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Sample records for alga scenedesmus 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. 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

  3. 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

  4. 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

  5. Effect of temperature on ammonium removal in Scenedesmus sp.

    PubMed

    Ruiz-Martínez, A; Serralta, J; Seco, A; Ferrer, J

    2015-09-01

    The effect of temperature on microalgal ammonium uptake was investigated by carrying out four batch experiments in which a mixed culture of microalgae, composed mainly of Scenedesmus sp., was cultivated under different temperatures within the usual temperature working range in Mediterranean climate (15-34 °C). Ammonium removal rates increased with temperature up to 26 °C and stabilized thereafter. Ratkowsky and Cardinal temperatures models successfully reproduced the experimental data. Optimum (31.3 °C), minimum (8.8 °C) and maximum (46.1 °C) temperatures for ammonium removal by Scenedesmus sp. under the studied conditions were obtained as model parameters. These temperature-related parameters constitute very useful information for designing and operating wastewater treatment systems using these microalgae. PMID:26027902

  6. Effects of acid stress on Scenedesmus quadricauda (chlorophyta) and Anabaena sp. (cyanophyta)

    SciTech Connect

    Hadden-Carter, P.J.

    1984-01-01

    The effects of pH in conjunction with light and temperature on growth of Scenedesmus quadricauda (Chlorophyta) and Anabaena sp. (Cyanophyta) were examined in culture. Decreasing pH from 7 to 3 inhibited growth, more so in the blue-green alga. Effects were greatly influenced by light and temperature. Above a critical level (pH4 with the blue-green, pH 3 with the green) both algae recovered when acid stress was removed; post-acidification growth rates varied inversely with pH for the green alga and directly for the blue-green. Two sheathed blue-green algae (Lyngbya and Gleocapsa) grew below pH 6, while two unsheathed blue-green algae (Anabaena and Oscillatoria) did not. Cell dimensions of both S. quadricaude and Anabaena sp. generally increased as pH declined; the green alga was the more plastic of the two. Acid stress significantly decreased photosynthetic rate in S. quadricauda but did not for Anabaena sp. Respiratory rates were not significantly related to pH for either alga. Chlorophyll a per cell was higher than controls (pH 7) at pH 5 and 6 in Anabaena sp. and at pH 4 through 6 for S. quadricauda. Both cell division and total culture biomass declined with pH. When grown in mixed culture, the green alga usually predominated at pH 4 and often at pH 5; the blue-green was favored at lower light intensities and higher temperatures. In no instance did one alga stimulate growth of the other, although mutual inhibition occurred in several instances.

  7. The mechanism of lipids extraction from wet microalgae Scenedesmus sp. by ionic liquid assisted subcritical water

    NASA Astrophysics Data System (ADS)

    Yu, Zhuanni; Chen, Xiaolin; Xia, Shuwei

    2016-06-01

    In this paper, the total sugar concentration, protein concentration, lipid yield and morphology characteristics of the algae residue were determined to explain the mechanism of lipids extraction from wet microalgae Scenedesmus sp. by ionic liquid assisted subcritical water. The results showed similar variation for the sugar, protein and lipid. However, the total sugar was more similar to lipids yield, so the results showed that the reaction between ionic liquid and cellulose and hemicellulose in cell wall was the most important step which determined the lipids extration directly. And the total sugar variation may be representing the lipids yield. For later lipids extraction, we can determine the total sugar concentration to predict the extraction end product.

  8. Effect of cadmium on cellular viability in two species of microalgae (Scenedesmus sp. and Dunaliella viridis).

    PubMed

    Marcano, Letty Beatriz C; Carruyo, Ingrid M; Montiel, Xiomara M; Morales, Carolina B; de Soto, Patricia Moreno

    2009-07-01

    We determined the effect of several concentrations of cadmium (0, 5, 10, and 20 microg/l) on cellular viability in the microalgae Scenedesmus sp. and Dunaliella viridis, by measuring growth at 0, 24, 48, 72, and 96 h and pigment production at 10 days. Algae were obtained from the Nonvascular Plant Laboratory collection, in the Facultad Experimental de Ciencias, Universidad del Zulia, Venezuela. Growth was measured by cellular counting, while pigment content was evaluated using conventional spectrophotometric techniques. Growth of both species decreased in the exposed cultures comparing with the control, but its behavior was similar, because in both control and exposed cultures, its was observed an adaptive phase in the first hours, as well as a growth phase after 72 h. Cadmium concentrations above 10 microg/l produced an adverse effect on pigment production, depending on the concentration and/or exhibition time. However, even though cadmium inhibited growth and pigment production, levels of both parameters indicated cellular viability, demonstrating the adaptability of the algae cultures when they were exposed to the metal. PMID:19172231

  9. Supercritical fluid extraction and characterization of lipids from algae Scenedesmus obliquus

    NASA Technical Reports Server (NTRS)

    Choi, K. J.; Nakhost, Z.; Krukonis, V. J.; Karel, M.

    1987-01-01

    Lipids were extracted from a protein concentrate of green algae (Scenedesmus obliquus), using a one-step supercritical carbon dioxide extraction procedure in presence of ethanol as an entrainer, and were characterized. The compositions of neutral lipids, glycolipids, and phospholipids, separated into individual components by column, thin-layer, and gas-liquid chromatography procedures, are presented. Fatty acid composition patterns indicated that the major fatty acids were 16:0, 16:1, 16:2, 16:3, 16:4, 18:1, 18:2, and 18:3. The lipids of S. obliquus were found to contain relatively high concentrations of polyunsaturated fatty acids and essential fatty acids.

  10. The Growth of Monoraphidium sp. and Scenedesmus sp. Cells in the Presence of Thorium

    PubMed Central

    de Queiroz, Juliana Cristina; Ferreira, Ana Cristina de Melo; da Costa, Antonio Carlos Augusto

    2012-01-01

    Toxicity of thorium by Monoraphidium sp. and Scenedesmus sp. was studied. Microalgal cultures were inoculated in ASM-1 medium in presence and absence of thorium. Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with software. The toxicity of thorium over the species was observed for concentrations over 50.0 mg/L. After 30 days, Monoraphidium cells decreased their concentration from 4.23 × 106 to 4.27 × 105 and 8.57 × 105 cells/mL, in the presence of 50.0 and 100.0 mg/L of thorium, respectively. Scenedesmus sp. cells were more resistant to thorium: for an initial cell concentration of 7.65 × 104 cells/mL it was observed a change to 5.25 × 105 and 5.12 × 105 cells/mL, in the presence of thorium at 50.0 and 100.0 mg/L, respectively. This is an indication that low concentrations of the radionuclide favored the growth, and that Scenedesmus cells are more resistant to thorium than Monoraphidium cells. The software used for comparison with direct count method proved to be useful for the improvement of accuracy of the results obtained, a decrease in the uncertainty and allowed recording of the data. The presence of thorium suggests that low concentrations have a positive effect on the growth, due to the presence of the nitrate, indicating its potential for ecotoxicological studies. PMID:22649297

  11. A Green Algae Mixture of Scenedesmus and Schroederiella Attenuates Obesity-Linked Metabolic Syndrome in Rats

    PubMed Central

    Kumar, Senthil Arun; Magnusson, Marie; Ward, Leigh C.; Paul, Nicholas A.; Brown, Lindsay

    2015-01-01

    This study investigated the responses to a green algae mixture of Scenedesmus dimorphus and Schroederiella apiculata (SC) containing protein (46.1% of dry algae), insoluble fibre (19.6% of dry algae), minerals (3.7% of dry algae) and omega-3 fatty acids (2.8% of dry algae) as a dietary intervention in a high carbohydrate, high fat diet-induced metabolic syndrome model in four groups of male Wistar rats. Two groups were fed with a corn starch diet containing 68% carbohydrates as polysaccharides, while the other two groups were fed a diet high in simple carbohydrates (fructose and sucrose in food, 25% fructose in drinking water, total 68%) and fats (saturated and trans fats from beef tallow, total 24%). High carbohydrate, high fat-fed rats showed visceral obesity with hypertension, insulin resistance, cardiovascular remodelling, and nonalcoholic fatty liver disease. SC supplementation (5% of food) lowered total body and abdominal fat mass, increased lean mass, and attenuated hypertension, impaired glucose and insulin tolerance, endothelial dysfunction, infiltration of inflammatory cells into heart and liver, fibrosis, increased cardiac stiffness, and nonalcoholic fatty liver disease in the high carbohydrate, high fat diet-fed rats. This study suggests that the insoluble fibre or protein in SC helps reverse diet-induced metabolic syndrome. PMID:25875119

  12. A green algae mixture of Scenedesmus and Schroederiella attenuates obesity-linked metabolic syndrome in rats.

    PubMed

    Kumar, Senthil Arun; Magnusson, Marie; Ward, Leigh C; Paul, Nicholas A; Brown, Lindsay

    2015-04-01

    This study investigated the responses to a green algae mixture of Scenedesmus dimorphus and Schroederiella apiculata (SC) containing protein (46.1% of dry algae), insoluble fibre (19.6% of dry algae), minerals (3.7% of dry algae) and omega-3 fatty acids (2.8% of dry algae) as a dietary intervention in a high carbohydrate, high fat diet-induced metabolic syndrome model in four groups of male Wistar rats. Two groups were fed with a corn starch diet containing 68% carbohydrates as polysaccharides, while the other two groups were fed a diet high in simple carbohydrates (fructose and sucrose in food, 25% fructose in drinking water, total 68%) and fats (saturated and trans fats from beef tallow, total 24%). High carbohydrate, high fat-fed rats showed visceral obesity with hypertension, insulin resistance, cardiovascular remodelling, and nonalcoholic fatty liver disease. SC supplementation (5% of food) lowered total body and abdominal fat mass, increased lean mass, and attenuated hypertension, impaired glucose and insulin tolerance, endothelial dysfunction, infiltration of inflammatory cells into heart and liver, fibrosis, increased cardiac stiffness, and nonalcoholic fatty liver disease in the high carbohydrate, high fat diet-fed rats. This study suggests that the insoluble fibre or protein in SC helps reverse diet-induced metabolic syndrome. PMID:25875119

  13. Bioenergetic Strategy for the Biodegradation of p-Cresol by the Unicellular Green Alga Scenedesmus obliquus

    PubMed Central

    Papazi, Aikaterini; Assimakopoulos, Konstantinos; Kotzabasis, Kiriakos

    2012-01-01

    Cultures from the unicellular green alga Scenedesmus obliquus biodegrade the toxic p-cresol (4-methylphenol) and use it as alternative carbon/energy source. The biodegradation procedure of p-cresol seems to be a two-step process. HPLC analyses indicate that the split of the methyl group (first step) that is possibly converted to methanol (increased methanol concentration in the growth medium), leading, according to our previous work, to changes in the molecular structure and function of the photosynthetic apparatus and therefore to microalgal biomass increase. The second step is the fission of the intermediately produced phenol. A higher p-cresol concentration results in a higher p-cresol biodegradation rate and a lower total p-cresol biodegradability. The first biodegradation step seems to be the most decisive for the effectiveness of the process, because methanol offers energy for the further biodegradation reactions. The absence of LHCII from the Scenedesmus mutant wt-lhc stopped the methanol effect and significantly reduced the p-cresol biodegradation (only 9%). The present contribution deals with an energy distribution between microalgal growth and p-cresol biodegradation, activated by p-cresol concentration. The simultaneous biomass increase with the detoxification of a toxic phenolic compound (p-cresol) could be a significant biotechnological aspect for further applications. PMID:23251641

  14. Accumulation of dieldrin in an alga (Scenedesmus obliquus), Daphnia magna, and the guppy (Poecilia reticulata)

    USGS Publications Warehouse

    Reinert, Robert E.

    1972-01-01

    Scenedesmus obliquus, Daphnia magna, and Poecilia reticulata accumulated dieldrin directly from water; average concentration factors (concentration in organism, dry weight, divided by concentration in water) were 1282 for the alga, 13,954 for D. magna, and 49,307 (estimated) for the guppy. The amount accumulated by each species at equilibrium (after about 1.5, 3-4, and 18 days, respectively) was directly proportional to the concentration of dieldrin in the water. Daphnia magna and guppies accumulated more dieldrin from water than from food that had been exposed to similar concentrations in water. When guppies were fed equal daily rations of D. magna containing different concentrations of insecticide, the amounts of dieldrin accumulated by the fish were directly proportional to the concentration in D. magna; when two lots of guppies were fed different quantities of D. magna (10 and 20 organisms per day) containing identical concentrations of dieldrin, however, the amounts accumulated did not differ substantially.

  15. Effects of artificial sweeteners on metal bioconcentration and toxicity on a green algae Scenedesmus obliquus.

    PubMed

    Hu, Hongwei; Deng, Yuanyuan; Fan, Yunfei; Zhang, Pengfei; Sun, Hongwen; Gan, Zhiwei; Zhu, Hongkai; Yao, Yiming

    2016-05-01

    The ecotoxicity of heavy metals depends much on their speciation, which is influenced by other co-existing substances having chelating capacity. In the present study, the toxic effects of Cd(2+) and Cu(2+) on a green algae Scenedesmus obliquus were examined in the presence of two artificial sweeteners (ASs), acesulfame (ACE) and sucralose (SUC) by comparing the cell specific growth rate μ and pulse-amplitude-modulated (PAM) parameters (maximal photosystem II photochemical efficiency Fv/Fm, actual photochemical efficiency Yield, and non-photochemical quenching NPQ) of the algae over a 96-h period. Simultaneously, the bioconcentration of the metals by the algal cells in the presence of the ASs was measured. The presence of ACE enhanced the growth of S. obliquus and promoted the bioconcentration of Cd(2+) in S. obliquus, while the impacts of SUC were not significant. Meanwhile, EC50 values of Cd(2+) on the growth of S. obliquus increased from 0.42 mg/L to 0.54 mg/L and 0.48 mg/L with the addition of 1.0 mg/L ACE and SUC, respectively. As for Cu(2+), EC50 values increased from 0.13 mg/L to 0.17 mg/L and 0.15 mg/L with the addition of 1.0 mg/L ACE and SUC, respectively. In summary, the two ASs reduced the toxicity of the metals on the algae, with ACE showing greater effect than SUC. Although not as sensitive as the cell specific growth rate, PAM parameters could disclose the mechanisms involved in metal toxicity at subcellular levels. This study provides the first evidence for the possible impact of ASs on the ecotoxicity of heavy metals. PMID:26915590

  16. Toxicity evaluation of pharmaceutical wastewaters using the alga Scenedesmus obliquus and the bacterium Vibrio fischeri.

    PubMed

    Yu, Xin; Zuo, Jiane; Tang, Xinyao; Li, Ruixia; Li, Zaixing; Zhang, Fei

    2014-02-15

    The toxicity of pharmaceutical wastewaters has recently been the focus of the public in China. This study aimed to evaluate the conventional pollution parameters and toxicities of different raw and treated pharmaceutical wastewaters to algae Scenedesmus obliquus and bacteria Vibrio fischeri. Wastewater samples were collected from 16 pharmaceutical wastewater treatment plants in China. The results of the conventional parameters analysis indicated that the total suspended solids, chemical oxygen demand (COD), ammonia (NH3-N), and total phosphorus (TP) were largely removed after treatment. Pharmaceutical effluents were mainly polluted with organics and phosphorus as indicated by the average COD (388 mg/L) and TP (3.16 mg/L) concentrations. The toxicity test results indicated that the influent samples were toxic to both test species. Although the toxicities could be remarkably reduced after treatment, 10 out of the 16 effluent samples exceeded the acute toxicity discharge limit of the Chinese national standards. Spearman rank correlation coefficients indicated a significantly positive correlation between the toxicity values of S. obliquus and V. fischeri. Compared with S. obliquus, V. fischeri detected more pharmaceutical effluent samples with toxicities. Meanwhile, the toxicity indicators were significantly and positively correlated with the COD and NH3-N concentrations based on a Spearman rank correlation analysis. PMID:24374566

  17. Bicarbonate supplementation enhanced biofuel production potential as well as nutritional stress mitigation in the microalgae Scenedesmus sp. CCNM 1077.

    PubMed

    Pancha, Imran; Chokshi, Kaumeel; Ghosh, Tonmoy; Paliwal, Chetan; Maurya, Rahulkumar; Mishra, Sandhya

    2015-10-01

    The aim of the present study was to find out the optimum sodium bicarbonate concentration to produce higher biomass with higher lipid and carbohydrate contents in microalgae Scenedesmus sp. CCNM 1077. The role of bicarbonate supplementation under different nutritional starvation conditions was also evaluated. The results clearly indicate that 0.6 g/L sodium bicarbonate was optimum concentration resulting in 20.91% total lipid and 25.56% carbohydrate along with 23% increase in biomass production compared to normal growth condition. Addition of sodium bicarbonate increased the activity of nutrient assimilatory enzymes, biomass, lipid and carbohydrate contents under different nutritional starvation conditions. Nitrogen starvation with bicarbonate supplementation resulted in 54.03% carbohydrate and 34.44% total lipid content in microalgae Scenedesmus sp. CCNM 1077. These findings show application of bicarbonate grown microalgae Scenedesmus sp. CCNM 1077 as a promising feedstock for biodiesel and bioethanol production. PMID:26142998

  18. High Yields of Hydrogen Production Induced by Meta-Substituted Dichlorophenols Biodegradation from the Green Alga Scenedesmus obliquus

    PubMed Central

    Papazi, Aikaterini; Andronis, Efthimios; Ioannidis, Nikolaos E.; Chaniotakis, Nikolaos; Kotzabasis, Kiriakos

    2012-01-01

    Hydrogen is a highly promising energy source with important social and economic implications. The ability of green algae to produce photosynthetic hydrogen under anaerobic conditions has been known for years. However, until today the yield of production has been very low, limiting an industrial scale use. In the present paper, 73 years after the first report on H2-production from green algae, we present a combinational biological system where the biodegradation procedure of one meta-substituted dichlorophenol (m-dcp) is the key element for maintaining continuous and high rate H2-production (>100 times higher than previously reported) in chloroplasts and mitochondria of the green alga Scenedesmus obliquus. In particular, we report that reduced m-dcps (biodegradation intermediates) mimic endogenous electron and proton carriers in chloroplasts and mitochondria, inhibit Photosystem II (PSII) activity (and therefore O2 production) and enhance Photosystem I (PSI) and hydrogenase activity. In addition, we show that there are some indications for hydrogen production from sources other than chloroplasts in Scenedesmus obliquus. The regulation of these multistage and highly evolved redox pathways leads to high yields of hydrogen production and paves the way for an efficient application to industrial scale use, utilizing simple energy sources and one meta-substituted dichlorophenol as regulating elements. PMID:23145057

  19. Effect of organic loading rate on anaerobic digestion of thermally pretreated Scenedesmus sp. biomass.

    PubMed

    González-Fernández, C; Sialve, B; Bernet, N; Steyer, J P

    2013-02-01

    Biogas production is one of the means to produce a biofuel from microalgae. Biomass consisting mainly of Scenedesmus sp. was thermally pretreated and optimum pretreatment length (1 h) and temperature (90 °C) was selected. Different chemical composition among batches stored at 4 °C for different lengths of time resulted in organic matter hydrolysis percentages ranging from 3% to 7%. The lower percentages were attributed to cell wall thickening observed during storage for 45 days. The different hydrolysis percentages did not cause differences in anaerobic digestion. Pretreatment of Scenedesmus sp. at 90 °C for 1h increased methane production 2.9 and 3.4-fold at organic loading rates (OLR) of 1 and 2.5 kg COD m(-3) day(-1), respectively. Regardless the OLR, inhibition caused by organic overloading or ammonia toxicity were not detected. Despite enhanced methane production, anaerobic biodegradability of this biomass remained low (32%). Therefore, this microalga is not a suitable feedstock for biogas production unless a more suitable pretreatment can be found. PMID:23247149

  20. Optimization of Medium Using Response Surface Methodology for Lipid Production by Scenedesmus sp.

    PubMed Central

    Yang, Fangfang; Long, Lijuan; Sun, Xiumei; Wu, Hualian; Li, Tao; Xiang, Wenzhou

    2014-01-01

    Lipid production is an important indicator for assessing microalgal species for biodiesel production. In this work, the effects of medium composition on lipid production by Scenedesmus sp. were investigated using the response surface methodology. The results of a Plackett–Burman design experiment revealed that NaHCO3, NaH2PO4·2H2O and NaNO3 were three factors significantly influencing lipid production, which were further optimized by a Box–Behnken design. The optimal medium was found to contain 3.07 g L−1 NaHCO3, 15.49 mg L−1 NaH2PO4·2H2O and 803.21 mg L−1 NaNO3. Using the optimal conditions previously determined, the lipid production (304.02 mg·L−1) increased 54.64% more than that using the initial medium, which agreed well with the predicted value 309.50 mg L−1. Additionally, lipid analysis found that palmitic acid (C16:0) and oleic acid (C18:1) dominantly constituted the algal fatty acids (about 60% of the total fatty acids) and a much higher content of neutral lipid accounted for 82.32% of total lipids, which strongly proved that Scenedesmus sp. is a very promising feedstock for biodiesel production. PMID:24663113

  1. Fossil Scenedesmus (Chlorococcales) from the Raton Formation, Colorado and New Mexico, U.S.A.

    USGS Publications Warehouse

    Farley, Fleming R.

    1989-01-01

    Fossilized coenobia of the alga Scenedesmus (Chlorococcales) were recovered in palynomorph assemblages from a lower Paleocene mudstone in the Upper Cretaceous and Paleocene Raton Formation of Colorado and New Mexico. This is the first description of fossil Scenedesmus from Tertiary rocks. Two species, Scenedesmus tschudyi sp. nov. and Scenedesmus hanleyi sp. nov., are present in the assemblages. Coenobia of S. tschudyi sp. nov. are characterized by lunate terminal cells and fusiform median cells. As in species of modern Scenedesmus, coenobia of S. tschudyi sp. nov. occur with four or eight cells. Coenobia of S. hanleyi sp. nov. have four oval cells and are smaller than coenobia of S. tschudyi sp. nov. Fossil coenobia of Scenedesmus co-occur with the fossil alga Pediastrum in Raton Formation mudstones. Because these genera co-occur in modern lakes and ponds, the co-occurrence of fossil Scenedesmus and Pediastrum in ancient nonmarine rocks is interpreted to indicate deposition of sediment in freshwater lakes and ponds. ?? 1989.

  2. Effect propagation in a toxicokinetic/toxicodynamic model explains delayed effects on the growth of unicellular green algae Scenedesmus vacuolatus.

    PubMed

    Vogs, Carolina; Bandow, Nicole; Altenburger, Rolf

    2013-04-01

    Ecotoxicological standard tests assess toxic effects by exposing an organism to high concentrations over defined periods of time. To evaluate toxicity under field conditions such as fluctuating and pulsed exposures, process-based toxicokinetic/toxicodynamic (TK/TD) models may be used for extrapolation from the existing evidence. A TK/TD model was developed that simulates the effect on growth of the green algae Scenedesmus vacuolatus continuously exposed to the model chemicals norflurazon, triclosan, and N-phenyl-2-naphthylamine. A pharmacological time-response model describing the effects of anticancer treatments on cancer cell growth was adapted and modified to model the affected growth of synchronized algae cells. The TK/TD model simulates the temporal effect course by linking the ambient concentration of a chemical to the observable adverse effect via an internal concentration and a sequence of biological events in the organism. The parameters of the toxicodynamic model are related to the growth characteristics of algae cells, a no effect concentration, the chemical efficacy as well as the ability of recovery and repair, and the delay during damage propagation. The TK/TD model fits well to the observed algae growth. The effect propagation through cumulative cell damage explained the observed delayed responses better than just the toxicokinetics. The TK/TD model could facilitate the link between several effect levels within damage propagation, which prospectively may be helpful to model adverse outcome pathways and time-dependent mixture effects. PMID:23359135

  3. Role of Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 as Bioindicators and Immobilizers of Chromium in a Contaminated Natural Environment

    PubMed Central

    Millach, Laia; Solé, Antoni; Esteve, Isabel

    2015-01-01

    The aim of this work was to study the potential of the two phototrophic microorganisms, both isolated from Ebro Delta microbial mats, to be used as bioindicators and immobilizers of chromium. The results obtained indicated that (i) the Minimum Metal Concentration (MMC) significantly affecting Chlorophyll a intensity in Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 was 0.25 µM and 0.75 µM, respectively, these values being lower than those established by current legislation, and (ii) Scenedesmus sp. DE2009 was able to immobilize chromium externally in extracellular polymeric substances (EPS) and intracellularly in polyphosphate (PP) inclusions. Additionally, this microorganism maintained high viability, including at 500 µM. Based on these results, we postulate that Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 are good chromium-indicators of cytotoxicity and, further, that Scenedesmus sp. DE2009 plays an important role in immobilizing this metal in a contaminated natural environment. PMID:26167488

  4. Indirect aluminum toxicity to the green alga Scenedesmus through increased cupric ion activity

    SciTech Connect

    Rueter, J.G. Jr.; O'Reilly, K.T.; Petersen, R.R.

    1987-05-01

    Additions of aluminum and copper to chemically defined media resulted in inhibition of growth of Scenedesmus and of alkaline phosphatase activity. The alkaline phosphatase activity was assayed both on commercially available purified enzyme from bacteria and on the enzyme present in whole Scenedesmus cells. The effect of metal additions was compared to the total aluminum added and to the computed free ion activities for both copper and aluminum. In all three systems (algal growth, purified enzyme, and algal enzyme) the observed toxicity with increased total aluminum was mostly due to an increase in cupric ion activity. The algal growth response was affected for the range of cupric ion activities from 10/sup -6/ to 10/sup -12/. The toxic dose response of aluminum was largely due to indirect competitive effects of Al in the medium that displaced copper from the chelator. 33 references, 4 figures.

  5. Algae (Microcystis and Scenedesmus) absorption spectra and its application on Chlorophyll a retrieval

    NASA Astrophysics Data System (ADS)

    Wu, Di; Chen, Maosi; Wang, Qiao; Gao, Wei

    2013-12-01

    Blue algae and green algae are the dominant phytoplankton groups that contribute to the eutrophication and the water bloom in inland water of China. The absorption coefficients (spectra) of the algae, which do not change with its intrinsic optical characteristics and the observation geometry, are strictly additive quantities. The characteristics of the absorption spectra of the two algae are presented. The pure blue algae and the pure green algae cultured in the laboratory environment are diluted and mixed at ten volume ratios. The Quantitative Filter Technique was applied to measure their absorption spectra. The "hot-ethanol extraction" method was chosen to calculate their concentration of Chlorophyll a. The retrieval algorithm developed in this study extracts the mapping information between each individual alga and their Chlorophyll a concentration via Continuous Wavelet Transform, and retrieves the Chlorophyll a concentration of each alga in their mixture using a trust region optimizer. The results show that the retrieved and the measured Chlorophyll a concentrations of the blue algae and the green algae components in the ten mixture match well with the average relative error of 5.55%.

  6. 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.

  7. Metagenome changes in the mesophilic biogas-producing community during fermentation of the green alga Scenedesmus obliquus.

    PubMed

    Wirth, Roland; Lakatos, Gergely; Böjti, Tamás; Maróti, Gergely; Bagi, Zoltán; Kis, Mihály; Kovács, Attila; Ács, Norbert; Rákhely, Gábor; Kovács, Kornél L

    2015-12-10

    A microalgal biomass offers a potential alternative to the maize silage commonly used in biogas technology. In this study, photoautotrophically grown Scenedesmus obliquus was used as biogas substrate. This microalga has a low C/N ratio of 8.5 relative to the optimum 20-30. A significant increase in the ammonium ion content was not observed. The methane content of the biogas generated from Sc. obliquus proved to be higher than that from maize silage, but the specific biogas yield was lower. Semi-continuous steady biogas production lasted for 2 months. Because of the thick cell wall of Sc. obliquus, the biomass-degrading microorganisms require additional time to digest its biomass. The methane concentration in the biogas was also high, in co-digestion (i.e., 52-56%) as in alga-fed anaerobic digestion (i.e., 55-62%). These results may be related to the relative predominance of the order Clostridiales in co-digestion and to the more balanced C/N ratio of the mixed algal-maize biomass. Predominance of the order Methanosarcinales was observed in the domain Archaea, which supported the diversity of metabolic pathways in the process. PMID:26087313

  8. Lipid content and fatty acid composition of green algae Scenedesmus obliquus grown in a constant cell density apparatus

    NASA Technical Reports Server (NTRS)

    Choi, K. J.; Nakhost, Z.; Barzana, E.; Karel, M.

    1987-01-01

    The lipids of alga Scenedesmus obliquus grown under controlled conditions were separated and fractionated by column and thin-layer chromatography, and fatty acid composition of each lipid component was studied by gas-liquid chromatography (GLC). Total lipids were 11.17%, and neutral lipid, glycolipid and phospholipid fractions were 7.24%, 2.45% and 1.48% on a dry weight basis, respectively. The major neutral lipids were diglycerides, triglycerides, free sterols, hydrocarbons and sterol esters. The glycolipids were: monogalactosyl diglyceride, digalactosyl diglyceride, esterified sterol glycoside, and sterol glycoside. The phospholipids included: phosphatidyl choline, phosphatidyl glycerol and phosphatidyl ethanolamine. Fourteen fatty acids were identified in the four lipid fractions by GLC. The main fatty acids were C18:2, C16:0, C18:3(alpha), C18:1, C16:3, C16:1, and C16:4. Total unsaturated fatty acid and essential fatty acid compositions of the total algal lipids were 80% and 38%, respectively.

  9. Reduction in toxicity of wastewater from three wastewater treatment plants to alga (Scenedesmus obliquus) in northeast China.

    PubMed

    Zhang, Ying; Sun, Qing; Zhou, Jiti; Masunaga, Shigeki; Ma, Fang

    2015-09-01

    The toxicity of municipal wastewater to the receiving water bodies is still unknown, due to the lack of regulated toxicity based index for wastewater discharge in China. Our study aims at gaining insight into the acute toxic effects of local municipal wastewater on alga, Scenedesmus obliquus. Four endpoints, i.e. cell density, chlorophyll-A concentration, superoxide dismutase (SOD) activity and cell membrane integrity, of alga were analyzed to characterize the acute toxicity effects of wastewater from municipal wastewater treatment plants (WWTPs) with different treatment techniques: sequencing batch reactor (SBR), Linpor and conventional activated sludge. Influent and effluent from each treatment stage in these three WWTPs were sampled and evaluated for their acute toxicity. Our results showed that all three techniques can completely affect the algal chlorophyll-A synthesis stimulation effects of influent; the algal cell growth stimulation effect was only completely removed by the secondary treatment process in conventional activated sludge technique; toxic effects on cell membrane integrity of two influents from WWTPs with SBR and conventional activated sludge techniques were completely removed; the acute toxicity on SOD activity was partially reduced in SBR and conventional activated sludge techniques while not significantly reduced by Linpor system. As to the disinfection unit, NaClO disinfection enhanced wastewater toxicity dramatically while UV radiation had no remarkable influence on wastewater toxicity. Our results illustrated that SOD activity and chlorophyll-A synthesis were relatively sensitive to municipal wastewater toxicity. Our results would aid to understand the acute toxicity of municipal wastewater, as well as the toxicity removal by currently utilized treatment techniques in China. PMID:25996525

  10. Toxicity and accumulation of copper and cadmium in the alga Scenedesmus obliquus LH

    SciTech Connect

    Drbal, K.; Veber, K.; Zahradnik, J.

    1985-06-01

    The techniques of determination of toxic and inhibitory effects, and of measuring the kinetics of metal sorption, used by individual authors differ widely in basic parameters, especially in the experimental concentrations of algal suspensions and in methods of separation of algae. Some authors assume that the drop in the concentration of the metal in the solution, or its concentration in the biomass, are a measure of sorption of the metals by the algae. This is not entirely correct; our study led to this conclusion on the basis of measurement of inhibition of growth and sorption of copper and cadmium ions in dense algal suspensions in a photoautotrophic regime of an intensive culture, and comparison of disappearance of these ions from the solution in the absence of the algae.

  11. Physiology and methodology of chromium toxicity using alga Scenedesmus quadricauda as model object.

    PubMed

    Kováčik, Jozef; Babula, Petr; Hedbavny, Josef; Kryštofová, Olga; Provaznik, Ivo

    2015-02-01

    Physiological responses of Scenedesmus quadricauda to Cr(VI) and Cr(III) excess were studied in buffer with circumneutral pH (6.5). Total Cr content was similar in low (1 μM of both oxidation states) but higher in 10 μM Cr(VI) treatment and high accumulation potential was detected (80-82% and 41-65% in 1 and 10 μM treatments, respectively). Specific fluorescence indicator (6-((anthracen-9-yl) methyleneamino)-2H-chromen-2-one) confirmed partial reduction of Cr(VI) to Cr(III) under exposure conditions. Viability and chlorophyll autofluorescence were more depleted by Cr(VI) while Cr(III) stimulated increase in ROS and lipid peroxidation. Antioxidative enzyme activities showed significantly higher values in 10 μM treatments of both Cr oxidation states. Depletion of mitochondrial proteins was not reflected in alteration of total soluble proteins indicating sensitivity of this organelle to Cr and TTC test showed no clear oxidation state-related effect. In this view, "Cr(VI) is not more toxic than Cr(III)" at least for some parameters. Subsequent study with the application of 10 μM Cr(VI) confirmed that HEPES buffer is more suitable exposure solution for toxicological studied than water or inorganic salts (higher chlorophyll autofluorescence was observed) and pH 6.5 is more suitable than low or high pH (4.5 or 8.5) in terms of Cr uptake. Another known Cr(III) fluorescence indicator (naphthalimide-rhodamine) also confirmed partial reduction of Cr(VI) to Cr(III) at acidic pH but only traces were seen at alkaline pH. PMID:24972306

  12. Characterization of Photosystem II Activity and Heterogeneity during the Cell Cycle of the Green Alga Scenedesmus quadricauda1

    PubMed Central

    Kaftan, David; Meszaros, Tibor; Whitmarsh, John; Nedbal, Ladislav

    1999-01-01

    The photosynthetic activity of the green alga Scenedesmus quadricauda was investigated during synchronous growth in light/dark cycles. The rate of O2 evolution increased 2-fold during the first 3 to 4 h of the light period, remained high for the next 3 to 4 h, and then declined during the last half of the light period. During cell division, which occurred at the beginning of the dark period, the ability of the cells to evolve O2 was at a minimum. To determine if photosystem II (PSII) controls the photosynthetic capacity of the cells during the cell cycle we measured PSII activity and heterogeneity. Measurements of electron-transport activity revealed two populations of PSII, active centers that contribute to carbon reduction and inactive centers that do not. Measurements of PSII antenna sizes also revealed two populations, PSIIα and PSIIβ, which differ from one another by their antenna size. During the early light period the photosynthetic capacity of the cells doubled, the O2-evolving capacity of PSII was nearly constant, the proportion of PSIIβ centers decreased to nearly zero, and the proportion of inactive PSII centers remained constant. During the period of minimum photosynthetic activity 30% of the PSII centers were insensitive to the inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea, which may be related to reorganization of the thylakoid membrane. We conclude from these results that PSII does not limit the photosynthetic activity of the cells during the first half of the light period. However, the decline in photosynthetic activity observed during the last half of the light period can be accounted for by limited PSII activity. PMID:10364394

  13. Characterization and Screening of Native Scenedesmus sp. Isolates Suitable for Biofuel Feedstock.

    PubMed

    Gour, Rakesh Singh; Chawla, Aseem; Singh, Harvinder; Chauhan, Rajinder Singh; Kant, Anil

    2016-01-01

    In current study isolates of two native microalgae species were screened on the basis of growth kinetics and lipid accumulation potential. On the basis of data obtained on growth parameters and lipid accumulation, it is concluded that Scenedesmus dimorphus has better potential as biofuel feedstock. Two of the isolates of Scenedesmus dimorphus performed better than other isolates with respect to important growth parameters with lipid content of ~30% of dry biomass. Scenedesmus dimorphus was found to be more suitable as biodiesel feedstock candidate on the basis of cumulative occurrence of five important biodiesel fatty acids, relative occurrence of SFA (53.04%), MUFA (23.81%) and PUFA (19.69%), and more importantly that of oleic acid in its total lipids. The morphological observations using light and Scanning Electron Microscope and molecular characterization using amplified 18S rRNA gene sequences of microalgae species under study were also performed. Amplified 18S rRNA gene fragments of the microalgae species were sequenced, annotated at the NCBI website and phylogenetic analysis was done. We have published eight 18S rRNA gene sequences of microalgae species in NCBI GenBank. PMID:27195694

  14. Characterization and Screening of Native Scenedesmus sp. Isolates Suitable for Biofuel Feedstock

    PubMed Central

    Gour, Rakesh Singh; Chawla, Aseem; Singh, Harvinder; Chauhan, Rajinder Singh; Kant, Anil

    2016-01-01

    In current study isolates of two native microalgae species were screened on the basis of growth kinetics and lipid accumulation potential. On the basis of data obtained on growth parameters and lipid accumulation, it is concluded that Scenedesmus dimorphus has better potential as biofuel feedstock. Two of the isolates of Scenedesmus dimorphus performed better than other isolates with respect to important growth parameters with lipid content of ~30% of dry biomass. Scenedesmus dimorphus was found to be more suitable as biodiesel feedstock candidate on the basis of cumulative occurrence of five important biodiesel fatty acids, relative occurrence of SFA (53.04%), MUFA (23.81%) and PUFA (19.69%), and more importantly that of oleic acid in its total lipids. The morphological observations using light and Scanning Electron Microscope and molecular characterization using amplified 18S rRNA gene sequences of microalgae species under study were also performed. Amplified 18S rRNA gene fragments of the microalgae species were sequenced, annotated at the NCBI website and phylogenetic analysis was done. We have published eight 18S rRNA gene sequences of microalgae species in NCBI GenBank. PMID:27195694

  15. The cell-wall glycoproteins of the green alga Scenedesmus obliquus. The predominant cell-wall polypeptide of Scenedesmus obliquus is related to the cell-wall glycoprotein gp3 of Chlamydomonas reinhardtii.

    PubMed

    Voigt, Jürgen; Stolarczyk, Adam; Zych, Maria; Malec, Przemysław; Burczyk, Jan

    2014-02-01

    The green alga Scenedesmus obliquus contains a multilayered cell wall, ultrastructurally similar to that of Chlamydomonas reinhardtii, although its proportion of hydroxyproline is considerably lower. Therefore, we have investigated the polypeptide composition of the insoluble and the chaotrope-soluble wall fractions of S. obliquus. The polypeptide pattern of the chaotrope-soluble wall fraction was strongly modified by chemical deglycosylation with anhydrous hydrogen fluoride (HF) in pyridine indicating that most of these polypeptides are glycosylated. Polypeptide constituents of the chaotrope-soluble cell-wall fraction with apparent molecular masses of 240, 270, 265, and 135 kDa cross-reacted with a polyclonal antibody raised against the 100 kDa deglycosylation product of the C. reinhardtii cell-wall glycoprotein GP3B. Chemical deglycosylation of the chaotrope-soluble wall fraction resulted in a 135 kDa major polypeptide and a 106 kDa minor component reacting with the same antibody. This antibody recognized specific peptide epitopes of GP3B. When the insoluble wall fraction of S. obliquus was treated with anhydrous HF/pyridine, three polypeptides with apparent molecular masses of 144, 135, and 65 kDa were solubilized, which also occured in the deglycosylated chaotrope-soluble wall fraction. These findings indicate that theses glycoproteins are cross-linked to the insoluble wall fraction via HF-sensitive bonds. PMID:24388513

  16. 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.

  17. Anaerobic Co-Digestion of Microalgae Scenedesmus sp. and TWAS for Biomethane Production.

    PubMed

    Garoma, Temesgen; Nguyen, Don

    2016-01-01

    The paper investigated the feasibility of biomethane (bio-CH4) production from the anaerobic co-digestion of the microalgae Scenedesmus quadricauda (S. quadricauda) and thickened waste activated sludge (TWAS). The concept was tested in bench-scale anaerobic digesters by varying the proportions of volatile solids (VS) loading from S. quadricauda and TWAS and two critical operational parameters, temperature and alkalinity. The CH(4) production for the various S. quadricauda and TWAS proportions ranged from 234 to 318 mL/g of chemical oxygen demand (COD) digested and 329 to 530 mL/g of VS digested at 35 °C. The reductions in total solids (TS), COD, and VS ranged from 25 to 44%, 46 to 53%, and 40 to 53%, respectively. Temperature had a significant effect on CH(4) production, lower temperatures greatly reduced CH(4) production. No significant difference in CH(4) production was observed for experiments conducted at alkalinity levels of 70, 1630, and 3200 mg/L as CaCO(3). PMID:26803022

  18. Cultivation of freshwater microalga Scenedesmus sp. using a low-cost inorganic fertilizer for enhanced biomass and lipid yield.

    PubMed

    Nayak, Manoranjan; Thirunavoukkarasu, Manikkannan; Mohanty, Rama C

    2016-01-01

    The potential of an inorganic fertilizer as an alternative nutrient source for the cultivation of Scenedesmus sp. IMMTCC-6 was investigated. With a preliminary study at a shake-flask scale, the microalgae cultivation was scaled up in a photobioreactor containing an inorganic fertilizer medium. Microalgae cultured in a shake flask containing 0.1 g L(-1) of urea and 1.0 g L(-1) of NPK (Nitrogen: Phosphorus: Potassium) fertilizers showed a promising result in biomass productivity. During the scale-up study in a photobioreactor the specific growth rate (μ d(-1)), biomass yield (g L(-1)), and total biomass productivity (mg L(-1) d(-1)), was found to be 0.265, 1.19 and 66.1, respectively. The lipid yield (%) as per dry cell weight (DCW) and lipid productivity (mg L(-1) d(-1)) was found to be a maximum of 28.55 and 18.87, respectively, in a stationary phase of the microalgae growth. The fatty acids methyl ester profile was proven to be desirable for biodiesel production. PMID:26923125

  19. Acidogenic fermentation of Scenedesmus sp.-AMDD: Comparison of volatile fatty acids yields between mesophilic and thermophilic conditions.

    PubMed

    Gruhn, Marvin; Frigon, Jean-Claude; Guiot, Serge R

    2016-01-01

    This study compared the acidogenic fermentation of Scenedesmus sp.-AMDD at laboratory-scale, under mesophilic (35°C) and thermophilic conditions (55°C). Preliminary batch tests were performed to evaluate best conditions for volatile fatty acid (VFA) production from microalgal biomass, with respect to the inoculum, pH and nutrients. The use of bovine manure as inoculum, the operating pH of 4.5 and the addition of a nutrient mix, resulted in a high VFA production of up to 222mgg(-1) total volatile solid (TVS), with a butyrate share of 27%. Both digesters displayed similar hydrolytic activity with 0.38±0.02 and 0.42±0.03 g soluble chemical oxygen demand (COD)g(-1) TVS for the digesters operated at 35 and 55°C, respectively. Mesophilic conditions were more favorable for VFA production, which reached 171±5, compared to 88±12 mg soluble CODg(-1) TVS added under thermophilic conditions (94% more). It was shown that in both digesters, butyrate was the predominant VFA. PMID:26551650

  20. Minimizing the energy requirement of dewatering scenedesmus sp. by microfiltration: performance, costs, and feasibility.

    PubMed

    Gerardo, Michael L; Oatley-Radcliffe, Darren L; Lovitt, Robert W

    2014-01-01

    The harvesting of the microalgae Scenedesmus species using a 200 L pilot-scale microfiltration system was investigated and critically assessed. The energy requirement was determined and correlated to the different operating parameters, such as transmembrane pressure (ΔP), membrane area, temperature, and initial biomass concentration. A filtration model was developed and showed a strong correlation with experimental data up to 20.0 g of dry cell weight (DCW)/L. The non-optimized filtration system had an energy requirement of 2.23 kWh/m(3) with an associated cost of $0.282/kg of microalgae. The investigation into the influence of the operating parameters and scale-up effects showed that the energy requirement could be substantially reduced to 0.90 kWh/m(3) and $0.058/kg of microalgae harvested. Maintenance costs associated with cleaning were estimated to be 0.23 kWh or $0.029/batch of microalgae processed. Dependent upon the operating conditions, harvesting may represent 6-45% of the energy embedded in the microalgae with a carbon footprint of 0.74-1.67 kg of CO2/kg of microalgae. Microfiltration was demonstrated to be a feasible microalgae harvesting technology allowing for more than 99% volume reduction. The energy requirement and associated carbon footprint of microalgae harvesting reported here do not forfeit the need for an industrial-scale study; however, the information provided presents a more realistic approximation than the literature reported to date. PMID:24341825

  1. Evaluation of novel thermo-resistant Micractinium and Scenedesmus sp. for efficient biomass and lipid production under different temperature and nutrient regimes.

    PubMed

    Sonmez, Cagla; Elcin, Evrim; Akın, Dilan; Oktem, Huseyin Avni; Yucel, Meral

    2016-07-01

    Despite the vast interest in microalgae as feedstock for biodiesel production, relatively few studies examined their response to diurnal temperature fluctuation. Here, we describe biomass and lipid productivities and fatty acid profiles of thermo-resistant Micractinium sp. and Scenedesmus sp. grown in batch cultures in a laboratory set-up that mimics a typically warm summer day in Central Anatolia with a 16-h light temperature of 30°C and 8-h dark temperature of 16°C (30°C (day)/16°C (night)). Both strains can survive a temperature range of 10-50°C. We found the lipid productivities of Micractinium sp. and Scenedesmus sp. as 30/21mgL(-1)d(-1) and 6/7mgL(-1)d(-1), respectively during the 30°C (day)/16°C (night) cycle. Saturated fatty acid content increased with increasing temperature. Additionally, we cultured Micractinium sp. under Nitrogen (N) and Phosphorus (P) limiting conditions. Highest lipid productivity of 85.4±2mgL(-1)d(-1) was obtained under P-depletion during exponential growth phase. Oleic acid amount also increased eight fold during P-deplete. PMID:27035473

  2. Phycoremediation of Tannery Wastewater Using Microalgae Scenedesmus Species.

    PubMed

    Ajayan, Kayil Veedu; Selvaraju, Muthusamy; Unnikannan, Pachikaran; Sruthi, Palliyath

    2015-01-01

    A number of microalgae species are efficient in removing toxicants from wastewater. Many of these potential species are a promising, eco-friendly, and sustainable option for tertiary wastewater treatment with a possible advantage of improving the economics of microalgae cultivation for biofuel production. The present study deals with the phycoremediation of tannery wastewater (TWW) using Scenedesmus sp. isolated from a local habitat. The test species was grown in TWW under laboratory conditions and harvested on the 12th day. The results revealed that the algal biomass during the growth period not only reduced the pollution load of heavy metals (Cr-81.2-96%, Cu-73.2-98%, Pb-75-98% and Zn-65-98%) but also the nutrients (NO3 >44.3% and PO4 >95%). Fourier Transform Infrared (FTIR) spectrums of Scenedesmus sp. biomass revealed the involvement of hydroxyl amino, carboxylic and carbonyl groups. The scanning electron micrograph (SEM) and Energy Dispersive X-ray Spectroscopic analysis (EDS) revealed the surface texture, morphology and element distribution of the biosorbent. Furthermore, the wastewater generated during wet-blue tanning process can support dense population of Scenedesmus sp., making it a potential growth medium for biomass production of the test alga for phycoremediation of toxicants in tannery wastewaters. PMID:25580934

  3. Effect of scenedesmus acuminatus green algae extracts on the development of Candida lipolytic yeast in gas condensate-containing media

    NASA Technical Reports Server (NTRS)

    Bilmes, B. I.; Kasymova, G. A.; Runov, V. I.; Karavayeva, N. N.

