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Sample records for algae scenedesmus vacuolatus

  1. Predictive modeling studies for the ecotoxicity of ionic liquids towards the green algae Scenedesmus vacuolatus.

    PubMed

    Das, Rudra Narayan; Roy, Kunal

    2014-06-01

    Hazardous potential of ionic liquids is becoming an issue of high concern with increasing application of these compounds in various industrial processes. Predictive toxicological modeling on ionic liquids provides a rational assessment strategy and aids in developing suitable guidance for designing novel analogues. The present study attempts to explore the chemical features of ionic liquids responsible for their ecotoxicity towards the green algae Scenedesmus vacuolatus by developing mathematical models using extended topochemical atom (ETA) indices along with other categories of chemical descriptors. The entire study has been conducted with reference to the OECD guidelines for QSAR model development using predictive classification and regression modeling strategies. The best models from both the analyses showed that ecotoxicity of ionic liquids can be decreased by reducing chain length of cationic substituents and increasing hydrogen bond donor feature in cations, and replacing bulky unsaturated anions with simple saturated moiety having less lipophilic heteroatoms.

  2. S-metolachlor pulse exposure on the alga Scenedesmus vacuolatus: effects during exposure and the subsequent recovery.

    PubMed

    Vallotton, Nathalie; Moser, Daya; Eggen, Rik I L; Junghans, Marion; Chèvre, Nathalie

    2008-09-01

    In streams and creeks, the aquatic flora is exposed to fluctuating concentrations of herbicides during and following their application. Peak concentrations of herbicides, like the chloroacetanilide S-metolachlor, are usually detected following rain events. In this study, we assessed the effect of S-metolachlor pulse exposure on the algae Scenedesmus vacuolatus. We measured the time-dependency of effects during exposure on algae population and identified the algae development stage most sensitive to S-metolachlor. Furthermore, we assessed the time-to-recovery of the algae following exposure. A 6h pulse exposure at 598microgl(-1) was sufficient to inhibit cell reproduction by 50%. However, the exposure period had to coincide with the cell development stage specifically inhibited by S-metolachlor, which is the end of the cell growth phase. In algae populations composed of cells at all development stages, we initially observed an increase in the size of some algal cells, ultimately leading to an inhibition of the growth rate. In these experimental conditions, effects were observed after 18h of exposure and greatly increased with time. The recovery of algae following exposure to strongly inhibiting S-metolachlor concentrations was delayed and only occurred after 29h. These findings suggest that peak exposure to S-metolachlor may affect the growth of sensitive alga in surface waters, considering that the effects extend beyond the period of exposure. PMID:18602658

  3. Thiols in Scenedesmus vacuolatus upon exposure to metals and metalloids.

    PubMed

    Le Faucheur, Séverine; Schildknecht, Fabian; Behra, Renata; Sigg, Laura

    2006-12-30

    Phytochelatins are intracellular metal ligands produced by algae when exposed to elevated metal concentrations. In freshwater ecosystems, algae are exposed to a wide range of metals and metalloids. The aim of this study was thus to investigate phytochelatin induction in freshwater algae upon metal and metalloid exposure. To that purpose, the unicellular green alga Scenedesmus vacuolatus, was exposed to Cu, Zn, Ni, Pb and Ag, as well as to As(III), As(V), Sb(III) and Sb(V), and examined for its thiol content (gamma-glutamylcysteine, glutathione and phytochelatins). Glutathione content was found to decrease upon the exposure to Zn and to increase upon the exposure to Pb and Ag. Phytochelatins were only induced by Cu (at [Cu2+] = 8x10(-11) M) and Pb (at [Pb2+] = 8x10(-11) to 8x10(-10) M), where [Cu2+] and [Pb2+] are computed free metal ion concentrations. Glutathione content also decreased upon the exposure to Sb(V) whereas an increase was observed as a result as the exposure to As(III) and As(V). The metalloids As(III), As(V) and Sb(III) in the concentration range from 8x10(-6) to 2x10(-4) M (total concentrations of oxyanions) were inducing phytochelatins. Glutathione and phytochelatin content in S. vacuolatus do thus sensitively respond to exposure to a number of metals and metalloids.

  4. Effect of sequential isoproturon pulse exposure on Scenedesmus vacuolatus.

    PubMed

    Vallotton, Nathalie; Eggen, Rik Ilda Lambertus; Chèvre, Nathalie

    2009-04-01

    Aquatic organisms are typically exposed to fluctuating concentrations of herbicides in streams. To assess the effects on algae of repeated peak exposure to the herbicide isoproturon, we subjected the alga Scenedesmus vacuolatus to two sequential pulse exposure scenarios. Effects on growth and on the inhibition of the effective quantum yield of photosystem II (PSII) were measured. In the first scenario, algae were exposed to short, 5-h pulses at high isoproturon concentrations (400 and 1000 microg/l), each followed by a recovery period of 18 h, while the second scenario consisted of 22.5-h pulses at lower concentrations (60 and 120 microg/l), alternating with short recovery periods (1.5 h). In addition, any changes in the sensitivity of the algae to isoproturon following sequential pulses were examined by determining the growth rate-EC(50) prior to and following exposure. In both exposure scenarios, we found that algal growth and its effective quantum yield were systematically inhibited during the exposures and that these effects were reversible. Sequential pulses to isoproturon could be considered a sequence of independent events. Nevertheless, a consequence of inhibited growth during the repeated exposures is the cumulative decrease in biomass production. Furthermore, in the second scenario, when the sequence of long pulses began to approach a scenario of continuous exposure, a slight increase in the tolerance of the algae to isoproturon was observed. These findings indicated that sequential pulses do affect algae during each pulse exposure, even if algae recover between the exposures. These observations could support an improved risk assessment of fluctuating exposures to reversibly acting herbicides. PMID:18709397

  5. 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.

  6. 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.

  7. Light-driven Uptake of Oxygen, Carbon Dioxide, and Bicarbonate by the Green Alga Scenedesmus12

    PubMed Central

    Radmer, Richard; Ollinger, Otto

    1980-01-01

    Mass spectrometric techniques were used to study several aspects of the competition between O2 and species of inorganic carbon for photosynthetically generated reducing power in the green alga, Scenedesmus. In contrast to wild type, no appreciable light-driven O2 uptake was observed in a mutant lacking photosystem I. It is concluded that the carbon cycle-independent reduction of O2 occurs at the expense of photosystem I-generated reducing equivalents. The commonly observed differences between CO2-grown and air-grown Scenedesmus with respect to CO2 uptake and glycolate formation cannot be ascribed to differences in their capacity for light-driven O2 uptake. There were no intrinsic differences found in O2 uptake capacity between the two physiological types under conditions in which CO2 was saturating or CO2 uptake was inhibited. It was only under CO2-limited conditions that pronounced differences between the two physiological types were observed. This fact suggests that differences in O2 metabolism and sensitivity between the two types really reflect differences in their capacity to assimilate inorganic carbon; in this respect they are analogous to C3 and C4 plants. The hypothesis that air-grown Scenedesmus can assimilate HCO3− by directly monitoring the time course of dissolved CO2, O2 uptake, and O2 evolution in illuminated algal suspensions at alkaline pH was tested. Inasmuch as the measuring technique employed was fast compared to the nonenzymic equilibration of the inorganic carbon species, it was possible to determine the degree to which the CO2 concentration deviated from equilibrium (with the other inorganic carbon species) during the course of illumination. The observed kinetics in air-grown and CO2-grown algae in the presence and absence of carbonic anhydrase, and a comparison of these kinetics with theoretical (computer-generated) time courses, support the idea that air-adapted algae are able to assimilate HCO3− actively at a high rate. The data

  8. 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

    2015-04-14

    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.

  9. 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

  10. 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

  11. 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.

  12. 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

  13. Acute toxicity of butachlor and atrazine to freshwater green alga Scenedesmus obliquus and cladoceran Daphnia carinata.

    PubMed

    He, Hongzhi; Yu, Jing; Chen, Guikui; Li, Wenyang; He, Jinbo; Li, Huashou

    2012-06-01

    Both single and joint toxicity of atrazine and butachlor to freshwater green alga Scenedesmus obliquus and cladoceran Daphnia carinata isolated from South China were investigated in the present study. The 96 h-EC(50) values of atrazine and butachlor to S. obliquus were 0.0147 and 2.31 mg L(-1), while the 48 h-LC(50) values to D. carinata were 60.6 and 3.40 mg L(-1), respectively. These results suggest that atrazine could be highly toxic to S. obliquus and slightly toxic to D. carinata, while butachlor exhibits moderate toxicity to both organisms. The additive indexes of atrazine and butachlor mixtures were -2.68 (-3.02 to -2.32) to S. obliquus and 0.054 (-0.025 to 0.238) to D. carinata, respectively. Therefore, the joint action of two herbicides was significant antagonism to S. obliquus, while significant synergism was not shown to D. carinata. Moreover, significant linear correlation between the natural logarithm of herbicide concentrations and growth rates of alga S. obliquus was observed. Taken together, it is the first study reporting the toxicity endpoints for mixture of atrazine and butachlor against S. obliquus and D. carinata isolated from south China. The present results would be helpful to provide data to assess the ecological risk of both herbicides to aquatic organisms.

  14. 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

  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.

  16. Ammonia removal from anaerobic digestion effluent of livestock waste using green alga Scenedesmus sp.

    PubMed

    Park, Jongmin; Jin, Hai-Feng; Lim, Byung-Ran; Park, Ki-Young; Lee, Kisay

    2010-11-01

    The green alga Scenedesmus was investigated for its ability to remove nitrogen from anaerobic digestion effluent possessing high ammonium content and alkalinity in addition to its growth characteristics. Nitrate and ammonium were indistinguishable as a nitrogen source when the ammonium concentration was at normal cultivation levels. Ammonium up to 100ppm NH(4)-N did not inhibit cell growth, but did decrease final cell density by up to 70% at a concentration of 200-500ppm NH(4)-N. Inorganic carbon of alkalinity in the form of bicarbonate was consumed rapidly, in turn causing the attenuation of cell growth. Therefore, maintaining a certain level of inorganic carbon is necessary in order to prolong ammonia removal. A moderate degree of aeration was beneficial to ammonia removal, not only due to the stripping of ammonium to ammonia gas but also due to the stripping of oxygen, which is an inhibitor of regular photosynthesis. Magnesium is easily consumed compared to other metallic components and therefore requires periodic supplementation. Maintaining appropriate levels of alkalinity, Mg, aeration along with optimal an initial NH(4)(+)/cell ratio were all necessary for long-term semi-continuous ammonium removal and cell growth. PMID:20663665

  17. 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

  18. 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.

  19. On the way to cyanobacterial blooms: impact of the herbicide metribuzin on the competition between a green alga (Scenedesmus) and a cyanobacterium (Microcystis).

    PubMed

    Lürling, Miquel; Roessink, Ivo

    2006-10-01

    The hypothesis that exposure to a common and widely applied photosynthesis-inhibiting herbicide, metribuzin, would alter the outcome of the competitive battle between susceptible green algae (Scenedesmus obliquus) and tolerant cyanobacteria (Microcystis aeruginosa) was tested. In a long-term (17 d) experiment, Scenedesmus and Microcystis populations as well as mixtures that started with different inoculum composition (i.e. 3:1, 1:1 and 1:3 Scenedesmus:Microcystis) were grown in the absence or presence of metribuzin (100 microg l-1). In the absence of metribuzin, Scenedesmus was competitively superior and out-competed Microcystis regardless the initial composition of the mixed communities. However, this competitive outcome was reversed completely in the presence of metribuzin, where despite growth inhibition Microcystis became dominant. Hence, photosynthesis-inhibiting herbicides may not only affect algal community structure, but also provide cyanobacteria founder populations a window for dominance and thus play an important role in promoting cyanobacteria blooms.

  20. On the way to cyanobacterial blooms: impact of the herbicide metribuzin on the competition between a green alga (Scenedesmus) and a cyanobacterium (Microcystis).

    PubMed

    Lürling, Miquel; Roessink, Ivo

    2006-10-01

    The hypothesis that exposure to a common and widely applied photosynthesis-inhibiting herbicide, metribuzin, would alter the outcome of the competitive battle between susceptible green algae (Scenedesmus obliquus) and tolerant cyanobacteria (Microcystis aeruginosa) was tested. In a long-term (17 d) experiment, Scenedesmus and Microcystis populations as well as mixtures that started with different inoculum composition (i.e. 3:1, 1:1 and 1:3 Scenedesmus:Microcystis) were grown in the absence or presence of metribuzin (100 microg l-1). In the absence of metribuzin, Scenedesmus was competitively superior and out-competed Microcystis regardless the initial composition of the mixed communities. However, this competitive outcome was reversed completely in the presence of metribuzin, where despite growth inhibition Microcystis became dominant. Hence, photosynthesis-inhibiting herbicides may not only affect algal community structure, but also provide cyanobacteria founder populations a window for dominance and thus play an important role in promoting cyanobacteria blooms. PMID:16540149

  1. [Experimental assessment of combined effect of nitrates and acute gamma-irradiation on green algae Scenedesmus quadricauda growth].

    PubMed

    Triapitsyna, G A; Tarasova, S P; Atamaniuk, N I; Osipov, D I; Priakhin, E A

    2012-01-01

    The combined effect of acute gamma-irradiation at doses of 0, 50, 100, 150 and 200 Gy and nitrates in concentrations of 0.04 g/dm3 (that corresponds to maximum permissible concentrations for fishery waters), 0.1, 0.25, 0.5, 1.0, 2.5 g/dm3 (that is close to NO3(-) level in water of a reservoir R-17 used as radioactive waste storage of the "Mayak" Production Association) and 5.0 g/dm3 (that is close to NO3(-) level in the water of radioactive waste storage reservoir R-9) on the unicellular green algae Scenedesmus quadricauda growth has been studied in laboratory conditions. It was shown that the joint effects of nitrates and y-radiation had an antagonistic character. Thus, it may be concluded that chemical pollution is the factor limiting the development of green algae in reservoir R-17; probably, both factors, chemical and radiating, are essential to the algocenosis degradation in reservoir R-9. PMID:22891554

  2. [Experimental assessment of combined effect of nitrates and acute gamma-irradiation on green algae Scenedesmus quadricauda growth].

    PubMed

    Triapitsyna, G A; Tarasova, S P; Atamaniuk, N I; Osipov, D I; Priakhin, E A

    2012-01-01

    The combined effect of acute gamma-irradiation at doses of 0, 50, 100, 150 and 200 Gy and nitrates in concentrations of 0.04 g/dm3 (that corresponds to maximum permissible concentrations for fishery waters), 0.1, 0.25, 0.5, 1.0, 2.5 g/dm3 (that is close to NO3(-) level in water of a reservoir R-17 used as radioactive waste storage of the "Mayak" Production Association) and 5.0 g/dm3 (that is close to NO3(-) level in the water of radioactive waste storage reservoir R-9) on the unicellular green algae Scenedesmus quadricauda growth has been studied in laboratory conditions. It was shown that the joint effects of nitrates and y-radiation had an antagonistic character. Thus, it may be concluded that chemical pollution is the factor limiting the development of green algae in reservoir R-17; probably, both factors, chemical and radiating, are essential to the algocenosis degradation in reservoir R-9.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Influence of the CO2 absorbent monoethanolamine on growth and carbon fixation by the green alga Scenedesmus sp.

    PubMed

    Choi, Wookjin; Kim, Garam; Lee, Kisay

    2012-09-01

    The influence of monoethanolamine (MEA) as a CO(2) absorbent on photoautotrophic culture of CO(2)-fixing microalgae was investigated. When 300 ppm MEA (4.92 mM) was added to blank culture medium, the dissolved inorganic carbon and the molar absorption ratio increased to 51.0mg/L and 0.34 mol CO2 = mol MEA, respectively, which was an almost 6-fold increase in CO(2) solubility. When free MEA up to 300 mg/L was added to a green alga Scenedesmus sp. culture that was supplied 5% (v/v) CO(2) at 0.1 vvm, both cell growth rate and final cell density were enhanced compared to when no MEA was added. The cell growth rate reached 288.6 mg/L/d, which was equivalent to 539.6 mg-CO(2)/L/d as a CO(2)-fixation rate and enhancement of about 63.0% compared to not adding MEA. Chlorophyll-a content and nitrate consumption rate increased correspondingly. MEA doses higher than 400mg/L inhibited cell growth, probably due to toxicity of the carbamate intermediate.

  8. 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

  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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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

  16. Enhancement of biodiesel production from marine alga, Scenedesmus sp. through in situ transesterification process associated with acidic catalyst.

    PubMed

    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.

  17. The green alga Scenedesmus obliquus contains both diadenosine 5',5'''-P1,P4-tetraphosphate (asymmetrical) pyrophosphohydrolase and phosphorylase activities.

    PubMed Central

    McLennan, A G; Mayers, E; Hankin, S; Thorne, N M; Prescott, M; Powls, R

    1994-01-01

    Diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) phosphorylase and Ap4A pyrophosphohydrolase activities have been purified from extracts of the green alga Scenedesmus obliquus. Both activities were also detected in Scenedesmus brasiliensis, Scenedesmus quadricauda and in Chlorella vulgaris. This is the first time that both types of enzyme have been detected in the same species. The Ap4A phosphorylase has a molecular mass of 46-48 kDa, a broad pH optimum between 7.5 and 9.5, and requires a divalent ion for activity (Mg2+ > Co2+ > Ca2+ = Mn2+ = Cd2+ > Zn2+). It degrades substrates with at least four phosphate groups and always produces a nucleoside 5'-diphosphate product. The Km values for Ap4A and Pi are 5.3 microM and 160 microM, respectively, and kcat. = 1.8 s-1. Arsenate, vanadate, molybdate, chromate and tungstate can substitute for phosphate. The enzyme also catalyses Ap4A synthesis (Keq. = [Ap4A] [Pi]/[ATP][ADP] = 9 x 10(-4)) and ADP arsenolysis. The Ap4A hydrolase has a molecular mass of 26-28 kDa, an alkaline pH optimum of 8.8-9.8, and prefers Zn2+ as the stimulatory ion (Zn2+ > Mg2+ > Mn2+ > Co2+ > Cd2+). It degrades substrates with at least four phosphate groups, having a slight preference for Ap5A, and always produces a nucleoside 5'-triphosphate product. The Km value for Ap4A is 6.6 microM and kcat. = 1.3 s-1. It is inhibited competitively by adenosine 5'-tetraphosphate (Ki = 0.67 microM) and non-competitively by fluoride (Ki = 150 microM). A 50-54 kDa dinucleoside 5',5'''-P1,P3-triphosphate (Ap3A) pyrophosphohydrolase was also detected in S. obliquus, S. quadricauda and C. vulgaris. The corresponding enzyme in S. brasiliensis (> 100 kDa) may be a dimer Images Figure 2 PMID:8198532

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. [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.

  5. Cytotoxicity of ZnO NPs towards fresh water algae Scenedesmus obliquus at low exposure concentrations in UV-C, visible and dark conditions.

    PubMed

    Bhuvaneshwari, M; Iswarya, V; Archanaa, S; Madhu, G M; Kumar, G K Suraish; Nagarajan, R; Chandrasekaran, N; Mukherjee, Amitava

    2015-05-01

    Continuous increase in the usage of ZnO nanoparticles in commercial products has exacerbated the risk of release of these particles into the aquatic environment with possible harmful effects on the biota. In the current study, cytotoxic effects of two types of ZnO nanoparticles, having different initial effective diameters in filtered and sterilized lake water medium [487.5±2.55 nm for ZnO-1 NPs and 616.2±38.5 nm for ZnO-2 NPs] were evaluated towards a dominant freshwater algal isolate Scenedesmus obliquus in UV-C, visible and dark conditions at three exposure concentrations: 0.25, 0.5 and 1 mg/L. The toxic effects were found to be strongly dependent on the initial hydrodynamic particle size in the medium, the exposure concentrations and the irradiation conditions. The loss in viability, LDH release and ROS generation were significantly enhanced in the case of the smaller sized ZnO-1 NPs than in the case of ZnO-2 NPs under comparable test conditions. The toxicity of both types of ZnO NPs was considerably elevated under UV-C irradiation in comparison to that in dark and visible light conditions, the effects being more enhanced in case of ZnO-1 NPs. The size dependent dissolution of the ZnO NPs in the test medium and possible toxicity due to the released Zn(2+) ions was also noted. The surface adsorption of the nanoparticles was substantiated by scanning electron microscopy. The internalization/uptake of the NPs by the algal cells was confirmed by fluorescence microscopy, transmission electron microscopy, and elemental analyses.

  6. 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.

  7. Effect-directed analysis of contaminated sediments with partition-based dosing using green algae cell multiplication inhibition.

    PubMed

    Bandow, Nicole; Altenburger, Rolf; Streck, Georg; Brack, Werner

    2009-10-01

    Effect-directed analysis (EDA) has been frequently and successfully used to identify key toxicants in sediment extracts. However, by disregarding bioavailability this approach may lead to a biased prioritisation of fractions and toxicants with respect to hazards and risks. To overcome this problem the present EDA of sediment components from the Bílina river (Most Czech Republic), that inhibit growth of the green algae Scenedesmus vacuolatus, applies a novel partition-based dosing technique to prioritize and identify major toxic fractions and compounds in comparison to conventional solvent dosing. The novel dosing technique is based on partitioning from loaded silicone rods to the aqueous phase similar to partition processes that determine exposure in native sediment-water systems. In the present study the application of partition-based dosing had a big influence suggesting polar compounds such as triclosan as key toxicants while polycyclic aromatic hydrocarbon (PAH) fractions did not exhibit significant effects. In contrast, conventional dosing prioritized mainly PAHs in agreement with previous studies. For both approaches individual toxicants could be confirmed quantitatively based on the index of confirmation quality (ICQ), which compares the effect of fractions and artificial mixtures of identified and quantified toxicants over the full range of effect levels. PMID:19848144

  8. 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

  9. 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.

  10. QSAR analysis and specific endpoints for classifying the physiological modes of action of biocides in synchronous green algae.

    PubMed

    Neuwoehner, Judith; Junghans, Marion; Koller, Mirjam; Escher, Beate I

    2008-10-20

    We propose the use of additional physiological endpoints in the 24h growth inhibition test with synchronous cultures of Scenedesmus vacuolatus for the classification of physiological modes of toxic action of chemicals in green algae. The classification scheme is illustrated on the example of one baseline toxicant (3-nitroaniline) and five biocides (irgarol, diuron, Sea-Nine, tributyltin (TBT) and norflurazon). The well-established endpoint of inhibition of reproduction is used for an analysis of the degree of specificity of toxicity by comparing the experimental data with predictions from a quantitative structure-activity relationship (QSAR) for baseline toxicity (narcosis). For those compounds with a toxic ratio greater than 10, i.e. a 10 times higher effect in reproduction than predicted by baseline toxicity, additionally the physiological endpoints inhibition of photosynthesis, cell division and cell volume growth were experimentally assessed. Depending on the relative sensitivity of the different endpoints the chemicals were classified into five different classes of modes of toxic action using a flow chart that was developed in the present study. The advantage of the novel classification scheme is the simplicity of the experimental approach. For the determination of the inhibition of reproduction, the cell size and numbers are quantified with a particle analyzer. This information can be used to derive also the physiological endpoints of cell volume growth and inhibition of cell division. The only additional measurement is the inhibition of the photosynthesis efficiency, which can be easily performed using the non-invasive saturation pulse method and pulse-modulated chlorophyll fluorometry with the Tox-Y-PAM instrument. This mechanistic approach offers a great future potential in ecotoxicology for the physiological mode of action classification of chemicals in algae, which should be a crucial step considered in the risk assessment of chemicals.

  11. QSAR analysis and specific endpoints for classifying the physiological modes of action of biocides in synchronous green algae.

    PubMed

    Neuwoehner, Judith; Junghans, Marion; Koller, Mirjam; Escher, Beate I

    2008-10-20

    We propose the use of additional physiological endpoints in the 24h growth inhibition test with synchronous cultures of Scenedesmus vacuolatus for the classification of physiological modes of toxic action of chemicals in green algae. The classification scheme is illustrated on the example of one baseline toxicant (3-nitroaniline) and five biocides (irgarol, diuron, Sea-Nine, tributyltin (TBT) and norflurazon). The well-established endpoint of inhibition of reproduction is used for an analysis of the degree of specificity of toxicity by comparing the experimental data with predictions from a quantitative structure-activity relationship (QSAR) for baseline toxicity (narcosis). For those compounds with a toxic ratio greater than 10, i.e. a 10 times higher effect in reproduction than predicted by baseline toxicity, additionally the physiological endpoints inhibition of photosynthesis, cell division and cell volume growth were experimentally assessed. Depending on the relative sensitivity of the different endpoints the chemicals were classified into five different classes of modes of toxic action using a flow chart that was developed in the present study. The advantage of the novel classification scheme is the simplicity of the experimental approach. For the determination of the inhibition of reproduction, the cell size and numbers are quantified with a particle analyzer. This information can be used to derive also the physiological endpoints of cell volume growth and inhibition of cell division. The only additional measurement is the inhibition of the photosynthesis efficiency, which can be easily performed using the non-invasive saturation pulse method and pulse-modulated chlorophyll fluorometry with the Tox-Y-PAM instrument. This mechanistic approach offers a great future potential in ecotoxicology for the physiological mode of action classification of chemicals in algae, which should be a crucial step considered in the risk assessment of chemicals. PMID:18789546

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. Interspecies quantitative structure-toxicity-toxicity (QSTTR) relationship modeling of ionic liquids. Toxicity of ionic liquids to V. fischeri, D. magna and S. vacuolatus.

    PubMed

    Das, Rudra Narayan; Roy, Kunal; Popelier, Paul L A

    2015-12-01

    Considering the increasing uses of ionic liquids (ILs) in various industrial processes and chemical engineering operations, a complete assessment of their hazardous profile is essential. In the absence of adequate experimental data, in silico modeling might be helpful in filling data gaps for the toxicity of ILs towards various ecological indicator organisms. Using the rationale of taxonomic relatedness, the development of predictive quantitative structure-toxicity-toxicity relationship (QSTTR) models allows predicting the toxicity of ILs to a particular species using available experimental toxicity data towards a different species. Such studies may employ, along with the available experimental toxicity data to a species, molecular structure features and physicochemical properties of chemicals as independent variables for prediction of the toxicity profile against another closely related species. A few such interspecies toxicity correlation models have been reported in the literature for diverse chemicals in general, but this approach has been rarely applied to the class of ionic liquids. The present study involves the use of IL toxicity data towards the bacteria Vibrio fischeri along with molecular structure derived information or computational descriptors like extended topochemical atom (ETA) indices, quantum topological molecular similarity (QTMS) descriptors and computed lipophilicity measure (logk0) for the interspecies exploration of the toxicity data towards green algae S. vacuolatus and crustacea Daphnia magna, separately. This modeling study has been performed in accordance with the OECD guidelines. Finally, predictions for a true external set have been performed to fill the data gap of toxicity towards daphnids and algae using the Vibrio toxicity data and molecular structure attributes. PMID:26414597

  17. Interspecies quantitative structure-toxicity-toxicity (QSTTR) relationship modeling of ionic liquids. Toxicity of ionic liquids to V. fischeri, D. magna and S. vacuolatus.

    PubMed

    Das, Rudra Narayan; Roy, Kunal; Popelier, Paul L A

    2015-12-01

    Considering the increasing uses of ionic liquids (ILs) in various industrial processes and chemical engineering operations, a complete assessment of their hazardous profile is essential. In the absence of adequate experimental data, in silico modeling might be helpful in filling data gaps for the toxicity of ILs towards various ecological indicator organisms. Using the rationale of taxonomic relatedness, the development of predictive quantitative structure-toxicity-toxicity relationship (QSTTR) models allows predicting the toxicity of ILs to a particular species using available experimental toxicity data towards a different species. Such studies may employ, along with the available experimental toxicity data to a species, molecular structure features and physicochemical properties of chemicals as independent variables for prediction of the toxicity profile against another closely related species. A few such interspecies toxicity correlation models have been reported in the literature for diverse chemicals in general, but this approach has been rarely applied to the class of ionic liquids. The present study involves the use of IL toxicity data towards the bacteria Vibrio fischeri along with molecular structure derived information or computational descriptors like extended topochemical atom (ETA) indices, quantum topological molecular similarity (QTMS) descriptors and computed lipophilicity measure (logk0) for the interspecies exploration of the toxicity data towards green algae S. vacuolatus and crustacea Daphnia magna, separately. This modeling study has been performed in accordance with the OECD guidelines. Finally, predictions for a true external set have been performed to fill the data gap of toxicity towards daphnids and algae using the Vibrio toxicity data and molecular structure attributes.

  18. Harvesting of Scenedesmus obliquus FSP-3 using dispersed ozone flotation.

    PubMed

    Cheng, Ya-Ling; Juang, Yu-Chuan; Liao, Guan-Yu; Tsai, Pei-Wen; Ho, Shih-Hsin; Yeh, Kuei-Ling; Chen, Chun-Yen; Chang, Jo-Shu; Liu, Jhy-Chern; Chen, Wen-Ming; Lee, Duu-Jong

    2011-01-01

    The Scenedesmus obliquus FSP-3, a species with excellent potential for CO(2) capture and lipid production, was harvested using dispersed ozone flotation. While air aeration does not, ozone produces effective solid-liquid separation through flotation. Ozone dose applied for sufficient algal flotation is similar to those used in practical drinking waterworks. The algae removal rate, surface charge, and hydrophobicity of algal cells, and fluorescence characteristics and proteins and polysaccharides contents of algogenic organic matter (AOM) were determined during ozonation. Proteins released from tightly bound AOM are essential to modifying the hydrophobicity of bubble surfaces for easy cell attachment and to forming a top froth layer for collecting floating cells. Humic substances in the suspension scavenge dosed ozone that adversely affects ozone flotation efficiency of algal cells.

  19. Nitrate and phosphate removal by chitosan immobilized Scenedesmus.

    PubMed

    Fierro, Sashenka; Sánchez-Saavedra, Maria del Pilar; Copalcúa, Carmen

    2008-03-01

    The effect of chitosan immobilization of Scenedesmus spp. cells on its viability, growth and nitrate and phosphate uptake was investigated. Scenedesmus sp. (strains 1 and 2) and Scenedesmus obliquus immobilized in chitosan beads showed high viability after the immobilization process. Immobilized Scenedesmus sp. strain 1 had a higher growth rate than its free living counterpart. Nitrate and phosphate uptake by immobilized cells of Scenedesmus sp. (strain 1), freely suspended cells and blank chitosan beads (without cells) were evaluated. Immobilized cells accomplished a 70% nitrate and 94% phosphate removal within 12h of incubation while free-living cells removed 20% nitrate and 30% phosphate within 36 h of treatment. Blank chitosan beads were responsible for up to 20% nitrate and 60% phosphate uptake at the end of the experiment. Chitosan is a suitable matrix for immobilization of microalgae, particularly Scenedesmus sp., but this system should be improved before its application for water quality control.

  20. 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.

  1. 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

  2. [Allelopathic effect of Nelumbo nucifera stem and leaf tissue extract on the growth of Microcystis aeruginosa and Scenedesmus quadricanda].

