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Sample records for alga chlorella fusca

  1. Uptake and bioaccumulation of three PCBs by Chlorella fusca

    SciTech Connect

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

    1982-01-01

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

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

    PubMed

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

    2016-01-01

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

  3. Salt stimulated respiration of Chlorella fusca.

    PubMed

    Löppert, H G

    1976-01-01

    ATP contents have been measured before and after addition of KCl (5 mM final concentration) to suspensions of Chlorella in distilled water under different conditions of energy supply. The levels decreased immediately after salt addition and returned to the original values under conditions both of oxidative phosphorylation and of cyclic photophosphorylation, but not under conditions of fermentation. It appears that this decrease in the ATP level is the cause for salt stimulated respiration (S.S.R.). Furthermore, it is shown that cycloheximide and EDTA, which interact with Rb+ uptake (active and ATP-driven) at low salt concentration, also reduce S.S.R. From this parallelism it is concluded that the ATPase involved in Rb+ uptake at low salt concentration is also responsible for S.S.R. at high salt concentration. As S.S.R. provides far more energy than is required for the small influx of ions it is suggested that the ATPase is decoupled by the salt from ion transport.

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

    SciTech Connect

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

    1984-01-01

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

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

    SciTech Connect

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

    1984-01-01

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

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

    PubMed Central

    Krauss, Friedrich; Schäfer, Wolfram; Schmidt, Ahlert

    1984-01-01

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

  7. Effect of Nutrient Starvation under High Irradiance on Lipid and Starch Accumulation in Chlorella fusca (Chlorophyta).

    PubMed

    Jerez, Celia G; Malapascua, José R; Sergejevová, Magda; Figueroa, Félix L; Masojídek

    2016-02-01

    The effect of nitrogen and sulphur limitation under high irradiance (PAR) was studied in the green microalga Chlorella fusca (Chlorophyta) in order to follow lipid and/or starch accumulation. Growth, biomass composition and the changes in photosynthetic activity (in vivo chlorophyll a fluorescence) were followed in the trials. The full nutrient culture showed high biomass production and starch accumulation at Day 1, when photosynthetic activity was high. Gradual deprivation (no nutrients added) became evident when photosynthesis was significantly suppressed (Day 3 onwards), which entailed a decrease of maximum relative electron transport rate (rETRmax) and increase of non-photochemical quenching (NPQ), accompanied by the onset of lipid accumulation and decline in starch content. In N- and S-starved cultures, rETRmax significantly decreased by Day 3, which caused a substantial drop in biomass production, cell number, biovolume and induction of lipid and starch accumulation. High starch content (45-50 % of DW) was found at the initial stage in full nutrient culture and at the stationary phase in nutrient-starved cultures. By the end of the trial, all treatments showed high lipid content (~30 % of DW). The full nutrient culture had higher biomass yield than starved treatments although starch (~0.2 g L(-1) day(-1)) and lipid (~0.15 g L(-1) day(-1) productivities were fairly similar in all the cultures. Our results showed that we could enrich biomass of C. fusca (% DW) in lipids using a two-stage strategy (a nutrient replete stage followed by gradual nutrient limitation) while under either procedure, N- or S-starvation, both high lipid and starch contents could be achieved.

  8. Biosorption of Lead from Wastewater Using Fresh Water Algae Chlorella.

    PubMed

    Kanchana, S; Jeyanthi, J

    2014-04-01

    The potential use of fresh water algae Chlorella to sorb lead ions from wastewater was evaluated in this study. Fourier transform infra-red analysis of algal species revealed the presence of amino, carboxylic, hydroxyl and carbonyl groups, which were responsible for biosorption of lead ions. Batch sorption experiments were performed to determine the effects of contact time, biosorbent dosage and pH on the adsorption of Pb2+ ions. The optimum conditions of biosorbent dosage, pH and contact time were found to be l0 g/L, 5 and 100 min respectively. The applicability of the Langmuir and Freundlich isotherms for representation of the experimental data was investigated. The adsorption of lead ions on the algae Chlorella fitted well with Freundlich isotherm with a very high correlation coefficient.

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

    SciTech Connect

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

    1988-06-01

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

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

    SciTech Connect

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

    1994-04-01

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

  11. Hyaluronan synthesis in virus PBCV-1-infected chlorella-like green algae.

    PubMed

    Graves, M V; Burbank, D E; Roth, R; Heuser, J; DeAngelis, P L; Van Etten, J L

    1999-04-25

    We previously reported that the chlorella virus PBCV-1 genome encodes an authentic, membrane-associated glycosyltransferase, hyaluronan synthase (HAS). Hyaluronan, a linear polysaccharide chain composed of alternating beta1,4-glucuronic acid and beta1, 3-N-acetylglucosamine groups, is present in vertebrates as well as a few pathogenic bacteria. Studies of infected cells show that the transcription of the PBCV-1 has gene begins within 10 min of virus infection and ends at 60-90 min postinfection. The hyaluronan polysaccharide begins to accumulate as hyaluronan-lyase sensitive, hair-like fibers on the outside of the chlorella cell wall by 15-30 min postinfection; by 240 min postinfection, the infected cells are coated with a dense fibrous network. This hyaluronan slightly reduces attachment of a second chlorella virus to the infected algae. An analysis of 41 additional chlorella viruses indicates that many, but not all, produce hyaluronan during infection.

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

    PubMed

    Deng, Lin; Wang, Hongli; Deng, Nansheng

    2006-11-16

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

  13. Accumulation of heavy metals (Cu, Cr, Pb and Cd) in freshwater micro algae (Chlorella sp.).

    PubMed

    Kumar, Rajesh M; Frankilin, J; Raj, Samuel Paul

    2013-07-01

    Some selected micro algae were used for the removal of heavy metals from wastewater. In this present investigation, Chlorella sp was studied for accumulation of heavy metals, namely copper, chromium, lead and cadmium. The salts containing heavy metals were dissolved in Blue Green 11 medium at different concentrations in a glass jar of 10 litre capacity each and subsequently they were bubbled with air for 12 days at a temperature of 33 degrees C and light intensity of 2200 lux. The removal rates of heavy metals were recorded for every 4 days during the experimental period. Chlorella sp. removed 37%, 43% and 67% of copper after 4, 8, 12 days respectively. The percentage removal of chromium was 34%, 43% and 50% respectively at 4, 8, and 12 days. Lead removal rates of Chlorella sp were 56% after 4 days, 69% after 8 days and 77% after 12 days. The reduction of cadmium in the culture medium after 12 days was 93%. From the present investigation, it is concluded that heavy metal removal ability of Chlorella sp. can be exploited for metal detoxification and environmental clean up.

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

    SciTech Connect

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

    1992-10-01

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

  15. Factors affecting seasonal variation of membrane filtration resistance caused by Chlorella algae.

    PubMed

    Babel, Sandhya; Takizawa, Satoshi; Ozaki, Hiroaki

    2002-03-01

    A seasonal fluctuation pattern was observed in membrane filtration resistance by Chlorella algae cultured in open ponds in the tropical environment. In order to investigate the causes of this phenomenon, Chlorella was cultivated under controlled conditions and the cake resistance was measured by batch filtration in dead-end mode. The filtration resistance was found to be a function of environmental conditions. Algae could grow favourably and offered low specific cake resistance (R,s) on the order of 10(11) m/g for the culture temperature from 28 degrees C to 35 degrees C. The algal growth was inhibited and the specific cake resistance increased to the order of 10(12) m/g below or above this optimum temperature range. Strong solar radiation, coupled with high temperatures, also inhibited the growth of algae and resulted in higher specific cake resistance. The specific cake resistance of algae cultured at different temperatures increased with the amount of the extracellular organic matter (EOM) extracted by 0.1 N NaOH. Hence EOM, rather than bacteria present in the mono-algal culture, was considered to be the primary factor affecting the cake resistance. The specific cake resistance increased drastically after actively growing cells were stored in nutrient-free water under dark conditions. However, the resistance was slightly decreased when the algal cells were stored in NSIII nutrient media in a dark room, indicating the effect of nutrient availability on the change of the specific cake resistance under the light-limiting conditions. EOM extracted from the cells kept in the nutrient-free water contained less sugar than the fresh culture, whereas the EOM extracted from the cells stored in the NSIII media contained more sugar. The molecular distribution of the EOM shifted from below 1,000 kDa before storage to more than 2,000 kDa after storage in both the nutrient-free and NSIII media.

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

    PubMed

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

    2014-06-01

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

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

    PubMed

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

    2016-11-01

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

  18. Inorganic carbon acquisition in the acid-tolerant alga Chlorella kessleri.

    PubMed

    El-Ansari, Omar; Colman, Brian

    2015-01-01

    The ability of the freshwater alga, Chlorella kessleri, to maintain a carbon concentrating mechanism when grown at acid pH was investigated. The alga grows over the pH range 4.0-9.0 and was found to take up bicarbonate and CO2 actively when grown at pH 6.0. However, when grown at acid pH (below 5.5), it does not have active CO2 uptake. The acidotolerant species maintained an internal pH of 6.1-7.5 over the external pH range 4.5-7.5, thus the pH difference between the cell interior and the external medium was large enough to allow for the diffusive uptake of CO2 at acid external pH. Mass spectrometric monitoring of O2 and CO2 fluxes by suspensions of C. kessleri, grown at acid pH, and maintained at pH 7.5 showed that the rates of O2 evolution did not exceed those of CO2 uptake. The final CO2 compensation concentrations of 14.0-17.7 µM reached by photosynthetic cells were above the CO2 equilibrium concentration in the external medium, indicating a lack of active CO2 uptake at acid pH. Chlorella kessleri accumulated CO2 with internal concentrations that were 9.9, 18.7 and 22.7-fold that of the external medium for cells grown, respectively, at pH 4.5, 5.0 and 5.5. The ability of C. kessleri cells to accumulate high intracellular concentrations of inorganic carbon at acid pH would provide a sufficiently high concentration of CO2 at the active site of Rubisco thus allowing the alga to maintain growth rates similar to those at alkaline pH.