    1980-01-01

    Data are given of a comparative study of the growth and development as well as the characteristics of the biomass of the C. Lipolytica yeast according to the content of raw protein, protein, lipids, vitamins in the B group, and residual hydrocarbons during growth in media with de-aromatized gas-condensate FNZ as the carbon source with aqueous and alcohol extracts of S. acuminatus as the biostimulants. It is shown that the decoction and aqueous extract of green algae has the most intensive stimulating effect on the yeast growth. When a decoction of algae is added to the medium, the content of residual hydrocarbons in the biomass of C. lipolytica yeast is reduced by 4%; the quantity of protein, lipids, thamine and inositol with replacement of the yeast autolysate by the decoction of algae is altered little.

  4. The effect of light color on the nucleocytoplasmic and chloroplast cycle of the green chlorococcal alga Scenedesmus obliquus.

    PubMed

    Cepák, V; Pribyl, P; Vítová, M

    2006-01-01

    The color of light (white, red, blue, and green) had a significant effect on the growth and reproductive processes (both in the nucleocytoplasmic and chloroplast compartment of the cells) in synchronous cultures of Scenedesmus obliquus. This effect decreased in the order red > white > blue > green. In the same order, the light phase of the cell cycle (time when first autospores started to be released) was prolonged. The length of dark phase (time when 100 % of daughters were allowed to release from mothers) was not influenced and was the same for all colors. Critical cell size for cell division in green light was shifted to a smaller size (compared with cells grown in other lights) and so was the size of released daughters. The nuclear cycle was slowed in blue and even in green light, contrary to cells grown in red and white light. At the beginning of the cell cycle, one-nucleus daughters possess approximately 10 nucleoids; during the cell cycle their number doubled in all variants before the division of nuclei. Both events were delayed in cultures grown more slowly most markedly in green light. Smaller daughters in the green variant possessed a lower number of nucleoids. Motile cells released in continuous green or blue lights but not in red one were rarely observed. PMID:17007440

  5. Boosting TAG Accumulation with Improved Biodiesel Production from Novel Oleaginous Microalgae Scenedesmus sp. IITRIND2 Utilizing Waste Sugarcane Bagasse Aqueous Extract (SBAE).

    PubMed

    Arora, Neha; Patel, Alok; Pruthi, Parul A; Pruthi, Vikas

    2016-09-01

    This investigation utilized sugarcane bagasse aqueous extract (SBAE), a nontoxic, cost-effective medium to boost triacylglycerol (TAG) accumulation in novel fresh water microalgal isolate Scenedesmus sp. IITRIND2. Maximum lipid productivity of 112 ± 5.2 mg/L/day was recorded in microalgae grown in SBAE compared to modified BBM (26 ± 3 %). Carotenoid to chlorophyll ratio was 12.5 ± 2 % higher than in photoautotrophic control, indicating an increase in photosystem II activity, thereby increasing growth rate. Fatty acid methyl ester (FAME) profile revealed presence of C14:0 (2.29 %), C16:0 (15.99 %), C16:2 (4.05 %), C18:0 (3.41 %), C18:1 (41.55 %), C18:2 (12.41), and C20:0 (1.21 %) as the major fatty acids. Cetane number (64.03), cold filter plugging property (-1.05 °C), and oxidative stability (12.03 h) indicated quality biodiesel abiding by ASTM D6751 and EN 14214 fuel standards. Results consolidate the candidature of novel freshwater microalgal isolate Scenedesmus sp. IITRIND2 cultivated in SBAE, aqueous extract made from copious, agricultural waste sugarcane bagasse to increase the lipid productivity, and could further be utilized for cost-effective biodiesel production. PMID:27093970

  6. 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

  7. Bio-oil production and removal of organic load by microalga Scenedesmus sp. using culture medium contaminated with different sugars, cheese whey and whey permeate.

    PubMed

    Borges, Wesley da Silva; Araújo, Breno Severiano Alves; Moura, Lucas Gomes; Coutinho Filho, Ubirajara; de Resende, Miriam Maria; Cardoso, Vicelma Luiz

    2016-05-15

    The objective of this study was to evaluate the bio-oil production and the organic load removal using the microalga Scenedesmus sp. The cultivation was carried out in reactors with a total volume of 3 L and 0.7 vvm aeration, with illumination in photoperiods of 12 h light/12 h dark for 12 days. The following sugar concentrations were tested: 2.5, 5.0 and 10 g/L of glucose, lactose, fructose and galactose with 10% inoculum volume. After experiments were performed with cheese whey in natura and cheese whey permeate with different lactose concentrations (1.5, 2.5, 3.5 and 5.0 g/L). In these experiments the inoculum concentrations were 10, 15, 20 and 30% (v/v). The results showed that this microalga was effective for the production of lipids when it was cultivated in medium with cheese whey in natura with 2.5 g/L of lactose and 20% inoculum (v/v). Using cheese whey in natura at the concentration of 3.5 g/L of lactose and 30% (v/v) of inoculum obtained 77.9% of TOC removal and 38.447 mg of TOC removed/mg oil produced. It was also observed that when there is increased production of bio-oil, there is less removal of organic matter. The addition of glucose, fructose or galactose in the medium did not enhance the production of bio-oil by Scenedesmus sp. when compared to lactose, but increased the organic matter removal. PMID:26948140

  8. A new lipid-rich microalga Scenedesmus sp. strain R-16 isolated using Nile red staining: effects of carbon and nitrogen sources and initial pH on the biomass and lipid production

    PubMed Central

    2013-01-01

    Background Biodiesel production from oleaginous microalgae shows great potential as a promising alternative to conventional fossil fuels. Currently, most research focus on algal biomass production with autotrophic cultivation, but this cultivation strategy induces low biomass concentration and it is difficult to be used in large-scale algal biomass production. By contrast, heterotrophic algae allows higher growth rate and can accumulate higher lipid. However, the fast-growing and lipid-rich microalgae that can be cultivated in heterotrophic system for the industrial application of biodiesel production are still few. Traditional solvent extraction and gravimetric determination to detect the microalgal total lipid content is time-consuming and laborious, which has become a major limiting factor for selecting large number of algae specimens. Thus, it is critical to develop a rapid and efficient procedure for the screening of lipid-rich microalgae. Results A novel green microalga Scenedesmus sp. strain R-16 with high total lipid content was selected using the Nile red staining from eighty-eight isolates. Various carbon sources (fructose, glucose and acetate) and nitrogen sources (nitrate, urea, peptone and yeast extract) can be utilized for microalgal growth and lipid production, and the optimal carbon and nitrogen sources were glucose (10 g L-1) and nitrate (0.6 g L-1), respectively. Compared to autotrophic situation, the strain R-16 can grow well heterotrophically without light and the accumulated total lipid content and biomass reached 43.4% and 3.46 g L-1, respectively. In addition, nitrogen deficiency led to an accumulation of lipid and the total lipid content was as high as 52.6%, and it was worth noting that strain R-16 exhibited strong tolerance to high glucose (up to 100 g L-1) and a wide range of pH (4.0-11.0). Conclusions The newly developed ultrasonic-assisted Nile red method proved to be an efficient isolation procedure and was successfully used in

  9. About the interest of a zooplankton compartment in pond systems: methodology to study the growth kinetic of Daphnia pulex on Scenedesmus sp.

    PubMed

    Liady, M N D; Tangou, T T; Fiogbe, E D; Cauchie, H-M; Vasel, J-L

    2015-01-01

    A reliable characterization of cladocerans' growth kinetic on their substrates is crucial for the estimation of their biochemical conversion rate in pond models. Although many studies reported cladocerans' growth inhibitions by high chlorophyceae contents, their growth kinetics had continued to be described in many pond system models by Monod-type kinetic, which describes growth saturation by high substrate contents, but fails to explain the disappearance of cladocerans observed during chlorophyceae's bloom periods. This study aimed to develop a methodology and assess whether growth-inhibition-type models used to describe microbial growth kinetics can be applicable to cladocerans. Experiments were carried out using Daphnia pulex populations and Scenedesmus sp. First, biomass of D. pulex was measured through digital image processing (DIP) during growth experiments. Then, three candidate models (i.e., Andrews, Edward and Haldane models), along with the Monod model, were fitted to the observed data and compared. The results showed that the DIP technique provided reliable results for estimating the biomass of D. pulex. Our findings show that the candidate growth inhibition-type models satisfactorily described D. pulex's growth kinetic (86% variance accounted for). Scenesdemus sp. were not strong inhibitors of the growth of D. pulex (high inhibition constant and low half-saturation constant found). PMID:26442483

  10. Effect of Solvent System on Extractability of Lipidic Components of Scenedesmus obliquus (M2-1) and Gloeothece sp. on Antioxidant Scavenging Capacity Thereof

    PubMed Central

    Amaro, Helena M.; Fernandes, Fátima; Valentão, Patrícia; Andrade, Paula B.; Sousa-Pinto, I.; Malcata, F. Xavier; Guedes, A. Catarina

    2015-01-01

    Microalgae are well known for their biotechnological potential, namely with regard to bioactive lipidic components—especially carotenoids and polyunsaturated fatty acids (PUFA), well-known for therapeutic applications based on their antioxidant capacity. The aim of this work was to evaluate the influence of four distinct food-grade solvents upon extractability of specific lipidic components, and on the antioxidant capacity exhibited against both synthetic (2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+•)) and biological reactive species (O2•− and •NO−). A eukaryotic microalga (Scenedesmus obliquus (M2-1)) and a prokaryotic one (Gloeothece sp.) were used as case studies. Concerning total antioxidant capacity, the hexane:isopropanol (3:2) and acetone extracts of Sc. obliquus (M2-1) were the most effective against DPPH• and ABTS+•, respectively. Gloeothece sp. ethanol extracts were the most interesting scavengers of O2•−, probably due the high content of linolenic acid. On the other hand, acetone and hexane:isopropanol (3:2) extracts were the most interesting ones in •NO− assay. Acetone extract exhibited the best results for the ABTS assay, likely associated to its content of carotenoids, in both microalgae. Otherwise, ethanol stood out in PUFA extraction. Therefore, profiles of lipidic components extracted are critical for evaluating the antioxidant performance—which appears to hinge, in particular, on the balance between carotenoids and PUFAs. PMID:26492257

  11. Effect of Solvent System on Extractability of Lipidic Components of Scenedesmus obliquus (M2-1) and Gloeothece sp. on Antioxidant Scavenging Capacity Thereof.

    PubMed

    Amaro, Helena M; Fernandes, Fátima; Valentão, Patrícia; Andrade, Paula B; Sousa-Pinto, I; Malcata, F Xavier; Guedes, A Catarina

    2015-10-01

    Microalgae are well known for their biotechnological potential, namely with regard to bioactive lipidic components-especially carotenoids and polyunsaturated fatty acids (PUFA), well-known for therapeutic applications based on their antioxidant capacity. The aim of this work was to evaluate the influence of four distinct food-grade solvents upon extractability of specific lipidic components, and on the antioxidant capacity exhibited against both synthetic (2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS(+•))) and biological reactive species (O₂(•)⁻ and (•)NO⁻). A eukaryotic microalga (Scenedesmus obliquus (M2-1)) and a prokaryotic one (Gloeothece sp.) were used as case studies. Concerning total antioxidant capacity, the hexane:isopropanol (3:2) and acetone extracts of Sc. obliquus (M2-1) were the most effective against DPPH(•) and ABTS(+•), respectively. Gloeothece sp. ethanol extracts were the most interesting scavengers of O₂(•)⁻, probably due the high content of linolenic acid. On the other hand, acetone and hexane:isopropanol (3:2) extracts were the most interesting ones in (•)NO⁻ assay. Acetone extract exhibited the best results for the ABTS assay, likely associated to its content of carotenoids, in both microalgae. Otherwise, ethanol stood out in PUFA extraction. Therefore, profiles of lipidic components extracted are critical for evaluating the antioxidant performance-which appears to hinge, in particular, on the balance between carotenoids and PUFAs. PMID:26492257

  12. [The effect of phenols on the parameters of chlorophyll fluorescence and reaction of P700 in the green algae Scenedesmus quadricauda].

    PubMed

    Matorin, D N; Plekhanov, S E; Bratkovskaia, L B; Iakovleva, O V; Alekseev, A A

    2014-01-01

    The effect of phenols, present in drains of the tsellyulozo-paper industry, on photosynthesis of the microalgae Scenedesmus quadricauda has been studied. The analysis of induction curves of the slowed-down fluorescence and light curves of non-photochemical quenching of chlorophyll fluorescence of microalgae Scenedesmus quadricauda is carried out. It was observed that energization of photosynthetic membranes was inhibited at low concentration of phenol and pyrocatechin (0.1 mM). At higher concentrations phenol and pyrocatechin inhibited electron transport in FSII and increased a share of QB not restoring centers. As a result of it the rate of P700 pigment regeneration slowed down. The results obtained indicate that parameters of induction curves of the fast and slowed-down fluorescence can be used for detecting phenol and pyrocatechin in the environment at early stages of toxic effects. PMID:25715586

  13. 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

  14. 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

  15. 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

  16. 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

  17. Scenedesmus-based treatment of nitrogen and phosphorus from effluent of anaerobic digester and bio-oil production.

    PubMed

    Kim, Ga-Yeong; Yun, Yeo-Myeong; Shin, Hang-Sik; Kim, Hee-Sik; Han, Jong-In

    2015-11-01

    In this study, a microalgae-based technology was employed to treat wastewater and produce biodiesel at the same time. A local isolate Scenedesmus sp. was found to be a well suited species, particularly for an effluent from anaerobic digester (AD) containing low carbon but high nutrients (NH3-N=273mgL(-1), total P=58.75mgL(-1)). This algae-based treatment was quite effective: nutrient removal efficiencies were over 99.19% for nitrogen and 98.01% for phosphorus. Regarding the biodiesel production, FAME contents of Scenedesmus sp. were found to be relatively low (8.74% (w/w)), but overall FAME productivity was comparatively high (0.03gL(-1)d(-1)) due to its high biomass productivity (0.37gL(-1)d(-1)). FAMEs were satisfactory to the several standards for the biodiesel quality. The Scenedesmus-based technology may serve as a promising option for the treatment of nutrient-rich wastewater and especially so for the AD effluent. PMID:26247974

  18. 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

  19. 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

  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. 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.

  4. Vernalophrys algivore gen. nov., sp. nov. (Rhizaria: Cercozoa: Vampyrellida), a New Algal Predator Isolated from Outdoor Mass Culture of Scenedesmus dimorphus

    PubMed Central

    Patterson, David J.; Li, Yunguang; Hu, Zixuan; Sommerfeld, Milton; Chen, Yongsheng

    2015-01-01

    Microbial contamination is the main cause of loss of biomass yield in microalgal cultures, especially under outdoor environmental conditions. Little is known about the identities of microbial contaminants in outdoor mass algal cultures. In this study, a new genus and species of vampyrellid amoeba, Vernalophrys algivore, is described from cultures of Scenedesmus dimorphus in open raceway ponds and outdoor flat-panel photobioreactors. This vampyrellid amoeba was a significant grazer of Scenedesmus and was frequently associated with a very rapid decline in algal numbers. We report on the morphology, subcellular structure, feeding behavior, molecular phylogeny, and life cycle. The new amoeba resembles Leptophrys in the shape of trophozoites and pseudopodia and in the mechanism of feeding (mainly by engulfment). It possesses two distinctive regions in helix E10_1 (nucleotides 117 to 119, CAA) and E23_1 (nucleotides 522 and 523, AG) of the 18S rRNA gene. It did not form a monophyletic group with Leptophrys in molecular phylogenetic trees. We establish a new genus, Vernalophrys, with the type species Vernalophrys algivore. The occurrence, impact of the amoeba on mass culture of S. dimorphus, and means to reduce vampyrellid amoeba contamination in Scenedesmus cultures are addressed. The information obtained from this study will be useful for developing an early warning system and control measures for preventing or treating this contaminant in microalgal mass cultures. PMID:25819973

  5. Vernalophrys algivore gen. nov., sp. nov. (Rhizaria: Cercozoa: Vampyrellida), a New Algal Predator Isolated from Outdoor Mass Culture of Scenedesmus dimorphus.

    PubMed

    Gong, Yingchun; Patterson, David J; Li, Yunguang; Hu, Zixuan; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2015-06-15

    Microbial contamination is the main cause of loss of biomass yield in microalgal cultures, especially under outdoor environmental conditions. Little is known about the identities of microbial contaminants in outdoor mass algal cultures. In this study, a new genus and species of vampyrellid amoeba, Vernalophrys algivore, is described from cultures of Scenedesmus dimorphus in open raceway ponds and outdoor flat-panel photobioreactors. This vampyrellid amoeba was a significant grazer of Scenedesmus and was frequently associated with a very rapid decline in algal numbers. We report on the morphology, subcellular structure, feeding behavior, molecular phylogeny, and life cycle. The new amoeba resembles Leptophrys in the shape of trophozoites and pseudopodia and in the mechanism of feeding (mainly by engulfment). It possesses two distinctive regions in helix E10_1 (nucleotides 117 to 119, CAA) and E23_1 (nucleotides 522 and 523, AG) of the 18S rRNA gene. It did not form a monophyletic group with Leptophrys in molecular phylogenetic trees. We establish a new genus, Vernalophrys, with the type species Vernalophrys algivore. The occurrence, impact of the amoeba on mass culture of S. dimorphus, and means to reduce vampyrellid amoeba contamination in Scenedesmus cultures are addressed. The information obtained from this study will be useful for developing an early warning system and control measures for preventing or treating this contaminant in microalgal mass cultures. PMID:25819973

  6. 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

  7. Biodiesel production from algae oil high in free fatty acids by two-step catalytic conversion.

    PubMed

    Chen, Lin; Liu, Tianzhong; Zhang, Wei; Chen, Xiaolin; Wang, Junfeng

    2012-05-01

    The effect of storage temperature and time on lipid composition of Scenedesmus sp. was studied. When stored at 4°C or higher, the free fatty acid content in the wet biomass increased from a trace to 62.0% by day 4. Using two-step catalytic conversion, algae oil with a high free fatty acid content was converted to biodiesel by pre-esterification and transesterification. The conversion rate of triacylglycerols reached 100% under the methanol to oil molar ratio of 12:1 during catalysis with 2% potassium hydroxide at 65°C for 30 min. This process was scaled up to produce biodiesel from Scenedesmus sp. and Nannochloropsis sp. oil. The crude biodiesel was purified using bleaching earth. Except for moisture content, the biodiesel conformed to Chinese National Standards. PMID:22401712

  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. 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

  10. 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

  11. 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

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Nutritional And Taste Characteristics Of Algae

    NASA Technical Reports Server (NTRS)

    Karel, M.; Nakhost, Z.

    1992-01-01

    Report describes investigation of chemical composition of blue-green algae Synechococcus 6311, as well as preparation of protein isolate from green alga Scenedesmus obliquus and incorporation into variety of food products evaluated for taste. Part of program to investigate growth of microalgae aboard spacecraft for use as food.

  12. 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

  13. Age affects not only metabolome but also metal toxicity in Scenedesmus quadricauda cultures.

    PubMed

    Kováčik, Jozef; Klejdus, Bořivoj; Babula, Petr; Hedbavny, Josef

    2016-04-01

    Responses of Scenedesmus quadricauda grown in vitro and differing in age (old culture-13 months, young culture-1 month) to short-term cadmium (Cd) or nickel (Ni) excess (24h) were compared. Higher age of the culture led to lower amount of chlorophylls, ascorbic acid and glutathione but higher signal of ROS. Surprisingly, sucrose was detected using DART-Orbitrap MS in both old and young culture and subsequent quantification confirmed its higher amount (ca. 3-times) in the old culture. Cd affected viability and ROS amount more negatively than Ni that could arise from excessive Cd uptake which was also higher in all treatments than in respective Ni counterparts. Surprisingly, nitric oxide was not extensively different in response to age or metals. Strong induction of phytochelatin 2 is certainly Cd-specific response while Ni also elevated ascorbate content. Krebs cycle acids were more accumulated in the young culture but they were rather elevated in the old culture (citric acid under Ni excess). We conclude that organic solid 'Milieu Bristol' medium we tested is suitable for long-term storage of unicellular green algae (also successfully tested for Coccomyxa sp. and Parachlorella sp.) and the impact of age on metal uptake may be useful for bioremediation purposes. PMID:26687303

  14. 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

  15. 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

  16. 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

  17. 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

  18. Grazer-induced morphological defense in Scenedesmus obliquus is affected by competition against Microcystis aeruginosa

    PubMed Central

    Zhu, Xuexia; Wang, Jun; Lu, Yichun; Chen, Qinwen; Yang, Zhou

    2015-01-01

    The green alga Scenedesmus is known for its phenotypic plasticity in response to grazing risk. However, the benefits of colony formation induced by infochemicals from zooplankton should come with costs. That is, a tradeoff in benefit-to-cost ratios is likely under complex environmental conditions. In this study, we hypothesized that the coexistence of Scenedesmus and its competitors decreases the formation of anti-grazer colonies in Scenedesmus. Results demonstrated that the presence of a competitor Microcystis aeruginosa inhibited inducible defensive colony formation of Scenedesmus obliquus, and the established defensive colonies negatively affected the competitive ability of S. obliquus. The proportion of induced defensive colonies in cultures was dependent on the relative abundance of competitors. Under low competition intensity, large amount of eight-celled colonies were formed but at the cost of decreased competitive inhibition on M. aeruginosa. By contrast, defensive colony formation of S. obliquus slacked in the presence of high competition intensity to maintain a high displacement rate (competitive ability). In conclusion, S. obliquus exhibited different responses to potential grazing pressure under different intensities of competition, i.e., Scenedesmus morphological response to grazing infochemicals was affected by competition against Microcystis. PMID:26224387

  19. Cadmium induced potassium efflux from Scenedesmus quadricauda

    SciTech Connect

    Reddy, G.N.; Prasad, M.N.V.

    1992-10-01

    Plants, algae and bacteria respond to heavy metal toxicity by inducing different enzymes, ion influx/efflux for ionic balance and synthesize small peptides such as poly({gamma}-glutamyl cysteinyl) glycines called phytochelatins (PCs) mainly consisting of glutamate, cysteine and glycine. These peptides bind metal ions and reduce toxicity. The uptake of metal ions comprises two phases. The first phase consists of a quick and nonspecific binding of the cations to negatively-charged membrane components located at the cell surface. The second phase consists of energy-dependent intracellular uptake of the metal ions. During uptake of Co{sup 2+} by yeast cells, an electroneutral 2:1 exchange with K{sup +} was found. Cd{sup 2+} uptake by yeast also caused loss of cell K{sup +}, however, there was no electroneutral exchange of K{sup +}. The molar ratio of K{sup +} released and Cd{sup 2+} accumulated by yeast in the initial stage of incubation is 22 and seems to be independent of the Cd concentration. Disruption of the cell membrane of part of the cells, according to an all-or-none process, by Cd{sup 2+} may explain the disproportional loss of cell K{sup +} during Cd{sup 2+} uptake. This paper examines the exchange of K{sup +} with Cd{sup 2+} uptake in Scenedesmus quadricauda, and whether it follows an electroneutral 2:1 exchange or an all-or-none process. 11 refs., 2 figs.

  20. 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...

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  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. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. Identification and characterization of a freshwater microalga Scenedesmus SDEC-8 for nutrient removal and biodiesel production.

    PubMed

    Song, Mingming; Pei, Haiyan; Hu, Wenrong; Zhang, Shuo; Ma, Guixia; Han, Lin; Ji, Yan

    2014-06-01

    The selection of the right strains is of fundamental important to the success of the algae-based oil industry. From the six newly isolated microalgae strains tested for growth, fatty acid methyl ester (FAME) profiles and biodiesel properties, Scenedesmus SDEC-8, with favorable C16:0 fatty acids (73.43%), showed the best combined results. Then, morphological and molecular identification were examined. From the three wastewaters samples, Scenedesmus SDEC-8 showed good ability to yield oil and remove nutrients, which were comparable with other reports. In b artificial wastewater (TN 40 mg L(-1), TP 8 mg L(-1)), Scenedesmus SDEC-8 achieved the highest value of lipid productivity (53.84 mg L(-1) d(-1)), MUFA content (35.35%) and total FAME content (59.57±0.02 mg g(-1) DW), besides higher removal efficiencies of TN (99.18%) and TP (98.86%) helped effluent directly discharge and smaller dilution factor of N, P (3.3 and 9) which was good for lessening water utilization. PMID:24747391

  18. 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

  19. Cultivation of Scenedesmus obliquus in liquid hydrolysate from flash hydrolysis for nutrient recycling.

    PubMed

    Barbera, Elena; Sforza, Eleonora; Kumar, Sandeep; Morosinotto, Tomas; Bertucco, Alberto

    2016-05-01

    The production of biofuels from microalgae is associated with high demands of nutrients (nitrogen and phosphorus) required for growth. Recycling nutrients from the residual biomass is essential to obtain a sustainable production. In this work, the aqueous phase obtained from flash hydrolysis of Scenedesmus sp. was used as cultivation medium for a microalga of the same genus, to assess the feasibility of this technique for nutrient recycling purposes. Batch and continuous cultivations were carried out, to determine growth performances in this substrate compared to standard media, and verify if a stable biomass production could be obtained. In continuous experiments, the effect of hydrolysate inlet concentration and of residence time were assessed to optimize nutrient supply in relation to productivity. Results obtained show that nutrient recycling is feasible by treating biomass with flash hydrolysis, and Scenedesmus is capable of recycling large amounts of recovered nutrients. PMID:26868157

  20. Influence of barley straw (Hordeum vulgare L.) extract on phytoplankton dominated by Scenedesmus species in laboratory conditions: the importance of the extraction duration.

    PubMed

    Pęczuła, Wojciech

    2013-04-01

    The response of a natural phytoplankton assemblage dominated by algae of the genus Scenedesmus to the addition of barley straw extract was studied in a laboratory experiment. The aim of the study was to compare the inhibiting effect of water extracts obtained by soaking the straw for 1, 2 and 3 months. We analysed the response of four species, Scenedesmus subspicatus, Scenedesmus ecornis, Scenedesmus quadricauda and Scenedesmus acuminatus, during 14 days of their exposure to different types of barley straw extract. S. subspicatus and S. ecornis responded with decreasing numbers only to the addition of the 3-month solution (ANOVA; F = 290.1, p <0.001; and F = 11.8, p <0.01, respectively); the two other species were inhibited by all types of extracts. The results indicate the need for more research on the importance of extraction duration to the inhibitory abilities of barley straw which can be applied in the management of water quality in water bodies. PMID:23482372

  1. 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

  2. Morpho-physiological effects of ibuprofen on Scenedesmus rubescens.

    PubMed

    Moro, Isabella; Matozzo, Valerio; Piovan, Anna; Moschin, Emanuela; Vecchia, Francesca Dalla

    2014-09-01

    The pollution of aquatic bodies by drugs is an emerging environmental problem, because of their extensive use in animal and human context. Ibuprofen, 2-[4-(2-methylpropyl)phenyl]propanoic acid, is the non-steroidal anti-inflammatory drug mainly present both in wastewater and in rivers and lakes in Europe. Since in literature there is little information about the effects of ibuprofen on microalgae, in this paper we presented the results on the effects of this molecule at different concentrations (62.5μgL(-1), 250μgL(-1) and 1000μgL(-1)) on cultures of the freshwater microalga Scenedesmus rubescens (P.J.L. Dangeard) E. Kesslet et al. Ibuprofen effects on the alga were assayed at first through analyses of the growth curve. Moreover, analyses of cell morphology, ultrastructure, and photosynthetic pigments were additionally performed. The first negative effect of the drug was on the microalga growth, suggesting a drug action dose-dependent mechanism type, more evident at the concentration of 1000μgL(-1) ibuprofen and in the last phase of the growth curve. In support of this, following ibuprofen exposure, the cells exhibited morphological and ultrastructural alterations, mainly consisting in large cytoplasmic inclusions, probably of lipids and/or carotenoids. The decrease of chlorophyll amounts and, on the contrary, the increase of carotenoids were correlated with a stressful condition induced by drug. PMID:25128768

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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.)...

  8. 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

  9. Nitrogen recycling from fuel-extracted algal biomass: residuals as the sole nitrogen source for culturing Scenedesmus acutus.

    PubMed

    Gu, Huiya; Nagle, Nick; Pienkos, Philip T; Posewitz, Matthew C

    2015-05-01

    In this study, the reuse of nitrogen from fuel-extracted algal residues was investigated. The alga Scenedesmus acutus was found to be able to assimilate nitrogen contained in amino acids, yeast extracts, and proteinaceous alga residuals. Moreover, these alternative nitrogen resources could replace nitrate in culturing media. The ability of S. acutus to utilize the nitrogen remaining in processed algal biomass was unique among the promising biofuel strains tested. This alga was leveraged in a recycling approach where nitrogen is recovered from algal biomass residuals that remain after lipids are extracted and carbohydrates are fermented to ethanol. The protein-rich residuals not only provided an effective nitrogen resource, but also contributed to a carbon "heterotrophic boost" in subsequent culturing, improving overall biomass and lipid yields relative to the control medium with only nitrate. Prior treatment of the algal residues with Diaion HP20 resin was required to remove compounds inhibitory to algal growth. PMID:25539998

  10. 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

  11. 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

  12. Effects of imidazolium chloride ionic liquids and their toxicity to Scenedesmus obliquus.

    PubMed

    Liu, Huijun; Zhang, Xiaoqiang; Chen, Caidong; Du, Shaoting; Dong, Ying

    2015-12-01

    The low volatility of ionic liquids effectively eliminates a major pathway for environmental release and contamination; however, the good solubility, low degree of environmental degradation and biodegradation of ILs may pose a potential threat to the aquatic environment. The growth inhibition of the green alga Scenedesmus obliquus by five 1-alkyl-3-methylimidazolium chloride ionic liquids (ILs) ([Cnmim]Cl, n=6, 8, 10, 12, 16) was investigated, and the effect on cellular membrane permeability and the ultrastructural morphology by ILs ([Cnmim]Cl, n=8, 12, 16) were studied. The results showed that the growth inhibition rate increased with increasing IL concentration and increasing alkyl chain lengths. The relative toxicity was determined to be [C6mim]Cl<[C8mim]Cl<[C10mim]Cl<[C12mim]Cl<[C16mim]Cl. The algae were most sensitive to imidazolium chloride ILs at 48 h according to the results from the growth inhibition rate and cellular membrane permeability tests. The ultrastructural morphology showed that the ILs had negative effects on the cellular morphology and structure of the algae. The cell wall of treated algae became wavy and separated from the cell membrane. Chloroplast grana lamellae became obscure and loose, osmiophilic material was deposited in the chloroplast, and mitochondria and their cristae swelled. Additionally, electron-dense deposits were observed in the vacuoles. PMID:26218552

  13. [Individual and joint stress of lead and mercury on growth, glutathione and glutathione-related enzymes of Scenedesmus quadricauda].

    PubMed

    Li, Yan; Zhu, Lin; Liu, Shuo

    2009-01-01

    To understand the toxicity mechanisms of mixed heavy metals on aquatic plant, indicators of algea growth rate,content of reduced glutathione (GSH), activities of glutathione S-transferase (GST) and glutathione peroxidase (GPx) of green algae, Scenedesmus quadricauda were measured to analyze the individual and joint toxic effects of lead and mercury. The results show that the 96h EC50 of algae growth inhibition by lead [Pb(NO3)2] and mercury (HgCl2) are 0.6789 mg/L and 0.1401 mg/L respectively. After 12 h individual and joint lead and mercury exposure, the content of GSH in alga cells is decreased to about 70% of the level of the control, and keeps a steady level with the increase of the exposure concentration. The GST activities are increased to a peak in lower concentration groups and then decrease with the increase of the exposure concentration. Indeed,the higher concentration of lead and mercury combined-poisoning can inhibit the activities of GST significantly, with 13.04% inhibitory rate. The activity of GPx is almost suppressed continuously with the increase of the exposure concentration, and the lowest activity is only 38.77% of the control. The toxic action of the mixture of Pb and Hg on growth inhibition,GSH content,activities of GST and activities of GPx for Scenedesmus quadricauda are addition. PMID:19353889

  14. 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

  15. 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

  16. Herbicides interfere with antigrazer defenses in Scenedesmus obliquus.

    PubMed

    Zhu, Xuexia; Sun, Yunfei; Zhang, Xingxing; Heng, Hailu; Nan, Haihong; Zhang, Lu; Huang, Yuan; Yang, Zhou

    2016-11-01

    The extensive application of herbicides has led to a serious threat of herbicide contamination to aquatic ecosystem. Herbicide exposure affects aquatic communities not only by exerting toxicity on single species but also by changing interspecific interactions. This study investigated the antigrazer defenses of the common green alga Scenedesmus obliquus against different herbicides [glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), and atrazine] at various concentrations (0-2.0 mg L(-1)). In the presence of grazer (Daphnia)-derived cues, S. obliquus populations without herbicides formed high proportions of multicelled (e.g., four- and eight-celled) colonies. This result confirms that S. obliquus exhibits a morphological defense against grazing risk. At the low concentration range of 0.002-0.02 mg L(-1), the three herbicides exerted no influence on the growth and photosynthetic efficiency of S. obliquus, and multicelled colonies showed constant proportions. At the high concentration range of 0.20-2.0 mg L(-1), atrazine significantly inhibited the algal growth and photosynthesis whereas glyphosate or 2,4-D did not. Nonetheless, these levels of glyphosate or 2,4-D remarkably decreased the proportion of multicelled colonies, with reduced numbers of cells per particle in Daphnia filtrate-treated population. No eight-celled colony was formed after treatment with atrazine at 0.20-2.0 mg L(-1) despite the addition of Daphnia filtrate. These results suggest that herbicide exposure impairs antigrazer colonial morphs in phytoplankton although it is not sufficient to hamper algal growth. This phenomenon can increase the risk of predation by herbivores, thereby disrupting the inducible phytoplankton community. Furthermore, the predator-prey interactions between herbivores and phytoplankton can be potentially changed more seriously than previously considered. PMID:27501311

  17. 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.

  18. 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

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

    PubMed

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

    2014-12-01

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

  4. 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

  5. Host cell pigmentation in Scenedesmus dimorphus as a beacon for nascent parasite infection.

    PubMed

    Collins, Aaron M; Jones, Howland D T; McBride, Robert C; Behnke, Craig; Timlin, Jerilyn A

    2014-09-01

    Biofuels derived from the mass cultivation of algae represent an emerging industry that aims to partially displace petroleum based fuels. Outdoor, open-pond, and raceway production facilities are attractive options for the mass culture of algae however, this mode of cultivation leaves the algae susceptible to epidemics from a variety of environmental challenges. Infestations can result in complete collapse of the algal populations and destruction of their valuable products making it paramount to understand the host-pathogen relationships of known algal pests in order to develop mitigation strategies. In the present work, we characterize the spatial-temporal response of photosynthetic pigments in Scenedesmus dimorphus to infection from Amoeboaphelidium protococcarum, a destructive endoparasite, with the goal of understanding the potential for early detection of infection via host pigment changes. We employed a hyperspectral confocal fluorescence microscope to quantify these changes in pigmentation with high spatial and spectral resolution during early parasite infection. Carotenoid abundance and autofluorescence increased within the first 24 h of infection while chlorophyll emission remained constant. Changes in host cell photosynthesis and bulk chlorophyll content were found to lag behind parasite replication. The results herein raise the possibility of using host-cell pigment changes as indicators of nascent parasite infection. PMID:24931928

  6. 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

  7. Construction and application of the Synechocystis sp. PCC6803-ftnA in microbial contamination control in a coupled cultivation and wastewater treatment.

    PubMed

    Zhang, Yalei; Zhang, Chunmin; Zhou, Xuefei; Shen, Zheng; Zhao, Fangchao; Zhao, Jianfu

    2016-08-01

    Inspired by iron fertilization experiments in HNLC (high-nitrate, low-chlorophyll) sea areas, we proposed the use of iron-rich engineered microalgae for microbial contaminant control in iron-free culture media. Based on the genome sequence and natural transformation system of Synechocystis sp. PCC6803, ftnA (encoding ferritin) was selected as our target gene and was cloned into wild-type Synechocystis sp. PCC6803. Tests at the molecular level confirmed the successful construction of the engineered Synechocystis sp. PCC6803-ftnA. After Fe(3+)-EDTA pulsing, the intracellular iron content of Synechocystis sp. PCC6803-ftnA was significantly enhanced, and the algae was used in the microbial contamination control system. In the coupled Synechocystis sp. PCC6803-ftnA production and municipal wastewater (MW, including Scenedesmus obliquus and Bacillus) treatment, Synechocystis sp. PCC6803-ftnA accounted for all of the microbial activity and significantly increased from 70% of the microbial community to 95%. These results revealed that while the stored iron in the Synechocystis sp. PCC6803-ftnA cells was used for growth and reproduction of this microalga in the MW, the growth of other microbes was inhibited because of the iron limitation, and these results provide a new method for microbial contamination control during a coupling process. PMID:27521949

  8. Prevent the degradation of algicidal ability in Scenedesmus-lysing bacteria using optimized cryopreservation.

    PubMed

    Liao, Chunli; Liu, Xiaobo

    2016-03-01

    With the anthropogenic nutrient loading increasing, the frequency and impacts of harmful algal blooms (HABs) have intensified in recent years. To biocontrol HABs, many corresponding algal-lysing bacteria have been exploited successively. However, there are few studies on an effective algal-lysing culture collection to prevent cells from death and particularly the degradation of algicidal ability to their hosts. An optimized cryopreservation was developed and experiments on the validation of this method on preventing algicidal degradation and effects of this optimized cryopreservation on the survival rate of Scenedesmus-lysing bacterium, Enterobacter NP23, isolated from Scenedesmus sp. community, China, on the algicidal dynamic of Scenedesmus wuhanensis was investigated. The optimized cryoprotectant composition consists of 30.0 g/L gelatin, 48.5 g/L sucrose, and 28.4 g/L glycerol, respectively. Using this approach, the survival rate of NP23 cells can still maintain above 90 % and the algal-lysing rate only decline 4 % after the 18-month cryoprotection. Moreover, the 16 generations' passage experiment showed a significant (p < 0.05) genetic stability of algicidal capacity after 18 months. The growth dynamic of S. wuhanensis was investigated in a 5-L bioreactor during 132 h in the absence or presence of NP23. As a result, NP23 has a significant (p < 0.05) inhibition to S. wuhanensis growth when injected into algal culture in the exponential phase at 60th hour. In addition, S. wuhanensis culture initially with NP23 exhibited a slow growth, performing a prolonged lag phase without a clear stationary phase and then rapidly decreased. Our findings, combined with the capacity of preventing the degradation of algicidal ability collectively suggest that the use of this opitimized cryopreservation may be a promising strategy for maintaining algicidal cells. PMID:26593730

  9. 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

  10. Uptake and effect of highly fluorescent silver nanoclusters on Scenedesmus obliquus.

    PubMed

    Zhang, Li; He, Yiliang; Goswami, Nirmal; Xie, Jianping; Zhang, Bo; Tao, Xianji

    2016-06-01

    The release of silver nanoparticles (Ag NPs) in aquatic environment has caused wide public concern about their effects on living organisms (e.g., algae). However, how these small NPs exert cytotoxicity in the living organisms has always been under heated debate. In this study, the uptake and toxicity effects of strongly red-emitting fluorescent silver nanoclusters (r-Ag NCs) exposed to the green algae Scenedesmus obliquus was investigated. Upon exposure to pure r-Ag NCs and r-Ag NCs containing l-cysteine, the algae growth inhibition test showed that Ag(+) ions released from r-Ag NCs played an important role in the toxicity of r-Ag NCs along with the toxicity of intact r-Ag NCs. Furthermore, no signals of intracellular reactive oxygen species (ROS) were observed indicating that r-Ag NCs or released Ag(+) ions - mediated growth inhibition of algae cells was independent of ROS production. Transmission electron microscopy (TEM) and laser scanning confocal microscopy (LSCM) were employed to study cellular uptake and cytotoxicity. Furthermore, analysis of differential expressed gene demonstrated that r-Ag NCs as well as the released Ag(+) ions can simultaneously exist inside the algae cells, and inhibit the transcriptomic process of genes by their "joint-toxicity" mechanism. Taken together, our study provides a new insight into the molecular mechanisms of r-Ag NCs and Ag(+) ions exposure to the aquatic organism and can be applied to early diagnosis of ecologic risk mediated by others metal-based NPs. PMID:27023120

  11. Biomass production and fatty acid profile of a Scenedesmus rubescens-like microalga.

    PubMed

    Tan, Yixin; Lin, Junda

    2011-11-01

    This investigation examined the effects of nitrogen-phosphate combined deficiency on the biomass yield, fatty acid methyl esters (FAME) production and composition from Scenedesmus rubescens-like microalga. A 15-day indoor culture was performed as a 3 × 3 factorial design (NaNO(3) levels: 3, 10 and 20mM; KH(2)PO(4) levels: 20, 50 and 150 μM). The algae grown under medium nitrogen concentration (10mM) and high phosphate concentration (150 μM) reached the highest biomass (1223.5 ± 152.5mg/L). Both nitrogen and phosphate had a significant influence on the FAME yield (P<0.05 and P<0.0001, respectively). The FAME yield from algae grown under low nitrogen (3mM) and phosphate concentration (20 μM) increased throughout the experiment and the highest FAME yield (42.2 ± 2.5% of AFDW) as well as C16 and C18 content (95.8 ± 1.6% of AFDW) was achieved under these conditions. Algae grown under medium nitrogen concentration (10mM) and low phosphate concentration (20 μM) had the highest FAME productivity (426.0mg/L ± 135.0mg/L). Thus, the lower nitrogen concentration (3mM-10mM) and low phosphate concentration (20 μM) would be an optimal combination tested to produce the most FAME from S. rubescens-like algae. PMID:21903386

  12. Phosphorus-limited growth of a green alga and a blue-green alga

    SciTech Connect

    Lang, D.S.; Brown, E.J.

    1981-12-01

    The phosphorus-limited growth kinetics of the chlorophyte Scenedesmus quadricauda and the cyanophyte Synechococcus Nageli were studied by using batch and continuous culturing techniques. The steady-state phosphate transport capability and the phosphorus storage capacity is higher in S. Nageli than in S. quadricauda. Synechococcus Nageli can also deplete phosphate to much lower levels than can S. quadricauda. These results, along with their morphological characteristics, were used to construct partial physiological profiles for each organism. The profiles indicate that this unicellular cyanophyte (cyanobacterium) is better suited for growth in phosphorus-limited oligotrophic niches than is this chlorophyte (green alga). (Refs. 44).

  13. 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

  14. Costs and trade-offs of grazer-induced defenses in Scenedesmus under deficient resource

    PubMed Central

    Zhu, Xuexia; Wang, Jun; Chen, Qinwen; Chen, Ge; Huang, Yuan; Yang, Zhou

    2016-01-01

    The green alga Scenedesmus obliquus can form inducible defensive morphs under grazing threat. Costs and trade-offs of inducible defense are expected to accompany the benefits of defensive morphs, but are hard to detect under nutrient-sufficient experimental conditions. To test the existence of costs associated with inducible defense, we cultured S. obliquus along resource availability gradients in the presence or absence of infochemical cues from Daphnia, and measured the strength of defensive colony formation and fitness characters. Under the lowest phosphorous concentration, the expression of inducible defensive colony resulted in decreased growth rate, which provides direct evidence for physiological costs. Along the gradient reduction of phosphorous concentration or light intensity, inducible defense in S. obliquus showed a decreasing trend. However, the photosynthetic efficiency of S. obliquus was barely affected by its defense responses, suggesting that the negative correlations between resource availability and colony formation of this alga may be due to resource-based trade-offs in the allocation of limited resources. Thus, our results indicated that expression of inducible defense of S. obliquus was impaired under insufficient phosphorus or light. Furthermore, under severe phosphate deficiency, obvious physiological costs of inducible defense could be detected even though defensive colony formation also decreased significantly. PMID:26932369

  15. Anaerobic Digestion of Algae Biomass to Produce Energy during Wastewater Treatment.

    PubMed

    Peng, Shanshan; Colosi, Lisa M

    2016-01-01

    Water resource recovery facilities (WRRFs) are asked to improve both energy efficiency and nutrient removal efficacy. Integration of algaculture offers several potential synergies that could address these goals, including an opportunity to leverage anaerobic digestion at WRRFs. In this study, bench-scale experiments are used to measure methane yield during co-digestion of Scenedesmus dimorphus or mixed WRRF-grown algae with WRRF biosolids. The results indicate that normalized methane yield decreases with increasing algae content in a manner than can be reasonably well fit using linear regression (R(2) = 67%). It is thus possible to predict methane yield for any mixture of algae and biosolids based on the methane yield of the biosolids alone. Using revised methane yields, the energy return on investment of a typical WRRF increases from 0.53 (without algae) to 0.66 (with algae). Thus, algae-based wastewater treatment may hold promise for improving WRRF energy efficiency without compromising effluent quality. PMID:26803024

  16. Conversion of biogas to bioproducts by algae and methane oxidizing bacteria.

    PubMed

    van der Ha, David; Nachtergaele, Leen; Kerckhof, Frederiek-Maarten; Rameiyanti, Devi; Bossier, Peter; Verstraete, Willy; Boon, Nico

    2012-12-18

    Biogas produced by anaerobic digestion is typically converted into electricity and low value heat. In this study, biogas is microbially transformed into valuable bioproducts. As proof of principle, the production of feed additives, i.e. lipids and polyhydroxybutyrate, out of biogas was evaluated. In a first stage, the CO₂ in a synthetic biogas was photosynthetically fixed by an algae Scenedesmus sp. culture at an average rate of 192 ± 9 mg CO₂ L⁻¹ liquid d⁻¹, resulting in concomitant O₂ production. After N-depletion, more than 30% of the 220 ± 7 mg lipids g⁻¹ total organic carbon were unsaturated. In a second stage, the theoretical resulting gas mixture of 60% CH₄ and 40% O₂ was treated by a methane oxidizing Methylocystis parvus culture, with oxidation rates up to 452 ± 7 mg⁻¹ CH₄-C L⁻¹ liquid d⁻¹. By repeated N-limitation, concentrations of 295 ± 50 mg intracellular polyhydroxybutyrate g⁻¹ cell dry weight were achieved. Finally, a one-stage approach with controlled coculturing of both microbial groups resulted in harvestable bioflocs. This is the first time that a total microbial conversion of both greenhouse gases into biomass was achieved without external O₂ provision. Based on these results, a biotechnological approach is discussed whereby all kinds of biogas can be transformed into valuable bioproducts. PMID:23186036

  17. 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

  18. 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)

  19. Cadmium tolerance, cysteine and thiol peptide levels in wild type and chromium-tolerant strains of Scenedesmus acutus (Chlorophyceae).