    PubMed

    He, Lian-Sheng; Meng, Fan-Li; Diao, Xiao-Jun; Li, Yi-Wei; Meng, Rui; Xi, Bei-Dou; Shu, Jian-Min

    2013-07-01

    Effects of Nelumbo nucifera stem and leaf tissue extract on the growth of Microcystis aeruginosa and Scenedesmus quadricanda were studied to verify its potential in entriphication control. Five concentrations of Nelumbo nucifera stem and leaf tissue extract were chosen to compare their inhibitory effects on the growth of Microcystis aeruginosa and Scenedesmus quadricanda. The result showed that the leaf extract inhibited the algae bloom more effectively than the stem extract on the whole. When the leaf extract normality was 25 g x L(-1), the highest inhibition rate of Microcystis aeruginosa and Scenedesmus quadricanda was 71.33% and 78.14%, respectively, while for the stem extract, the values were 49.78% and 52.14%. Propanamide was found in both the stem and leaf tissue extracts of Nelumbo nucifera by GC-MS analysis, with concentrations of 1.1 mg x L(-1) and 0.2 mg x L(-1), respectively. The EC50 values of the two kinds of algae were calculated by the probability method. PMID:24027993

  3. 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.

  4. Ecotoxicological effects of perfluorooctanoic acid on freshwater microalgae Chlamydomonas reinhardtii and Scenedesmus obliquus.

    PubMed

    Hu, Changwei; Luo, Qi; Huang, Qingguo

    2014-05-01

    As a persistent bioaccumulative compound, perfluorooctanoic acid (PFOA) is found in various ecosystems and receives growing attention. The acute toxicity of PFOA was tested on 2 freshwater microalgae, Chlamydomonas reinhardtii and Scenedesmus obliquus. The 96-h concentration for 50% of maximal effect (EC50) values were measured, physiological responses of the algae were investigated, and uptake of PFOA by the algae was quantified. The EC50 values for C. reinhardtii and S. obliquus were 51.9 ± 1.0 mg/L and 44.0 ± 1.5 mg/L PFOA, respectively. After 8-d exposure to PFOA ranging from 10 mg/L to 40 mg/L, the growth of C. reinhardtii was significantly inhibited, whereas that of S. obliquus was only slightly suppressed. Increases in malonaldehyde and proline levels were observed in the 2 algae when exposed to PFOA at certain concentrations, for instance, 20 mg/L and 40 mg/L, which is indicative of the trigger of a defensive mechanism. The percentage of PFOA that was adsorbed by the algae after 8-d exposure at a dosage between 5 mg/L and 20 mg/L ranged from 5.5% to 7.5%, and the uptake of PFOA by the algae exceeded 10%. PMID:24464740

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

    PubMed

    Singh, A K; Singh, M P

    2014-12-24

    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.

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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.

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

    PubMed

    Oukarroum, Abdallah

    2016-06-01

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

  14. 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

  15. Biodiversity of algae and protozoa in a natural waste stabilization pond: a field study.

    PubMed

    Tharavathi, N C; Hosetti, B B

    2003-04-01

    A field study was carried out on the biodiversity of protozoa and algae from a natural waste stabilization pond during November, 1996 to April, 1997. The raw waste and pond samples were analysed for physico-chemical and biological parameters. High dissolved oxygen (DO) coinciding with phytoplankton peak was recorded. The algae--Chlorella vulgaris, Scenedesmus acuminatus, Oscillatoria brevis and Nostoc piscinale and Protozoa--Paramecium caudatum, Acanthamoeba sp., Bodo saltans and Oikomonas termo were obvious as dominant species, whereas algae Ochromonas pyriformis and Synura uvella and protozoa, Didinium masutum and Stentor coerulus were noted as rare species. Totally 71 species of algae and 13 species of protozoa were identified. PMID:12974463

  16. Biodiversity of algae and protozoa in a natural waste stabilization pond: a field study.

    PubMed

    Tharavathi, N C; Hosetti, B B

    2003-04-01

    A field study was carried out on the biodiversity of protozoa and algae from a natural waste stabilization pond during November, 1996 to April, 1997. The raw waste and pond samples were analysed for physico-chemical and biological parameters. High dissolved oxygen (DO) coinciding with phytoplankton peak was recorded. The algae--Chlorella vulgaris, Scenedesmus acuminatus, Oscillatoria brevis and Nostoc piscinale and Protozoa--Paramecium caudatum, Acanthamoeba sp., Bodo saltans and Oikomonas termo were obvious as dominant species, whereas algae Ochromonas pyriformis and Synura uvella and protozoa, Didinium masutum and Stentor coerulus were noted as rare species. Totally 71 species of algae and 13 species of protozoa were identified.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. Toxicity of surfactants to green microalgae Pseudokirchneriella subcapitata and Scenedesmus subspicatus and to marine diatoms Phaeodactylum tricornutum and Skeletonema costatum.

    PubMed

    Pavlić, Zelimira; Vidaković-Cifrek, Zeljka; Puntarić, Dinko

    2005-12-01

    Ecotoxicity of different commercial surfactants (six anionic, two amphoteric and one nonionic), essential constituents of cleansing hair products (shampoos), as well as ecotoxicity of eight shampoos containing different combinations of these surfactants, were tested in order to evaluate their possible toxic effects on microalgae. Specific objective of this research was to compare the sensitivity of selected freshwater and marine microalgae to these widely used surfactants and well-known pollutants in surface waters. Internationally validated methods (ISO standards) for the determination of toxic effects on the growth of planktonic freshwater green algae Pseudokirchneriella subcapitata and Scenedesmus subspicatus and marine diatoms Skeletonema costatum and Phaeodactylum tricornutum, were used. The obtained results showed that the concentrations of tested surfactants and shampoos, which resulted in 50% growth reduction of planktonic freshwater green algae, when compared to the controls without test substances (EC50), were in the range from 0.32 to 4.4 mg l(-1) for surfactants and from 2.1 to 8.5 mg l(-1) for shampoos expressed as active substance. Marine diatoms were significantly more sensitive to the tested surfactants than freshwater green algae (EC50 0.14-1.7 mg l(-1) for surfactants and 0.35-1.25 mg l(-1) for shampoos). According to the classification on the basis of environmental effects, the obtained results suggested that all tested surfactants can be classified as having toxic effects on freshwater green alga Pseudokirchneriella subcapitata. Some of them indicated that they have a very toxic effect on Scenedesmus subspicatus and marine diatoms Skeletonema costatum and Phaeodactylum tricornutum.

  2. Larvicidal algae.

    PubMed

    Marten, Gerald G

    2007-01-01

    Although most algae are nutritious food for mosquito larvae, some species kill the larvae when ingested in large quantities. Cyanobacteria (blue-green algae) that kill larvae do so by virtue of toxicity. While blue-green algae toxins may offer possibilities for delivery as larvicides, the toxicity of live blue-green algae does not seem consistent enough for live algae to be useful for mosquito control. Certain species of green algae in the order Chlorococcales kill larvae primarily because they are indigestible. Where these algae are abundant in nature, larvae consume them to the exclusion of other food and then starve. Under the right circumstances, it is possible to introduce indigestible algae into a breeding habitat so they become abundant enough to render it unsuitable for mosquito production. The algae can persist for years, even if the habitat dries periodically. The main limitation of indigestible algae lies in the fact that, under certain conditions, they may not replace all the nutritious algae in the habitat. More research on techniques to ensure complete replacement will be necessary before indigestible algae can go into operational use for mosquito control.

  3. Removal of uranyl ions from residual waters using some algae types

    NASA Astrophysics Data System (ADS)

    Cecal, Al; Palamaru, I.; Humelnicu, D.; Popa, K.; Salaru, V. V.; Rudic, V.; Gulea, A.

    1999-01-01

    This paper deals with a study on the bioaccumulation of uranyl ions resulted from residual effluents by means of some microbiological collectors: Scenedesmus quadricauda, Anabaena karakumica, Calothrix brevissima, Penicillinium sp, as well as the Glucide extract of Porphyridium cruentum, under various experimental conditions. The retaining degree of the bioaccumulated uranyl ions, as well as the leaching degree, in HCl and H2O media, of the same ions previously retained on algae were established. The retaining degree decreases in the serie: Scenedesmus quadricauda >Anabaena karakumica >Penicillinium sp>Calothrix brevissima. The leaching effect of bioaccumulated uranyl ions is higher in hydrochloric acid than in water.

  4. 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).

  5. Enantioselective toxicity and degradation of the chiral insecticide fipronil in Scenedesmus obliguus suspension system.

    PubMed

    Qu, Han; Ma, Rui-Xue; Liu, Dong-Hui; Wang, Peng; Huang, Le-Dan; Qiu, Xing-Xu; Zhou, Zhi-Qiang

    2014-11-01

    Fipronil is an effective insecticide, but it presents highly toxic effects in nontarget aquatic organisms. The present study examined the enantioselective toxicity and degradation of fipronil enantiomers in a freshwater algae Scenedesmus obliguus suspension. There was a substantial difference in the acute toxicity of the enantiomers to S. obliguus, with 72-h median effective concentrations (EC50s) of 0.29 mg L(-1) and 1.50 mg L(-1) for the R-fipronil and S-fipronil, respectively. The influences on the concentration of chlorophyll a, chlorophyll b, and carotenoids were determined, and the effects of fipronil on the concentration of chlorophyll a and chlorophyll b were also enantioselective. The degradation of fipronil in algae suspension was enantioselective, with half-lives for R-fipronil and S-fipronil of 2.9 d and 3.2 d, respectively, and the enantiomer fraction reaching 0.65 at the day 17. The enantiomeric differences should be taken into consideration for fipronil risk assessment. PMID:25077813

  6. 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

  7. 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

  8. 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.

  9. The Study of Algae

    ERIC Educational Resources Information Center

    Rushforth, Samuel R.

    1977-01-01

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

  10. 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

  11. [An experimental study and a mathematical model of interactions in mixed culture of invertebrates and algae in the "producer-consumer" aquatic biotic cycle].

    PubMed

    Pis'man, T I; Bogdanova, O N

    2004-01-01

    An experimental investigation was carried out, and a mathematical model of interaction between invertebrates (infusoria Paramecium caudatum and rotifera Brachionus plicatilis) and algae (Chlorella vulgaris and Scenedesmus quadricauda) in the "producer-consumer" aquatic biotic cycle with spatially divided links was constructed. The model describes the dynamics of a mixed culture of infusoria and rotifera in the "consumer" link, when they consume a mixed culture of algae coming from the "producer" link. A negative influence of products of algae Scenedesmus metabolism upon the reproduction of infusoria P. caudatum was revealed. Taking this into account, a qualitative coincidence of the results of mathematical modeling with experimental data was obtained. It was shown that the co-existence of mixed algae culture in the "producer" link with invertebrates in the "consumer" link in the "producer-consumer" aquatic biotic cycle is impossible because of the displacement of infusoria P. caudatum by rotifera Brachionus plicatilis. PMID:15612555

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. Enantioselective toxicity of metolachlor to Scenedesmus obliquus in the presence of cyclodextrins.

    PubMed

    Liu, Hui J; Cai, Wei D; Huang, Ruo N; Xia, Hui L; Wen, Yue Z

    2012-02-01

    Cyclodextrins (CDs) possess a variety of chiral centers and are capable of recognizing enantiomeric molecules through the formation of inclusion complexes. Two types of CDs, α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD), were selected to evaluate the effects of the enantioselective ecotoxicity of racemic metolachlor (Rac-metolachlor) and its S-enantiomer (S-metolachlor) on the freshwater algae Scenedesmus obliquus (S. obliquus) by acute toxicity test. The results showed that the aquatic toxicity of S-metolachlor was higher than Rac-metolachlor and that CDs enhanced the toxicity of metolachlor enantioselectively by increasing the aquatic toxicity of Rac-metolachlor rather than that of S-metolachlor to S. obliquus. The equilibrium constant for Rac-metolachlor-CD complexes was higher than that of S-metolachlor-CDs, which was responsible for the greater aquatic toxicity shift effect of Rac-metolachlor. Thermodynamic studies of CD complexes showed that inclusion for all of the complexes was primarily a spontaneous, enthalpy-driven process. These results will help to understand the preliminary mechanism of shifting aquatic toxicity of metolachlor by CDs and the CDs mediated environmental processes of metolachlor, to correctly apply CDs to chiral pesticides formulation and environmental remediation of chiral contaminants. PMID:22180313

  17. 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.

  18. Anaerobic co-digestion of pig manure and algae: impact of intracellular algal products recovery on co-digestion performance.

    PubMed

    Astals, S; Musenze, R S; Bai, X; Tannock, S; Tait, S; Pratt, S; Jensen, P D

    2015-04-01

    This paper investigates anaerobic co-digestion of pig manure and algae (Scenedesmus sp.) with and without extraction of intracellular algal co-products, with views towards the development of a biorefinery concept for lipid, protein and/or biogas production. Protein and/or lipids were extracted from Scenedesmus sp. using free nitrous acid pre-treatments and solvent-based Soxhlet extraction, respectively. Processing increased algae methane yield between 29% and 37% compared to raw algae (VS basis), but reduced the amount of algae available for digestion. Co-digestion experiments showed a synergy between pig manure and raw algae that increased raw algae methane yield from 0.163 to 0.245 m(3) CH4 kg(-1)VS. No such synergy was observed when algal residues were co-digested with pig manure. Finally, experimental results were used to develop a high-level concept for an integrated biorefinery processing pig manure and onsite cultivated algae, evaluating methane production and co-product recovery per mass of pig manure entering the refinery.

  19. 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

  20. 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.

  1. 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.

  2. Effect of ferric ion on nitrogen consumption, biomass and oil accumulation of a Scenedesmus rubescens-like microalga.

    PubMed

    Lin, Qiang; Gu, Na; Lin, Junda

    2012-05-01

    This investigation examined the effects of ferric ion source and concentration on the biomass yield, fatty acid methyl esters (FAME) productivity and composition from Scenedesmus rubescens-like microalga. The algae cultivated with Fe(2+)-SO(4)(2-)/EDTA had higher ash free dry biomass (AFDB) production and in vivo chlorophyll a concentration than those with Fe(2+)-SO(4)(2-) and Fe(3+)-Cl(-) (P<0.001). The high or low Fe(2+) concentration can partly restrict the ammonia consumption, the AFDB and FAME accumulation. The algae at 1mg/L Fe(2+) concentration had the highest AFDB and FAME productivity (341.1 ± 25.8 and 107.8 ± 19.3mg/L/d) (P<0.001). The mean content of C16 and C18 series at all Fe(2+) concentrations was 88.6% ± 2.9% of total FAME, and it decreased with the increase of Fe(2+) concentrations. Among the fatty acids profiles, the contents of C18: 0, C18: 1n-7 and C18: 1n-9 are significantly changed under the different Fe(2+) concentrations, but not the contents of C16 series.

  3. Beta-blockers in the environment: part II. Ecotoxicity study.

    PubMed

    Maszkowska, Joanna; Stolte, Stefan; Kumirska, Jolanta; Łukaszewicz, Paulina; Mioduszewska, Katarzyna; Puckowski, Alan; Caban, Magda; Wagil, Marta; Stepnowski, Piotr; Białk-Bielińska, Anna

    2014-09-15

    The increasing consumption of beta-blockers (BB) has caused their presence in the environment to become more noticeable. Even though BB are safe for human and veterinary usage, ecosystems may be exposed to these substances. In this study, three selected BB: propranolol, metoprolol and nadolol were subjected to ecotoxicity study. Ecotoxicity evaluation was based on a flexible ecotoxicological test battery including organisms, representing different trophic levels and complexity: marine bacteria (Vibrio fischeri), soil/sediment bacteria (Arthrobacter globiformis), green algae (Scenedesmus vacuolatus) and duckweed (Lemna minor). All the ecotoxicological studies were supported by instrumental analysis to measure deviation between nominal and real test concentrations. Based on toxicological data from the green algae test (S. vacuolatus) propranolol and metoprolol can be considered to be harmful to aquatic organisms. However, sorption explicitly inhibits the hazardous effects of BB, therefore the risks posed by these compounds for the environment are of minor importance. PMID:24975494

  4. Beta-blockers in the environment: part II. Ecotoxicity study.

    PubMed

    Maszkowska, Joanna; Stolte, Stefan; Kumirska, Jolanta; Łukaszewicz, Paulina; Mioduszewska, Katarzyna; Puckowski, Alan; Caban, Magda; Wagil, Marta; Stepnowski, Piotr; Białk-Bielińska, Anna

    2014-09-15

    The increasing consumption of beta-blockers (BB) has caused their presence in the environment to become more noticeable. Even though BB are safe for human and veterinary usage, ecosystems may be exposed to these substances. In this study, three selected BB: propranolol, metoprolol and nadolol were subjected to ecotoxicity study. Ecotoxicity evaluation was based on a flexible ecotoxicological test battery including organisms, representing different trophic levels and complexity: marine bacteria (Vibrio fischeri), soil/sediment bacteria (Arthrobacter globiformis), green algae (Scenedesmus vacuolatus) and duckweed (Lemna minor). All the ecotoxicological studies were supported by instrumental analysis to measure deviation between nominal and real test concentrations. Based on toxicological data from the green algae test (S. vacuolatus) propranolol and metoprolol can be considered to be harmful to aquatic organisms. However, sorption explicitly inhibits the hazardous effects of BB, therefore the risks posed by these compounds for the environment are of minor importance.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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

  11. Effect of retorted-oil shale leachate on a blue-green alga (Anabaena flos-aquae)

    SciTech Connect

    McKnight, D.M.; Pereira, W.E.; Rostad, C.E.; Stiles, E.A.

    1983-01-01

    Oil shale reserves in Piceance Creek and the White River, Colorado, contain retorted-shale piles which may pollute th eground water through leaching. Bioassay experiments were carried out to determine the effects of leachates on algae, particularly ANABAENA FLOSAQUAE and SCENEDESMUS. Tests were done to establish inhibitionary concentrations of the leachates from various sources of spent shale. Retorted-shale leachates had major effects on the algae papulations at a 40% concentration, minor effects at 8%, and no effects at 0.4%. Discrepancies between experimental results and actual retorted-shale piles are dixcussed. (JMT)

  12. 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.

  13. 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

  14. 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

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

    PubMed

    Li, Xiaomin; Zhou, Suyang; Fan, Wenhong

    2016-06-09

    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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa) fed Chlorella vulgaris and Scenedesmus acutus cultured on different media.

    PubMed

    Morales-Ventura, Jesús; Nandini, S; Sarma, S S S; Castellanos-Páez, Maria Elena

    2012-09-01

    Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold's basal) medium or the commercial liquid fertilizer (Bayfolan). Experiments were conducted at one algal concentration 1.0 x 10(6) cells/mL of C. vulgaris or its equivalent dry weight of 0.5 x 10(6) cells/mL of S. acutus. The population dynamics were tested at 23 +/- 1 degrees C in 100 mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates). For the life table experiments with M. macrocopa, we introduced 10 neonates (<24h old) into each test jar containing the specific algal type and concentration. For the rotifer experiments, we set 5mL tubes with one neonate each and 10 replicates for each algal species and culture medium. We found that the average rotifer life span was not influenced by the diet, but for M. macrocopa fed S. acutus cultured in Bold's medium, the average lifespan was significantly lower than with the other diets. The gross and net reproductive rates of A. fissa (ranging from 18-36 offspring per female) were significantly higher for C vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive rates for B. rubens than S. acutus diets. The reproductive rates of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase rate, derived from growth experiments of A. fissa and B. rubens

  2. Salinity induced oxidative stress enhanced biofuel production potential of microalgae Scenedesmus sp. CCNM 1077.

    PubMed

    Pancha, Imran; Chokshi, Kaumeel; Maurya, Rahulkumar; Trivedi, Khanjan; Patidar, Shailesh Kumar; Ghosh, Arup; Mishra, Sandhya

    2015-01-01

    Microalgal biomass is considered as potential feedstock for biofuel production. Enhancement of biomass, lipid and carbohydrate contents in microalgae is important for the commercialization of microalgal biofuels. In the present study, salinity stress induced physiological and biochemical changes in microalgae Scenedesmus sp. CCNM 1077 were studied. During single stage cultivation, 33.13% lipid and 35.91% carbohydrate content was found in 400 mM NaCl grown culture. During two stage cultivation, salinity stress of 400 mM for 3 days resulted in 24.77% lipid (containing 74.87% neutral lipid) along with higher biomass compared to single stage, making it an efficient strategy to enhance biofuel production potential of Scenedesmus sp. CCNM 1077. Apart from biochemical content, stress biomarkers like hydrogen peroxide, lipid peroxidation, ascorbate peroxidase, proline and mineral contents were also studied to understand the role of reactive oxygen species (ROS) mediated lipid accumulation in microalgae Scenedesmus sp. CCNM 1077.

  3. 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.

  4. 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

  5. Temperature-dependent sensitivity of growth and photosynthesis of Scenedesmus obliquus, Navicula pelliculosa and two strains of Microcystis aeruginosa to the herbicide atrazine.

    PubMed

    Chalifour, Annie; Juneau, Philippe

    2011-05-01

    The temperature-dependent sensitivities of two algal species and two strains of cyanobacteria to the photosynthesis-inhibiting herbicide atrazine were evaluated in order to understand how the interaction between acclimation temperature and herbicide will affect growth and photosynthesis of aquatic microorganisms. The green alga Scenedesmus obliquus, the diatom Navicula pelliculosa and a toxic and non-toxic strain of Microcystis aeruginosa were acclimated to three different temperatures (10, 15 and 25°C) and exposed to five concentrations of the herbicide atrazine (0-0.15μM) for 72h. Growth, photosynthetic yields, energy fluxes within photosystem II and pigment content were then measured as potential responses to each treatment. With the exception of N. pelliculosa, the toxicity of atrazine was higher when microorganisms were acclimated to lower temperatures. N. pelliculosa was not only the most tolerant to atrazine, but also had a similar sensitivity to this herbicide at every temperature. The observed differences in growth sensitivity to atrazine at low temperature are associated with the ability of algae and cyanobacteria to cope with high excitation pressure, by increasing its protective carotenoid content and non-photochemical energy dissipation. Our results demonstrate that future guidelines for the protection of aquatic life should consider water temperature as an important factor influencing the toxicity of atrazine to aquatic microorganisms. PMID:21392491

  6. Temperature-dependent sensitivity of growth and photosynthesis of Scenedesmus obliquus, Navicula pelliculosa and two strains of Microcystis aeruginosa to the herbicide atrazine.

    PubMed

    Chalifour, Annie; Juneau, Philippe

    2011-05-01

    The temperature-dependent sensitivities of two algal species and two strains of cyanobacteria to the photosynthesis-inhibiting herbicide atrazine were evaluated in order to understand how the interaction between acclimation temperature and herbicide will affect growth and photosynthesis of aquatic microorganisms. The green alga Scenedesmus obliquus, the diatom Navicula pelliculosa and a toxic and non-toxic strain of Microcystis aeruginosa were acclimated to three different temperatures (10, 15 and 25°C) and exposed to five concentrations of the herbicide atrazine (0-0.15μM) for 72h. Growth, photosynthetic yields, energy fluxes within photosystem II and pigment content were then measured as potential responses to each treatment. With the exception of N. pelliculosa, the toxicity of atrazine was higher when microorganisms were acclimated to lower temperatures. N. pelliculosa was not only the most tolerant to atrazine, but also had a similar sensitivity to this herbicide at every temperature. The observed differences in growth sensitivity to atrazine at low temperature are associated with the ability of algae and cyanobacteria to cope with high excitation pressure, by increasing its protective carotenoid content and non-photochemical energy dissipation. Our results demonstrate that future guidelines for the protection of aquatic life should consider water temperature as an important factor influencing the toxicity of atrazine to aquatic microorganisms.

  7. FERMENTATIVE AND PHOTOCHEMICAL PRODUCTION OF HYDROGEN IN ALGAE

    PubMed Central

    Gaffron, Hans; Rubin, Jack

    1942-01-01

    1.. After 2 hours of fermentation in nitrogen the metabolism of those algae which were found capable of photoreduction with hydrogen changes in such a way that molecular hydrogen is released from the cell in addition to carbon dioxide. 2. The amount of hydrogen formed anaerobically in the dark depends on the amount of some unknown reserve substance in the cell. More hydrogen is formed in presence of added glucose, but no proportionality has been found between the amount of substrate added and that of hydrogen formed. This is probably due to the fact that two types of fermentation reactions exist, with little or no connection between them. Whereas mainly unknown organic acids are formed during the autofermentation, the addition of glucose causes a considerable increase in the production of lactic acid. 3. Algae which have been fermenting for several hours in the dark produce upon illumination free hydrogen at several times the rate observed in the dark, provided carbon dioxide is absent. 4. Certain concentrations of dinitrophenol strongly inhibit the evolution of hydrogen in the dark. Fermentation then continues mainly as a reaction leading to lactic acid. In such poisoned algae the photochemical liberation of hydrogen still continues. 5. If the algae are poisoned with dinitrophenol the presence of carbon dioxide will not interfere with the photochemical evolution of hydrogen. 6. The amount of hydrogen released in this new photochemical reaction depends on the presence of an unknown hydrogen donor in the cell; it can be increased by the addition of glucose but not in proportion to the amount added. 7. The results obtained allow for a more correct explanation of the anaerobic induction period previously described for Scenedesmus and similar algae. The possibility of a photochemical evolution of hydrogen had not been taken into account in the earlier experiments. 8. The origin of the hydrogen released under the influence of light is discussed. PMID:19873339

  8. 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

  9. Biodiesel production by the green microalga Scenedesmus obliquus in a recirculatory aquaculture system.

    PubMed

    Mandal, Shovon; Mallick, Nirupama

    2012-08-01

    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.

  10. Algae harvesting for biofuel production: influences of UV irradiation and polyethylenimine (PEI) coating on bacterial biocoagulation.

    PubMed

    Agbakpe, Michael; Ge, Shijian; Zhang, Wen; Zhang, Xuezhi; Kobylarz, Patricia

    2014-08-01

    There is a pressing need to develop efficient and sustainable separation technologies to harvest algae for biofuel production. In this work, two bacterial species (Escherichia coli and Rhodococus sp.) were used as biocoagulants to harvest Chlorella zofingiensis and Scenedesmus dimorphus. The influences of UV irradiation and polyethylenimine (PEI)-coating on the algal harvesting efficiency were investigated. Results showed that the UV irradiation could slightly enhance bacteria-algae biocoagulation and algal harvesting efficiency. In contrast, the PEI-coated E. coli cells noticeably increased the harvesting efficiencies from 23% to 83% for S. dimorphus when compared to uncoated E. coli cells. Based on the soft-particle Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, an energy barrier existed between uncoated E. coli cells and algal cells, whereas the PEI coating on E. coli cells eliminated the energy barrier, thereby the biocoagulation was significantly improved. Overall, this work presented groundwork toward the potential use of bacterial biomass for algal harvesting from water.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. Accumulation characteristics of soluble algal products (SAP) by a freshwater microalga Scenedesmus sp. LX1 during batch cultivation for biofuel production.

    PubMed

    Yu, Yin; Hu, Hong-Ying; Li, Xin; Wu, Yin-Hu; Zhang, Xue; Jia, Sheng-Lan

    2012-04-01

    Algae cultivation is the essential basis for microalgal biofuel production. Soluble algal products (SAP) are significant obstacle to large-scale, high-cell-density cultivation processes. SAP accumulation during batch cultivation of Scenedesmus sp. LX1 (a unique strain accumulating lipid substantially while growing fast under low-nutrient conditions) with different initial nitrogen concentrations (7.4-34.0mgNL(-1)) was investigated. The SAP content varied in the range of 3.4-17.4mgDOCL(-1) at stationary phase, with average yield per cell of 0.5-2.5pgDOCcell(-1). High SAP accumulation up to 15.2-17.4mgDOCL(-1) were observed with initial nitrogen above 20.2mgNL(-1). The maximum SAP production rate per unit culture volume (r(SAP)) was 2.6mgDOC(Ld)(-1) and that per cell (ν(SAP)) was 1.5pgDOC(celld)(-1). The r(SAP) increased with cell growth rate and decreased with cell density linearly. The SAP accumulation was majorly due to the release of growth-associated products.

  18. 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.

  19. Comparison of R-metalaxyl and rac-metalaxyl in acute, chronic, and sublethal effect on aquatic organisms: Daphnia magna, Scenedesmus quadricanda, and Danio rerio.

    PubMed

    Yao, Kun; Zhu, Lin; Duan, Zhenghua; Chen, Zhongzhi; Li, Yan; Zhu, Xiaoshan

    2009-04-01

    Chiral pesticides are used widely in the world, and at present, older racemic products are being replaced by enantiopure products because of accelerated development of asymmetry synthesis techniques. Pesticides as xenobiotic released into environment impose a great stress on nontarget organisms. Although it is a necessary procedure for pesticides to have a registration based on toxicological data from nontarget organism, until now ecological risk assessment about metalaxyl only depend on racemic products. Hence, we investigated the acute, chronic, and sublethal toxicity of R-metalaxy and rac-metalaxyl on aquatic organisms such as D. magna (Daphnia magna), algae (Scenedesmus quadricanda), and adult zebrafish (Danio rerio). The results showed a significant difference in toxicity between R-metalaxyl and rac-metalaxyl. R-Metalaxy was about 20-fold more toxic to algae than rac-metalaxyl with IC(50) of 222.89 +/- 1.18 mg/L and 19.95 +/- 1.12 mg/L, respectively. Similarly, R-metalaxyl was about fourfold toxic to D. magna than rac-metalaxyl according to the individual 24-h-LC(50) values, and sixfold toxic than rac-metalaxyl based on 24-h-EC(50) values. In the light of 48-h-LC(50) and EC(50), this difference in toxicity was more significant. As for adult zebrafish, there was no pronounced difference in acute toxicity, in addition, at sublethal level a different pattern in inducing Na(+),K(+)-ATPase activity between them was found. In general, R-metalaxyl seemed more toxic to aquatic organisms than rac-metalaxyl. PMID:18563802

  20. 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.

  1. 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

  2. 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

  3. Blue-green algae

    MedlinePlus

    “Blue-green algae” describes a large and diverse group of simple, plant-like organisms found in salt water and some large fresh water lakes. Blue-green algae products are used for many conditions, but so ...

  4. Enantioselective ecotoxicity of the herbicide dichlorprop and complexes formed with chitosan in two fresh water green algae.

    PubMed

    Wen, Yuezhong; Chen, Hui; Yuan, Yuli; Xu, Dongmei; Kang, Xiaodong

    2011-04-01

    To reduce the leaching potential, to prevent groundwater contamination and to maintain the efficacy of a pesticide, natural polysaccharides have received increasing attention due to their biocompatibility and useful biological reactivity for controlled release formulations (CRFs) of pesticides. In this paper, the toxicities of the chiral herbicide dichlorprop (DCPP) and its complexes with chitosan molecules (DCPP-CS) and chitosan nanoparticles (DCPP-NP) to two different green algae were determined and compared. The inhibition rates of DCPP, DCPP-CS and DCPP-NP were determined at 24, 48, 72, 96, 120, 144, 168 h, and the results show that (S)-DCPP was more toxic to Chlorella vulgaris than (R)-DCPP, while the (R)-DCPP was more toxic to Scenedesmus obliquus than (S)-DCPP. The study also found that the chiral selectivity of DCPP to Chlorella vulgaris and Scenedesmus obliquus could be changed when DCPP was complexed with chitosan molecules (CS) or chitosan nanoparticles (NP). For Chlorella vulgaris, the order of inhibition was (R)-DCPP-CS > (S)-DCPP-CS and (R)-DCPP-NP > (S)-DCPP-NP; for Scenedesmus obliquus, the order was (S)-DCPP-CS > (R)-DCPP-CS and (S)-DCPP-NP > (R)-DCPP-NP. This phenomenon suggests that the enantioselective behaviors of chiral compounds might shift when interactions with other chiral receptors coexist in different biological environments. Additionally, chitosan molecules and chitosan nanoparticles also showed different toxicities, which could be ascribed to the difference in the physicochemical properties between CS and NP or the differences in the cell walls of the two fresh water green algae.