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

    PubMed

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

    2015-05-01

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

  20. Technique for harvesting unicellular algae using colloidal gas aphrons. [Chlorella vulgaris

    SciTech Connect

    Honeycutt, S.S.; Wallis, D.A.; Sebba, F.

    1983-01-01

    A novel technique using colloidal gas aphron (CGA) dispersions has been investigated for harvesting Chlorella vulgaris, a unicellular green algae, from dilute suspension. CGA are very small gas bubbles, on the order of 25 ..mu..m in diameter, that are each encapsulated in an aqueous shell of surfactant solution. The process is based on the technology of CGA flotation, which involves the formation of algae-bubble complexes and their subsequent flotation to the surface. At neutral pH, the efficiency of algae removal was maximized when a cationic surfactant (lauryl pyridinium chloride) was used for CGA generation. At pH 10, both the cationic and anionic (sodium dodecyl benzene sulfonate) CGA dispersions yielded comparable removals. Addition of small quantities of alum (to 10/sup -4/M) improved removals using the cationic CGA, and at pH 10 this combination yielded the maximum removals that were achieved: 52.1% removal after a single application of CGA dispersion (1 to 1, dispersion to sample volume ratio), and 89.2% removal after an additional application. 12 references, 1 figure, 2 tables.

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

    PubMed Central

    Ahmad, Iftikhar; Hellebust, Johan A.

    1984-01-01

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

  2. Osmoregulation in the Extremely Euryhaline Marine Micro-Alga Chlorella autotrophica.

    PubMed

    Ahmad, I; Hellebust, J A

    1984-04-01

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

  3. Impact of excipients in the chronic toxicity of fluoxetine on the alga Chlorella vulgaris.

    PubMed

    Silva, Aurora; Santos, Lúcia H M L M; Delerue-Matos, Cristina; Figueiredo, Sónia A

    2014-01-01

    Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) widely used in the treatment of major depression. It has been detected in surface and wastewaters, being able to negatively affect aquatic organisms. Most of the ecotoxicity studies focused only in pharmaceuticals, though excipients can also pose a risk to non-target organisms. In this work the ecotoxicity of five medicines (three generic formulations and two brand labels) containing the same active substance (fluoxetine hydrochloride) was tested on the alga Chlorella vulgaris, in order to evaluate if excipients can influence their ecotoxicity. Effective concentrations that cause 50% of inhibition (EC50) ranging from 0.25 to 15 mg L⁻¹ were obtained in the growth inhibition test performed for the different medicines. The corresponding values for fluoxetine concentration are 10 times lower. Higher EC50 values had been published for the same alga considering only the toxicity of fluoxetine. Therefore, this increase in toxicity may be attributed to the presence of excipients. Thus more studies on ecotoxicological effects of excipients are required in order to assess the environmental risk they may pose to aquatic organisms.

  4. Ecotoxicity tests using the green algae Chlorella vulgaris--a useful tool in hazardous effluents management.

    PubMed

    Silva, Aurora; Figueiredo, Sónia A; Sales, M Goreti; Delerue-Matos, Cristina

    2009-08-15

    The treatment efficiency of laboratory wastewaters was evaluated and ecotoxicity tests with Chlorella vulgaris were performed on them to assess the safety of their environmental discharge. For chemical oxygen demand wastewaters, chromium (VI), mercury (II) and silver were efficiently removed by chemical treatments. A reduction of ecotoxicity was achieved; nevertheless, an EC50 (effective concentration that causes a 50% inhibition in the algae growth) of 1.5% (v/v) indicated still high level of ecotoxicity. For chloride determination wastewaters, an efficient reduction of chromium and silver was achieved after treatment. Regarding the reduction of ecotoxicity observed, EC50 increased from 0.059% to 0.5%, only a 0.02% concentration in the aquatic environment would guarantee no effects. Wastewaters containing phenanthroline/iron (II) complex were treated by chemical oxidation. Treatment was satisfactory concerning chemical parameters, although an increase in ecotoxicity was observed (EC50 reduced from 0.31% to 0.21%). The wastes from the kinetic study of persulphate and iodide reaction were treated with sodium bisulphite until colour was removed. Although they did not reveal significant ecotoxicity, only over 1% of the untreated waste produced observable effects over algae. Therefore, ecotoxicity tests could be considered a useful tool not only in laboratory effluents treatment, as shown, but also in hazardous wastewaters management.

  5. Release of reduced inorganic selenium species into waters by the green fresh water algae Chlorella vulgaris.

    PubMed

    Simmons, Denina Bobbie Dawn; Wallschläger, Dirk

    2011-03-15

    The common green fresh water algae Chlorella vulgaris was exposed to starting concentrations of 10 μg/L selenium in the form of selenate, selenite, or selenocyanate (SeCN(-)) for nine days in 10% Bold's basal medium. Uptake of selenate was more pronounced than that of selenite, and there was very little uptake of selenocyanate. Upon uptake of selenate, significant quantities of selenite and selenocyanate were produced by the algae and released back into the growth medium; no selenocyanate was released after selenite uptake. Release of the reduced metabolites after selenate exposure appeared to coincide with increasing esterase activity in solution, indicating that cell death (lysis) was the primary emission pathway. This is the first observation of biotic formation of selenocyanate and its release into waters from a nonindustrial source. The potential environmental implications of this laboratory observation are discussed with respect to the fate of selenium in impacted aquatic systems, the ecotoxicology of selenium bioaccumulation, and the interpretation of environmental selenium speciation data generated, using methods incapable of positively identifying reduced inorganic selenium species, such as selenocyanate.

  6. Cultivation of green algae Chlorella sp. in different wastewaters from municipal wastewater treatment plant.

    PubMed

    Wang, Liang; Min, Min; Li, Yecong; Chen, Paul; Chen, Yifeng; Liu, Yuhuan; Wang, Yingkuan; Ruan, Roger

    2010-10-01

    The objective of this study was to evaluate the growth of green algae Chlorella sp. on wastewaters sampled from four different points of the treatment process flow of a local municipal wastewater treatment plant (MWTP) and how well the algal growth removed nitrogen, phosphorus, chemical oxygen demand (COD), and metal ions from the wastewaters. The four wastewaters were wastewater before primary settling (#1 wastewater), wastewater after primary settling (#2 wastewater), wastewater after activated sludge tank (#3 wastewater), and centrate (#4 wastewater), which is the wastewater generated in sludge centrifuge. The average specific growth rates in the exponential period were 0.412, 0.429, 0.343, and 0.948 day(-1) for wastewaters #1, #2, #3, and #4, respectively. The removal rates of NH4-N were 82.4%, 74.7%, and 78.3% for wastewaters #1, #2, and #4, respectively. For #3 wastewater, 62.5% of NO3-N, the major inorganic nitrogen form, was removed with 6.3-fold of NO2-N generated. From wastewaters #1, #2, and #4, 83.2%, 90.6%, and 85.6% phosphorus and 50.9%, 56.5%, and 83.0% COD were removed, respectively. Only 4.7% was removed in #3 wastewater and the COD in #3 wastewater increased slightly after algal growth, probably due to the excretion of small photosynthetic organic molecules by algae. Metal ions, especially Al, Ca, Fe, Mg, and Mn in centrate, were found to be removed very efficiently. The results of this study suggest that growing algae in nutrient-rich centrate offers a new option of applying algal process in MWTP to manage the nutrient load for the aeration tank to which the centrate is returned, serving the dual roles of nutrient reduction and valuable biofuel feedstock production.

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed Central

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

    2004-01-01

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

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

    PubMed

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

    2004-09-22

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

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

    NASA Technical Reports Server (NTRS)

    Mills, W. Ronald

    2003-01-01

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

  11. Optimising the bioreceptivity of porous glass tiles based on colonization by the alga Chlorella vulgaris.

    PubMed

    Ferrándiz-Mas, V; Bond, T; Zhang, Z; Melchiorri, J; Cheeseman, C R

    2016-09-01

    Green façades on buildings can mitigate greenhouse gas emissions. An option to obtain green facades is through the natural colonisation of construction materials. This can be achieved by engineering bioreceptive materials. Bioreceptivity is the susceptibility of a material to be colonised by living organisms. The aim of this research was to develop tiles made by sintering granular waste glass that were optimised for bioreceptivity of organisms capable of photosynthesis. Tiles were produced by pressing recycled soda-lime glass with a controlled particle size distribution and sintering compacted samples at temperatures between 680 and 740°C. The primary bioreceptivity of the tiles was evaluated by quantifying colonisation by the algae Chlorella vulgaris (C. vulgaris), which was selected as a model photosynthetic micro-organism. Concentrations of C. vulgaris were measured using chlorophyll-a extraction. Relationships between bioreceptivity and the properties of the porous glass tile, including porosity, sorptivity, translucency and pH are reported. Capillary porosity and water sorptivity were the key factors influencing the bioreceptivity of porous glass. Maximum C. vulgaris growth and colonisation was obtained for tiles sintered at 700°C, with chlorophyll-a concentrations reaching up to 11.1±0.4μg/cm(2) of tile. Bioreceptivity was positively correlated with sorptivity and porosity and negatively correlated with light transmittance. The research demonstrates that the microstructure of porous glass, determined by the processing conditions, significantly influences bioreceptivity. Porous glass tiles with high bioreceptivity that are colonised by photosynthetic algae have the potential to form carbon-negative façades for buildings and green infrastructure.