    PubMed

    Torricelli, Elena; Gorbi, Gessica; Pawlik-Skowronska, Barbara; Di Toppi, Luigi Sanità; Corradi, Maria Grazia

    2004-07-14

    Two strains of the unicellular green alga Scenedesmus acutus with different sensitivity to hexavalent chromium were compared for their tolerance of cadmium, by means of growth and recovery tests, and determination of cysteine, reduced glutathione and phytochelatin content, after short-term exposure to various cadmium concentrations (from 1.125 to 27 microM). Growth experiments showed that, after 7-day treatments with cadmium, the chromium-tolerant strain reached a significantly higher cell density and, after 24-h exposure to Cd, was able to resume growth significantly better than the wild type. Constitutive level of cysteine was higher in the chromium-tolerant strain, while glutathione levels were similar in the two strains. The higher content of cysteine and the maintenance of both reduced glutathione and phytochelatin high levels in the presence of cadmium, support the higher cadmium co-tolerance of the chromium-tolerant strain in comparison with the wild type one. PMID:15177949

  20. 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

  1. Toxic responses and antioxidative enzymes activity of Scenedesmus obliquus exposed to fenhexamid and atrazine, alone and in mixture.

    PubMed

    Mofeed, Jelan; Mosleh, Yahia Y

    2013-09-01

    Laboratory studies were conducted to determine the effects of different concentrations of fenhexamid and atrazine (25, 50 and 100 µg L(-1)) on growth and oxidative stress on Scenedesmus obliquus (microalgae) after exposure for 24, 48, and 96 h. In addition, residues of fenhexamid and atrazine were determined in the culture medium after 96 h; 52%, 44% and 43% of fenhexamid remained in the medium for the lowest, middle and highest concentrations, respectively. Atrazine concentration decreased significantly in the medium with time. The reduction was faster with the lowest concentration (-53%), than in the highest concentration (-46%), while it was intermediate with 50 µg L(-1) (-47%). The antioxidative enzyme activities were used as biomarkers to evaluate the toxic effects of fenhexamid and atrazine on the microalgae. Enzymatic activities were measured in the presence of each compound alone after 24, 48 and 96 h and also in mixture after 24h exposure. The results showed that fenhexamid and atrazine induced antioxidative enzyme activities (GST, CAT and GR) at different concentrations. Catalase activities (CAT) in both pesticides treated-algae were significantly increased. Additionally, an increase in gulathione-S-transferase (GST) was observed in algae after 24, 48 and 96 h of exposure to both fenhexamid and atrazine. Antioxidative enzymes in fenhexamid and atrazine mixture treatment showed an antagonistic interaction after 24h of exposure in algae. PMID:23796667

  2. Utilization of non-conventional systems for conversion of biomass to food components: Potential for utilization of algae in engineered foods

    NASA Technical Reports Server (NTRS)

    Karel, M.; Kamarei, A. R.; Nakhost, Z.

    1985-01-01

    The major nutritional components of the green algae (Scenedesmus obliquus) grown in a Constant Cell density Apparatus were determined. Suitable methodology to prepare proteins from which three major undesirable components of these cells (i.e., cell walls, nucleic acids, and pigments) were either removed or substantially reduced was developed. Results showed that processing of green algae to protein isolate enhances its potential nutritional and organoleptic acceptability as a diet component in a Controlled Ecological Life Support System.

  3. 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

  4. 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

  5. Effect of static magnetic field on the oxygen production of Scenedesmus obliquus cultivated in municipal wastewater.

    PubMed

    Tu, Renjie; Jin, Wenbiao; Xi, Tingting; Yang, Qian; Han, Song-Fang; Abomohra, Abd El-Fatah

    2015-12-01

    Algal-bacterial symbiotic system, with biological synergism of physiological functions of both algae and bacteria, has been proposed for cultivation of microalgae in municipal wastewater for biomass production and wastewater treatment. The algal-bacterial symbiotic system can enhance dissolved oxygen production which enhances bacterial growth and catabolism of pollutants in wastewater. Therefore, the oxygen production efficiency of microalgae in algal-bacterial systems is considered as the key factor influencing the wastewater treatment efficiency. In the present study, we have proposed a novel approach which uses static magnetic field to enhance algal growth and oxygen production rate with low operational cost and non-toxic secondary pollution. The performance of oxygen production with the magnetic field was evaluated using Scenedesmus obliquus grown in municipal wastewater and was calculated based on the change in dissolved oxygen concentration. Results indicated that magnetic treatment stimulates both algal growth and oxygen production. Application of 1000 GS of magnetic field once at logarithmic growth phase for 0.5 h increased the chlorophyll-a content by 11.5% over the control after 6 days of growth. In addition, magnetization enhanced the oxygen production rate by 24.6% over the control. Results of the study confirmed that application of a proper magnetic field could reduce the energy consumption required for aeration during the degradation of organic matter in municipal wastewater in algal-bacterial symbiotic systems. PMID:26253865

  6. Modelling the effect of fluctuating herbicide concentrations on algae growth.

    PubMed

    Copin, Pierre-Jean; Coutu, Sylvain; Chèvre, Nathalie

    2015-03-01

    Herbicide concentrations fluctuate widely in watercourses after crop applications and rain events. The level of concentrations in pulses can exceed the water chronic quality criteria. In the present study, we proposed modelling the effects of successive pulse exposure on algae. The deterministic model proposed is based on two parameters: (i) the typical growth rate of the algae, obtained by monitoring growth rates of several successive batch cultures in growth media, characterizing both the growth of the control and during the recovery periods; (ii) the growth rate of the algae exposed to pulses, determined from a dose-response curve obtained with a standard toxicity test. We focused on the herbicide isoproturon and on the freshwater alga Scenedesmus vacuolatus, and we validated the model prediction based on effect measured during five sequential pulse exposures in laboratory. The comparison between the laboratory and the modelled effects illustrated that the results yielded were consistent, making the model suitable for effect prediction of the herbicide photosystem II inhibitor isoproturon on the alga S. vacuolatus. More generally, modelling showed that both pulse duration and level of concentration play a crucial role. The application of the model to a real case demonstrated that both the highest peaks and the low peaks with a long duration affect principally the cell density inhibition of the alga S. vacuolatus. It is therefore essential to detect these characteristic pulses when monitoring of herbicide concentrations are conducted in rivers. PMID:25499055

  7. Biosorption of strontium from simulated nuclear wastewater by Scenedesmus spinosus under culture conditions: adsorption and bioaccumulation processes and models.

    PubMed

    Liu, Mingxue; Dong, Faqin; Kang, Wu; Sun, Shiyong; Wei, Hongfu; Zhang, Wei; Nie, Xiaoqin; Guo, Yuting; Huang, Ting; Liu, Yuanyuan

    2014-06-01

    Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately 10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions. PMID:24919131

  8. Biosorption of Strontium from Simulated Nuclear Wastewater by Scenedesmus spinosus under Culture Conditions: Adsorption and Bioaccumulation Processes and Models

    PubMed Central

    Liu, Mingxue; Dong, Faqin; Kang, Wu; Sun, Shiyong; Wei, Hongfu; Zhang, Wei; Nie, Xiaoqin; Guo, Yuting; Huang, Ting; Liu, Yuanyuan

    2014-01-01

    Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions. PMID:24919131

  9. Effects of linear alkylbenzene sulfonate (LAS) on the interspecific competition between Microcystis and Scenedesmus.

    PubMed

    Zhu, Wei; Chen, Huaimin; Guo, Lili; Li, Ming

    2016-08-01

    The widespread use of detergents increases the concentration of surfactant in lakes and reservoirs. High surfactant loads produces toxicity to algae; however, the influence of the increasing surfactant on the competition between algae is not clear. In this paper, different amounts of linear alkylbenzene sulfonate (LAS) were added to test the effects of LAS on the competition between Microcystis aeruginosa and Scenedesmus obliquus under eutrophic condition. In single culture, the growth of S. obliquus was promoted under lower LAS concentrations (1 and 20 mg L(-1)), but cell density of S. obliquus reduced when treated with higher LAS concentration (100 mg L(-1)). The growth of M. aeruginosa was inhibited markedly with 20 and 100 mg L(-1) LAS. Compared with single culture, the result was opposite in co-cultures and the cell density of S. obliquus increased significantly when treated with LAS of 1, 20, and 100 mg L(-1). The specific growth rates of S. obliquus and M. aeruginosa in both cultures were 0.4-0.5 day(-1) and 0.6-0.7 day(-1), respectively, except that the specific growth rate of M. aeruginosa in both cultures treated with 100 mg L(-1) LAS was about 0.2 day(-1). M. aeruginosa dominated over S. obliquus in the co-culture without LAS, while the competition was completely opposite with the addition of 20 mg L(-1) LAS. The growth of S. obliquus treated with 20 mg L(-1) LAS was not affected significantly in single culture but was promoted by 75 % in co-culture. Moreover, the growth of S. obliquus in co-culture treated with 100 mg L(-1) LAS was promoted by more than 97 %. These results suggested that the increasing LAS would overturn the competition of algae in freshwater ecosystems. PMID:27154838

  10. Chromium toxicity on two linked trophic levels. I. Effects of contaminated algae on Daphnia magna.

    PubMed

    Gorbi, G; Corradi, M G

    1993-02-01

    The effects of feeding Daphnia magna on algae (Scenedesmus acutus) pretreated with different concentrations of Cr(VI) were studied. A positive effect on growth and newborn production rate was observed in the daphnids fed on algae exposed to 1 mg/liter Cr(VI). Fecundity and growth were drastically reduced in daphnids fed on algae exposed to 10 mg/liter Cr(VI). Since the algae, cultured in the presence of these two Cr(VI) concentrations, supplied daphnids with similar amounts of chromium, the observed effects on the population dynamics of D. magna were attributed more to alterations of the nutritional value of the algal food, due to the Cr treatment, than to a toxic effect of the metal. PMID:7682919

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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...

  16. Enantioselective toxicities of chiral ionic liquids 1-alkyl-3-methyl imidazolium tartrate on Scenedesmus obliquus.

    PubMed

    Liu, Huijun; Zhang, Xiaoqiang; Dong, Ying; Chen, Caidong; Zhu, Shimin; Ma, Xiangjuan

    2015-12-01

    Ionic liquids (ILs) are being used in various industries during the last few decades, while the good solubility and high stability of ILs may pose a potential threat to the aquatic environment. Effect of chiral ionic liquids (CILs) 1-alkyl-3-methyl imidazolium tartrate (RMIM T) on Scenedesmus obliquus (S.obliquus) was studied. The growth rate inhibition and cell membrane permeability increased with increasing RMIM T concentration and increasing alkyl chain lengths. The IC50 values of D-(-)-tartrate 1-hexyl-3-methyl imidazolium (D-(-)-HMIM T) were 28.30, 12.23,10.15 and 14.41 mg/L, respectively, at 24, 48, 72 and 96h. While that of L-(+)-tartrate 1-hexyl-3-methyl imidazolium (L-(+)-HMIM T) were 15.97, 7.91, 9.43 and 12.04 mg/L respectively. The concentration of chl a, chl b and chl (a+b) decreased with increasing RMIM T concentration. The chlorophyll fluorescence parameters (F0, Fv/Fm, Fv/F0, Y(II), ETR and NPQ) were affected by RMIM T, indicating that the RMIM T will damage the PSII, inhibit the transmission of excitation energy, decrease the efficiency of photosynthesis. The results showed that there were enantioselective toxicity of RMIM T to algae, and the toxicity of L-(+)-RMIM T was greater than that of D-(-)-RMIM T, but the enantioselective difference becomes smaller with increasing exposure time, and with the increasing carbon chain length of cation, indicating that cation properties may have a larger effect on toxicity than anion properties. PMID:26554523

  17. Cultivation of Scenedesmus dimorphus with domestic secondary effluent and energy evaluation for biodiesel production.

    PubMed

    Zhang, S S; Liu, H; Fan, J F; Yu, H

    2015-01-01

    Microalgae cultivation in wastewater has gained significant attention as a cost-saving means for algae-based biofuel production. To evaluate the performance of Scenedesmus dimorphus cultivated in a 100-L continuously operated photobioreactor using domestic secondary effluent (DSE), algal growth, nutrients removal and energy evaluation were conducted in four scenarios. Prior to the application of continuous cultivation, S. dimorphus was grown in a batch operated 1.5-L bubble column photobioreactor to test the growth feasibility and lipids accumulation of S. dimorphus in DSE. The highest biomass achieved in DSE was 244 mg L(-1)with lipid content at 26.06%. Simultaneously, 98.72% of total phosphorus (TP) and 98.04% of total nitrogen (TN) in DSE were removed. Then, S. dimorphus were inoculated in the 100-L continuously operated photobioreactor using BG11, unsterilized DSE, N, P-added DSE and UV-sterilized DSE as the medium, respectively. Results showed that the highest biomass gained were 567, 174, 276 and 198 mg L(-1), respectively. TP removal rates in four scenarios were all above 90%. With adjustment to DSE, the overall TN removal rates increased up to 80%. Finally, energy evaluation demonstrated that although the case of BG11 as the medium provided the most energy production, the case using DSE with N and P supplementation was of the highest net energy rate, suggesting that microalgae cultivation for biodiesel production by DSE is of obvious potential and advantage over the synthesis medium like BG11. PMID:25253291

  18. 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

  19. 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

  20. Scenedesmus dimorphus biofilm: Photoefficiency and biomass production under intermittent lighting

    PubMed Central

    Toninelli, Andrea Efrem; Wang, Junfeng; Liu, Mingshen; Wu, Hong; Liu, Tianzhong

    2016-01-01

    This study investigated the effect of intermittent lighting on the growth performances of a Scenedesmus dimorphus biofilm. Flashing light effect (FLE) is common in traditional suspended cultures of microalgae; yet, publications about this phenomenon, in the context of biofilm cultivation, are scarce. In this work we demonstrate that, thanks to intermittent illumination, it is possible for attached cultivations to fulfill FLE, improve photoefficiency and productivity as well as providing protection from photoinhibition using much lower flashing light frequencies than those usually required with suspended cultures. Medium frequency intermittent lighting (0.1 Hz) guaranteed excellent light integration resulting in 9.13 g m−2 d−1 biomass productivity, which was 8.9% higher than with continuous lighting. Results showed that a light fraction value of 0.5 always improved photoefficiency values as related to continuous light with a 118.8% maximum increase. PMID:27561323

  1. Scenedesmus dimorphus biofilm: Photoefficiency and biomass production under intermittent lighting.

    PubMed

    Toninelli, Andrea Efrem; Wang, Junfeng; Liu, Mingshen; Wu, Hong; Liu, Tianzhong

    2016-01-01

    This study investigated the effect of intermittent lighting on the growth performances of a Scenedesmus dimorphus biofilm. Flashing light effect (FLE) is common in traditional suspended cultures of microalgae; yet, publications about this phenomenon, in the context of biofilm cultivation, are scarce. In this work we demonstrate that, thanks to intermittent illumination, it is possible for attached cultivations to fulfill FLE, improve photoefficiency and productivity as well as providing protection from photoinhibition using much lower flashing light frequencies than those usually required with suspended cultures. Medium frequency intermittent lighting (0.1 Hz) guaranteed excellent light integration resulting in 9.13 g m(-2) d(-1) biomass productivity, which was 8.9% higher than with continuous lighting. Results showed that a light fraction value of 0.5 always improved photoefficiency values as related to continuous light with a 118.8% maximum increase. PMID:27561323

  2. [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

  3. Preparation protocols for high-activity photosystem II membrane particles of green algae and higher plants, pH dependence of oxygen evolution and comparison of the S2-state multiline signal by X-band EPR spectroscopy.

    PubMed

    Schiller, H; Dau, H

    2000-01-01

    Photosystem II (PS II) membrane particles are particularly well suited for various types of spectroscopic investigations on the PS II manganese complex. Here we present: (1) a preparation protocol for PS II membrane particles of higher plants, which yields exceptionally high oxygen-evolution activity due to the use of glycinebetaine as a PS II-stabilizing agent; (2) preparation protocols for highly active PS II membrane particles for the green algae Scenedesmus obliquus and Chlamydomonas reinhardtii; (3) a determination of pH dependence of oxygen evolution for spinach and Scenedesmus; (4) a comparison of the EPR multiline signal observed in the S2-state of green algae and higher plants of PS II membrane particles. A clearly broader type of multiline EPR signal is observed in green algae. PMID:10942078

  4. 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

  5. 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.

  6. Transmission and Accumulation of Nano-TiO2 in a 2-Step Food Chain (Scenedesmus obliquus to Daphnia magna).

    PubMed

    Chen, Jinyuan; Li, Herong; Han, Xiaoqian; Wei, Xiuzhen

    2015-08-01

    The recent increase in nanomaterial usage has led to concerns surrounding its health risks and environmental impact. The food chain is an important pathway for high-trophic-level organisms absorbing and enriching nanomaterials. Our study therefore simulated nanometer titanium dioxide (nano-TiO2) transfer along a 2-step food chain, from the unicellular alga Scenedesmus obliquus to the water flea Daphnia magna. We also explored the effect of sodium dodecyl benzene sulfonate (SDBS) on nano-TiO2 bioavailability. A suspension of 10 mg/L nano-TiO2 was optimally dispersed in aqueous solutions by 5 mg/L SDBS. After 72 h, S. obliquus growth was not significantly affected by 10 mg/L nano-TiO2, 5 mg/L SDBS and their mixed suspension. SDBS not only improved nano-TiO2 stability in water, but also increased its uptake in S. obliquus and enhanced its accumulation in D. magna. Our study suggests that nano-TiO2 is mildly toxic to S. obliquus, and can be transferred along the aquatic food chain with a biomagnification effect. PMID:26091814

  7. Effect of Nano-Al2O3 on the Toxicity and Oxidative Stress of Copper towards Scenedesmus obliquus

    PubMed Central

    Li, Xiaomin; Zhou, Suyang; Fan, Wenhong

    2016-01-01

    Nano-Al2O3 has been widely used in various industries; unfortunately, it can be released into the aquatic environment. Although nano-Al2O3 is believed to be of low toxicity, it can interact with other pollutants in water, such as heavy metals. However, the interactions between nano-Al2O3 and heavy metals as well as the effect of nano-Al2O3 on the toxicity of the metals have been rarely investigated. The current study investigated copper toxicity in the presence of nano-Al2O3 towards Scenedesmus obliquus. Superoxide dismutase activity and concentration of glutathione and malondialdehyde in cells were determined in order to quantify oxidative stress in this study. Results showed that the presence of nano-Al2O3 reduced the toxicity of Cu towards S. obliquus. The existence of nano-Al2O3 decreased the growth inhibition of S. obliquus. The accumulation of copper and the level of oxidative stress in algae were reduced in the presence of nano-Al2O3. Furthermore, lower copper accumulation was the main factor that mitigated copper toxicity with the addition of nano-Al2O3. The decreased copper uptake could be attributed to the adsorption of copper onto nanoparticles and the subsequent decrease of available copper in water. PMID:27294942

  8. A toxicokinetic study of specifically acting and reactive organic chemicals for the prediction of internal effect concentrations in Scenedesmus vacuolatus.

    PubMed

    Vogs, Carolina; Kühnert, Agnes; Hug, Christine; Küster, Eberhard; Altenburger, Rolf

    2015-01-01

    The toxic potency of chemicals is determined by using the internal effect concentration by accounting for differences in toxicokinetic processes and mechanisms of toxic action. The present study examines toxicokinetics of specifically acting and reactive chemicals in the green algae Scenedesmus vacuolatus by using an indirect method. Concentration depletion in the exposure medium was measured for chemicals of lower (log KOW  < 3: isoproturon, metazachlor, paraquat) and moderate (log KOW 4-5: irgarol, triclosan, N-phenyl-2-naphthylamine) hydrophobicity at 7 to 8 time points over 240 min or 360 min. Uptake and overall elimination rates were estimated by fitting a toxicokinetic model to the observed concentration depletions. The equilibrium of exposure concentrations was reached within minutes to hours or was even not observed within the exposure time. The kinetics of bioconcentration cannot be explained by the chemical's hydrophobicity only, but influential factors such as ionization of chemicals, the ion trapping mechanism, or the potential susceptibility for biotransformation are discussed. Internal effect concentrations associated with 50% inhibition of S. vacuolatus reproduction were predicted by linking the bioconcentration kinetics to the effect concentrations and ranged from 0.0480 mmol/kg wet weight to 7.61 mmol/kg wet weight for specifically acting and reactive chemicals. Knowing the time-course of the internal effect concentration may promote an understanding of toxicity processes such as delayed toxicity, carry-over toxicity, or mixture toxicity in future studies. PMID:25263251

  9. Photosynthesis of Scenedesmus obliquus in outdoor open thin-layer cascade system in high and low CO2 in Belgium.

    PubMed

    de Marchin, Thomas; Erpicum, Michel; Franck, Fabrice

    2015-12-10

    Two outdoor open thin-layer cascade systems operated as batch cultures with the alga Scenedesmus obliquus were used to compare the productivity and photosynthetic acclimations in control and CO2 supplemented cultures in relation with the outdoor light irradiance. We found that the culture productivity was limited by CO2 availability. In the CO2 supplemented culture, we obtained a productivity of up to 24gdwm(-2)day(-1) and found a photosynthetic efficiency (value based on the PAR solar radiation energy) of up to 5%. In the CO2 limited culture, we obtained a productivity of up to 10gdwm(-2)day(-1) while the photosynthetic efficiency was up to 3.3% and decreased to 2.1% when the integrated daily PAR increased. Fluorescence and oxygen evolution measurements showed that ETR and oxygen evolution light saturation curves, as well as light-dependent O2 uptake were similar in algal samples from both cultures when the CO2 limitation was removed. In contrast, we found that CO2 limitation conducted to a decreased PSII photochemical efficiency and an increased light-induced heat-dissipation in the control culture compared to the CO2 supplemented culture. These features are in line with a lower light use efficiency and may therefore contribute to the lower productivity observed in absence of CO2 supplementation in outdoor mass cultures of S. obliquus. PMID:26232563

  10. Effect of Nano-Al₂O₃ on the Toxicity and Oxidative Stress of Copper towards Scenedesmus obliquus.

    PubMed

    Li, Xiaomin; Zhou, Suyang; Fan, Wenhong

    2016-01-01

    Nano-Al₂O₃ has been widely used in various industries; unfortunately, it can be released into the aquatic environment. Although nano-Al₂O₃ is believed to be of low toxicity, it can interact with other pollutants in water, such as heavy metals. However, the interactions between nano-Al₂O₃ and heavy metals as well as the effect of nano-Al₂O₃ on the toxicity of the metals have been rarely investigated. The current study investigated copper toxicity in the presence of nano-Al₂O₃ towards Scenedesmus obliquus. Superoxide dismutase activity and concentration of glutathione and malondialdehyde in cells were determined in order to quantify oxidative stress in this study. Results showed that the presence of nano-Al₂O₃ reduced the toxicity of Cu towards S. obliquus. The existence of nano-Al₂O₃ decreased the growth inhibition of S. obliquus. The accumulation of copper and the level of oxidative stress in algae were reduced in the presence of nano-Al₂O₃. Furthermore, lower copper accumulation was the main factor that mitigated copper toxicity with the addition of nano-Al₂O₃. The decreased copper uptake could be attributed to the adsorption of copper onto nanoparticles and the subsequent decrease of available copper in water. PMID:27294942

  11. 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

  12. Effect of subcellular distribution on nC₆₀ uptake and transfer efficiency from Scenedesmus obliquus to Daphnia magna.

    PubMed

    Chen, Qiqing; Hu, Xialin; Yin, Daqiang; Wang, Rui

    2016-06-01

    The potential uptake and trophic transfer ability of nanoparticles (NPs) in aquatic organisms have not been well understood yet. There has been an increasing awareness of the subcellular fate of NPs in organisms, but how the subcellular distribution of NPs subsequently affects the trophic transfer to predator remains to be answered. In the present study, the food chain from Scenedesmus obliquus to Daphnia magna was established to simulate the trophic transfer of fullerene aqueous suspension (nC60). The nC60 contaminated algae were separated into three fractions: cell wall (CW), cell organelle (CO), and cell membrane (CM) fractions, and we investigated the nC60 uptake amounts and trophic transfer efficiency to the predator through dietary exposure to algae or algal subcellular fractions. The nC60 distribution in CW fraction of S. obliquus was the highest, following by CO and CM fractions. nC60 uptake amounts in D. magna were found to be mainly relative to the NPs' distribution in CW fraction and daphnia uptake ability from CW fraction, whereas the nC60 trophic transfer efficiency (TE) were mainly in accordance with the transfer ability of NPs from the CO fraction. CW fed group possessed the highest uptake amount, followed by CO and CM fed groups, but the presence of humic acid (HA) significantly decreased the nC60 uptake from CW fed group. The CO fed groups acquired high TE values for nC60, while CM fed groups had low TE values. Moreover, even though CW fed group had a high TE value; it decreased significantly with the presence of HA. This study contributes to the understanding of fullerene NPs' dietary exposure to aquatic organisms, suggesting that NPs in different food forms are not necessarily equally trophically available to the predator. PMID:26946286

  13. Salicylhydroxamic acid (SHAM) inhibition of the DIC-pump in unicellular algae

    SciTech Connect

    Goyal, A.; Tolbert, N.E. )

    1989-04-01

    SHAM at 1 or 2 mM inhibits dissolved inorganic carbon (DIC) concentrating mechanisms in unicellular green algae as measured by photosynthetic oxygen evolution or by {sup 14}C-inorganic carbon uptake (using silicone oil centrifugation techniques). This inhibition was reversed by high levels of DIC whereby the cells do not require the concentrating mechanism. SHAM inhibited the DIC-pump, which uses external CO{sub 2}, in three species of algae, Dunaliella tertiolecta, Chlamydomonas reinhardtii, and Scenedesmus obliquus when adapted to low CO{sub 2} and assayed around neutral pH. Scenedesmus adapted to air at pH 9.0 to use external HCO{sub 3}{sup {minus}} were not affected by SHAM. It is important to establish low optimum concentrations of SHAM, which varied with the algal species. The mechanism of SHAM inhibition of the CO{sub 2} concentrating process is unknown. SHAM inhibits alternative respiration in these algae, but SHAM may also inhibit other reactions involving H{sup +} gradients or transporters associated with the DIC-pump.

  14. Carbon dioxide fixation and lipid storage by Scenedesmus obtusiusculus.

    PubMed

    Toledo-Cervantes, Alma; Morales, Marcia; Novelo, Eberto; Revah, Sergio

    2013-02-01

    An indigenous microalga was isolated from the springs in Cuatro Ciénegas, México. It was morphologically identified as Scenedesmus obtusiusculus and cultivated in bubble-column photobioreactors in batch operation mode. This microalga grows at 10% of carbon dioxide (CO(2)) showing a maximum CO(2) fixation rate of 970gm(-3)d(-1). The microalga, without any nutrient limitation, contained 20% of nonpolar lipids with a biomass productivity of 500gm(-3)d(-1) and a maximum biomass concentration of around 6,000gm(-3) at 5% CO(2) and irradiance of 134μmolm(-2)s(-1). Furthermore, it was observed that the microalga stored 55.7% of nonpolar lipids when 5% CO(2) was fed at 0.8vvm and 54.7μmolm(-2)s(-1) under nitrogen starvation. The lipid profile included C16:0, C18:0, C18:1n9t, C18:1n9c, C18:3n6 with a productivity of 200g lipid m(-3)d(-1). Therefore, the microalga may have biotechnological potential producing lipids for biodiesel. PMID:23334023

  15. Scenedesmus quadricauda for Nutrient Removal and Lipid Production in Wastewater.

    PubMed

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

    2015-12-01

    Scenedesmus quadricauda, a local freshwater microalga, was used to treat primary settled and filtrate wastewater and to produce algal lipid. For the primary settled wastewater, the maximum biomass concentrations of acclimated and unacclimated microalgae were 0.995 g/L and 0.940 g/L, respectively. Over 90% orthophosphate and 95% ammonia nitrogen in the acclimated and unacclimated cultures, respectively, were removed after five days. The lipid contents of the microalgae were higher than 13% in all cultures. The highest growth rate occurred in the 25% filtrate culture. Over 80% phosphate was removed under the 25% and 50% filtrate cultures within six days, while over 90% ammonia nitrogen was removed within five days under both conditions. The lipid content was the highest (18.1%) under the 50% filtrate condition. C16:0, C18:2n6, and C18:3n3 were dominant fatty acids. In conclusion, S. quadricauda is a viable candidate for wastewater treatment and lipid production. PMID:26652116

  16. 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 ...

  17. 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.

  18. 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

  19. Effects of artemisinin sustained-release granules on mixed alga growth and microcystins production and release.

    PubMed

    Ni, Lixiao; Li, Danye; Hu, Shuzhen; Wang, Peifang; Li, Shiyin; Li, Yiping; Li, Yong; Acharya, Kumud

    2015-12-01

    To safely and effectively apply artemisinin sustained-release granules to control and prevent algal water-blooms, the effects of artemisinin and its sustained-release granules on freshwater alga (Scenedesmus obliquus (S. obliquus) and Microcystis aeruginosa (M. aeruginosa)), as well as the production and release of microcystins (MCs) were studied. The results showed that artemisinin sustained-release granules inhibited the growth of M. aeruginosa (above 95% IR) and S. obliquus (about 90% IR), with M. aeruginosa more sensitive. The artemisinin sustained-release granules had a longer inhibition effect on growth of pure algae and algal coexistence than direct artemisinin dosing. The artemisinin sustained-release granules could decrease the production and release of algal toxins due to the continued stress of artemisinin released from artemisinin sustained-release granules. There was no increase in the total amount of MC-LR in the algal cell culture medium. PMID:26432265

  20. Inhibition of three algae species using chemicals released from barley straw.

    PubMed

    Murray, D; Jefferson, B; Jarvis, P; Parsons, S A

    2010-04-01

    Algal blooms are a significant problem in the UK, particularly in water sources that supply potable water treatment works. A wide range of methods to control algae have been tested and, whilst many are effective, they all have disadvantages. The use of barley straw to control algal growth in reservoirs is one option that is gaining popularity, but little is known about its mode of action. One suggested mechanism is that, as the straw is broken down, algastatic chemicals such as phenolics are released. Here we have used an algae inhibition test to evaluate the effect of chemicals reported to be released from straw on three common algal species: Chlorella vulgaris, Microcystis aeruginosa and Scenedesmus subspicatus. It was shown that, of the chemicals assessed, many produced an algastatic effect on the growth of the three algal species tested, with 2 phenyl-phenol being the most effective, whilst p-cresol and benzaldehyde were shown to be effective at concentrations similar to those that have been reported downstream of rotted straw. Scenedesmus subspicatus proved to be much more resistant to the chemicals tested than the other species. PMID:20450120

  1. Biodiesel Production by the Green Microalga Scenedesmus obliquus in a Recirculatory Aquaculture System

    PubMed Central

    Mandal, Shovon

    2012-01-01

    Biodiesel production was examined with Scenedesmus obliquus in a recirculatory aquaculture system with fish pond discharge and poultry litter to couple with waste treatment. Lipid productivity of 14,400 liter ha−1 year−1 was projected with 11 cultivation cycles per year. The fuel properties of the biodiesel produced adhered to Indian and international standards. PMID:22660702

  2. 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.

  3. Superior triacylglycerol (TAG) accumulation in starchless mutants of Scenedesmus obliquus: (II) evaluation of TAG yield and productivity in controlled photobioreactors

    PubMed Central

    2014-01-01

    Background Many microalgae accumulate carbohydrates simultaneously with triacylglycerol (TAG) upon nitrogen starvation, and these products compete for photosynthetic products and metabolites from the central carbon metabolism. As shown for starchless mutants of the non-oleaginous model alga Chlamydomonas reinhardtii, reduced carbohydrate synthesis can enhance TAG production. However, these mutants still have a lower TAG productivity than wild-type oleaginous microalgae. Recently, several starchless mutants of the oleaginous microalga Scenedesmus obliquus were obtained which showed improved TAG content and productivity. Results The most promising mutant, slm1, is compared in detail to wild-type S. obliquus in controlled photobioreactors. In the slm1 mutant, the maximum TAG content increased to 57 ± 0.2% of dry weight versus 45 ± 1% in the wild type. In the wild type, TAG and starch were accumulated simultaneously during initial nitrogen starvation, and starch was subsequently degraded and likely converted into TAG. The starchless mutant did not produce starch and the liberated photosynthetic capacity was directed towards TAG synthesis. This increased the maximum yield of TAG on light by 51%, from 0.144 ± 0.004 in the wild type to 0.217 ± 0.011 g TAG/mol photon in the slm1 mutant. No differences in photosynthetic efficiency between the slm1 mutant and the wild type were observed, indicating that the mutation specifically altered carbon partitioning while leaving the photosynthetic capacity unaffected. Conclusions The yield of TAG on light can be improved by 51% by using the slm1 starchless mutant of S. obliquus, and a similar improvement seems realistic for the areal productivity in outdoor cultivation. The photosynthetic performance is not negatively affected in the slm1 and the main difference with the wild type is an improved carbon partitioning towards TAG. PMID:24883102

  4. Effect of ultraviolet radiation on photosynthesis, biomass, and fatty acid content and profile of a Scenedesmus rubescens-like microalga.

    PubMed

    Li, Ping; Lin, Junda

    2012-05-01

    The effects of ultraviolet radiation (UVR) and nitrogen (NaNO(3)) concentration on photosynthesis, biomass, and fatty acid content and profile of a Scenedesmus rubescens-like microalga were measured in an outdoor 8-day culture study. UV-induced photoinhibition decreased from 42.6% to 3.5%, in the presence of 75 mg/L NaNO(3) (HN) and from 52.9% to 22.6% in the presence of 7.5mg/L NaNO(3) (LN) nitrogen concentration, respectively. The concentrations of UV-absorbing compounds increased 4.3 and 4.9 times under HN and LN, respectively. Biomass accumulation was suppressed (10.7%) by UVR under HN, but not under LN conditions. Carotenoid content decreased from 1.05 ± 0.06 to 0.96 ± 0.15 (with UV radiation) and to 0.91 ± 0.07 (without UV radiation), respectively, under HN, while it decreased to 0.05 ± 0.04 (with UV radiation) and to 0.11 ± 0.08 (without UV radiation), respectively, under LN. The content of C18:1n9 fatty acids increased by about 430%, whereas that of C18:3n3 decreased by about 65% in both radiation treatments during nitrogen starvation. The results showed that the absence of UVR screening does not change the fatty acid content and profile of S. rubescens-like algae cultivated outdoors under HN and LN conditions. PMID:22365715

  5. 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

  6. Modelling the effects of pulse exposure of several PSII inhibitors on two algae.

    PubMed

    Copin, Pierre-Jean; Chèvre, Nathalie

    2015-10-01

    Subsequent to crop application and during precipitation events, herbicides can reach surface waters in pulses of high concentrations. These pulses can exceed the Annual Average Environmental Quality Standards (AA-EQS), defined in the EU Water Framework Directive, which aims to protect the aquatic environment. A model was developed in a previous study to evaluate the effects of pulse exposure for the herbicide isoproturon on the alga Scenedesmus vacuolatus. In this study, the model was extended to other substances acting as photosystem II inhibitors and to other algae. The measured and predicted effects were equivalent when pulse exposure of atrazine and diuron were tested on S. vacuolatus. The results were consistent for isoproturon on the alga Pseudokirchneriella subcapitata. The model is thus suitable for the effect prediction of phenylureas and triazines and for the algae used: S. vacuolatus and P. subcapitata. The toxicity classification obtained from the dose-response curves (diuron>atrazine>isoproturon) was conserved for the pulse exposure scenarios modelled for S. vacuolatus. Toxicity was identical for isoproturon on the two algae when the dose-response curves were compared and also for the pulse exposure scenarios. Modelling the effects of any pulse scenario of photosystem II inhibitors on algae is therefore feasible and only requires the determination of the dose-response curves of the substance and growth rate of unexposed algae. It is crucial to detect the longest pulses when measurements of herbicide concentrations are performed in streams because the model showed that they principally affect the cell density inhibition of algae. PMID:26011414

  7. Evaluation of the measurement of Cu(II) bioavailability in complex aqueous media using a hollow-fiber supported liquid membrane device (HFSLM) and two microalgae species (Pseudokirchneriella subcapitata and Scenedesmus acutus).

    PubMed

    Rodríguez-Morales, Erik A; Rodríguez de San Miguel, Eduardo; de Gyves, Josefina

    2015-11-01

    The environmental bioavailability of copper was determined using a hollow-fiber supported liquid membrane (HFSLM) device as a chemical surrogate and two microalgae species (Scenedesmus acutus and Pseudokirchneriella subcapitata). Several experimental conditions were studied: pH, the presence of organic matter, inorganic anions, and concomitant cations. The results indicated a strong relationship between the response given by the HFSLM and the microalgae species with free copper concentrations measured by an ion selective electrode (ISE), in accordance with the free-ion activity model (FIAM). A significant positive correlation was evident when comparing the bioavailability results measured by the HFSLM and the S. acutus microalga species, showing that the synthetic device may emulate biological uptake and, consequently, be used as a chemical test for bioavailability measurements using this alga as a biological reference. PMID:26431807

  8. [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

  9. 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.

  10. 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 ...

  11. sup 1 H NMR studies of plastocyanin from Scenedesmus obliquus: Complete sequence-specific assignment, secondary structure analysis, and global fold

    SciTech Connect

    Moore, J.M.; Chazin, W.J.; Wright, P.E. ); Powls, R. )

    1988-10-04

    Two-dimensional {sup 1}H NMR methods have been used to make sequence-specific resonance assignments for the 97 amino acid residues of the plastocyanin from the green alga Scenedesmus obliquus. Assignments were obtained for all backbone protons and the majority of the side-chain protons. Spin system identification relied heavily on the observation of relayed connectivities to the backbone amide proton. Sequence-specific assignments were made by using the sequential assignment procedure. During this process, an extra valine residue was identified that had not been detected in the original amino acid sequence. Elements of regular secondary structure were identified from characteristic NOE connectivities between backbone protons, coupling constant values, and the observation of slowly exchanging amide protons. The protein in solution contains eight {beta}-strands, one short segment of helix, five reverse turns, and five loops. The {beta}-strands may be arranged into two {beta}sheets on the basis of extensive cross-strand NOE connectivities. The chain-folding topology determined from the NMR experiments is that of a Greek key {beta}-barrel and is similar to that observed for French bean plastocyanin in solution and poplar plastocyanin in the crystalline state. While the overall structures are similar, several differences in local structure between the S. obliquus and higher plant plastocyanins have been identified.

  12. Phenotypic plasticity in Scenedesmus incrassatulus (Chlorophyceae) in response to heavy metals stress.

    PubMed

    Peña-Castro, Julián Mario; Martínez-Jerónimo, Fernando; Esparza-García, Fernando; Cañizares-Villanueva, Rosa Olivia

    2004-12-01

    The microalgae genus Scenedesmus is commonly found in freshwater bodies, wastewater facilities and water polluted with heavy metals. Phenotypic plasticity in Scenedesmus has been documented in response to a wide variety of conditions; however, heavy metals have not been comprehensively documented as phenotypic plasticity inducers. In this study, we report the phenotypic plasticity of Scenedesmus incrassatulus (a non-spiny, four-cell coenobium forming species) in response to EC(50) value of copper, cadmium and hexavalent chromium. S. incrassatulus was grown in batch cultures in the presence of each metal. Chlorophyll-a content, cell size, parameters derived from the schematic energy-flux model for photosystem II, and morphotype expressions were recorded. Divalent cation metals induced unicellular forms, and hexavalent chromium produced out-of-shape coenobia corresponding to various stages of autospore formation. The changes induced by divalent metals were interpreted as phenotypic plasticity, because they were always associated to population doublings and were reversible when toxicant pressure was removed (only for Cu). Copper was the best inductor of unicellular forms and also affected significantly all the photosynthetic parameters measured. The developed morphotypes could confer ecological advantages to S. incrassatulus in metal stressed environments. PMID:15519408

  13. Laccase-like enzyme activities from chlorophycean green algae with potential for bioconversion of phenolic pollutants.

    PubMed

    Otto, Benjamin; Beuchel, Carl; Liers, Christiane; Reisser, Werner; Harms, Hauke; Schlosser, Dietmar

    2015-06-01

    In order to explore the abundance and potential environmental functions of green algal laccases, we screened various algae for extracellular laccase-like activities, characterized basic features of these activities in selected species and exemplarily studied the transformation of environmental pollutants and complex natural compounds by the laccase of Tetracystis aeria. Oxidation of the classical laccase substrate ABTS was found to be widespread in chlorophycean algae. The oxidation activity detected in members of the 'Scenedesmus' clade was caused by an unknown thermostable low-molecular-mass compound. In contrast, species of the Moewusinia, including Chlamydomonas moewusii and T. aeria, excreted putative 'true' laccases. Phenolic substrates were oxidized by these enzymes optimally at neutral to alkaline pH. The Tetracystis laccase efficiently transformed bisphenol A, 17α-ethinylestradiol, nonylphenol and triclosan in the presence of ABTS as redox mediator, while anthracene, veratrylalcohol and adlerol were not attacked. Lignosulfonate and humic acid underwent slight (de)polymerization reactions in the presence of the laccase and mediator(s), probably involving the oxidation of phenolic constituents. Possible natural functions of the enzymes, such as the synthesis of complex polymers or detoxification processes, may assist the survival of the algae in adverse environments. In contaminated surface waters, laccase-producing green algae might contribute to the environmental breakdown of phenolic pollutants. PMID:25926529

  14. Time-Dependent Effects in Algae for Chemicals with Different Adverse Outcome Pathways: A Novel Approach.

    PubMed

    Vogs, Carolina; Altenburger, Rolf

    2016-07-19

    Chemicals affect unicellular algae as a result of toxicokinetic and toxicodynamic processes. The internal concentration of chemicals in algae cells typically reaches equilibrium within minutes, while damage cumulatively increases over hours. The time gap between the steady state of internal exposure and damage development is thus suspected to span up to hours, mainly due to toxicodynamic processes. The quantification of rate-limited toxicodynamic processes, aggregated as a progressive effect from an initiating molecular event through biological key events toward the adverse outcome on algae growth inhibition, might discriminate between different adverse outcome pathways (AOPs). To support our hypothesis, we selected six chemicals according to different physicochemical properties and three distinctly dissimilar AOPs. The time courses of internal concentrations were linked to the observed affected Scenedesmus vacuolatus growth using toxicokinetic-toxicodynamic modeling. Effects on cell growth were explained by effect progression and not by the time to reach internal equilibrium concentration. Effect progression rates ranged over 6 orders of magnitude for all chemicals but varied by less than 1 order of magnitude within similar AOP (photosystem II inhibitors > reactive chemicals > lipid biosynthesis inhibitors), meaning that inhibitors of photosystem II advance an effect toward algae growth fastest compared to reactive chemicals and inhibitors of lipid biosynthesis. PMID:27149222

  15. 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

  16. 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...

  17. 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

  18. 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).

  19. 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.

  20. 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

  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. 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

  3. Salicylhydroxamic acid (SHAM) inhibition of the dissolved inorganic carbon concentrating process in unicellular green algae

    SciTech Connect

    Goyal, A.; Tolbert, N.E. )

    1990-03-01

    Rates of photosynthetic O{sub 2} evolution, for measuring K{sub 0.5}(CO{sub 2} + HCO{sub 3}{sup {minus}}) at pH 7, upon addition of 50 micromolar HCO{sub 3}{sup {minus}} to air-adapted Chlamydomonas, Dunaliella, or Scenedesmus cells, were inhibited up to 90% by the addition of 1.5 to 4.0 millimolar salicylhydroxamic acid (SHAM) to the aqueous medium. The apparent K{sub i}(SHAM) for Chlamydomonas cells was about 2.5 millimolar, but due to low solubility in water effective concentrations would be lower. Salicylhydroxamic acid did not inhibit oxygen evolution or accumulation of bicarbonate by Scenedesmus cells between pH 8 to 11 or by isolated intact chloroplasts from Dunaliella. Thus, salicylhydroxamic acid appears to inhibit CO{sub 2} uptake, whereas previous results indicate that vanadate inhibits bicarbonate uptake. These conclusions were confirmed by three test procedures with three air-adapted algae at pH 7. Salicylhydroxamic acid inhibited the cellular accumulation of dissolved inorganic carbon, the rate of photosynthetic O{sub 2} evolution dependent on low levels of dissolved inorganic carbon (50 micromolar NaHCO{sub 3}), and the rate of {sup 14}CO{sub 2} fixation with 100 micromolar ({sup 14}C)HCO{sub 3}{sup {minus}}. Salicylhydroxamic acid inhibition of O{sub 2} evolution and {sup 14}CO{sub 2}-fixation was reversed by higher levels of NaHCO{sub 3}. Thus, salicylhydroxamic acid inhibition was apparently not affecting steps of photosynthesis other than CO{sub 2} accumulation. Although salicylhydroxamic acid is an inhibitor of alternative respiration in algae, it is not known whether the two processes are related.

  4. 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

  5. Bioethanol production from Scenedesmus obliquus sugars: the influence of photobioreactors and culture conditions on biomass production.

    PubMed

    Miranda, J R; Passarinho, P C; Gouveia, L

    2012-10-01

    A closed-loop vertical tubular photobioreactor (PBR), specially designed to operate under conditions of scarce flat land availability and irregular solar irradiance conditions, was used to study the potential of Scenedesmus obliquus biomass/sugar production. The results obtained were compared to those from an open-raceway pond and a closed-bubble column. The influence of the type of light source and the regime (natural vs artificial and continuous vs light/dark cycles) on the growth of the microalga and the extent of the sugar accumulation was studied in both PBRs. The best type of reactor studied was a closed-loop PBR illuminated with natural light/dark cycles. In all the cases, the relationship between the nitrate depletion and the sugar accumulation was observed. The microalga Scenedesmus was cultivated for 53 days in a raceway pond (4,500 L) and accumulated a maximum sugar content of 29 % g/g. It was pre-treated for carrying out ethanol fermentation assays, and the highest ethanol concentration obtained in the hydrolysate fermented by Kluyveromyces marxianus was 11.7 g/L. PMID:22899495

  6. Increase of chromium tolerance in Scenedesmus acutus after sulfur starvation: Chromium uptake and compartmentalization in two strains with different sensitivities to Cr(VI).