  5. 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.

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

    USGS Publications Warehouse

    Fairchild, James F.; Ruessler, Shane; Carlson, A. Ron

    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.

  7. 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.

  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. Maximizing biomass productivity and CO2 biofixation of microalga, Scenedesmus sp. by using sodium hydroxide.

    PubMed

    Nayak, Manoranjan; Rath, Swagat S; Thirunavoukkarasu, Manikkannan; Panda, Prasanna K; Mishra, Barada K; Mohanty, Rama C

    2013-09-28

    A series of experiments were carried out with three native strains of microalgae to measure growth rates, biomass, and lipid productivities. Scenedesmus sp. IMMTCC-6 had better biomass growth rate and higher lipid production. The growth, lipid accumulation, and carbon dioxide (CO2) consumption rate of Scenedesmus sp. IMMTCC-6 were tested under different NaOH concentrations in modified BBM. The algal strain showed the maximum specific growth rate (0.474/day), biomass productivity (110.9 mg l(-1) d(-1)), and CO2 consumption rate (208.4 mg l(-1) d(-1)) with an NaOH concentration of 0.005 M on the 8(th) day of cultivation. These values were 2.03-, 6.89-, and 6.88-fold more than the algal cultures grown in control conditions (having no NaOH and CO2). The CO2 fixing efficiency of the microalga with other alternative carbon sources like Na2CO3 and NaHCO3 was also investigated and compared. The optimized experimental parameters at shake-flask scale were implemented for scaling up the process in a self-engineered photobioreactor. A significant increase in lipid accumulation (14.23% to 31.74%) by the algal strain from the logarithmic to stationary phases was obtained. The algal lipids were mainly composed of C16/C18 fatty acids, and are desirable for biodiesel production. The study suggests that microalga Scenedesmus sp. IMMTCC-6 is an efficient strain for biodiesel production and CO2 biofixation using stripping solution of NaOH in a cyclic process.

  10. 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.

  11. Pre-treatment optimization of Scenedesmus obliquus microalga for bioethanol production.

    PubMed

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

    2012-01-01

    The present work deals with the optimization of cellular disruption and sugar extraction from the microalgae Scenedesmus obliquus (Sc) for bioethanol production. Among the physical and physicochemical methods tested, the best results were obtained with acid hydrolysis by H(2)SO(4) (2N), at 120 °C for 30 min and using dried biomass. The sugar extraction efficiency level reached was 95.6% when compared to the harsh quantitative acid hydrolysis. The influence of other parameters such as biomass loading and number of extraction cycles were also evaluated. The results obtained in the latter case showed that a unique hydrolysis step is sufficient.

  12. 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.

  13. Salicylhydroxamic Acid (SHAM) Inhibition of the Dissolved Inorganic Carbon Concentrating Process in Unicellular Green Algae.

    PubMed

    Goyal, A; Tolbert, N E

    1990-03-01

    Rates of photosynthetic O(2) evolution, for measuring K(0.5)(CO(2) + HCO(3) (-)) at pH 7, upon addition of 50 micromolar HCO(3) (-) 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(1)(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(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(2) evolution dependent on low levels of dissolved inorganic carbon (50 micromolar Na-HCO(3)), and the rate of (14)CO(2) fixation with 100 micromolar [(14)C] HCO(3) (-). Salicylhydroxamic acid inhibition of O(2) evolution and (14)CO(2)-fixation was reversed by higher levels of NaHCO(3). Thus, salicylhydroxamic acid inhibition was apparently not affecting steps of photosynthesis other than CO(2) accumulation. Although salicylhydroxamic acid is an inhibitor of alternative respiration in algae, it is not known whether the two processes are related.

  14. Assessment of the ecotoxic potential of soil contaminants by using a soil-algae test.

    PubMed

    Hammel, W; Steubing, L; Debus, R

    1998-01-01

    To assess the ecotoxic potential of soil contaminants, a test with the soil alga Chlorococcum infusionum has been developed, enabling investigations of soil pollutions with soluble and fairly soluble chemicals. Three soil types artificially contaminated with Sb compounds and five soils from a historical mining area, which were highly polluted with Sb, As, Hg, and Cu, were used as test soils. For antimony, EC50 values from 125 mg/kg up to > 1000 mg/kg, depending on soil type, were determined. Two of five soils from the mining area caused toxic effects. Additionally, aqueous extracts of all soils were exposed in established tests (daphnid, alga, bacterium). In contrast with the soil-algae test, no toxic effects were found. Aquatic tests with SbO/K tartrate were performed to point out the toxicity of antimony. The following EC50 values in milligrams of Sb per liter were determined: Scenedesmus subspicatus, 59 mg/liter; Chlorococcum infusionum, 43 mg/liter; Daphnia magna, 8 mg/liter; and Vibrio fisheri, 7 mg/liter.

  15. Modeling the dynamic modulation of light energy in photosynthetic algae.

    PubMed

    Papadakis, Ioannis A; Kotzabasis, Kiriakos; Lika, Konstadia

    2012-05-01

    An integrated cell-based dynamic mathematical model that take into account the role of the photon absorbing process, the partition of excitation energy, and the photoinactivation and repair of photosynthetic units, under variable light and dissolved inorganic carbon (DIC) availability is proposed. The modeling of the photon energy absorption and the energy dissipation is based on the photoadaptive changes of the underlying mechanisms. The partition of the excitation energy is based on the relative availability of light and DIC to the cell. The modeling of the photoinactivation process is based on the common aspect that it occurs under any light intensity and the modeling of the repair process is based on the evidence that it is controlled by chloroplast and nuclear-encoded enzymes. The present model links the absorption of photons and the partitioning of excitation energy to the linear electron flow and other quenchers with chlorophyll fluorescence emission parameters, and the number of the functional photosynthetic units with the photosynthetic oxygen production rate. The energy allocation to the LEF increases as DIC availability increases and/or light intensity decreases. The rate of rejected energy increases with light intensity and with DIC availability. The resulting rate coefficient of photoinactivation increases as light intensity and/or as DIC concentration increases. We test the model against chlorophyll fluorescence induction and photosynthetic oxygen production rate measurements, obtained from cultures of the unicellular green alga Scenedesmus obliquus, and find a very close quantitative and qualitative correspondence between predictions and data.

  16. 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

  17. 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.

  18. 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

  19. Optimization of medium using response surface methodology for lipid production by Scenedesmus sp.

    PubMed

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

    2014-03-01

    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.

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

    PubMed

    Abinandan, S; Bhattacharya, Ribhu; Shanthakumar, S

    2015-01-01

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

  1. 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

  2. Origin of the algae.

    PubMed

    Perasso, R; Baroin, A; Qu, L H; Bachellerie, J P; Adoutte, A

    1989-05-11

    Eukaryotic algae are traditionally separated into three broad divisions: the rhodophytes, the chromophytes and the chlorophytes. The evolutionary relationships between these groups, their links with other eukaryotes and with other photosynthetic groups, such as euglenophytes and cryptophytes, have been the subject of much debate and speculation. Here we analyse partial sequences of the large (28S) cytoplasmic ribosomal RNA from ten new species of protists belonging to various groups of unicellular algae. By combining them with the homologous sequences from 14 other unicellular and multicellular eukaryotes, we show that rhodophytes, chromophytes and chlorophytes emerge as three distinct groups late among eukaryotes, that is, close to the metazoa-metaphytes radiation. This implies a relatively late occurrence of eukaryotic photosynthetic symbiosis. We also provide details of intra- and inter-phyla relationships.

  3. 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

  4. Development of genetic transformation methodologies for an industrially-promising microalga: Scenedesmus almeriensis.

    PubMed

    Dautor, Yasmeen; Úbeda-Mínguez, Patricia; Chileh, Tarik; García-Maroto, Federico; Alonso, Diego López

    2014-12-01

    The development of the microalgal industry requires advances in every aspect of microalgal biotechnology. In this regard, the availability of genetic engineering tools for industrially-promising species is key. As Scenedesmus almeriensis has promise for industrial use, we describe here an Agrobacterium-based methodology that allows stable genetic transformation of it for the first time, thus opening the way to its genetic manipulation. Transformation was accomplished using two different antibiotic resistance genes [hygromicine phophotransferase (hpt) and Shble] and it is credited by PCR amplification of both hpt/Shble and GUS genes and by the β-glucuronidase activity of transformed cells. Nevertheless, the single 35S promoter seems unable to direct gene expression to a convenient level in S. almeriensis as suggested by the low GUS enzymatic activity. Temperature was critical for the transformation efficiency.

  5. Chronic effects of the ionic liquid [C4mim][Cl] towards the microalga Scenedesmus quadricauda.

    PubMed

    Deng, Yun; Beadham, Ian; Wu, Jie; Chen, Xiao-Di; Hu, Lan; Gu, Jun

    2015-09-01

    Chronic effects of the ionic liquid [C4mim][Cl] (mp 73 °C) towards the microalga, Scenedesmus quadricauda were studied by flow cytometry, monitoring multiple endpoints of cell density, esterase activity, membrane integrity, reactive oxygen species and chlorophyll fluorescence. Toxicity was clearly in evidence, and although increased esterase activity indicated hormesis during initial exposure to [C4mim][Cl], inhibition of both esterase activity and chlorophyll fluorescence became apparent after 3 days. Cell density was also decreased by culturing with [C4mim][Cl], but this effect was clearly concentration-dependent and only became significant during the second half of the experiment. In contrast, [C4mim][Cl] had only a modest effect on reactive oxygen species (ROS) and caused little damage to cell membranes. PMID:25989452

  6. 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.

  7. 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

  8. Effects of simulated flue gas on components of Scenedesmus raciborskii WZKMT.

    PubMed

    Li, Xie-kun; Xu, Jing-liang; Guo, Ying; Zhou, Wei-zheng; Yuan, Zhen-hong

    2015-08-01

    Scenedesmus raciborskii WZKMT cultured with simulated flue gas was investigated. Cellular components, including total sugar, starch, chlorophyll, protein and lipid, were compared between simulated flue gas and 7% (v/v) CO2. Dissolution of SO2 and NO in simulated flue gas led to pH decrease and toxicity to microalgae cells. Furthermore, the death or aging of microalgae cells reduced the buffer capacity and caused decrease of simulated flue gas absorption. With 7% CO2, the highest total sugar and starch content could attain to 66.76% and 53.16%, respectively, which indicated S. raciborskii WZKMT is a desired feedstock candidate for bioethanol production. Microalgae growth and starch accumulation was inhibited, while cells produced more chlorophyll, protein and lipid when simulated flue gas was the carbon source. Fatty acids composition analysis indicated that there was no significant distinction on fatty acids relative content (fatty acid/TFA) between cells aerated using simulated flue gas and 7% CO2.

  9. 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

  10. Lineage-specific fragmentation and nuclear relocation of the mitochondrial cox2 gene in chlorophycean green algae (Chlorophyta).

    PubMed

    Rodríguez-Salinas, Elizabeth; Riveros-Rosas, Héctor; Li, Zhongkui; Fucíková, Karolina; Brand, Jerry J; Lewis, Louise A; González-Halphen, Diego

    2012-07-01

    In most eukaryotes the subunit 2 of cytochrome c oxidase (COX2) is encoded in intact mitochondrial genes. Some green algae, however, exhibit split cox2 genes (cox2a and cox2b) encoding two polypeptides (COX2A and COX2B) that form a heterodimeric COX2 subunit. Here, we analyzed the distribution of intact and split cox2 gene sequences in 39 phylogenetically diverse green algae in phylum Chlorophyta obtained from databases (28 sequences from 22 taxa) and from new cox2 data generated in this work (23 sequences from 18 taxa). Our results support previous observations based on a smaller number of taxa, indicating that algae in classes Prasinophyceae, Ulvophyceae, and Trebouxiophyceae contain orthodox, intact mitochondrial cox2 genes. In contrast, all of the algae in Chlorophyceae that we examined exhibited split cox2 genes, and could be separated into two groups: one that has a mitochondrion-localized cox2a gene and a nucleus-localized cox2b gene ("Scenedesmus-like"), and another that has both cox2a and cox2b genes in the nucleus ("Chlamydomonas-like"). The location of the split cox2a and cox2b genes was inferred using five different criteria: differences in amino acid sequences, codon usage (mitochondrial vs. nuclear), codon preference (third position frequencies), presence of nucleotide sequences encoding mitochondrial targeting sequences and presence of spliceosomal introns. Distinct green algae could be grouped according to the form of cox2 gene they contain: intact or fragmented, mitochondrion- or nucleus-localized, and intron-containing or intron-less. We present a model describing the events that led to mitochondrial cox2 gene fragmentation and the independent and sequential migration of cox2a and cox2b genes to the nucleus in chlorophycean green algae. We also suggest that the distribution of the different forms of the cox2 gene provides important insights into the phylogenetic relationships among major groups of Chlorophyceae.

  11. Toxicity and bioaccumulation kinetics of arsenate in two freshwater green algae under different phosphate regimes.

    PubMed

    Wang, Ning-Xin; Li, Yan; Deng, Xi-Hai; Miao, Ai-Jun; Ji, Rong; Yang, Liu-Yan

    2013-05-01

    In the present study, the toxicity and bioaccumulation kinetics of arsenate in two green algae Chlamydomonas reinhardtii and Scenedesmus obliquus under phosphate-enriched (+P) and limited (-P) conditions were investigated. P-limitation was found to aggravate arsenate toxicity and S. obliquus was more tolerant than C. reinhardtii. Such phosphate-condition-dependent or algal-species-specific toxicity difference was narrowed when the relative inhibition of cell growth was plotted against intracellular arsenate content instead of its extracellular concentration. The discrepance was further reduced when the intracellular ratio of arsenic to phosphorus was applied. It suggests that both arsenate bioaccumulation and intracellular phosphorus played an important role in arsenate toxicity. On the other hand, arsenate uptake was induced by P-limitation and its variation with ambient arsenate concentration could be well fitted to the Michaelis-Menten model. Arsenate transporters of S. obliquus were found to have a higher affinity but lower capacity than those of C. reinhardtii, which explains its better regulation of arsenate accumulation than the latter species in the toxicity experiment. Further, arsenate depuration was facilitated and more was transformed to arsenite in C. reinhardtii or under -P condition. Intracellular proportion of arsenite was also increased after the algae were transferred from the long-term uptake media to a relatively clean solution in the efflux experiment. Both phenomena imply that algae especially the sensitive species could make physiological adjustments to alleviate the adverse effects of arsenate. Overall, our findings will facilitate the application of algae in arsenate remediation. PMID:23497978

  12. 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.

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

    PubMed

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

    2011-12-01

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

  14. 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

  15. 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.

  16. 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

  17. Cellular Auxin Transport in Algae.

    PubMed

    Zhang, Suyun; van Duijn, Bert

    2014-01-27

    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.

  18. 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.

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

    SciTech Connect

    2010-01-15

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

  20. [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

  1. Transgenic algae engineered for higher performance

    SciTech Connect

    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.

  2. Toxicity of anthelmintic drugs (fenbendazole and flubendazole) to aquatic organisms.

    PubMed

    Wagil, Marta; Białk-Bielińska, Anna; Puckowski, Alan; Wychodnik, Katarzyna; Maszkowska, Joanna; Mulkiewicz, Ewa; Kumirska, Jolanta; Stepnowski, Piotr; Stolte, Stefan

    2015-02-01

    Flubendazole (FLU) and fenbendazole (FEN) belong to benzimidazoles-pharmaceuticals widely used in veterinary and human medicine for the treatment of intestinal parasites as well as for the treatment of systemic worm infections. In recent years, usage of these drugs increased, which resulted in a larger contamination of the environment and possible negative effects on biota. Hence, in our research, we investigated an aquatic ecotoxicity of these pharmaceuticals towards: marine bacteria (Vibrio fischeri), green algae (Scenedesmus vacuolatus), duckweed (Lemna minor) and crustacean (Daphnia magna). Ecotoxicity tests were combined with chemical analysis in order to investigate the actual exposure concentration of the compounds used in the experiment as well as to stability and adsorption studies. As a result, study evaluating sensitivity of different aquatic organisms to these compounds and new ecotoxicological data is presented. The strongest negative impact of FLU and FEN was observed to D. magna.

  3. Toxicity of anthelmintic drugs (fenbendazole and flubendazole) to aquatic organisms.

    PubMed

    Wagil, Marta; Białk-Bielińska, Anna; Puckowski, Alan; Wychodnik, Katarzyna; Maszkowska, Joanna; Mulkiewicz, Ewa; Kumirska, Jolanta; Stepnowski, Piotr; Stolte, Stefan

    2015-02-01

    Flubendazole (FLU) and fenbendazole (FEN) belong to benzimidazoles-pharmaceuticals widely used in veterinary and human medicine for the treatment of intestinal parasites as well as for the treatment of systemic worm infections. In recent years, usage of these drugs increased, which resulted in a larger contamination of the environment and possible negative effects on biota. Hence, in our research, we investigated an aquatic ecotoxicity of these pharmaceuticals towards: marine bacteria (Vibrio fischeri), green algae (Scenedesmus vacuolatus), duckweed (Lemna minor) and crustacean (Daphnia magna). Ecotoxicity tests were combined with chemical analysis in order to investigate the actual exposure concentration of the compounds used in the experiment as well as to stability and adsorption studies. As a result, study evaluating sensitivity of different aquatic organisms to these compounds and new ecotoxicological data is presented. The strongest negative impact of FLU and FEN was observed to D. magna. PMID:25189803

  4. Modelling of Scenedesmus obliquus; function of nutrients with modified Gompertz model.

    PubMed

    Celekli, Abuzer; Balci, Muharrem; Bozkurt, Hüseyin

    2008-12-01

    This study attempted to investigate variation in biovolume of Scenedesmus obliquus, in the modified Johnson medium at 20+/-2 degrees C, under 16kergcm(-2)s(-1) continuous illumination. The experiments were carried out at four nitrate (8, 12, 16, and 20mM) and four phosphate (0.1, 0.3, 0.5 and 0.7mM) concentrations at pH 7 and 8. The best response for algal growth was found at 0.3mM phosphate and 12mM nitrate at pH 7, as it was obtained from weight averaging method. Besides, optimum phosphate and nitrate concentrations significantly distinguished (p<0.01) from other concentrations according to Turkey's HSD test. Key features of the growth of S. obliquus under phosphate and nitrate influenced batch culture was successfully predicted by modified Gompertz model. Through the cultivations, specific growth rate (mu) ranged from 0.30 to 1.02 day(-1), while biovolume doubling time (td) varied from 0.68 to 2.30 days. There were important differences (p<0.05) for both mu and td among response variables. Both nutrients displayed noteworthy effect (p<0.01) on the algal biovolume. PMID:18501595

  5. 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

  6. 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

  7. Modelling of Scenedesmus obliquus; function of nutrients with modified Gompertz model.

    PubMed

    Celekli, Abuzer; Balci, Muharrem; Bozkurt, Hüseyin

    2008-12-01

    This study attempted to investigate variation in biovolume of Scenedesmus obliquus, in the modified Johnson medium at 20+/-2 degrees C, under 16kergcm(-2)s(-1) continuous illumination. The experiments were carried out at four nitrate (8, 12, 16, and 20mM) and four phosphate (0.1, 0.3, 0.5 and 0.7mM) concentrations at pH 7 and 8. The best response for algal growth was found at 0.3mM phosphate and 12mM nitrate at pH 7, as it was obtained from weight averaging method. Besides, optimum phosphate and nitrate concentrations significantly distinguished (p<0.01) from other concentrations according to Turkey's HSD test. Key features of the growth of S. obliquus under phosphate and nitrate influenced batch culture was successfully predicted by modified Gompertz model. Through the cultivations, specific growth rate (mu) ranged from 0.30 to 1.02 day(-1), while biovolume doubling time (td) varied from 0.68 to 2.30 days. There were important differences (p<0.05) for both mu and td among response variables. Both nutrients displayed noteworthy effect (p<0.01) on the algal biovolume.

  8. 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).

  9. Effect of intracellular P content on phosphate removal in Scenedesmus sp. Experimental study and kinetic expression.

    PubMed

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

    2015-01-01

    The present work determines the effect of phosphorus content on phosphate uptake rate in a mixed culture of Chlorophyceae in which the genus Scenedesmus dominates. Phosphate uptake rate was determined in eighteen laboratory batch experiments, with samples taken from a progressively more P-starved culture in which a minimum P content of 0.11% (w/w) was achieved. The results obtained showed that the higher the internal biomass P content, the lower the phosphate removal rate. The highest specific phosphate removal rate was 6.5mgPO4-PgTSS(-1)h(-1). Microalgae with a P content around 1% (w/w) attained 10% of this highest removal rate, whereas those with a P content of 0.6% (w/w) presented 50% of the maximum removal rate. Different kinetic expressions were used to reproduce the experimental data. Best simulation results for the phosphate uptake process were obtained combining Steele equation and Hill function to represent the effect of light and intracellular phosphorus content, respectively.

  10. Biosorption of cadmium by CO(2)-fixing microalga Scenedesmus obliquus CNW-N.

    PubMed

    Chen, Chun-Yen; Chang, Hao-Wei; Kao, Pei-Chun; Pan, Jian-Liang; Chang, Jo-Shu

    2012-02-01

    An efficient CO(2)-fixing indigenous microalga Scenedesmus obliquus CNW-N was used as the biosorbent to remove cadmium from aqueous solution. The microalga was grown with continuous feeding of 2.5% CO(2), achieving a maximum CO(2) consumption rate of 495 mg/l/d and a biomass production of 2.56 g/l. Cadmium (Cd) biosorption by S. obliquus CNW-N was optimal at pH 6.0 and 30 °C. For an initial cadmium concentration of 50mg/l, the biosorption capacity tended to decrease with an increase in biosorbent, while the cadmium removal efficiency was nearly 100% when the biosorbent loading was higher than 0.6g. The biosorption kinetics followed the pseudo-second order adsorption model. The adsorption equilibrium obeys Langmuir isotherm with an estimated maximum capacity of 68.6 mg/g and a saturation coefficient of 0.101 l/mg. The cadmium-loaded microalgal biomass could be regenerated preferably with 0.05 M CaCl(2), as the regenerated biosorbent retained good adsorption capability after five consecutive adsorption/desorption cycles.

  11. 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.

  12. Cultivating Chlorella vulgaris and Scenedesmus quadricauda microalgae to degrade inorganic compounds and pesticides in water.

    PubMed

    Baglieri, Andrea; Sidella, Sarah; Barone, Valeria; Fragalà, Ferdinando; Silkina, Alla; Nègre, Michèle; Gennari, Mara

    2016-09-01

    This work evaluates the possibility of cultivating Scenedesmus quadricauda and Chlorella vulgaris microalgae in wastewater from the hydroponic cultivation of tomatoes with the aim of purifying the water. S. quadricauda and C. vulgaris were also used in purification tests carried out on water contaminated by the following active ingredients: metalaxyl, pyrimethanil, fenhexamid, iprodione, and triclopyr. Fifty-six days after the inoculum was placed, a reduction was found in the concentration of nitric nitrogen, ammonia nitrogen, and soluble and total phosphorus. The decrease was 99, 83, 94, and 94 %, respectively, for C. vulgaris and 99, 5, 88, and 89 %, respectively, for S. quadricauda. When the microalgae were present, all the agrochemicals tested were removed more quickly from the water than from the sterile control (BG11). The increase in the rate of degradation was in the order metalaxyl > fenhexamid > iprodione > triclopyr > pyrimethanil. It was demonstrated that there was a real degradation of fenhexamid, metalaxyl, triclopyr, and iprodione, while in the case of pyrimethanil, the active ingredient removed from the substrate was absorbed onto the cells of the microalgae. It was also found that the agrochemicals used in the tests had no significant effect on the growth of the two microalgae. The experiment highlighted the possibility of using cultivations of C. vulgaris and S. quadricauda as purification systems for agricultural wastewater which contains eutrophic inorganic compounds such as nitrates and phosphates and also different types of pesticides. PMID:27259964

  13. Enhancing lutein productivity of an indigenous microalga Scenedesmus obliquus FSP-3 using light-related strategies.

    PubMed

    Ho, Shih-Hsin; Chan, Ming-Chang; Liu, Chen-Chun; Chen, Chun-Yen; Lee, Wen-Lung; Lee, Duu-Jong; Chang, Jo-Shu

    2014-01-01

    Lutein, one of the main photosynthetic pigments, is a promising natural product with both nutritional and pharmaceutical applications. In this study, light-related strategies were applied to enhance the cell growth and lutein production of a lutein-rich microalga Scenedesmus obliquus FSP-3. The results demonstrate that using white LED resulted in better lutein production efficiency when compared to the other three monochromatic LEDs (red, blue, and green). The lutein productivity of S. obliquus FSP-3 was further improved by adjusting the type of light source and light intensity. The optimal lutein productivity of 4.08 mg/L/d was obtained when using a TL5 fluorescent lamp at a light intensity of 300 μmol/m(2)/s, and this performance is better than that reported in most related studies. Moreover, the time-course profile of lutein accumulation in the microalga shows that the maximal lutein content and productivity were obtained at the onset of nitrogen depletion.

  14. 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.

  15. Comparison of ultrasound and thermal pretreatment of Scenedesmus biomass on methane production.

    PubMed

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

    2012-04-01

    Ultrasound at 20Hz was applied at different energy levels (Es) to treat Scenedesmus biomass, and organic matter solubilization, particle size distribution, cell disruption and biochemical methane potential were evaluated. An Es of 35.5 and 47.2MJ/kg resulted in floc deagglomeration but no improvement in methane production compared to untreated biomass. At an Es of 128.9, cell wall disruption was observed together with a 3.1-fold organic matter solubilization and an approximately 2-fold methane production in comparison with untreated biomass. Thermal pretreatment at 80°C caused cell wall disruption and improved anaerobic biodegradability 1.6-fold compared to untreated biomass. Since sonication caused a temperature increase in samples to as high as 85°C, it is likely that thermal effects accounted for much of the observed changes in the biomass. Given that ultrasound treatment at the highest Es studied only increased methane production by 1.2-fold over thermal treatment at 80°C, the higher energy requirement of sonication might not justify the use of this approach over thermal treatment.

  16. 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.

  17. Estrogenic activity in extracts and exudates of cyanobacteria and green algae.

    PubMed

    Sychrová, E; Štěpánková, T; Nováková, K; Bláha, L; Giesy, J P; Hilscherová, K

    2012-02-01

    Here is presented some of the first information on interactions of compounds produced by cyanobacteria and green algae with estrogen receptor signaling. Estrogenic potency of aqueous extracts and exudates (culture spent media with extracellular products) of seven species of cyanobacteria (10 different laboratory strains) and two algal species were assessed by use of in vitro trans-activation assays. Compounds produced by cyanobacteria and algae, and in particular those excreted from the cells, were estrogenic. Most exudates were estrogenic with potencies expressed at 50% of the maximum response under control of the estrogen receptor ranging from 0.2 to 7.2 ng 17β-estradiol (E(2)) equivalents (EEQ)/L. The greatest estrogenic potency was observed for exudates of Microcystis aerigunosa, a common species that forms water blooms. Aqueous extracts of both green algae, but only one species of cyanobacteria (Aphanizomenon gracile) elicited significant estrogenicity with EEQ ranging from 15 to 280 ng 17β-estradiol (E(2))/g dry weight. Scenedesmus quadricauda exudates and extracts of Aphanizomenon flos-aquae were antagonistic to the ER when coexposed to E(2). The EEQ potency was not correlated with concentrations of cyanotoxins, such as microcystin and cylindrospermopsin, which suggests that the EEQ was comprised of other compounds. The study demonstrates some differences between the estrogenic potency of aqueous extracts prepared from the same species, but of different origin, while the effects of exudates were comparable within species. The observed estrogenic potencies are important namely in relation to the possible mass expansion of cyanobacteria and release of the active compounds into surrounding water. PMID:22208753

  18. Enhanced biofuel production potential with nutritional stress amelioration through optimization of carbon source and light intensity in Scenedesmus sp. CCNM 1077.

    PubMed

    Pancha, Imran; Chokshi, Kaumeel; Mishra, Sandhya

    2015-03-01

    Microalgal mixotrophic cultivation is one of the most potential ways to enhance biomass and biofuel production. In the present study, first of all ability of microalgae Scenedesmus sp. CCNM 1077 to utilize various carbon sources under mixotrophic growth condition was evaluated followed by optimization of glucose concentration and light intensity to obtain higher biomass, lipid and carbohydrate contents. Under optimized condition i.e. 4 g/L glucose and 150 μmol m(-2) s(-1) light intensity, Scenedesmus sp. CCNM 1077 produced 1.2g/L dry cell weight containing 23.62% total lipid and 42.68% carbohydrate. Addition of glucose shown nutritional stress ameliorating effects and around 70% carbohydrate and 25% total lipid content was found with only 21% reduction in dry cell weight under nitrogen starved condition. This study shows potential application of mixotrophically grown Scenedesmus sp. CCNM 1077 for bioethanol and biodiesel production feed stock.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. Superior triacylglycerol (TAG) accumulation in starchless mutants of Scenedesmus obliquus: (I) mutant generation and characterization

    PubMed Central

    2014-01-01

    Background Microalgae are a promising platform for producing neutral lipids, to be used in the application for biofuels or commodities in the feed and food industry. A very promising candidate is the oleaginous green microalga Scenedesmus obliquus, because it accumulates up to 45% w/w triacylglycerol (TAG) under nitrogen starvation. Under these conditions, starch is accumulated as well. Starch can amount up to 38% w/w under nitrogen starvation, which is a substantial part of the total carbon captured. When aiming for optimized TAG production, blocking the formation of starch could potentially increase carbon allocation towards TAG. In an attempt to increase TAG content, productivity and yield, starchless mutants of this high potential strain were generated using UV mutagenesis. Previous studies in Chlamydomonas reinhardtii have shown that blocking the starch synthesis yields higher TAG contents, although these TAG contents do not surpass those of oleaginous microalgae yet. So far no starchless mutants in oleaginous green microalgae have been isolated that result in higher TAG productivities. Results Five starchless mutants have been isolated successfully from over 3,500 mutants. The effect of the mutation on biomass and total fatty acid (TFA) and TAG productivity under nitrogen-replete and nitrogen-depleted conditions was studied. All five starchless mutants showed a decreased or completely absent starch content. In parallel, an increased TAG accumulation rate was observed for the starchless mutants and no substantial decrease in biomass productivity was perceived. The most promising mutant showed an increase in TFA productivity of 41% at 4 days after nitrogen depletion, reached a TAG content of 49.4% (% of dry weight) and had no substantial change in biomass productivity compared to the wild type. Conclusions The improved S. obliquus TAG production strains are the first starchless mutants in an oleaginous green microalga that show enhanced TAG content under

  4. Biomass and lutein productivity of Scenedesmus almeriensis: influence of irradiance, dilution rate and temperature.

    PubMed

    Sánchez, J F; Fernández-Sevilla, J M; Acién, F G; Cerón, M C; Pérez-Parra, J; Molina-Grima, E

    2008-07-01

    In this paper, the biomass and lutein productivity of the lutein-rich new strain Scenedesmus almeriensis is modelled versus irradiance and temperature. The results demonstrate that S. almeriensis is a mesophile microorganism with an optimal growth temperature of 35 degrees C, and capable of withstanding up to 48 degrees C, which caused culture death. This strain is also tolerant to high irradiances, showing no signs of photoinhibition even at the maximum irradiance essayed of 1625 microE m(-2) s(-1) accumulating up to 0.55% dry weight (d.wt.) of lutein. The optimal conditions that maximise the biomass productivity also favour the lutein productivity, lutein being a primary metabolite. Maximal biomass and lutein productivities of 0.87 g l(-1) day(-1) and 4.77 mg l(-1) day(-1), respectively, were measured. The analysis of light availability inside the cultures, quantified as average irradiance, demonstrates that the cultures were mainly photo-limited, although photosaturation also took place at high external irradiances. The effect of temperature was also investigated finding that the specific maximal growth rate is modified by the temperature according to the Arrhenius equation. The influence of both light availability and temperature was included in an overall growth model, which showed, as a result, capable of fitting the whole set of experimental data. An overall lutein accumulation rate model was also proposed and used in a regression analysis. Simulations performed using the proposed models show that under outdoor conditions a biomass productivity of 0.95 g l(-1) day(-1) can be expected, with a lutein productivity up to 5.31 mg l(-1) day(-1). These models may be useful to assist the design and operation optimisation of outdoor cultures of this strain. PMID:18491039

  5. 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.