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

    PubMed

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

    2000-10-01

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

  13. The growth response of the green alga Chlorella vulgaris to combined divalent cation exposure.

    PubMed

    Rachlin, J W; Grosso, A

    1993-01-01

    Using the growth response of the green alga Chlorella vulgaris as a model system, the effects of combinations of the environmentally active cations Cd, Co, and Cu were evaluated. The 96-h static EC50 for these cations to C. vulgaris were, respectively, 0.89 microM, 9.0 microM, and 2.8 microM, yielding a toxicity series such that Cd > Cu > Co. The cation combinations of Cd + Cu, and Cu + Co acted synergistically, while Cd + Co, and the tri-metallic combination Cd + Cu + Co resulted in antagonistic interactions. Examination of these toxic combinations at 24, 48, 72, and 96 h indicate that the cellular response is not a uniform one. Failure of energy dispersive X-ray spectrophotometric analysis to demonstrate any intracellular incorporation of these cations (except for a weak cytoplasmic Cu peak at the 8.0 KEV position) suggests that the toxic actions of these cations at EC50 concentrations are exerted at the level of the plasma membrane.

  14. Kinetic flux profiling dissects nitrogen utilization pathways in the oleaginous green alga Chlorella protothecoides.

    PubMed

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

    2016-02-01

    As a promising candidate for biodiesel production, the green alga Chlorella protothecoides can efficiently produce oleaginous biomass and the lipid biosynthesis is greatly influenced by the availability of nitrogen source and corresponding nitrogen assimilation pathways. Based on isotope-assisted kinetic flux profiling (KFP), the fluxes through the nitrogen utilization pathway were quantitatively analyzed. We found that autotrophic C. protothecoides cells absorbed ammonium mainly through glutamate dehydrogenase (GDH), and partially through glutamine synthetase (GS), which was the rate-limiting enzyme of nitrogen assimilation process with rare metabolic activity of glutamine oxoglutarate aminotransferase (GOGAT, also known as glutamate synthase); whereas under heterotrophic conditions, the cells adapted to GS-GOGAT cycle for nitrogen assimilation in which GS reaction rate was associated with GOGAT activity. The fact that C. protothecoides chooses the adenosine triphosphate-free and less ammonium-affinity GDH pathway, or alternatively the energy-consuming GS-GOGAT cycle with high ammonium affinity for nitrogen assimilation, highlights the metabolic adaptability of C. protothecoides exposed to altered nitrogen conditions.

  15. Algae-facilitated chemical phosphorus removal during high-density Chlorella emersonii cultivation in a membrane bioreactor.

    PubMed

    Xu, Meng; Bernards, Matthew; Hu, Zhiqiang

    2014-02-01

    An algae-based membrane bioreactor (A-MBR) was evaluated for high-density algae cultivation and phosphorus (P) removal. The A-MBR was seeded with Chlorella emersonii and operated at a hydraulic retention time of 1day with minimal biomass wastage for about 150days. The algae concentration increased from initially 385mg/L (or 315mg biomass COD/L) to a final of 4840mg/L (or 1664mg COD/L), yielding an average solids (algae biomass+minerals) production rate of 32.5gm(-3)d(-1) or 6.2gm(-2)d(-1). The A-MBR was able to remove 66±9% of the total P from the water while the algal biomass had an average of 7.5±0.2% extracellular P and 0.4% of intracellular P. The results suggest that algae-induced phosphate precipitation by algae is key to P removal and high-density algae cultivation produces P-rich algal biomass with excellent settling properties.

  16. The effect of cadmium on the growth and antioxidant response for freshwater algae Chlorella vulgaris.

    PubMed

    Cheng, Jinfeng; Qiu, Hongchen; Chang, Zhaoyang; Jiang, Zaimin; Yin, Wenke

    2016-01-01

    The objective of the present work was to evaluate the effect of exogenously applied cadmium on the physiological response of green algae Chlorella vulgaris. The study investigated the long-term effect (18 days) of cadmium on the levels of algae biomass, assimilation pigment composition, soluble protein, oxidative status (production of hydrogen peroxide and superoxide anion), antioxidant enzymes (such as superoxide dismutase, peroxidase, catalase and glutathione reductase enzyme) in C. vulgaris. The results showed that growth, the amount of chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids gradually decreased with increasing cadmium over 18 days exposure. Cadmium at concentration of 7 mg L(-1) inhibited algal growth expressed as the number of cells. Our research found that C. vulgaris has a high tolerance to cadmium. Contents of chlorophylls (Chl a and Chl b) and carotenoids (Car) of C. vulgaris was significantly decline with rising concentration of cadmium (p < 0.05). The decrease of 54.04 and 93.37 % in Chl a, 60.65 and 74.32 % in Chl b, 50.00 and 71.88 % in total carotenoids was noticed following the treatment with 3 and 7 mg L(-1) cadmium doses compared with control treatment, respectively. Cadmium treatments caused a significant change in the physiological competence (calculated as chlorophyll a/b) which increased with increasing Cd(II) doses up to 1 mg L(-1) but decreased at 3 mg L(-1). While accumulation of soluble protein was enhanced by presence of cadmium, the treatment with cadmium at 3 and 7 mg L(-1) increased the concentration of soluble proteins by 88, 95.8 % in C. vulgaris, respectively. Moreover, low doses of cadmium stimulated enzymatic (superoxide dismutase, catalase and glutathione reductase) in C. vulgaris, The content of peroxidase increased with the increasing cadmium concentration, and had slightly decreased at the concentration of 7 mg L(-1), but was still higher than control group, which showed that cadmium

  17. Single and mixture toxicity of pharmaceuticals and chlorophenols to freshwater algae Chlorella vulgaris.

    PubMed

    Geiger, Elisabeth; Hornek-Gausterer, Romana; Saçan, Melek Türker

    2016-07-01

    Organisms in the aquatic environment are exposed to a variety of substances of numerous chemical classes. The unintentional co-occurrence of pharmaceuticals and other contaminants of emerging concern may pose risk to non-target organisms. In this study, individual and binary mixture toxicity experiments of selected pharmaceuticals (ibuprofen and ciprofloxacin) and chlorophenols (2.4-dichlorophenol (2,4-DCP) and 3-chlorophenol (3-CP)) have been performed with freshwater algae Chlorella vulgaris. All experiments have been carried out according to the 96-h algal growth inhibition test OECD No. 201. Binary mixture tests were conducted using proportions of the respective IC50s in terms of toxic unit (TU). The mixture concentration-response curve was compared to predicted effects based on both the concentration addition (CA) and the independent action (IA) model. Additionally, the Combination Index (CI)-isobologram equation method was used to assess toxicological interactions of the binary mixtures. All substances individually tested had a significant effect on C. vulgaris population density and revealed IC50 values <100mgL(-1) after exposure period of 96-h. The toxic ranking of these four compounds to C. vulgaris was 2,4-DCP>ciprofloxacin>3-CP>ibuprofen. Generally, it can be concluded from this study that toxic mixture effects of all tested chemicals to C. vulgaris are higher than the individual effect of each mixture component. It could be demonstrated that IC50 values of the tested mixtures predominately lead to additive effects. The CA model is appropriate to estimate mixture toxicity, while the IA model tends to underestimate the joint effect. The CI-isobologram equation method predicted the mixtures accurately and elicited synergism at low effect levels for the majority of tested combinations.

  18. The influence of extracellular compounds produced by selected Baltic cyanobacteria, diatoms and dinoflagellates on growth of green algae Chlorella vulgaris

    NASA Astrophysics Data System (ADS)

    Żak, Adam; Kosakowska, Alicja

    2015-12-01

    Secondary metabolites produced by bacteria, fungi, algae and plants could affect the growth and development of biological and agricultural systems. This natural process that occurs worldwide is known as allelopathy. The main goal of this work was to investigate the influence of metabolites obtained from phytoplankton monocultures on the growth of green algae Chlorella vulgaris. We selected 6 species occurring in the Baltic Sea from 3 different taxonomic groups: cyanobacteria (Aphanizomenon flos-aquae; Planktothrix agardhii), diatoms (Thalassiosira pseudonana; Chaetoceros wighamii) and dinoflagellates (Alexandrium ostenfeldii; Prorocentrum minimum). In this study we have demonstrated that some of selected organisms caused allelopathic effects against microalgae. Both the negative and positive effects of collected cell-free filtrates on C. vulgaris growth, chlorophyll a concentration and fluorescence parameters (OJIP, QY, NPQ) have been observed. No evidence has been found for the impact on morphology and viability of C. vulgaris cells.