    PubMed

    Marieschi, M; Gorbi, G; Zanni, C; Sardella, A; Torelli, A

    2015-10-01

    In photosynthetic organisms sulfate constitutes the main sulfur source for the biosynthesis of GSH and its precursor Cys. Hence, sulfur availability can modulate the capacity to cope with environmental stresses, a phenomenon known as SIR/SED (Sulfur Induced Resistance or Sulfur Enhanced Defence). Since chromate may compete for sulfate transport into the cells, in this study chromium accumulation and tolerance were investigated in relation to sulfur availability in two strains of the unicellular green alga Scenedesmus acutus with different Cr-sensitivities. Paradoxically, sulfur deprivation has been demonstrated to induce a transient increase of Cr-tolerance in both strains. Sulfur deprivation is known to enhance the sulfate uptake/assimilation pathway leading to important consequences on Cr-tolerance: (i) reduced chromate uptake due to the induction of high affinity sulfate transporters (ii) higher production of cysteine and GSH which can play a role both through the formation of unsoluble complexes and their sequestration in inert compartments. To investigate the role of the above mentioned mechanisms, Cr accumulation in total cells and in different cell compartments (cell wall, membranes, soluble and miscellaneous fractions) was analyzed in both sulfur-starved and unstarved cells. Both strains mainly accumulated chromium in the soluble fraction, but the uptake was higher in the wild-type. In this type a short period of sulfur starvation before Cr(VI) treatment lowered chromium accumulation to the level observed in the unstarved Cr-tolerant strain, in which Cr uptake seems instead less influenced by S-starvation, since no significant decrease was observed. The increase in Cr-tolerance following S-starvation seems thus to rely on different mechanisms in the two strains, suggesting the induction of a mechanism constitutively active in the Cr-tolerant strain, maybe a high affinity sulfate transporter also in the wild-type. Changes observed in the cell wall and

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Biodiesel production from Scenedesmus bijuga grown in anaerobically digested food wastewater effluent.

    PubMed

    Shin, Dong Yun; Cho, Hyun Uk; Utomo, Joseph Christian; Choi, Yun-Nam; Xu, Xu; Park, Jong Moon

    2015-05-01

    Microalgae, Scenedesmus bijuga, was cultivated in anaerobically digested food wastewater effluent (FWE) to treat the wastewater and produce biodiesel simultaneously. Three different mixing ratios with municipal wastewater were compared for finding out proper dilution ratio in biodiesel production. Of these, 1/20 diluted FWE showed the highest biomass production (1.49 g/L). Lipid content was highest in 1/10 diluted FWE (35.06%), and the lipid productivity showed maximum value in 1/20 diluted FWE (15.59 mg/L/d). Nutrient removal was also measured in the cultivation. FAME compositions were mainly composed of C16-C18 (Over 98.94%) in S. bijuga. In addition, quality of FAMEs was evaluated by Cetane Number (CN) and Bis-allylic Position Equivalent (BAPE). PMID:25466996

  12. Graphene oxide alleviates the ecotoxicity of copper on the freshwater microalga Scenedesmus obliquus.

    PubMed

    Hu, Changwei; Hu, Naitao; Li, Xiuling; Zhao, Yongjun

    2016-10-01

    The extensive industrial application of graphene oxide (GO), has increased its exposure risk to various aquatic organisms and its potential to affect the toxicity of other environmental pollutants. In this study, we investigated the combined toxicity of GO and copper on the freshwater microalga Scenedesmus obliquus, using the MIXTOX model. The effects of low concentration (1mg/L) exposure to GO were investigated with environmentally relevant concentrations of copper by using a 12-d subacute toxicity test, with pre- and post-GO treatment. Results showed that there were significant antagonistic effects between GO and copper on S. obliquus, and GO was found to reduce ecotoxicity of copper even at low and environmentally relevant concentrations (1mg/L). PMID:27376350

  13. Growth, photosynthetic and respiratory responses to sub-lethal copper concentrations in Scenedesmus incrassatulus (Chlorophyceae).

    PubMed

    Perales-Vela, Hugo Virgilio; González-Moreno, Sergio; Montes-Horcasitas, Carmen; Cañizares-Villanueva, Rosa Olivia

    2007-05-01

    In the present paper we investigated the effects of sub-lethal concentrations of Cu2+ in the growth and metabolism of Scenedesmus incrassatulus. We found that the effect of Cu2+ on growth, photosynthetic pigments (chlorophylls and carotenoids) and metabolism do not follow the same pattern. Photosynthesis was more sensitive than respiration. The analysis of chlorophyll a fluorescence transient shows that the effect of sub-lethal Cu2+ concentration in vivo, causes a reduction of the active PSII reaction centers and the primary charge separation, decreasing the quantum yield of PSII, the electron transport rate and the photosynthetic O2 evolution. The order of sensitivity found was: Growth>photosynthetic pigments content=photosynthetic O2 evolution>photosynthetic electron transport>respiration. The uncoupled relationship between growth and metabolism is discussed. PMID:17267014

  14. 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.

  15. Elicitation of the most important structural properties of ionic liquids affecting ecotoxicity in limnic green algae; a QSAR approach.

    PubMed

    Izadiyan, Parisa; Fatemi, M H; Izadiyan, Mahsa

    2013-01-01

    Many ionic liquids are soluble in water and their impact on the aquatic environment has to be evaluated. However, due to the large number of ionic liquids and lack of experimental data, it is necessary to develop estimation procedures in order to reduce the materials and time consumption. In this study using multilayer perceptron neural network (MLP), ant colony optimization (ACO) and multiple linear regression (MLR) strategies, good predictive quantitative structure-activity relationships (QSAR) models were introduced and structural parameters affecting ecotoxicity of ionic liquids in limnic green algae (Scenedesmus vacuolatus) were revealed. Moreover, principal component analysis (PCA) and cluster analysis (CA) approaches were also applied to visualize any possible patterns or relationships among ionic liquids data. It was revealed that selected descriptors of the MLR model are also capable of clustering ionic liquids according to their four level of toxicity. PMID:23107477

  16. Influences of surface coating, UV irradiation and magnetic field on the algae removal using magnetite nanoparticles.

    PubMed

    Ge, Shijian; Agbakpe, Michael; Wu, Zhiyi; Kuang, Liyuan; Zhang, Wen; Wang, Xianqin

    2015-01-20

    Magnetophoretic separation is a promising and sustainable technology for rapid algal separation or removal from water. This work demonstrated the application of magnetic magnetite nanoparticles (MNPs) coated with a cationic polymer, polyethylenimine (PEI), toward the separation of Scenedesmus dimorphus from the medium broth. The influences of surface coating, UV irradiation, and magnetic field on the magnetophoretic separation were systematically examined. After PEI coating, zeta potential of MNPs shifted from −7.9 ± 2.0 to +39.0 ± 3.1 mV at a pH of 7.0, which improved MNPs-algae interaction and helped reduce the dose demand of MNPs (e.g., from 0.2 to 0.1 g·g(–1) while the harvesting efficiency (HE) of over 80% remained unchanged). The extended Derjaguin–Landau–Verwey–Overbeek theory predicted a strong attractive force between PEI-coated MNPs and algae, which supported the improved algal harvesting. Moreover, the HE was greater under the UV365 irradiation than that under the UV254, and increased with the irradiation intensity. Continuous application of the external magnetic field at high strength remarkably improved the algal harvesting. Finally, the reuse of MNPs for multiple cycles of algal harvesting was studied, which aimed at increasing the sustainability and lowering the cost. PMID:25486124

  17. A diverse assemblage of indole-3-acetic acid producing bacteria associate with unicellular green algae.

    PubMed

    Bagwell, Christopher E; Piskorska, Magdalena; Soule, Tanya; Petelos, Angela; Yeager, Chris M

    2014-08-01

    Microalgae have tremendous potential as a renewable feedstock for the production of liquid transportation fuels. In natural waters, the importance of physical associations and biochemical interactions between microalgae and bacteria is generally well appreciated, but the significance of these interactions to algal biofuels production have not been investigated. Here, we provide a preliminary report on the frequency of co-occurrence between indole-3-acetic acid (IAA)-producing bacteria and green algae in natural and engineered ecosystems. Growth experiments with unicellular algae, Chlorella and Scenedesmus, revealed IAA concentration-dependent responses in chlorophyll content and dry weight. Importantly, discrete concentrations of IAA resulted in cell culture synchronization, suggesting that biochemical priming of cellular metabolism could vastly improve the reliability of high density cultivation. Bacterial interactions may have an important influence on algal growth and development; thus, the preservation or engineered construction of the algal-bacterial assembly could serve as a control point for achieving low input, reliable production of algal biofuels. PMID:24879600

  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. 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

  1. 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}.

  2. 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.

  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. Modelling the effect of exposing algae to pulses of S-metolachlor: How to include a delay to the onset of the effect and in the recovery.

    PubMed

    Copin, Pierre-Jean; Perronet, Léa; Chèvre, Nathalie

    2016-01-15

    In agriculture, herbicides are applied to improve crop productivity. During and after rain event, herbicides can be transported by surface runoff in streams and rivers. As a result, the exposure pattern in creeks is time-varying, i.e., a repeated pollution of aquatic system. In previous studies, we developed a model to assess the effects of pulse exposure patterns on algae. This model was validated for triazines and phenylureas, which are substances that induce effects directly after exposure with no delay in recovery. However, other herbicides display a mode of action characterized by a time-dependency effect and a delay in recovery. In this study, we therefore investigate whether this previous model could be used to assess the effects of pulse exposure by herbicides with time delay in effect and recovery. The current study focuses on the herbicide S-metolachlor. We showed that the effect of the herbicide begins only after 20 h of exposure for the alga Scenedesmus vacuolatus based on both the optical density and algal cells size measurements. Furthermore, the duration of delay of the recovery for algae previously exposed to S-metolachlor was 20 h and did not depend on the pulse exposure duration or the height of the peak concentration. By accounting for these specific effects, the measured and predicted effects were similar when pulse exposure of S-metolachlor is tested on the alga S. vacuolatus. However, the sensitivity of the alga is greatly modified after being previously exposed to a pulse of S-metolachlor. In the case of scenarios composed of several pulses, this sensitivity should be considered in the modelling. Therefore, modelling the effects of any pulse scenario of S-metolachlor on an alga is feasible but requires the determination of the effect trigger, the delay in recovery and the possible change in the sensitivity of the alga to the substance. PMID:26410701

  6. Toxicity of ammonia to algae in sewage oxidation ponds.

    PubMed Central

    Abeliovich, A; Azov, Y

    1976-01-01

    Ammonia, at concentrations over 2.0 mM and at pH values over 8.0, inhibits photosynthesis and growth of Scenedesmus obliquus, a dominant species in high-rate sewage oxidation ponds. Photosynthesis of Chlorella pyrenoidosa, Anacystis nidulans, and Plectonema boryanum is also susceptible to ammonia inhibition. Dark respiration and cell morphology were unaffected by any combination of pH and ammonia concentrations tested, thus limiting the apparent effect to inhibition of the normal function of the chloroplasts. Methylamine had the same effect as ammonia, and its penetration into the cells was found to be pH dependent. Therefore, the dependence of toxicity of amines to algae on pH apparently results from the inability to penetrate the cell membrane in the ionized form. When operated at 120-h detention time of raw wastewater, the high-rate oxidation pond maintained a steady state with respect to algal growth and oxygen concentration, and the concentration of ammonia did not exceed 1.0 mM. Shifting the pond to 48-h detention time caused an increase in ammonia concentration in the pond water to 2.5 mM, and the pond gradually turned anaerobic. Photosynthesis, which usually elevates the pH of the pond water to 9.0 to 10.0, could not proceed beyond pH 7.9 because of the high concentration of ammonia, and the algal population was washed out and reduced to a concentration that could maintain a doubling time of 48 h without photosynthesis bringing the pH to inhibitory levels. Under these conditions, the pH of the bond becomes a factor that limits the operational efficiency of the oxidation pond. PMID:7192

  7. 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

  8. 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.

  9. [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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  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. Enhancement of nutrient removal from swine wastewater digestate coupled to biogas purification by microalgae Scenedesmus spp.

    PubMed

    Prandini, Jean Michel; da Silva, Márcio Luís Busi; Mezzari, Melissa Paola; Pirolli, Mateus; Michelon, William; Soares, Hugo Moreira

    2016-02-01

    This work investigated the effects of swine wastewater-derived biogas on microalgae biomass production and nutrient removal rates from piggery wastewater concomitantly with biogas filtration. Photobioreactors with dominant Scenedesmus spp. were prepared using non-sterile digestate and exposed to different photoperiods. In the presence of biogas and autotrophic conditions microalgae yield of 1.1±0.2 g L(-1) (growth rate of 141.8±3.5 mg L(-1) d(-1)) was obtained leading to faster N-NH3 and P-PO4(3-) assimilation rate of 21.2±1.2 and 3.5±2.5 mg L(-1) d(-1), respectively. H2S up to 3000 ppmv was not inhibitory and completely removed. Maximum CO2 assimilation of 219±4.8 mg L(-1) d(-1) was achieved. Biological consumption of CH4 up to 18% v/v was verified. O2 up to 22% v/v was controlled by adding acetate to exacerbate oxygen demand by microorganisms. Microalgae-based wastewater treatment coupled to biogas purification accelerates nutrient removal concomitantly producing valuable biomass and biomethane. PMID:26700760

  16. Effect of food wastewater on biomass production by a green microalga Scenedesmus obliquus for bioenergy generation.

    PubMed

    Ji, Min-Kyu; Yun, Hyun-Shik; Park, Sanghyun; Lee, Hongkyun; Park, Young-Tae; Bae, Sunyoung; Ham, Jungyeob; Choi, Jaeyoung

    2015-03-01

    Effect of food wastewater (FW) on the biomass, lipid and carbohydrate production by a green microalga Scenedesmus obliquus cultivated in Bold's Basal Medium (BBM) was investigated. Different dilution ratios (0.5-10%) of BBM either with FW or salt solution (NaCl) or sea water (SW) were evaluated. S. obliquus showed the highest growth (0.41 g L(-1)), lipid productivity (13.3 mg L(-1) day L(-1)), carbohydrate productivity (14.7 mg L(-1) day L(-1)) and nutrient removal (38.9 mg TN L(-1) and 12.1 mg TP L(-1)) with 1% FW after 6 days of cultivation. The FW promoted algal autoflocculation due to formation of inorganic precipitates at an alkali pH. Fatty acid methyl ester analysis revealed that the palmitic and oleic acid contents were increased up to 8% with FW. Application of FW improved the growth, lipid/carbohydrate productivity and biomass recovery efficiency of S. obliquus, which can be exploited for cost effective production of microalgae biomass. PMID:25553643

  17. Isothermal and non-isothermal torrefaction characteristics and kinetics of microalga Scenedesmus obliquus CNW-N.

    PubMed

    Chen, Wei-Hsin; Wu, Zih-Ying; Chang, Jo-Shu

    2014-03-01

    Isothermal and non-isothermal torrefaction characteristics and kinetics of microalga Scenedesmus obliquus (S. obliquus) CNW-N are studied using thermogravimetric analysis. The pyrolysis of S. obliquus CNW-N with increasing temperature is characterized by four-stage decomposition. Depending on the torrefaction temperature, light, mild, and severe torrefaction from the weight loss and the maximum decomposition rate of the microalga can be classified. Under the same average temperature and torrefaction duration, non-isothermal torrefaction gives more severe pretreatment than the isothermal one. Increasing the heating rate of non-isothermal torrefaction also intensifies the pretreatment severity. Therefore, microalgae can be torrefied via non-isothermal torrefaction in a shorter time under the same pretreatment extent. The atomic H/C ratio in the microalga decreases with increasing torrefaction severity, whereas the atomic O/C ratio rises. The analysis suggests that the activation energy of isothermal torrefaction is 57.52×10(3)Jmol(-1), while it is between 40.14×10(3) and 88.41×10(3)Jmol(-1) for non-isothermal torrefaction. PMID:24457308

  18. Feasibility of using brewery wastewater for biodiesel production and nutrient removal by Scenedesmus dimorphus.

    PubMed

    Lutzu, Giovanni Antonio; Zhang, Wei; Liu, Tianzhong

    2016-01-01

    This work investigates the potential use of a brewery wastewater as a medium for the cultivation of the oleaginous species Scenedesmus dimorphus with the double aim of removing nutrients and to produce biomass as feedstock for biodiesel. For this purpose, effects of nitrogen (61.8-247 mg L(-1)), phosphorous (1.4-5.5 mg L(-1)), and iron (1.5-6 mg L(-1)) concentrations on growth, nutrients uptake, lipid accumulation, and fatty acids profile of this microalga were investigated. Results showed that brewery wastewater can be used as a culture medium even if nitrogen and phosphorous concentrations should have been modified to improve both biomass (6.82 g L(-1)) and lipid accumulation (44.26%). The analysis revealed a C16-C18 composition of 93.47% fatty acids methyl esters with a relative high portion of unsaturated ones (67.24%). High removal efficiency (>99%) for total nitrogen and total phosphorous and a reduction of up to 65% in chemical oxygen demand were achieved, respectively. The final microalgae biomass, considering its high lipid content as well as its compliance with the standards for the quality of biodiesel, and considering also the high removal efficiencies obtained for macronutrients and organic carbon, makes the brewery wastewater a viable option as a priceless medium for the cultivation of microalgae. PMID:26714635

  19. Optimization of aeration for biodiesel production by Scenedesmus obliquus grown in municipal wastewater.

    PubMed

    Han, Song-Fang; Jin, Wenbiao; Tu, Renjie; Abomohra, Abd El-Fatah; Wang, Zhi-Han

    2016-07-01

    Despite the significant breakthroughs in research on microalgae as a feedstock for biodiesel, its production cost is still much higher than that of fossil diesel. One possible solution to overcome this problem is to optimize algal growth and lipid production in wastewater. The present study examines the optimization of pretreatment of municipal wastewater and aeration conditions in order to enhance the lipid productivity of Scenedesmus obliquus. Results showed that no significant differences were recorded in lipid productivity of S. obliquus grown in primary settled or sterilized municipal wastewater; however, ultrasound pretreatment of wastewater significantly decreased the lipid production. Whereas, aeration rates of 0.2 vvm significantly increased lipid content by 51 %, with respect to the non-aerated culture, which resulted in maximum lipid productivity (32.5 mg L(-1) day(-1)). Furthermore, aeration enrichment by 2 % CO2 resulted in increase of lipid productivity by 46 % over the CO2 non-enriched aerated culture. Fatty acid profile showed that optimized aeration significantly enhanced monounsaturated fatty acid production, composed mainly of C18:1, by 1.8 times over the non-aerated S. obliquus culture with insignificant changes in polyunsaturated fatty acid proportion; suggesting better biodiesel characteristics for the optimized culture. PMID:26969589

  20. Photobiotreatment: influence of nitrogen and phosphorus ratio in wastewater on growth kinetics of Scenedesmus obliquus.

    PubMed

    Arbib, Z; Ruiz, J; Alvarez-Díaz, Pablo; Garrido-Pérez, C; Barragan, J; Perales, J A

    2013-01-01

    Nitrogen and phosphorus concentration in the effluent of a wastewater treatment plant can vary significantly, which could affect the growth kinetic and chemical composition of microalgae when cultivated in this medium. The aim of this work was to study the rate of growth, nutrient removal and carbon dioxide biofixation as well as biomass composition of Scenedesmus obliquus (S. obliquus) when it is cultivated in wastewater at different nitrogen and phosphorus ratio, from 1:1 to 35:1. A more homogeneous method for calculating productivities in batch reactors was proposed. The proper N:P ratio for achieving optimum batch biomass productivity ranged between 9 and 13 (263 and 322 mg L(-1) d(-1) respectively). This was also the ratio range for achieving a total N and P removal. Above and below this range (9-13) the maximum biomass concentration changed, instead of the specific growth rate.The maximum carbon dioxide biofixation rate was achieved at N:P ratio between 13 and 22 (553 and 557 mg CO2 L(-1) d(-1) respectively). Lipid and crude protein content, both depend on the aging culture, reaching the maximum lipid content (34%) at the lowest N:P (1:1) and the maximum crude protein content (34.2%) at the highest N:P (35:1). PMID:23819274

  1. Maximizing the production of Scenedesmus obliquus in photobioreactors under different irradiation regimes: experiments and modeling.

    PubMed

    Barbera, Elena; Sforza, Eleonora; Bertucco, Alberto

    2015-11-01

    Maximizing biomass productivity and photosynthetic efficiency are key factors to develop large-scale microalgae cultivation for biodiesel production. If the photobioreactor (PBR) is not operated under proper conditions, productivity and efficiency values drop considerably. In this work, the growth of Scenedesmus obliquus in continuous flat-panel PBR is considered. Experimental data and simulations were used with the aim of determining suitable working conditions to achieve maximum productivity. Microalgae concentration and productivity have been measured in a continuous 250 mL flat-panel PBR as a function of the space-time τ. Simulations were performed at both low and high irradiance values, with different light regimes (constant light and day-night profiles). Model parameters were optimized based on laboratory-scale experimental data, and the importance of the maintenance energy requirement as a function of light intensity was outlined. The effect of different extent of axial mixing on PBR performances was investigated. Results obtained show how to determine optimum working conditions and how they could be used in the design of a large-scale PBR to achieve maximum microalgal productivity. PMID:26288951

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. Probing the elastic response of microalga Scenedesmus dimorphus in dry and aqueous environments through atomic force microscopy

    SciTech Connect

    Warren, K. M.; Mpagazehe, J. N.; Higgs, C. F. E-mail: higgs@andrew.cmu.edu; LeDuc, P. R. E-mail: higgs@andrew.cmu.edu

    2014-10-20

    With the re-emergence of microalgae as a replacement feedstock for petroleum-derived oils, researchers are working to understand its chemical and mechanical behavior. In this work, the mechanical properties of microalgae, Scenedesmus dimorphus, were investigated at the subcellular level to determine the elastic response of cells that were in an aqueous and dried state using nano-scale indentation through atomic force microscopy. The elastic modulus of single-celled S. dimorphus cells increased over tenfold from an aqueous state to a dried state, which allows us to better understand the biophysical response of microalgae to stress.

  7. Probing the elastic response of microalga Scenedesmus dimorphus in dry and aqueous environments through atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Warren, K. M.; Mpagazehe, J. N.; LeDuc, P. R.; Higgs, C. F.

    2014-10-01

    With the re-emergence of microalgae as a replacement feedstock for petroleum-derived oils, researchers are working to understand its chemical and mechanical behavior. In this work, the mechanical properties of microalgae, Scenedesmus dimorphus, were investigated at the subcellular level to determine the elastic response of cells that were in an aqueous and dried state using nano-scale indentation through atomic force microscopy. The elastic modulus of single-celled S. dimorphus cells increased over tenfold from an aqueous state to a dried state, which allows us to better understand the biophysical response of microalgae to stress.

  8. 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.

  9. The effect of discontinuous airlift mixing in outdoor flat panel photobioreactors on growth of Scenedesmus obliquus.

    PubMed

    Leupold, Marco; Hindersin, Stefan; Kerner, Martin; Hanelt, Dieter

    2013-11-01

    Discontinuous airlift mixing was realized by injecting pressured air at time intervals with a frequency between 0.033 and 0.25 Hz (at 80 kPa; i.e., every 4-30 s; valve opening time 800 ms) into outdoor flat panel photobioreactors ([Formula: see text]). This caused a flow velocity between 2 and 20 cm s(-1) of the culture medium within the photobioreactor and the mixing time was between 38 and 103.5 s, requiring 0.175-1.340 L(gas volume) L(photobioreactor volume)(-1) min(-1) pressured air. In order to detect the effect on growth of Scenedesmus obliquus during outdoor experiments and to be able to compare obtained results, a batch run with an airlift frequency of 0.25 Hz was simultaneously used as control. Growth at different airlift frequencies was measured by the increase of cell dry weight (CDW) during 3-5 days and biomass yield on light energy was calculated. With increasing airlift frequencies, growth increased from 52 to 91 % compared to the control. When CDW was at around 1.0-1.5 g L(-1), airlift frequency had no effect on growth, indicating that mass transfer gradients of nutrients and gas were not the limiting factors of growth. Above 1.5 g CDW L(-1), growth increased with increasing airlift frequency and light limitation for a single cell occurred. This effect was observed during low and high irradiance and it is concluded that a higher mean flow causes a better light distribution, resulting in an enhanced growth. Biomass productivity and demand of pressured air are correlated logarithmically, which enables to save mixing energy during cultivation. PMID:23494400

  10. Kinetics of the oxyhydrogen reaction in the presence and absence of carbon dioxide in Scenedesmus obliquus

    SciTech Connect

    Erbes, D.L.; Gibbs, M.

    1981-01-01

    The oxyhydrogen reaction in the presence and absence of CO/sub 2/ was studied in H/sub 2/-adapted Scenedesmus obliquus by monitoring the initial rates of H/sub 2/, O/sub 2/, and /sup 14/CO/sub 2/ uptake and the effect of inhibitors on these rates with gas-sensing electrodes and isotopic techniques. In the presence of 0.02 atmosphere O/sub 2/, the pH/sub 2/ was varied from 0 to 1 atmosphere. Whereas the rate of O/sub 2/ uptake increased by only 30%, the rate of H/sub 2/ uptake increased severalfold over the range of pH/sub 2/ values. At 0.1 atmosphere H/sub 2/ and 0.02 atmosphere O/sub 2/, rates for H/sub 2/ and O/sub 2/ uptake were between 15 and 25 micromoles per milligram chlorophyll per hour. As the pH/sub 2/ was changed from 0 to 1 atmosphere, the quotient H/sub 2/:O/sub 2/ changed from 0 to roughly 2. This change may reflect the competition between H/sub 2/ and the endogenous respiratory electron donors. Respiration in the presence of glucose and acetate was also competitive with H/sub 2/ uptake. KCN inhibited equally respiration (O/sub 2/ uptake in the absence of H/sub 2/) and the oxyhydrogen reaction in the presence and absence of CO/sub 2/. The uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone accelerated the rate of respiration and the oxyhydrogen reaction to a similar extent. It was concluded that the oxyhydrogen reaction both in the presence and absence of CO/sub 2/ has properties in common with components of respiration and photosynthesis. Participation of these two processes in the oxyhydrogen reaction would require a closely linked shuttle between mitochondrion and chloroplast.

  11. Microscopic Gardens: A Close Look at Algae.

    ERIC Educational Resources Information Center

    Foote, Mary Ann

    1983-01-01

    Describes classroom activities using algae, including demonstration of eutrophication, examination of mating strains, and activities with Euglena. Includes on algal morphology/physiology, types of algae, and field sources for collecting these organisms. (JN)

  12. 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

  13. Formation of algae growth constitutive relations for improved algae modeling.

    SciTech Connect

    Gharagozloo, Patricia E.; Drewry, Jessica L.

    2013-01-01

    This SAND report summarizes research conducted as a part of a two year Laboratory Directed Research and Development (LDRD) project to improve our abilities to model algal cultivation. Algae-based biofuels have generated much excitement due to their potentially large oil yield from relatively small land use and without interfering with the food or water supply. Algae mitigate atmospheric CO2 through metabolism. Efficient production of algal biofuels could reduce dependence on foreign oil by providing a domestic renewable energy source. Important factors controlling algal productivity include temperature, nutrient concentrations, salinity, pH, and the light-to-biomass conversion rate. Computational models allow for inexpensive predictions of algae growth kinetics in these non-ideal conditions for various bioreactor sizes and geometries without the need for multiple expensive measurement setups. However, these models need to be calibrated for each algal strain. In this work, we conduct a parametric study of key marine algae strains and apply the findings to a computational model.

  14. The effect of low temperature on Antarctic endolithic green algae

    NASA Technical Reports Server (NTRS)

    Meyer, M. A.; Morris, G. J.; Friedmann, E. I.

    1988-01-01

    Laboratory experiments show that undercooling to about -5 degrees C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5 degrees C and -5 degrees C or -10 degrees C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid cooling to -50 degrees C. 14CO2 incorporation after freezing to -20 degrees C was unaffected in H. antarctica or in Trebouxia sp. but slightly depressed in Stichococcus sp. (isolated from a less extreme Antarctic habitat). These results suggest that the freezing regime in the Antarctic desert is not injurious to endolithic algae. It is likely that the freezing-point depression inside the rock makes available liquid water for metabolic activity at subzero temperatures. Freezing may occur more frequently on the rock surface and contribute to the abiotic nature of the surface.

  15. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  16. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1121 Red algae. (a) Red algae are seaweeds of the species Gloiopeltis furcata, Porphyra...

  17. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1120 Brown algae. (a) Brown algae are seaweeds of the species Analipus japonicus, Eisenia...

  18. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  19. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  20. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  1. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  2. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  3. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  4. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  5. Effect of indigo dye effluent on the growth, biomass production and phenotypic plasticity of Scenedesmus quadricauda (Chlorococcales).

    PubMed

    Chia, Mathias A; Musa, Rilwan I

    2014-03-01

    The effect of indigo dye effluent on the freshwater microalga Scenedesmus quadricauda ABU12 was investigated under controlled laboratory conditions. The microalga was exposed to different concentrations of the effluent obtained by diluting the dye effluent from 100 to 175 times in bold basal medium (BBM). The growth rate of the microalga decreased as indigo dye effluent concentration increased (p <0.05). The EC50 was found to be 166 dilution factor of the effluent. Chlorophyll a, cell density and dry weight production as biomarkers were negatively affected by high indigo dye effluent concentration, their levels were higher at low effluent concentrations (p <0.05). Changes in coenobia size significantly correlated with the dye effluent concentration. A shift from large to small coenobia with increasing indigo dye effluent concentration was obtained. We conclude that even at low concentrations; effluents from textile industrial processes that use indigo dye are capable of significantly reducing the growth and biomass production, in addition to altering the morphological characteristics of the freshwater microalga S. quadricauda. The systematic reduction in the number of cells per coenobium observed in this study further confirms that environmental stress affects coenobium structure in the genus Scenedesmus, which means it can be considered an important biomarker for toxicity testing. PMID:24676177

  6. Algae. LC Science Tracer Bullet.

    ERIC Educational Resources Information Center

    Niskern, Diana, Comp.

    The plants and plantlike organisms informally grouped together as algae show great diversity of form and size and occur in a wide variety of habitats. These extremely important photosynthesizers are also economically significant. For example, some species contaminate water supplies; others provide food for aquatic animals and for man; still others…

  7. Biological importance of marine algae

    PubMed Central

    El Gamal, Ali A.

    2009-01-01

    Marine organisms are potentially prolific sources of highly bioactive secondary metabolites that might represent useful leads in the development of new pharmaceutical agents. Algae can be classified into two main groups; first one is the microalgae, which includes blue green algae, dinoflagellates, bacillariophyta (diatoms)… etc., and second one is macroalgae (seaweeds) which includes green, brown and red algae. The microalgae phyla have been recognized to provide chemical and pharmacological novelty and diversity. Moreover, microalgae are considered as the actual producers of some highly bioactive compounds found in marine resources. Red algae are considered as the most important source of many biologically active metabolites in comparison to other algal classes. Seaweeds are used for great number of application by man. The principal use of seaweeds as a source of human food and as a source of gums (phycocollides). Phycocolloides like agar agar, alginic acid and carrageenan are primarily constituents of brown and red algal cell walls and are widely used in industry. PMID:23960716

  8. Determining surface areas of marine alga cells by acid-base titration method.

    PubMed

    Wang, X; Ma, Y; Su, Y

    1997-09-01

    A new method for determining the surface area of living marine alga cells was described. The method uses acid-base titration to measure the surface acid/base amount on the surface of alga cells and uses the BET (Brunauer, Emmett, and Teller) equation to estimate the maximum surface acid/base amount, assuming that hydrous cell walls have carbohydrates or other structural compounds which can behave like surface Brönsted acid-base sites due to coordination of environmental H2O molecules. The method was applied to 18 diverse alga species (including 7 diatoms, 2 flagellates, 8 green algae and 1 red alga) maintained in seawater cultures. For the species examined, the surface areas of individual cells ranged from 2.8 x 10(-8) m2 for Nannochloropsis oculata to 690 x 10(-8) m2 for Dunaliella viridis, specific surface areas from 1,030 m2.g-1 for Dunaliella salina to 28,900 m2.g-1 for Pyramidomonas sp. Measurement accuracy was 15.2%. Preliminary studies show that the method may be more promising and accurate than light/electron microscopic measurements for coarse estimation of the surface area of living algae. PMID:9297794

  9. The biological soil crusts of the San Nicolas Island: Enigmatic algae from a geographically isolated ecosystem

    USGS Publications Warehouse

    Flechtner, V.R.; Johansen, J.R.; Belnap, J.

    2008-01-01

    Composite soil samples from 7 sites on San Nicolas Island were evaluated quantitatively and qualitatively for the presence of cyanobacteria and eukaryotic microalgae. Combined data demonstrated a rich algal flora with 19 cyanobacterial and 19 eukaryotic microalgal genera being identified, for a total of 56 species. Nine new species were identified and described among the cyanobacteria and the eukaryotic microalgae that were isolated: Leibleinia edaphica, Aphanothece maritima, Chroococcidiopsis edaphica, Cyanosarcina atroveneta, Hassallia californica, Hassallia pseudoramosissima, Microchaete terrestre, Palmellopsis californiens, and Pseudotetracystis compactis. Distinct distributional patterns of algal taxa existed among sites on the island and among soil algal floras of western North America. Some algal taxa appeared to be widely distributed across many desert regions, including Microcoleus vaginatus, Nostoc punctiforme, Nostoc paludosum, and Tolypothrix distorta, Chlorella vulgaris, Diplosphaera cf. chodatii, Myrmecia astigmatica, Myrmecia biatorellae, Hantzschia amphioxys, and Luticola mutica. Some taxa share a distinctly southern distribution with soil algae from southern Arizona, southern California, and Baja California (e.g., Scenedesmus deserticola and Eustigmatos magnus). The data presented herein support the view that the cyanobacterial and microalgal floras of soil crusts possess significant biodiversity, much of it previously undescribed.

  10. Distribution of periphytic algae in wetlands (Palm swamps, Cerrado), Brazil.

    PubMed

    Dunck, B; Nogueira, I S; Felisberto, S A

    2013-05-01

    The distribution of periphytic algae communities depends on various factors such as type of substrate, level of disturbance, nutrient availability and light. According to the prediction that impacts of anthropogenic activity provide changes in environmental characteristics, making impacted Palm swamps related to environmental changes such as deforestation and higher loads of nutrients via allochthonous, the hypothesis tested was: impacted Palm swamps have higher richness, density, biomass and biovolume of epiphytic algae. We evaluated the distribution and structure of epiphytic algae communities in 23 Palm swamps of Goiás State under different environmental impacts. The community structure attributes here analyzed were composition, richness, density, biomass and biovolume. This study revealed the importance of the environment on the distribution and structuration of algal communities, relating the higher values of richness, biomass and biovolume with impacted environments. Acidic waters and high concentration of silica were important factors in this study. Altogether 200 taxa were identified, and the zygnemaphycea was the group most representative in richness and biovolume, whereas the diatoms, in density of studied epiphyton. Impacted Palm swamps in agricultural area presented two indicator species, Gomphonema lagenula Kützing and Oedogonium sp, both related to mesotrophic to eutrophic conditions for total nitrogen concentrations of these environments. PMID:23917560

  11. Measurements of photorespiration in some microscopic algae.

    PubMed

    Cheng, K H; Colman, B

    1974-09-01

    The rate of photorespiration in three green algae and four blue-green algae was determined by the measurement of the rate of loss of photosynthetically fixed (14)CO2 in light in CO2-free air at 25°. In all algae studied, CO2 evolution in light was considerably less than that in the dark, except for Chlamydomonas reinhardii which released slightly more CO2 in the light. Raising the temperature to 35° had little effect on the ratio of light to dark (14)CO2 release. Blue-green algae showed the lowest photorespiration rate of the algae studied. PMID:24458883

  12. Distinctive origins of group I introns found in the COXI genes of three gree algae.

    PubMed

    Watanabe, K I; Ehara, M; Inagaki, Y; Ohama, T

    1998-06-15

    Upon surveying the cytochrome c oxidase subunit I (COXI) gene of green algae, we found group I introns in three species of algae, Chlorella vulgaris (Cv), Scenedesmus quadricauda (Sq) and Protosiphon botryoides (Pb). The comparative analysis of these nucleotide sequences and their secondary structures revealed that the introns of Cv, Sq, and Pb belong to groups IB1, ID, and IB2, respectively. Each of the three introns contained an open reading frame (ORF) that showed a similarity to the sequence of the LAGLIDADG endonuclease family. However, each of the intronic ORFs in Sq and Pb had a discontinuity in the middle of' the sequences coding for the LAGLIDADG endonuclease. Either of the two ORFs could be restored to a sequence homologous to the LAGLIDADG endonuclease by the insertion of a nucleotide in the appropriate position. In Sq, a putative pseudo-knot structure was detected in the intronic ORF This suggests the occurrence of a ribosomal frameshift in the translation of the ORF. because such pseudo-knot structures are common in viral ORFs employing a (-1) ribosomal frameshift. In the phylogenetic tree that was inferred from the amino acid sequences of algal and non-algal intronic ORFs, the three algal ORFs did not make a cluster, but were scattered throughout the tree. In addition. each of the three algal ORFs showed a close relationship to the ORFs of non-algal introns that were inserted at the corresponding site of the COX] gene, suggesting distinctive origins of the three algal introns via independent horizontal transfers. PMID:9714606

  13. 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

  14. Enantioselective toxicities of chiral ionic liquids 1-alkyl-3-methylimidazolium lactate to aquatic algae.

    PubMed

    Chen, Hui; Zou, Yuqin; Zhang, Lijuan; Wen, Yuezhong; Liu, Weiping

    2014-09-01

    With the wide application of chiral ionic liquids (CILs) as green solvents, their threats to the aquatic environment cannot be ignored. Thus, risk assessment and the prospective design of inherently safe CILs have become more urgent. However, whether enantioselectivity is a feature of the aquatic toxicity of CILs is poorly understood. Herein, we describe the first investigation into the ecotoxicities of CILs toward green algae Scenedesmus obliquus and Euglena gracilis. A series of methylimidazolium lactic ionic liquids, which cation parts with different alkyl chains and anion part is enantiomers of lactate, are used as representative CILs. The results of S. obliquus showed that the EC50 value of L-(+)-1-ethyl-3-methylimidazolium lactate (L-(+)-EMIM L) was more than 5000 μM, while the EC50 value of D-(-)-1-ethyl-3-methylimidazolium lactate (D-(-)-EMIM L) was 2255.21 μM. Such a distinct difference indicates the enantioselective toxicity of CILs to algae. This enantioselectivity initially persisted with increasing carbon chain length, but no longer exhibited when with greater carbon chain lengths, due to changes in the toxicity weightings of the cation parts. Further research showed that the enantioselective effects of CILs resulted from the differences in the production of reactive oxygen species, the damage to cell membrane integrity and cell wall after exposure to CILs. Results from this study showed that monitoring for the racemate CILs will give an inadequate or misleading environmental risk assessment. Thus, we should improve our ability to predict their effects in natural environments. In the meantime, non-selective use of CILs will do harm to aquatic organisms. Therefore, to minimize their potential for environmental impact, the enantioselective toxicities of CILs with short alkyl chains should be taken into consideration. PMID:24880783

  15. [Effects of mercury concentration on life table demography of Moina macrocopa under different Scenedesmus obliquus densities].

    PubMed

    Huang, Ya; Wang, Ling; Mu, Wei-ping; Ren, Tong-tong; Pan, Ling; Xi, Yi-long

    2015-12-01

    In order to compare the chronic toxicity of pollutants to organisms in an aquatic environment under different food densities, the cladoceran Moina macrocopa was used as test animal to investigate the effects of Hg²⁺ concentrations (0, 0.4, 1.1, 1.8, 2.5, 3.2 and 3.9 µg · L⁻¹) on its life table demography under low (0.5 x 10⁶ cells · mL⁻¹), medium (1.0 x 10⁶ cells · mL⁻¹) and high (2.0 x 10⁶ cells · mL⁻¹) densities of Scenedesmus obliquus. The results showed that at low and high food levels, certain concentrations of Hg²⁺ had inhibitory effects on survival, reproduction and population growth of M. macrocopa. However, at the medium food level, the inhibitory effects disappeared. Compared with the control, at the low food level, Hg²⁺ at 0.4-2.5 and 3.9 µg · L⁻¹ significantly decreased the life expectancy at hatching, Hg²⁺ at 0.4, 1.1, 2.5 and 3.9 µg · L⁻¹ decreased the generation time, Hg²⁺ at 1.1, 2.5 and 3.9 µg · L⁻¹ decreased the net reproduction rate, and Hg²⁺ at 3.9 µg · L⁻¹ decreased the gross reproduction rate of M. macrocopa. At the high food level, Hg²⁺ at 1.1 µg · L⁻¹ decreased the intrinsic rate of population increase, and Hg²⁺ at 3.9 µg · L⁻¹ decreased the life expectancy at hatching and the net reproduction rate of M. macrocopa. However, at the medium food level, Hg²⁺ at 3.2 µg · L⁻¹ increased the life expectancy at hatching of M. macrocopa. When S. obliquus density was 0.5 x 10⁶ cells · mL⁻¹, there were significant dose-effect relationships between Hg²⁺ concentration and the life expectancy at hatching, the generation time as well as the cross reproduction rate of M. macrocopa. However, when S. obliquus density was 1.0 x 10⁶ or 2.0 x 10⁶ cells · mL⁻¹, there were no any significant dose-effect relationships between Hg²⁺ concentration and each of the life table demographic parameters of M. macrocopa. PMID:27112029

  16. “Rational” Management of Dichlorophenols Biodegradation by the Microalga Scenedesmus obliquus

    PubMed Central

    Papazi, Aikaterini; Kotzabasis, Kiriakos

    2013-01-01

    The microalga Scenedesmus obliquus exhibited the ability to biodegrade dichlorophenols (dcps) under specific autotrophic and mixotrophic conditions. According to their biodegradability, the dichlorophenols used can be separated into three distinct groups. Group I (2,4-dcp and 2,6 dcp – no meta-substitution) consisted of quite easily degraded dichlorophenols, since both chloride substituents are in less energetically demanding positions. Group II (2,3-dcp, 2,5-dcp and 3,4-dcp – one meta-chloride) was less susceptible to biodegradation, since one of the two substituents, the meta one, required higher energy for C-Cl-bond cleavage. Group III (3,5-dcp – two meta-chlorides) could not be biodegraded, since both chlorides possessed the most energy demanding positions. In general, when the dcp-toxicity exceeded a certain threshold, the microalga increased the energy offered for biodegradation and decreased the energy invested for biomass production. As a result, the biodegradation per cell volume of group II (higher toxicity) was higher, than group I (lower toxicity) and the biodegradation of dichlorophenols (higher toxicity) was higher than the corresponding monochlorophenols (lower toxicity). The participation of the photosynthetic apparatus and the respiratory mechanism of microalga to biodegrade the group I and the group II, highlighted different bioenergetic strategies for optimal management of the balance between dcp-toxicity, dcp-biodegradability and culture growth. Additionally, we took into consideration the possibility that the intermediates of each dcp-biodegradation pathway could influence differently the whole biodegradation procedures. For this reason, we tested all possible combinations of phenolic intermediates to check cometabolic interactions. The present contribution bring out the possibility of microalgae to operate as “smart” bioenergetic “machines”, that have the ability to continuously “calculate” the energy reserves and

  17. Iron encrustations on filamentous algae colonized by Gallionella-related bacteria in a metal-polluted freshwater stream

    NASA Astrophysics Data System (ADS)

    Mori, J. F.; Neu, T. R.; Lu, S.; Händel, M.; Totsche, K. U.; Küsel, K.

    2015-09-01

    some putative predators of algae. A loss of chloroplasts in the brown algae could have led to lower photosynthetic activities and reduced EPS production, which is known to affect predator colonization. Collectively, our results suggest the coexistence of oxygen-generating algae Tribonema sp. and strictly microaerophilic neutrophilic FeOB in a heavy metal-rich environment.

  18. The remote sensing of algae

    NASA Technical Reports Server (NTRS)

    Thorne, J. F.

    1977-01-01

    State agencies need rapid, synoptic and inexpensive methods for lake assessment to comply with the 1972 Amendments to the Federal Water Pollution Control Act. Low altitude aerial photography may be useful in providing information on algal type and quantity. Photography must be calibrated properly to remove sources of error including airlight, surface reflectance and scene-to-scene illumination differences. A 550-nm narrow wavelength band black and white photographic exposure provided a better correlation to algal biomass than either red or infrared photographic exposure. Of all the biomass parameters tested, depth-integrated chlorophyll a concentration correlated best to remote sensing data. Laboratory-measured reflectance of selected algae indicate that different taxonomic classes of algae may be discriminated on the basis of their reflectance spectra.

  19. [Discrimination of Red Tide algae by fluorescence spectra and principle component analysis].

    PubMed

    Su, Rong-guo; Hu, Xu-peng; Zhang, Chuan-song; Wang, Xiu-lin

    2007-07-01

    Fluorescence discrimination technology for 11 species of the Red Tide algae at genus level was constructed by principle component analysis and non-negative least squares. Rayleigh and Raman scattering peaks of 3D fluorescence spectra were eliminated by Delaunay triangulation method. According to the results of Fisher linear discrimination, the first principle component score and the second component score of 3D fluorescence spectra were chosen as discriminant feature and the feature base was established. The 11 algae species were tested, and more than 85% samples were accurately determinated, especially for Prorocentrum donghaiense, Skeletonema costatum, Gymnodinium sp., which have frequently brought Red tide in the East China Sea. More than 95% samples were right discriminated. The results showed that the genus discriminant feature of 3D fluorescence spectra of Red Tide algae given by principle component analysis could work well. PMID:17891964

  20. Synthetic polyester from algae oil.

    PubMed

    Roesle, Philipp; Stempfle, Florian; Hess, Sandra K; Zimmerer, Julia; Río Bártulos, Carolina; Lepetit, Bernard; Eckert, Angelika; Kroth, Peter G; Mecking, Stefan

    2014-06-23

    Current efforts to technically use microalgae focus on the generation of fuels with a molecular structure identical to crude oil based products. Here we suggest a different approach for the utilization of algae by translating the unique molecular structures of algae oil fatty acids into higher value chemical intermediates and materials. A crude extract from a microalga, the diatom Phaeodactylum tricornutum, was obtained as a multicomponent mixture containing amongst others unsaturated fatty acid (16:1, 18:1, and 20:5) phosphocholine triglycerides. Exposure of this crude algae oil to CO and methanol with the known catalyst precursor [{1,2-(tBu2 PCH2)2C6H4}Pd(OTf)](OTf) resulted in isomerization/methoxycarbonylation of the unsaturated fatty acids into a mixture of linear 1,17- and 1,19-diesters in high purity (>99 %). Polycondensation with a mixture of the corresponding diols yielded a novel mixed polyester-17/19.17/19 with an advantageously high melting and crystallization temperature. PMID:24845347

  1. Parasites in algae mass culture

    PubMed Central

    Carney, Laura T.; Lane, Todd W.