  6. Neuroprotective Effects of Marine Algae

    PubMed Central

    Pangestuti, Ratih; Kim, Se-Kwon

    2011-01-01

    The marine environment is known as a rich source of chemical structures with numerous beneficial health effects. Among marine organisms, marine algae have been identified as an under-exploited plant resource, although they have long been recognized as valuable sources of structurally diverse bioactive compounds. Presently, several lines of studies have provided insight into biological activities and neuroprotective effects of marine algae including antioxidant, anti-neuroinflammatory, cholinesterase inhibitory activity and the inhibition of neuronal death. Hence, marine algae have great potential to be used for neuroprotection as part of pharmaceuticals, nutraceuticals and functional foods. This contribution presents an overview of marine algal neuroprotective effects and their potential application in neuroprotection. PMID:21673890

  7. Polysaccharides of the red algae.

    PubMed

    Usov, Anatolii I

    2011-01-01

    Red algae (Rhodophyta) are known as the source of unique sulfated galactans, such as agar, agarose, and carrageenans. The wide practical uses of these polysaccharides are based on their ability to form strong gels in aqueous solutions. Gelling polysaccharides usually have molecules built up of repeating disaccharide units with a regular distribution of sulfate groups, but most of the red algal species contain more complex galactans devoid of gelling ability because of various deviations from the regular structure. Moreover, several red algae may contain sulfated mannans or neutral xylans instead of sulfated galactans as the main structural polysaccharides. This chapter is devoted to a description of the structural diversity of polysaccharides found in the red algae, with special emphasis on the methods of structural analysis of sulfated galactans. In addition to the structural information, some data on the possible use of red algal polysaccharides as biologically active polymers or as taxonomic markers are briefly discussed.

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

    SciTech Connect

    Gharagozloo, Patricia E.; Drewry, Jessica Louise.

    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.

  9. 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)

  10. The effects of sub-lethal UV-C irradiation on growth and cell integrity of cyanobacteria and green algae.

    PubMed

    Tao, Yi; Zhang, Xihui; Au, Doris W T; Mao, Xianzhong; Yuan, Kan

    2010-01-01

    The effects of UV-C irradiation on algal growth and cell integrity were investigated to develop a potential method for preventing cyanobacterial blooms. The toxic cyanobacterium Microcystis aeruginosa and three common freshwater green algae Chlorella ellipsoidea, Chlorella vulgaris, and Scenedesmus quadricanda were exposed to UV-C irradiation at 0-200mJcm(-2) and subsequently incubated for 9-15 d under normal culture conditions. Cell density and cell integrity were assessed using flow cytometry. The results suggested that UV-C irradiation at 20-200mJcm(-2) can suppress M. aeruginosa growth for 3-13 d in a dose-dependent manner. UV-C irradiation at 20 and 50mJcm(-2) is sub-lethal to M. aeruginosa cells as over 80% of the exposed cells remained intact. However, UV-C irradiation at 100 and 200mJcm(-2) induced severe cell disintegration in more than 70% of the irradiated cells. Neither significant suppression nor disintegration effects on green algae were observed for UV-C irradiation at 20-200mJcm(-2) in this study. Taken together, the sensitivity of M. aeruginosa to UV-C irradiation was significantly higher than that of the non-toxic C. ellipsoidea, C. vulgaris, and S. quadricauda, suggesting the potential application of sub-lethal UV-C irradiation for M. aeruginosa bloom control with a predictable low ecological risk. PMID:20005556

  11. 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

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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

  3. Magnetite and Magnetotaxis in Algae

    PubMed Central

    de Araujo, F. F. Torres; Pires, M. A.; Frankel, R. B.; Bicudo, C. E. M.

    1986-01-01

    Magnetotactic algae of the genus Anisonema (Euglenophyceae) have been isolated from a coastal mangrove swamp in northeastern Brazil. The magnetotactic response is based on a permanent magnetic dipole moment per cell ∼7 10-10 emu. Each cell contains many magnetite (Fe3O4) particles organized in chains. ImagesFIGURE 2FIGURE 1FIGURE 3 PMID:19431684

  4. 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…

  5. 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.

  6. 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.

  7. “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

  8. [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

  9. 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.

  10. The Culture Collection of Algae and Protozoa (CCAP): a biological resource for protistan genomics.

    PubMed

    Gachon, Claire M M; Day, John G; Campbell, Christine N; Pröschold, Thomas; Saxon, Rachel J; Küpper, Frithjof C

    2007-12-30

    CCAP, the largest European protistan culture collection, is based at the Scottish Association for Marine Science near Oban, Scotland (http://www.ccap.ac.uk). The Collection comprises more than 2700 strains in the public domain, of which 1050 are marine algae, 1300 freshwater algae, and 350 protozoa. The primary mission of CCAP is to maintain and distribute defined cultures and their associated information to its customers. It also has a support and advisory function on all aspects of protistan science. In addition, it is involved in the training of students and researchers in algal identification and culture techniques. In light of the increasing number of fully sequenced protists, the CCAP is striving to provide targeted services and support to workers involved in all aspects of genomic research. At present, the Collection holds several hundred strains of genomic model taxa including: Acanthamoeba, Cafeteria, Cercomonas, Chlamydomonas, Chlorella, Cyanophora, Dictyostelium, Dunaliella, Ectocarpus, Emiliania, Euglena, Micromonas, Naegleria, Nephroselmis, Paramecium, Pavlova, Phaeodactylum, Porphyra, Pseudendoclonium, Pylaiella, Rhodomonas, Scenedesmus, Staurastrum, Tetrahymena, Thalassiosira, Volvox and Zygnema. These strains provide a defined representation of natural variation within model organisms, an increasingly useful resource for post-genomics approaches. Our aim over the next 2-5 years is to add value to the Collection by increasing the number of genome model species, and by offering an integrated, up-to-date, easy-to-use resource that would provide curated information on our strain holdings. In collaboration with other major Biological Resource Centres worldwide, we intend to build a hub providing access to both protistan cultures and their associated bioinformatics data.

  11. 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.

  12. Algae control for hydrogeneration canals

    SciTech Connect

    Grahovac, P.

    1997-02-16

    The purpose of this Cooperative Research and Development Agreement (CRADA) was to assess and develop control practices for nuisance algae growth in power canal that delivers water to hydro-generation facilities. This growth results in expenditures related not only to lost generation but also labor and materials costs associated with implementing remediation procedures. On an industry-wide basis these costs associated with nuisance algal growth are estimated to be several million dollars per year.

  13. 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.

  14. 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%.

  15. 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

  16. 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

  17. Halogenated Compounds from Marine Algae

    PubMed Central

    Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

    2010-01-01

    Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds. PMID:20948909

  18. Uptake and toxicity of hexafluoroarsenate in aquatic organisms.

    PubMed

    Daus, Birgit; Weiss, Holger; Altenburger, Rolf

    2010-01-01

    The arsenic species hexafluoroarsenate has been described as a contaminant of surface waters of anthropogenic origin. Here, we undertake to identify the most sensitive biological receptor among several sentinel aquatic species used in eco-toxicological assessment and to understand toxicity in terms of internal dose. Therefore, a screening of short-term effects using different aquatic organisms (bacterium Vibrio fischeri, fish Danio rerio, crustacean Daphnia magna and green alga Desmodesmus subspicatus and Scenedesmus vacuolatus) was conducted. For most organisms tested, effects were not detectable even at very high hexafluoroarsenate concentrations (up to 9.6mM) and thus the ecotoxic potential was found to be low in comparison to other arsenic compounds. The only organisms showing a clear response were the unicellular green alga, e.g. S. vacuolatus with an EC(50) value of 1.12 mM (84 mg L(-1) As). A linear relationship between ambient and internal concentration was found for this organism with a slope of 1.63 x 10(-3). Therefore, the internal concentration which shows a significant effect, e.g. 20% of inhibition of reproduction, was found to occur at a relatively low internal dose of 0.98 microM. Moreover, no biotransformation products inside the algae could be detected using arsenic speciation analysis with HPLC-ICP-MS, thus biological effects must be attributed to the untransformed compound. We conclude that the very low uptake observed for hexafluoroarsenate may be interpreted as preventive against toxic effects for the organisms.

  19. 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.

  20. Effects of free Cu{sup 2+} and Zn{sup 2+} ions on growth and metal accumulation in freshwater algae

    SciTech Connect

    Knauer, K.; Behra, R.; Sigg, L.

    1997-02-01

    Five species of unicellular green algae were exposed to a broad range of Cu{sup 2+} and Zn{sup 2+} concentrations to examine the relationship between the free Cu{sup 2+} and Zn{sup 2+} ion concentrations and algal growth at metal concentrations relevant for freshwater phytoplankton. The authors estimated extra- and intracellular metal concentrations and characterized the adsorption of copper and zinc on algal surfaces. The optimal growth rate of Scenedesmus subspicatus occurred in a broad range of Cu{sup 2+} and Zn{sup 2+} concentrations (from 10{sup {minus}15} to 10{sup {minus}7} and from 10{sup {minus}12} to 10{sup {minus}55} M, respectively). Chlamydomonas reinhardtii reacted more sensitively toward copper, optimal growth was achieved only at a pCu (= {minus}log[Cu{sup 2+}]) around 11, whereas growth was optimal over about three orders of magnitude of the free Cu{sup 2+} concentration (from 10{sup {minus}13} to 10{sup {minus}10} M). Chlamydomonas cultures isolated from Lake Constance tolerated Cu{sup 2+} concentrations over seven orders of magnitude (pCu = 7 to 14). The growth of algae showed a high tolerance toward high intracellular copper and zinc concentrations. This suggests that the cells may immobilize the metals intracellularly. The affinity of copper for algal surfaces is higher than that of zinc in the experimental concentration range: adsorption constants log K{sub Cu} (11.06) > log K{sub Zn} (6.49) (pH = 7.9). These freshwater algae tolerate higher Cu{sup 2+} and Zn{sup 2+} concentrations than marine algal species. In comparison to the lake data, the results obtained from the culture algae indicate a possible role for copper as a limiting factor for certain algal species in eutrophic lakes.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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)

  6. 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.…

  7. 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.

  8. Antarctic sea ice thickness affects algae populations

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-01-01

    In the waters off Antarctica, algae grow and live in the sea ice that surrounds the southern continent—a floating habitat sure to change as the planet warms. As with most aquatic ecosystems, microscopic algae form the base of the Southern Ocean food web. Distinct algae populations reside in the sea ice surface layers, on the ice's underside, and within the floating ice itself. The algae that reside on the floating ice's underside are particularly important for the region's krill population, while those on the interior or surface layers are less accessible. Understanding how changing sea ice properties will affect the regional biology, then, depends on understanding how algae populations interact with the ice.

  9. The ice nucleation activity of extremophilic algae.

    PubMed

    Kviderova, Jana; Hajek, Josef; Worland, Roger M

    2013-01-01

    Differences in the level of cold acclimation and cryoprotection estimated as ice nucleation activity in snow algae (Chlamydomonas cf. nivalis and Chloromonas nivalis), lichen symbiotic algae (Trebouxia asymmetrica, Trebouxia erici and Trebouxia glomerata), and a mesophilic strain (Chlamydomonas reinhardti) were evaluated. Ice nucleation activity was measured using the freezing droplet method. Measurements were performed using suspensions of cells of A750 (absorbance at 750 nm) ~ 1, 0.1, 0.01 and 0.001 dilutions for each strain. The algae had lower ice nucleation activity, with the exception of Chloromonas nivalis contaminated by bacteria. The supercooling points of the snow algae were higher than those of lichen photobionts. The supercooling points of both, mesophilic and snow Chlamydomonas strains were similar. The lower freezing temperatures of the lichen algae may reflect either the more extreme and more variable environmental conditions of the original localities or the different cellular structure of the strains examined.

  10. 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.

  11. 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.

  12. Algae inhibition experiment and load characteristics of the algae solution

    NASA Astrophysics Data System (ADS)

    Xiong, L.; Gao, J. X.; Zhang, Y. X.; Yang, Z. K.; Zhang, D. Q.; He, W.

    2016-08-01

    It is necessary to inhibit microbial growth in an industrial cooling water system. This paper has developed a Monopolar/Bipolar polarity high voltage pulser with load adaptability for an algal experimental study. The load characteristics of the Chlorella pyrenoidosa solution were examined, and it was found that the solution load is resistive. The resistance is related to the plate area, concentration, and temperature of the solution. Furthermore, the pulser's treatment actually inhibits the algae cell growth. This article also explores the influence of various parameters of electric pulses on the algal effect. After the experiment, the optimum pulse parameters were determined to be an electric field intensity of 750 V/cm, a pulse width per second of 120μs, and monopolar polarity.

  13. Microbodies of the alga Chara.

    PubMed

    Stabenau, Helmut; Säftel, Werner; Winkler, Uwe

    2003-05-01

    Chara fragilis possesses microbodies with a remarkably large size of up to 2 micro m in diameter. Many of the organelles contain huge nucleoids of amorphous material or paracrystalline inclusions. After isolation of the organelles by gradient centrifugation the specific density of the microbodies was determined to be 1.25 g cm-3. Catalase, glycolate oxidase and hydroxypyruvate reductase as well as enzymes of the fatty acid beta-oxidation pathway were demonstrated to be constituents of the microbodies in Chara indicating that they are similar to those in green leaves. The data obtained are in agreement with the view that the Charophyceae and especially the algae in the subgroup of Charales are very closely related to the land plants.

  14. 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

  15. DGDG and Glycolipids in Plants and Algae.

    PubMed

    Kalisch, Barbara; Dörmann, Peter; Hölzl, Georg

    2016-01-01

    Photosynthetic organelles in plants and algae are characterized by the high abundance of glycolipids, including the galactolipids mono- and digalactosyldiacylglycerol (MGDG, DGDG) and the sulfolipid sulfoquinovosyldiacylglycerol (SQDG). Glycolipids are crucial to maintain an optimal efficiency of photosynthesis. During phosphate limitation, the amounts of DGDG and SQDG increase in the plastids of plants, and DGDG is exported to extraplastidial membranes to replace phospholipids. Algae often use betaine lipids as surrogate for phospholipids. Glucuronosyldiacylglycerol (GlcADG) is a further glycolipid that accumulates under phosphate deprived conditions. In contrast to plants, a number of eukaryotic algae contain very long chain polyunsaturated fatty acids of 20 or more carbon atoms in their glycolipids. The pathways and genes for galactolipid and sulfolipid synthesis are largely conserved between plants, Chlorophyta, Rhodophyta and algae with complex plastids derived from secondary or tertiary endosymbiosis. However, the relative contribution of the endoplasmic reticulum- and plastid-derived lipid pathways for glycolipid synthesis varies between plants and algae. The genes for glycolipid synthesis encode precursor proteins imported into the photosynthetic organelles. While most eukaryotic algae contain the plant-like galactolipid (MGD1, DGD1) and sulfolipid (SQD1, SQD2) synthases, the red alga Cyanidioschyzon harbors a cyanobacterium-type DGDG synthase (DgdA), and the amoeba Paulinella, derived from a more recent endosymbiosis event, contains cyanobacterium-type enzymes for MGDG and DGDG synthesis (MgdA, MgdE, DgdA). PMID:27023231

  16. 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.

  17. DGDG and Glycolipids in Plants and Algae.

    PubMed

    Kalisch, Barbara; Dörmann, Peter; Hölzl, Georg

    2016-01-01

    Photosynthetic organelles in plants and algae are characterized by the high abundance of glycolipids, including the galactolipids mono- and digalactosyldiacylglycerol (MGDG, DGDG) and the sulfolipid sulfoquinovosyldiacylglycerol (SQDG). Glycolipids are crucial to maintain an optimal efficiency of photosynthesis. During phosphate limitation, the amounts of DGDG and SQDG increase in the plastids of plants, and DGDG is exported to extraplastidial membranes to replace phospholipids. Algae often use betaine lipids as surrogate for phospholipids. Glucuronosyldiacylglycerol (GlcADG) is a further glycolipid that accumulates under phosphate deprived conditions. In contrast to plants, a number of eukaryotic algae contain very long chain polyunsaturated fatty acids of 20 or more carbon atoms in their glycolipids. The pathways and genes for galactolipid and sulfolipid synthesis are largely conserved between plants, Chlorophyta, Rhodophyta and algae with complex plastids derived from secondary or tertiary endosymbiosis. However, the relative contribution of the endoplasmic reticulum- and plastid-derived lipid pathways for glycolipid synthesis varies between plants and algae. The genes for glycolipid synthesis encode precursor proteins imported into the photosynthetic organelles. While most eukaryotic algae contain the plant-like galactolipid (MGD1, DGD1) and sulfolipid (SQD1, SQD2) synthases, the red alga Cyanidioschyzon harbors a cyanobacterium-type DGDG synthase (DgdA), and the amoeba Paulinella, derived from a more recent endosymbiosis event, contains cyanobacterium-type enzymes for MGDG and DGDG synthesis (MgdA, MgdE, DgdA).

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

    PubMed

    Wu, Hongqin; Miao, Xiaoling

    2014-10-01

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

  19. 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

  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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Effects of nitrogen source and concentration on biomass and oil production of a Scenedesmus rubescens like microalga.

    PubMed

    Lin, Qiang; Lin, Junda

    2011-01-01

    This investigation examined the effects of nitrogen source and concentration on the ash free dry biomass (AFDB) and oil accumulation and productivity of a Scenedesmusrubescens like alga cultivated in indoor photo-bioreactors and outdoor raceway ponds. Among the nitrogen sources ((NH4)2CO3, urea, NaNO3, urea and NaNO3 mixture), the algae fed with the mixture of urea-N and NaNO3-N had the highest AFDB productivity of 0.539±0.040 g/L/d and the content of fatty acid methyl esters (FAME) (%) fed with (NH4)2CO3-N increased continuously for 17 days and reached 42.94±2.05% in the indoor photo-bioreactors. The content of C18 series (as % of total FAME) was high in all the treatments of nitrogen sources. The algae fed with (NH4)2CO3-N had the highest FAME productivity of 0.133 g/L/d (P<0.001). The effect of ammonia concentration on the AFDB and FAME productivity was also studied during the 20-day cultivation in the outdoor raceway cultivation system. The mean FAME of the algae cultivated in the ammonia concentration of 1.0-1.5 mg/L were the highest (0.556±0.112 g/m2/d) (P<0.001). The total Kjeldahl nitrogen (TKN) in the algae and cultivation water decreased but the FAME content (%) of the algae increased during the nitrogen starvation phase.

  7. 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

  8. Metagenome survey of a multispecies and alga-associated biofilm revealed key elements of bacterial-algal interactions in photobioreactors.

    PubMed

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

    2013-10-01

    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.

  9. 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

  10. Method and apparatus for processing algae

    SciTech Connect

    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.

  11. 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...

  12. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 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...

  13. 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...

  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, 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...

  16. Ecotoxicity evaluation of selected sulfonamides.

    PubMed

    Białk-Bielińska, Anna; Stolte, Stefan; Arning, Jürgen; Uebers, Ute; Böschen, Andrea; Stepnowski, Piotr; Matzke, Marianne

    2011-10-01

    Sulfonamides (SAs) are a group of antibiotic drugs widely used in veterinary medicine. The contamination of the environment by these pharmaceuticals has raised concern in recent years. However, knowledge of their (eco)toxicity is still very basic and is restricted to just a few of these substances. Even though their toxicological analysis has been thoroughly performed and ecotoxicological data are available in the literature, a systematic analysis of their ecotoxicological potential has yet to be carried out. To fill this gap, 12 different SAs were chosen for detailed analysis with the focus on different bacteria as well as non-target organisms (algae and plants). A flexible (eco)toxicological test battery was used, including enzymes (acetylcholinesterase and glutathione reductase), luminescent marine bacteria (Vibrio fischeri), soil bacteria (Arthrobacter globiformis), limnic unicellular green algae (Scenedesmus vacuolatus) and duckweed (Lemna minor), in order to take into account both the aquatic and terrestrial compartments of the environment, as well as different trophic levels. It was found that SAs are not only toxic towards green algae (EC₅₀=1.54-32.25 mg L⁻¹) but have even stronger adverse effect on duckweed (EC₅₀=0.02-4.89 mg L⁻¹) than atrazine - herbicide (EC₅₀=2.59 mg L⁻¹). PMID:21752420

  17. 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.

  18. 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.

  19. 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)

  20. 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.

  1. 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

  2. Carotenoids in algae: distributions, biosyntheses and functions.

    PubMed

    Takaichi, Shinichi

    2011-01-01

    For photosynthesis, phototrophic organisms necessarily synthesize not only chlorophylls but also carotenoids. Many kinds of carotenoids are found in algae and, recently, taxonomic studies of algae have been developed. In this review, the relationship between the distribution of carotenoids and the phylogeny of oxygenic phototrophs in sea and fresh water, including cyanobacteria, red algae, brown algae and green algae, is summarized. These phototrophs contain division- or class-specific carotenoids, such as fucoxanthin, peridinin and siphonaxanthin. The distribution of α-carotene and its derivatives, such as lutein, loroxanthin and siphonaxanthin, are limited to divisions of Rhodophyta (macrophytic type), Cryptophyta, Euglenophyta, Chlorarachniophyta and Chlorophyta. In addition, carotenogenesis pathways are discussed based on the chemical structures of carotenoids and known characteristics of carotenogenesis enzymes in other organisms; genes and enzymes for carotenogenesis in algae are not yet known. Most carotenoids bind to membrane-bound pigment-protein complexes, such as reaction center, light-harvesting and cytochrome b(6)f complexes. Water-soluble peridinin-chlorophyll a-protein (PCP) and orange carotenoid protein (OCP) are also established. Some functions of carotenoids in photosynthesis are also briefly summarized.

  3. 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.

  4. SCALE FORMATION IN CHRYSOPHYCEAN ALGAE

    PubMed Central

    Brown, R. Malcolm; Franke, Werner W.; Kleinig, Hans; Falk, Heinz; Sitte, Peter

    1970-01-01

    The cell wall of the marine chrysophycean alga Pleurochrysis scherfellii is composed of distinct wall fragments embedded in a gelatinous mass. The latter is a polysaccharide of pectic character which is rich in galactose and ribose. These wall fragments are identified as scales. They have been isolated and purified from the vegetative mother cell walls after zoospore formation. Their ultrastructure is described in an electron microscope study combining sectioning, freeze-etch, and negative staining techniques. The scales consist of a layer of concentrically arranged microfibrils (ribbons with cross-sections of 12 to 25 x 25 to 40 A) and underlying radial fibrils of similar dimensions. Such a network-plate is densely coated with particles which are assumed to be identical to the pectic component. The microfibrils are resistant to strong alkaline treatment and have been identified as cellulose by different methods, including sugar analysis after total hydrolysis, proton resonance spectroscopical examination (NMR spectroscopy) of the benzoylated product, and diverse histochemical tests. The formation and secretion of the scales can be followed along the maturing Golgi cisternae starting from a pronounced dilated "polymerization center" as a completely intracisternal process which ends in the exocytotic extrusion of the scales. The scales reveal the very same ultrastructure within the Golgi cisternae as they do in the cell wall. The present finding represents the first evidence on cellulose formation by the Golgi apparatus and is discussed in relation to a basic scheme for cellulose synthesis in plant cells in general. PMID:5513606

  5. 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.

  6. Biofixation of carbon dioxide by Spirulina sp. and Scenedesmus obliquus cultivated in a three-stage serial tubular photobioreactor.

    PubMed

    de Morais, Michele Greque; Costa, Jorge Alberto Vieira

    2007-05-01

    The increase in the concentration of atmospheric carbon dioxide is considered to be one of the main causes of global warming. As estimated by the Intergovernmental Panel on Climate Change (IPCC) criteria, about 10-15% of the gases emitted from the combustion coal being in the form of carbon dioxide. Microalgae and cyanobacteria can contribute to the reduction of atmospheric carbon dioxide by using this gas as carbon source. We cultivated the Scenedesmus obliquus and Spirulina sp. at 30 degrees C in a temperature-controlled three-stage serial tubular photobioreactor and determined the resistance of these organisms to limitation and excess of carbon dioxide and the capacity of the system to fix this greenhouse gas. After 5 days of cultivation under conditions of carbon limitation both organisms showed cell death. Spirulina sp. presenting better results for all parameters than S. obliquus. For Spirulina sp. the maximum specific growth rate and maximum productivity was 0.44 d(-1), 0.22 g L(-1)d(-1), both with 6% (v/v) carbon dioxide and maximum cellular concentration was 3.50 g L(-1) with 12% (v/v) carbon dioxide. Maximum daily carbon dioxide biofixation was 53.29% for 6% (v/v) carbon dioxide and 45.61% for 12% carbon dioxide to Spirulina sp. corresponding values for S. obliquus being 28.08% for 6% (v/v) carbon dioxide and 13.56% for 12% (v/v) carbon dioxide. The highest mean carbon dioxide fixation rates value was 37.9% to Spirulina sp. in the 6% carbon dioxide runs.

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

    PubMed Central

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

    2016-01-01

    Snow algae and green algae living in aeroterrestrial habitats are ideal obbjects 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 charopyhte green algae (Zygnema sp., Zygogonium ericetorum and Klebsormidium crenulatum). The hyperspectral microscopic mapping and imaging technique allowed us to acquire total absorbance spectra of these microalgae in the waveband of 400-900 nm. Particularly in Chlamydomonas nivalis and Chlainomonas sp., a high absorbance in the wave band of 400-550 nm was observed, due to naturally occurring secondary carotenoids; in Chloromonas sp. and in the charopyhte algae this 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 not change the spectral properties, in the charopyhte algae the condensation of the cytoplasm and plastids increased the absorbance in the lower waveband of 400 – 500 nm. 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

  8. 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

  9. 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.

  10. PPR proteins of green algae.

    PubMed

    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.

  11. 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

  12. [Algae removal of high algae raw water by coagulation enhanced by ozonation].

    PubMed

    Liu, Hai-Long; Yang, Dong; Zhao, Zhi-Yong; Li, Zheng-Jian; Cheng, Fang-Qin

    2009-07-15

    Apparent molecular weight distribution (AMWD) and resin fractionation were used to characterize organic matters of the raw water. Removal of algae, change and removal of dissolved organic carbon (DOC), disinfection by products (DBPs) control during the preozonation enhanced coagulation treatments in the jar-scale and pilot-scale experiment were studied. Algae activity (AA) was measured and used to elucidate the mechanisms of algae removal by above treatments. Results show that algae removal can be improved distinctively by proper preozonation, as the ozone dose 1.0 mg x L(-1), for instance. Algae removal could be increased from 55%-85% by traditional coagulation to 95% by enhanced coagulation after preozonation; and the best removal achieved 99.3% with ozone 1.0 mg x L(-1) and PACl 3.0 mg x L(-1); the residual THMFP (Trihalomethanes formation potential) was lowered from 117 microg x L(-1) by traditional coagulation to 46 microg x L(-1). But higher dose of ozone (as > or = 2.0 mg x L(-1)) impairs organic matter removal, although it decreases algae activity further. Significant differences were found in algae removal by AA detection between ozonation and traditional coagulation. Traditional coagulation had little effect on AA no matter the different PAC1 doses; while AA decreased clearly after ozonation. AA was lowered below 12 under 0.5-2.0 mg x L(-1) ozonation; and it kept decreasing with increase of ozone dosage. During the following coagulation, coagulant or some of its hydrolysised components enhanced the AA decrease by ozonation. Compared to the method of normal microscopy counting, AA test expresses the influence of algae living state by water treatment processes more clearly; which would provide treatment process designer with more distinct information about algae removal mechanisms and how to arrange the treatment processes to improve algae removal.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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

  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.

  2. Selection and evaluation of CO2 tolerant indigenous microalga Scenedesmus dimorphus for unsaturated fatty acid rich lipid production under different culture conditions.

    PubMed

    Vidyashankar, S; Deviprasad, K; Chauhan, V S; Ravishankar, G A; Sarada, R

    2013-09-01

    Five indigenous microalgal strains of Scenedesmus, Chlorococcum, Coelastrum, and Ankistrodesmus genera, isolated from Indian fresh water habitats, were studied for carbon-dioxide tolerance and its effect on growth, lipid and fatty acid profile. Scenedesmus dimorphus strain showed maximum growth (1.5 g/L) and lipid content (17.83% w/w) under CO2 supplementation, hence selected for detailed evaluation. The selected strain was alkaline adapted but tolerated (i) wide range of pH (5-11); (ii) elevated salinity levels (up to 100 mM, NaCl) with low biomass yields and increased carotenoids (19.34 mg/g biomass); (iii) elevated CO2 levels up to 15% v/v with enhancement in specific growth rate (0.137 d(-1)), biomass yield (1.57 g/L), lipid content (19.6% w/w) and CO2 biofixation rate (0.174 g L(-1) d(-1)). Unsaturated fatty acid content (alpha linolenic acid) increased with CO2 supplementation in the strain.

  3. 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.

  4. 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.

  5. Genome of the red alga Porphyridium purpureum

    PubMed Central

    Bhattacharya, Debashish; Price, Dana C.; Xin Chan, Cheong; Qiu, Huan; Rose, Nicholas; Ball, Steven; Weber, Andreas P. M.; Cecilia Arias, Maria; 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

  6. Turning Algae into Energy in New Mexico

    ScienceCinema

    Sayre, Richard; Olivares, Jose; Lammers, Peter

    2016-07-12

    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.

  7. 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.

  8. Microspectroscopy of the photosynthetic compartment of algae.

    PubMed

    Evangelista, Valtere; Frassanito, Anna Maria; Passarelli, Vincenzo; Barsanti, Laura; Gualtieri, Paolo

    2006-01-01

    We performed microspectroscopic evaluation of the pigment composition of the photosynthetic compartments of algae belonging to different taxonomic divisions and higher plants. The feasibility of microspectroscopy for discriminating among species and/or phylogenetic groups was tested on laboratory cultures. Gaussian bands decompositions and a fitting algorithm, together with fourth-derivative transformation of absorbance spectra, provided a reliable discrimination among chlorophylls a, b and c, phycobiliproteins and carotenoids. Comparative analysis of absorption spectra highlighted the evolutionary grouping of the algae into three main lineages in accordance with the most recent endosymbiotic theories.