  19. Selenium Accumulation in Unicellular Green Alga Chlorella vulgaris and Its Effects on Antioxidant Enzymes and Content of Photosynthetic Pigments

    PubMed Central

    Sun, Xian; Zhong, Yu; Huang, Zhi; Yang, Yufeng

    2014-01-01

    The aim of the present study was to investigate selenite effects in the unicellular green algae Chlorella vulgaris as a primary producer and the relationship with intracellular bioaccumulation. The effects of selenite were evaluated by measuring the effect of different selenite concentrations on algal growth during a 144 h exposure period. It was found that lower Se concentrations (≤75 mg L−1) positively promoted C. vulgaris growth and acted as antioxidant by inhibiting lipid peroxidation (LPO) and intracellular reactive oxygen species (ROS). The antioxidative effect was associated with an increase in guaiacol peroxidase (GPX), catalase (CAT), superoxide dismutase (SOD) and photosynthetic pigments. Meanwhile, significant increase in the cell growth rate and organic Se content was also detected in the algae. In contrast, these changes were opposite in C. vulgaris exposed to Se higher than 100 mg L−1. The antioxidation and toxicity appeared to be correlated to Se bioaccumulation, which suggests the appropriate concentration of Se in the media accumulation of C. vulgaris should be 75 mg L−1. Taken together, C. vulgaris possesses tolerance to Se, and Se-Chlorella could be developed as antioxidative food for aquaculture and human health. PMID:25375113

  20. Selenium accumulation in unicellular green alga Chlorella vulgaris and its effects on antioxidant enzymes and content of photosynthetic pigments.

    PubMed

    Sun, Xian; Zhong, Yu; Huang, Zhi; Yang, Yufeng

    2014-01-01

    The aim of the present study was to investigate selenite effects in the unicellular green algae Chlorella vulgaris as a primary producer and the relationship with intracellular bioaccumulation. The effects of selenite were evaluated by measuring the effect of different selenite concentrations on algal growth during a 144 h exposure period. It was found that lower Se concentrations (≤ 75 mg L(-1)) positively promoted C. vulgaris growth and acted as antioxidant by inhibiting lipid peroxidation (LPO) and intracellular reactive oxygen species (ROS). The antioxidative effect was associated with an increase in guaiacol peroxidase (GPX), catalase (CAT), superoxide dismutase (SOD) and photosynthetic pigments. Meanwhile, significant increase in the cell growth rate and organic Se content was also detected in the algae. In contrast, these changes were opposite in C. vulgaris exposed to Se higher than 100 mg L-1. The antioxidation and toxicity appeared to be correlated to Se bioaccumulation, which suggests the appropriate concentration of Se in the media accumulation of C. vulgaris should be 75 mg L-1. Taken together, C. vulgaris possesses tolerance to Se, and Se-Chlorella could be developed as antioxidative food for aquaculture and human health.

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

    PubMed

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

    2016-08-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

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

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

    PubMed Central

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

    2009-01-01

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

  5. Toxicity of Cu (II) to the green alga Chlorella vulgaris: a perspective of photosynthesis and oxidant stress.

    PubMed

    Chen, Zunwei; Song, Shufang; Wen, Yuezhong; Zou, Yuqin; Liu, Huijun

    2016-09-01

    The toxic effects of Cu (II) on the freshwater green algae Chlorella vulgaris and its chloroplast were investigated by detecting the responses of photosynthesis and oxidant stress. The results showed that Cu (II) arrested the growth of C. vulgaris and presented in a concentration- and time-dependent trend and the SRichards 2 model fitted the inhibition curve best. The chlorophyll fluorescence parameters, including qP, Y (II), ETR, F v /F m , and F v /F 0, were stimulated at low concentration of Cu (II) but declined at high concentration, indicating the photosystem II (PSII) of C. vulgaris was destroyed by Cu (II). The chloroplasts were extracted, and the Hill reaction activity (HRA) of chloroplast was significantly decreased with the increasing Cu (II) concentration under both illuminating and dark condition, and faster decline speed was observed under dark condition. Activities of superoxide dismutase (SOD) and catalase (CAT) and malondialdehyde (MDA) content were also significantly decreased at high concentration Cu (II), companied with a large number of reactive oxygen species (ROS) production. All these results indicated a severe oxidative stress on algal cells occurred as well as the effect on photosynthesis, thus inhibiting the growth of algae, which providing sights to evaluate the phytotoxicity of Cu (II).

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

    PubMed

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

    2015-07-01

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

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

    PubMed

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

    2015-07-01

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

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

    PubMed

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

    2016-10-01

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

  9. 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.

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

    PubMed

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

    2016-05-01

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

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

    PubMed

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

    2015-05-01

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

  13. Optimization of the biomass production of oil algae Chlorella minutissima UTEX2341.

    PubMed

    Li, ZhaoSheng; Yuan, HongLi; Yang, JinShui; Li, BaoZhen

    2011-10-01

    High production cost is a major obstacle to the extensive use of microalgae biodiesel. To cut the cost and achieve higher biomass productivity, Chlorella minutissima UTEX2341 was cultured under photoheterotrophic conditions. With the carbon, nitrogen and phosphorus concentration of 26.37, 2.61 and 0.03 g L⁻¹ d⁻¹ respectively, a maximum biomass productivity of 1.78 g L⁻¹ d⁻¹ was obtained, which was 59 times more than that cultured under autotrophic condition. The lipid productivity reached 0.29 g L⁻¹ d⁻¹, which was 11.9 times higher than the highest value reported by Oh et al. (2010). The conversion rate of microalgae lipids to FAME was found to be elevated from 45.65% to 62.97% and the FAME productivity increased from 1.16 to 180.68 mg L⁻¹ d⁻¹ after the optimization. 94% of the fatty acid of C. minutissima UTEX2341 was found to be composed of palmitic, oleic, linoleic and γ linoleic and the unsaturated fatty acids were the main parts (79.42%).

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

    PubMed

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

    2014-09-02

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

  15. Phytohormones as regulators of heavy metal biosorption and toxicity in green alga Chlorella vulgaris (Chlorophyceae).

    PubMed

    Piotrowska-Niczyporuk, Alicja; Bajguz, Andrzej; Zambrzycka, Elżbieta; Godlewska-Żyłkiewicz, Beata

    2012-03-01

    The present study was undertaken to test the influence of exogenously applied phytohormones: auxins (IAA, IBA, NAA, PAA), cytokinins (BA, CPPU, DPU, 2iP, Kin, TDZ, Z), gibberellin (GA(3)), jasmonic acid (JA) as well as polyamine - spermidine (Spd) upon the growth and metabolism of green microalga Chlorella vulgaris (Chlorophyceae) exposed to heavy metal (Cd, Cu, Pb) stress. The inhibitory effect of heavy metals on algal growth, metabolite accumulation and enzymatic as well as non-enzymatic antioxidant system was arranged in the following order: Cd > Pb > Cu. Exogenously applied phytohormones modify the phytotoxicity of heavy metals. Auxins, cytokinins, gibberellin and spermidine (Spd) can alleviate stress symptoms by inhibiting heavy metal biosorption, restoring algal growth and primary metabolite level. Moreover, these phytohormones and polyamine stimulate antioxidant enzymes' (superoxide dismutase, ascorbate peroxidase, catalase) activities and ascorbate as well as glutathione accumulation by producing increased antioxidant capacity in cells growing under abiotic stress. Increased activity of antioxidant enzymes reduced oxidative stress expressed by lipid peroxidation and hydrogen peroxide level. In contrast JA enhanced heavy metal toxicity leading to increase in metal biosorption and ROS generation. The decrease in cell number, chlorophylls, carotenoids, monosaccharides, soluble proteins, ascorbate and glutathione content as well as antioxidant enzyme activity was also obtained in response to JA and heavy metals. Determining the stress markers (lipid peroxidation, hydrogen peroxide) and antioxidants' level as well as antioxidant enzyme activity in cells is important for understanding the metal-specific mechanisms of toxicity and that these associated novel endpoints may be useful metrics for accurately predicting toxicity. The data suggest that phytohormones and polyamine play an important role in the C. vulgaris responding to abiotic stressor and algal

  16. The role of phosphorus in the metabolism of arsenate by a freshwater green alga, Chlorella vulgaris.

    PubMed

    Baker, Josh; Wallschläger, Dirk

    2016-11-01

    A freshwater microalga, Chlorella vulgaris, was grown in the presence of varying phosphate concentrations (<10-500μg/L P) and environmentally realistic concentrations of arsenate (As(V)) (5-50μg/L As). Arsenic speciation in the culture medium and total cellular arsenic were measured using AEC-ICP-MS and ICP-DRC-MS, respectively, to determine arsenic biotransformation and uptake in the various phosphorus scenarios. At high phosphate concentration in the culture medium, >100μg/L P, the uptake and biotransformation of As(V) was minimal and dimethylarsonate (DMAs(V)) was the dominant metabolite excreted by C. vulgaris, albeit at relatively low concentrations. At common environmental P concentrations, 0-50μg/L P, the uptake and biotransformation of As(V) increased. At these higher As-uptake levels, arsenite (As(III)) was the predominant metabolite excreted from the cell. The concentrations of As(III) in these low P conditions were much higher than the concentrations of methylated arsenicals observed at the various P concentrations studied. The switchover threshold between the (small) methylation and (large) reduction of As(V) occurred around a cellular As concentration of 1fg/cell. The observed nearly quantitative conversion of As(V) to As(III) under low phosphate conditions indicates the importance of As(V) bio-reduction at common freshwater P concentrations. These findings on the influence of phosphorus on arsenic uptake, accumulation and excretion are discussed in relation to previously published research. The impact that the two scenarios of As(V) metabolism, As(III) excretion at high As(V)-uptake and methylarsenical excretion at low As(V)-uptake, have on freshwater arsenic speciation is discussed.