    2014-01-01

    Parasites are now known to be ubiquitous across biological systems and can play an important role in modulating algal populations. However, there is a lack of extensive information on their role in artificial ecosystems such as algal production ponds and photobioreactors. Parasites have been implicated in the demise of algal blooms. Because individual mass culture systems often tend to be unialgal and a select few algal species are in wide scale application, there is an increased potential for parasites to have a devastating effect on commercial scale monoculture. As commercial algal production continues to expand with a widening variety of applications, including biofuel, food and pharmaceuticals, the parasites associated with algae will become of greater interest and potential economic impact. A number of important algal parasites have been identified in algal mass culture systems in the last few years and this number is sure to grow as the number of commercial algae ventures increases. Here, we review the research that has identified and characterized parasites infecting mass cultivated algae, the techniques being proposed and or developed to control them, and the potential impact of parasites on the future of the algal biomass industry. PMID:24936200

  2. Effects of nitrogen source availability and bioreactor operating strategies on lutein production with Scenedesmus obliquus FSP-3.

    PubMed

    Ho, Shih-Hsin; Xie, Youping; Chan, Ming-Chang; Liu, Chen-Chun; Chen, Chun-Yen; Lee, Duu-Jong; Huang, Chieh-Chen; Chang, Jo-Shu

    2015-05-01

    In this study, the effects of the type and concentration of nitrogen sources on the cell growth and lutein content of an isolated microalga Scenedesmus obliquus FSP-3 were investigated. With batch culture, the highest lutein content (4.61 mg/g) and lutein productivity (4.35 mg/L/day) were obtained when using 8.0 mM calcium nitrate as the nitrogen source. With this best nitrogen source condition, the microalgae cultivation was performed using two bioreactor strategies (namely, semi-continuous and two-stage operations) to further enhance the lutein content and productivity. Using semi-continuous operation with a 10% medium replacement ratio could obtain the highest biomass productivity (1304.8 mg/L/day) and lutein productivity (6.01 mg/L/day). This performance is better than most related studies. PMID:25453431

  3. Scenedesmus incrassatulus CLHE-Si01: a potential source of renewable lipid for high quality biodiesel production.

    PubMed

    Arias-Peñaranda, Martha T; Cristiani-Urbina, Eliseo; Montes-Horcasitas, Carmen; Esparza-García, Fernando; Torzillo, Giuseppe; Cañizares-Villanueva, Rosa Olivia

    2013-07-01

    The potential of microalgal oil from Scenedesmus incrassatulus as a feedstock for biodiesel production was studied. Cell concentration of S. incrassatulus and lipid content obtained during mixotrophic growth were 1.8 g/L and 19.5 ± 1.5% dry cell weight, respectively. The major components of biodiesel obtained from S. incrassatulus oil were methyl palmitate (26%) and methyl linoleate (49%), which provided a strong indication of high quality biodiesel. Fuel properties were determined by empirical equations and found to be within the limits of biodiesel standard ASTM D6751 and EN 14214. The quality properties of the biodiesel were high cetane number (62), low density (803 kg/m(3)), low viscosity (3.78 mm(2)/s), oxidation stability (9h) and cold filter plugging point (-4°C). Hence, S. incrassatulus has potential as a feedstock for the production of excellent quality biodiesel. PMID:23688667

  4. Nitrogen removal and recycling by Scenedesmus obliquus in semicontinuous cultures using artificial wastewater and a simulated light and temperature cycle.

    PubMed

    Voltolina, Domenico; Gómez-Villa, Herlinda; Correa, Gabriel

    2005-02-01

    Semicontinuous cultures of Scenedesmus obliquus in artificial wastewater were maintained with 30% and 40% daily dilutions and under a 14:10 h light-dark cycle, with temperatures of 25.5 and 17 degrees C during light and dark hours. Under this regime, the production of organic biomass was 39.3 and 25.2 mg l(-1)d(-1) for the 30% and 40% dilutions, and 24.9 and 16.7 mg l(-1)d(-1) of single-cell proteins. Most of the nitrogen removal took place during the light hours, with daily totals of 9.27 and 8.45 mg l(-1) for the 30% and 40% dilutions. With the former, 43.7% of the nitrogen removed was recycled by the microalgae into proteins and other organic nitrogen cell contents, but this efficiency decreased to 26.4% when the dilutions were raised to 40%. PMID:15474938

  5. Red algae and their use in papermaking.

    PubMed

    Seo, Yung-Bum; Lee, Youn-Woo; Lee, Chun-Han; You, Hack-Chul

    2010-04-01

    Gelidialian red algae, that contain rhizoidal filaments, except the family Gelidiellaceae were processed to make bleached pulps, which can be used as raw materials for papermaking. Red algae consist of rhizoidal filaments, cortical cells usually reddish in color, and medullary cells filled with mucilaginous carbohydrates. Red algae pulp consists of mostly rhizoidal filaments. Red algae pulp of high brightness can be produced by extracting mucilaginous carbohydrates after heating the algae in an aqueous medium and subsequently treating the extracted with bleaching chemicals. In this study, we prepared paper samples from bleached pulps obtained from two red algae species (Gelidium amansii and Gelidium corneum) and compared their properties to those of bleached wood chemical pulps. PMID:20022488

  6. Stochastic Forecasting of Algae Blooms in Lakes

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.

    2013-01-15

    We consider the development of harmful algae blooms (HABs) in a lake with uncertain nutrients inflow. Two general frameworks, Fokker-Planck equation and the PDF methods, are developed to quantify the resultant concentration uncertainty of various algae groups, via deriving a deterministic equation of their joint probability density function (PDF). A computational example is examined to study the evolution of cyanobacteria (the blue-green algae) and the impacts of initial concentration and inflow-outflow ratio.

  7. A new microscopic method to analyse desiccation-induced volume changes in aeroterrestrial green algae.

    PubMed

    Lajos, K; Mayr, S; Buchner, O; Blaas, K; Holzinger, A

    2016-08-01

    Aeroterrestrial green algae are exposed to desiccation in their natural habitat, but their actual volume changes have not been investigated. Here, we measure the relative volume reduction (RVRED ) in Klebsormidium crenulatum and Zygnema sp. under different preset relative air humidities (RH). A new chamber allows monitoring RH during light microscopic observation of the desiccation process. The RHs were set in the range of ∼4 % to ∼95% in 10 steps. RVRED caused by the desiccation process was determined after full acclimation to the respective RHs. In K. crenulatum, RVRED (mean ± SE) was 46.4 ± 1.9%, in Zygnema sp. RVRED was only 34.3 ± 2.4% at the highest RH (∼95%) tested. This indicates a more pronounced water loss at higher RHs in K. crenulatum versus Zygnema sp. By contrast, at the lowest RH (∼4%) tested, RVRED ranged from 75.9 ± 2.7% in K. crenulatum to 83.9 ± 2.2% in Zygnema sp. The final volume reduction is therefore more drastic in Zygnema sp. These data contribute to our understanding of the desiccation process in streptophytic green algae, which are considered the closest ancestors of land plants. PMID:27075881

  8. A new microscopic method to analyse desiccation‐induced volume changes in aeroterrestrial green algae

    PubMed Central

    LAJOS, K.; MAYR, S.; BUCHNER, O.; BLAAS, K.

    2016-01-01

    Summary Aeroterrestrial green algae are exposed to desiccation in their natural habitat, but their actual volume changes have not been investigated. Here, we measure the relative volume reduction (RVRED) in Klebsormidium crenulatum and Zygnema sp. under different preset relative air humidities (RH). A new chamber allows monitoring RH during light microscopic observation of the desiccation process. The RHs were set in the range of ∼4 % to ∼95% in 10 steps. RVRED caused by the desiccation process was determined after full acclimation to the respective RHs. In K. crenulatum, RVRED (mean ± SE) was 46.4 ± 1.9%, in Zygnema sp. RVRED was only 34.3 ± 2.4% at the highest RH (∼95%) tested. This indicates a more pronounced water loss at higher RHs in K. crenulatum versus Zygnema sp. By contrast, at the lowest RH (∼4%) tested, RVRED ranged from 75.9 ± 2.7% in K. crenulatum to 83.9 ± 2.2% in Zygnema sp. The final volume reduction is therefore more drastic in Zygnema sp. These data contribute to our understanding of the desiccation process in streptophytic green algae, which are considered the closest ancestors of land plants. PMID:27075881

  9. Assessing the potential impact of water-based drill cuttings on deep-water calcareous red algae using species specific impact categories and measured oceanographic and discharge data.

    PubMed

    Nilssen, Ingunn; dos Santos, Francisco; Coutinho, Ricardo; Gomes, Natalia; Cabral, Marcelo Montenegro; Eide, Ingvar; Figueiredo, Marcia A O; Johnsen, Geir; Johnsen, Ståle

    2015-12-01

    The potential impact of drill cuttings on the two deep water calcareous red algae Mesophyllum engelhartii and Lithothamnion sp. from the Peregrino oil field was assessed. Dispersion modelling of drill cuttings was performed for a two year period using measured oceanographic and discharge data with 24 h resolution. The model was also used to assess the impact on the two algae species using four species specific impact categories: No, minor, medium and severe impact. The corresponding intervals for photosynthetic efficiency (ΦPSIImax) and sediment coverage were obtained from exposure-response relationship for photosynthetic efficiency as function of sediment coverage for the two algae species. The temporal resolution enabled more accurate model predictions as short-term changes in discharges and environmental conditions could be detected. The assessment shows that there is a patchy risk for severe impact on the calcareous algae stretching across the transitional zone and into the calcareous algae bed at Peregrino. PMID:26412110

  10. Sulfated Galactofucan from the Brown Alga Saccharina latissima—Variability of Yield, Structural Composition and Bioactivity

    PubMed Central

    Ehrig, Karina; Alban, Susanne

    2014-01-01

    The fucose-containing sulfated polysaccharides (SP) from brown algae exhibit a wide range of bioactivities and are, therefore, considered promising candidates for health-supporting and medicinal applications. A critical issue is their availability in high, reproducible quality. The aim of the present study was to fractionate and characterize the SP extracted from Saccharina latissima (S.l.-SP) harvested from two marine habitats, the Baltic Sea and North Atlantic Ocean, in May, June and September. The fractionation of crude S.l.-SP by anion exchange chromatography including analytical investigations revealed that S.l.-SP is composed of a homogeneous fraction of sulfated galactofucan (SGF) and a mixture of low-sulfated, uronic acid and protein containing heteropolysaccharides. Furthermore, the results indicated that S.l. growing at an intertidal zone with high salinity harvested at the end of the growing period delivered the highest yield of S.l.-SP with SGF as the main fraction (67%). Its SGF had the highest degree of sulfation (0.81), fucose content (86.1%) and fucose/galactose ratio (7.8) and was most active (e.g., elastase inhibition: IC50 0.21 μg/mL). Thus, S.l. from the North Atlantic harvested in autumn proved to be more appropriate for the isolation of S.l.-SP than S.l. from the Baltic Sea and S.l. harvested in spring, respectively. In conclusion, this study demonstrated that habitat and harvest time of brown algae should be considered as factors influencing the yield as well as the composition and thus also the bioactivity of their SP. PMID:25548975

  11. Draft Genome Sequence of a Novel Marine Bacterium, Paraglaciecola sp. Strain S66, with Hydrolytic Activity against Seaweed Polysaccharides

    PubMed Central

    Schultz-Johansen, Mikkel; Glaring, Mikkel A.; Bech, Pernille K.

    2016-01-01

    A novel agarolytic gammaproteobacterium, Paraglaciecola sp. S66, was isolated from marine samples of eelgrass (Zostera sp.) and sequenced. The draft genome contains a large number of enzyme-encoding genes with predicted function against several complex polysaccharides found in the cell walls of algae. PMID:27103729

  12. Mechanism of algal aggregation by Bacillus sp. strain RP1137.

    PubMed

    Powell, Ryan J; Hill, Russell T

    2014-07-01

    Alga-derived biofuels are one of the best alternatives for economically replacing liquid fossil fuels with a fungible renewable energy source. Production of fuel from algae is technically feasible but not yet economically viable. Harvest of dilute algal biomass from the surrounding water remains one of the largest barriers to economic production of algal biofuel. We identified Bacillus sp. strain RP1137 in a previous study and showed that this strain can rapidly aggregate several biofuel-producing algae in a pH- and divalent-cation-dependent manner. In this study, we further characterized the mechanism of algal aggregation by RP1137. We show that aggregation of both algae and bacteria is optimal in the exponential phase of growth and that the density of ionizable residues on the RP1137 cell surface changes with growth stage. Aggregation likely occurs via charge neutralization with calcium ions at the cell surface of both algae and bacteria. We show that charge neutralization occurs at least in part through binding of calcium to negatively charged teichoic acid residues. The addition of calcium also renders both algae and bacteria more able to bind to hydrophobic beads, suggesting that aggregation may occur through hydrophobic interactions. Knowledge of the aggregation mechanism may enable engineering of RP1137 to obtain more efficient algal harvesting. PMID:24771029

  13. Mechanism of Algal Aggregation by Bacillus sp. Strain RP1137

    PubMed Central

    Powell, Ryan J.

    2014-01-01

    Alga-derived biofuels are one of the best alternatives for economically replacing liquid fossil fuels with a fungible renewable energy source. Production of fuel from algae is technically feasible but not yet economically viable. Harvest of dilute algal biomass from the surrounding water remains one of the largest barriers to economic production of algal biofuel. We identified Bacillus sp. strain RP1137 in a previous study and showed that this strain can rapidly aggregate several biofuel-producing algae in a pH- and divalent-cation-dependent manner. In this study, we further characterized the mechanism of algal aggregation by RP1137. We show that aggregation of both algae and bacteria is optimal in the exponential phase of growth and that the density of ionizable residues on the RP1137 cell surface changes with growth stage. Aggregation likely occurs via charge neutralization with calcium ions at the cell surface of both algae and bacteria. We show that charge neutralization occurs at least in part through binding of calcium to negatively charged teichoic acid residues. The addition of calcium also renders both algae and bacteria more able to bind to hydrophobic beads, suggesting that aggregation may occur through hydrophobic interactions. Knowledge of the aggregation mechanism may enable engineering of RP1137 to obtain more efficient algal harvesting. PMID:24771029

  14. Selective fermentation of carbohydrate and protein fractions of Scenedesmus, and biohydrogenation of its lipid fraction for enhanced recovery of saturated fatty acids.

    PubMed

    Lai, YenJung Sean; Parameswaran, Prathap; Li, Ang; Aguinaga, Alyssa; Rittmann, Bruce E

    2016-02-01

    Biofuels derived from microalgae have promise as carbon-neutral replacements for petroleum. However, difficulty extracting microalgae-derived lipids and the co-extraction of non-lipid components add major costs that detract from the benefits of microalgae-based biofuel. Selective fermentation could alleviate these problems by managing microbial degradation so that carbohydrates and proteins are hydrolyzed and fermented, but lipids remain intact. We evaluated selective fermentation of Scenedesmus biomass in batch experiments buffered at pH 5.5, 7, or 9. Carbohydrates were fermented up to 45% within the first 6 days, protein fermentation followed after about 20 days, and lipids (measured as fatty acid methyl esters, FAME) were conserved. Fermentation of the non-lipid components generated volatile fatty acids, with acetate, butyrate, and propionate being the dominant products. Selective fermentation of Scenedesmus biomass increased the amount of extractable FAME and the ratio of FAME to crude lipids. It also led to biohydrogenation of unsaturated FAME to more desirable saturated FAME (especially to C16:0 and C18:0), and the degree of saturation was inversely related to the accumulation of hydrogen gas after fermentation. Moreover, the microbial communities after selective fermentation were enriched in bacteria from families known to perform biohydrogenation, i.e., Porphyromonadaceae and Ruminococcaceae. Thus, this study provides proof-of-concept that selective fermentation can improve the quantity and quality of lipids that can be extracted from Scenedesmus. PMID:26222672

  15. Cultivation of macroscopic marine algae

    SciTech Connect

    Ryther, J.H.

    1982-11-01

    The red alga Gracilaria tikvahiae may be grown outdoors year-round in central Florida with yields averaging 35.5 g dry wt/m/sup 2/.day, greater than the most productive terrestrial plants. This occurs only when the plants are in a suspended culture, with vigorous aeration and an exchange of 25 or more culture volumes of enriched seawater per day, which is not cost-effective. A culture system was designed in which Gracilaria, stocked at a density of 2 kg wet wt/m/sup 2/, grows to double its biomass in one to two weeks; it is then harvested to its starting density, and anaerobically digested to methane. The biomass is soaked for 6 hours in the digester residue, storing enough nutrients for two weeks' growth in unenriched seawater. The methane is combusted for energy and the waste gas is fed to the culture to provide mixing and CO/sub 2/, eliminating the need for aeration and seawater exchange. The green alga Ulva lactuca, unlike Gracilaria, uses bicarbonate as a photosynthesis carbon source, and can grow at high pH, with little or no free CO/sub 2/. It can therefore produce higher yields than Gracilaria in low water exchange conditions. It is also more efficiently converted to methane than is Gracilaria, but cannot tolerate Florida's summer temperatures so cannot be grown year-round. Attempts are being made to locate or produce a high-temperature tolerant strain.

  16. Take a Dip! Culturing Algae Is Easy.

    ERIC Educational Resources Information Center

    James, Daniel E.

    1983-01-01

    Describes laboratory activities using algae as the organisms of choice. These include examination of typical algal cells, demonstration of alternation of generations, sexual reproduction in Oedogonium, demonstration of phototaxis, effect of nitrate concentration on Ankistrodesmus, and study of competition between two algae in the same environment.…

  17. SSMILes: Measuring the Nutrient Tolerance of Algae.

    ERIC Educational Resources Information Center

    Hedgepeth, David J.

    1995-01-01

    Presents an activity integrating mathematics and science intended to introduce students to the use of metric measurement of mass as a way to increase the meaningfulness of observations about variables in life sciences. Involves measuring the nutrient tolerance of algae. Contains a reproducible algae nutrient graph. (Author/MKR)

  18. Effect of Dead Algae on Soil Permeability

    SciTech Connect

    Harvey, R.S.

    2003-02-21

    Since existing basins support heavy growths of unicellular green algae which may be killed by temperature variation or by inadvertent pH changes in waste and then deposited on the basin floor, information on the effects of dead algae on soil permeability was needed. This study was designed to show the effects of successive algal kills on the permeability of laboratory soil columns.

  19. Hydrogen metabolism of photosynthetic bacteria and algae

    SciTech Connect

    Kumazawa, S.; Mitsui, A.

    1982-01-01

    The metabolism, metabolic pathways and biochemistry of hydrogen in photosynthetic bacteria and algae are reviewed. Detailed information on the occurrence and measurement of hydrogenase activity is presented. Hydrogen production rates for different species of algae and bacteria are presented. 173 references, 1 figure, 7 tables.

  20. Flocculation of model algae under shear.

    SciTech Connect

    Pierce, Flint; Lechman, Jeremy B.

    2010-11-01

    We present results of molecular dynamics simulations of the flocculation of model algae particles under shear. We study the evolution of the cluster size distribution as well as the steady-state distribution as a function of shear rates and algae interaction parameters. Algal interactions are modeled through a DLVO-type potential, a combination of a HS colloid potential (Everaers) and a yukawa/colloid electrostatic potential. The effect of hydrodynamic interactions on aggregation is explored. Cluster strucuture is determined from the algae-algae radial distribution function as well as the structure factor. DLVO parameters including size, salt concentration, surface potential, initial volume fraction, etc. are varied to model different species of algae under a variety of environmental conditions.

  1. Composting of waste algae: a review.

    PubMed

    Han, Wei; Clarke, William; Pratt, Steven

    2014-07-01

    Although composting has been successfully used at pilot scale to manage waste algae removed from eutrophied water environments and the compost product applied as a fertiliser, clear guidelines are not available for full scale algae composting. The review reports on the application of composting to stabilize waste algae, which to date has mainly been macro-algae, and identifies the peculiarities of algae as a composting feedstock, these being: relatively low carbon to nitrogen (C/N) ratio, which can result in nitrogen loss as NH3 and even N2O; high moisture content and low porosity, which together make aeration challenging; potentially high salinity, which can have adverse consequence for composting; and potentially have high metals and toxin content, which can affect application of the product as a fertiliser. To overcome the challenges that these peculiarities impose co-compost materials can be employed. PMID:24602833

  2. 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.

  3. Streptophyte algae and the origin of embryophytes

    PubMed Central

    Becker, Burkhard; Marin, Birger

    2009-01-01

    Background Land plants (embryophytes) evolved from streptophyte green algae, a small group of freshwater algae ranging from scaly, unicellular flagellates (Mesostigma) to complex, filamentous thalli with branching, cell differentiation and apical growth (Charales). Streptophyte algae and embryophytes form the division Streptophyta, whereas the remaining green algae are classified as Chlorophyta. The Charales (stoneworts) are often considered to be sister to land plants, suggesting progressive evolution towards cellular complexity within streptophyte green algae. Many cellular (e.g. phragmoplast, plasmodesmata, hexameric cellulose synthase, structure of flagellated cells, oogamous sexual reproduction with zygote retention) and physiological characters (e.g. type of photorespiration, phytochrome system) originated within streptophyte algae. Recent Progress Phylogenetic studies have demonstrated that Mesostigma (flagellate) and Chlorokybus (sarcinoid) form the earliest divergence within streptophytes, as sister to all other Streptophyta including embryophytes. The question whether Charales, Coleochaetales or Zygnematales are the sister to embryophytes is still (or, again) hotly debated. Projects to study genome evolution within streptophytes including protein families and polyadenylation signals have been initiated. In agreement with morphological and physiological features, many molecular traits believed to be specific for embryophytes have been shown to predate the Chlorophyta/Streptophyta split, or to have originated within streptophyte algae. Molecular phylogenies and the fossil record allow a detailed reconstruction of the early evolutionary events that led to the origin of true land plants, and shaped the current diversity and ecology of streptophyte green algae and their embryophyte descendants. Conclusions The Streptophyta/Chlorophyta divergence correlates with a remarkably conservative preference for freshwater/marine habitats, and the early freshwater

  4. Balamuthia mandrillaris: in vitro interactions with selected protozoa and algae.

    PubMed

    Tapia, José L; Torres, Benjamin Nogueda; Visvesvara, Govinda S

    2013-01-01

    Although Balamuthia mandrillaris was identified more than two decades ago as an agent of fatal granulomatous encephalitis in humans and other animals, little is known about its ecological niche, biological behavior in the environment, food preferences and predators, if any. When infecting humans or other animals, Balamuthia feeds on tissues; and in vitro culture, it feeds on mammalian cells (monkey kidney cells, human lung fibroblasts, and human microvascular endothelial cells). According to recent reports, it is believed that Balamuthia feeds on small amebae, for example, Acanthamoeba that are present in its ecological niche. To test this hypothesis, we associated Balamuthia on a one-on-one basis with selected protozoa and algae. We videotaped the behavior of Balamuthia in the presence of a potential prey, its ability to hunt and attack its food, and the time required to eat and cause damage to the target cell by direct contact. We found that B. mandrillaris ingested trophozoites of Naegleria fowleri, Naegleria gruberi, Acanthamoeba spp., Trypanosoma cruzi epimastigotes, Toxoplasma gondii tachyzoites, and Giardia. However, it did not feed on Acanthamoeba cysts or algae. Balamuthia caused cytolysis of T. cruzi epimastigotes and T. gondii tachyzoites by direct contact. Balamuthia trophozoites and cysts were, however, eaten by Paramecium sp. PMID:23790262

  5. Biotransformation of arsenic by a Yellowstone thermoacidophilic eukaryotic alga

    PubMed Central

    Qin, Jie; Lehr, Corinne R.; Yuan, Chungang; Le, X. Chris; McDermott, Timothy R.; Rosen, Barry P.

    2009-01-01

    Arsenic is the most common toxic substance in the environment, ranking first on the Superfund list of hazardous substances. It is introduced primarily from geochemical sources and is acted on biologically, creating an arsenic biogeocycle. Geothermal environments are known for their elevated arsenic content and thus provide an excellent setting in which to study microbial redox transformations of arsenic. To date, most studies of microbial communities in geothermal environments have focused on Bacteria and Archaea, with little attention to eukaryotic microorganisms. Here, we show the potential of an extremophilic eukaryotic alga of the order Cyanidiales to influence arsenic cycling at elevated temperatures. Cyanidioschyzon sp. isolate 5508 oxidized arsenite [As(III)] to arsenate [As(V)], reduced As(V) to As(III), and methylated As(III) to form trimethylarsine oxide (TMAO) and dimethylarsenate [DMAs(V)]. Two arsenic methyltransferase genes, CmarsM7 and CmarsM8, were cloned from this organism and demonstrated to confer resistance to As(III) in an arsenite hypersensitive strain of Escherichia coli. The 2 recombinant CmArsMs were purified and shown to transform As(III) into monomethylarsenite, DMAs(V), TMAO, and trimethylarsine gas, with a Topt of 60–70 °C. These studies illustrate the importance of eukaryotic microorganisms to the biogeochemical cycling of arsenic in geothermal systems, offer a molecular explanation for how these algae tolerate arsenic in their environment, and provide the characterization of algal methyltransferases. PMID:19276121

  6. Antiherpetic activities of sulfated polysaccharides from green algae.

    PubMed

    Lee, Jung-Bum; Hayashi, Kyoko; Maeda, Masaakira; Hayashi, Toshimitsu

    2004-09-01

    In order to evaluate the potency of novel antiviral drugs, 11 natural sulfated polysaccharides (SPs) from 10 green algae ( Enteromorpha compressa, Monostroma nitidum, Caulerpa brachypus, C. okamurai, C. scapelliformis, Chaetomorpha crassa, C. spiralis, Codium adhaerens, C. fragille, and C. latum) and 4 synthetic sulfated xylans (SXs) prepared from the beta-(1,3)-xylan of C. brachypus, were assayed for anti-Herpes simplex virus type 1 (HSV-1) activity. Except for one from E. compressa, all SPs showed potent anti-HSV-1 activities with 50 % inhibitory concentrations (IC (50)) of 0.38 - 8.5 microg/mL, while having low cytotoxicities with 50 % inhibitory concentrations of >2900 microg/mL. Anti-HSV-1 activities of SXs were dependent on their degrees of sulfation. To delineate the drug-sensitive phase, 4 polysaccharides, which showed potent anti-HSV-1 activities, were applied to time-of-addition experiments. Among the polysaccharides tested, 3 polysaccharides (SX4, SP4 from C. brachypus, and SP11 from C. latum) showed strong anti-HSV-1 activities with IC (50) of 6.0, 7.5, and 6.9 microg/mL, respectively, even when added to the medium 8 h post-infection. These experiments demonstrated that some sulfated polysaccharides not only inhibited the early stages of HSV-1 replication, such as virus binding to and penetration into host cells, but also interfered with late steps of virus replication. These results revealed that some sulfated polysaccharides from green algae should be promising candidates of antiviral agents which might act on different stages in the virus replication cycle. PMID:15386190

  7. 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

  8. Algae biodiesel - a feasibility report

    PubMed Central

    2012-01-01

    Background Algae biofuels have been studied numerous times including the Aquatic Species program in 1978 in the U.S., smaller laboratory research projects and private programs. Results Using Molina Grima 2003 and Department of Energy figures, captial costs and operating costs of the closed systems and open systems were estimated. Cost per gallon of conservative estimates yielded $1,292.05 and $114.94 for closed and open ponds respectively. Contingency scenarios were generated in which cost per gallon of closed system biofuels would reach $17.54 under the generous conditions of 60% yield, 50% reduction in the capital costs and 50% hexane recovery. Price per gallon of open system produced fuel could reach $1.94 under generous assumptions of 30% yield and $0.2/kg CO2. Conclusions Current subsidies could allow biodiesel to be produced economically under the generous conditions specified by the model. PMID:22540986

  9. Algae Biofuel in the Nigerian Energy Context

    NASA Astrophysics Data System (ADS)

    Elegbede, Isa; Guerrero, Cinthya

    2016-05-01

    The issue of energy consumption is one of the issues that have significantly become recognized as an important topic of global discourse. Fossil fuels production reportedly experiencing a gradual depletion in the oil-producing nations of the world. Most studies have relatively focused on biofuel development and adoption, however, the awareness of a prospect in the commercial cultivation of algae having potential to create economic boost in Nigeria, inspired this research. This study aims at exploring the potential of the commercialization of a different but commonly found organism, algae, in Nigeria. Here, parameters such as; water quality, light, carbon, average temperature required for the growth of algae, and additional beneficial nutrients found in algae were analysed. A comparative cum qualitative review of analysis was used as the study made use of empirical findings on the work as well as the author's deductions. The research explored the cultivation of algae with the two major seasonal differences (i.e. rainy and dry) in Nigeria as a backdrop. The results indicated that there was no significant difference in the contribution of algae and other sources of biofuels as a necessity for bioenergy in Nigeria. However, for an effective sustainability of this prospect, adequate measures need to be put in place in form of funding, provision of an economically-enabling environment for the cultivation process as well as proper healthcare service in the face of possible health hazard from technological processes. Further studies can seek to expand on the potential of cultivating algae in the Harmattan season.

  10. Metagenome Survey of a Multispecies and Alga-Associated Biofilm Revealed Key Elements of Bacterial-Algal Interactions in Photobioreactors

    PubMed Central

    Krohn-Molt, Ines; Wemheuer, Bernd; Alawi, Malik; Poehlein, Anja; Güllert, Simon; Schmeisser, Christel; Pommerening-Röser, Andreas; Grundhoff, Adam; Daniel, Rolf; Hanelt, Dieter

    2013-01-01

    Photobioreactors (PBRs) are very attractive for sunlight-driven production of biofuels and capturing of anthropogenic CO2. One major problem associated with PBRs however, is that the bacteria usually associated with microalgae in nonaxenic cultures can lead to biofouling and thereby affect algal productivity. Here, we report on a phylogenetic, metagenome, and functional analysis of a mixed-species bacterial biofilm associated with the microalgae Chlorella vulgaris and Scenedesmus obliquus in a PBR. The biofilm diversity and population dynamics were examined through 16S rRNA phylogeny. Overall, the diversity was rather limited, with approximately 30 bacterial species associated with the algae. The majority of the observed microorganisms were affiliated with Alphaproteobacteria, Betaproteobacteria, and Bacteroidetes. A combined approach of sequencing via GS FLX Titanium from Roche and HiSeq 2000 from Illumina resulted in the overall production of 350 Mbp of sequenced DNA, 165 Mbp of which was assembled in larger contigs with a maximum size of 0.2 Mbp. A KEGG pathway analysis suggested high metabolic diversity with respect to the use of polymers and aromatic and nonaromatic compounds. Genes associated with the biosynthesis of essential B vitamins were highly redundant and functional. Moreover, a relatively high number of predicted and functional lipase and esterase genes indicated that the alga-associated bacteria are possibly a major sink for lipids and fatty acids produced by the microalgae. This is the first metagenome study of microalga- and PBR-associated biofilm bacteria, and it gives new clues for improved biofuel production in PBRs. PMID:23913425

  11. Quantitative structure-activity analysis of the algae toxicity of nitroaromatic compounds.

    PubMed

    Schmitt, H; Altenburger, R; Jastorff, B; Schüürmann, G

    2000-06-01

    Proliferation toxicity toward the algae Scenedesmus vacuolatus in a 24 h one-generation reproduction assay was determined for nitrobenzene and 18 derivatives, including two phenols. The resultant EC(50) values covering more than 4 orders of magnitude were subjected to a quantitative structure-activity analysis (QSAR) using hydrophobicity in terms of the octanol/water partition coefficient in logarithmic form, log K(ow), and 16 quantum chemical descriptors of molecular reactivity that were calculated with the AM1 scheme. For 13 mononitro derivatives and the highly hydrophobic trifluralin, a narcotic-type mode of action can explain most of the toxicity variation. Correction of log K(ow) for ionization for the phenols and quantification of the molecular susceptibility for one-electron reduction as apparently rate-determining biotransformation step by the energy of the lowest unoccupied molecular orbital, E(LUMO), yields a highly significant QSAR for all 19 compounds (r(adj)(2) = 0.90), which can be further improved when adding the maximum net atomic charge at the nitro nitrogen, q(nitro)(-)(N), as the third descriptor (r(adj)(2) = 0.93). Comparison of the energy of the singly occupied molecular orbital, E(SOMO), of the radical anions as initial metabolites with the E(SOMO) of known redox cyclers suggests that dinitrobenzenes and TFM as well as multiply chlorinated nitrobenzenes may also exert oxidative stress. This is based on an E(SOMO) window of -0.30 to 0. 55 eV as a tentative criterion for molecular structures to have the potential for redox cycling, derived from a set of eight known redox cyclers. The discussion includes a detailed analysis of apparently relevant metabolic pathways and associated modes of toxic action of nitroaromatics. PMID:10858317

  12. Method and apparatus for processing algae

    DOEpatents

    Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite; Di Salvo, Roberto

    2012-07-03

    Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells. The lysate separates into at least two layers including a lipid-containing hydrophobic layer and an ionic liquid-containing hydrophilic layer. A salt or salt solution may be used to remove water from the ionic liquid-containing layer before the ionic liquid is reused. The used salt may also be dried and/or concentrated and reused. The method can operate at relatively low lysis, processing, and recycling temperatures, which minimizes the environmental impact of algae processing while providing reusable biofuels and other useful products.

  13. Errors When Extracting Oil from Algae

    NASA Astrophysics Data System (ADS)

    Murphy, E.; Treat, R.; Ichiuji, T.

    2014-12-01

    Oil is in popular demand, but the worldwide amount of oil is decreasing and prices for it are steadily increasing. Leading scientists have been working to find a solution of attaining oil in an economically and environmentally friendly way. Researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL) have determined that "a small mixture of algae and water can be turned into crude oil in less than an hour" (Sheehan, Duhahay, Benemann, Poessler). There are various ways of growing the algae, such as closed loop and open loop methods, as well as processes of extracting oil, such as hydrothermal liquefaction and the hexane-solvent method. Our objective was to grow the algae (C. reinhardtii) and extract oil from it using NaOH and HCl, because we had easy access to those specific chemicals. After two trials of attempted algae growth, we discovered that a bacteria was killing off the algae. This led us to further contemplation on how this dead algae and bacteria are affecting our environment, and the organisms within it. Eutrophication occurs when excess nutrients stimulate rapid growth of algae in an aquatic environment. This can clog waterways and create algal blooms in blue-green algae, as well as neurotoxic red tide phytoplankton. These microscopic algae die upon consumption of the nutrients in water and are degraded by bacteria. The bacteria respires and creates an acidic environment with the spontaneous conversion of carbon dioxide to carbonic acid in water. This process of degradation is exactly what occurred in our 250 mL flask. When the phytoplankton attacked our algae, it created a hypoxic environment, which eliminated any remaining amounts of oxygen, carbon dioxide, and nutrients in the water, resulting in a miniature dead zone. These dead zones can occur almost anywhere where there are algae and bacteria, such as the ocean, and make it extremely difficult for any organism to survive. This experiment helped us realize the

  14. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  15. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  16. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  17. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  18. Effect of carbon source on biomass growth and nutrients removal of Scenedesmus obliquus for wastewater advanced treatment and lipid production.

    PubMed

    Shen, Qiao-Hui; Jiang, Jia-Wei; Chen, Li-Ping; Cheng, Li-Hua; Xu, Xin-Hua; Chen, Huan-Lin

    2015-08-01

    The combination of tertiary wastewater treatment and microalgal lipid production is considered to be a promising approach to water eutrophication as well as energy crisis. To intensify wastewater treatment and microalgal biofuel production, the effect of organic and inorganic carbon on algal growth and nutrient removal of Scenedesmus obliquus were examined by varying TOC (total organic carbon) concentrations of 20-120mgL(-1) in wastewater and feeding CO2 concentrations in the range of 0.03-15%, respectively. The results showed that the maximal biomass and average lipid productivity were 577.6 and 16.7mgL(-1)d(-1) with 5% CO2 aeration. The total nitrogen, total phosphorus and TOC removal efficiencies were 97.8%, 95.6% and 59.1% respectively within 6days when cultured with real secondary municipal wastewater. This work further showed that S. obliquus could be utilized for simultaneous organic pollutants reduction, N, P removal and lipid accumulation. PMID:25958150

  19. Influence of abscisic acid on growth, biomass and lipid yield of Scenedesmus quadricauda under nitrogen starved condition.

    PubMed

    Sulochana, Sujitha Balakrishnan; Arumugam, Muthu

    2016-08-01

    Scenedesmus quadricauda, accumulated more lipid but with a drastic reduction in biomass yield during nitrogen starvation. Abscisic acid (ABA) being a stress responsible hormone, its effect on growth and biomass with sustainable lipid yield during nitrogen depletion was studied. The result revealed that the ABA level shoots up at 24h (27.21pmol/L) during the onset of nitrogen starvation followed by a sharp decline. The external supplemented ABA showed a positive effect on growth pattern (38×10(6)cells/ml) at a lower concentration. The dry biomass yield is also increasing up to 2.1 fold compared to nitrogen deficient S. quadricauda. The lipid content sustains in 1 and 2μM concentration of ABA under nitrogen-deficient condition. The fatty acid composition of ABA treated S. quadricauda cultures with respect to nitrogen-starved cells showed 11.17% increment in saturated fatty acid content, the desired lipid composition for biofuel application. PMID:26949054

  20. Influence of light presence and biomass concentration on nutrient kinetic removal from urban wastewater by Scenedesmus obliquus.

    PubMed

    Ruiz, J; Arbib, Z; Alvarez-Díaz, P D; Garrido-Pérez, C; Barragán, J; Perales, J A

    2014-05-20

    This work was aimed at studying the effect of light-darkness and high-low biomass concentrations in the feasibility of removing nitrogen and phosphorus from urban treated wastewater by the microalga Scenedesmus obliquus. Laboratory experiments were conducted in batch, where microalgae were cultured under different initial biomass concentrations (150 and 1500mgSSl(-1)) and light conditions (dark or illuminated). Nutrient uptake was more dependent on internal nutrient content of the biomass than on light presence or biomass concentration. When a maximum nitrogen or phosphorus content in the biomass was reached (around 8% and 2%, respectively), the removal of that nutrient was almost stopped. Biomass concentration affected more than light presence on the nutrient removal rate, increasing significantly with its increase. Light was only required to remove nutrients when the maximum nutrient storage capacity of the cells was reached and further growth was therefore needed. Residence times to maintain a stable biomass concentration, avoiding the washout of the reactor, were much higher than those needed to remove the nutrients from the wastewater. This ability to remove nutrients in the absence of light could lead to new configurations of reactors aimed to wastewater treatment. PMID:24631723

  1. Expression of type 2 diacylglycerol acyltransferse gene DGTT1 from Chlamydomonas reinhardtii enhances lipid production in Scenedesmus obliquus.

    PubMed

    Chen, Chun-Yen; Kao, Ai-Ling; Tsai, Zheng-Chia; Chow, Te-Jin; Chang, Hsin-Yueh; Zhao, Xin-Qing; Chen, Po-Ting; Su, Hsiang-Yen; Chang, Jo-Shu

    2016-03-01

    Microalgal strains of Scenedesmus obliquus have the great potential for the production of biofuels, CO2 fixation, and bioremediation. However, metabolic engineering of S. obliquus to improve their useful phenotypes are still not fully developed. In this study, S. obliquus strain CPC2 was genetically engineered to promote the autotrophic growth and lipid productivity. The overexpression plasmid containing the type 2 diacylglycerol acyltransferse (DGAT) gene DGTT1 from Chlamydomonas reinhardtii was constructed and transformed into S. obliquus CPC2, and the positive transformants were obtained. The expression of DGTT1 gene was confirmed by reverse transcription PCR analysis. Enhanced lipid content of the transformant S. obliquus CPC2-G1 by nearly two-fold was observed. The biomass concentration of the recombinant strains was also 29% higher than that of the wild-type strain. Furthermore, the recombinant strain CPC2-G1 was successfully grown in 40 L tubular type photobioreactor and open pond system in an outdoor environment. The lipid content, biomass concentration, and biomass productivity obtained from 40 L tubular PBR were 127.8% 20.0%, and 232.6% higher than those obtained from the wild-type strain. The major aim of this work is to develop a tool to genetically engineer an isolated S. obliquus strain for the desired purpose. This is the first report that genetic engineering of S. obliquus has been successful employed to improve both the microalgal cell growth and the lipid production. PMID:26849021

  2. Improvement of stability and carotenoids fraction of virgin olive oils by addition of microalgae Scenedesmus almeriensis extracts.

    PubMed

    Limón, Piedad; Malheiro, Ricardo; Casal, Susana; Acién-Fernández, F Gabriel; Fernández-Sevilla, José M; Rodrigues, Nuno; Cruz, Rebeca; Bermejo, Ruperto; Pereira, José Alberto

    2015-05-15

    Humans are not capable of synthesizing carotenoids de novo and thus, their presence in human tissues is entirely of dietary origin. Consumption of essential carotenoids is reduced due to the lower intake of fruits and vegetables. Microalgae are a good source of carotenoids that can be exploited. In the present work, carotenoids rich extracts from Scenedesmus almeriensis were added to extra-virgin olive oils at different concentrations (0.1 and 0.21 mg/mL) in order to enhance the consumption of these bioactives. Extracts brought changes in olive oils color, turning them orange-reddish. Quality of olive oils was improved, since peroxidation was inhibited. Olive oils fatty acids and tocopherols were not affected. β-carotene and lutein contents increase considerably, as well as oxidative stability, improving olive oils shelf-life and nutritional value. Inclusion of S. almeriensis extracts is a good strategy to improve and enhance the consumption of carotenoids, since olive oil consumption is increasing. PMID:25577071

  3. Post-coital contraceptive activity of crude extracts of Sri Lankan marine red algae.

    PubMed

    Ratnasooriya, W D; Premakumara, G A; Tillekeratne, L M

    1994-09-01

    This study investigates the potential of marine red algae as a source for post-coital contraceptive agents using three varieties: Gracilaria corticata, Gelidiella acerosa and Jania sp. Methanol: methylene chloride (1:1) extracts of these red algae were made and were orally administered (500 or 1000 mg/kg/day) to female rats from day 1 to day 7 of pregnancy. The higher dose of Gracilaria corticata and both doses of Gelidiella acerosa extracts produced significant post-coital contraceptive activities without any marked side effects. Furthermore, the post-coital contraceptive activity of the latter extract was dose-dependent. On the other hand, extract made from Jania sp. had no significant post-coital contraceptive action. The post-coital contraceptive activity of Gracilaria corticata was due to enhanced pre-implantation loss and of Gelidiella acerosa was due to elevated post-implantation loss. These findings indicate that marine red algae is a useful source to be harvested for potential post-coital contraceptive drugs. PMID:7805379

  4. Larval settlement preferences of Acropora palmata and Montastraea faveolata in response to diverse red algae

    NASA Astrophysics Data System (ADS)

    Ritson-Williams, R.; Arnold, S. N.; Paul, V. J.; Steneck, R. S.

    2014-03-01

    Settlement specificity can regulate recruitment but remains poorly understood for coral larvae. We studied larvae of the corals, Acropora palmata and Montastraea faveolata, to determine their rates of settlement and metamorphosis in the presence of ten species of red algae, including eight species of crustose coralline algae, one geniculated coralline and one encrusting peyssonnelid. Twenty to forty percent of larvae of A. palmata settled on coralline surfaces of Hydrolithon boergesenii, Lithoporella atlantica, Neogoniolithon affine, and Titanoderma prototypum, whereas none settled and metamorphosed on Neogoniolithon mamillare. Larvae of M. faveolata had 13-25 % settlement onto the surface of Amphiroa tribulus, H. boergesenii, N. affine, N. munitum, and T. prototypum, but had no settlement on the surface of N. mamillare, Porolithon pachydermum, and a noncoralline crust Peyssonnelia sp. Some of these algal species were common on Belizean reefs, but the species that induced the highest rates of larval settlement and metamorphosis tended to be rare and primarily found in low-light environments. The shallow coral, A. palmata, and the deeper coral, M. faveolata, both had increased larval settlement rates in the presence of only a few species of red algae found at deeper depths suggesting that patterns of coral distribution can only sometimes be related to the distribution of red algae species.

  5. Laboratory study on the ecological impact of sophorolipid used for harmful algae elimination

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoxia; Kim, Eunki; Sun, Song

    2010-11-01

    We studied the role of sophorolipid in inhibiting harmful algae bloom (HAB). Different sophorolipid concentrations were tested on marine microalgae, zooplankton, fish, and bivalve ( Mytilus edulis) in laboratory. The result shows that sophorolipid could inhibit the growth of algal species selectively. Among three algae species selected, Platymonas helgolandica var. tsingtaoensis was promoted with increasing sophorolipid concentration; Isochrysis galbana was inhibited seven days later in sophorolipid concentration below 40 mg/L; and Nitzschia closterium f. minutissima was inhibited obviously in only a high sophorolipid concentration over 20 mg/L. Therefore, sophorolipid in a low concentration at <20 mg/L could remove certain harmful algae species effectively without harming other non-harmful microalgae. For other animals, sophorolipid could inhibit the growth of ciliate Strombidium sp. by 50% at 20 mg/L sophorolipid concentration after 96 h. The concentration in 96-h LC50 for Calanus sinicus, Neomysis awatschensis, Lateolabrax japonicus, and Paralichthys olivaceus was 15, 150, 60, and 110 mg/L, respectively. The 24 h LC50 value for Artemia salina was 600 mg/L. The relative clearance rate of mussel Mytilus edulis decreased to 80%, 40%, and 20% of the control group after being exposed to 20, 50, and 100 mg/L sophorolipid for 24 h. Therefore, the toxicity for mitigation of harmful algae bloom at previously recommended concentration of 5-20 mg/L sophorolipid is low for most tested organisms in this reaserch.

  6. Removal of Cr{sup 6+} from waste water by dead cells of Pachymeniopsis sp.

    SciTech Connect

    Jeong, Y.H.; Yang, J.E.; Rhee, H.I.

    1995-12-31

    A red algae, Pachymeniopsis sp., was screened as a Cr{sup +6} specific biosorbent and its adsorption characteristics for Cr{sup +6} were studied. It is well known that several heavy metal ions such as cadmium, nickel, mercury can be selectively adsorbed by some specific marine algae. However, so far there has been no report that the biosorbent specific for Cr{sup +6} adsorption was successfully developed. Thus, trials of searching for a high Cr{sup +6} selective biosorbent with high adsorption capacity were made by examination of the Cr{sup +6} adsorption capacities of about fifty species of red, brown, or green marine algae which were sampled from the east coast of Korea. As the result of screening, a red marine algae showed most excellent adsorption characteristics among them and it was classified as Pachymeniopsis sp. Adsorption isotherms and adsorption kinetics were investigated to examine the applicability of Pachymeniopsis sp. as a Cr{sup +6} specific biosorbent. Pachymeniopsis sp. showed high selectivity for Cr{sup +6} ions since it showed low adsorption capacities for other heavy metal ions such as cadmium and manganese ions. An investigation of adsorption isotherms of dried powder of the Pachymeniopsis sp. for Cr{sup +6} adsorption at 25 C, pH 5.0 and 7.0 showed Langmuir type dependence. The isotherms show that the maximum Cr{sup +6} adsorption capacity of selected algae is about 20 (mg/g dry wt. of adsorbent). The 500 ml of artificial waste water with initial Cr{sup +6} concentration of 100 ppm was treated with 2.5 g of dried powder of Pachymeniopsis sp. in a batch slurry reactor. About 30 ppm of Cr{sup +6} remained after 1 hr`s contacting, showing 70% removal of Cr{sup +6}.