  9. Effects of DDT and dicofol on population growth of Brachionus calyciflorus under different algal (Scenedesmus obliquus) densities.

    PubMed

    Xu, Xiao-Ping; Xi, Yi-Long; Chu, Zhao-Xia; Xiang, Xian-Ling

    2014-09-01

    A number of organochlorine pesticides, including DDT and dicofol, used to be important in crop protection and management. Their residues may reach water bodies and eventually affect the non-target organisms such as rotifers. In the present study, we evaluated the effects of DDT (0.05, 0.1, 0.2 and 0.4 mg l(-1)) and dicofol (0.1, 0.2, 0.4 and 0.8 mg l(-1)) on the population growth of rotifer Brachionus calyciflorus under two levels of Scenedesmus obliquus (1.0 x 10(6) and 3.0 x 10(6) cell ml(-1)). Regardless of the food level, DDT was more toxic than dicofol to B. calyciflorus. Under low food level, DDT at 0.1 and 0.2 mg l(-1) decreased the population growth rate (r), and DDT at 0.05-0.4 mg l(-1) decreased the maximum population density (K). Dicofol at 0.4 and 0.8 mg l(-1) decreased r and K, but dicofol at 0.2 mg l(-1) increased K. Under high food level, DDT at 0.05-0.2 mg l(-1) increased K, whereas DDT at 0.4 mg l(-1) as well as dicofol at 0.4 and 0.8 mg l(-1) decreased r and K. Increase in food level increased r exposed to DDT at 0.05-0.2 mg l(-1) as well as dicofol at 0.8 mg l(-1), and Kexposed to DDTat 0.05-0.2 mg l(-1) as well as dicofol at 0.1 and 0.2 mg l(-1). DDT concentration, algal density and their interaction affected r and K of B. calyciflorus. Both dicofol concentration and algal density affected r. Dicofol concentration, algal density and their interaction affected K. Both r and K were suitable endpoints for assessing the effects of DDT and dicofol on the rotifers population dynamics under two algal densities, and the latter was more sensitive.

  10. 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...

  11. MANOMETRIC MEASUREMENTS OF PHOTOSYNTHESIS IN THE MARINE ALGA GIGARTINA

    PubMed Central

    Emerson, Robert; Green, Lowell

    1934-01-01

    A manometric method for measuring photosynthesis in marine algae is described. Photosynthesis in the red alga Gigartina harveyana is shown to be similar in all important respects to photosynthesis in Chlorella and other Chlorophyceae. PMID:19872816

  12. 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)...

  13. [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.

  14. [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

  15. 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)

  16. Neonatal sepsis caused by Shewanella algae: A case report.

    PubMed

    Charles, Marie Victor Pravin; Srirangaraj, Sreenivasan; Kali, Arunava

    2015-01-01

    Sepsis remains a leading cause of mortality among neonates, especially in developing countries. Most cases of neonatal sepsis are attributed to Escherichia coli and other members of the Enterobacteriaceae family. Shewanella algae (S. algae) is a gram-negative saprophytic bacillus, commonly associated with the marine environment, which has been isolated from humans. Early onset neonatal sepsis caused by S. algae is uncommon. We report a case of S. algae blood stream infection in a newborn with early onset neonatal sepsis.

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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…

  3. Research and development for algae-based technologies in Korea: a review of algae biofuel production.

    PubMed

    Hong, Ji Won; Jo, Seung-Woo; Yoon, Ho-Sung

    2015-03-01

    This review covers recent research and development (R&D) activities in the field of algae-based biofuels in Korea. As South Korea's energy policy paradigm has focused on the development of green energies, the government has funded several algae biofuel R&D consortia and pilot projects. Three major programs have been launched since 2009, and significant efforts are now being made to ensure a sustainable supply of algae-based biofuels. If these R&D projects are executed as planned for the next 10 years, they will enable us to overcome many technical barriers in algae biofuel technologies and help Korea to become one of the leading countries in green energy by 2020.

  4. 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)

  5. 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.

  6. Pheromone signaling during sexual reproduction in algae.

    PubMed

    Frenkel, Johannes; Vyverman, Wim; Pohnert, Georg

    2014-08-01

    Algae are found in all aquatic and many terrestrial habitats. They are dominant in phytoplankton and biofilms thereby contributing massively to global primary production. Since algae comprise photosynthetic representatives of the various protoctist groups their physiology and appearance is highly diverse. This diversity is also mirrored in their characteristic life cycles that exhibit various facets of ploidy and duration of the asexual phase as well as gamete morphology. Nevertheless, sexual reproduction in unicellular and colonial algae usually has as common motive that two specialized, sexually compatible haploid gametes establish physical contact and fuse. To guarantee mating success, processes during sexual reproduction are highly synchronized and regulated. This review focuses on sex pheromones of algae that play a key role in these processes. Especially, the diversity of sexual strategies as well as of the compounds involved are the focus of this contribution. Discoveries connected to algal pheromone chemistry shed light on the role of key evolutionary processes, including endosymbiotic events and lateral gene transfer, speciation and adaptation at all phylogenetic levels. But progress in this field might also in the future provide valid tools for the manipulation of aquaculture and environmental processes.

  7. 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.

  8. Peroxisomal targeting signals in green algae.

    PubMed

    Shinozaki, Akiko; Sato, Nagisa; Hayashi, Yasuko

    2009-03-01

    Peroxisomal enzymatic proteins contain targeting signals (PTS) to enable their import into peroxisomes. These targeting signals have been identified as PTS1 and PTS2 in mammalian, yeast, and higher plant cells; however, no PTS2-like amino acid sequences have been observed in enzymes from the genome database of Cyanidiochyzon merolae (Bangiophyceae), a primitive red algae. In studies on the evolution of PTS, it is important to know when their sequences came to be the peroxisomal targeting signals for all living organisms. To this end, we identified a number of genes in the genome database of the green algae Chlamydomonas reinhardtii, which contains amino acid sequences similar to those found in plant PTS. In order to determine whether these sequences function as PTS in green algae, we expressed modified green fluorescent proteins (GFP) fused to these putative PTS peptides under the cauliflower mosaic virus 35S promoter. To confirm whether granular structures containing GFP-PTS fusion proteins accumulated in the peroxisomes of Closterium ehrenbergii, we observed these cells after the peroxisomes were stained with 3, 3'-diaminobenzidine. Our results confirm that the GFP-PTS fusion proteins indeed accumulated in the peroxisomes of these green algae. These findings suggest that the peroxisomal transport system for PTS1 and PTS2 is conserved in green algal cells and that our fusion proteins can be used to visualize peroxisomes in live cells.

  9. Three dimensional quantitative structure-toxicity relationship modeling and prediction of acute toxicity for organic contaminants to algae.

    PubMed

    Jin, Xiangqin; Jin, Minghao; Sheng, Lianxi

    2014-08-01

    Although numerous chemicals have been identified to have significant toxicological effect on aquatic organisms, there is still lack of a reliable, high-throughput approach to evaluate, screen and monitor the presence of organic contaminants in aquatic system. In the current study, we proposed a synthetic pipeline to automatically model and predict the acute toxicity of chemicals to algae. In the procedure, a new alignment-free three dimensional (3D) structure characterization method was described and, with this method, several 3D-quantitative structure-toxicity relationship (3D-QSTR) models were developed, from which two were found to exhibit strong internal fitting ability and high external predictive power. The best model was established by Gaussian process (GP), which was further employed to perform extrapolation on a random compound library consisting of 1014 virtually generated substituted benzenes. It was found that (i) substitution number can only exert slight influence on chemical׳s toxicity, but low-substituted benzenes seem to have higher toxicity than those of high-substituted entities, and (ii) benzenes substituted by nitro group and halogens exhibit high acute toxicity as compared to other substituents such as methyl and carboxyl groups. Subsequently, several promising candidates suggested by computational prediction were assayed by using a standard algal growth inhibition test. Consequently, four substituted benzenes, namely 2,3-dinitrophenol, 2-chloro-4-nitroaniline, 1,2,3-trinitrobenzene and 3-bromophenol, were determined to have high acute toxicity to Scenedesmus obliquus, with their EC50 values of 2.5±0.8, 10.5±2.1, 1.4±0.2 and 42.7±5.4μmol/L, respectively. PMID:24960624

  10. 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

  11. 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.

  12. Uptake and Loss of Na+, Rb+, and Cs+ in Relation to an Active Mechanism for Extrusion of Na+ in Scenedesmus 1

    PubMed Central

    Kylin, Anders

    1966-01-01

    The mechanism for extrusion of Na+ from Scenedesmus cells is characterized physiologically. It is stimulated by phosphate but oxygen is not necessary. Rb+ and Cs+ may also be extruded, but in the presence of Na+ they cannot compete for the sites on the inside of the transport system. When Na+ is extruded, Rb+ and, by inference, K+ seems to be transported as counter ion from the outside, and sodium ions compete only weakly for this external site. The parallelism between these findings and the Na+-K+-activated adenosine triphosphatases known from animal tissues is pointed out. With low additions of phosphate, the extrusion mechanism can keep the cells practically free from Na+. Increasing the concentrations of external phosphate stimulates uptake more than extrusion, and a net uptake occurs. As for Rb+ and Cs+, they are taken up in the absence of external phosphate, but additions of P will greatly enhance the amounts absorbed. Two different ways of uptake are indicated. PMID:5932402

  13. Widespread occurrence of norspermidine and norspermine in eukaryotic algae.

    PubMed

    Hamana, K; Matsuzaki, S

    1982-04-01

    Seven phyla of eukaryotic algae were analyzed to determine their contents of diamines and polyamines. The algae examined included Rhodophyta, Pyrrophyta, Chrysophyta, Phaeophyta, Euglenophyta, Chlorophyta, and Charophyta. Both putrescine and spermidine were detected in all the algae studied, while appreciable amounts of spermine were detected only in a few species of algae. 1,3-Diaminopropane, norspermidine, and norspermine, which are chemical analogs of putrescine, spermidine, and spermine, respectively, were widely distributed in various species of algae. There was no parallelism between the distribution patterns of putrescine derivatives and those of 1,3-diaminopropane derivatives. Cadaverine and agmatine were detected in multicellular marine algae. Homospermidine was detected sporadically in some algae. The biological and phylogenetical significance of polyamines in these lower eukaryotes is discussed.

  14. Sulfated polysaccharides as bioactive agents from marine algae.

    PubMed

    Ngo, Dai-Hung; Kim, Se-Kwon

    2013-11-01

    Recently, much attention has been paid by consumers toward natural bioactive compounds as functional ingredients in nutraceuticals. Marine algae are considered as valuable sources of structurally diverse bioactive compounds. Marine algae are rich in sulfated polysaccharides (SPs) such as carrageenans in red algae, fucoidans in brown algae and ulvans in green algae. These SPs exhibit many health beneficial nutraceutical effects such as antioxidant, anti-allergic, anti-human immunodeficiency virus, anticancer and anticoagulant activities. Therefore, marine algae derived SPs have great potential to be further developed as medicinal food products or nutraceuticals in the food industry. This contribution presents an overview of nutraceutical effects and potential health benefits of SPs derived from marine algae.

  15. 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.

  16. Photooxidative Death in Blue-Green Algae

    PubMed Central

    Abeliovich, A.; Shilo, M.

    1972-01-01

    When incubated in the light under 100% oxygen, wild-type blue-green algae (Anacystis nidulans, Synechococcus cedrorum) die out rapidly at temperatures of 4 to 15 C, and at 35 C (or at 26 C in the case of S. cedrorum) in the absence of CO2. Photosynthesis is impaired in these cells long before they die. Blocking of photosystem II at high temperatures in the presence of CO2 sensitizes the algae to photooxidative death. Photooxidative death and bleaching of photosynthetic pigments are separable phenomena. Photooxidative conditions were demonstrated in Israeli fish ponds using A. nidulans as the test organism during dense summer blooms, when dissolved CO2 is low, and in winter, when water temperatures generally drop below 15 C. This finding suggests that photooxidative death may be responsible for the sudden decomposition of blue-green blooms in summer, and may be a factor in the absence of blue-green blooms in winter. PMID:4626540

  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. 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.

  19. 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).

  20. 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

  1. Nitrogenous wastewater treatment by activated algae

    SciTech Connect

    Gupta, S.K.

    1985-02-01

    A biological treatability study by activated algae process was performed with synthetic wastewater containing a high concentration of nitrogen. It was found that the wastewater could be processed at all nitrogen removal rates. The yield coefficient and decay coefficient for heterotrophic bacteria were 0.06 (COD basis) and 0.019 day/sup -1/ (COD bases) respectively. The yield coefficient and decay coefficient for nitrifiers were 0.06 and 0.02 day/sup -1/ respectively. NH/sup +//sub 4/-N seemed to inhibit bacteriological growth as the yield coefficients values were significantly lower. Nitrification was observed at all the nitrogen loadings. Diffusion of NH/sub 3/ into the atmosphere was the dominant mechanism of nitrogen removal. The results demonstrated a symbiotic relationship between algae and bacteria.

  2. Fermentation metabolism and its evolution in algae

    PubMed Central

    Catalanotti, Claudia; Yang, Wenqiang; Posewitz, Matthew C.; Grossman, Arthur R.

    2013-01-01

    Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume. PMID:23734158

  3. 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

  4. Fermentation metabolism and its evolution in algae.

    PubMed

    Catalanotti, Claudia; Yang, Wenqiang; Posewitz, Matthew C; Grossman, Arthur R

    2013-01-01

    Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume.

  5. 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).

  6. 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

  7. 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.

  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. 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

  10. 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

  11. 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.

  12. 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

  13. Microplate Technique for Determining Accumulation of Metals by Algae

    PubMed Central

    Hassett, James M.; Jennett, J. Charles; Smith, James E.

    1981-01-01

    A microplate technique was developed to determine the conditions under which pure cultures of algae removed heavy metals from aqueous solutions. Variables investigated included algal species and strain, culture age (11 and 44 days), metal (mercury, lead, cadmium, and zinc), pH, effects of different buffer solutions, and time of exposure. Plastic, U-bottomed microtiter plates were used in conjunction with heavy metal radionuclides to determine concentration factors for metal-alga combinations. The technique developed was rapid, statistically reliable, and economical of materials and cells. Results (expressed as concentration factors) were in reasonably good agreement with literature values. All species of algae studied removed mercury from solution. Green algae proved better at accumulating cadmium than did blue-green algae. No alga studied removed zinc, perhaps because cells were maintained in the dark during the labeling period. Chlamydomonas sp. proved superior in ability to remove lead from solution. PMID:16345764

  14. 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.

  15. 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.

  16. 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.

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

    ScienceCinema

    Elliott, Doug

    2016-07-12

    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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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...

  6. [THE MICROSCOPIC ALGAE AS HUMAN PATHOGENS].

    PubMed

    Roman, Manuel Casal

    2014-01-01

    Some microscopic algae can cause different infectious diseases in humans, including skin, bone, and disseminated. These little-known emerging disease are more severe in immunocompromised patients. The confirmatory microbiological diagnosis must be done differential with yeast-like fungi that can be confused. Anti-fungal drugs and surgery, being quite frequent treatment failure have been used in the treatment. Given the increase of immunosuppression in the current medicine and new possibilities of microbiological diagnostics, it is logical that these diseases tend to increase, by which all physician should know them. PMID:27386675

  7. 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

  8. [THE MICROSCOPIC ALGAE AS HUMAN PATHOGENS].

    PubMed

    Roman, Manuel Casal

    2014-01-01

    Some microscopic algae can cause different infectious diseases in humans, including skin, bone, and disseminated. These little-known emerging disease are more severe in immunocompromised patients. The confirmatory microbiological diagnosis must be done differential with yeast-like fungi that can be confused. Anti-fungal drugs and surgery, being quite frequent treatment failure have been used in the treatment. Given the increase of immunosuppression in the current medicine and new possibilities of microbiological diagnostics, it is logical that these diseases tend to increase, by which all physician should know them.

  9. 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.

  10. Effect-directed analysis of sediment-associated algal toxicants at selected hot spots in the river Elbe basin with a special focus on bioaccessibility.

    PubMed

    Schwab, Katrin; Altenburger, Rolf; Lübcke-von Varel, Urte; Streck, Georg; Brack, Werner

    2009-07-01

    Benthic algae are the dominant primary producers in many rivers and may be at risk of being affected by sediment-associated toxicants. Toxicity as well as bioaccessibility should be considered for the identification of major toxicants affecting benthic algae. Thus, effect-directed analysis (EDA) combining biotesting, fractionation, and chemical analysis was combined with both exhaustive and bioaccessibility-directed extraction to identify the major toxicants in sediments at three industrial sites in the Elbe River basin (Bitterfeld, Most, and Prelouc). Exhaustive accelerated solvent extraction was used together with bioaccessibility-directed extraction with TENAX in aqueous suspension. Growth inhibition of the green alga Scenedesmus vacuolatus identified polycyclic aromatic compounds as important algal toxicants at all three sites, while in Bitterfeld and Prelouc additional toxicants, such as N-phenyl-2-naphthylamine and 7H-benzo[de]anthracen-7-one, played an important role. Confirmation of the identified compounds was based on the index of confirmation quality (ICQ) comparing the effect of an artificial mixture to that of the original sample. The results suggest a successful confirmation of identified toxicants for most fractions with ICQ values between 0.5 and 2. The bioaccessibility of toxicants decreased in the order Prelouc > Bitterfeld > Most as determined by the investigation of TENAX samples. Similar total concentrations of toxicants in Prelouc and Most sediment result in bioaccessible concentrations in Prelouc that exceed those in Most by a factor of 10 to 20. The extraction with TENAX with a subsequent EDA proved to be a powerful tool for prioritizing contaminants and contaminated sites with respect to the hazard of sediment-associated toxicants to green algae. PMID:19228079

  11. Ammonia-nitrogen and orthophosphate removal by immobilized Scenedesmus sp. isolated from municipal wastewater for potential use in tertiary treatment.

    PubMed

    Zhang, Endong; Wang, Bing; Wang, Qihua; Zhang, Shubiao; Zhao, Budiao

    2008-06-01

    Scendesmus sp. isolated from municipal wastewater, entrapped in calcium alginate as algal sheets was employed to remove inorganic nutrients (N and P) from artificial and real domestic secondary effluents in parallel-plate bioreactor after starvation. The key factors affecting the removal efficiency (NH4+-N and PO4(3-)-P), system stability and reuse efficiency of screens were studied and discussed. It has been shown that cell density in the mixture of algal gel was the key factor compared with the thickness of the gel and the cell density of the reactor. A complete removal of NH4+-N and PO4(3-)-P was achieved within 4h of treatment in parallel bioreactors with the optimal cell density in the mixture of algal (2 x 10(8) algae mL(-1)) and 3mm gel sheets after second cycle. Nine cycles of wastewater treatment in 21 days were accomplished, holding higher removal efficiency. NH(4)(+)-N removal efficiency was 99.1% after 105 min, 100% after 135 min, PO4(3-)-P removal efficiency was 100% after 15 min in domestic secondary effluents. Immobilized Scendesmus sp. is shown to have great potentialities for removal of inorganic nitrogen and phosphorus from treated effluents.

  12. Identification of toxic products of anthracene photomodification in simulated sunlight.

    PubMed

    Brack, Werner; Altenburger, Rolf; Küster, Eberhard; Meissner, Bettina; Wenzel, Klaus-Dieter; Schüürmann, Gerrit

    2003-10-01

    Currently, the evidence of a rapid photomodification of anthracene under sunlight resulting in enhanced toxicity exists; however, the chemical causes of toxicity are still unknown. The present study aimed at filling this gap by irradiation of an anthracene suspension with simulated sunlight and subsequent effect-directed fractionation and analysis of toxic products with respect to the inhibition of bacterial energy metabolism of Vibrio fischeri, reproduction of the green algae Scenedesmus vacuolatus, and genotoxicity in the umuC test. Algal toxicity of anthracene was hardly modified by irradiation prior to testing and distributed over all fractions with emphasis on the fractions containing anthracene-9,10-dione and a photometabolite suggested to be 10-hydroxyanthrone. Bacterial toxicity and genotoxicity in contrast emerged only when anthracene was irradiated. Anthracene-1,4-dione, a so-far-unknown trace photometabolite, was identified as a very potent toxicant dominating the toxicity of photomodified anthracene to V. fischeri. In genotoxic fractions, 1-hydroxyanthracene-9,10-dione and 1,4-dihydroxyanthracene-9,10-dione were identified and confirmed as genotoxicants. The results stress the potential of effect-directed analysis approaches in contrast to mere chemical analysis in studies aiming at toxicologically relevant photomodified substances.

  13. Dynamics and environmental risk assessment of the herbicide glyphosate and its metabolite AMPA in a small vineyard river of the Lake Geneva catchment.

    PubMed

    Daouk, Silwan; Copin, Pierre-Jean; Rossi, Luca; Chèvre, Nathalie; Pfeifer, Hans-Rudolf

    2013-09-01

    The use of pesticides may lead to environmental problems, such as surface water pollution, with a risk for aquatic organisms. In the present study, a typical vineyard river of western Switzerland was first monitored to measure discharged loads, identify sources, and assess the dynamic of the herbicide glyphosate and its metabolite aminomethylphosphonic acid (AMPA). Second, based on river concentrations, an associated environmental risk was calculated using laboratory tests and ecotoxicity data from the literature. Measured concentrations confirmed the mobility of these molecules with elevated peaks during flood events, up to 4970 ng/L. From April 2011 to September 2011, a total load of 7.1 kg was calculated, with 85% coming from vineyards and minor urban sources and 15% from arable crops. Compared with the existing literature, this load represents an important fraction (6-12%) of the estimated amount applied because of the steep vineyard slopes (∼10%). The associated risk of these compounds toward aquatic species was found to be negligible in the present study, as well as for other rivers in Switzerland. A growth stimulation was nevertheless observed for the algae Scenedesmus vacuolatus with low concentrations of glyphosate, which could indicate a risk of perturbation in aquatic ecosystems, such as eutrophication. The combination of field and ecotoxicity data allowed the performance of a realistic risk assessment for glyphosate and AMPA, which should be applied to other pesticide molecules.

  14. Algae-based oral recombinant vaccines.

    PubMed

    Specht, Elizabeth A; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for "molecular pharming" in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered - from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity.

  15. 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

  16. 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.

  17. 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.

  18. Algae-based oral recombinant vaccines.

    PubMed

    Specht, Elizabeth A; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for "molecular pharming" in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered - from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity. PMID:24596570

  19. 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

  20. 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

  1. 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.

  2. Shewanella algae Peritonitis in Patients on Peritoneal Dialysis.

    PubMed

    Shanmuganathan, Malini; Goh, Bak Leong; Lim, Christopher; NorFadhlina, Zakaria; Fairol, Ibrahim

    Patients with peritonitis present with abdominal pain, diarrhea, fever, and turbid peritoneal dialysis (PD) fluid. Shewanella algae peritonitis has not yet been reported in PD patients in the literature. We present the first 2 cases of Shewanella algae peritonitis in PD patients. Mupirocin cream is applied on the exit site as prophylactic antibiotic therapy. PMID:27659933

  3. [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.

  4. 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.

  5. 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.

  6. 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.

  7. Effect of the temperature, pH and irradiance on the photosynthetic activity by Scenedesmus obtusiusculus under nitrogen replete and deplete conditions.

    PubMed

    Cabello, Juan; Toledo-Cervantes, Alma; Sánchez, León; Revah, Sergio; Morales, Marcia

    2015-04-01

    This paper evaluates the effect of the irradiance, pH and temperature on the photosynthetic activity (PA) of Scenedesmus obtusiusculus under N-replete and N-deplete conditions through oxygen measurements. The highest PA values were 160 mgO2 gb(-1) h(-1) at 620 μmol m(-2) s(-1), 35 °C and pH of 8 under N-replete conditions and 3.3 mgO2 gb(-1) h(-1) at 100 μmol m(-2) s(-1), 28.5 °C and pH of 5.5 for N-deplete conditions. Those operation conditions were tested in a flat-panel photobioreactor. The biomass productivity was 0.97 gb L(-1) d(-1) under N-replete conditions with a photosynthetic efficiency (PE) of 4.4% yielding 0.85 gb mol photon(-1). Similar biomass productivity was obtained under N-deplete condition; and the lipid productivity was 0.34 gL L(-1) d(-1) with a PE of 7.8% yielding 0.39 gL mol photon(-1). The apparent activation and deactivation energies were 16.1 and 30 kcal mol(-1), and 11.9 and 15.3 kcal mol(-1), for N-replete and N-deplete conditions, respectively. PMID:25647022

  8. 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

  9. 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

  10. Biodegradation of benzo(a)pyrene by two freshwater microalgae Selenastrum capricornutum and Scenedesmus acutus: a comparative study useful for bioremediation.

    PubMed

    García de Llasera, Martha Patricia; Olmos-Espejel, José de Jesús; Díaz-Flores, Gabriel; Montaño-Montiel, Adriana

    2016-02-01

    A comparative evaluation of the removal of benzo(a)pyrene (BaP) by sorption and degradation by two microalgal species, Selenastrum capricornutum and Scenedesmus acutus was performed. The monitoring of the amount of BaP remaining in the liquid culture media and the biomass along with the appearance of three metabolites (4,5 dihydrodiol-BaP; 7,8-dihydrodiol-BaP; and 9,10 dihydrodiol-BaP) at short time periods (from 0.25 to 72 h) in cultures exposed to BaP was made by high-performance liquid chromatography (HPLC) with fluorescence and UV detection. Complete removal of BaP was achieved by the two live microalgal species: S. capricornutum at 15 h of exposure (99%) and S. acutus at 72 h of exposure (95%). Sorption is an important phenomenon for BaP removal by S. capricornutum but biodegradation is the principal means of removing BaP in live cells. The formation of metabolites by S. capricornutum is rapid and seems to be proportional to the amount of the BaP added to cultures. In contrast, in these bioassays, most of the BaP removal of S. acutus is due to sorption rather than degradation. The appearance of metabolites in the cultures is very slow and at a low amount compared to cultures of S. capricornutum. The similarities and differences existing between the two microalgae are important for the establishment of the conditions for bioremediation.

  11. Mixotrophic cultivation of a microalga Scenedesmus obliquus in municipal wastewater supplemented with food wastewater and flue gas CO2 for biomass production.

    PubMed

    Ji, Min-Kyu; Yun, Hyun-Shik; Park, Young-Tae; Kabra, Akhil N; Oh, In-Hwan; Choi, Jaeyoung

    2015-08-15

    The biomass and lipid/carbohydrate production by a green microalga Scenedesmus obliquus under mixotrophic condition using food wastewater and flue gas CO2 with municipal wastewater was investigated. Different dilution ratios (0.5-2%) of municipal wastewater with food wastewater were evaluated in the presence of 5, 10 and 14.1% CO2. The food wastewater (0.5-1%) with 10-14.1% CO2 supported the highest growth (0.42-0.44 g L(-1)), nutrient removal (21-22 mg TN L(-1)), lipid productivity (10-11 mg L(-1)day(-1)) and carbohydrate productivity (13-16 mg L(-1)day(-1)) by S. obliquus after 6 days of cultivation. Food wastewater increased the palmitic and oleic acid contents up to 8 and 6%, respectively. Thus, application of food wastewater and flue gas CO2 can be employed for enhancement of growth, lipid/carbohydrate productivity and wastewater treatment efficiency of S. obliquus under mixotrophic condition, which can lead to development of a cost effective strategy for microalgal biomass production.

  12. Utilization of agricultural residues of pineapple peels and sugarcane bagasse as cost-saving raw materials in Scenedesmus acutus for lipid accumulation and biodiesel production.

    PubMed

    Rattanapoltee, Panida; Kaewkannetra, Pakawadee

    2014-07-01

    The aim of this study is to optimize the lipid accumulation in microalgae by using two agricultural residues of pineapple peels and sugarcane bagasse as low-cost organic carbon sources. Green microalgae Scenedesmus acutus was isolated and selected for cultivation. Effects of three initial sugar concentrations and the stage for adding sugar during cultivation on biomass and lipid production were investigated. The results clearly showed that two-stage cultivation is more suitable than one-stage. The maximum biomass concentration and productivity were obtained at 3.85 g/L and 160.42 mg/L/day when sugarcane bagasse was used. The highest lipid content and lipid yield was reached at 28.05 % and 0.93 g/L when pineapple peels were used, while in the case of sugarcane bagasse, 40.89 % and 1.24 g/L lipid content and yield were obtained. Lipid content was found in normal condition (autotrophic) at 17.71 % which was approximately 2.13-fold lower than when sugarcane bagasse was used (40.89 %). Biodiesel production via in situ transesterification was also investigated; the main fatty acids of palmitic acid and oleic acid were found. This work indicates that using agricultural residues as organic carbon sources could be able to increase lipid content and reduce the cost of biofuel production.

  13. Auxin and cytoskeletal organization in algae.

    PubMed

    Jin, Qiaojun; Scherp, Peter; Heimann, Kirsten; Hasenstein, Karl H

    2008-05-01

    Hormones affect growth and alter the cytoskeleton suggesting that hormones and the cytoskeleton interact with each other. The cytoskeleton of ancestral algae such as Chara showed similar sensitivity to auxin as higher plants, even in generative structures but the sensitivity differed between IAA and alpha-NAA and presumably other auxins. The ability of cells to elongate depends on microtubule organization during the transition from disorganized to perpendicular to longitudinal organization of the cytoskeleton. Because of the many functions of the cytoskeleton it is possible that its composition is influenced by selective gene expression and adaptation to growth regulators. Co-localization of microtubules and F-actin change at a high temporal and spatial scale. High resolution measurements of mRNA expression indicate rapid turnover that may affect the composition of the cytoskeleton.

  14. 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.

  15. Autophagy in the model alga Chlamydomonas reinhardtii.

    PubMed

    Pérez-Pérez, María Esther; Crespo, José L

    2010-05-01

    Degradation and recycling of intracellular components via autophagy is conserved among eukaryotes. This catabolic process is mediated by autophagy-related (ATG) proteins, which have been identified in different systems including yeasts, mammals and plants. The genome of the model alga Chlamydomonas reinhardtii contains homologues to yeast and plant ATG genes although autophagy has not been previously described in this organism. In our study, we report the molecular characterization of autophagy in Chlamydomonas. Using the ATG8 protein from Chlamydomonas as a molecular autophagy marker, we demonstrate that this degradative process is induced in stationary cells or under different stresses such as nutrient limitation, oxidative stress or the accumulation of misfolded proteins in the endoplasmic reticulum. Our results also indicate that TOR, a major regulator of autophagy, inhibits this process in Chlamydomonas.

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. Granular activated algae for wastewater treatment.