  17. Model based analysis of transient fluorescence yield induced by actinic laser flashes in spinach leaves and cells of green alga Chlorella pyrenoidosa Chick.

    PubMed

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

    2014-04-01

    Measurements of Single Flash Induced Transient Fluorescence Yield (SFITFY) on spinach leaves and whole cells of green thermophilic alga Chlorella pyrenoidosa Chick were analyzed for electron transfer (ET) steps and coupled proton transfer (PT) on both the donor and the acceptor side of the reaction center (RC) of photosystem II (PS II). A specially developed PS II model (Belyaeva et al., 2008, 2011a) allowed the determination of ET steps that occur in a hierarchically ordered time scale from nanoseconds to several seconds. Our study demonstrates that our SFITFY data is consistent with the concept of the reduction of P680(+) by YZ in both leaves and algae (studied on spinach leaves and cells of Chlorella pyrenoidosa Chick). The multiphasic P680(+) reduction kinetics by YZ in PS II core complexes with high oxygen evolution capacity was seen in both algae and leaves. Model simulation to fit SFITFY curves for dark adapted species used here gives the rate constants to verify nanosecond kinetic stages of P680(+) reduction by YZ in the redox state S1 of the water oxidizing complex (WOC) shown in Kühn et al. (2004). Then a sequence of relaxation steps in the redox state S1, outlined by Renger (2012), occurs in both algae and leaves as a similar non-adiabatic ET reactions. Coupled PT is discussed briefly to understand a rearrangement of hydrogen bond protons in the protein matrix of the WOC (Umena et al., 2011). On the other hand, present studies showed a slower reoxidation of reduced QA by QB in algal cells as compared with that in a leaf that might be regarded as a consequence of differences of spatial domains at the QB-site in leaves compared to algae. Our comparative study helped to correlate theory with experimental data for molecular photosynthetic mechanisms in thylakoid membranes.

  18. Toxicity of fluorotelomer carboxylic acids to the algae Pseudokirchneriella subcapitata and Chlorella vulgaris, and the amphipod Hyalella azteca.

    PubMed

    Mitchell, Rebecca J; Myers, Anne L; Mabury, Scott A; Solomon, Keith R; Sibley, Paul K

    2011-11-01

    Perfluorinated acids (PFAs) have elicited significant global regulatory and scientific concern due to their persistence and global pervasiveness. A source of PFAs in the environment is through degradation of fluorotelomer carboxylic acids (FTCAs) but little is known about the toxicity of these degradation products. Previous work found that FTCAs were two to three orders of magnitude more toxic to some freshwater invertebrates than their PFA counterparts and exhibited comparable chain-length-toxicity relationships. In this study, we investigated the toxicity of the 6:2, 8:2, and 10:2 saturated (FTsCA) and unsaturated (FTuCA) fluorotelomer carboxylic acids to two species of freshwater algae, Chlorella vulgaris and Pseudokirchneriella subcapitata, and the amphipod, Hyalella azteca. C. vulgaris was generally the most sensitive species, with EC₅₀s of 26.2, 31.8, 11.1, and 4.2 mg/L for the 6:2 FTsCA, 6:2 FTuCA, 8:2 FTuCA, and 10:2 FTsCA, respectively. H. azteca was most sensitive to the 8:2 FTsCA and 10:2 FTuCA, with LC₅₀s of 5.1 and 3.7 mg/L. The toxicity of the FTCAs generally increased with increasing carbon chain length, and with saturation for most of the species tested, with the exception of P. subcapitata, which did not exhibit any trend. These observations agree with chain-length-toxicity relationships previously reported for the PFCAs and support the greater toxicity of the FTCAs compared to PFCAs. However, the toxicity values are approximately 1000-fold above those detected in the environment indicating negligible risk to aquatic invertebrates.

  19. Conversion of membrane lipid acyl groups to triacylglycerol and formation of lipid bodies upon nitrogen starvation in biofuel green algae Chlorella UTEX29.

    PubMed

    Goncalves, Elton C; Johnson, Jodie V; Rathinasabapathi, Bala

    2013-11-01

    Algal lipids are ideal biofuel sources. Our objective was to determine the contributors to triacylglycerol (TAG) accumulation and lipid body formation in Chlorella UTEX29 under nitrogen (N) deprivation. A fivefold increase in intracellular lipids following N starvation for 24 h confirmed the oleaginous characteristics of UTEX29. Ultrastructural studies revealed increased number of lipid bodies and decreased starch granules in N-starved cells compared to N-replete cells. Lipid bodies were observed as early as 3 h after N removal and plastids collapsed after 48 h of stress. Moreover, the identification of intracellular pyrenoids and differences in the expected nutritional requirements for Chlorella protothecoides (as UTEX29 is currently classified) led us to conduct a phylogenetic study using 18S and actin cDNA sequences. This indicated UTEX29 to be more phylogenetically related to Chlorella vulgaris. To investigate the fate of different lipids after N starvation, radiolabeling using ¹⁴C-acetate was used. A significant decrease in ¹⁴C-galactolipids and phospholipids matched the increase in ¹⁴C-TAG starting at 3 h of N starvation, consistent with acyl groups from structural lipids as sources for TAG under N starvation. These results have important implications for the identification of key steps controlling oil accumulation in N-starved biofuel algae and demonstrate membrane recycling during lipid body formation.

  20. Ferric and cupric reductase activities by iron-limited cells of the green alga Chlorella kessleri: quantification via oxygen electrode.

    PubMed

    Weger, Harold G; Walker, Crystal N; Fink, Michael B

    2007-10-01

    The colorimetric Fe2+ indicators bathophenanthroline disulfonic acid (BPDS) and 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine (FZ) are routinely used to assay for plasma membrane ferric reductase activity in iron-limited algal cells and also in roots from iron-limited plants. Ferric reductase assays using these colorimetric indicators must take into account the fact that Fe3+ chelators (e.g. ethylenediaminetetraacetic acid) can also in general bind Fe2+ and may therefore compete with the colorimetric Fe2+ indicators, leading to the potential for underestimation of the ferric reduction rate. Conversely, the presence of BPDS or FZ may also facilitate the reduction of Fe3+ chelates, potentially leading to overestimation of ferric reduction rates. Last, both BPDS and FZ have non-negligible affinities for Fe3+ in addition to their well-known affinities for Fe2+; this leads to potential difficulties in ascertaining whether free and/or chelated Fe3+ are potential substrates for the ferric reductase. Similar issues arise when assaying for cupric reductase activity using the colorimetric Cu+ indicator bathocuproinedisulfonic acid (BCDS). In this paper, we describe an oxygen-electrode-based assay (conducted in darkness) for both ferric and cupric reductase activities that does not use colorimetric indicators. Using this assay system, we show that the plasma membrane metal reductase activity of iron-limited cells of the green alga Chlorella kessleri reduced complexed Fe3+ (i.e. Fe3+ chelates) but did not reduce free (non-chelated) Fe3+, and also reduced free Cu2+ to Cu+, but did not reduce Cu2+ that was part of Cu2+ chelates. We suggest that the potential for reduction of free Fe3+ cannot be adequately assayed using colorimetric assays. As well, the BPDS-based assay system consistently yielded similar estimates of ferric reductase activity compared with the O2-electrode-based assays at relatively low Fe3+ concentration, but higher estimates at higher Fe3

  1. Efficiency assessment and pH effect in removing nitrogen and phosphorus by algae-bacteria combined system of Chlorella vulgaris and Bacillus licheniformis.

    PubMed

    Liang, Zhijie; Liu, Yan; Ge, Fei; Xu, Yin; Tao, Nengguo; Peng, Fang; Wong, Minghung

    2013-08-01

    To achieve better removal of NH4(+) and TP in wastewater, a new algae-bacteria combined system of Chlorella vulgaris and Bacillus licheniformis was investigated in a 6-d experiment. The results showed that 78% of NH4(+) could be removed in the combined system, while 29% in single algae system and only 1% in single bacteria system. Approximately 92% of TP was removed in the combined system, compared with 55% and 78% in single algae and bacteria system, respectively. B. licheniformis was proven to be a growth-promoting bacterium for C. vulgaris by comparing Chl a concentrations in the single and combined systems. In the removal process, pH of the combined system was observed to reduce significantly from 7.0 to 3.5. Whereas with pH regulated to 7.0, higher removal efficiencies of NH4(+) (86%) and TP (93%) were achieved along with the recovery of algal cells and the increase of Chl a. These results suggest that nutrients in wastewater can be removed efficiently by the algae-bacteria combined system and pH control is crucial in the process.

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

    PubMed

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

    2015-08-31

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

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

    PubMed Central

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

    2015-01-01

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

  4. Biochemical composition of green alga Chlorella minutissima in mixotrophic cultures under the effect of different carbon sources.

    PubMed

    Gautam, Kshipra; Pareek, Ashwani; Sharma, Durlubh Kumar

    2013-11-01

    Mixotrophic growth of Chlorella minutissima with carbon supplements such as glucose, glycerol, succinate, molasses and press mud resulted in maximum biomass accumulation in glucose supplemented culture. Lipid content was maximum with molasses followed by press mud, fatty acid compositions of which also were best suited for biodiesel production.