  7. Collection, Isolation and Culture of Marine Algae.

    ERIC Educational Resources Information Center

    James, Daniel E.

    1984-01-01

    Methods of collecting, isolating, and culturing microscopic and macroscopic marine algae are described. Three different culture media list of chemicals needed and procedures for preparing Erdschreiber's and Provasoli's E. S. media. (BC)

  8. Pyogenic Flexor Tenosynovitis Caused by Shewanella algae.

    PubMed

    Fluke, Erin C; Carayannopoulos, Nikoletta L; Lindsey, Ronald W

    2016-07-01

    Pyogenic flexor tenosynovitis is an orthopedic emergency most commonly caused by Staphylococcus aureus and streptococci and occasionally, when associated with water exposure, Mycobacterium marinum. Shewanella algae, a gram-negative bacillus found in warm saltwater environments, has infrequently been reported to cause serious soft tissue infections and necrosis. In this case, S. algae caused complicated flexor tenosynovitis requiring open surgical irrigation and debridement. Flexor tenosynovitis caused by S. algae rapidly presented with all 4 Kanavel cardinal signs as well as subcutaneous purulence, ischemia, and necrosis, thus meeting the requirements for Pang et al group III classification of worst prognosis. Because of its rarity and virulence, S. algae should always be considered in cases of flexor tenosynovitis associated with traumatic water exposure to treat and minimize morbidity appropriately. PMID:27206398

  9. 2011 Biomass Program Platform Peer Review: Algae

    SciTech Connect

    Yang, Joyce

    2012-02-01

    This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the 2011 U.S. Department of Energy Biomass Program’s Algae Platform Review meeting.

  10. 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

  11. The Alga Ochromonas danica Produces Bromosulfolipids.

    PubMed

    White, Alexander R; Duggan, Brendan M; Tsai, Shiou-Chuan; Vanderwal, Christopher D

    2016-03-01

    Many halogenases interchangeably incorporate chlorine and bromine into organic molecules. On the basis of an unsubstantiated report that the alga Ochromonas danica, a prodigious producer of chlorosulfolipids, was able to produce bromosulfolipids, we have investigated the promiscuity of its halogenases toward bromine incorporation. We have found that bromosulfolipids are produced with the exact positional and stereochemical selectivity as in the chlorosulfolipid danicalipin A when this alga is grown under modified conditions containing excess bromide ion. PMID:26889956

  12. Stochastic Forecasting of Algae Blooms in Lakes

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.

    2013-01-03

    We consider a general framework to predict the development of harmful algal blooms (HABs) in a lake driven by uncertain parameters. To quantify the concentration uncertainty of those algae groups via their joint probabilistic density function (PDF), we explore an approach based on the Fokker-Planck equation. Our result is presented in an example where abundant nutrients contribute to the proliferation of cyanobacteria and other minor algae groups.

  13. Aliterella atlantica gen. nov., sp. nov., and Aliterella antarctica sp. nov., novel members of coccoid Cyanobacteria.

    PubMed

    Rigonato, Janaina; Gama, Watson Arantes; Alvarenga, Danillo Oliveira; Branco, Luis Henrique Zanini; Brandini, Frederico Pereira; Genuário, Diego Bonaldo; Fiore, Marli Fatima

    2016-09-01

    Two Cyanobacteria isolated from South Atlantic Ocean continental shelf deep water and from a marine green algae inhabiting the Admiralty Bay, King George Island, Antarctica were investigated based on morphological and ultrastructural traits, phylogeny of 16S rRNA gene sequences, secondary structure of the 16S-23S internal transcribed spacer regions and phylogenomic analyses. The majority of these evaluations demonstrated that both strains differ from the genera of cyanobacteria with validly published names and, therefore, supported the description of the novel genus as Aliterella gen. nov. The identity and phylogeny of 16S rRNA gene sequences, together with the secondary structure of D1D1' and BoxB intergenic regions, further supported the two strains representing distinct species: Aliterella atlantica gen. nov., sp. nov. (type SP469036, strain CENA595T) and Aliterella antarctica sp. nov. (type SP469035, strain CENA408T). The phylogenomic analysis of A. atlantica sp. nov. CENA595T, based on 21 protein sequences, revealed that this genus belongs to the cyanobacterial order Chroococcidiopsidales. The isolation and cultivation of two geographically distant unicellular members of a novel cyanobacterial genus and the sequenced genome of the type strain bring new insights into the current classification of the coccoid group, and into the reconstruction of their evolutionary history. PMID:27054834

  14. Occurrence of arsenic species in algae and freshwater plants of an extreme arid region in northern Chile, the Loa River Basin.

    PubMed

    Pell, Albert; Márquez, Anna; López-Sánchez, José Fermín; Rubio, Roser; Barbero, Mercedes; Stegen, Susana; Queirolo, Fabrizio; Díaz-Palma, Paula

    2013-01-01

    This study reports data on arsenic speciation in two green algae species (Cladophora sp. and Chara sp.) and in five aquatic plants (Azolla sp., Myriophyllum aquaticum, Phylloscirpus cf. desserticola, Potamogeton pectinatus, Ruppia filifolia and Zannichellia palustris) from the Loa River Basin in the Atacama Desert (northern Chile). Arsenic content was measured by Mass spectrometry coupled with Inductively Coupled Plasma (ICP-MS), after acidic digestion. Liquid chromatography coupled to ICP-MS was used for arsenic speciation, using both anionic and cationic chromatographic exchange systems. Inorganic arsenic compounds were the main arsenic species measured in all samples. The main arsenic species in the extracts of freshwater algae and plants were arsenite and arsenate, whereas glycerol-arsenosugar (gly-sug), dimethylarsinic acid (DMA) and methylarsonic acid (MA) were present only as minor constituents. Of the samples studied, algae species accumulated more arsenic than aquatic plants. Total arsenic content ranged from 182 to 11100 and from 20 to 248 mg As kg(-1) (d.w.) in algae and freshwater plants, respectively. In comparison with As concentration in water samples, there was hyper-accumulation (>0.1% d.w.) in Cladophora sp. PMID:22981629

  15. Biogas production experimental research using algae.

    PubMed

    Baltrėnas, Pranas; Misevičius, Antonas

    2015-01-01

    The current study is on the the use of macro-algae as feedstock for biogas production. Three types of macro-algae, Cladophora glomerata (CG), Chara fragilis (CF), and Spirogyra neglecta (SN), were chosen for this research. The experimental studies on biogas production were carried out with these algae in a batch bioreactor. In the bioreactor was maintained 35 ± 1°C temperature. The results showed that the most appropriate macro-algae for biogas production are Spirogyra neglecta (SN) and Cladophora glomerata (CG). The average amount of biogas obtained from the processing of SN - 0.23 m(3)/m(3)d, CG - 0.20 m(3)/m(3)d, and CF - 0.12 m(3)/m(3)d. Considering the concentration of methane obtained during the processing of SN and CG, which after eight days and until the end of the experiment exceeded 60%, it can be claimed that biogas produced using these algae is valuable. When processing CF, the concentration of methane reached the level of 50% only by the final day of the experiment, which indicates that this alga is less suitable for biogas production. PMID:25859392

  16. Antioxidant Activity of Hawaiian Marine Algae

    PubMed Central

    Kelman, Dovi; Posner, Ellen Kromkowski; McDermid, Karla J.; Tabandera, Nicole K.; Wright, Patrick R.; Wright, Anthony D.

    2012-01-01

    Marine algae are known to contain a wide variety of bioactive compounds, many of which have commercial applications in pharmaceutical, medical, cosmetic, nutraceutical, food and agricultural industries. Natural antioxidants, found in many algae, are important bioactive compounds that play an important role against various diseases and ageing processes through protection of cells from oxidative damage. In this respect, relatively little is known about the bioactivity of Hawaiian algae that could be a potential natural source of such antioxidants. The total antioxidant activity of organic extracts of 37 algal samples, comprising of 30 species of Hawaiian algae from 27 different genera was determined. The activity was determined by employing the FRAP (Ferric Reducing Antioxidant Power) assays. Of the algae tested, the extract of Turbinaria ornata was found to be the most active. Bioassay-guided fractionation of this extract led to the isolation of a variety of different carotenoids as the active principles. The major bioactive antioxidant compound was identified as the carotenoid fucoxanthin. These results show, for the first time, that numerous Hawaiian algae exhibit significant antioxidant activity, a property that could lead to their application in one of many useful healthcare or related products as well as in chemoprevention of a variety of diseases including cancer. PMID:22412808

  17. 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

  18. Algae for controlled ecological life support system diet characterization of cyanobacteria 'spirulina' in batch cultures

    NASA Technical Reports Server (NTRS)

    Tadros, M. G.

    1990-01-01

    Spirulina sp. is a bioregenerative photosynthetic and edible alga for space craft crews in a Closed Ecological Life Support System (CLESS). It was characterized for growth rate and biomass yield in batch cultures, under various environmental conditions. The cell characteristics were identified for one strain of Spirulina: S. maxima. Fast growth rate and high yield were obtained. The partitioning of the assimulatory products (proteins, carbohydrates, lipids) were manipulated by varying the environmental conditions. Experiments with Spirulina demonstrated that under stress conditions carbohydrate increased at the expense of protein. In other experiments, where the growth media were sufficient in nutrients and incubated under optimum growth conditions, the total proteins were increased up to almost 70 percent of the organic weight. In other words, the nutritional quality of the alga could be manipulated by growth conditions. These results support the feasibility of considering Spirulina as a subsystem in CELSS because of the ease with which its nutrient content can be manipulated.

  19. 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.

  20. The Path of Carbon in Photosynthesis XIII. pH Effects in C{sup 14}O{sub 2} Fixation by Scenedesmus

    DOE R&D Accomplishments Database

    Ouellet, C.; Benson, A. A.

    1951-10-23

    The rates of photosynthesis and dark fixation of C{sup 14}O{sub 2} in Scenedesmus have been compared in dilute phosphate buffers of 1.6 to 11.4 pH; determination of C{sup 14} incorporation into the various products shows enhancement of uptake in an acid medium into sucrose, polysaccharides, alanine and serine, in an alkaline medium into malic asparctic acids. kinetic experiments at extreme pH values suggest that several paths are available for CO{sub 2} assimilation. A tentative correlation of the results with the pH optima of some enzymes and resultant effects upon concentrations of intermediates is presented.

  1. Dynamic photoinhibition exhibited by red coralline algae in the red sea

    PubMed Central

    2014-01-01

    Background Red coralline algae are critical components of tropical reef systems, and their success and development is, at least in part, dependent on photosynthesis. However, natural variability in the photosynthetic characteristics of red coralline algae is poorly understood. This study investigated diurnal variability in encrusting Porolithon sp. and free-living Lithophyllum kotschyanum. Measured parameters included: photosynthetic characteristics, pigment composition, thallus reflectance and intracellular concentrations of dimethylsulphoniopropionate (DMSP), an algal antioxidant that is derived from methionine, an indirect product of photosynthesis. L. kotschyanum thalli were characterised by a bleached topside and a pigmented underside. Results Minimum saturation intensity and intracellular DMSP concentrations in Porolithon sp. were characterised by significant diurnal patterns in response to the high-light regime. A smaller diurnal pattern in minimum saturation intensity in the topside of L. kotschyanum was also evident. The overall reflectance of the topside of L. kotschyanum also exhibited a diurnal pattern, becoming increasingly reflective with increasing ambient irradiance. The underside of L. kotschyanum, which is shaded from ambient light exposure, exhibited a much smaller diurnal variability. Conclusions This study highlights a number of dynamic photoinhibition strategies adopted by coralline algae, enabling them to tolerate, rather than be inhibited by, the naturally high irradiance of tropical reef systems; a factor that may become more important in the future under global change projections. In this context, this research has significant implications for tropical reef management planning and conservation monitoring, which, if natural variability is not taken into account, may become flawed. The information provided by this research may be used to inform future investigations into the contribution of coralline algae to reef accretion, ecosystem

  2. Biotransformation of benzo[a]pyrene and other polycyclic aromatic hydrocarbons and heterocyclic analogs by several green algae and other algal species under gold and white light.

    PubMed

    Warshawsky, D; Cody, T; Radike, M; Reilman, R; Schumann, B; LaDow, K; Schneider, J

    1995-07-14

    This laboratory has shown that the metabolism of benzo[a]pyrene (BaP), a carcinogenic polycyclic aromatic hydrocarbon (PAH), by a freshwater green alga, Selenastrum capricornutum, under gold light proceeds through a dioxygenase pathway with subsequent conjugation and excretion. This study was undertaken to determine: (1) the effects of different light sources on the enzymatic or photochemical processes involved in the biotransformation of BaP over a dose range of 5-1200 mg/l; (2) the phototoxicity of carcinogenic PAHs and mutagenic quinones to a green alga; (3) the ability of other algal systems to metabolize BaP. Cultures were exposed to different doses of BaP for 2 days at 23 degrees C under gold, white or UV-A fluorescent light on a diurnal cycle of 16 h light, 8 h dark. Under gold light, metabolites of BaP produced by Selenastrum capricornutum were the dihydrodiols of which the 11,12-dihydrodiol was the major metabolite. Under white light, at low doses, the major metabolite was the 9,10-dihydrodiol. With increasing dose, the ratio of dihydrodiols to quinones decreased to less than two. With increasing light energy output, from gold to white to UV-A in the PAH absorbing region, BaP quinone production increased. Of other carcinogenic PAHs studied, only 7H-dibenz[c,g]carbazole was as phototoxic as BaP while 7,12-dimethylbenz[a]anthracene, dibenz[a,j]acridine and non-carcinogenic PAHs, anthracene and pyrene, were not phototoxic. The 3,6-quinone of BaP was found to be highly phototoxic while quinones that included menadione, danthron, phenanthrene-quinone and hydroquinone were not. The data suggest that the phototoxicity of BaP is due to photochemical production of quinones; the 3,6-quinone of BaP is phototoxic and is probably the result of the production of short lived cyclic reactive intermediates by the interaction of light with the quinone. Lastly, only the green algae, Selenastrum capricornutum, Scenedesmus acutus and Ankistrodesmus braunii almost completely

  3. The effects of wavelength and wavelength mixing ratios on microalgae growth and nitrogen, phosphorus removal using Scenedesmus sp. for wastewater treatment.

    PubMed

    Kim, Tae-Hyeong; Lee, Yunhee; Han, Su-Hyun; Hwang, Sun-Jin

    2013-02-01

    In wastewater treatment using microalgae, the effects of wavelength and wavelength mixing ratio on microalgae growth and removal of nitrogen and phosphorus were evaluated using LEDs (white light, 670nm, 450nm, and 525nm). Microalgae production rates were enhanced by a maximum of 45% with 400-700nm white light compared to that of a single wavelength. The phosphorus removal rate was as high as 90% with blue light. When red light and blue light were mixed and supplied, the microalgae production rate was about 50% higher than the rate of the culture with white light. Nitrogen and phosphorus removal rates were as high as approximately 15mg/L/day at a wavelength mixing ratio of 7 (red light):3 (blue light) and 2.1mg/L/day at a wavelength mixing ratio of 5 (red light):5 (blue light). PMID:23306113

  4. Removal of K+, Na+, Ca2+, and Mg2+ from saline-alkaline water using the microalga Scenedesmus obliquus

    NASA Astrophysics Data System (ADS)

    Yao, Zongli; Ying, Chengqi; Lu, Jianxue; Lai, Qifang; Zhou, Kai; Wang, Hui; Chen, Ling

    2013-11-01

    The capability of Scenedesmus obliquus to remove cations (K+, Na+, Ca2+, Mg2+) from saline-alkaline water was investigated at different salinities (0, 5, 10, 15, 20, 25) and carbonate alkalinities (0, 5, 10, 15, 20, 25, 30, 35 mmol/L). K+, Na+, Ca2+, and Mg2+ in saline-alkaline water were efficiently removed by S. obliquus. The maximum removal of the cations (29.37 mg for K+, 185.85 mg for Na+, 23.07 mg for Ca2+, 66.14 mg for Mg2+) occurred at salinity 25. The maximum removal of K+ (2.28 mg), Na+ (6.62 mg), Ca2+ (1.01 mg), and Mg2+ (0.62 mg) occurred at carbonate alkalinities of 25 mmol/L for K+, 35 mmol/L for Na+, 20 mmol/L for Ca2+, and 25 mmol/L for Mg2+, respectively. Under a salinity stress, the concentration of Na+ in S. obliquus increased significantly, while that of K+ decreased significantly. The concentrations of Ca2+ and Mg2+ decreased as well. The ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ were significantly lower in all salinity treatments than those of the control. Under alkaline stress, the concentrations of Na+ and K+ in S. obliquus decreased significantly and the ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ were significantly higher in all treatments than in the control. Moreover, the concentrations of Ca2+ and Mg2+ in S. obliquus at alkalinities of 5-10 mmol/L were significantly higher than those of the other treatments. The removal of Na+ by S. obliquus mainly occurs through biosorption, and Mg2+ and Ca2+ were removed through both biosorption and bioaccumulation.

  5. PPR proteins of green algae

    PubMed Central

    Tourasse, Nicolas J; Choquet, Yves; Vallon, Olivier

    2013-01-01

    Using the repeat finding algorithm FT-Rep, we have identified 154 pentatricopeptide repeat (PPR) proteins in nine fully sequenced genomes from green algae (with a total of 1201 repeats) and grouped them in 47 orthologous groups. All data are available in a database, PPRdb, accessible online at http://giavap-genomes.ibpc.fr/ppr. Based on phylogenetic trees generated from the repeats, we propose evolutionary scenarios for PPR proteins. Two PPRs are clearly conserved in the entire green lineage: MRL1 is a stabilization factor for the rbcL mRNA, while HCF152 binds in plants to the psbH-petB intergenic region. MCA1 (the stabilization factor for petA) and PPR7 (a short PPR also acting on chloroplast mRNAs) are conserved across the entire Chlorophyta. The other PPRs are clade-specific, with evidence for gene losses, duplications, and horizontal transfer. In some PPR proteins, an additional domain found at the C terminus provides clues as to possible functions. PPR19 and PPR26 possess a methyltransferase_4 domain suggesting involvement in RNA guanosine methylation. PPR18 contains a C-terminal CBS domain, similar to the CBSPPR1 protein found in nucleoids. PPR16, PPR29, PPR37, and PPR38 harbor a SmR (MutS-related) domain similar to that found in land plants pTAC2, GUN1, and SVR7. The PPR-cyclins PPR3, PPR4, and PPR6, in addition, contain a cyclin domain C-terminal to their SmR domain. PPR31 is an unusual PPR-cyclin containing at its N terminus an OctotricoPeptide Repeat (OPR) and a RAP domain. We consider the possibility that PPR proteins with a SmR domain can introduce single-stranded nicks in the plastid chromosome. PMID:24021981

  6. Use of chlorophyll a fluorescence to detect the effect of microcystins on photosynthesis and photosystem II energy fluxes of green algae.

    PubMed

    Perron, Marie-Claude; Qiu, Baosheng; Boucher, Nathalie; Bellemare, François; Juneau, Philippe

    2012-04-01

    The phenomenon of cyanobacteria bloom occurs widely in lakes, reservoirs, ponds and slow flowing rivers. Those blooms can have important repercussions, at once on recreational and commercial activities but also on the health of animals and human beings. Indeed, many species are known to produce toxins which are released in water mainly at cellular death. The cyanotoxin most frequently encountered is the microcystin (MC), a hepatotoxin which counts more than 70 variants. The use of fast tests for the detection of this toxin is thus a necessity for the protection of the ecosystems and the human health. A promising method for their detection is a bioassay based on the chlorophyll a fluorescence of algae. Many studies have shown that algae are sensible to diverse pollutants, but were almost never used for cyanotoxins. Therefore, our goals were to evaluate the effect of microcystin on the fluorescence of different species of algae and how it can affect the flow of energy through photosystem II. To reach these objectives, we exposed four green algae (Scenedesmus obliquus CPCC5, Chlamydomonas reinhardtii CC125, Pseudokirchneriella subcapitata CPCC37 and Chlorella vulgaris CPCC111) to microcystin standards (variants MC-LF, LR, RR, YR) and to microcystin extracted from Microcystis aeruginosa (CPCC299), which is known to produce mainly MC-LR. Chlorophyll a fluorescence was measured by PEA (Plant Efficiency Analyzer) and LuminoTox. The results of our experiment showed that microcystins affect the photosynthetic efficiency and the flow of energy through photosystem II from 0.01 μg/mL, within only 15 min. From exposure to standard of microcystin, we showed that MC-LF was the most potent variant, followed by MC-YR, LR and RR. Moreover, green algae used in this study demonstrated different sensitivity to MCs, S. obliquus being the more sensitive. We finally demonstrated that LuminoTox was more sensitive to MCs than parameters measured with PEA, although the latter brings

  7. Are Algae Relevant to the Detritus-Based Food Web in Tank-Bromeliads?

    PubMed Central

    Brouard, Olivier; Le Jeune, Anne-Hélène; Leroy, Céline; Cereghino, Régis; Roux, Olivier; Pelozuelo, Laurent; Dejean, Alain; Corbara, Bruno; Carrias, Jean-François

    2011-01-01

    We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from ∼102 to 104 cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web. PMID:21625603

  8. Estimation of alga growth stage and lipid content growth rate

    NASA Technical Reports Server (NTRS)

    Embaye, Tsegereda N. (Inventor); Trent, Jonathan D. (Inventor)

    2012-01-01

    Method and system for estimating a growth stage of an alga in an ambient fluid. Measured light beam absorption or reflection values through or from the alga and through an ambient fluid, in each of two or more wavelength sub-ranges, are compared with reference light beam absorption values for corresponding wavelength sub-ranges for in each alga growth stage to determine (1) which alga growth stage, if any, is more likely and (2) whether estimated lipid content of the alga is increasing or has peaked. Alga growth is preferably terminated when lipid content has approximately reached a maximum value.

  9. Studies on marine algae for haemagglutinic activity.

    PubMed

    Alam, M T; Usmanghani, K

    1994-07-01

    Lectins (agglutinins) are important in medical and immunological applications. Phytohaemagglutinins have been found useful in blood banking. Keeping in view of these facts, the marine algae found at Karachi coastal region have been screened for agglutinic activity by using human erythrocytes of A, B, AB and 0 group. Altogether 53 algal samples were collected and subjected to extraction, fractionation serial dilution and titre determinations. The total marine algae screened for haemagglutinic activity were 44 out of these 14, 13 and 17 belonged to Chlorophyta, Phaeophyta, and Rhodophyta respectively. Among these three groups the Rhodophyta showed the highest number of lytic activity. The green marine alga Valoniopsis pachynema showed a titre value between 2(2) and 2(3), which is statistically significant. In case of brown marine algae Colpomenia sinuosa was found to be active (titre 2(3)), while Dictyota dichotoma, D. indica and Iyengaria stellata, furnished week titre value as 2(2). The red marine algae screened were 17, out of these 4 spp. showed significant activity (titre 2(3)), and these are Gelidium usmanghani, Gracilaria foliifera Hypnea pannosa and Hynea valentiae. While Scinaia fascicularis, Scinaia indica and Champia parvula were found to be weak in their onset on human erythrocytes. The results obtained were quite in agreement with those reported in the literature. PMID:16414751

  10. Controlled regular locomotion of algae cell microrobots.

    PubMed

    Xie, Shuangxi; Jiao, Niandong; Tung, Steve; Liu, Lianqing

    2016-06-01

    Algae cells can be considered as microrobots from the perspective of engineering. These organisms not only have a strong reproductive ability but can also sense the environment, harvest energy from the surroundings, and swim very efficiently, accommodating all these functions in a body of size on the order of dozens of micrometers. An interesting topic with respect to random swimming motions of algae cells in a liquid is how to precisely control them as microrobots such that they swim according to manually set routes. This study developed an ingenious method to steer swimming cells based on the phototaxis. The method used a varying light signal to direct the motion of the cells. The swimming trajectory, speed, and force of algae cells were analyzed in detail. Then the algae cell could be controlled to swim back and forth, and traverse a crossroad as a microrobot obeying specific traffic rules. Furthermore, their motions along arbitrarily set trajectories such as zigzag, and triangle were realized successfully under optical control. Robotize algae cells can be used to precisely transport and deliver cargo such as drug particles in microfluidic chip for biomedical treatment and pharmacodynamic analysis. The study findings are expected to bring significant breakthrough in biological drives and new biomedical applications. PMID:27206511

  11. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements. PMID:20547408

  12. Complete mitochondrial genome of a hydrocarbon-producing green alga Botryococcus braunii strain Showa.

    PubMed

    Zou, Jiajun; Bi, Guiqi

    2016-07-01

    Complete mitochondrial genome of Botryococcus braunii strain Showa was assembled and annotated. It contains 31 protein-coding genes, 23 tRNA genes and 3 rRNA (23S, 16S, 5S rRNA) genes. The 31 protein-coding genes include 5 atp genes, 3 cox genes, 9 nad genes, 12 ribosomal protein genes, cob and tatC genes. The presence of extra non-coding regions makes it currently the largest mitochondrial genome in Trebouxiophyceae. Phylogenetic analysis showed Botryococcus braunii strain Showa clustered into Trebouxiophyceae clade and had close genetic relationship with algae Coccomyxa sp. C-169. PMID:26119114

  13. Plasmids in Frankia sp.

    PubMed

    Normand, P; Simonet, P; Butour, J L; Rosenberg, C; Moiroud, A; Lalonde, M

    1983-07-01

    A method to achieve cell lysis and isolate Frankia sp. plasmid DNA was developed. A screening of Frankia sp. strains belonging to different host compatibility groups (Alnus sp., Elaeagnus sp., Ceanothus sp.) showed that, of 39 strains tested, 4 (strains Cp11, ARgN22d, ArI3, and EUN1f) possessed plasmids ranging in size from 7.1 to 32.2 kilobase pairs as estimated from agarose gel electrophoresis and electron microscopy. A total of 11 plasmids were detected. PMID:6863219

  14. Turning Algae into Energy in New Mexico

    SciTech Connect

    Sayre, Richard; Olivares, Jose; Lammers, Peter

    2013-07-29

    Los Alamos National Laboratory, as part of the New Mexico Consortium - comprised of New Mexico's major research universities, the Lab, and key industry partners - is conducting research into using algae as a feed stock for a renewable source of fuels, and other products. There are hundreds of thousands of different algae species on Earth. They account for approximately half of the net photosynthesis on the planet, yet they have not been used in any kind of a large scale by humanity, with just a few exceptions. And yet, the biomass is easy to transform into useful products, including fuels, and they contain many other natural products that have high value. In this video Los Alamos and New Mexico State University scientists outline the opportunities and challenges of using science to turn algae into energy.

  15. Turning Algae into Energy in New Mexico

    ScienceCinema

    Sayre, Richard; Olivares, Jose; Lammers, Peter

    2014-06-24

    Los Alamos National Laboratory, as part of the New Mexico Consortium - comprised of New Mexico's major research universities, the Lab, and key industry partners - is conducting research into using algae as a feed stock for a renewable source of fuels, and other products. There are hundreds of thousands of different algae species on Earth. They account for approximately half of the net photosynthesis on the planet, yet they have not been used in any kind of a large scale by humanity, with just a few exceptions. And yet, the biomass is easy to transform into useful products, including fuels, and they contain many other natural products that have high value. In this video Los Alamos and New Mexico State University scientists outline the opportunities and challenges of using science to turn algae into energy.

  16. Genome of the red alga Porphyridium purpureum.

    PubMed

    Bhattacharya, Debashish; Price, Dana C; Chan, Cheong Xin; Qiu, Huan; Rose, Nicholas; Ball, Steven; Weber, Andreas P M; Arias, Maria Cecilia; Henrissat, Bernard; Coutinho, Pedro M; Krishnan, Anagha; Zäuner, Simone; Morath, Shannon; Hilliou, Frédérique; Egizi, Andrea; Perrineau, Marie-Mathilde; Yoon, Hwan Su

    2013-01-01

    The limited knowledge we have about red algal genomes comes from the highly specialized extremophiles, Cyanidiophyceae. Here, we describe the first genome sequence from a mesophilic, unicellular red alga, Porphyridium purpureum. The 8,355 predicted genes in P. purpureum, hundreds of which are likely to be implicated in a history of horizontal gene transfer, reside in a genome of 19.7 Mbp with 235 spliceosomal introns. Analysis of light-harvesting complex proteins reveals a nuclear-encoded phycobiliprotein in the alga. We uncover a complex set of carbohydrate-active enzymes, identify the genes required for the methylerythritol phosphate pathway of isoprenoid biosynthesis, and find evidence of sexual reproduction. Analysis of the compact, function-rich genome of P. purpureum suggests that ancestral lineages of red algae acted as mediators of horizontal gene transfer between prokaryotes and photosynthetic eukaryotes, thereby significantly enriching genomes across the tree of photosynthetic life. PMID:23770768

  17. Algae control problems and practices workshop

    SciTech Connect

    Pryfogle, P.A.; Ghio, G.

    1996-09-01

    Western water resources are continuously facing increased demand from industry and the public. Consequently, many of these resources are required to perform multiple tasks as they cycle through the ecosystem. Many plants and animals depend upon these resources for growth. Algae are one group of plants associated with nutrient and energy cycles in many aquatic ecosystems. Although most freshwater algae are microscopic in size, they are capable of dominating and proliferating to the extent that the value of the water resource for both industrial and domestic needs is compromised. There is a great diversity of aquatic environments and systems in which algae may be found, and there are many varieties of treatment and control techniques available to reduce the impacts of excessive growth. This workshop was organized to exchange information about these control problems and practices.

  18. Study of metal bioaccumulation by nuclear microprobe analysis of algae fossils and living algae cells

    NASA Astrophysics Data System (ADS)

    Guo, P.; Wang, J.; Li, X.; Zhu, J.; Reinert, T.; Heitmann, J.; Spemann, D.; Vogt, J.; Flagmeyer, R.-H.; Butz, T.

    2000-03-01

    Microscopic ion-beam analysis of palaeo-algae fossils and living green algae cells have been performed to study the metal bioaccumulation processes. The algae fossils, both single cellular and multicellular, are from the late Neoproterozonic (570 million years ago) ocean and perfectly preserved within a phosphorite formation. The biosorption of the rare earth element ions Nd 3+ by the green algae species euglena gracilis was investigated with a comparison between the normal cells and immobilized ones. The new Leipzig Nanoprobe, LIPSION, was used to produce a proton beam with 2 μm size and 0.5 nA beam current for this study. PIXE and RBS techniques were used for analysis and imaging. The observation of small metal rich spores ( <10 μm) surrounding both of the fossils and the living cells proved the existence of some specific receptor sites which bind metal carrier ligands at the microbic surface. The bioaccumulation efficiency of neodymium by the algae cells was 10 times higher for immobilized algae cells. It confirms the fact that the algae immobilization is an useful technique to improve its metal bioaccumulation.

  19. Anti-glycation properties of the aqueous extract solutions of dried algae products and effect of lactic acid fermentation on the properties.

    PubMed

    Kuda, Takashi; Eda, Mika; Kataoka, Manami; Nemoto, Maki; Kawahara, Miho; Oshio, Satoshi; Takahashi, Hajime; Kimura, Bon

    2016-02-01

    The antioxidant and anti-glycation properties in aqueous extract solutions (AESs) of 11 dried algae products were investigated. AESs of brown algae Ecklonia kurome (kurome) and Ecklonia stolonifera (tsuruarame) showed a strong DPPH radical-scavenging capacity and Fe-reducing power with high total phenolic compound content. On the other hand, superoxide anion radical-scavenging capacities of Porphyra sp. (iwanori, red alga), sporophyll of Undaria pinnatifida (mekabu, brown alga), and Gelidiaceae sp. (tengusa, red alga) were also high. Anti-glycation activities in BSA-fructose and BSA-methylglyoxal glycation were also high in kurome, while iwanori showed high activity. Results of the BSA-fructose model agreed with those of superoxide anion radical-scavenging. On the other hand, those of the BSA-methylglyoxal model agreed with those of the phenolic content, DPPH radical-scavenging capacity, and Fe-reducing power. Anti-glycation activities of iwanori, U. pinnatifida (wakame), and mekabu in the BSA-fructose model were clearly increased by fermentation with Lactobacillus plantarum AN6. PMID:26304454

  20. Harvesting of algae by froth flotation.

    PubMed

    LEVIN, G V; CLENDENNING, J R; GIBOR, A; BOGAR, F D

    1962-03-01

    A highly efficient froth flotation procedure has been developed for harvesting algae from dilute suspensions. The method does not depend upon the addition of flotants. Harvesting is carried out in a long column containing the feed solution which is aerated from below. A stable column of foam is produced and harvested from a side arm near the top of the column. The cell concentration of the harvest is a function of pH, aeration rate, aerator porosity, feed concentration, and height of foam in the harvesting column. The economic aspects of this process seem favorable for mass harvesting of algae for food or other purposes. PMID:14464557

  1. Use of Brown Algae to Demonstrate Natural Products Techniques.

    ERIC Educational Resources Information Center

    Porter, Lee A.

    1985-01-01

    Background information is provided on the natural products found in marine organisms in general and the brown algae in particular. Also provided are the procedures needed to isolate D-mannitol (a primary metabolite) and cholesterol from brown algae. (JN)

  2. Photodegradation of Norfloxacin in aqueous solution containing algae.

    PubMed

    Zhang, Junwei; Fu, Dafang; Wu, Jilong

    2012-01-01

    Photodegradation of Norfloxacin in aqueous solution containing algae under a medium pressure mercury lamp (15 W, lambda(max) = 365 nm) was investigated. Results indicated that the photodegradation of Norfloxacin could be induced by the algae in the heterogeneous algae-water systems. The photodegradation rate of Norfloxacin increased with increasing algae concentration, and was greatly influenced by the temperature and pH of solution. Meanwhile, the cooperation action of algae and Fe(III), and the ultrasound were beneficial to photodegradation of Norfloxacin. The degradation kinetics of Norfloxacin was found to follow the pseudo zero-order reaction in the suspension of algae. In addition, we discussed the photodegradation mechanism of Norfloxacin in the suspension of algae. This work will be helpful for understanding the photochemical degradation of antibiotics in aqueous environment in the presence of algae, for providing a new method to deal with antibiotics pollution. PMID:22894111

  3. An Overview of Algae Biofuel Production and Potential Environmental Impact

    EPA Science Inventory

    Algae are among the most potentially significant sources of sustainable biofuels in the future of renewable energy. A feedstock with virtually unlimited applicability, algae can metabolize various waste streams (e.g., municipal wastewater, carbon dioxide from industrial flue gas)...

  4. [Accumulation of polycyclic arenes in Baltic Sea algae].

    PubMed

    Veldre, I A; Itra, A R; Paal'me, L P; Kukk, Kh A

    1985-01-01

    The paper presents data on the level of benzo(a)pyrene (BP) and some other polycyclic arenes in alga and phanerogam specimens from different gulfs of the Baltic Sea. Algae were shown to absorb BP from sea water. The mean concentration of BP in sea water was under 0.004 microgram/1, while in algae it ranged 0.1-21.2 micrograms/kg dry weight. Algae accumulate BP to a higher degree than phanerogams. The highest concentrations of BP were found in algae Enteromorpha while the lowest ones in Furcellaria. In annual green algae, BP level was higher in autumn, i. e. at the end of vegetation period, than in spring. Brown algae Fucus vesiculosus is recommended for monitoring polycyclic arene pollution in the area from Vormsi Island to Käsmu and green algae Cladophora or Enteromorpha in the eastern part of the Finnish Gulf. PMID:4060672

  5. ALGAE BLOOMS AND PHOSPHORUS LOADING IN LAKE LOWELL, IDAHO

    EPA Science Inventory

    Algae blooms limit recreational use of Lake Lowell, ID (17050114) by reducing water clarity and esthetic qualities. Under bloom conditions, algae have a negative impact on the reservoir fishery because of periodic oxygen depletion associated with respiration and decomposition. ...

  6. WASP7 BENTHIC ALGAE - MODEL THEORY AND USER'S GUIDE

    EPA Science Inventory

    The standard WASP7 eutrophication module includes nitrogen and phosphorus cycling, dissolved oxygen-organic matter interactions, and phytoplankton kinetics. In many shallow streams and rivers, however, the attached algae (benthic algae, or periphyton, attached to submerged substr...

  7. Hydrogen production from salt water by Marine blue green algae and solar radiation

    NASA Technical Reports Server (NTRS)

    Mitsui, A.; Rosner, D.; Kumazawa, S.; Barciela, S.; Phlips, E.

    1985-01-01

    Two marine bluegreen algae, Oscillatoria sp. Miami BG 7 and Synechococcus sp Miami 041511 have been selected as the result of over 10 years continuous and intensive effort of isolation, growth examination, and the screening of hydrogen photoproduction capability in this laboratory. Both strains photoproduced hydrogen for several days at high rates and a quantity of hydrogen was accumulated in a closed vessel. Overall hydrogen donor substance of the hydrogen photoproduction was found to be salt water. Using strain Miami BG 7, a two step method of hydrogen photoproduction from salt water was successfully developed and this was recycled several times over a one month period using both free cells and immobilized cells in both indoor and outdoor under natural sunlight. According to these experiments, a prototype floating hydrogen production system was designed for further development of the biosolar hydrogen production system.

  8. 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.

  9. Heavy metal bioaccumulation in sediment, common reed, algae, and blood worm from the Shoor river, Iran.

    PubMed

    Hamidian, Amir Hossein; Zareh, Maryam; Poorbagher, Hadi; Vaziri, Leila; Ashrafi, Sohrab

    2016-03-01

    Concentrations of 11 metals (cadmium, zinc, copper (Cu), vanadium (V), lead, magnesium (Mg), manganese, aluminum, iron (Fe), chromium (Cr), and nickel), and one metalloid (arsenic (As)) were measured in sediment, common reed (Phragmites australis), algae (Spirogyra sp.), and blood worm (Chironomus sp.) tissues of samples collected from the Shoor river. Samples were dried, acid digested, and the concentrations of metals were measured using inductively coupled plasma-optical emission spectrometer. A higher concentration of heavy metals was accumulated in Spirogyra and Chironomids than sediment and common reed. The highest rate of accumulation was found for Mg, V, Fe, As, Cu, and Cr. Spirogyra and Chironomids are capable of accumulating and thereby removing metals from polluted water bodies and are suitable for biomonitoring purposes. PMID:24105065

  10. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  11. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  12. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  13. How to Identify and Control Water Weeds and Algae.

    ERIC Educational Resources Information Center

    Applied Biochemists, Inc., Mequon, WI.

    Included in this guide to water management are general descriptions of algae, toxic algae, weed problems in lakes, ponds, and canals, and general discussions of mechanical, biological and chemical control methods. In addition, pictures, descriptions, and recommended control methods are given for algae, 6 types of floating weeds, 18 types of…

  14. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  15. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the...

  16. Fucoidans — sulfated polysaccharides of brown algae

    NASA Astrophysics Data System (ADS)

    Usov, Anatolii I.; Bilan, M. I.

    2009-08-01

    The methods of isolation of fucoidans and determination of their chemical structures are reviewed. The fucoidans represent sulfated polysaccharides of brown algae, the composition of which varies from simple fucan sulfates to complex heteropolysaccharides. The currently known structures of such biopolymers are presented. A variety of the biological activities of fucoidans is briefly summarised.

  17. Potential of mass algae production in Kuwait

    SciTech Connect

    Prokop, A.; Fekri, M.

    1984-11-01

    The rationale for efficient light absorption by algae at a production unit is given and design details of an intensive thin-layer technology outdoor (2.11m/sup 2/) unit are presented. Data on productivity under extreme conditions were collected. Maximum productivity data are close to those reported in the literature for similar geographic areas.

  18. Laser-fluorescence measurement of marine algae

    NASA Technical Reports Server (NTRS)

    Browell, E. V.

    1980-01-01

    Progress in remote sensing of algae by laser-induced fluorescence is subject of comprehensive report. Existing single-wavelength and four-wavelength systems are reviewed, and new expression for power received by airborne sensor is derived. Result differs by as much as factor of 10 from those previously reported. Detailed error analysis evluates factors affecting accuracy of laser-fluorosensor systems.

  19. OPTIMAL COST CONTROL STRATEGIES FOR ATTACHED ALGAE

    EPA Science Inventory

    This paper presents a cost-benefit analysis for alternative programs intended for the control of the nuisance growth of an attached alga (Cladophora). Such analyses require that changes in water quality be quantitatively related to the cost of implementation for specific manageme...

  20. Spirulina: The Alga That Can End Malnutrition.

    ERIC Educational Resources Information Center

    Fox, Ripley D.

    1985-01-01

    One approach to eliminating malnutrition worldwide is to grow spirulina in recycled village wastes. Spirulina is a blue-green alga and a natural concentrated food. Spirulina can give poor villages a nutritional food supplement they can grow themselves and can reduce infectious disease at the same time. (Author/RM)

  1. Effect of Relative Humidity on the Survival of Airborne Unicellular Algae

    PubMed Central

    Ehresmann, Douglas W.; Hatch, Melvin T.

    1975-01-01

    A method is described which is suitable for assessing the effects of relative humidity (RH) on the viability of two unicellular algae in experimental aerosols. Viable cells of Nannochloris atomus collected from the airborne state were detected by plating onto agar surfaces of an appropriate growth medium, whereas viable airborne cells of Synechococcus sp., because of unreliable growth on solid media, were determined by a liquid assay system. The assays were performed at intervals during short-term and prolonged storage of algal aerosols in chambers preconditioned to a selected RH and temperature. Both species showed the greatest loss in viability during the first minute after atomization, and the extent of this inactivation, as a function of RH, reflected the subsequent long-term survival. The airborne eukaryotic alga was unable to survive at an RH below 91%, whereas the airborne prokaryotic alga was comparatively stable over a wide humidity range. Initial inactivation was least and long-term survival best, for both species, at 94% RH. Images PMID:1115506

  2. First freshwater coralline alga and the role of local features in a major biome transition

    PubMed Central

    Žuljević, A.; Kaleb, S.; Peña, V.; Despalatović, M.; Cvitković, I.; De Clerck, O.; Le Gall, L.; Falace, A.; Vita, F.; Braga, Juan C.; Antolić, B.

    2016-01-01

    Coralline red algae are significant components of sea bottom and up to now considered as exclusively marine species. Here we present the first coralline alga from a freshwater environment, found in the Cetina River (Adriatic Sea watershed). The alga is fully adapted to freshwater, as attested by reproductive structures, sporelings, and an inability to survive brackish conditions. Morphological and molecular phylogenetic analyses reveal the species belongs to Pneophyllum and is described as P. cetinaensis sp. nov. The marine-freshwater transition most probably occurred during the last glaciation. The brackish-water ancestor was preadapted to osmotic stress and rapid changes in water salinity and temperature. The particular characteristics of the karst Cetina River, such as hard water enriched with dissolved calcium carbonate and a pH similar to the marine environment, favoured colonization of the river by a marine species. The upstream advance and dispersal is facilitated by exceptionally pronounced zoochory by freshwater gastropods. Pneophyllum cetinaensis defies the paradigm of Corallinales as an exclusively marine group. PMID:26791421

  3. First freshwater coralline alga and the role of local features in a major biome transition

    NASA Astrophysics Data System (ADS)

    Žuljević, A.; Kaleb, S.; Peña, V.; Despalatović, M.; Cvitković, I.; de Clerck, O.; Le Gall, L.; Falace, A.; Vita, F.; Braga, Juan C.; Antolić, B.

    2016-01-01

    Coralline red algae are significant components of sea bottom and up to now considered as exclusively marine species. Here we present the first coralline alga from a freshwater environment, found in the Cetina River (Adriatic Sea watershed). The alga is fully adapted to freshwater, as attested by reproductive structures, sporelings, and an inability to survive brackish conditions. Morphological and molecular phylogenetic analyses reveal the species belongs to Pneophyllum and is described as P. cetinaensis sp. nov. The marine-freshwater transition most probably occurred during the last glaciation. The brackish-water ancestor was preadapted to osmotic stress and rapid changes in water salinity and temperature. The particular characteristics of the karst Cetina River, such as hard water enriched with dissolved calcium carbonate and a pH similar to the marine environment, favoured colonization of the river by a marine species. The upstream advance and dispersal is facilitated by exceptionally pronounced zoochory by freshwater gastropods. Pneophyllum cetinaensis defies the paradigm of Corallinales as an exclusively marine group.

  4. First freshwater coralline alga and the role of local features in a major biome transition.

    PubMed

    Žuljević, A; Kaleb, S; Peña, V; Despalatović, M; Cvitković, I; De Clerck, O; Le Gall, L; Falace, A; Vita, F; Braga, Juan C; Antolić, B

    2016-01-01

    Coralline red algae are significant components of sea bottom and up to now considered as exclusively marine species. Here we present the first coralline alga from a freshwater environment, found in the Cetina River (Adriatic Sea watershed). The alga is fully adapted to freshwater, as attested by reproductive structures, sporelings, and an inability to survive brackish conditions. Morphological and molecular phylogenetic analyses reveal the species belongs to Pneophyllum and is described as P. cetinaensis sp. nov. The marine-freshwater transition most probably occurred during the last glaciation. The brackish-water ancestor was preadapted to osmotic stress and rapid changes in water salinity and temperature. The particular characteristics of the karst Cetina River, such as hard water enriched with dissolved calcium carbonate and a pH similar to the marine environment, favoured colonization of the river by a marine species. The upstream advance and dispersal is facilitated by exceptionally pronounced zoochory by freshwater gastropods. Pneophyllum cetinaensis defies the paradigm of Corallinales as an exclusively marine group. PMID:26791421

  5. 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

  6. Validation of housekeeping genes for gene expression studies in an ice alga Chlamydomonas during freezing acclimation.

    PubMed

    Liu, Chenlin; Wu, Guangting; Huang, Xiaohang; Liu, Shenghao; Cong, Bailin

    2012-05-01

    Antarctic ice alga Chlamydomonas sp. ICE-L can endure extreme low temperature and high salinity stress under freezing conditions. To elucidate the molecular acclimation mechanisms using gene expression analysis, the expression stabilities of ten housekeeping genes of Chlamydomonas sp. ICE-L during freezing stress were analyzed. Some discrepancies were detected in the ranking of the candidate reference genes between geNorm and NormFinder programs, but there was substantial agreement between the groups of genes with the most and the least stable expression. RPL19 was ranked as the best candidate reference genes. Pairwise variation (V) analysis indicated the combination of two reference genes was sufficient for qRT-PCR data normalization under the experimental conditions. Considering the co-regulation between RPL19 and RPL32 (the most stable gene pairs given by geNorm program), we propose that the mean data rendered by RPL19 and GAPDH (the most stable gene pairs given by NormFinder program) be used to normalize gene expression values in Chlamydomonas sp. ICE-L more accurately. The example of FAD3 gene expression calculation demonstrated the importance of selecting an appropriate category and number of reference genes to achieve an accurate and reliable normalization of gene expression during freeze acclimation in Chlamydomonas sp. ICE-L. PMID:22527038

  7. Kinetics of nutrient removal and expression of extracellular polymeric substances of the microalgae, Chlorella sp. and Micractinium sp., in wastewater treatment.