    PubMed

    Tiron, O; Bumbac, C; Patroescu, I V; Badescu, V R; Postolache, C

    2015-01-01

    The study used activated algae granules for low-strength wastewater treatment in sequential batch mode. Each treatment cycle was conducted within 24 h in a bioreactor exposed to 235 μmol/m²/s light intensity. Wastewater treatment was performed mostly in aerobic conditions, oxygen being provided by microalgae. High removal efficiency of chemical oxygen demand (COD) was achieved (86-98%) in the first hours of the reaction phase, during which the indicator's removal rate was 17.4 ± 3.9 mg O₂/g h; NH(4)(+) was removed during organic matter degradation processes with a rate of 1.8 ± 0.6 mg/g h. After almost complete COD removal, the (O⁺) remaining in the liquor was removed through nitrification processes promoted by the increase of the liquor's oxygen saturation (O₂%), the transformation rate of NH4(+) into NO(3)(-) increasing from 0.14 ± 0.05 to 1.5 ± 0.4 mg NH4(+)/g h, along with an O₂% increase. A wide removal efficiency was achieved in the case of PO(4)(3)(-) (11-85%), with the indicator's removal rate being 1.3 ± 0.7 mg/g h. In the provided optimum conditions, the occurrence of the denitrifying activity was also noticed. A large pH variation was registered (5-8.5) during treatment cycles. The granular activated algae system proved to be a promising alternative for wastewater treatment as it also sustains cost-efficient microalgae harvesting, with microalgae recovery efficiency ranging between 99.85 and 99.99% after granules settling with a velocity of 19 ± 3.6 m/h.

  2. The origin of red algae and the evolution of chloroplasts.

    PubMed

    Moreira, D; Le Guyader, H; Philippe, H

    2000-05-01

    Chloroplast structure and genome analyses support the hypothesis that three groups of organisms originated from the primary photosynthetic endosymbiosis between a cyanobacterium and a eukaryotic host: green plants (green algae + land plants), red algae and glaucophytes (for example, Cyanophora). Although phylogenies based on several mitochondrial genes support a specific green plants/red algae relationship, the phylogenetic analysis of nucleus-encoded genes yields inconclusive, sometimes contradictory results. To address this problem, we have analysed an alternative nuclear marker, elongation factor 2, and included new red algae and protist sequences. Here we provide significant support for a sisterhood of green plants and red algae. This sisterhood is also significantly supported by a multi-gene analysis of a fusion of 13 nuclear markers (5,171 amino acids). In addition, the analysis of an alternative fusion of 6 nuclear markers (1,938 amino acids) indicates that glaucophytes may be the closest relatives to the green plants/red algae group. Thus, our study provides evidence from nuclear markers for a single primary endosymbiosis at the origin of these groups, and supports a kingdom Plantae comprising green plants, red algae and glaucophytes.

  3. 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.

  4. Algae biomass cultivation in nitrogen rich biogas digestate.

    PubMed

    Krustok, I; Diaz, J G; Odlare, M; Nehrenheim, E

    2015-01-01

    Because microalgae are known for quick biomass growth and nutrient uptake, there has been much interest in their use in research on wastewater treatment methods. While many studies have concentrated on the algal treatment of wastewaters with low to medium ammonium concentrations, there are several liquid waste streams with high ammonium concentrations that microalgae could potentially treat. The aim of this paper was to test ammonium tolerance of the indigenous algae community of Lake Mälaren and to use this mixed consortia of algae to remove nutrients from biogas digestate. Algae from Lake Mälaren were cultivated in Jaworski's Medium containing a range of ammonium concentrations and the resulting algal growth was determined. The algae were able to grow at NH4-N concentrations of up to 200 mg L(-1) after which there was significant inhibition. To test the effectiveness of the lake water algae on the treatment of biogas digestate, different pre-cultivation set-ups and biogas digestate concentrations were tested. It was determined that mixing pre-cultivated suspension algae with 25% of biogas digestate by volume, resulting in an ammonium concentration of around 300 mg L(-1), produced the highest algal growth. The algae were effective in removing 72.8±2.2% of NH4-N and 41.4±41.4% of PO4-P. PMID:26540532

  5. Biomass of algae growth on natural water medium.

    PubMed

    Ramaraj, Rameshprabu; Tsai, David Dah-Wei; Chen, Paris Honglay

    2015-01-01

    Algae are the dominant primary producers in aquatic ecosystems. Since algae are highly varied group organisms, which have important functions in ecosystem, and their biomass is an essential biological resource. Currently, algae have been applied increasingly to diverse range of biomass applications. Therefore, this study was aimed to investigate the ecological algae features of microalgal production by natural medium, ecological function by lab scale of the symbiotic reactor which is imitated nature ecosystem, and atmospheric CO2 absorption that was related the algal growth of biomass to understand algae in natural water body better. Consequently, this study took advantages of using the unsupplemented freshwater natural medium to produce microalgae. Algal biomass by direct measurement of total suspended solids (TSS) and volatile suspended solids (VSS) resulted as 0.14g/L and 0.08g/L respectively. The biomass measurements of TSS and VSS are the sensible biomass index for algae production. The laboratory results obtained in the present study proved the production of algae by the natural water medium is potentially feasible.

  6. Algae biomass cultivation in nitrogen rich biogas digestate.

    PubMed

    Krustok, I; Diaz, J G; Odlare, M; Nehrenheim, E

    2015-01-01

    Because microalgae are known for quick biomass growth and nutrient uptake, there has been much interest in their use in research on wastewater treatment methods. While many studies have concentrated on the algal treatment of wastewaters with low to medium ammonium concentrations, there are several liquid waste streams with high ammonium concentrations that microalgae could potentially treat. The aim of this paper was to test ammonium tolerance of the indigenous algae community of Lake Mälaren and to use this mixed consortia of algae to remove nutrients from biogas digestate. Algae from Lake Mälaren were cultivated in Jaworski's Medium containing a range of ammonium concentrations and the resulting algal growth was determined. The algae were able to grow at NH4-N concentrations of up to 200 mg L(-1) after which there was significant inhibition. To test the effectiveness of the lake water algae on the treatment of biogas digestate, different pre-cultivation set-ups and biogas digestate concentrations were tested. It was determined that mixing pre-cultivated suspension algae with 25% of biogas digestate by volume, resulting in an ammonium concentration of around 300 mg L(-1), produced the highest algal growth. The algae were effective in removing 72.8±2.2% of NH4-N and 41.4±41.4% of PO4-P.

  7. [Seasonal variation characteristics of algae biomass in Chaohu Lake].

    PubMed

    Jiang, Xia; Wang, Shu-Hang; Zhong, Li-Xiang; Jin, Xiang-Can; Sun, Shi-Qun

    2010-09-01

    The biomass and distribution of algae community in Chaohu Lake were investigated in 2008. At the same time, the seasonal variations of algae translocation between the sediment and overlying water were also quantitative studied by self-made "algae up/down trap". Chaohu Lake was dominated by Cyanobacteria all the year, and dominant Cyanobacteria species changed in different seasons. In spring, Anabaena was the dominant species, and Microcystis was the subdominant species; In the whole summer and autumn, the dominant species is Microcystis. Algae biomass increased significantly from May and the maximum appeared in August, was 146.37 mg x m(-3) with Chl-a. The value of algae biomass were 9.75-16.24 mg x kg(-1) in the surface sediments, and the minimum appeared in Summer, then the algae biomass increased gradually with the maximum value in winter. Translocation process between the sediment and the overlying water occurred throughout the study period. The recruitment rates increased at first with the maximum rates in early August, was 0.036 8 mg x (m2 x d) (-1), and then had a downward tendency. However the sedimentation rates increased slowly firstly with the maximum rate in early September, then it decreased sharply, was 0.032 1 mg x (m2 x d)(-1). Multiple stepwise regression showed that temperature was the most significant factor for the algae biomass in Chaohu Lake, Total nitrogen (TN) and Total phosphorus(TP) are sub-important factors.

  8. 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.

  9. 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.

  10. Photobiological hydrogen production with switchable photosystem-II designer algae

    DOEpatents

    Lee, James Weifu

    2014-02-18

    A process for enhanced photobiological H.sub.2 production using transgenic alga. The process includes inducing exogenous genes in a transgenic alga by manipulating selected environmental factors. In one embodiment inducing production of an exogenous gene uncouples H.sub.2 production from existing mechanisms that would downregulate H.sub.2 production in the absence of the exogenous gene. In other embodiments inducing an exogenous gene triggers a cascade of metabolic changes that increase H.sub.2 production. In some embodiments the transgenic alga are rendered non-regenerative by inducing exogenous transgenes for proton channel polypeptides that are targeted to specific algal membranes.

  11. Occurrence of non-hydrolysable amides in the macromolecular constituent of Scenedesmus quadricauda cell wall as revealed by [sup 15]N NMR: Origin of n-alkylnitriles in pyrolysates of ultralaminai-containing kerogens

    SciTech Connect

    Derenne, S.; Largeau, C. ); Taulelle, F. )

    1993-02-01

    New structures, termed ultralaminae, were recently shown to occur in kerogens from numerous oil shales and source rocks. Morphological and chemical studies revealed that ultralaminae originate from the selective preservation of the non-hydrolysable biomacromolecules (algaenans) building up the thin outer walls of several Chlorophyceae (green microalgae) including the cosmopolitan general Scenedesmus and Chlorella. The chemical correlation between such algaenans and fossil ultralaminae was mainly based on the production, on pyrolysis, of nitrogen compounds, n-alkylnitriles, with specific distributions depending on the lacustrine of marine origin of the considered samples. In addition, these bio-and geopolymers were characterized by quite high N levels.

  12. Application of synthetic biology in cyanobacteria and algae

    PubMed Central

    Wang, Bo; Wang, Jiangxin; Zhang, Weiwen; Meldrum, Deirdre R.

    2012-01-01

    Cyanobacteria and algae are becoming increasingly attractive cell factories for producing renewable biofuels and chemicals due to their ability to capture solar energy and CO2 and their relatively simple genetic background for genetic manipulation. Increasing research efforts from the synthetic biology approach have been made in recent years to modify cyanobacteria and algae for various biotechnological applications. In this article, we critically review recent progresses in developing genetic tools for characterizing or manipulating cyanobacteria and algae, the applications of genetically modified strains for synthesizing renewable products such as biofuels and chemicals. In addition, the emergent challenges in the development and application of synthetic biology for cyanobacteria and algae are also discussed. PMID:23049529

  13. Evaluation of filamentous green algae as feedstocks for biofuel production.

    PubMed

    Zhang, Wei; Zhao, Yonggang; Cui, Binjie; Wang, Hui; Liu, Tianzhong

    2016-11-01

    Compared with unicellular microalgae, filamentous algae have high resistance to grazer-predation and low-cost recovery in large-scale production. Green algae, as the most diverse group of algae, included numerous filamentous genera and species. In this study, records of filamentous genera and species in green algae were firstly censused and classified. Then, seven filamentous strains subordinated in different genera were cultivated in bubbled-column to investigate their growth rate and energy molecular (lipid and starch) capacity. Four strains including Stigeoclonium sp., Oedogonium nodulosum, Hormidium sp. and Zygnema extenue were screened out due to their robust growth. And they all could accumulate triacylglycerols and starch in their biomass, but with different capacity. After nitrogen starvation, Hormidium sp. and Oedogonium nodulosum respectively exhibited high capacity of lipid (45.38% in dry weight) and starch (46.19% in dry weight) accumulation, which could be of high potential as feedstocks for biodiesel and bioethanol production. PMID:27598569

  14. Colourful Cultures: Classroom Experiments with the Unicellular Alga Haematococcus pluvialis.

    ERIC Educational Resources Information Center

    Delpech, Roger

    2001-01-01

    Describes an investigation into the photosynthetic potential of the different developmental stages of the green unicellular alga Haematococcus pluvialis. Reviews the biotechnological applications of astaxanthin, the red pigment which can be extracted from Haematococcus pluvialis. (Author/MM)

  15. Bicarbonate produced from carbon capture for algae culture.

    PubMed

    Chi, Zhanyou; O'Fallon, James V; Chen, Shulin

    2011-11-01

    Using captured CO(2) to grow microalgae is limited by the high cost of CO(2) capture and transportation, as well as significant CO(2) loss during algae culture. Moreover, algae grow poorly at night, but CO(2) cannot be temporarily stored until sunrise. To address these challenges, we discuss a process where CO(2) is captured as bicarbonate and used as feedstock for algae culture, and the carbonate regenerated by the culture process is used as an absorbent to capture more CO(2). This process would significantly reduce carbon capture costs because it does not require additional energy for carbonate regeneration. Furthermore, not only would transport of the aqueous bicarbonate solution cost less than for that of compressed CO(2), but using bicarbonate would also provide a superior alternative for CO(2) delivery to an algae culture system.

  16. CONTROL TECHNOLOGY EXTRACTION OF MERCURY FROM GROUNDWATER IMMOBILIZED ALGAE

    EPA Science Inventory

    Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contamina...

  17. Harmful algae blooms removal from fresh water with modified vermiculite.

    PubMed

    Miao, Chunguang; Tang, Yi; Zhang, Hong; Wu, Zhengyan; Wang, Xiangqin

    2014-01-01

    Vermiculite and vermiculite modified with hydrochloric acid were investigated to evaluate their flocculation efficiencies in freshwater containing harmful algae blooms (HABs) (Microcystis aeruginosa). Scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, converted fluorescence microscope, plasma-atomic emission spectrometry, and Zetasizer were used to study the flocculation mechanism of modified vermiculite. It was found that the vermiculite modified with hydrochloric acid could coagulate algae cells through charge neutralization, chemical bridging, and netting effect. The experimental results show that the efficiency of flocculation can be notably improved by modified vermiculite. Ninety-eight per cent of algae cells in algae solution could be removed within 10 min after the addition ofmodified vermiculite clay. The method that removal of HABs with modified vermiculite is economical with high efficiency, and more research is needed to assess their ecological impacts before using in practical application.

  18. Evaluation of filamentous green algae as feedstocks for biofuel production.

    PubMed

    Zhang, Wei; Zhao, Yonggang; Cui, Binjie; Wang, Hui; Liu, Tianzhong

    2016-11-01

    Compared with unicellular microalgae, filamentous algae have high resistance to grazer-predation and low-cost recovery in large-scale production. Green algae, as the most diverse group of algae, included numerous filamentous genera and species. In this study, records of filamentous genera and species in green algae were firstly censused and classified. Then, seven filamentous strains subordinated in different genera were cultivated in bubbled-column to investigate their growth rate and energy molecular (lipid and starch) capacity. Four strains including Stigeoclonium sp., Oedogonium nodulosum, Hormidium sp. and Zygnema extenue were screened out due to their robust growth. And they all could accumulate triacylglycerols and starch in their biomass, but with different capacity. After nitrogen starvation, Hormidium sp. and Oedogonium nodulosum respectively exhibited high capacity of lipid (45.38% in dry weight) and starch (46.19% in dry weight) accumulation, which could be of high potential as feedstocks for biodiesel and bioethanol production.

  19. Photobiological hydrogen production in green algae and photosynthetic bacteria

    SciTech Connect

    Greenbaum, E.

    1986-01-01

    We have shown that, under appropriate physiological conditions, certain freshwater and marine green algae are capable of splitting water to molecular hydrogen and oxygen in a sustained steady-state reaction. In these algae, the gaseous-fuel-producing reaction can be driven by light throughout the visible portion of the solar emission spectrum, including the long wavelength (red) 700-nm region. No external energy sources are required.

  20. Algae Reefs in Shark Bay, Western Australia, Australia

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Numerous algae reefs are seen in Shark Bay, Western Australia, Australia (26.0S, 113.5E) especially in the southern portions of the bay. The south end is more saline because tidal flow in and out of the bay is restricted by sediment deposited at the north and central end of the bay opposite the mouth of the Wooramel River. This extremely arid region produces little sediment runoff so that the waters are very clear, saline and rich in algae.

  1. An overview of algae biofuel production and potential environmental impact.

    PubMed

    Menetrez, Marc Y

    2012-07-01

    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) and produce products with a wide variety of compositions and uses. These products include lipids, which can be processed into biodiesel; carbohydrates, which can be processed into ethanol; and proteins, which can be used for human and animal consumption. Algae are commonly genetically engineered to allow for advantageous process modification or optimization. However, issues remain regarding human exposure to algae-derived toxins, allergens, and carcinogens from both existing and genetically modified organisms (GMOs), as well as the overall environmental impact of GMOs. A literature review was performed to highlight issues related to the growth and use of algal products for generating biofuels. Human exposure and environmental impact issues are identified and discussed, as well as current research and development activities of academic, commercial, and governmental groups. It is hoped that the ideas contained in this paper will increase environmental awareness of issues surrounding the production of algae and will help the algae industry develop to its full potential. PMID:22681590

  2. Development of Green Fuels From Algae - The University of Tulsa

    SciTech Connect

    Crunkleton, Daniel; Price, Geoffrey; Johannes, Tyler; Cremaschi, Selen

    2012-12-03

    The general public has become increasingly aware of the pitfalls encountered with the continued reliance on fossil fuels in the industrialized world. In response, the scientific community is in the process of developing non-fossil fuel technologies that can supply adequate energy while also being environmentally friendly. In this project, we concentrate on green fuels which we define as those capable of being produced from renewable and sustainable resources in a way that is compatible with the current transportation fuel infrastructure. One route to green fuels that has received relatively little attention begins with algae as a feedstock. Algae are a diverse group of aquatic, photosynthetic organisms, generally categorized as either macroalgae (i.e. seaweed) or microalgae. Microalgae constitute a spectacularly diverse group of prokaryotic and eukaryotic unicellular organisms and account for approximately 50% of global organic carbon fixation. The PI's have subdivided the proposed research program into three main research areas, all of which are essential to the development of commercially viable algae fuels compatible with current energy infrastructure. In the fuel development focus, catalytic cracking reactions of algae oils is optimized. In the species development project, genetic engineering is used to create microalgae strains that are capable of high-level hydrocarbon production. For the modeling effort, the construction of multi-scaled models of algae production was prioritized, including integrating small-scale hydrodynamic models of algae production and reactor design and large-scale design optimization models.

  3. Extraction of mercury from ground-water using immobilized algae

    SciTech Connect

    Barkley, N.P.

    1991-01-01

    Bio-recovery Systems Inc., conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to absorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algae biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into absorption columns, exhibited excellent flow characteristics, and functioned as a 'biological' ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of the product to absorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded non-repeatable results with samples collected at different times of the year. The strategy of extracting the groundwater through two columns containing different times of the year. The strategy of extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity. (Copyright (c) 1991--Air and Waste Management Association.)

  4. Study on algae removal by immobilized biosystem on sponge

    NASA Astrophysics Data System (ADS)

    Pei, Haiyan; Hu, Wenrong

    2006-10-01

    In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake’s water after 7 d of domestication. The removal efficiency for algae, organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5h, the removal rates of algae, microcystins and UV260 were 90%, 94.17% and 84%, respectively. The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans. Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

  5. An overview of algae biofuel production and potential environmental impact.

    PubMed

    Menetrez, Marc Y

    2012-07-01

    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) and produce products with a wide variety of compositions and uses. These products include lipids, which can be processed into biodiesel; carbohydrates, which can be processed into ethanol; and proteins, which can be used for human and animal consumption. Algae are commonly genetically engineered to allow for advantageous process modification or optimization. However, issues remain regarding human exposure to algae-derived toxins, allergens, and carcinogens from both existing and genetically modified organisms (GMOs), as well as the overall environmental impact of GMOs. A literature review was performed to highlight issues related to the growth and use of algal products for generating biofuels. Human exposure and environmental impact issues are identified and discussed, as well as current research and development activities of academic, commercial, and governmental groups. It is hoped that the ideas contained in this paper will increase environmental awareness of issues surrounding the production of algae and will help the algae industry develop to its full potential.

  6. Radionuclides and trace metals in eastern Mediterranean Sea algae.

    PubMed

    Al-Masri, M S; Mamish, S; Budier, Y

    2003-01-01

    Three types of sea alga distributed along the Syrian coast have been collected and analyzed for radioactivity and trace elements. Results have shown that (137)Cs concentrations in all the analyzed sample were relatively low (less than 1.2 Bq kg(-1) dry weight) while the levels of naturally occurring radionuclides, such as (210)Po and (210)Pb, were found to be high in most samples; the highest observed value (27.43 Bq kg(-1) dry weight) for (210)Po being in the red Jania longifurca alga. In addition, most brown alga species were also found to accumulate (210)Po, which indicates their selectivity to this isotope. On the other hand, brown alga (Cystoseira and Sargassum Vulgare) have shown a clear selectivity for some trace metals such as Cr, As, Cu and Co, this selectivity may encourage their use as biomonitor for pollution by trace metals. Moreover, the red alga species were found to contain the highest levels of Mg while the brown alga species were found to concentrate Fe, Mn, Na and K and nonmetals such as Cl, I and Br. PMID:12660047

  7. Feeding preferences of mesograzers on aquacultured Gracilaria and sympatric algae

    PubMed Central

    Cruz-Rivera, Edwin; Friedlander, Michael

    2011-01-01

    While large grazers can often be excluded effectively from algal aquaculture operations, smaller herbivores such as small crustaceans and gastropods may be more difficult to control. The susceptibility of three Gracilaria species to herbivores was evaluated in multiple-choice experiments with the amphipod Ampithoe ramondi and the crab Acanthonyx lunulatus. Both mesograzers are common along the Mediterranean coast of Israel. When given a choice, the amphipod preferred to consume Gracilaria lemaneiformis significantly more than either G. conferta or G. cornea. The crab, however, consumed equivalent amounts of G. lemaneiformis and G. conferta, but did not consume G. cornea. Organic content of these algae, an important feeding cue for some mesograzers, could not account for these differences. We further assessed the susceptibility of a candidate species for aquaculture, G. lemaneiformis, against local algae, including common epiphytes. When given a choice of four algae, amphipods preferred the green alga Ulva lactuca over Jania rubens. However, consumption of U. lactuca was equivalent to those of G. lemaneiformis and Padina pavonica. In contrast, the crab showed a marked and significant preference for G. lemaneiformis above any of the other three algae offered. Our results suggest that G. cornea is more resistant to herbivory from common mesograzers and that, contrary to expectations, mixed cultures or epiphyte growth on G. lemaneiformis cannot reduce damage to this commercially appealing alga if small herbivores are capable of recruiting into culture ponds. Mixed cultures may be beneficial when culturing other Gracilaria species. PMID:22711945

  8. Comparative Transcriptome Analysis of Four Prymnesiophyte Algae

    PubMed Central

    Koid, Amy E.; Liu, Zhenfeng; Terrado, Ramon; Jones, Adriane C.; Caron, David A.; Heidelberg, Karla B.

    2014-01-01

    Genomic studies of bacteria, archaea and viruses have provided insights into the microbial world by unveiling potential functional capabilities and molecular pathways. However, the rate of discovery has been slower among microbial eukaryotes, whose genomes are larger and more complex. Transcriptomic approaches provide a cost-effective alternative for examining genetic potential and physiological responses of microbial eukaryotes to environmental stimuli. In this study, we generated and compared the transcriptomes of four globally-distributed, bloom-forming prymnesiophyte algae: Prymnesium parvum, Chrysochromulina brevifilum, Chrysochromulina ericina and Phaeocystis antarctica. Our results revealed that the four transcriptomes possess a set of core genes that are similar in number and shared across all four organisms. The functional classifications of these core genes using the euKaryotic Orthologous Genes (KOG) database were also similar among the four study organisms. More broadly, when the frequencies of different cellular and physiological functions were compared with other protists, the species clustered by both phylogeny and nutritional modes. Thus, these clustering patterns provide insight into genomic factors relating to both evolutionary relationships as well as trophic ecology. This paper provides a novel comparative analysis of the transcriptomes of ecologically important and closely related prymnesiophyte protists and advances an emerging field of study that uses transcriptomics to reveal ecology and function in protists. PMID:24926657

  9. Microfluidic one-way streets for algae

    NASA Astrophysics Data System (ADS)

    Dunkel, Jorn; Kantsler, Vasily; Polin, Marco; Goldstein, Raymond E.

    2012-02-01

    Controlling locomotion and transport of microorganisms is a key challenge in the development of future biotechnological applications. Here, we demonstrate the use of optimized microfluidic ratchets to rectify the mean swimming direction in suspensions of the unicellular green alga Chlamydomonas reinhardtii, which is a promising candidate for the photosynthetic production of hydrogen. To assess the potential of microfluidic barriers for the manipulation of algal swimming, we studied first the scattering of individual C. reinhardtii from solid boundaries. High-speed imaging reveals the surprising result that these quasi-spherical ``puller''-type microswimmers primarily interact with surfaces via direct flagellar contact, whereas hydrodynamic effects play a subordinate role. A minimal theoretical model, based on run-and-turn motion and the experimentally measured surface-scattering law, predicts the existence of optimal wedge-shaped ratchets that maximize rectification of initially uniform suspensions. We confirm this prediction in experimental measurements with different geometries. Since the mechano-elastic properties of eukaryotic flagella are conserved across many genera, we expect that our results and methods are applicable to a broad class of biflagellate microorganisms.

  10. Mixotrophy in red tide algae raphidophytes.

    PubMed

    Jeong, Hae Jin

    2011-01-01

    Marine raphidophytes are common red tide organisms that are distributed worldwide. They are known to be harmful to other plankton and fish and have often caused large-scale fish mortality in many countries. Thus, the population dynamics of raphidophytes is a critical concern for scientists, the aquaculture industry, and government officers from many countries. Raphidophyte growth and mortality should be investigated to understand bloom dynamics. Raphidophytes were thought to be exclusively autotrophic organisms. However, several recent studies have revealed that raphidophytes are able to feed on heterotrophic and autotrophic bacteria, i.e. raphidophytes are mixotrophic algae. Further, high-resolution video microscopy has revealed the mechanism by which raphidophytes feed on bacteria, which involves capturing prey cells in the mucus excreted by mucocysts and engulfing the cells through mucocysts. These discoveries may influence the conventional view on both raphidophyte bloom dynamics and plankton energy flow and carbon cycling. In the present study, I review prey, feeding mechanisms, and ingestion rates of mixotrophic marine raphidophytes. In addition, I examine the ecological significance of raphidophyte mixotrophy.

  11. Comparative transcriptome analysis of four prymnesiophyte algae.

    PubMed

    Koid, Amy E; Liu, Zhenfeng; Terrado, Ramon; Jones, Adriane C; Caron, David A; Heidelberg, Karla B

    2014-01-01

    Genomic studies of bacteria, archaea and viruses have provided insights into the microbial world by unveiling potential functional capabilities and molecular pathways. However, the rate of discovery has been slower among microbial eukaryotes, whose genomes are larger and more complex. Transcriptomic approaches provide a cost-effective alternative for examining genetic potential and physiological responses of microbial eukaryotes to environmental stimuli. In this study, we generated and compared the transcriptomes of four globally-distributed, bloom-forming prymnesiophyte algae: Prymnesium parvum, Chrysochromulina brevifilum, Chrysochromulina ericina and Phaeocystis antarctica. Our results revealed that the four transcriptomes possess a set of core genes that are similar in number and shared across all four organisms. The functional classifications of these core genes using the euKaryotic Orthologous Genes (KOG) database were also similar among the four study organisms. More broadly, when the frequencies of different cellular and physiological functions were compared with other protists, the species clustered by both phylogeny and nutritional modes. Thus, these clustering patterns provide insight into genomic factors relating to both evolutionary relationships as well as trophic ecology. This paper provides a novel comparative analysis of the transcriptomes of ecologically important and closely related prymnesiophyte protists and advances an emerging field of study that uses transcriptomics to reveal ecology and function in protists.

  12. Is the Future Really in Algae?

    NASA Technical Reports Server (NTRS)

    Trent, Jonathan

    2011-01-01

    Having just emerged from the warmest decade on record and watching as the oceans acidify, global resources peak, the world's population continues to climb, and nearly half of all known species face extinction by the end of the century. We stand on the threshold of one of the most important transition in human history-the transition from hunting-and-gathering our energy to cultivating sustainable, carbon-neutral, environmentally-friendly energy supplies. Can we "cultivate" enerm without competing with agriculture for land, freshwater, or fertilizer? Can we develop an "ecology of technology" that optimizes our use of limited resources? Is human activity compatible with improved conditions in the world's oceans? Will our ingenuity prevail in time to make a difference for our children and the children of all species? With support from NASA ARMD and the California Energy Commission, a group of dedicated scientists and engineers are working on a project called OMEGA (Offshore Membrane Enclosures for Growing Algae), to provide practical answers to these critical questions and to leave a legacy of hope for the oceans and for the future.

  13. An integrated microalgal growth model and its application to optimize the biomass production of Scenedesmus sp. LX1 in open pond under the nutrient level of domestic secondary effluent.

    PubMed

    Wu, Yin-Hu; Li, Xin; Yu, Yin; Hu, Hong-Ying; Zhang, Tian-Yuan; Li, Feng-Min

    2013-09-01

    Microalgal growth is the key to the coupled system of wastewater treatment and microalgal biomass production. In this study, Monod model, Droop model and Steele model were incorporated to obtain an integrated growth model describing the combined effects of nitrogen, phosphorus and light intensity on the growth rate of Scenedesmus sp. LX1. The model parameters were obtained via fitting experimental data to these classical models. Furthermore, the biomass production of Scenedesmus sp. LX1 in open pond under nutrient level of secondary effluent was analyzed based on the integrated model, predicting a maximal microalgal biomass production rate about 20 g m(-2) d(-1). In order to optimize the biomass production of open pond the microalgal biomass concentration, light intensity on the surface of open pond, total depth of culture medium and hydraulic retention time should be 500 g m(-3), 16,000 lx, 0.2 m and 5.2 d in the conditions of this study, respectively. PMID:23891148

  14. Two-step evolution of endosymbiosis between hydra and algae.

    PubMed

    Ishikawa, Masakazu; Shimizu, Hiroshi; Nozawa, Masafumi; Ikeo, Kazuho; Gojobori, Takashi

    2016-10-01

    In the Hydra vulgaris group, only 2 of the 25 strains in the collection of the National Institute of Genetics in Japan currently show endosymbiosis with green algae. However, whether the other non-symbiotic strains also have the potential to harbor algae remains unknown. The endosymbiotic potential of non-symbiotic strains that can harbor algae may have been acquired before or during divergence of the strains. With the aim of understanding the evolutionary process of endosymbiosis in the H. vulgaris group, we examined the endosymbiotic potential of non-symbiotic strains of the H. vulgaris group by artificially introducing endosymbiotic algae. We found that 12 of the 23 non-symbiotic strains were able to harbor the algae until reaching the grand-offspring through the asexual reproduction by budding. Moreover, a phylogenetic analysis of mitochondrial genome sequences showed that all the strains with endosymbiotic potential grouped into a single cluster (cluster γ). This cluster contained two strains (J7 and J10) that currently harbor algae; however, these strains were not the closest relatives. These results suggest that evolution of endosymbiosis occurred in two steps; first, endosymbiotic potential was gained once in the ancestor of the cluster γ lineage; second, strains J7 and J10 obtained algae independently after the divergence of the strains. By demonstrating the evolution of the endosymbiotic potential in non-symbiotic H. vulgaris group strains, we have clearly distinguished two evolutionary steps. The step-by-step evolutionary process provides significant insight into the evolution of endosymbiosis in cnidarians. PMID:27404042

  15. Two-step evolution of endosymbiosis between hydra and algae.

    PubMed

    Ishikawa, Masakazu; Shimizu, Hiroshi; Nozawa, Masafumi; Ikeo, Kazuho; Gojobori, Takashi

    2016-10-01

    In the Hydra vulgaris group, only 2 of the 25 strains in the collection of the National Institute of Genetics in Japan currently show endosymbiosis with green algae. However, whether the other non-symbiotic strains also have the potential to harbor algae remains unknown. The endosymbiotic potential of non-symbiotic strains that can harbor algae may have been acquired before or during divergence of the strains. With the aim of understanding the evolutionary process of endosymbiosis in the H. vulgaris group, we examined the endosymbiotic potential of non-symbiotic strains of the H. vulgaris group by artificially introducing endosymbiotic algae. We found that 12 of the 23 non-symbiotic strains were able to harbor the algae until reaching the grand-offspring through the asexual reproduction by budding. Moreover, a phylogenetic analysis of mitochondrial genome sequences showed that all the strains with endosymbiotic potential grouped into a single cluster (cluster γ). This cluster contained two strains (J7 and J10) that currently harbor algae; however, these strains were not the closest relatives. These results suggest that evolution of endosymbiosis occurred in two steps; first, endosymbiotic potential was gained once in the ancestor of the cluster γ lineage; second, strains J7 and J10 obtained algae independently after the divergence of the strains. By demonstrating the evolution of the endosymbiotic potential in non-symbiotic H. vulgaris group strains, we have clearly distinguished two evolutionary steps. The step-by-step evolutionary process provides significant insight into the evolution of endosymbiosis in cnidarians.