  5. GAS EXCHANGE OF ALGAE. I. EFFECTS OF TIME, LIGHT INTENSITY, AND SPECTRAL-ENERGY DISTRIBUTION ON THE PHOTOSYNTHETIC QUOTIENT OF CHLORELLA PYRENOIDOSA.

    PubMed

    AMMANN, E C; LYNCH, V H

    1965-07-01

    Continuously growing cultures of Chlorella pyrenoidosa Starr 252, operating at constant density and under constant environmental conditions, produced uniform photosynthetic quotient (PQ = CO(2)/O(2)) and O(2) values during 6 months of observations. The PQ for the entire study was 0.90 +/- 0.024. The PQ remained constant over a threefold light-intensity change and a threefold change in O(2) production (0.90 +/- 0.019). At low light intensities, when the rate of respiration approached the rate of photosynthesis, the PQ became extremely variable. Six lamps of widely different spectral-energy distribution produced no significant change in the PQ (0.90 +/- 0.025). Oxygen production was directly related to the number of quanta available, irrespective of spectral-energy distribution. Such dependability in producing uniform PQ and O(2) values warrants a consideration of algae to maintain a constant gas environment for submarine or spaceship use.

  6. Chlorella: 125 years of the green survivalist.

    PubMed

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

    2015-02-01

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

  7. The Effect of Copper and Selenium Nanocarboxylates on Biomass Accumulation and Photosynthetic Energy Transduction Efficiency of the Green Algae Chlorella Vulgaris

    NASA Astrophysics Data System (ADS)

    Mykhaylenko, Natalia F.; Zolotareva, Elena K.

    2017-02-01

    Nanoaquachelates, the nanoparticles with the molecules of water and/or carboxylic acids as ligands, are used in many fields of biotechnology. Ultra-pure nanocarboxylates of microelements are the materials of spatial perspective. In the present work, the effects of copper and selenium nanoaquachelates carboxylated with citric acid on biomass accumulation of the green algae Chlorella vulgaris were examined. Besides, the efficiency of the reactions of the light stage of photosynthesis was estimated by measuring chlorophyll a fluorescence. The addition of 0.67-4 mg L-1 of Cu nanocarboxylates resulted in the increase in Chlorella biomass by ca. 20%; however, their concentrations ranging from 20 to 40 mg L-1 strongly inhibited algal growth after the 12th day of cultivation. Se nanocarboxylates at 0.4-4 mg L-1 concentrations also stimulated the growth of C. vulgaris, and the increase in biomass came up to 40-45%. The addition of Se nanocarboxylates at smaller concentrations (0.07 or 0.2 mg L-1) at first caused the retardation of culture growth, but that effect disappeared after 18-24 days of cultivation. The addition of 2-4 mg L-1 of Cu nanocarboxylates or 0.4-4 mg L-1 of Se nanocarboxylates caused the evident initial increase in such chlorophyll a fluorescence parameters as maximal quantum yield of photosystem II photochemistry ( F v/ F m) and the quantum yield of photosystem II photochemistry in the light-adapted state ( F v'/ F m'). Photochemical fluorescence quenching coefficients declined after 24 days of growth with Cu nanocarboxylates, but they increased after 6 days of the addition of 2 or 4 mg L-1 Se nanocarboxylates. Those alterations affected the overall quantum yield of the photosynthetic electron transport in photosystem II.

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

    PubMed Central

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

    1996-01-01

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

  9. Algae.

    PubMed

    Raven, John A; Giordano, Mario

    2014-07-07

    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.

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

    PubMed Central

    Avidan, Omri; Pick, Uri

    2015-01-01

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

  11. Air-drying of cells, the novel conditions for stimulated synthesis of triacylglycerol in a Green Alga, Chlorella kessleri.

    PubMed

    Shiratake, Takuma; Sato, Atsushi; Minoda, Ayumi; Tsuzuki, Mikio; Sato, Norihiro

    2013-01-01

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

  12. Size and structure of Chlorella zofingiensis /FeCl 3 flocs in a shear flow: Algae Floc Structure

    SciTech Connect

    Wyatt, Nicholas B.; O'Hern, Timothy J.; Shelden, Bion; Hughes, Lindsey G.; Mondy, Lisa A.

    2013-07-26

    Flocculation is a promising method to overcome the economic hurdle to separation of algae from its growth medium in large scale operations. But, understanding of the floc structure and the effects of shear on the floc structure are crucial to the large scale implementation of this technique. The floc structure is important because it determines, in large part, the density and settling behavior of the algae. Freshwater algae floc size distributions and fractal dimensions are presented as a function of applied shear rate in a Couette cell using ferric chloride as a flocculant. Comparisons are made with measurements made for a polystyrene microparticle model system taken here as well as reported literature results. The algae floc size distributions are found to be self-preserving with respect to shear rate, consistent with literature data for polystyrene. Moreover, three fractal dimensions are calculated which quantitatively characterize the complexity of the floc structure. Low shear rates result in large, relatively dense packed flocs which elongate and fracture as the shear rate is increased. Our results presented here provide crucial information for economically implementing flocculation as a large scale algae harvesting strategy.

  13. Substitution of stable isotopes in Chlorella

    NASA Technical Reports Server (NTRS)

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

    1969-01-01

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

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

    SciTech Connect

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

    1985-01-01

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

  15. Chlorella viruses isolated in China

    SciTech Connect

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

    1988-09-01

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

  16. Multi-objective optimization of media nutrients for enhanced production of algae biomass and fatty acid biosynthesis from Chlorella pyrenoidosa NCIM 2738.

    PubMed

    Kanaga, Kamaraj; Pandey, Ashutosh; Kumar, Sanjay; Geetanjali

    2016-01-01

    This study aimed to optimize significant medium nutrient parameters for maximization of algal lipid and biomass production by using multi objective optimization strategy. Nutrients (nitrate, phosphate and carbohydrate) were investigated to improve the lipid accumulation, biomass production and carbohydrate consumption individually and cumulative manner using a central composite design for the Chlorella pyrenoidosa NCIM 2738 cultivation. Maximum lipid, algal biomass and carbohydrate utilization for individual response optimization were found 34.8% (w/w), 1464.3mgL(-1) and 93.4%, respectively at different optimum level of selected parameters. Whereas, maximum lipid accumulation, biomass production and glucose consumption values in multi-response optimization were observed 28.9%, 1271.2mgL(-1) and 89.2%, respectively at optimum level of 16.8mM NaNO3, 300.9μM K2HPO4 and 2.6% (w/v) glucose. The overall enhancements in lipid productivities by single and multi-response optimization in comparison with control medium conditions were found 2.35 and 2.90-fold with productivity level of 24.8 and 30.6mgL(-1)day(-1), respectively.

  17. Potential lipid accumulation and growth characteristic of the green alga Chlorella with combination cultivation mode of nitrogen (N) and phosphorus (P).

    PubMed

    Li, Yuqin; Han, Fangxin; Xu, Hua; Mu, Jinxiu; Chen, Di; Feng, Bo; Zeng, Hongyan

    2014-12-01

    This study aimed to evaluate the potential lipid accumulation of an oleaginous Chlorella protothecoides by combination cultivation mode of nitrogen (N) and phosphorus (P). Under co-deficiency of N and P, the largest lipid content (55.8%) was accomplished in C. protothecoides, which was higher than either sole P-deficiency (32.77%) or N-deficiency (52.5%), or co-repletion of N and P (control) (22.17%). However, the highest lipid productivity (224.14mg/L/day) with combination mode of N-deficiency and P-repletion represented 1.19-3.70-fold more than that of control, P-deficiency/limitation, and co-deficiency of N and P, respectively. This indicating N-deficiency plus P-repletion was a promising lipid trigger to motivate lipid accumulation in C. protothecoides cells. Further, difference gel electrophoresis (DIGE)-based proteomics was employed to reveal the molecular pathways associated with lipid biosynthesis. These results provide the foundation to develop engineering strategies targeting lipid productivity for industrial production of microalgae-based biodiesel.

  18. Management of winter weeds affects Frankliniella fusca (Thysanoptera: Thripidae) dispersal.

    PubMed

    Beaudoin, A L P; Kennedy, G G

    2012-04-01

    Frankliniella fusca (Hinds) naturally disperses from winter weeds to crops in spring, causing direct and indirect damage. Field preparation before planting includes use of herbicides or cultivation to kill unwanted vegetation, which adversely affects F. fusca host plants and potentially influences F. fusca dispersal. Common chickweed, Stellaria media (L.), infested with F. fusca, was used as a model to study effects of timing and type of vegetation management on adult dispersal. Infested weeds were caged and F. fusca weekly dispersal was monitored using sticky traps. Weed management treatments performed at an early (14 April-11 May) or late (2 wk after early treatment) date consisted of glyphosate, paraquat, disking, hoeing, or untreated control. Late glyphosate and hoeing treatments resulted in cumulative dispersal statistically similar to or greater than from control plots. Compared with the control, significantly more F. fusca dispersed from the glyphosate and hoeing plots during the 3 wk after treatment. More thrips dispersed from the late paraquat treatment 1 wk post-application than from the control. Dispersal from the disked treatment and early paraquat treatment was similar to that of the control 1- to 3-wk post-treatment. Early treatments resulted in significantly smaller cumulative dispersal than the control in all but one instance. Late disking and paraquat treatments resulted in cumulative F. fusca captures that were statistically similar or less than that in the control. Winter weed management type and timing affect F. fusca dispersal magnitude and duration.