    PubMed

    Wang, Meng; Kuo-Dahab, Wenye Camilla; Dolan, Sona; Park, Chul

    2014-02-01

    Two species of green algae, Chlorella sp. and Micractinium sp., were cultivated in primary effluent wastewater and high-strength wastewater (a mixture of anaerobic digestion centrate and primary effluent) to study nutrient removal and EPS (extracellular polymeric substances) expression during their growth. The high N concentration and P-limited condition in the mixed wastewater (total N=197 mg/L; N/P mass ratio=56) led to about 3 times greater specific N removal rate than the primary effluent set, indicating that algal cells growing in N-rich wastewater had N over-uptake. Both Chlorella and Micractinium grown in the high-strength wastewater also produced larger amounts of protein EPS, possibly accounting for higher N uptake in those cultivation sets. These results suggest that different types of wastewater could cause different nutrient removal kinetics and EPS expression by algae, which may subsequently influence harvesting and anaerobic digestion of their biomass. PMID:24384320

  8. 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

  9. Integrated 'Omics', Targeted Metabolite and Single-cell Analyses of Arctic Snow Algae Functionality and Adaptability.

    PubMed

    Lutz, Stefanie; Anesio, Alexandre M; Field, Katie; Benning, Liane G

    2015-01-01

    Snow algae are poly-extremophilic microalgae and important primary colonizers and producers on glaciers and snow fields. Depending on their pigmentation they cause green or red mass blooms during the melt season. This decreases surface albedo and thus further enhances snow and ice melting. Although the phenomenon of snow algal blooms has been known for a long time, large aspects of their physiology and ecology sill remain cryptic. This study provides the first in-depth and multi-omics investigation of two very striking adjacent green and red snow fields on a glacier in Svalbard. We have assessed the algal community composition of green and red snow including their associated microbiota, i.e., bacteria and archaea, their metabolic profiles (targeted and non-targeted metabolites) on the bulk and single-cell level, and assessed the feedbacks between the algae and their physico-chemical environment including liquid water content, pH, albedo, and nutrient availability. We demonstrate that green and red snow clearly vary in their physico-chemical environment, their microbial community composition and their metabolic profiles. For the algae this likely reflects both different stages of their life cycles and their adaptation strategies. Green snow represents a wet, carbon and nutrient rich environment and is dominated by the algae Microglena sp. with a metabolic profile that is characterized by key metabolites involved in growth and proliferation. In contrast, the dry and nutrient poor red snow habitat is colonized by various Chloromonas species with a high abundance of storage and reserve metabolites likely to face upcoming severe conditions. Combining a multitude of techniques we demonstrate the power of such complementary approaches in elucidating the function and ecology of extremophiles such as green and red snow algal blooms, which play crucial roles in glacial ecosystems. PMID:26635781

  10. Capillary Electrophoresis Single-Strand Conformational Polymorphisms as a Method to Differentiate Algal Species.

    PubMed

    Jernigan, Alice; Hestekin, Christa

    2015-01-01

    Capillary electrophoresis single-strand conformational polymorphism (CE-SSCP) was explored as a fast and inexpensive method to differentiate both prokaryotic (blue-green) and eukaryotic (green and brown) algae. A selection of two blue-green algae (Nostoc muscorum and Anabaena inaequalis), five green algae (Chlorella vulgaris, Oedogonium foveolatum, Mougeotia sp., Scenedesmus quadricauda, and Ulothrix fimbriata), and one brown algae (Ectocarpus sp.) were examined and CE-SSCP electropherogram "fingerprints" were compared to each other for two variable regions of either the 16S or 18S rDNA gene. The electropherogram patterns were remarkably stable and consistent for each particular species. The patterns were unique to each species, although some common features were observed between the different types of algae. CE-SSCP could be a useful method for monitoring changes in an algae species over time as potential shifts in species occurred. PMID:26101693

  11. Capillary Electrophoresis Single-Strand Conformational Polymorphisms as a Method to Differentiate Algal Species

    PubMed Central

    Jernigan, Alice; Hestekin, Christa

    2015-01-01

    Capillary electrophoresis single-strand conformational polymorphism (CE-SSCP) was explored as a fast and inexpensive method to differentiate both prokaryotic (blue-green) and eukaryotic (green and brown) algae. A selection of two blue-green algae (Nostoc muscorum and Anabaena inaequalis), five green algae (Chlorella vulgaris, Oedogonium foveolatum, Mougeotia sp., Scenedesmus quadricauda, and Ulothrix fimbriata), and one brown algae (Ectocarpus sp.) were examined and CE-SSCP electropherogram “fingerprints” were compared to each other for two variable regions of either the 16S or 18S rDNA gene. The electropherogram patterns were remarkably stable and consistent for each particular species. The patterns were unique to each species, although some common features were observed between the different types of algae. CE-SSCP could be a useful method for monitoring changes in an algae species over time as potential shifts in species occurred. PMID:26101693

  12. Blue-Green Algae Inhibit the Development of Atherosclerotic Lesions in Apolipoprotein E Knockout Mice.

    PubMed

    Ku, Chai Siah; Kim, Bohkyung; Pham, Tho X; Yang, Yue; Wegner, Casey J; Park, Young-Ki; Balunas, Marcy; Lee, Ji-Young

    2015-12-01

    Hyperlipidemia and inflammation contribute to the development of atherosclerotic lesions. Our objective was to determine antiatherogenic effect of edible blue-green algae (BGA) species, that is, Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP), in apolipoprotein E knockout (ApoE(-/-)) mice, a well-established mouse model of atherosclerosis. Male ApoE(-/-) mice were fed a high-fat/high-cholesterol (HF/HC, 15% fat and 0.2% cholesterol by wt) control diet or a HF/HC diet supplemented with 5% (w/w) of NO or SP powder for 12 weeks. Plasma total cholesterol (TC) and triglycerides (TG) were measured, and livers were analyzed for histology and gene expression. Morphometric analysis for lesions and immunohistochemical analysis for CD68 were conducted in the aorta and the aortic root. NO supplementation significantly decreased plasma TC and TG, and liver TC, compared to control and SP groups. In the livers of NO-fed mice, less lipid droplets were present with a concomitant decrease in fatty acid synthase protein levels than the other groups. There was a significant increase in hepatic low-density lipoprotein receptor protein levels in SP-supplemented mice than in control and NO groups. Quantification of aortic lesions by en face analysis demonstrated that both NO and SP decreased aortic lesion development to a similar degree compared with control. While lesions in the aortic root were not significantly different between groups, the CD68-stained area in the aortic root was significantly lowered in BGA-fed mice than controls. In conclusion, both NO and SP supplementation decreased the development of atherosclerotic lesions, suggesting that they may be used as a natural product for atheroprotection. PMID:26566121

  13. The synergistic effects for the co-cultivation of oleaginous yeast-Rhodotorula glutinis and microalgae-Scenedesmus obliquus on the biomass and total lipids accumulation.

    PubMed

    Yen, Hong-Wei; Chen, Pin-Wen; Chen, Li-Juan

    2015-05-01

    In this co-culture of oleaginous yeast-Rhodotorula glutinis and microalgae-Scenedesmus obliquus, microalgae potentially acts as an oxygen generator for the growth of aerobic yeast while the yeast mutually provides CO2 to the microalgae as both carry out the production of lipids. To explore the synergistic effects of co-cultivation on the cells growth and total lipids accumulation, several co-culture process parameters including the carbon source concentration, temperature and dissolved oxygen level would be firstly investigated in the flask trials. The results of co-culture in a 5L photobioreactor revealed that about 40-50% of biomass increased and 60-70% of total lipid increased was observed as compared to the single culture batches. Besides the synergistic effects of gas utilization, the providing of trace elements to each other after the natural cells lysis was believed to be another benefit to the growth of the overall co-culture system. PMID:25311189

  14. A one-stage cultivation process for lipid- and carbohydrate-rich biomass of Scenedesmus obtusiusculus based on artificial and natural water sources.

    PubMed

    Schulze, Christian; Reinhardt, Jakob; Wurster, Martina; Ortiz-Tena, José Guillermo; Sieber, Volker; Mundt, Sabine

    2016-10-01

    A one-stage cultivation process of the microalgae Scenedesmus obtusiusculus with medium based on natural water sources was developed to enhance lipids and carbohydrates. A medium based on artificial sea water, Baltic Sea water and river water with optimized nutrient concentrations compared to the standard BG-11 for nitrate (-75%), phosphate and iron (-90%) was used for cultivation. Although nitrate exhaustion over cultivation resulted in nitrate limitation, growth of the microalgae was not reduced. The lipid content increased from 6.0% to 19.9%, an increase in oleic and stearic acid was observed. The unsaponifiable matter of the lipid fraction was reduced from 19.5% to 11.4%. The carbohydrate yield rose from 45% to 50% and the protein content decreased from 32.4% to 15.9%. Using natural water sources with optimized nutrient concentrations could open the opportunity to modulate biomass composition and to reduce the cultivation costs. PMID:27394996

  15. Chlorophyll-Protein Complexes of the Cyanophyte, Nostoc sp. 1

    PubMed Central

    Rusckowski, Mary; Zilinskas, Barbara A.

    1980-01-01

    Four chlorophyll-protein complexes have been resolved from the cyanophyte, Nostoc sp., by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis at 4 C. Complexes solubilized by SDS from Spinacia oleracea were run for comparison. As has been well documented, the P700-chlorophyll a-protein complex from the higher plant and blue-green algal samples are similar, and the light-harvesting pigment protein complex is present only in the former. Most noteworthy are two closely migrating chlorophyll proteins in Nostoc sp. which have approximately the same mobility as a single chlorophyll-protein band resolvable from spinach. The absorption maximum of the complex from spinach is at 667 nanometers, and those of the two complexes from Nostoc sp. are at 667 and 669 nanometers; the fluorescence emission maximum at −196 C is at 685 nanometers, and the 735 nanometer fluorescence peak, characteristic of the P700-chlorophyll a-protein complex, is absent. The apoproteins of these new complexes from Nostoc sp. and spinach are in the kilodalton range. It appears that at least one of these two chlorophyll-protein complexes from Nostoc sp. compares with those recently described by others from higher plants and green algae as likely photosystem II complexes, perhaps containing P680, although no photochemical data are yet available. Images PMID:16661198

  16. Structurally Distinct Cation Channelrhodopsins from Cryptophyte Algae.

    PubMed

    Govorunova, Elena G; Sineshchekov, Oleg A; Spudich, John L

    2016-06-01

    Microbial rhodopsins are remarkable for the diversity of their functional mechanisms based on the same protein scaffold. A class of rhodopsins from cryptophyte algae show close sequence homology with haloarchaeal rhodopsin proton pumps rather than with previously known channelrhodopsins from chlorophyte (green) algae. In particular, both aspartate residues that occupy the positions of the chromophore Schiff base proton acceptor and donor, a hallmark of rhodopsin proton pumps, are conserved in these cryptophyte proteins. We expressed the corresponding polynucleotides in human embryonic kidney (HEK293) cells and studied electrogenic properties of the encoded proteins with whole-cell patch-clamp recording. Despite their lack of residues characteristic of the chlorophyte cation channels, these proteins are cation-conducting channelrhodopsins that carry out light-gated passive transport of Na(+) and H(+). These findings show that channel function in rhodopsins has evolved via multiple routes. PMID:27233115

  17. Phycobilisomes in Blue-Green Algae

    PubMed Central

    Wildman, Ruth B.; Bowen, C. C.

    1974-01-01

    Fifteen species of freshwater blue-green algae, including unicellular, filamentous, and colonial forms, were subjected to a variety of fixatives, fixation conditions, and stains for comparison of the preservation of phycobilisomes. Absorption spectra of the corresponding in vivo and released photosynthetic pigments, in 10 of the species that were maintained in culture, demonstrated the presence of phycocyanin in all 10 species and phycoerythrin in only 2 of them. Spectroscope and electron microscope evidence was obtained for localization of phycobiliproteins in phycobilisomes of Nostoc muscorum. Phycobilisomes were observed in all species examined in situ, strenghening the hypothesis that phycobilisomes are common to all phycobiliprotein-containing photosynthetic blue-green algae. Images PMID:4204443

  18. Biofuels from algae: challenges and potential

    PubMed Central

    Hannon, Michael; Gimpel, Javier; Tran, Miller; Rasala, Beth; Mayfield, Stephen

    2011-01-01

    Algae biofuels may provide a viable alternative to fossil fuels; however, this technology must overcome a number of hurdles before it can compete in the fuel market and be broadly deployed. These challenges include strain identification and improvement, both in terms of oil productivity and crop protection, nutrient and resource allocation and use, and the production of co-products to improve the economics of the entire system. Although there is much excitement about the potential of algae biofuels, much work is still required in the field. In this article, we attempt to elucidate the major challenges to economic algal biofuels at scale, and improve the focus of the scientific community to address these challenges and move algal biofuels from promise to reality. PMID:21833344

  19. The GC-Rich Mitochondrial and Plastid Genomes of the Green Alga Coccomyxa Give Insight into the Evolution of Organelle DNA Nucleotide Landscape

    SciTech Connect

    Smith, David Roy; Burki, Fabien; Yamada, Takashi; Grimwood, Jane; Grigoriev, Igor V.; Van Etten, James L.; Keeling, Patrick J.

    2011-05-13

    Most of the available mitochondrial and plastid genome sequences are biased towards adenine and thymine (AT) over guanine and cytosine (GC). Examples of GC-rich organelle DNAs are limited to a small but eclectic list of species, including certain green algae. Here, to gain insight in the evolution of organelle nucleotide landscape, we present the GC-rich mitochondrial and plastid DNAs from the trebouxiophyte green alga Coccomyxa sp. C-169. We compare these sequences with other GC-rich organelle DNAs and argue that the forces biasing them towards G and C are nonadaptive and linked to the metabolic and/or life history features of this species. The Coccomyxa organelle genomes are also used for phylogenetic analyses, which highlight the complexities in trying to resolve the interrelationships among the core chlorophyte green algae, but ultimately favour a sister relationship between the Ulvophyceae and Chlorophyceae, with the Trebouxiophyceae branching at the base of the chlorophyte crown.

  20. Selenium Uptake and Volatilization by Marine Algae

    NASA Astrophysics Data System (ADS)

    Luxem, Katja E.; Vriens, Bas; Wagner, Bettina; Behra, Renata; Winkel, Lenny H. E.

    2015-04-01

    Selenium (Se) is an essential trace nutrient for humans. An estimated one half to one billion people worldwide suffer from Se deficiency, which is due to low concentrations and bioavailability of Se in soils where crops are grown. It has been hypothesized that more than half of the atmospheric Se deposition to soils is derived from the marine system, where microorganisms methylate and volatilize Se. Based on model results from the late 1980s, the atmospheric flux of these biogenic volatile Se compounds is around 9 Gt/year, with two thirds coming from the marine biosphere. Algae, fungi, and bacteria are known to methylate Se. Although algal Se uptake, metabolism, and methylation influence the speciation and bioavailability of Se in the oceans, these processes have not been quantified under environmentally relevant conditions and are likely to differ among organisms. Therefore, we are investigating the uptake and methylation of the two main inorganic Se species (selenate and selenite) by three globally relevant microalgae: Phaeocystis globosa, the coccolithophorid Emiliania huxleyi, and the diatom Thalassiosira oceanica. Selenium uptake and methylation were quantified in a batch experiment, where parallel gas-tight microcosms in a climate chamber were coupled to a gas-trapping system. For E. huxleyi, selenite uptake was strongly dependent on aqueous phosphate concentrations, which agrees with prior evidence that selenite uptake by phosphate transporters is a significant Se source for marine algae. Selenate uptake was much lower than selenite uptake. The most important volatile Se compounds produced were dimethyl selenide, dimethyl diselenide, and dimethyl selenyl sulfide. Production rates of volatile Se species were larger with increasing intracellular Se concentration and in the decline phase of the alga. Similar experiments are being carried out with P. globosa and T. oceanica. Our results indicate that marine algae are important for the global cycling of Se

  1. Algae-Derived Dietary Ingredients Nourish Animals

    NASA Technical Reports Server (NTRS)

    2015-01-01

    In the 1980s, Columbia, Maryland-based Martek Biosciences Corporation worked with Ames Research Center to pioneer the use of microalgae as a source of essential omega-3 fatty acids, work that led the company to develop its highly successful Formulaid product. Now the Nutritional Products Division of Royal DSM, the company also manufactures DHAgold, a nutritional supplement for pets, livestock and farm-raised fish that uses algae to deliver docosahexaenoic acid (DHA).

  2. Algae as Reservoirs for Coral Pathogens

    PubMed Central

    Sweet, Michael J.; Bythell, John C.; Nugues, Maggy M.

    2013-01-01

    Benthic algae are associated with coral death in the form of stress and disease. It's been proposed that they release exudates, which facilitate invasion of potentially pathogenic microbes at the coral-algal interface, resulting in coral disease. However, the original source of these pathogens remains unknown. This study examined the ability of benthic algae to act as reservoirs of coral pathogens by characterizing surface associated microbes associated with major Caribbean and Indo-Pacific algal species/types and by comparing them to potential pathogens of two dominant coral diseases: White Syndrome (WS) in the Indo-Pacific and Yellow Band Disease (YBD) in the Caribbean. Coral and algal sampling was conducted simultaneously at the same sites to avoid spatial effects. Potential pathogens were defined as those absent or rare in healthy corals, increasing in abundance in healthy tissues adjacent to a disease lesion, and dominant in disease lesions. Potentially pathogenic bacteria were detected in both WS and YBD and were also present within the majority of algal species/types (54 and 100% for WS and YBD respectively). Pathogenic ciliates were associated only with WS and not YBD lesions and these were also present in 36% of the Indo-Pacific algal species. Although potential pathogens were associated with many algal species, their presence was inconsistent among replicate algal samples and detection rates were relatively low, suggestive of low density and occurrence. At the community level, coral-associated microbes irrespective of the health of their host differed from algal-associated microbes, supporting that algae and corals have distinctive microbial communities associated with their tissue. We conclude that benthic algae are common reservoirs for a variety of different potential coral pathogens. However, algal-associated microbes alone are unlikely to cause coral death. Initial damage or stress to the coral via other competitive mechanisms is most likely a

  3. Prokaryotic algae associated with Australian proterozoic stromatolites.

    NASA Technical Reports Server (NTRS)

    Licari, G. R.; Cloud, P.

    1972-01-01

    The most favorable sites in which to study the associations between stromatolites and the algae responsible for them are places where a variety of stromatolites of possibly early diagenetic or primary silica occupy a layer of substantial thickness of little metamorphosed ancient sediments. One such place is in northwestern Queensland, Australia. Five cases of association between stromatolites and blue-green algal nannofossils were observed within a 100-m sequence of carbonate rocks in that area.

  4. Sequestration of CO2 by halotolerant algae

    PubMed Central

    2014-01-01

    The potential of halotolerant algae isolated from natural resources was used to study CO2 fixation and algal lipid production. Biological fixation of CO2 in photobioreactor in presence of salinity is exploited. The CO2 concentration 1060 ppm gave the highest biomass yield (700 mg dry wt/l), the highest total lipid content (10.33%) with 80% of CO2 removal. PMID:24847439

  5. Dermatitis from purified sea algae toxin (debromoaplysiatoxin).

    PubMed

    Solomon, A E; Stoughton, R B

    1978-09-01

    Cutaneous inflammation was induced by debromoaplysiatoxin, a purified toxin extracted from Lyngbya majuscula Gomont. This alga causes a seaweed dermatitis that occurs in persons who have swum off the coast of Oahu in Hawaii. By topical application, the toxin was found to produce an irritant pustular folliculitis in humans and to cause a severe cutaneous inflammatory reaction in the rabbit and in hairless mice. PMID:686747

  6. Environmental life cycle comparison of algae to other bioenergy feedstocks.

    PubMed

    Clarens, Andres F; Resurreccion, Eleazer P; White, Mark A; Colosi, Lisa M

    2010-03-01

    Algae are an attractive source of biomass energy since they do not compete with food crops and have higher energy yields per area than terrestrial crops. In spite of these advantages, algae cultivation has not yet been compared with conventional crops from a life cycle perspective. In this work, the impacts associated with algae production were determined using a stochastic life cycle model and compared with switchgrass, canola, and corn farming. The results indicate that these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location. Only in total land use and eutrophication potential do algae perform favorably. The large environmental footprint of algae cultivation is driven predominantly by upstream impacts, such as the demand for CO(2) and fertilizer. To reduce these impacts, flue gas and, to a greater extent, wastewater could be used to offset most of the environmental burdens associated with algae. To demonstrate the benefits of algae production coupled with wastewater treatment, the model was expanded to include three different municipal wastewater effluents as sources of nitrogen and phosphorus. Each provided a significant reduction in the burdens of algae cultivation, and the use of source-separated urine was found to make algae more environmentally beneficial than the terrestrial crops. PMID:20085253

  7. Electro-coagulation-flotation process for algae removal.

    PubMed

    Gao, Shanshan; Yang, Jixian; Tian, Jiayu; Ma, Fang; Tu, Gang; Du, Maoan

    2010-05-15

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density=1 mA/cm(2), pH=4-7, water temperature=18-36 degrees C, algae density=0.55 x 10(9)-1.55 x 10(9) cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m(3). The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view. PMID:20042280

  8. New records of marine algae in Vietnam

    NASA Astrophysics Data System (ADS)

    Le Hau, Nhu; Ly, Bui Minh; Van Huynh, Tran; Trung, Vo Thanh

    2015-06-01

    In May, 2013, a scientific expedition was organized by the Vietnam Academy of Science and Technology (VAST) and the Far Eastern Branch of the Russian Academy of Sciences (FEBRAS) through the frame of the VAST-FEBRAS International Collaboration Program. The expedition went along the coast of Vietnam from Quang Ninh to Kien Giang. The objective was to collect natural resources to investigate the biological and biochemical diversity of the territorial waters of Vietnam. Among the collected algae, six taxa are new records for the Vietnam algal flora. They are the red algae Titanophora pikeana (Dickie) Feldmann from Cu Lao Xanh Island, Laurencia natalensis Kylin from Tho Chu Island, Coelothrix irregularis (Harvey) Børgesen from Con Dao Island, the green algae Caulerpa oligophylla Montagne, Caulerpa andamanensis (W.R. Taylor) Draisma, Prudhomme et Sauvage from Phu Quy Island, and Caulerpa falcifolia Harvey & Bailey from Ly Son Island. The seaweed flora of Vietnam now counts 833 marine algal taxa, including 415 Rhodophyta, 147 Phaeophyceae, 183 Chlorophyta, and 88 Cyanobacteria.

  9. Antibody Production in Plants and Green Algae.

    PubMed

    Yusibov, Vidadi; Kushnir, Natasha; Streatfield, Stephen J

    2016-04-29

    Monoclonal antibodies (mAbs) have a wide range of modern applications, including research, diagnostic, therapeutic, and industrial uses. Market demand for mAbs is high and continues to grow. Although mammalian systems, which currently dominate the biomanufacturing industry, produce effective and safe recombinant mAbs, they have a limited manufacturing capacity and high costs. Bacteria, yeast, and insect cell systems are highly scalable and cost effective but vary in their ability to produce appropriate posttranslationally modified mAbs. Plants and green algae are emerging as promising production platforms because of their time and cost efficiencies, scalability, lack of mammalian pathogens, and eukaryotic posttranslational protein modification machinery. So far, plant- and algae-derived mAbs have been produced predominantly as candidate therapeutics for infectious diseases and cancer. These candidates have been extensively evaluated in animal models, and some have shown efficacy in clinical trials. Here, we review ongoing efforts to advance the production of mAbs in plants and algae. PMID:26905655

  10. [Pharmacology and toxicology of Spirulina alga].

    PubMed

    Chamorro, G; Salazar, M; Favila, L; Bourges, H

    1996-01-01

    Spirulina, a unicellular filamentous blue-green alga has been consumed by man since ancient times in Mexico and central Africa. It is currently grown in many countries by synthetic methods. Initially the interest in Spirulina was on its nutritive value: it was found almost equal to other plant proteins. More recently, some preclinical testing suggests it has several therapeutic properties such as hypocholesterolemic, immunological, antiviral and antimutagenic. This has led to more detailed evaluations such as nucleic acid content and presence of toxic metals, biogenic toxins and organic chemicals: they have shown absence or presence at tolerable levels according to the recommendations of international regulatory agencies. In animal experiments for acute, subchronic and chronic toxicity, reproduction, mutagenicity, and teratogenicity the algae did not cause body or organ toxicity. In all instances, the Spirulina administered to the animals were at much higher amounts than those expected for human consumption. On the other hand there is scant information of the effects of the algae in humans. This area needs more research. PMID:9005517

  11. Heterotrimeric G-proteins in green algae

    PubMed Central

    Hackenberg, Dieter; Pandey, Sona

    2014-01-01

    Heterotrimeric G-proteins (G-proteins, hereafter) are important signaling components in all eukaryotes. The absence of these proteins in the sequenced genomes of Chlorophycean green algae has raised questions about their evolutionary origin and prevalence in the plant lineage. The existence of G-proteins has often been correlated with the acquisition of embryophytic life-cycle and/or terrestrial habitats of plants which occurred around 450 million years ago. Our discovery of functional G-proteins in Chara braunii, a representative of the Charophycean green algae, establishes the existence of this conserved signaling pathway in the most basal plants and dates it even further back to 1–1.5 billion years ago. We have now identified the sequence homologs of G-proteins in additional algal families and propose that green algae represent a model system for one of the most basal forms of G-protein signaling known to exist to date. Given the possible differences that exist between plant and metazoan G-protein signaling mechanisms, such basal organisms will serve as important resources to trace the evolutionary origin of proposed mechanistic differences between the systems as well as their plant-specific functions. PMID:24614119

  12. Complete sequence of the mitochondrial DNA of the red alga Porphyra purpurea. Cyanobacterial introns and shared ancestry of red and green algae.

    PubMed Central

    Burger, G; Saint-Louis, D; Gray, M W; Lang, B F

    1999-01-01

    The mitochondrial DNA (mtDNA) of Porphyra purpurea, a circular-mapping genome of 36,753 bp, has been completely sequenced. A total of 57 densely packed genes has been identified, including the basic set typically found in animals and fungi, as well as seven genes characteristic of protist and plant mtDNAs and specifying ribosomal proteins and subunits of succinate:ubiquinone oxidoreductase. The mitochondrial large subunit rRNA gene contains two group II introns that are extraordinarily similar to those found in the cyanobacterium Calothrix sp, suggesting a recent lateral intron transfer between a bacterial and a mitochondrial genome. Notable features of P. purpurea mtDNA include the presence of two 291-bp inverted repeats that likely mediate homologous recombination, resulting in genome rearrangement, and of numerous sequence polymorphisms in the coding and intergenic regions. Comparative analysis of red algal mitochondrial genomes from five different, evolutionarily distant orders reveals that rhodophyte mtDNAs are unusually uniform in size and gene order. Finally, phylogenetic analyses provide strong evidence that red algae share a common ancestry with green algae and plants. PMID:10488235

  13. Hydrogenases in green algae: do they save the algae's life and solve our energy problems?

    PubMed

    Happe, Thomas; Hemschemeier, Anja; Winkler, Martin; Kaminski, Annette

    2002-06-01

    Green algae are the only known eukaryotes with both oxygenic photosynthesis and a hydrogen metabolism. Recent physiological and genetic discoveries indicate a close connection between these metabolic pathways. The anaerobically inducible hydA genes of algae encode a special type of highly active [Fe]-hydrogenase. Electrons from reducing equivalents generated during fermentation enter the photosynthetic electron transport chain via the plastoquinone pool. They are transferred to the hydrogenase by photosystem I and ferredoxin. Thus, the [Fe]-hydrogenase is an electron 'valve' that enables the algae to survive under anaerobic conditions. During sulfur deprivation, illuminated algal cultures evolve large quantities of hydrogen gas, and this promises to be an alternative future energy source. PMID:12049920

  14. Removal of Pb(2+) by biomass of marine algae.

    PubMed

    Hamdy, A A

    2000-10-01

    New biosorbent material derived from ubiquitous marine algae has been examined in packed-bed flow for Pb(2+) removal through sorption columns. Mixed biomass of marine algae has been used, consisting of representative species of the following algae: Ulva lactuca (green algae), Jania rubens (red algae), and Sargassum asperifolium (brown algae). A mixture of these three species showed a promising removal capacity for Pb(2+) from aqueous solution. Lead uptake up to 281.8 mg/g dry algal mixture was observed. Equilibrium was achieved after 120 min. No significant effect of changing the flow rate on the removal capacity was noticed. It was found that Langmuir model expresses the system at pH 4. Mineral acids exhibited good elution properties (a mean of 93%) for recovery of sorbed biomass ions as compared with the tested alkalies (about 60%). PMID:10977889

  15. Exploring the potential of algae/bacteria interactions.

    PubMed

    Kouzuma, Atsushi; Watanabe, Kazuya

    2015-06-01

    Algae are primary producers in aquatic ecosystems, where heterotrophic bacteria grow on organics produced by algae and recycle nutrients. Ecological studies have identified the co-occurrence of particular species of algae and bacteria, suggesting the presence of their specific interactions. Algae/bacteria interactions are categorized into nutrient exchange, signal transduction and gene transfer. Studies have examined how these interactions shape aquatic communities and influence geochemical cycles in the natural environment. In parallel, efforts have been made to exploit algae for biotechnology processes, such as water treatment and bioenergy production, where bacteria influence algal activities in various ways. We suggest that better understanding of mechanisms underlying algae/bacteria interactions will facilitate the development of more efficient and/or as-yet-unexploited biotechnology processes. PMID:25744715

  16. Effects of Cylindrospermopsin Producing Cyanobacterium and Its Crude Extracts on a Benthic Green Alga-Competition or Allelopathy?

    PubMed

    B-Béres, Viktória; Vasas, Gábor; Dobronoki, Dalma; Gonda, Sándor; Nagy, Sándor Alex; Bácsi, István

    2015-11-01

    Cylindrospermopsin (CYN) is a toxic secondary metabolite produced by filamentous cyanobacteria which could work as an allelopathic substance, although its ecological role in cyanobacterial-algal assemblages is mostly unclear. The competition between the CYN-producing cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum, and the benthic green alga Chlorococcum sp. was investigated in mixed cultures, and the effects of CYN-containing cyanobacterial crude extract on Chlorococcum sp. were tested by treatments with crude extracts containing total cell debris, and with cell debris free crude extracts, modelling the collapse of a cyanobacterial water bloom. The growth inhibition of Chlorococcum sp. increased with the increasing ratio of the cyanobacterium in mixed cultures (inhibition ranged from 26% to 87% compared to control). Interestingly, inhibition of the cyanobacterium growth also occurred in mixed cultures, and it was more pronounced than it was expected. The inhibitory effects of cyanobacterial crude extracts on Chlorococcum cultures were concentration-dependent. The presence of C. ovalisporum in mixed cultures did not cause significant differences in nutrient content compared to Chlorococcum control culture, so the growth inhibition of the green alga could be linked to the presence of CYN and/or other bioactive compounds. PMID:26528991

  17. Method for producing hydrogen and oxygen by use of algae

    DOEpatents

    Greenbaum, Elias

    1984-01-01

    Efficiency of process for producing H.sub.2 by subjecting algae in an aqueous phase to light irradiation is increased by culturing algae which has been bleached during a first period of irradiation in a culture medium in an aerobic atmosphere until it has regained color and then subjecting this algae to a second period of irradiation wherein hydrogen is produced at an enhanced rate.

  18. Method for producing hydrogen and oxygen by use of algae

    DOEpatents

    Greenbaum, E.

    1982-06-16

    Efficiency of process for producing H/sub 2/ by subjecting algae in an aqueous phase to light irradiation is increased by culturing algae which has been bleached during a first period of irradiation in a culture medium in an aerobic atmosphere until it has regained color and then subjecting this algae to a second period of irradiation wherein hydrogen is produced at an enhanced rate.

  19. Algae to Bio-Crude in Less Than 60 Minutes

    ScienceCinema

    Elliott, Doug

    2014-06-02

    Engineers have created a chemical process that produces useful crude oil just minutes after engineers pour in harvested algae -- a verdant green paste with the consistency of pea soup. The PNNL team combined several chemical steps into one continuous process that starts with an algae slurry that contains as much as 80 to 90 percent water. Most current processes require the algae to be dried -- an expensive process that takes a lot of energy. The research has been licensed by Genifuel Corp.

  20. Algae to Bio-Crude in Less Than 60 Minutes

    SciTech Connect

    Elliott, Doug

    2013-12-17

    Engineers have created a chemical process that produces useful crude oil just minutes after engineers pour in harvested algae -- a verdant green paste with the consistency of pea soup. The PNNL team combined several chemical steps into one continuous process that starts with an algae slurry that contains as much as 80 to 90 percent water. Most current processes require the algae to be dried -- an expensive process that takes a lot of energy. The research has been licensed by Genifuel Corp.

  1. Bromophenols from marine algae with potential anti-diabetic activities

    NASA Astrophysics Data System (ADS)

    Lin, Xiukun; Liu, Ming

    2012-12-01

    Marine algae contain various bromophenols with a variety of biological activities, including antimicrobial, anticancer, and anti-diabetic effects. Here, we briefly review the recent progress in researches on the biomaterials from marine algae, emphasizing the relationship between the structure and the potential anti-diabetic applications. Bromophenols from marine algae display their hyperglycemic effects by inhibiting the activities of protein tyrosine phosphatase 1B, α-glucosidase, as well as other mechanisms.

  2. Method and apparatus for iterative lysis and extraction of algae

    SciTech Connect

    Chew, Geoffrey; Boggs, Tabitha; Dykes, Jr., H. Waite H.; Doherty, Stephen J.

    2015-12-01

    A method and system for processing algae involves the use of an ionic liquid-containing clarified cell lysate to lyse algae cells. The resulting crude cell lysate may be clarified and subsequently used to lyse algae cells. The process may be repeated a number of times before a clarified lysate is separated into lipid and aqueous phases for further processing and/or purification of desired products.

  3. Diplosphaera sp. MM1 - A microalga with phycoremediation and biomethane potential.

    PubMed

    Liu, Cuixia; Subashchandrabose, Suresh R; Megharaj, Mallavarapu; Hu, Zhiquan; Xiao, Bo

    2016-10-01

    This study evaluated the potential of a microalga Diplosphaera sp. MM1 for its ability to generate energy through biomass production from wastewater remediation. 33% dairy wastewater and 50% winery wastewater demonstrated as promising alternative media for cultivating Diplosphaera sp. MM1 biomass. Interestingly, the alga cultivated in 50% winery wastewater with limited nitrogen produced the highest lipid content (43.07% total solid) and the lowest carbohydrate content (9.35% TS). On the contrary, the lowest lipid content (16.98% TS) and the highest carbohydrate content (29.39% TS) were exhibited by the alga cultivated in 33% dairy wastewater. The results from anaerobic digestion processes in terms of biochemical methane potential of the alga cultivated in BG-11 medium, 33% dairy wastewater and 50% winery wastewater were 197.39, 129.75 and 218.51NmLg(-1)VS, respectively. Further, this study demonstrates the potential of winery wastewater as a candidate to increase the lipid content of algae and enhance biofuel production of algal biomass. PMID:27472493

  4. 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

  5. Exploring the potential of using algae in cosmetics.

    PubMed

    Wang, Hui-Min David; Chen, Ching-Chun; Huynh, Pauline; Chang, Jo-Shu

    2015-05-01

    The applications of microalgae in cosmetic products have recently received more attention in the treatment of skin problems, such as aging, tanning and pigment disorders. There are also potential uses in the areas of anti-aging, skin-whitening, and pigmentation reduction products. While algae species have already been used in some cosmetic formulations, such as moisturizing and thickening agents, algae remain largely untapped as an asset in this industry due to an apparent lack of utility as a primary active ingredient. This review article focuses on integrating studies on algae pertinent to skin health and beauty, with the purpose of identifying serviceable algae functions in practical cosmetic uses. PMID:25537136

  6. Method and apparatus for lysing and processing algae

    DOEpatents

    Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite H.; Di Salvo, Roberto

    2013-03-05

    Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells at lower temperatures than existing algae processing methods. A salt or salt solution is used as a separation agent and to remove water from the ionic liquid, allowing the ionic liquid to be reused. The used salt may be dried or concentrated and reused. The relatively low lysis temperatures and recycling of the ionic liquid and salt reduce the environmental impact of the algae processing while providing biofuels and other useful products.

  7. Algae Bioreactor Using Submerged Enclosures with Semi-Permeable Membranes

    NASA Technical Reports Server (NTRS)

    Trent, Jonathan D (Inventor); Gormly, Sherwin J (Inventor); Embaye, Tsegereda N (Inventor); Delzeit, Lance D (Inventor); Flynn, Michael T (Inventor); Liggett, Travis A (Inventor); Buckwalter, Patrick W (Inventor); Baertsch, Robert (Inventor)

    2013-01-01

    Methods for producing hydrocarbons, including oil, by processing algae and/or other micro-organisms in an aquatic environment. Flexible bags (e.g., plastic) with CO.sub.2/O.sub.2 exchange membranes, suspended at a controllable depth in a first liquid (e.g., seawater), receive a second liquid (e.g., liquid effluent from a "dead zone") containing seeds for algae growth. The algae are cultivated and harvested in the bags, after most of the second liquid is removed by forward osmosis through liquid exchange membranes. The algae are removed and processed, and the bags are cleaned and reused.

  8. Sequencing of complete mitochondrial genome of brown algal Saccharina sp. ye-F.

    PubMed

    Fan, Xiao; Wang, Shuai; Xu, Dong; Zhang, Xiaowen; Xu, Le; Miao, Yu; Ye, Naihao

    2016-09-01

    The complete sequence (37 657 bp) of the mitochondrial DNA (mtDNA) of the Saccharina sp. ye-F was determined using Illumina sequencing data (Illumina Inc., San Diego, CA). The genome contains 38 protein-coding genes (PCG), three ribosomal RNA (rRNA), and 25 transfer RNA (tRNA) genes that are typical of Saccharina mtDNA. A phylogenetic analysis based on the mitochondrial genomes of brown algae indicated that Saccharina sp. ye-F and Saccharina longissima, Saccharina japonica are the most closely related species, which strongly supports their close phylogenetic affinity. PMID:26358639

  9. Inhibition of Microcystis aeruginosa by the extracellular substances from an Aeromonas sp.

    PubMed

    Liu, Yu-Mei; Chen, Ming-Jun; Wang, Meng-Hui; Jia, Rui-Bao; Li, Li

    2013-09-28

    Growth of Microcystis aeruginosa could be inhibited significantly within 24 h by the extracellular substances prepared from Aeromonas sp. strain FM. During the treatment, the concentration of extracellular soluble carbohydrates increased significantly in algal culture. Morphological and ultrastructural changes in M. aeruginosa cells, including breakage of the cell surface, secretion of mucilage, and intracellular disorganization of thylakoids, were observed. HPLC-MS analysis showed that the extracellular substances of Aeromonas sp. strain FM were a mixture of free amino acids, tripeptides, and clavulanate. Among these, the algae-lysis effects of lysine and clavulanate were confirmed. PMID:23727796

  10. Sequencing of complete mitochondrial genome of brown algal Saccharina sp. ye-W.

    PubMed

    Wang, Shuai; Fan, Xiao; Xu, Dong; Zhang, Xiaowen; Miao, Yu; Xu, Le; Ye, Naihao

    2016-07-01

    The complete sequence (37 657 bp) of the mitochondrial DNA (mtDNA) of the Saccharina sp. ye-W was determined using Illumina sequencing data. The genome contains 38 protein-coding genes (PCG), three ribosomal RNA (rRNA), 25 transfer RNA (tRNA) genes that are typical of Saccharina mtDNA. Phylogenetic analysis based on the mitochondrial genomes of brown algae indicated that Saccharina sp. ye-W and Saccharina longissima, Saccharina japonica are the most closely related species, which strongly supports their close phylogenetic affinity. PMID:26153752

  11. Alga-Derived Substrates Select for Distinct Betaproteobacterial Lineages and Contribute to Niche Separation in Limnohabitans Strains▿

    PubMed Central

    Šimek, Karel; Kasalický, Vojtěch; Zapomělová, Eliška; Horňák, Karel

    2011-01-01

    We examined the proportions of major Betaproteobacteria subgroups within bacterial communities in diverse nonaxenic, monospecific cultures of algae or cyanobacteria: four species of cryptophyta (genera Cryptomonas and Rhodomonas), four species of chlorophyta (genera Pediastrum, Staurastrum, and Chlamydomonas), and two species of cyanobacteria (genera Dolichospermum and Aphanizomenon). In the cryptophyta cultures, Betaproteobacteria represented 48 to 71% of total bacteria, the genus Limnohabitans represented 18 to 26%, and the Polynucleobacter B subcluster represented 5 to 16%. In the taxonomically diverse chlorophyta group, the genus Limnohabitans accounted for 7 to 45% of total bacteria. In contrast, cyanobacterial cultures contained significantly lower proportions of the Limnohabitans bacteria (1 to 3% of the total) than the cryptophyta and chlorophyta cultures. Notably, largely absent in all of the cultures was Polynucleobacter necessarius (Polynucleobacter C subcluster). Subsequently, we examined the growth of Limnohabitans strains in the presence of different algae or their extracellular products (EPP). Two strains, affiliated with Limnohabitans planktonicus and Limnohabitans parvus, were separately inoculated into axenic cultures of three algal species growing in an inorganic medium: Cryptomonas sp., Chlamydomonas noctigama, and Pediastrum boryanum. The Limnohabitans strains cocultured with these algae or inoculated into their EPP consistently showed (i) pronounced population growth compared to the control without the algae or EPP and (ii) stronger growth stimulation of L. planktonicus than of L. parvus. Overall, growth responses of the Limnohabitans strains cultured with algae were highly species specific, which suggests a pronounced niche separation between two closely related Limnohabitans species likely mediated by different abilities to utilize the substrates produced by different algal species. PMID:21873481

  12. Alga-derived substrates select for distinct Betaproteobacterial lineages and contribute to niche separation in Limnohabitans strains.

    PubMed

    Simek, Karel; Kasalický, Vojtĕch; Zapomĕlová, Eliska; Hornák, Karel

    2011-10-01

    We examined the proportions of major Betaproteobacteria subgroups within bacterial communities in diverse nonaxenic, monospecific cultures of algae or cyanobacteria: four species of cryptophyta (genera Cryptomonas and Rhodomonas), four species of chlorophyta (genera Pediastrum, Staurastrum, and Chlamydomonas), and two species of cyanobacteria (genera Dolichospermum and Aphanizomenon). In the cryptophyta cultures, Betaproteobacteria represented 48 to 71% of total bacteria, the genus Limnohabitans represented 18 to 26%, and the Polynucleobacter B subcluster represented 5 to 16%. In the taxonomically diverse chlorophyta group, the genus Limnohabitans accounted for 7 to 45% of total bacteria. In contrast, cyanobacterial cultures contained significantly lower proportions of the Limnohabitans bacteria (1 to 3% of the total) than the cryptophyta and chlorophyta cultures. Notably, largely absent in all of the cultures was Polynucleobacter necessarius (Polynucleobacter C subcluster). Subsequently, we examined the growth of Limnohabitans strains in the presence of different algae or their extracellular products (EPP). Two strains, affiliated with Limnohabitans planktonicus and Limnohabitans parvus, were separately inoculated into axenic cultures of three algal species growing in an inorganic medium: Cryptomonas sp., Chlamydomonas noctigama, and Pediastrum boryanum. The Limnohabitans strains cocultured with these algae or inoculated into their EPP consistently showed (i) pronounced population growth compared to the control without the algae or EPP and (ii) stronger growth stimulation of L. planktonicus than of L. parvus. Overall, growth responses of the Limnohabitans strains cultured with algae were highly species specific, which suggests a pronounced niche separation between two closely related Limnohabitans species likely mediated by different abilities to utilize the substrates produced by different algal species. PMID:21873481

  13. 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

  14. Integrated Bacillus sp. immobilized cell reactor and Synechocystis sp. algal reactor for the treatment of tannery wastewater.

    PubMed

    Sekaran, G; Karthikeyan, S; Nagalakshmi, C; Mandal, A B

    2013-01-01

    The wastewater discharged from leather industries lack biodegradability due to the presence of xenobiotic compounds. The primary clarification and aerobic treatment in Bacillus sp. immobilized Chemo Autotrophic Activated Carbon Oxidation (CAACO) reactor removed considerable amount of pollution parameters. The residual untreated organics in the wastewater was further treated in algal batch reactor inoculated with Synechocystis sp. Sodium nitrate, K(2)HPO(4), MgSO(4).7H(2)O, NH(4)Cl, CaCl(2)·2H(2)O, FeCl(3) (anhydrous), and thiamine hydrochloride, rice husk based activated carbon (RHAC), immobilization of Bacillus sp. in mesoporous activated carbon, sand filter of dimensions diameter, 6 cm and height, 30 cm; and the CAACO reactor of dimensions diameter, 5.5 cm and height, 30 cm with total volume 720 ml, and working volume of 356 ml. In the present investigation, the CAACO treated tannery wastewater was applied to Synechocystis sp. inoculated algal batch reactor of hydraulic residence time 24 h. The BOD(5), COD, and TOC of treated wastewater from algal batch reactor were 20 ± 7, 167 ± 29, and 78 ± 16 mg/l respectively. The integrated CAACO system and Algal batch reactor was operated for 30 days and they accomplished a cumulative removal of BOD(5),COD, TOC, VFA and sulphide as 98 %, 95 %, 93 %, 86 %, and 100 %, respectively. The biokinetic constants for the growth of algae in the batch reactor were specific growth rate, 0.095(day(-1)) and yield coefficient, 3.15 mg of algal biomass/mg of COD destructed. The degradation of xenobiotic compounds in the algal batch reactor was confirmed through HPLC and FT-IR techniques. The integrated CAACO-Algal reactor system established a credible reduction in pollution parameters in the tannery wastewater. The removal mechanism is mainly due to co-metabolism between algae and bacterial species and the organics were completely metabolized rather than by adsorption. PMID:22528997

  15. Organic carbon, influent microbial diversity and temperature strongly influence algal diversity and biomass in raceway ponds treating raw municipal wastewater.