  16. Plasticity predicts evolution in a marine alga.

    PubMed

    Schaum, C Elisa; Collins, Sinéad

    2014-10-22

    Under global change, populations have four possible responses: 'migrate, acclimate, adapt or die' (Gienapp et al. 2008 Climate change and evolution: disentangling environmental and genetic response. Mol. Ecol. 17, 167-178. (doi:10.1111/j.1365-294X.2007.03413.x)). The challenge is to predict how much migration, acclimatization or adaptation populations are capable of. We have previously shown that populations from more variable environments are more plastic (Schaum et al. 2013 Variation in plastic responses of a globally distributed picoplankton species to ocean acidification. Nature 3, 298-230. (doi:10.1038/nclimate1774)), and here we use experimental evolution with a marine microbe to learn that plastic responses predict the extent of adaptation in the face of elevated partial pressure of CO2 (pCO2). Specifically, plastic populations evolve more, and plastic responses in traits other than growth can predict changes in growth in a marine microbe. The relationship between plasticity and evolution is strongest when populations evolve in fluctuating environments, which favour the evolution and maintenance of plasticity. Strikingly, plasticity predicts the extent, but not direction of phenotypic evolution. The plastic response to elevated pCO2 in green algae is to increase cell division rates, but the evolutionary response here is to decrease cell division rates over 400 generations until cells are dividing at the same rate their ancestors did in ambient CO2. Slow-growing cells have higher mitochondrial potential and withstand further environmental change better than faster growing cells. Based on this, we hypothesize that slow growth is adaptive under CO2 enrichment when associated with the production of higher quality daughter cells.

  17. Electrophysiology of turgor regulation in marine siphonous green algae.

    PubMed

    Bisson, M A; Beilby, M J; Shepherd, V A

    2006-05-01

    We review electrophysiological measures of turgor regulation in some siphonous green algae, primarily the giant-celled marine algae, Valonia and Ventricaria, with particular comparison to the well studied charophyte algae Chara and Lamprothamnium. The siphonous green algae have a less negative plasma membrane potential, and are unlikely to have a proton-based chemiosmotic transport system, dominated by active electrogenic K(+) uptake. We also make note of the unusual cellular structure of the siphonous green algae. Hypertonic stress, due to increased external osmotic pressure, is accompanied by positive-going potential difference (PD), increase in conductance, and slow turgor regulation. The relationship between these is not yet resolved, but may involve changes in K(+ )conductance (G (K)) or active K(+) transport at both membranes. Hypotonic turgor regulation, in response to decreased external osmotic pressure, is approximately 3 times faster than hypertonic turgor regulation. It is accompanied by a negative-going PD, although conductance also increases. The conductance increase and the magnitude of the PD change are strongly correlated with the magnitude of hypotonic stress.

  18. Anti-Phytopathogenic Activities of Macro-Algae Extracts

    PubMed Central

    Jiménez, Edra; Dorta, Fernando; Medina, Cristian; Ramírez, Alberto; Ramírez, Ingrid; Peña-Cortés, Hugo

    2011-01-01

    Aqueous and ethanolic extracts obtained from nine Chilean marine macro-algae collected at different seasons were examined in vitro and in vivo for properties that reduce the growth of plant pathogens or decrease the injury severity of plant foliar tissues following pathogen infection. Particular crude aqueous or organic extracts showed effects on the growth of pathogenic bacteria whereas others displayed important effects against pathogenic fungi or viruses, either by inhibiting fungal mycelia growth or by reducing the disease symptoms in leaves caused by pathogen challenge. Organic extracts obtained from the brown-alga Lessonia trabeculata inhibited bacterial growth and reduced both the number and size of the necrotic lesion in tomato leaves following infection with Botrytis cinerea. Aqueous and ethanolic extracts from the red-alga Gracillaria chilensis prevent the growth of Phytophthora cinnamomi, showing a response which depends on doses and collecting-time. Similarly, aqueous and ethanolic extracts from the brown-alga Durvillaea antarctica were able to diminish the damage caused by tobacco mosaic virus (TMV) in tobacco leaves, and the aqueous procedure is, in addition, more effective and seasonally independent. These results suggest that macro-algae contain compounds with different chemical properties which could be considered for controlling specific plant pathogens. PMID:21673886

  19. Boron uptake, localization, and speciation in marine brown algae.

    PubMed

    Miller, Eric P; Wu, Youxian; Carrano, Carl J

    2016-02-01

    In contrast to the generally boron-poor terrestrial environment, the concentration of boron in the marine environment is relatively high (0.4 mM) and while there has been extensive interest in its use as a surrogate of pH in paleoclimate studies in the context of climate change-related questions, the relatively depth independent, and the generally non-nutrient-like concentration profile of this element have led to boron being neglected as a potentially biologically relevant element in the ocean. Among the marine plant-like organisms the brown algae (Phaeophyta) are one of only five lineages of photosynthetic eukaryotes to have evolved complex multicellularity. Many of unusual and often unique features of brown algae are attributable to this singular evolutionary history. These adaptations are a reflection of the marine coastal environment which brown algae dominate in terms of biomass. Consequently, brown algae are of fundamental importance to oceanic ecology, geochemistry, and coastal industry. Our results indicate that boron is taken up by a facilitated diffusion mechanism against a considerable concentration gradient. Furthermore, in both Ectocarpus and Macrocystis some boron is most likely bound to cell wall constituent alginate and the photoassimilate mannitol located in sieve cells. Herein, we describe boron uptake, speciation, localization and possible biological function in two species of brown algae, Macrocystis pyrifera and Ectocarpus siliculosus. PMID:26679972

  20. Visualization of oxygen distribution patterns caused by coral and algae.

    PubMed

    Haas, Andreas F; Gregg, Allison K; Smith, Jennifer E; Abieri, Maria L; Hatay, Mark; Rohwer, Forest

    2013-01-01

    Planar optodes were used to visualize oxygen distribution patterns associated with a coral reef associated green algae (Chaetomorpha sp.) and a hermatypic coral (Favia sp.) separately, as standalone organisms, and placed in close proximity mimicking coral-algal interactions. Oxygen patterns were assessed in light and dark conditions and under varying flow regimes. The images show discrete high oxygen concentration regions above the organisms during lighted periods and low oxygen in the dark. Size and orientation of these areas were dependent on flow regime. For corals and algae in close proximity the 2D optodes show areas of extremely low oxygen concentration at the interaction interfaces under both dark (18.4 ± 7.7 µmol O2 L(- 1)) and daylight (97.9 ± 27.5 µmol O2 L(- 1)) conditions. These images present the first two-dimensional visualization of oxygen gradients generated by benthic reef algae and corals under varying flow conditions and provide a 2D depiction of previously observed hypoxic zones at coral algae interfaces. This approach allows for visualization of locally confined, distinctive alterations of oxygen concentrations facilitated by benthic organisms and provides compelling evidence for hypoxic conditions at coral-algae interaction zones.

  1. Application of algae-biosensor for environmental monitoring.

    PubMed

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

    2015-01-01

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

  2. Extraction of mercury from groundwater using immobilized algae

    SciTech Connect

    Barkley, N.P. )

    1991-10-01

    Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algal biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into adsorption columns, exhibited excellent flow characteristics, and functioned as a biological ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of this product to adsorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded nonrepeatable results with samples collected at different times of the year. The strategy of sequentially extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity.

  3. Algae-bacteria interactions: Evolution, ecology and emerging applications.

    PubMed

    Ramanan, Rishiram; Kim, Byung-Hyuk; Cho, Dae-Hyun; Oh, Hee-Mock; Kim, Hee-Sik

    2016-01-01

    Algae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as varied as deep seas to lichens and represent all conceivable modes of interactions - from mutualism to parasitism. Several studies have shown that algae and bacteria synergistically affect each other's physiology and metabolism, a classic case being algae-roseobacter interaction. These interactions are ubiquitous and define the primary productivity in most ecosystems. In recent years, algae have received much attention for industrial exploitation but their interaction with bacteria is often considered a contamination during commercialization. A few recent studies have shown that bacteria not only enhance algal growth but also help in flocculation, both essential processes in algal biotechnology. Hence, there is a need to understand these interactions from an evolutionary and ecological standpoint, and integrate this understanding for industrial use. Here we reflect on the diversity of such relationships and their associated mechanisms, as well as the habitats that they mutually influence. This review also outlines the role of these interactions in key evolutionary events such as endosymbiosis, besides their ecological role in biogeochemical cycles. Finally, we focus on extending such studies on algal-bacterial interactions to various environmental and bio-technological applications. PMID:26657897

  4. Extraction of mercury from groundwater using immobilized algae.

    PubMed

    Barkley, N P

    1991-10-01

    Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algal biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into adsorption columns, exhibited excellent flow characteristics, and functioned as a "biological" ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of this product to adsorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded nonrepeatable results with samples collected at different times of the year. The strategy of sequentially extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity. PMID:1777231

  5. Actin gene family dynamics in cryptomonads and red algae.

    PubMed

    Tanifuji, Goro; Archibald, John M

    2010-09-01

    Here we present evidence for a complex evolutionary history of actin genes in red algae and cryptomonads, a group that acquired photosynthesis secondarily through the engulfment of a red algal endosymbiont. Four actin genes were found in the nuclear genome of the cryptomonad, Guillardia theta, and in the genome of the red alga, Galdieria sulphuraria, a member of the Cyanidiophytina. Phylogenetic analyses reveal that the both organisms possess two distinct sequence types, designated "type-1" and "type-2." A weak but consistent phylogenetic affinity between the cryptomonad type-2 sequences and the type-2 sequences of G. sulphuraria and red algae belonging to the Rhodophytina was observed. This is consistent with the possibility that the cryptomonad type-2 sequences are derived from the red algal endosymbiont that gave rise to the cryptomonad nucleomorph and plastid. Red algae as a whole possess two very different actin sequence types, with G. sulphuraria being the only organism thus far known to possess both. The common ancestor of Rhodophytina and Cyanidiophytina may have had two actin genes, with differential loss explaining the distribution of these genes in modern-day groups. Our study provides new insight into the evolution and divergence of actin genes in cryptomonads and red algae, and in doing so underscores the challenges associated with heterogeneity in actin sequence evolution and ortholog/paralog detection.

  6. Boron uptake, localization, and speciation in marine brown algae.

    PubMed

    Miller, Eric P; Wu, Youxian; Carrano, Carl J

    2016-02-01

    In contrast to the generally boron-poor terrestrial environment, the concentration of boron in the marine environment is relatively high (0.4 mM) and while there has been extensive interest in its use as a surrogate of pH in paleoclimate studies in the context of climate change-related questions, the relatively depth independent, and the generally non-nutrient-like concentration profile of this element have led to boron being neglected as a potentially biologically relevant element in the ocean. Among the marine plant-like organisms the brown algae (Phaeophyta) are one of only five lineages of photosynthetic eukaryotes to have evolved complex multicellularity. Many of unusual and often unique features of brown algae are attributable to this singular evolutionary history. These adaptations are a reflection of the marine coastal environment which brown algae dominate in terms of biomass. Consequently, brown algae are of fundamental importance to oceanic ecology, geochemistry, and coastal industry. Our results indicate that boron is taken up by a facilitated diffusion mechanism against a considerable concentration gradient. Furthermore, in both Ectocarpus and Macrocystis some boron is most likely bound to cell wall constituent alginate and the photoassimilate mannitol located in sieve cells. Herein, we describe boron uptake, speciation, localization and possible biological function in two species of brown algae, Macrocystis pyrifera and Ectocarpus siliculosus.

  7. Method to transform algae, materials therefor, and products produced thereby

    DOEpatents

    Dunahay, T.G.; Roessler, P.G.; Jarvis, E.E.

    1997-08-26

    Disclosed is a method to transform chlorophyll C-containing algae. The method includes introducing a recombinant molecule comprising a nucleic acid molecule encoding a dominant selectable marker operatively linked to an algal regulatory control sequence into a chlorophyll C-containing alga in such a manner that the marker is produced by the alga. In a preferred embodiment the algal regulatory control sequence is derived from a diatom and preferably Cyclotella cryptica. Also disclosed is a chimeric molecule having one or more regulatory control sequences derived from one or more chlorophyll C-containing algae operatively linked to a nucleic acid molecule encoding a selectable marker, an RNA molecule and/or a protein, wherein the nucleic acid molecule does not normally occur with one or more of the regulatory control sequences. Further, specifically disclosed are molecules pACCNPT10, pACCNPT4.8 and pACCNPT5.1. The methods and materials of the present invention provide the ability to accomplish stable genetic transformation of chlorophyll C-containing algae. 2 figs.

  8. Method to transform algae, materials therefor, and products produced thereby

    DOEpatents

    Dunahay, Terri Goodman; Roessler, Paul G.; Jarvis, Eric E.

    1997-01-01

    Disclosed is a method to transform chlorophyll C-containing algae which includes introducing a recombinant molecule comprising a nucleic acid molecule encoding a dominant selectable marker operatively linked to an algal regulatory control sequence into a chlorophyll C-containing alga in such a manner that the marker is produced by the alga. In a preferred embodiment the algal regulatory control sequence is derived from a diatom and preferably Cyclotella cryptica. Also disclosed is a chimeric molecule having one or more regulatory control sequences derived from one or more chlorophyll C-containing algae operatively linked to a nucleic acid molecule encoding a selectable marker, an RNA molecule and/or a protein, wherein the nucleic acid molecule does not normally occur with one or more of the regulatory control sequences. Further specifically disclosed are molecules pACCNPT10, pACCNPT4.8 and pACCNPT5.1. The methods and materials of the present invention provide the ability to accomplish stable genetic transformation of chlorophyll C-containing algae.

  9. Algae-bacteria interactions: Evolution, ecology and emerging applications.

    PubMed

    Ramanan, Rishiram; Kim, Byung-Hyuk; Cho, Dae-Hyun; Oh, Hee-Mock; Kim, Hee-Sik

    2016-01-01

    Algae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as varied as deep seas to lichens and represent all conceivable modes of interactions - from mutualism to parasitism. Several studies have shown that algae and bacteria synergistically affect each other's physiology and metabolism, a classic case being algae-roseobacter interaction. These interactions are ubiquitous and define the primary productivity in most ecosystems. In recent years, algae have received much attention for industrial exploitation but their interaction with bacteria is often considered a contamination during commercialization. A few recent studies have shown that bacteria not only enhance algal growth but also help in flocculation, both essential processes in algal biotechnology. Hence, there is a need to understand these interactions from an evolutionary and ecological standpoint, and integrate this understanding for industrial use. Here we reflect on the diversity of such relationships and their associated mechanisms, as well as the habitats that they mutually influence. This review also outlines the role of these interactions in key evolutionary events such as endosymbiosis, besides their ecological role in biogeochemical cycles. Finally, we focus on extending such studies on algal-bacterial interactions to various environmental and bio-technological applications.

  10. Application of algae-biosensor for environmental monitoring.

    PubMed

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

    2015-01-01

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

  11. Method and apparatus using an active ionic liquid for algae biofuel harvest and extraction

    DOEpatents

    Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.; Teixeira, Rodrigo

    2012-11-06

    The invention relates to use of an active ionic liquid to dissolve algae cell walls. The ionic liquid is used to, in an energy efficient manner, dissolve and/or lyse an algae cell walls, which releases algae constituents used in the creation of energy, fuel, and/or cosmetic components. The ionic liquids include ionic salts having multiple charge centers, low, very low, and ultra low melting point ionic liquids, and combinations of ionic liquids. An algae treatment system is described, which processes wet algae in a lysing reactor, separates out algae constituent products, and optionally recovers the ionic liquid in an energy efficient manner.

  12. Aquatic toxicity of four veterinary drugs commonly applied in fish farming and animal husbandry.

    PubMed

    Kołodziejska, Marta; Maszkowska, Joanna; Białk-Bielińska, Anna; Steudte, Stephanie; Kumirska, Jolanta; Stepnowski, Piotr; Stolte, Stefan

    2013-08-01

    Doramectin (DOR), metronidazole (MET), florfenicol (FLO), and oxytetracycline (OXT) are among the most widely used veterinary drugs in animal husbandry or in aquaculture. Contamination of the environment by these pharmaceuticals has given cause for concern in recent years. Even though their toxicity has been thoroughly analyzed, knowledge of their ecotoxicity is still limited. We investigated their aquatic toxicity using tests with marine bacteria (Vibrio fischeri), green algae (Scenedesmus vacuolatus), duckweed (Lemna minor) and crustaceans (Daphnia magna). All the ecotoxicological tests were supported by chemical analyses to confirm the exposure concentrations of the pharmaceuticals used in the toxicity experiments, since deviations from the nominal concentration can result in underestimation of biological effects. It was found that OXT and FLO have a stronger adverse effect on duckweed (EC50=3.26 and 2.96mgL(-1) respectively) and green algae (EC50=40.4 and 18.0mgL(-1)) than on bacteria (EC50=108 and 29.4mgL(-1)) and crustaceans (EC50=114 and 337mgL(-1)), whereas MET did not exhibit any adverse effect in the tested concentration range. For DOR a very low EC50 of 6.37×10(-5)mgL(-1) towards D. magna was determined, which is five orders of magnitude lower than values known for the toxic reference compound K2Cr2O7. Our data show the strong influence of certain veterinary drugs on aquatic organisms and contribute to a sound assessment of the environmental hazards posed by commonly used pharmaceuticals. PMID:23689096

  13. An updated comprehensive techno-economic analysis of algae biodiesel.

    PubMed

    Nagarajan, Sanjay; Chou, Siaw Kiang; Cao, Shenyan; Wu, Chen; Zhou, Zhi

    2013-10-01

    Algae biodiesel is a promising but expensive alternative fuel to petro-diesel. To overcome cost barriers, detailed cost analyses are needed. A decade-old cost analysis by the U.S. National Renewable Energy Laboratory indicated that the costs of algae biodiesel were in the range of $0.53-0.85/L (2012 USD values). However, the cost of land and transesterification were just roughly estimated. In this study, an updated comprehensive techno-economic analysis was conducted with optimized processes and improved cost estimations. Latest process improvement, quotes from vendors, government databases, and other relevant data sources were used to calculate the updated algal biodiesel costs, and the final costs of biodiesel are in the range of $0.42-0.97/L. Additional improvements on cost-effective biodiesel production around the globe to cultivate algae was also recommended. Overall, the calculated costs seem promising, suggesting that a single step biodiesel production process is close to commercial reality.

  14. Stable chloroplast transformation of the unicellular red alga Porphyridium species.

    PubMed

    Lapidot, Miri; Raveh, Dina; Sivan, Alex; Arad, Shoshana Malis; Shapira, Michal

    2002-05-01

    Red algae are extremely attractive for biotechnology because they synthesize accessory photosynthetic pigments (phycobilins and carotenoids), unsaturated fatty acids, and unique cell wall sulfated polysaccharides. We report a high-efficiency chloroplast transformation system for the unicellular red microalga Porphyridium sp. This is the first genetic transformation system for Rhodophytes and is based on use of a mutant form of the gene encoding acetohydroxyacid synthase [AHAS(W492S)] as a dominant selectable marker. AHAS is the target enzyme of the herbicide sulfometuron methyl, which effectively inhibits growth of bacteria, fungi, plants, and algae. Biolistic transformation of synchronized Porphyridium sp. cells with the mutant AHAS(W492S) gene that confers herbicide resistance gave a high frequency of sulfomethuron methyl-resistant colonies. The mutant AHAS gene integrated into the chloroplast genome by homologous recombination. This system paves the way for expression of foreign genes in red algae and has important biotechnological implications.

  15. [Immunostimulating activity of the lipopolysaccharides of blue-green algae].

    PubMed

    Besednova, N N; Smolina, T P; Mikheĭskaia, L V; Ovodova, R G

    1979-12-01

    The whole cells of blue-gree algae and lipopolysaccharides isolated from these cells were shown to stimulate the production of macro-(mainly) and microglobulin antibodies in rabbits. The macro- and microphage indices in rabbits increased significantly after the injection of LPS isolated from blue-green algae 24--48 hours before infecting the animals with a virulent Y. pseudotuberculosis strain. Besides, the inhibiting action of this strain on the migration of phagocytes to the site of infection was abolished immediately after the injection. The use of the indirect hemagglutination test allowed to prove the absence of close antigenic interrelations between blue-green algae and the following organisms: Spirulina platensis, Microcystis aeruginosa, Phormidium africanum and P. uncinatum. PMID:117655

  16. Algae from the arid southwestern United States: an annotated bibliography

    SciTech Connect

    Thomas, W.H.; Gaines, S.R.

    1983-06-01

    Desert algae are attractive biomass producers for capturing solar energy through photosynthesis of organic matter. They are probably capable of higher yields and efficiencies of light utilization than higher plants, and are already adapted to extremes of sunlight intensity, salinity and temperature such as are found in the desert. This report consists of an annotated bibliography of the literature on algae from the arid southwestern United States. It was prepared in anticipation of efforts to isolate desert algae and study their yields in the laboratory. These steps are necessary prior to setting up outdoor algal culture ponds. Desert areas are attractive for such applications because land, sunlight, and, to some extent, water resources are abundant there. References are sorted by state.

  17. Designer proton-channel transgenic algae for photobiological hydrogen production

    DOEpatents

    Lee, James Weifu

    2011-04-26

    A designer proton-channel transgenic alga for photobiological hydrogen production that is specifically designed for production of molecular hydrogen (H.sub.2) through photosynthetic water splitting. The designer transgenic alga includes proton-conductive channels that are expressed to produce such uncoupler proteins in an amount sufficient to increase the algal H.sub.2 productivity. In one embodiment the designer proton-channel transgene is a nucleic acid construct (300) including a PCR forward primer (302), an externally inducible promoter (304), a transit targeting sequence (306), a designer proton-channel encoding sequence (308), a transcription and translation terminator (310), and a PCR reverse primer (312). In various embodiments, the designer proton-channel transgenic algae are used with a gas-separation system (500) and a gas-products-separation and utilization system (600) for photobiological H.sub.2 production.

  18. A look at diacylglycerol acyltransferases (DGATs) in algae.

    PubMed

    Chen, Jit Ern; Smith, Alison G

    2012-11-30

    Triacylglycerols (TAGs) from algae are considered to be a potentially viable source of biodiesel and thereby renewable energy, but at the moment very little is known about the biosynthetic pathway in these organisms. Here we compare what is currently known in eukaryotic algal species, in particular the characteristics of algal diacylglycerol acyltransferase (DGAT), the last enzyme of de novo TAG biosynthesis. Several studies in plants and mammals have shown that there are two DGAT isoforms, DGAT1 and DGAT2, which catalyse the same reaction but have no clear sequence similarities. Instead, they have differences in functionality and spatial and temporal expression patterns. Bioinformatic searches of sequenced algal genomes reveal that most algae have multiple copies of putative DGAT2s, whereas other eukaryotes have single genes. Investigating whether these putative isoforms are indeed functional and whether they confer significantly different phenotypes to algal cells will be vital for future efforts to genetically modify algae for biofuel production.

  19. Synergistic cooperation between wastewater-born algae and activated sludge for wastewater treatment: influence of algae and sludge inoculation ratios.

    PubMed

    Su, Yanyan; Mennerich, Artur; Urban, Brigitte

    2012-02-01

    An algal-bacterial culture, composed of wastewater-born algae and activated sludge, was cultivated to treat domestic wastewater and accumulate biomass simultaneously. The influence of algae and sludge inoculation ratios on the treatment efficiency and the settleability of the accumulated biomass were investigated. There was no significant effect of the inoculation ratios on the chemical oxygen demand removal. Comparatively, the nutrients removal and related mechanism were varied with different inoculation ratios. The highest nitrogen and phosphorus removal efficiencies were observed with 5:1 (algae/sludge) culture (91.0±7.0% and 93.5±2.5%, respectively) within 10 days, which was 5-40% higher and 2-4 days faster than those with other inoculation ratios. The biomass settleability was improved with the assistance of sludge, and the 1:5 (algae/sludge) culture showed the best settleability. Furthermore, 16S rDNA gene analysis showed that the bacterial communities were varying with different algae and sludge inoculation ratios and some specific bacteria were enriched during operation.

  20. Oleosin of subcellular lipid droplets evolved in green algae.

    PubMed

    Huang, Nan-Lan; Huang, Ming-Der; Chen, Tung-Ling L; Huang, Anthony H C

    2013-04-01

    In primitive and higher plants, intracellular storage lipid droplets (LDs) of triacylglycerols are stabilized with a surface layer of phospholipids and oleosin. In chlorophytes (green algae), a protein termed major lipid-droplet protein (MLDP) rather than oleosin on LDs was recently reported. We explored whether MLDP was present directly on algal LDs and whether algae had oleosin genes and oleosins. Immunofluorescence microscopy revealed that MLDP in the chlorophyte Chlamydomonas reinhardtii was associated with endoplasmic reticulum subdomains adjacent to but not directly on LDs. In C. reinhardtii, low levels of a transcript encoding an oleosin-like protein (oleolike) in zygotes-tetrads and a transcript encoding oleosin in vegetative cells transferred to an acetate-enriched medium were found in transcriptomes and by reverse transcription-polymerase chain reaction. The C. reinhardtii LD fraction contained minimal proteins with no detectable oleolike or oleosin. Several charophytes (advanced green algae) possessed low levels of transcripts encoding oleosin but not oleolike. In the charophyte Spirogyra grevilleana, levels of oleosin transcripts increased greatly in cells undergoing conjugation for zygote formation, and the LD fraction from these cells contained minimal proteins, two of which were oleosins identified via proteomics. Because the minimal oleolike and oleosins in algae were difficult to detect, we tested their subcellular locations in Physcomitrella patens transformed with the respective algal genes tagged with a Green Fluorescent Protein gene and localized the algal proteins on P. patens LDs. Overall, oleosin genes having weak and cell/development-specific expression were present in green algae. We present a hypothesis for the evolution of oleosins from algae to plants. PMID:23391579

  1. Aragonitic Pennsylvanian phylloid algae from New Mexico: The missing link

    SciTech Connect

    Kirkland, B.L.; Moore, C.H. Jr. ); Dickson, J.A.D. )

    1991-03-01

    Remarkably well-preserved codiacean algae (Eugonophyllum and Anchicodium) retaining original aragonite are present in the Virgilian Holder Formation, Sacramento Mountains, south-central New Mexico. The algae are preserved in a 20-cm-thick packstone between two thick (> 5m) shale beds. Aragonite is preserved as a felt-like mesh of needles in the algal skeletons, in the shell fragments of molluscs, in the walls of sponges, and in botryoidal and isopachous marine cements. The aragonite is confirmed by X-ray diffraction, by visual inspection of pristine aragonite needles with SEM, and by a high content of Sr as revealed by microprobe analysis. The average Sr content of the algae (9,091 ppm, n = 21) is comparable to modern codiaceans. Preservation of internal structure in Eugonophyllum was previously unknown. The medullary (interior) region of the Eugonophyllum thallus is composed of an aragonite felt punctuated by small (20 {mu}m diameter), parallel utricles. As in modern codiaceans, the utricles in the cortical (exterior) region of the thallus increase in diameter and their bulbous tips coalesce to form the outer cortex of the plant. This occurrence provides a key piece of evidence in support of hypotheses concerning the nature and origin of phylloid algal bioherms. Because the internal structure of most fossil phylloid algae is replaced by sparry mosaic calcite, taxonomic classification has been difficult even at the fundamental level of division (phylum). The authors discovery confirms that at least some ancient phylloid algae resembled the modern green algae Halimeda or Udotea, and lends credibility to the suggestion that ancient phylloid algal mounds are analogous to modern Halimeda mounds of the South Pacific.

  2. [Sedimentary Phosphorus Forms Under Disturbances and Algae in Taihu Lake].

    PubMed

    Chen, Jun; Li, Da-peng; Zhu, Pei-ying; Huang, Yong; Wang, Ren

    2015-12-01

    Sedimentary phosphorus forms were investigated to clarify the release of sedimentary phosphorus forms under the repeated disturbance with the addition of algae at different initial concentrations. The sediments and overlying water were taken from the Meiliang Bay in Taihu Lake. The results showed that the concentrations of NH₄ Cl-P and Res-P decreased, while the content of Fe/Al-P and Ca-P increased without disturbance. In addition, the Ca-P increased with the increase of the initial concentration of algae and the net increase of Ca-P increased by 48% (30 µg · L⁻¹), 66% (60 µg · L⁻¹), 74% (120 µg · L⁻¹), respectively. However, under the disturbance, the NH₄Cl-P and Res-P were significantly reduced, the Fe/Al-P increased significantly. The percentage of Fe/Al-P to Tot-P was up to 66. 2% (average of the 3 experiments with the addition of algae of 30 µg · L⁻¹, 60 µg · L⁻¹ and 120 µg L-¹), it was higher than the value (53.%, average of the 3 experiments) without the disturbance. Moreover, under the disturbance, the percentage of Ca-P to Tot-P was 24.1% (average of the 3 experiments with the addition of algae of 30 µg · L⁻¹, 60 µg⁻¹ and 120 µg · L⁻¹) and it was slightly lower than that (33.0%, average of the 3 experiments) without the disturbance. It is suggested that the coexistence of disturbance and algae facilitated the formation of Fe/Al-P, but the algae accelerated the formation of Ca-P without disturbance.

  3. Oleosin of subcellular lipid droplets evolved in green algae.

    PubMed

    Huang, Nan-Lan; Huang, Ming-Der; Chen, Tung-Ling L; Huang, Anthony H C

    2013-04-01

    In primitive and higher plants, intracellular storage lipid droplets (LDs) of triacylglycerols are stabilized with a surface layer of phospholipids and oleosin. In chlorophytes (green algae), a protein termed major lipid-droplet protein (MLDP) rather than oleosin on LDs was recently reported. We explored whether MLDP was present directly on algal LDs and whether algae had oleosin genes and oleosins. Immunofluorescence microscopy revealed that MLDP in the chlorophyte Chlamydomonas reinhardtii was associated with endoplasmic reticulum subdomains adjacent to but not directly on LDs. In C. reinhardtii, low levels of a transcript encoding an oleosin-like protein (oleolike) in zygotes-tetrads and a transcript encoding oleosin in vegetative cells transferred to an acetate-enriched medium were found in transcriptomes and by reverse transcription-polymerase chain reaction. The C. reinhardtii LD fraction contained minimal proteins with no detectable oleolike or oleosin. Several charophytes (advanced green algae) possessed low levels of transcripts encoding oleosin but not oleolike. In the charophyte Spirogyra grevilleana, levels of oleosin transcripts increased greatly in cells undergoing conjugation for zygote formation, and the LD fraction from these cells contained minimal proteins, two of which were oleosins identified via proteomics. Because the minimal oleolike and oleosins in algae were difficult to detect, we tested their subcellular locations in Physcomitrella patens transformed with the respective algal genes tagged with a Green Fluorescent Protein gene and localized the algal proteins on P. patens LDs. Overall, oleosin genes having weak and cell/development-specific expression were present in green algae. We present a hypothesis for the evolution of oleosins from algae to plants.