  19. Giant viruses infecting algae.

    PubMed

    Van Etten, J L; Meints, R H

    1999-01-01

    Paramecium bursaria chlorella virus (PBCV-1) is the prototype of a family of large, icosahedral, plaque-forming, double-stranded-DNA-containing viruses that replicate in certain unicellular, eukaryotic chlorella-like green algae. DNA sequence analysis of its 330, 742-bp genome leads to the prediction that this phycodnavirus has 376 protein-encoding genes and 10 transfer RNA genes. The predicted gene products of approximately 40% of these genes resemble proteins of known function. The chlorella viruses have other features that distinguish them from most viruses, in addition to their large genome size. These features include the following: (a) The viruses encode multiple DNA methyltransferases and DNA site-specific endonucleases; (b) PBCV-1 encodes at least part, if not the entire machinery to glycosylate its proteins; (c) PBCV-1 has at least two types of introns--a self-splicing intron in a transcription factor-like gene and a splicesomal processed type of intron in its DNA polymerase gene. Unlike the chlorella viruses, large double-stranded-DNA-containing viruses that infect marine, filamentous brown algae have a circular genome and a lysogenic phase in their life cycle.

  20. 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.

  1. Effect of aniline on Chlorella vulgaris

    SciTech Connect

    Amman, H.M.; Terry, b.

    1985-08-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. Inducible thermoalkalophilic polygalacturonate lyase from Thermomonospora fusca.

    PubMed Central

    Stutzenberger, F J

    1987-01-01

    A thermostable polygalacturonate lyase (PL; EC 4.2.2.2) was secreted by Thermomonospora fusca during stationary phase in pectin-mineral salts medium at 52 degrees C. Biosynthesis was induced by addition of pectic substances to cultures growing on glucose or cellulose but not cellobiose; the disaccharide repressed enzyme synthesis and triggered inactivation of enzyme previously secreted. The PL, purified to electrophoretic and serologic homogeneity, had a molecular size of 56 kilodaltons and an isoelectric point at pH 4.16. The amino acid composition closely resembled that of the major extracellular endoglucanases of the actinomycete. The enzyme had six cystine residues but no detectable sulfhydryl groups. It was inactivated by mild reducing agents and activated by oxygenation, indicating the necessity for disulfide bond maintenance. Temperature and pH optima for the PL reaction were 60 degrees C and 10.45, respectively. Calcium was essential for activity but not stability; calcium dependence curves were altered by low concentrations of toxic metals. The Km for pectin increased 30,000-fold as the percent esterification (methoxylation) of that substrate was increased from 0 to 60%. The size of the minimal susceptible site for PL attack on the pectin molecule was calculated as being equivalent to 10 unesterified residues, based on the correlation of Km values at various degrees of esterification with the percentage of cleavable bonds predicted by a random-number-generating computer program. Images PMID:3584069

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

    PubMed

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

    2014-06-01

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

  6. Glycolate Pathway in Algae 1

    PubMed Central

    Hess, J. L.; Tolbert, N. E.

    1967-01-01

    No glycolate oxidase activity could be detected by manometric, isotopic, or spectrophotometric techniques in cell extracts from 5 strains of algae grown in the light with CO2. However, NADH:glyoxylate reductase, phosphoglycolate phosphatase and isocitrate dehydrogenase were detected in the cell extracts. The serine formed by Chlorella or Chlamydomonas after 12 seconds of photosynthetic 14CO2 fixation contained 70 to 80% of its 14C in the carboxyl carbon. This distribution of label in serine was similar to that in phosphoglycerate from the same experiment. Thus, in algae serine is probably formed directly from phosphoglycerate. These results differ from those of higher plants which form uniformly labeled serine from glycolate in short time periods when phosphoglycerate is still carboxyl labeled. In glycolate formed by algae in 5 and 10 seconds of 14CO2 fixation, C2 was at least twice as radioactive as C1. A similar skewed labeling in C2 and C3 of 3-phosphoglycerate and serine suggests a common precursor for glycolate and 3-phosphoglycerate. Glycine formed by the algae, however, from the same experiments was uniformly labeled. Manganese deficient Chlorella incorporated only 2% of the total 14CO2 fixed in 10 minutes into glycolate, while in normal Chlorella 30% of the total 14C was found in glycolate. Manganese deficient Chlorella also accumulated more 14C in glycine and serine. Glycolate excretion by Chlorella was maximal in 10 mm bicarbonate and occurred only in the light, and was not influenced by the addition of glycolate. No time dependent uptake of significant amounts of either glycolate or phosphoglycolate was observed. When small amounts of glycolate-2-14C were fed to Chlorella or Scenedesmus, only 2 to 3% was metabolized after 30 to 60 minutes. The algae were not capable of significant glycolate metabolism as is the higher plant. The failure to detect glycolate oxidase, the low level glycolate-14C metabolism, and the formation of serine from phosphoglycerate

  7. Acute and chronic toxic effects of chloramphenicol on Scenedesmus obliquus and Chlorella pyrenoidosa.

    PubMed

    Zhang, Wei; Sun, Wenfang; An, Shuai; Xiong, Bang; Lin, Kuangfei; Cui, Xinhong; Guo, Meijin

    2013-08-01

    The acute and chronic toxicological effects of Chloramphenicol (CAP) on Scenedesmus obliquus and Chlorella pyrenoidosa are not well understood. The indoor experiments were carried to observe and analyze the CAP induced changes. Results of the observations have showed that CAP exposure could significantly inhibit the growth of Scenedesmus obliquus in almost all the treated groups, while Chlorella pyrenoidosa exhibited less sensitivity. Chlorophyll-a syntheses of Scenedesmus obliquus were all inhibited by CAP exposure, while Chlorella pyrenoidosa displayed obvious stimulation effect. Catalase (CAT) and Superoxide dismutase (SOD) activities of both algae were promoted in all the treatments. The experimental results indicated that the growth and Chlorophyll-a syntheses of Scenedesmus obliquus were more sensitive in response to CAP exposure than that of Chlorella pyrenoidosa. While for CAT and SOD activities, Chlorella pyrenoidosa showed more susceptible. This research provides a basic understanding of CAP toxicity to aquatic organisms.

  8. Short-chain aliphatic ester synthesis using Thermobifida fusca cutinase.

    PubMed

    Su, Lingqia; Hong, Ruoyu; Guo, Xiaojie; Wu, Jing; Xia, Yongmei

    2016-09-01

    Short-chain aliphatic esters are commonly used as fruit flavorings in the food industry. In this study, Thermobifida fusca (T. fusca) cutinase was used for the synthesis of aliphatic esters, and the maximum yield of ethyl caproate reached 99.2% at a cutinase concentration of 50U/ml, 40°C, and water content of 0.5%, representing the highest ester yield to date. The cutinase-catalyzed esterification displayed strong tolerance for water content (up to 8%) and acid concentration (up to 0.8M). At substrate concentrations ⩽0.8M, the ester yield remained above 80%. Moreover, ester yields of more than 98% and 95% were achieved for acids of C3-C8 and alcohols of C1-C6, respectively, indicating extensive chain length selectivity of the cutinase. These results demonstrate the superior ability of T. fusca cutinase to catalyze the synthesis of short-chain esters. This study provides the basis for industrial production of short-chain esters using T. fusca cutinase.

  9. Dispersed ozone flotation of Chlorella vulgaris.

    PubMed

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

    2010-12-01

    Flotation separation of Chlorella vulgaris, a species with excellent potential for CO(2) capture and lipid production, was studied using dispersed ozone gas. Pure oxygen aeration did not yield flotation. Conversely, applying ozone effectively separation algae from broth through flotation. The ozone dose applied for sufficient algal flotation is <0.05 mg/g biomass, much lower than those used in practical drinking waterworks (0.1-0.3 mg/g suspended solids). Main products, lipid C16:0, was effectively collected in the flotage phase. The algae removal rate, surface charge, and hydrophobicity of algal cells, and proteins and polysaccharides contents of algogenic organic matter (AOM) were determined. Certain quantities of proteins were present in the cultivated algal suspension, hence, minimal quantity of ozone was required to release intracellular proteins as surfactants to lead to effective flotation.

  10. Uptake of hydrophobic metal complexes by three freshwater algae: unexpected influence of pH.

    PubMed

    Boullemant, Amiel; Lavoie, Michel; Fortin, Claude; Campbell, Peter G C

    2009-05-01

    Cadmium forms neutral, lipophilic Cd(L)2(0) complexes with diethyldithiocarbamate (DDC) and with ethylxanthate (XANT). Uptake of these complexes bythree unicellularfreshwater green algae (Chlamydomonas reinhardtii, Chlorella fusca, and Pseudokirchneriella subcapitata) was determined at two pH values (7.0 and 5.5) and compared to uptake of the free, uncomplexed Cd2+ ion. Uptake of the lipophilic complexes over time, characterized by high initial uptake rates but tending toward a plateau after about 30 min, could be modeled successfully as the result of the following processes: first-order uptake from solution, partitioning of the accumulated Cd into two internal pools (labile and nonlabile), and first-order loss of Cd from the labile pool. At pH 7.0 initial uptake rates for both Cd(L)2(0) complexes were much higher than for Cd2+ alone (e.g., up to approximately 90 times higher for comparable dissolved Cd concentrations of approximately 0.4 nM). However, the initial uptake rates for the lipophilic complexes dropped dramatically when the pH was lowered from 7.0 to 5.5 (2- to 60-fold decrease, depending on the algal species and the nature of the neutral complex). Loss rates for the accumulated complexes also decreased atthe lower pH. The lipophilicity of the neutral complexes, as estimated from their octanol-water distribution coefficient (Dow), was not affected by the decrease in pH from 7.0 to 5.5. We thus conclude that the acidification of the external medium, i.e., the interaction of protons with the algal membrane, strongly affects algal membrane permeability.