    PubMed

    Cho, Dae-Hyun; Ramanan, Rishiram; Heo, Jina; Kang, Zion; Kim, Byung-Hyuk; Ahn, Chi-Yong; Oh, Hee-Mock; Kim, Hee-Sik

    2015-09-01

    Algae based wastewater treatment coupled to biofuel production has financial benefits and practical difficulties. This study evaluated the factors influencing diversity and growth of indigenous algal consortium cultivated on untreated municipal wastewater in a high rate algal pond (HRAP) for a period of 1 year using multivariate statistics. Diversity analyses revealed the presence of Chlorophyta, Cyanophyta and Bacillariophyta. Dominant microalgal genera by biovolume in various seasons were Scenedesmus sp., Microcystis sp., and Chlorella sp. Scenedesmus sp., persisted throughout the year but none of three strains co-dominated with the other. The most significant factors affecting genus dominance were temperature, inflow cyanophyta and organic carbon concentration. Cyanophyta concentration affected microalgal biomass and diversity, whereas temperature impacted biomass. Preferred diversity of microalgae is not sustained in wastewater systems but is obligatory for biofuel production. This study serves as a guideline to sustain desired microalgal consortium in wastewater treatment plants for biofuel production. PMID:25746593

  16. Inorganic carbon acquisition in some synurophyte algae.

    PubMed

    Bhatti, Shabana; Colman, Brian

    2008-05-01

    Some characteristics of photosynthesis of three synurophyte algae, Synura petersenii, Synura uvella and Tessellaria volvocina were investigated to determine the mechanism of inorganic carbon (C(i)) uptake. All three species were found to have no external carbonic anhydrase, no capacity for direct bicarbonate uptake and a low whole-cell affinity for C(i). The internal pH of S. petersenii determined using (14)C-benzoic acid and [2-(14)C]-5,5-dimethyloxazolidine-2,4-dione was pH 7.0-7.5, over an external pH range of 5.0-7.5. Thus, the pH difference between the cell interior of S. petersenii and the external medium was large enough, over the alga's growth range, to allow the accumulation of C(i) by the diffusive uptake of CO(2). Monitoring O(2) evolution and CO(2) uptake by suspensions of S. petersenii at pH 7.0 by mass spectrometry did not indicate a rapid uptake of CO(2), and the final CO(2) compensation concentration reached was 24 +/- 0.7 microM. Furthermore, when the cells were darkened, a brief burst of CO(2) occurred before a steady rate of dark respiration was established, suggesting a loss of CO(2) by photorespiration. An examination of the kinetics of ribulose-1,5-bisphosphate carboxylase/oxygenase in homogenates of cells of S. petersenii, S. uvella and Mallomonas papillosa showed that values of the K(m) (CO(2)) were 28.4, 41.8 and 18.2 microM, respectively. These species lack the characteristics of cells with a CO(2)-concentrating mechanism because the cell affinity for C(i) appears to be determined by the relatively high CO(2) affinity of the Rubisco of these algae. PMID:18298411

  17. A technical evaluation of biodiesel from vegetable oils vs. algae. Will algae-derived biodiesel perform?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel, one of the most prominent renewable alternative fuels, can be derived from a variety of sources including vegetable oils, animal fats and used cooking oils as well as alternative sources such as algae. While issues such as land-use change, food vs. fuel, feedstock availability, and produc...

  18. 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

  19. Pheromones in marine algae: A technical approach

    NASA Astrophysics Data System (ADS)

    Gassmann, G.; Müller, D. G.; Fritz, P.

    1995-03-01

    It is now well known that many marine organisms use low-molecular volatile substances as signals, in order to coordinate activities between different individuals. The study of such pheromones requires the isolation and enrichment of the secretions from undisturbed living cells or organisms over extended periods of time. The Grob-Hersch extraction device, which we describe here, avoids adverse factors for the biological materials such as strong water currents, rising gas bubbles or chemical solvents. Furthermore, the formation of sea-water spray is greatly reduced. The application of this technique for the isolation of pheromones of marine algae and animals is described.

  20. Factors affecting spore germination in algae - review.

    PubMed

    Agrawal, S C

    2009-01-01

    This review surveys whatever little is known on the influence of different environmental factors like light, temperature, nutrients, chemicals (such as plant hormones, vitamins, etc.), pH of the medium, biotic factors (such as algal extracellular substances, algal concentration, bacterial extracellular products, animal grazing and animal extracellular products), water movement, water stress, antibiotics, UV light, X-rays, gamma-rays, and pollution on the spore germination in algae. The work done on the dormancy of algal spores and on the role of vegetative cells in tolerating environmental stress is also incorporated. PMID:19826917

  1. Algae Biofuels Co-Location Assessment Tool

    2013-09-18

    ABCLAT was built to help any model user with spatially explicit Nitrogen, Phosphorous, and Carbon Dioxide nutrient flux information, and solar resource information evaluate algal cultivation potential. Initial applications of this modeling framework include Algae Biofuels Co-Location Assessment Tool Canada and Australia. The Canadian application was copyrighted November 29th 2011 as the Algae Biofuels Co-Location Assessment Tool for Canada. This copyright assertion is for the general framework from which any country or region with themore » requisite data could create a regionally specific application. The ABCLAT model framework developed by SNL looks at the growth potential in a given region as a function of available nutrients from wastewater and other sources, carbon dioxide from power plants, available solar potential, and if available, land cover and use information. The model framework evaluates the biomass potential, fixed carbon dioxide, potential algal biocrude and required land area for nutrient sources. ABCLAT is built with an object-oriented software program that can provide an easy to use interface for exploring questions related to aigal biomass production.« less

  2. Viruses and viruslike particles of eukaryotic algae.

    PubMed Central

    Van Etten, J L; Lane, L C; Meints, R H

    1991-01-01

    Until recently there was little interest or information on viruses and viruslike particles of eukaryotic algae. However, this situation is changing. In the past decade many large double-stranded DNA-containing viruses that infect two culturable, unicellular, eukaryotic green algae have been discovered. These viruses can be produced in large quantities, assayed by plaque formation, and analyzed by standard bacteriophage techniques. The viruses are structurally similar to animal iridoviruses, their genomes are similar to but larger (greater than 300 kbp) than that of poxviruses, and their infection process resembles that of bacteriophages. Some of the viruses have DNAs with low levels of methylated bases, whereas others have DNAs with high concentrations of 5-methylcytosine and N6-methyladenine. Virus-encoded DNA methyltransferases are associated with the methylation and are accompanied by virus-encoded DNA site-specific (restriction) endonucleases. Some of these enzymes have sequence specificities identical to those of known bacterial enzymes, and others have previously unrecognized specificities. A separate rod-shaped RNA-containing algal virus has structural and nucleotide sequence affinities to higher plant viruses. Quite recently, viruses have been associated with rapid changes in marine algal populations. In the next decade we envision the discovery of new algal viruses, clarification of their role in various ecosystems, discovery of commercially useful genes in these viruses, and exploitation of algal virus genetic elements in plant and algal biotechnology. Images PMID:1779928

  3. Effects of nitrogen dioxide on algae

    SciTech Connect

    Wodzinski, R.S.; Alexander, M.

    1980-01-01

    Photosynthetic activity of Anabaena flos-aquae in a soil suspension at an initial pH of 4.9 was almost totally eliminated after 3 days of exposure to 5.0 ppm (..mu..l/liter) NO/sub 2/, at which time the pH had fallen to 3.9. In contrast, A. flos-aquae in soil suspensions at an initial pH of 6.0 was not inhibited after 3 days by 5.0 ppm NO/sub 2/, but the activity was reduced by half in the presence of 15.0 ppm NO/sub 2/; the pH was 6.5 and 5.8, respectively, in the NO/sub 2/-treated samples on day 3. Photosynthesis by the green algae Chlamydomonas reinhardtii and Ankistrodesmus falcatus in soil suspensions at an initial pH of approx 4.2 was not appreciably affected by 15.0 ppm of NO/sub 2/ after 3 days, at which time the pH had fallen below 4.0. The high levels of NO/sub 2/ and low pH values required for toxicity suggest that blue-green and green algae probably will not be affected directly by NO/sub 2/ in polluted air.

  4. Effects of nitrogen dioxide on algae

    SciTech Connect

    Wodzinski, R.S.; Alexander, M.

    1980-01-01

    Photosynthetic activity of Anabaena flos-aquae in a soil suspension at an initial pH of 4.9 was almost totally eliminated after 3 days of exposure to 5.0 ppM (..mu..l/liter) NO/sub 2/, at which time the pH had fallen to 3.9. In contrast, A. flos-aquae in soil suspensions at an initial pH of 6.0 was not inhibited after 3 days by 5.0 ppM NO/sub 2/, but the activity was reduced by half in the presence of 15.0 ppM NO/sub 2/; the pH was 6.5 and 5.8, respectively, in the NO/sub 2/-treated samples on day 3. Photosynthesis by the green algae Chlamydomonas reinhardtii and Ankistrodesmus falcatus in soil suspensions at an initial pH of approx. 4.2 was not appreciably affected by 15.0 ppM of NO/sub 2/ after 3 days, at which time the pH had fallen below 4.0. The high levels of NO/sub 2/ and low pH values required for toxicity suggest that blue-green and green algae probably will not be affected directly by NO/sub 2/ in polluted air.

  5. Algae Biofuels Co-Location Assessment Tool

    SciTech Connect

    2013-09-18

    ABCLAT was built to help any model user with spatially explicit Nitrogen, Phosphorous, and Carbon Dioxide nutrient flux information, and solar resource information evaluate algal cultivation potential. Initial applications of this modeling framework include Algae Biofuels Co-Location Assessment Tool Canada and Australia. The Canadian application was copyrighted November 29th 2011 as the Algae Biofuels Co-Location Assessment Tool for Canada. This copyright assertion is for the general framework from which any country or region with the requisite data could create a regionally specific application. The ABCLAT model framework developed by SNL looks at the growth potential in a given region as a function of available nutrients from wastewater and other sources, carbon dioxide from power plants, available solar potential, and if available, land cover and use information. The model framework evaluates the biomass potential, fixed carbon dioxide, potential algal biocrude and required land area for nutrient sources. ABCLAT is built with an object-oriented software program that can provide an easy to use interface for exploring questions related to aigal biomass production.

  6. Video micrography of algae photomovement and vectorial method of biomonitoring

    NASA Astrophysics Data System (ADS)

    Posudin, Yuri I.; Massjuk, N. P.; Lilitskaya, G. G.

    1996-01-01

    The simultaneous recording of several photomovement parameters of algae as test-functions during biomonitoring is proposed. Green alga Dunaliella viridis Teod. was used as the test- object for the estimation of different heavy metals. The quantitative changes of photomovement parameters as a criterion of toxicity were determined by means of the vectorial method of biomonitoring.

  7. Comments on the Manuscript, "Biodiesel Production from Freshwater Algae"

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recent publication (Vijayaragahavan, K.; Hemanathan, K., Biodiesel from freshwater algae, Energy Fuels, 2009, 23(11):5448-5453) on fuel production from algae is evaluated. It is discussed herein that the fuel discussed in that paper is not biodiesel, rather it probably consists of hydrocarbons. ...

  8. Evaluation of Culture Conditions to Obtain Fatty Acids from Saline Microalgae Species: Dunaliella salina, Sinecosyfis sp., and Chroomonas sp.

    PubMed Central

    Castilla Casadiego, D. A.; Albis Arrieta, A. R.; Angulo Mercado, E. R.; Cervera Cahuana, S. J.; Baquero Noriega, K. S.; Suárez Escobar, A. F.; Morales Avendaño, E. D.

    2016-01-01

    The use of the saline microalgae, Dunaliella salina, Sinecosyfis sp., and Chroomonas sp., was explored as an alternative source for the production of fatty acids using fertilizer and glycerol as culture media. The nutrient medium used contained “Nutrifoliar,” a commercial fertilizer, and/or glycerol, in natural sea water. The microalgae were placed in cultures with different conditions. The parameters that favored the largest production of fatty acids were 24 hours of agitation and illumination, 1620 L/day of air supply, 2.25 L of air/min, and a temperature of 32°C using “Nutrifoliar” as the culture media. Results indicated that, from 3 g of microalgae in wet base of Chroomonas sp., 54.43 mg of oil was produced. The chromatographic characterization of oil obtained revealed the presence of essential fatty acids such as 9,12,15-octadecatrienoic acid (omega-3) and 4,7,10-hexadecatrienoic acid (omega-6) from the species Dunaliella salina. On the other hand, 9,12-octadecadienoic acid (omega-6) and cis-11-eicosenoic acid (omega-9) were identified from the species Chroomonas sp. The temperature variations played an important role in the velocity of growth or the production of the algae biomass, the amount of oil, and the ability to produce fatty acids. PMID:27376085

  9. Algae Farming in Low Earth Orbit: Past Present and Future

    NASA Astrophysics Data System (ADS)

    Morrison, N.

    Algal strains used as a production engine represent a novel example of living mechanical systems with tremendous potential for applications in space. Algae use photosynthesis to create lipids, glycerin, and biomass, with different strains of algae producing different oils. Algae can be grown to produce many types of oils, with low, medium or long hydrocarbon chain lengths. This article examines the history of algae research, as well as its value to astronauts as both a food supplement and as an oxygen production and carbon sequester engine. Consideration is given to ways algae is currently being used and tested in space, followed by a look forward envisioning dynamic living technological systems that can help to sustain our race as we travel the void between stars.

  10. Cryoalgotox: Use of cryopreserved alga in a semistatic microplate test

    SciTech Connect

    Benhra, A.; Radetski, C.M.; Ferard, J.F.

    1997-03-01

    Use of cryopreserved alga Selenastrum capricornutum has been evaluated as a simple and cost-efficient procedure in a new semistatic algal ecotoxicity test. Experiments have been conducted to compare performance criteria of this method, named Cryoalgotox, versus the classic microplate test using fresh algae. Cryoalgotox 72-h 50% effective concentrations (EC50s) determined with Cd{sup 2+}, Cu{sup 2+}, Cr{sup 6+}, and atrazine were more sensitive, repeatable (low coefficients of variation), and reproducible (low time effect) than the results obtained with the classical microplate tests. The effect of storage time at {minus}80 C on the sensitivity of the algae was assessed using cadmium as a toxic reference; it was shown that algae stored at {minus}80 C over a 3-month period gave comparable toxicity results to those found with fresh algae.

  11. Comparative Studies on Plastoquinones. IV. Plastoquinones in Algae

    PubMed Central

    Sun, Elena; Barr, Rita; Crane, F. L.

    1968-01-01

    Plastoquinones A and C have been found in all classes of algae, including representatives of greens, yellow-greens, blue-greens, reds, browns and the flagellate, Euglena. Plastoquinone C from red and brown algae can be separated into 6 different types. An additional plastoquinone C has been found in Gigartina and Rhydomela. From chromatographic evidence this may be equivalent to plastoquinone Co, a C type with a hydroxyl group on the first isoprene unit of the terpenoid sidechain of this substituted benzo-quinone. The ubiquinone, vitamin K and α-tocopherylquinone content of several algae is also reported. The presence of plastoquinone A in all green plants and many algae indicates that it may be a functional element in photosynthesis. Our study shows that plastoquinone C is more regularly present in algae than has been previously shown. PMID:16656993

  12. [Marine algae of Baja California Sur, Mexico: nutritional value].

    PubMed

    Carrillo Domínguez, Silvia; Casas Valdez, Margarita; Ramos Ramos, Felipe; Pérez-Gil, Fernando; Sánchez Rodríguez, Ignacio

    2002-12-01

    The Baja California Peninsula is one of the richest regions of seaweed resources in México. The objective of this study was to determine the chemical composition of some marine algae species of Baja California Sur, with an economical potential due to their abundance and distribution, and to promote their use as food for human consumption and animal feeding. The algae studied were Green (Ulva spp., Enteromorpha intestinalis, Caulerpa sertularoides, Bryopsis hypnoides), Red (Laurencia johnstonii, Spyridia filamentosa, Hypnea valentiae) and Brown (Sargassum herporizum, S. sinicola, Padina durvillaei, Hydroclathrus clathrathus, Colpomenia sinuosa). The algae were dried and ground before analysis. In general, the results showed that algae had a protein level less than 11%, except L. johnstonii with 18% and low energy content. The ether extract content was lower than 1%. However, the algae were a good source of carbohydrates and inorganic matter. PMID:12868282

  13. Mitigating ammonia nitrogen deficiency in dairy wastewaters for algae cultivation.

    PubMed

    Lu, Qian; Zhou, Wenguang; Min, Min; Ma, Xiaochen; Ma, Yiwei; Chen, Paul; Zheng, Hongli; Doan, Yen T T; Liu, Hui; Chen, Chi; Urriola, Pedro E; Shurson, Gerald C; Ruan, Roger

    2016-02-01

    This study demonstrated that the limiting factor to algae growth on dairy wastewater was the ammonia nitrogen deficiency. Dairy wastewaters were mixed with a slaughterhouse wastewater that has much higher ammonia nitrogen content. The results showed the mixing wastewaters improved the nutrient profiles and biomass yield at low cost. Algae grown on mixed wastewaters contained high protein (55.98-66.91%) and oil content (19.10-20.81%) and can be exploited to produce animal feed and biofuel. Furthermore, algae grown on mixed wastewater significantly reduced nutrient contents remained in the wastewater after treatment. By mitigating limiting factor to algae growth on dairy wastewaters, the key issue of low biomass yield of algae grown on dairy wastewaters was resolved and the wastewater nutrient removal efficiency was significantly improved by this study. PMID:26623940

  14. Red Algae (Rhodophyta) from the Coast of Madagascar: Preliminary Bioactivity Studies and Isolation of Natural Products.

    PubMed

    Rahelivao, Marie Pascaline; Gruner, Margit; Andriamanantoanina, Hanta; Andriamihaja, Bakolinirina; Bauer, Ingmar; Knölker, Hans-Joachim

    2015-07-01

    Several species of red algae (Rhodophyta) from the coastal regions of Madagascar have been investigated for their natural products. The most abundant compound was cholesterol (5) in combination with a series of oxidized congeners. The brominated indoles 1-3 along with the sesquiterpene debilone (4) have been isolated from Laurencia complanata. For the first time, debilone (4) has been obtained from a marine plant. From the methanol extract of Calloseris sp., we have achieved the second isolation of the unusual A-ring contracted steroids (-)-2-ethoxycarbonyl-2β-hydroxy-A-nor-cholest-5-en-4-one (9) and phorbasterone B (10). The crude extracts of Laurencia complanata exhibited antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Streptococcus pneumoniae, and Candida albicans. PMID:26198236

  15. Red Algae (Rhodophyta) from the Coast of Madagascar: Preliminary Bioactivity Studies and Isolation of Natural Products

    PubMed Central

    Rahelivao, Marie Pascaline; Gruner, Margit; Andriamanantoanina, Hanta; Andriamihaja, Bakolinirina; Bauer, Ingmar; Knölker, Hans-Joachim

    2015-01-01

    Several species of red algae (Rhodophyta) from the coastal regions of Madagascar have been investigated for their natural products. The most abundant compound was cholesterol (5) in combination with a series of oxidized congeners. The brominated indoles 1–3 along with the sesquiterpene debilone (4) have been isolated from Laurencia complanata. For the first time, debilone (4) has been obtained from a marine plant. From the methanol extract of Calloseris sp., we have achieved the second isolation of the unusual A-ring contracted steroids (−)-2-ethoxycarbonyl-2β-hydroxy-A-nor-cholest-5-en-4-one (9) and phorbasterone B (10). The crude extracts of Laurencia complanata exhibited antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Streptococcus pneumoniae, and Candida albicans. PMID:26198236

  16. The influence of nitrogen on heterocyst production in blue-green algae

    USGS Publications Warehouse

    Ogawa, Roann E.; Carr, John F.

    1969-01-01

    A series of experiments on heterocyst production in Anabaena variabilis provides some strong indirect evidence for the role of heterocysts in nitrogen fixation. Of the algae tested (Anabaena variabilis, A. inaequalis, A. cylindrica, A. flos-aquae, Tolypothrix distorta, Gloeotrichia echinulata, Aphanizomenon flos-aquae, Oscillatoria sp., and Microcystis aeruginosa), only those with heterocysts grew in a nitrate-free medium. Growth in the nitrate-free medium was accompanied by an increase in heterocysts. Heterocyst formation in A. variabilis was evident 24 hr after transfer from a nitrate-containing to a nitrate-free medium. The number of heterocysts was altered by changes in the nitrogen source. Numbers were lowest when NH4-N was used as a nitrogen source and highest when nitrogen (N2-N) was derived from the atmosphere. Heterocyst numbers could also be regulated by controlling the concentration of NO3-N in the medium. Heterocyst production depended on the absence of combined nitrogen and the presence of phosphate. Data are presented on the occurrence of blue-green algae (with heterocysts) in Lake Erie and the environmental conditions apparently necessary for them to become dominant.

  17. Response of benthic algae to environmental gradients in an agriculturally dominated landscape

    USGS Publications Warehouse

    Munn, M.D.; Black, R.W.; Gruber, S.J.

    2002-01-01

    Benthic algal communities were assessed in an agriculturally dominated landscape in the Central Columbia Plateau, Washington, to determine which environmental variables best explained species distributions, and whether algae species optima models were useful in predicting specific water-quality parameters. Land uses in the study area included forest, range, urban, and agriculture. Most of the streams in this region can be characterized as open-channel systems influenced by intensive dryland (nonirrigated) and irrigated agriculture. Algal communities in forested streams were dominated by blue-green algae, with communities in urban and range streams dominated by diatoms. The predominance of either blue-greens or diatoms in agricultural streams varied greatly depending on the specific site. Canonical correspondence analysis (CCA) indicated a strong gradient effect of several key environmental variables on benthic algal community composition. Conductivity and % agriculture were the dominant explanatory variables when all sites (n = 24) were included in the CCA; water velocity replaced conductivity when the CCA included only agricultural and urban sites. Other significant explanatory variables included dissolved inorganic nitrogen (DIN), orthophosphate (OP), discharge, and precipitation. Regression and calibration models accurately predicted conductivity based on benthic algal communities, with OP having slightly lower predictability. The model for DIN was poor, and therefore may be less useful in this system. Thirty-four algal taxa were identified as potential indicators of conductivity and nutrient conditions, with most indicators being diatoms except for the blue-greens Anabaenasp. and Lyngbya sp.

  18. Cenoses of phototrophic algae of ultrasaline lakes in the Kulunda steppe (Altai krai, Russian Federation)

    NASA Astrophysics Data System (ADS)

    Sapozhnikov, Ph. V.; Kalinina, O. Yu.; Nikitin, M. A.; Samylina, O. S.

    2016-01-01

    In 2012, expeditions of the Institute of Microbiology, Russian Academy of Sciences, delivered samples of algo-bacterial mats from Kulunda steppe alkaline lakes (Petukhovskoe alkaline lake, Tanatar VI, and Gorchina III). The filamentous alga Ctenocladus circinnatus (Chlorophyta) acted as an edificator of the mats. The composition of cenoses algocomponents also included chlorophytes Dunaliella viridis and Picocystis salinarum as well as diatoms Anomeoneis sphaerophora, Brachysira brebissonii, B. zellensis, Mastogloia pusilla var. subcapitata, Nitzschia amphibia, N. cf. communis, and Nitzschia sp. 1. The composition and structure of phototrophic algae cenoses (including diatom taxocenes) were described for the investigated lakes for the first time. For the period from 2011 to 2012, the total mineralization significantly increased in lakes. This involved sensible alterations of cenoses. B. zellensis was the most permanent component of diatom taxocenes in both seasons. In the summer of 2011, it was often accompanied by A. sphaerophora and B. brebissonii. In the summer of 2012, A. sphaerophora was found only singularly in Lake Gorchina III, and some biotopes of Lake Tanatar VI were massively inhabited by N. cf. communis, including colonies that had not been previously described for the species. The genetic analysis of three diatoms, which are markedly different from each other in their appearance and were sampled from different lakes but were all determined as Nitzschia cf. communis, showed their complete similarity to each other with the 18S rRNA gene fragment and the highest similarity of all the three diatoms with the species Nitzschia communis.

  19. Host specificity and growth of kelp gametophytes symbiotic with filamentous red algae (Ceramiales, Rhodophyta)

    NASA Astrophysics Data System (ADS)

    Hubbard, Charlene B.; Garbary, David J.; Kim, Kwang Young; Chiasson, David M.

    2004-02-01

    Kelp gametophytes were previously observed in nature living endophytically in red algal cell walls. Here we examine the interactions of two kelp species and six red algae in culture. Gametophytes of Nereocystis luetkeana (Mertens) Postels et Ruprecht became endophytic in the cell walls of Griffithsia pacifica Kylin and Antithamnion defectum Kylin, and grew epiphytically in high abundance on G. japonica Okamura and Aglaothamnion oosumiense Itono. Alaria esculenta (Linnaeus) Greville from the Atlantic coast of Nova Scotia became endophytic in Aglaothamnion oosumiense, Antithamnion defectum, Callithamnion sp., G. japonica, G. pacifica, and Pleonosporium abysicola Gardner, all from the Pacific Ocean. Some cultures were treated with phloroglucinol before infection to thicken the cell walls. The endophytic gametophytes were smaller and grew more slowly than gametophytes epiphytic on the same host. N. luetkeana failed to become endophytic in some of the potential hosts, and this may reflect host specificity, or culture artifacts. This work improves our understanding of the process of infection of red algae by kelp gametophytes, and broadens our knowledge of host specificity in endophytic symbioses.

  20. Enhanced accumulation of PCB congeners by Baltic Sea blue mussels, Mytilus edulis, with increased algae enrichment

    SciTech Connect

    Gilek, M.; Bjoerk, M.; Broman, D.; Kautsky, N.; Naef, C.

    1996-09-01

    The objective of this study was to examine if natural variations in the quantity of phytoplankton-derived particulate and dissolved organic carbon influences the accumulation of polychlorinated biphenyls (PCBs) in the tissues of Baltic Sea blue mussels (Mytilus edulis L.). In a laboratory flow-through experiment the authors exposed M. edulis to the technical PCB mixture Aroclor{reg_sign} 1248 for 21 d at three different enrichments of the unicellular green algae Chlamydomonas sp., 0.10, 0.16, and 0.32 mg particulate organic carbon (POC)/L. Tissue and water concentrations were determined for seven PCB congeners and 21-d bioaccumulation factors were calculated against total water concentrations. Contrary to what would be expected, an increase in algae enrichment from 0.10 to 0.32 mg POC/L resulted in an enhanced PCB accumulation by a factor of approx. 2. This increase in PCB accumulation was more pronounced for PCB congeners with lower hydrophobicity. These observations have implications for the design of laboratory accumulation studies and potentially for PCB accumulation and cycling in field populations of suspension-feeding mussels in response to changes in eutrophication status.

  1. Growth of Chlamydomonas reinhardtii in acetate-free medium when co-cultured with alginate-encapsulated, acetate-producing strains of Synechococcus sp. PCC 7002

    DOE PAGESBeta

    Therien, Jesse B.; Zadvornyy, Oleg A.; Posewitz, Matthew C.; Bryant, Donald A.; Peters, John W.

    2014-10-18

    The model alga Chlamydomonas reinhardtii requires acetate as a co-substrate for optimal production of lipids, and the addition of acetate to culture media has practical and economic implications for algal biofuel production. We demonstrate the growth of C. reinhardtii on acetate provided by mutant strains of the cyanobacterium Synechococcus sp. PCC7002.

  2. Heterococcus endolithicus sp. nov. (Xanthophyceae) and other terrestrial Heterococcus species from Antarctica: morphological changes during life history and response to temperature

    NASA Technical Reports Server (NTRS)

    Darling, R. B.; Friedmann, E. I.; Broady, P. A.

    1987-01-01

    Strains of Heterococcus endolithicus sp. nov., H. pleurococcoides Pitschmann, H. caespitosus Vischer, and H. protonematoides Vischer isolated from terrestrial habitats in Antarctica were studied in culture. Morphology of the algae changes with stage in life history. The characteristic branching patterns are not present in very young or old cultures. Filament formation is suppressed when cultures are grown outside their optimal temperature range.

  3. Factors determining growth and vertical distribution of planktonic algae in extremely acidic mining lakes (pH 2.7)

    NASA Astrophysics Data System (ADS)

    Bissinger, Vera

    2003-04-01

    In this thesis, I investigated the factors influencing the growth and vertical distribution of planktonic algae in extremely acidic mining lakes (pH 2-3). In the focal study site, Lake 111 (pH 2.7; Lusatia, Germany), the chrysophyte, Ochromonas sp., dominates in the upper water strata and the chlorophyte, Chlamydomonas sp., in the deeper strata, forming a pronounced deep chlorophyll maximum (DCM). Inorganic carbon (IC) limitation influenced the phototrophic growth of Chlamydomonas sp. in the upper water strata. Conversely, in deeper strata, light limited its phototrophic growth. When compared with published data for algae from neutral lakes, Chlamydomonas sp. from Lake 111 exhibited a lower maximum growth rate, an enhanced compensation point and higher dark respiration rates, suggesting higher metabolic costs due to the extreme physico-chemical conditions. The photosynthetic performance of Chlamydomonas sp. decreased in high-light-adapted cells when IC limited. In addition, the minimal phosphorus (P) cell quota was suggestive of a higher P requirement under IC limitation. Subsequently, it was shown that Chlamydomonas sp. was a mixotroph, able to enhance its growth rate by taking up dissolved organic carbon (DOC) via osmotrophy. Therefore, it could survive in deeper water strata where DOC concentrations were higher and light limited. However, neither IC limitation, P availability nor in situ DOC concentrations (bottom-up control) could fully explain the vertical distribution of Chlamydomonas sp. in Lake 111. Conversely, when a novel approach was adopted, the grazing influence of the phagotrophic phototroph, Ochromonas sp., was found to exert top-down control on its prey (Chlamydomonas sp.) reducing prey abundance in the upper water strata. This, coupled with the fact that Chlamydomonas sp. uses DOC for growth, leads to a pronounced accumulation of Chlamydomonas sp. cells at depth; an apparent DCM. Therefore, grazing appears to be the main factor influencing the

  4. Evaluation of indigenous fresh water microalga Scenedesmus obtusus for feed and fuel applications: Effect of carbon dioxide, light and nutrient sources on growth and biochemical characteristics.

    PubMed

    Sarat Chandra, T; Deepak, R S; Maneesh Kumar, M; Mukherji, S; Chauhan, V S; Sarada, R; Mudliar, S N

    2016-05-01

    Scenedesmus obtusus, a freshwater microalga, was evaluated for its growth and biochemical characteristics under various culture conditions. S. obtusus was tolerant at all tested CO2 concentrations up to 20%. Among the different nitrogen sources, urea showed enhanced biomass productivities up to 2-fold compared to control, where the nitrogen source was sodium nitrate. Light intensity and photoperiod had a significant effect on growth rate and biomass productivity. The growth rate was observed maximum under continuous light exposure at the light intensities, 30μmolm(-2)sec(-1) and 60μmolm(-2)sec(-1) The species was able to tolerate the salinity levels up to 25mM NaCl, where, the increase in the concentration of NaCl suppressed the growth. Ammonium acetate and glycine showed better growth rate and biomass productivity indicating mixotrophic ability of S. obtusus. Supplementation of acetate and bicarbonate significantly enhanced the biomass productivity. Biodiesel properties of S. obtusus cultivated at various culture conditions were estimated. PMID:26923570

  5. Evaluation of fatty acid profile and biodiesel properties of microalga Scenedesmus abundans under the influence of phosphorus, pH and light intensities.

    PubMed

    Mandotra, S K; Kumar, Pankaj; Suseela, M R; Nayaka, S; Ramteke, P W

    2016-02-01

    The present study dealt with biomass, lipid concentration, fatty acid profile and biodiesel properties of microalga Scenedesmus abundans under different phosphate concentrations, pH and light intensities, one at a time. Among different phosphate concentrations, higher biomass (770.10±11.0mg/L) and lipid concentration (176.87±4.6mg/L) were at the concentration of 60mg/L. Light intensity at 6000lux yielded higher biomass and lipid concentration of 742.0±9.7 and 243.15±9.1mg/L, respectively. The biomass (769.0±12.3mg/L) and lipid (179.47±5.5mg/L) concentration were highest at pH 8 and pH 6, respectively. All the culture treatments showed marked effect on the fatty acid profile and biodiesel properties of the extracted oil. FAME derived biodiesel properties were compared with European biodiesel standards (EN 14214), Indian biodiesel standards (IS 15607) and American biodiesel standards (ASTM D 6751-08) to assess the suitability of algal oil as biodiesel feedstock. PMID:26675046

  6. Azolla filiculoides Nitrogenase Activity Decrease Induced by Inoculation with Chlamydomonas sp.

    PubMed

    Habte, M

    1986-11-01

    Experiments were conducted to determine the influence of Chlamydomonas sp. on nitrogen fixation (C(2)H(2) --> C(2)H(4)) in Azolla filiculoides and on the nitrogen fixation and growth of free-living Anabaena azollae 2B organisms. Inoculation of azolla medium with Chlamydomonas sp. was associated with decreased nitrogenase activity in A. filiculoides and with increases in the density of a fungal population identified as Acremonium sp. Subsequent inoculation of azolla medium with this fungus was also accompanied by a significant decrease in nitrogenase activity of A. filiculoides. However, the extent of depression of nitrogenase activity was significantly higher when azolla medium was inoculated with Chlamydomonas sp. than when it was inoculated with Acremonium sp. Inoculation of nitrogen-free Stanier medium with either Acremonium sp. or Chlamydomonas sp. did not adversely affect the growth or nitrogenase activity of free-living A. azollae. Decreased nitrogenase activity in A. filiculoides is apparently related to the adverse influence of the green alga and the fungus on the macrosymbiont. The mechanisms that might be involved are discussed. PMID:16347211

  7. Azolla filiculoides Nitrogenase Activity Decrease Induced by Inoculation with Chlamydomonas sp. †

    PubMed Central

    Habte, Mitiku

    1986-01-01

    Experiments were conducted to determine the influence of Chlamydomonas sp. on nitrogen fixation (C2H2 → C2H4) in Azolla filiculoides and on the nitrogen fixation and growth of free-living Anabaena azollae 2B organisms. Inoculation of azolla medium with Chlamydomonas sp. was associated with decreased nitrogenase activity in A. filiculoides and with increases in the density of a fungal population identified as Acremonium sp. Subsequent inoculation of azolla medium with this fungus was also accompanied by a significant decrease in nitrogenase activity of A. filiculoides. However, the extent of depression of nitrogenase activity was significantly higher when azolla medium was inoculated with Chlamydomonas sp. than when it was inoculated with Acremonium sp. Inoculation of nitrogen-free Stanier medium with either Acremonium sp. or Chlamydomonas sp. did not adversely affect the growth or nitrogenase activity of free-living A. azollae. Decreased nitrogenase activity in A. filiculoides is apparently related to the adverse influence of the green alga and the fungus on the macrosymbiont. The mechanisms that might be involved are discussed. PMID:16347211

  8. Dietary lipids from marine unicellular algae enhance the amount of liver and blood omega-3 fatty acids in rats.

    PubMed

    Sukenik, A; Takahashi, H; Mokady, S

    1994-01-01

    The nutritional effect of omega-3 (omega 3) polyenoic fatty acids, originating from marine unicellular algae or from fish oil, on the liver and blood lipids was studied in weanling rats fed for 2 weeks on control or experimental diets. Isolipid experimental diets containing either 10% marine microalgae or algal lipids or fish (capelin) oil substituting part (40%) or all of the soybean oil of the control diet. The algae employed were Nannochloropsis sp. or Isochrysis galbana, which are rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), respectively. Cell disruption improved the digestibility of the Nannochloropsis biomass. Diets containing algal meal significantly reduced the relative abundance of arachidonic acid (AA) in the blood and liver lipids and caused a significant increase in the percentage of the omega 3 polyunsaturated fatty acids (PUFA). Feeding Nannochloropsis lipids resulted in a similar effect on the plasma and liver fatty acid pattern as that of a diet containing disrupted cells of Nannochloropsis biomass. In comparison, the response of the plasma and liver lipids to capelin oil was characterized by a further reduction in the abundance of AA and a significant elevation in the percentage of EPA and DHA. These differences are probably due to the variations in the fatty acid composition and not to the fact that omega 3 fatty acids are associated with different lipid classes in these lipid sources. Based on the present study, it is postulated that certain marine unicellular algae can be used as a nutritional source for omega 3 PUFA. PMID:8067689

  9. Chloroplast Phylogenomic Inference of Green Algae Relationships

    PubMed Central

    Sun, Linhua; Fang, Ling; Zhang, Zhenhua; Chang, Xin; Penny, David; Zhong, Bojian

    2016-01-01

    The green algal phylum Chlorophyta has six diverse classes, but the phylogenetic relationship of the classes within Chlorophyta remains uncertain. In order to better understand the ancient Chlorophyta evolution, we have applied a site pattern sorting method to study compositional heterogeneity and the model fit in the green algal chloroplast genomic data. We show that the fastest-evolving sites are significantly correlated with among-site compositional heterogeneity, and these sites have a much poorer fit to the evolutionary model. Our phylogenomic analyses suggest that the class Chlorophyceae is a monophyletic group, and the classes Ulvophyceae, Trebouxiophyceae and Prasinophyceae are non-monophyletic groups. Our proposed phylogenetic tree of Chlorophyta will offer new insights to investigate ancient green algae evolution, and our analytical framework will provide a useful approach for evaluating and mitigating the potential errors of phylogenomic inferences. PMID:26846729

  10. An algae-covered alligator rests warily

    NASA Technical Reports Server (NTRS)

    2000-01-01

    An algae-covered alligator keeps a wary eye open as it rests in one of the ponds at Kennedy Space Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  11. Swimming like algae: biomimetic soft artificial cilia.

    PubMed

    Sareh, Sina; Rossiter, Jonathan; Conn, Andrew; Drescher, Knut; Goldstein, Raymond

    2013-01-01

    Cilia are used effectively in a wide variety of biological systems from fluid transport to thrust generation. Here, we present the design and implementation of artificial cilia, based on a biomimetic planar actuator using soft-smart materials. This actuator is modelled on the cilia movement of the alga Volvox, and represents the cilium as a piecewise constant-curvature robotic actuator that enables the subsequent direct translation of natural articulation into a multi-segment ionic polymer metal composite actuator. It is demonstrated how the combination of optimal segmentation pattern and biologically derived per-segment driving signals reproduce natural ciliary motion. The amenability of the artificial cilia to scaling is also demonstrated through the comparison of the Reynolds number achieved with that of natural cilia. PMID:23097503

  12. Random flow induced by swimming algae

    NASA Astrophysics Data System (ADS)

    Kantsler, Vasily; Rushkin, Ilia; Goldstein, Raymond

    2010-11-01

    In this work we studied the random flow induced in a fluid by the motion of a dilute suspension of the swimming algae Volvox carteri. The fluid velocity in the suspension is a superposition of the flow fields set up by the individual organisms, which in turn have multipole contributions that decay as inverse powers of distance from the organism. Here we show that the conditions under which the central limit theorem guarantees a Gaussian probability distribution function of velocity fluctuations are satisfied when the leading force singularity is a Stokeslet. Deviations from Gaussianity are shown to arise from near-field effects. Comparison is made with the statistical properties of abiotic sedimenting suspensions. The experimental results are supplemented by extensive numerical studies.

  13. High-fidelity phototaxis in biflagellate algae

    NASA Astrophysics Data System (ADS)

    Leptos, Kyriacos; Chioccioli, Maurizio; Furlan, Silvano; Pesci, Adriana; Goldstein, Raymond

    2015-11-01

    The single-cell alga Chlamydomonas reinhardtii is a motile biflagellate that can swim towards light for its photosynthetic requirements, a behavior referred to as phototaxis. The cell responds upon light stimulation through its rudimentary eye - the eyespot - by changing the beating amplitude of its two flagella accordingly - a process called the photoresponse. All this occurs in a coordinated fashion as Chlamydomonas spins about its body axis while swimming, thus experiencing oscillating intensities of light. We use high-speed video microscopy to measure the flagellar dynamics of the photoresponse on immobilized cells and interpret the results with a mathematical model of adaptation similar to that used previously for Volvox. These results are incorporated into a model of phototactic steering to yield trajectories that are compared to those obtained by three-dimensional tracking. Implications of these results for the evolution of multicellularity in the Volvocales are discussed.

  14. Swimming like algae: biomimetic soft artificial cilia

    PubMed Central

    Sareh, Sina; Rossiter, Jonathan; Conn, Andrew; Drescher, Knut; Goldstein, Raymond E.

    2013-01-01

    Cilia are used effectively in a wide variety of biological systems from fluid transport to thrust generation. Here, we present the design and implementation of artificial cilia, based on a biomimetic planar actuator using soft-smart materials. This actuator is modelled on the cilia movement of the alga Volvox, and represents the cilium as a piecewise constant-curvature robotic actuator that enables the subsequent direct translation of natural articulation into a multi-segment ionic polymer metal composite actuator. It is demonstrated how the combination of optimal segmentation pattern and biologically derived per-segment driving signals reproduce natural ciliary motion. The amenability of the artificial cilia to scaling is also demonstrated through the comparison of the Reynolds number achieved with that of natural cilia. PMID:23097503

  15. Pseudomonas kuykendallii sp. nov.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This is a submission to the list of microorganisms with standing in nomenclature maintained by the International Journal of Systematic and Evolutionary Microbiology. We wish to have Pseudomonas kuykendallii sp. nov. added to the list as a valid species belonging to the genus Pseudomonas. Three str...

  16. Isoprenoid biosynthesis in eukaryotic phototrophs: A spotlight on algae

    SciTech Connect

    Lohr M.; Schwender J.; Polle, J. E. W.

    2012-04-01

    Isoprenoids are one of the largest groups of natural compounds and have a variety of important functions in the primary metabolism of land plants and algae. In recent years, our understanding of the numerous facets of isoprenoid metabolism in land plants has been rapidly increasing, while knowledge on the metabolic network of isoprenoids in algae still lags behind. Here, current views on the biochemistry and genetics of the core isoprenoid metabolism in land plants and in the major algal phyla are compared and some of the most pressing open questions are highlighted. Based on the different evolutionary histories of the various groups of eukaryotic phototrophs, we discuss the distribution and regulation of the mevalonate (MVA) and the methylerythritol phosphate (MEP) pathways in land plants and algae and the potential consequences of the loss of the MVA pathway in groups such as the green algae. For the prenyltransferases, serving as gatekeepers to the various branches of terpenoid biosynthesis in land plants and algae, we explore the minimal inventory necessary for the formation of primary isoprenoids and present a preliminary analysis of their occurrence and phylogeny in algae with primary and secondary plastids. The review concludes with some perspectives on genetic engineering of the isoprenoid metabolism in algae.

  17. Study on the relationship between speciation of heavy metals and their ecotoxicity. I. Toxicity of Cu, Cd, Pb and Zn in seawater to three marine algae in the presence of different complexation agents

    NASA Astrophysics Data System (ADS)

    Zhang, Manping; Wang, Juying; Bao, Junbo

    1992-09-01

    Heavy metal is a main pollutant in the marine ecosystem, so study on the effect of heavy metal on phytoplankton is important. Algae ( Chaetoceros sp., Dunaliella sp., Dicrateria zhanjiangenis Hu. var. sp.) were laboratory cultured to observe the effect of heavy metals on their growth. The effect of different metal ion concentration, the detoxication effect of complexation agents and the growth of algae in different media and different nutrition levels were studied to evaluate the effect of metal speciation. It is proved that trace amount of heavy metals can stimulate the growth of algae cells but that high concentration is lethal. The sequence of toxicity is Cd2+>Zn2+>Pb2+. In ordinary nutrition conditions, the detoxication sequence of complexation agents to Chaetoceros sp. is EDTA >sodium salicylate>sodium oxalate >sodium citrate>sulfanilic acid>O-phenanthroline. This is in good conformity with the stability constant sequence of these agents with copper and good evidence that toxicity of metal ion is related to its activity and not to its total concentration.

  18. Photophysiology and cellular composition of sea ice algae

    SciTech Connect

    Lizotte, M.P.

    1989-01-01

    The productivity of sea ice algae depends on their physiological capabilities and the environmental conditions within various microhabitats. Pack ice is the dominant form of sea ice, but the photosynthetic activity of associated algae has rarely been studied. Biomass and photosynthetic rates of ice algae of the Weddell-Scotia Sea were investigated during autumn and winter, the period when ice cover grows from its minimum to maximum. Biomass-specific photosynthetic rates typically ranged from 0.3 to 3.0 {mu}g C {center dot} {mu}g chl{sup {minus}1} {center dot} h{sup {minus}1} higher than land-fast ice algae but similar to Antarctic phytoplankton. Primary production in the pack ice during winter may be minor compared to annual phytoplankton production, but could represent a vital seasonal contribution to the Antarctic ecosystem. Nutrient supply may limit the productivity of ice algae. In McMurdo Sound, congelation ice algae appeared to be more nutrient deficient than underlying platelet ice algae based on: lower nitrogen:carbon, chlorophyll:carbon, and protein:carbohydrate; and {sup 14}C-photosynthate distribution to proteins and phospholipids was lower, while distribution to polysaccharides and neutral lipids was higher. Depletion of nitrate led to decreased nitrogen:carbon, chlorophyll:carbon, protein:carbohydrate, and {sup 14}C-photosynthate to proteins. Studied were conducted during the spring bloom; therefore, nutrient limitation may only apply to dense ice algal communities. Growth limiting conditions may be alleviated when algae are released into seawater during the seasonal recession of the ice cover. To continue growth, algae must adapt to the variable light field encountered in a mixed water column. Photoadaptation was studied in surface ice communities and in bottom ice communities.

  19. Activated chemical defenses suppress herbivory on freshwater red algae.

    PubMed

    Goodman, Keri M; Hay, Mark E

    2013-04-01

    The rapid life cycles of freshwater algae are hypothesized to suppress selection for chemical defenses against herbivores, but this notion remains untested. Investigations of chemical defenses are rare for freshwater macrophytes and absent for freshwater red algae. We used crayfish to assess the palatability of five freshwater red algae relative to a palatable green alga and a chemically defended aquatic moss. We then assessed the roles of structural, nutritional, and chemical traits in reducing palatability. Both native and non-native crayfish preferred the green alga Cladophora glomerata to four of the five red algae. Batrachospermum helminthosum, Kumanoa holtonii, and Tuomeya americana employed activated chemical defenses that suppressed feeding by 30-60 % following damage to algal tissues. Paralemanea annulata was defended by its cartilaginous structure, while Boldia erythrosiphon was palatable. Activated defenses are thought to reduce ecological costs by expressing potent defenses only when actually needed; thus, activation might be favored in freshwater red algae whose short-lived gametophytes must grow and reproduce rapidly over a brief growing season. The frequency of activated chemical defenses found here (three of five species) is 3-20× higher than for surveys of marine algae or aquatic vascular plants. If typical for freshwater red algae, this suggests that (1) their chemical defenses may go undetected if chemical activation is not considered and (2) herbivory has been an important selective force in the evolution of freshwater Rhodophyta. Investigations of defenses in freshwater rhodophytes contribute to among-system comparisons and provide insights into the generality of plant-herbivore interactions and their evolution. PMID:23011851

  20. 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