  4. Smallest algae thrive as the Arctic Ocean freshens.

    PubMed

    Li, William K W; McLaughlin, Fiona A; Lovejoy, Connie; Carmack, Eddy C

    2009-10-23

    As climate changes and the upper Arctic Ocean receives more heat and fresh water, it becomes more difficult for mixing processes to deliver nutrients from depth to the surface for phytoplankton growth. Competitive advantage will presumably accrue to small cells because they are more effective in acquiring nutrients and less susceptible to gravitational settling than large cells. Since 2004, we have discerned an increase in the smallest algae and bacteria along with a concomitant decrease in somewhat larger algae. If this trend toward a community of smaller cells is sustained, it may lead to reduced biological production at higher trophic levels. PMID:19900890

  5. Algae Biofuels Co-Location Assessment Tool for Canada

    2011-11-29

    The Algae Biofuels Co-Location Assessment Tool for Canada uses chemical stoichiometry to estimate Nitrogen, Phosphorous, and Carbon atom availability from waste water and carbon dioxide emissions streams, and requirements for those same elements to produce a unit of algae. This information is then combined to find limiting nutrient information and estimate potential productivity associated with waste water and carbon dioxide sources. Output is visualized in terms of distributions or spatial locations. Distances are calculated betweenmore » points of interest in the model using the great circle distance equation, and the smallest distances found by an exhaustive search and sort algorithm.« less

  6. Algae Biofuels Co-Location Assessment Tool for Canada

    SciTech Connect

    2011-11-29

    The Algae Biofuels Co-Location Assessment Tool for Canada uses chemical stoichiometry to estimate Nitrogen, Phosphorous, and Carbon atom availability from waste water and carbon dioxide emissions streams, and requirements for those same elements to produce a unit of algae. This information is then combined to find limiting nutrient information and estimate potential productivity associated with waste water and carbon dioxide sources. Output is visualized in terms of distributions or spatial locations. Distances are calculated between points of interest in the model using the great circle distance equation, and the smallest distances found by an exhaustive search and sort algorithm.

  7. ECOLOGY: California Algae May Be Feared European Species.

    PubMed

    Kaiser, J

    2000-07-14

    A volleyball-court-sized patch of bright green algae in a San Diego lagoon has set off alarm bells among ecologists and officials. Scientists strongly suspect that the algae, Caulerpa taxifolia, is the same fast-growing, non-native clone that has swept over the northwestern Mediterranean sea floor in the past decade with devastating ecological consequences. A consortium of agencies and private groups has cordoned off the lagoon and is laying plans to poison the seaweed, marking the first major U.S. attempt to stop an incipient marine species invasion. PMID:17750394

  8. Algae as promising organisms for environment and health

    PubMed Central

    2011-01-01

    Algae, like other plants, produce a variety of remarkable compounds collectively referred to as secondary metabolites. They are synthesized by these organisms at the end of the growth phase and/or due to metabolic alterations induced by environmental stress conditions. Carotenoids, phenolic compounds, phycobiliprotein pigments, polysaccharides and unsaturated fatty acids are same of the algal natural products, which were reported to have variable biological activities, including antioxidant activity, anticancer activity, antimicroabial activity against bacteria-virus-algae-fungi, organic fertilizer and bioremediation potentials. PMID:21862867

  9. Value of crops: Quantity, quality and cost price. [algae as a nutritional supplement

    NASA Technical Reports Server (NTRS)

    Meyer, C.

    1979-01-01

    Possibilities of using algae as a nutritional supplement are examined. The nutritional value and protein content of spirulines of blue algae are discussed. A cost analysis of growing them artificially is presented.

  10. Where Have All the Algae Gone, or, How Many Kingdoms Are There?

    ERIC Educational Resources Information Center

    Blackwell, Will H.; Powell, Martha J.

    1995-01-01

    Examined 10 introductory college-level, general biology survey textbooks for the coverage of algae to assess the efficacy of coverage. Describes a proposal of seven kingdoms and discusses the disposition of algae among five of these kingdoms. Contends that textbooks should highlight the concept of algae across the five kingdoms. Contains 59…

  11. MONITORING CHLOROPHYLL-A AS A MEASURE OF ALGAE IN LAKE WATER

    EPA Science Inventory

    Algae are an important quality component in water bodies. They are photosynthesizing organisms and are the foundation of most aquatic food webs; however, some algae (e.g. blue-green algae) can produce algal toxins. The presence of algal toxins in water bodies has important ...

  12. Biodegradation of phenols by the alga Ochromonas danica.

    PubMed Central

    Semple, K T; Cain, R B

    1996-01-01

    The eukaryotic alga Ochromonas danica, a nutritionally versatile, mixotrophic chrysophyte, grew on phenol as the sole carbon source in axenic culture and removed the phenol carbon from the growth medium. Respirometric studies confirmed that the enzymes involved in phenol catabolism were inducible and that the alga oxidized phenol; the amount of oxygen consumed per mole of oxidized substrate was approximately 65% of the theoretical value. [U-14C]phenol was completely mineralized, with 65% of the 14C label appearing as 14CO2, approximately 15% remaining in the aqueous medium, and the rest accounted for in the biomass. Analysis of the biomass showed that 14C label had been incorporated into the protein, nucleic acid, and lipid fractions; phenol carbon is thus unequivocally assimilated by the alga. Phenol-grown cultures of O. danica converted phenols to the corresponding catechols, which were further metabolized by the meta-cleavage pathway. This surprising result was rigorously confirmed by taking the working stock culture through a variety of procedures to check that it was axenic and repeating the experiments with algal extracts. This is, as far as is known, the first definitive identification of the meta-cleavage pathway for aromatic ring degradation in a eukaryotic alga, though its incidence in other eukaryotes has been (infrequently) suggested. PMID:8919787

  13. Fatty acid amides from freshwater green alga Rhizoclonium hieroglyphicum.

    PubMed

    Dembitsky, V M; Shkrob, I; Rozentsvet, O A

    2000-08-01

    Freshwater green algae Rhizoclonium hieroglyphicum growing in the Ural Mountains were examined for their fatty acid amides using capillary gas chromatography-mass spectrometry (GC-MS). Eight fatty acid amides were identified by GC-MS. (Z)-9-octadecenamide was found to be the major component (2.26%).

  14. Optimization of light use efficiency for biofuel production in algae.

    PubMed

    Simionato, Diana; Basso, Stefania; Giacometti, Giorgio M; Morosinotto, Tomas

    2013-12-01

    A major challenge for next decades is development of competitive renewable energy sources, highly needed to compensate fossil fuels reserves and reduce greenhouse gas emissions. Among different possibilities, which are currently under investigation, there is the exploitation of unicellular algae for production of biofuels and biodiesel in particular. Some algae species have the ability of accumulating large amount of lipids within their cells which can be exploited as feedstock for the production of biodiesel. Strong research efforts are however still needed to fulfill this potential and optimize cultivation systems and biomass harvesting. Light provides the energy supporting algae growth and available radiation must be exploited with the highest possible efficiency to optimize productivity and make microalgae large scale cultivation energetically and economically sustainable. Investigation of the molecular bases influencing light use efficiency is thus seminal for the success of this biotechnology. In this work factors influencing light use efficiency in algal biomass production are reviewed, focusing on how algae genetic engineering and control of light environment within photobioreactors can improve the productivity of large scale cultivation systems.

  15. A simple classification of the volvocine algae by formal languages.

    PubMed

    Yoshida, Hiroshi; Yokomori, Takashi; Suyama, Akira

    2005-11-01

    There are several explanations of why certain primitive multicellular organisms aggregate in particular forms and why their constituent cells cooperate with one another to a particular degree. Utilizing the framework of formal language theory, we have derived one possible simple classification of the volvocine algae-one of the primitive multicells-for some forms of aggregation and some degrees of cooperation among cells. The volvocine algae range from the unicellular Chlamydomonas to the multicellular Volvox globator, which has thousands of cells. The classification we use in this paper is based on the complexity of Parikh sets of families on Chomsky hierarchy in formal language theory. We show that an alga with almost no space closed to the environment, e.g., Gonium pectorale, can be characterized by PsFIN, one with a closed space and no cooperation, e.g., Eudorina elegans, by PsCF, and one with a closed space and cooperation, e.g., Volvox globator, by PslambdauSC. This classification should provide new insights into the necessity for specific forms and degrees of cooperation in the volvocine algae. PMID:16005503

  16. [Phycobiliproteins of blue-green, red and cryptophytic algae].

    PubMed

    Stadnichuk, I N; Gusev, M V

    1979-04-01

    The present-day concepts on phycobiliproteins, the protein pigments of blue-green, red and cryptophyte algae are reviewed. The functions, distribution, localization, physico-chemical, spectral and immunochemical properties of phycobiliproteins are described. The properties of the polypeptide protein subunits and the composition and chemical structure of chromophores as well as their binding to the apoprotein molecules are discussed.

  17. 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

  18. 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.

  19. Survey of Hydrogenase Activity in Algae: Final Report

    SciTech Connect

    Brand, J. J.

    1982-04-01

    The capacity for hydrogen gas production was examined in nearly 100 strains of Eukaryotic algae. Each strain was assessed for rate of H2 production in darkness, at compensating light intensity and at saturating Tight intensity. Maximum H2 yield on illumination and sensitivity to molecular oxygen were also measured.

  20. MicroRNAs in a multicellular green alga Volvox carteri.

    PubMed

    Li, Jingrui; Wu, Yang; Qi, Yijun

    2014-01-01

    microRNAs (miRNAs) have emerged as key components in the eukaryotic gene regulatory network. We and others have previously identified many miRNAs in a unicellular green alga, Chlamydomonas reinhardtii. To investigate whether miRNA-mediated gene regulation is a general mechanism in green algae and how miRNAs have been evolved in the green algal lineage, we examined small RNAs in Volvox carteri, a multicellular species in the same family with Chlamydomonas reinhardtii. We identified 174 miRNAs in Volvox, with many of them being highly enriched in gonidia or somatic cells. The targets of the miRNAs were predicted and many of them were subjected to miRNA-mediated cleavage in vivo, suggesting that miRNAs play regulatory roles in the biology of green algae. Our catalog of miRNAs and their targets provides a resource for further studies on the evolution, biological functions, and genomic properties of miRNAs in green algae. PMID:24369344

  1. Intracellular invasion of green algae in a salamander host

    PubMed Central

    Kerney, Ryan; Kim, Eunsoo; Hangarter, Roger P.; Heiss, Aaron A.; Bishop, Cory D.; Hall, Brian K.

    2011-01-01

    The association between embryos of the spotted salamander (Ambystoma maculatum) and green algae (“Oophila amblystomatis” Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26–44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae through FISH, suggesting that the decline in autofluorescent cells is primarily due to algal cell death within the host. However, early embryonic egg capsules also contained encysted algal cells on the inner capsule wall, and algal 18S rDNA was amplified from adult reproductive tracts, consistent with oviductal transmission of algae from one salamander generation to the next. The invasion of algae into salamander host tissues and cells represents a unique association between a vertebrate and a eukaryotic alga, with implications for research into cell–cell recognition, possible exchange of metabolites or DNA, and potential congruence between host and symbiont population structures. PMID:21464324

  2. Decreased abundance of crustose coralline algae due to ocean acidification

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Andersson, Andreas J; Jokiel, Paul L.; Rodgers, Ku'ulei S.; Mackenzie, Fred T.

    2008-01-01

    Owing to anthropogenic emissions, atmospheric concentrations of carbon dioxide could almost double between 2006 and 2100 according to business-as-usual carbon dioxide emission scenarios1. Because the ocean absorbs carbon dioxide from the atmosphere2, 3, 4, increasing atmospheric carbon dioxide concentrations will lead to increasing dissolved inorganic carbon and carbon dioxide in surface ocean waters, and hence acidification and lower carbonate saturation states2, 5. As a consequence, it has been suggested that marine calcifying organisms, for example corals, coralline algae, molluscs and foraminifera, will have difficulties producing their skeletons and shells at current rates6, 7, with potentially severe implications for marine ecosystems, including coral reefs6, 8, 9, 10, 11. Here we report a seven-week experiment exploring the effects of ocean acidification on crustose coralline algae, a cosmopolitan group of calcifying algae that is ecologically important in most shallow-water habitats12, 13, 14. Six outdoor mesocosms were continuously supplied with sea water from the adjacent reef and manipulated to simulate conditions of either ambient or elevated seawater carbon dioxide concentrations. The recruitment rate and growth of crustose coralline algae were severely inhibited in the elevated carbon dioxide mesocosms. Our findings suggest that ocean acidification due to human activities could cause significant change to benthic community structure in shallow-warm-water carbonate ecosystems.

  3. NADPH oxidases in Eukaryotes: red algae provide new hints!

    PubMed

    Hervé, Cécile; Tonon, Thierry; Collén, Jonas; Corre, Erwan; Boyen, Catherine

    2006-03-01

    The red macro-alga Chondrus crispus is known to produce superoxide radicals in response to cell-free extracts of its green algal pathogenic endophyte Acrochaete operculata. So far, no enzymes involved in this metabolism have been isolated from red algae. We report here the isolation of a gene encoding a homologue of the respiratory burst oxidase gp91(phox) in C. crispus, named Ccrboh. This single copy gene encodes a polypeptide of 825 amino acids. Search performed in available genome and EST algal databases identified sequences showing common features of NADPH oxidases in other algae such as the red unicellular Cyanidioschyzon merolae, the economically valuable red macro-alga Porphyra yezoensis and the two diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana. Domain organization and phylogenetic relationships with plant, animal, fungal and algal NADPH oxidase homologues were analyzed. Transcription analysis of the C. crispus gene revealed that it was over-transcribed during infection of C. crispus gametophyte by the endophyte A. operculata, and after incubation in presence of atrazine, methyl jasmonate and hydroxyperoxides derived from C20 polyunsaturated fatty acids (PUFAs). These results also illustrate the interest of exploring the red algal lineage for gaining insight into the deep evolution of NADPH oxidases in Eukaryotes.

  4. Controlled artificial upwelling in a fjord to combat toxic algae

    NASA Astrophysics Data System (ADS)

    McClimans, T. A.; Hansen, A. H.; Fredheim, A.; Lien, E.; Reitan, K. I.

    2003-04-01

    During the summer, primary production in the surface layers of some fjords depletes the nutrients to the degree that some arts of toxic algae dominate the flora. We describe an experiment employing a bubble curtain to lift significant amounts of nutrient-rich seawater to the light zone and provide an environment in which useful algae can survive. The motivation for the experiment is to provide a local region in which mussels can be cleansed from the effects of toxic algae. Three 100-m long, perforated pipes were suspended at 40 m depth in the Arnafjord, a side arm of the Sognefjord. Large amounts of compressed air were supplied during a period of three weeks. The deeper water mixed with the surface water and flowed from the mixing region at 5 to 15 m depth. Within a few days, the mixture of nutrient-rich water covered most of the inner portion of Arnafjord. Within 10 days, the plankton samples showed that the artificial upwelling produced the desired type of algae and excluded the toxic blooms that were occurring outside the manipulated fjord arm. The project (DETOX) is supported by the Norwegian ministries of Fisheries, Agriculture and Public Administration.

  5. 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.

  6. Fatty acid amides from freshwater green alga Rhizoclonium hieroglyphicum.

    PubMed

    Dembitsky, V M; Shkrob, I; Rozentsvet, O A

    2000-08-01

    Freshwater green algae Rhizoclonium hieroglyphicum growing in the Ural Mountains were examined for their fatty acid amides using capillary gas chromatography-mass spectrometry (GC-MS). Eight fatty acid amides were identified by GC-MS. (Z)-9-octadecenamide was found to be the major component (2.26%). PMID:11014298

  7. Antibiotic activity of lectins from marine algae against marine vibrios.

    PubMed

    Liao, W-R; Lin, J-Y; Shieh, W-Y; Jeng, W-L; Huang, R

    2003-07-01

    Saline and aqueous ethanol extracts of marine algae and the lectins from two red algal species were assayed for their antibiotic activity against marine vibrios. Experimental studies were also carried out on the influence of environmental factors on such activity, using batch cultures. The results indicated that many of the saline extracts of the algal species were active and that the activity was selective against those vibrios assayed. The algal extracts were active against Vibrio pelagius and the fish pathogen V. vulnificus, but inactive against V. neresis. Algal lectins from Eucheuma serra (ESA) and Galaxaura marginata (GMA) strongly inhibited V. vulnificus but were inactive against the other two vibrios. The antibacterial activity of algal extracts was inhibited by pretreatment with various sugars and glycoprotein. Extracts of the two red algae, E. serra and Pterocladia capillacea, in saline and aqueous ethanol, inhibited markedly the growth rate of V. vulnificus at very low concentrations. Culture results indicated that metabolites active against V. vulnificus were invariably produced in P. capillacea over a wide range of temperature, light intensity, and nutritional conditions. Enhanced antibacterial activity occurred when P. capillacea was grown under higher irradiance, severe nutrient stress and moderate temperature (20 degrees C), reflecting the specific antibiotic characteristics of this alga. The strong antibiotic activity of lectins towards fish pathogenic bacteria reveals one of the important roles played by algal lectins, as well as the potential high economic value of those marine algae assayed for aquaculture and for biomedical purposes. PMID:12884128

  8. Ecological assessments with algae: a review and synthesis.

    PubMed

    Stevenson, Jan

    2014-06-01

    Algae have been used for a century in environmental assessments of water bodies and are now used in countries around the world. This review synthesizes recent advances in the field around a framework for environmental assessment and management that can guide design of assessments, applications of phycology in assessments, and refinements of those applications to better support management decisions. Algae are critical parts of aquatic ecosystems that power food webs and biogeochemical cycling. Algae are also major sources of problems that threaten many ecosystems goods and services when abundances of nuisance and toxic taxa are high. Thus, algae can be used to indicate ecosystem goods and services, which complements how algal indicators are also used to assess levels of contaminants and habitat alterations (stressors). Understanding environmental managers' use of algal ecology, taxonomy, and physiology can guide our research and improve its application. Environmental assessments involve characterizing ecological condition and diagnosing causes and threats to ecosystems goods and services. Recent advances in characterizing condition include site-specific models that account for natural variability among habitats to better estimate effects of humans. Relationships between algal assemblages and stressors caused by humans help diagnose stressors and establish targets for protection and restoration. Many algal responses to stressors have thresholds that are particularly important for developing stakeholder consensus for stressor management targets. Future research on the regional-scale resilience of algal assemblages, the ecosystem goods and services they provide, and methods for monitoring and forecasting change will improve water resource management.

  9. Switchable photosystem-II designer algae for photobiological hydrogen production

    DOEpatents

    Lee, James Weifu

    2010-01-05

    A switchable photosystem-II designer algae for photobiological hydrogen production. The designer transgenic algae includes at least two transgenes for enhanced photobiological H.sub.2 production wherein a first transgene serves as a genetic switch that can controls photosystem II (PSII) oxygen evolution and a second transgene encodes for creation of free proton channels in the algal photosynthetic membrane. In one embodiment, the algae includes a DNA construct having polymerase chain reaction forward primer (302), a inducible promoter (304), a PSII-iRNA sequence (306), a terminator (308), and a PCR reverse primer (310). In other embodiments, the PSII-iRNA sequence (306) is replaced with a CF.sub.1-iRNA sequence (312), a streptomycin-production gene (314), a targeting sequence (316) followed by a proton-channel producing gene (318), or a PSII-producing gene (320). In one embodiment, a photo-bioreactor and gas-product separation and utilization system produce photobiological H.sub.2 from the switchable PSII designer alga.

  10. Expression and assembly of a fully active antibody in algae

    NASA Astrophysics Data System (ADS)

    Mayfield, Stephen P.; Franklin, Scott E.; Lerner, Richard A.

    2003-01-01

    Although combinatorial antibody libraries have solved the problem of access to large immunological repertoires, efficient production of these complex molecules remains a problem. Here we demonstrate the efficient expression of a unique large single-chain (lsc) antibody in the chloroplast of the unicellular, green alga, Chlamydomonas reinhardtii. We achieved high levels of protein accumulation by synthesizing the lsc gene in chloroplast codon bias and by driving expression of the chimeric gene using either of two C. reinhardtii chloroplast promoters and 5' and 3' RNA elements. This lsc antibody, directed against glycoprotein D of the herpes simplex virus, is produced in a soluble form by the alga and assembles into higher order complexes in vivo. Aside from dimerization by disulfide bond formation, the antibody undergoes no detectable posttranslational modification. We further demonstrate that accumulation of the antibody can be modulated by the specific growth regime used to culture the alga, and by the choice of 5' and 3' elements used to drive expression of the antibody gene. These results demonstrate the utility of alga as an expression platform for recombinant proteins, and describe a new type of single chain antibody containing the entire heavy chain protein, including the Fc domain.

  11. Complete Chloroplast Genome Sequence of Phagomixotrophic Green Alga Cymbomonas tetramitiformis

    PubMed Central

    Paasch, Amber E.; Graham, Linda E.; Kim, Eunsoo

    2016-01-01

    We report here the complete chloroplast genome sequence of Cymbomonas tetramitiformis strain PLY262, which is a prasinophycean green alga that retains a phagomixotrophic mode of nutrition. The genome is 84,524 bp in length, with a G+C content of 37%, and contains 3 rRNAs, 26 tRNAs, and 76 protein-coding genes. PMID:27313295

  12. Ecological assessments with algae: a review and synthesis.

    PubMed

    Stevenson, Jan

    2014-06-01

    Algae have been used for a century in environmental assessments of water bodies and are now used in countries around the world. This review synthesizes recent advances in the field around a framework for environmental assessment and management that can guide design of assessments, applications of phycology in assessments, and refinements of those applications to better support management decisions. Algae are critical parts of aquatic ecosystems that power food webs and biogeochemical cycling. Algae are also major sources of problems that threaten many ecosystems goods and services when abundances of nuisance and toxic taxa are high. Thus, algae can be used to indicate ecosystem goods and services, which complements how algal indicators are also used to assess levels of contaminants and habitat alterations (stressors). Understanding environmental managers' use of algal ecology, taxonomy, and physiology can guide our research and improve its application. Environmental assessments involve characterizing ecological condition and diagnosing causes and threats to ecosystems goods and services. Recent advances in characterizing condition include site-specific models that account for natural variability among habitats to better estimate effects of humans. Relationships between algal assemblages and stressors caused by humans help diagnose stressors and establish targets for protection and restoration. Many algal responses to stressors have thresholds that are particularly important for developing stakeholder consensus for stressor management targets. Future research on the regional-scale resilience of algal assemblages, the ecosystem goods and services they provide, and methods for monitoring and forecasting change will improve water resource management. PMID:26988318

  13. A simple classification of the volvocine algae by formal languages.

    PubMed

    Yoshida, Hiroshi; Yokomori, Takashi; Suyama, Akira

    2005-11-01

    There are several explanations of why certain primitive multicellular organisms aggregate in particular forms and why their constituent cells cooperate with one another to a particular degree. Utilizing the framework of formal language theory, we have derived one possible simple classification of the volvocine algae-one of the primitive multicells-for some forms of aggregation and some degrees of cooperation among cells. The volvocine algae range from the unicellular Chlamydomonas to the multicellular Volvox globator, which has thousands of cells. The classification we use in this paper is based on the complexity of Parikh sets of families on Chomsky hierarchy in formal language theory. We show that an alga with almost no space closed to the environment, e.g., Gonium pectorale, can be characterized by PsFIN, one with a closed space and no cooperation, e.g., Eudorina elegans, by PsCF, and one with a closed space and cooperation, e.g., Volvox globator, by PslambdauSC. This classification should provide new insights into the necessity for specific forms and degrees of cooperation in the volvocine algae.

  14. Higher plant origins and the phylogeny of green algae.

    PubMed

    Devereux, R; Loeblich, A R; Fox, G E

    1990-07-01

    5S rRNA sequences from six additional green algae lend strong molecular support for the major outlines of higher plant and green algae phylogeny that have been proposed under varying naming conventions by several authors. In particular, the molecular evidence now available unequivocally supports the existence of at least two well-separated divisions of the Chlorobionta: the Chlorophyta and the Streptophyta (i.e., charophytes) (according to the nomenclature of Bremer). The chlamydomonad 5S rRNAs are, however, sufficiently distinct from both clusters that it may ultimately prove preferable to establish a third taxon for them. In support of these conclusions 5S rRNA sequence data now exist for members of four diverse classes of chlorophytes. These sequences all exhibit considerably more phylogenetic affinity to one another than any of them show toward members of the other cluster, the Streptophyta, or the two Chlamydomonas strains. Among the Charophyceae, new 5S rRNA sequences are provided herein for three genera, Spirogyra, Klebsormidium, and Coleochaete. All of these sequences and the previously published Nitella sequence show greater resemblance among themselves and to the higher plants than they do to any of the other green algae examined to date. These results demonstrate that an appropriately named taxon that includes these green algae and the higher plants is strongly justified. The 5S rRNA data lack the resolution needed, however, to unequivocally determine which of several subdivisions of the charophytes is the sister group of the land plants. The evolutionary diversity of Chlamydomonas relative to the other green algae was recognized in earlier 5S rRNA studies but was unanticipated by ultrastructural work.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Photosynthetic H2 metabolism in Chlamydomonas reinhardtii (unicellular green algae).

    PubMed

    Melis, Anastasios

    2007-10-01

    Unicellular green algae have the ability to operate in two distinctly different environments (aerobic and anaerobic), and to photosynthetically generate molecular hydrogen (H2). A recently developed metabolic protocol in the green alga Chlamydomonas reinhardtii permitted separation of photosynthetic O2-evolution and carbon accumulation from anaerobic consumption of cellular metabolites and concomitant photosynthetic H2-evolution. The H2 evolution process was induced upon sulfate nutrient deprivation of the cells, which reversibly inhibits photosystem-II and O2-evolution in their chloroplast. In the absence of O2, and in order to generate ATP, green algae resorted to anaerobic photosynthetic metabolism, evolved H2 in the light and consumed endogenous substrate. This study summarizes recent advances on green algal hydrogen metabolism and discusses avenues of research for the further development of this method. Included is the mechanism of a substantial tenfold starch accumulation in the cells, observed promptly upon S-deprivation, and the regulated starch and protein catabolism during the subsequent H2-evolution. Also discussed is the function of a chloroplast envelope-localized sulfate permease, and the photosynthesis-respiration relationship in green algae as potential tools by which to stabilize and enhance H2 metabolism. In addition to potential practical applications of H2, approaches discussed in this work are beginning to address the biochemistry of anaerobic H2 photoproduction, its genes, proteins, regulation, and communication with other metabolic pathways in microalgae. Photosynthetic H2 production by green algae may hold the promise of generating a renewable fuel from nature's most plentiful resources, sunlight and water. The process potentially concerns global warming and the question of energy supply and demand. PMID:17721788

  16. Recovery of dilute metal ions by biosorption on river algae and its component

    SciTech Connect

    Fujita, Toyohisa; Kogita, Hiroki; Mamiya, Mitsuo; Yen, W.T.

    1995-12-31

    Green algae taken from an acidic mine drainage and blue-green algae take from an alkaline hot spring stream were collected and tested for their ability to recover or remove dilute metal ions. Experimental results demonstrated that unwashed blue-green algae and washed green algae effectively adsorbed base metals ions and eluted the at pH 1. It was also found that washed and dried algae adsorbed precious metal ions more effectively than unwashed algae. For example, the washed and dried blue-green algae was capable of adsorbing 0.31 kg of gold pre kg of algae. The gold from tetrachloroaurate solution which was adsorbed on washed blue-green algae was found to change to a metallic state following initial metal binding. In the case of a dilute gold complex solution leached with thiourea, only a small amount of gold could be captured by algae. Further experiments were conducted on components of the algae, such as alginic acid, agar, cellulose and chitin and mixtures of these components, in order to determine their contribution to metal adsorption characteristics. However, a mixture of these two components demonstrated both good adsorption and desorption characteristics indicating an interaction between the individual components.

  17. Green Algae as Model Organisms for Biological Fluid Dynamics*

    PubMed Central

    Goldstein, Raymond E.

    2015-01-01

    In the past decade the volvocine green algae, spanning from the unicellular Chlamydomonas to multicellular Volvox, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 μm to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms. PMID:26594068

  18. Marine Polysaccharides from Algae with Potential Biomedical Applications

    PubMed Central

    de Jesus Raposo, Maria Filomena; de Morais, Alcina Maria Bernardo; de Morais, Rui Manuel Santos Costa

    2015-01-01

    There is a current tendency towards bioactive natural products with applications in various industries, such as pharmaceutical, biomedical, cosmetics and food. This has put some emphasis in research on marine organisms, including macroalgae and microalgae, among others. Polysaccharides with marine origin constitute one type of these biochemical compounds that have already proved to have several important properties, such as anticoagulant and/or antithrombotic, immunomodulatory ability, antitumor and cancer preventive, antilipidaemic and hypoglycaemic, antibiotics and anti-inflammatory and antioxidant, making them promising bioactive products and biomaterials with a wide range of applications. Their properties are mainly due to their structure and physicochemical characteristics, which depend on the organism they are produced by. In the biomedical field, the polysaccharides from algae can be used in controlled drug delivery, wound management, and regenerative medicine. This review will focus on the biomedical applications of marine polysaccharides from algae. PMID:25988519

  19. Green Algae as Model Organisms for Biological Fluid Dynamics

    NASA Astrophysics Data System (ADS)

    Goldstein, Raymond E.

    2015-01-01

    In the past decade, the volvocine green algae, spanning from the unicellular Chlamydomonas to multicellular Volvox, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 μm to several millimeters), their geometric regularity, the ease with which they can be cultured, and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms.

  20. Determination of aliphatic hydrocarbons in the alga Himanthalia elongata.

    PubMed

    Punín Crespo, M O; Lage Yusty, M A

    2004-02-01

    The algae considered new foods according to Regulation CE 258/97 need a guarantee of their healthfulness before being in the European market. In this work ten samples of the brown alga Himanthalia elongata have been analyzed with the aim of verifying the absence of aliphatic hydrocarbons, due to the ability of the macroalgae to capture lipophilic organic compounds of the marine water coming from accidental or continuous leaks of raw oil and refined products, which happen each year with the growth of the industrialization and the demand of energy. The fat of the samples were Soxhlet extracted using hexane:dichloromethane (1:1) for 7h. The organic fractions were purified using silica microcolumns. The identification and quantification of the aliphatic hydrocarbons have been carried out using gas chromatography (GC) with flame ionization detector (FID). The total hydrocarbon content was between 14.8 and 40.2 microg g(-1) dry weight. PMID:14759670