extreme transitions are from free-living autotrophic algae to obligate parasites. The best-known examples of this are the apicomplexans such as Plasmodium, which evolved from algae with red secondary plastids. However, an analogous transition also took place independently in the Helicosporidia, where an obligate parasite of animals with an intracellular infection mechanism evolved from algae with green primary plastids. We characterised the nuclear genome of Helicosporidium to compare its transition to parasitism with that of apicomplexans. The Helicosporidium genome is small and compact, even by comparison with the relatively small genomes of the closely related green algae Chlorella and Coccomyxa, but at the functional level we find almost no evidence for reduction. Nearly all ancestral metabolic functions are retained, with the single major exception of photosynthesis, and even here reduction is not complete. The great majority of genes for light-harvesting complexes, photosystems, and pigment biosynthesis have been lost, but those for other photosynthesis-related functions, such as Calvin cycle, are retained. Rather than loss of whole function categories, the predominant reductive force in the Helicosporidium genome is a contraction of gene family complexity, but even here most losses affect families associated with genome maintenance and expression, not functions associated with host-dependence. Other gene families appear to have expanded in response to parasitism, in particular chitinases, including those predicted to digest the chitinous barriers of the insect host or remodel the cell wall of Helicosporidium. Overall, the Helicosporidium genome presents a fascinating picture of the early stages of a transition from free