  11. Influence of plant silicon in Busseola fusca (Lepidoptera: Noctuidae) larvae - Poaceae interactions.

    PubMed

    Juma, G; Ahuya, P O; Ong'amo, G; Le Ru, B; Magoma, G; Silvain, J-F; Calatayud, P-A

    2015-04-01

    The noctuid stem borer Busseola fusca is an important pest of maize and sorghum in Sub-Saharan Africa. The presence of this species occurred mostly on cultivated than on wild habitats. Busseola fusca is oligophagous having a narrow range of a wild grass species. This might be due, in part, to differences in silicon (Si) content in plant tissues between cultivated and wild grasses. In the present study, we have tested this hypothesis by studying the survival and the relative growth rate (RGR) expressed as daily weight gains of B. fusca larvae on maize and six wild host plants, mostly present in the natural habitat where B. fusca occurred, and correlated with their Si contents. Survival and RGR of B. fusca larvae were considerably higher on maize and wild sorghum than on the other grass species, and they were negatively related to plant Si content. This was corroborated with results on RGR from artificial diets amended with increasing levels of Si. In addition, if Si was added to maize growing substrate B. fusca larval growth was significantly reduced confirming the involvement of Si in B. fusca larvae - Poaceae interactions. The results provide insight into the possible mechanisms of oligophagy of B. fusca and provide a correlative support for a physical role of plant endogenous Si in impeding feeding of B. fusca larvae.

  12. Draft Genome Sequence of the Lignocellulose Decomposer Thermobifida fusca Strain TM51.

    PubMed

    Tóth, Akos; Barna, Terézia; Nagy, István; Horváth, Balázs; Nagy, István; Táncsics, András; Kriszt, Balázs; Baka, Erzsébet; Fekete, Csaba; Kukolya, József

    2013-07-11

    Here, we present the complete genome sequence of Thermobifida fusca strain TM51, which was isolated from the hot upper layer of a compost pile in Hungary. T. fusca TM51 is a thermotolerant, aerobic actinomycete with outstanding lignocellulose-decomposing activity.

  13. Research for Developing Renewable Biofuels from Algae

    SciTech Connect

    Black, Paul N.

    2012-12-15

    Task A. Expansion of knowledge related to lipid production and secretion in algae A.1 Lipid biosynthesis in target algal species; Systems biology approaches are being used in combination with recent advances in Chlorella and Chlamydomonas genomics to address lipid accumulation in response to defined nutrient regimes. The UNL Algal Group continues screening additional species of Chlorella and other naturally occurring algae for those with optimal triglyceride production; Of the strains examined by the DOE's Aquatic Species Program, green algae, several species of Chlorella represent the largest group from which oleaginous candidates have been identified; A.1.1. Lipid profiling; Neutral lipid accumulation is routinely monitored by Nile red and BODIPY staining using high throughput strategies to screen for naturally occurring algae that accumulate triglyceride. These strategies complement those using spectrofluorometry to quantify lipid accumulation; Neutral lipid accumulation is routinely monitored by high performance thin-layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) of lipid extracts in conjunction with; Carbon portioning experiments have been completed and the data currently are being analyzed and prepared for publication; Methods in the Black lab were developed to identify and quantify triacylglycerol (TAG), major membrane lipids [diacylglycerol trimethylhomoserine, phosphatidylethanolamine and chloroplast glycolipids], biosynthetic intermediates such as diacylglycerol, phosphatidic acid and lysophospholipids and different species of acyl-coenzyme A (acyl CoA).

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

    PubMed

    Laliberté, G; Hellebust, J A

    1989-11-01

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

  15. Oral focal epithelial hyperplasia in a howler monkey (Alouatta fusca).

    PubMed

    Sá, L R; DiLoreto, C; Leite, M C; Wakamatsu, A; Santos, R T; Catão-Dias, J L

    2000-09-01

    Oral focal epithelial hyperplasia is a rare and seldom reported disease in animals and humans induced by a papillomavirus. The present report is the first description of this disease in a Neotropical primate, a howler monkey (Alouatta fusca). The diagnosis was based on gross and microscopic findings. The generic papillomavirus antigen was identified by immunohistochemistry and was found not to be related to any human papillomavirus DNA tested by in situ hybridization. This virus is probably a specific papillomavirus of the howler monkey (HMPV).

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

    PubMed

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

  18. 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.

  19. Study of ecotoxicity of silver nanoparticles using algae

    NASA Astrophysics Data System (ADS)

    Kustov, L. M.; Abramenko, N. B.

    2016-11-01

    Silver nanoparticles have been prepared and tested for their ecotoxicity using Chlorella vulgaris Beijer. algae as a hydrobiotic test organism and a photometric method of control. The toxicity was supposed to originate from Ag+ ions released into the aqueous solution. Also, the toxicity of the stabilizing agent was found to be comparable to that of silver nanoparticles.

  20. Increase in Chlorella strains calorific values when grown in low nitrogen medium.

    PubMed

    Illman; Scragg; Shales

    2000-11-01

    The calorific value of five strains of Chlorella grown in Watanabe and low-nitrogen medium was determined. The algae were grown in small (2L) stirred tank bioreactors and the best growth was obtained with Chlorella vulgaris with a growth rate of 0.99 d(-1) and the highest calorific value (29 KJ/g) was obtained with C. emersonii. The cellular components were assayed at the end of the growth period and the calorific value appears to be linked to the lipid content rather than any other component.

  1. Chlorella-derived multicomponent supplementation increases aerobic endurance capacity in young individuals

    PubMed Central

    Umemoto, Sachiro; Otsuki, Takeshi

    2014-01-01

    Chlorella, a unicellular green alga, contains a variety of nutrients including amino acids, carbohydrates, vitamins, and minerals. A previous animal study found that maximal swimming time in mice increased after 14 days on a diet including Chlorella powder compared to no change in swimming performance on a normal diet. However, it is currently unknown whether Chlorella-derived multicomponent supplementation increases aerobic endurance capacity in humans. We investigated the effects of Chlorella-derived supplementation on peak oxygen uptake during incremental maximal cycling in young individuals using a double-blinded, placebo-controlled, crossover study design. Seven men and three women (mean age, 21.3 year) were allocated to placebo or Chlorella tablets (15 tablets × twice per day) for 4 weeks, with at least a 6-week washout period between trials, in a randomized order. Peak oxygen uptake significantly increased after Chlorella supplementation (before vs after, 37.9 ± 1.9 vs 41.4 ± 1.9 ml/kg/min, p = 0.003), but not with placebo (39.4 ± 2.2 vs 40.1 ± 2.1 ml/kg/min, p = 0.38). The change in peak oxygen uptake over the 4-week trial was significantly greater in the Chlorella trial than in the placebo trial (3.5 ± 0.9 vs 0.7 ± 0.8 ml/kg/min, p = 0.03). These results suggest that Chlorella-derived multicomponent supplementation increases aerobic endurance capacity in young individuals. PMID:25320462

  2. Anti-Helicobacter pylori xanthones of Garcinia fusca.

    PubMed

    Nontakham, Jannarin; Charoenram, Napaporn; Upamai, Wanchalerm; Taweechotipatr, Malai; Suksamrarn, Sunit

    2014-08-01

    A new geranylated xanthone derivative, fuscaxanthone I (1), along with nine xanthones (2-9 and 11), a biphenyl (10) and three biflavonoids (12-14) were isolated from the roots of Garcinia fusca Pierre. Compounds 8, 10 and 11-14 were reported from this plant species for the first time. Their structures were elucidated by spectroscopic analyses, including 1D- and 2D-NMR and MS. The isolated compounds were evaluated for antibacterial activity against Helicobacter pylori. Cowaxanthone (5) and fukugiside (14) exhibited stronger inhibitory activity against H. pylori DMST reference strain at MICs 4.6 and 10.8 μM, respectively, than that of the control metronidazole. Isojacareubin (8) displayed the most potent activity against H. pylori HP40 clinical isolate with MIC 23.9 μM, which was approximately two times greater than that of the standard drug amoxicillin.

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

    PubMed

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

    2016-05-20

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

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

    SciTech Connect

    Van Etten, J.L.

    1984-01-01

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

  5. Lipid production by a CO₂-tolerant green microalga, Chlorella sp. MRA-1.

    PubMed

    Zheng, Yanlin; Yuan, Cheng; Liu, Junhan; Hu, Guangrong; Li, Fuli

    2014-05-01

    Since CO2 concentrations in industrial flue gases are usually 10%-20%, one of the prerequisites for efficient CO2 removal by algae is the level of tolerance of microalgal species to exposure to high concentrations of CO2. A newly isolated microalgal strain, Chlorella sp. MRA-1, could retain growth with high concentrations of CO2 up to 15%. The highest lipid productivity for Chlorella sp. MRA-1 was 0.118 g/l/day with a 5% CO2 concentration. Octadecenoic acid and hexadecanoic acid, the main components of biodiesel, accounted for 70% of the total fatty acids. A lipid content of 52% of dry cell weight was achieved with limited amounts of nitrogen. Chlorella sp. MRA-1 seems to be an ideal candidate for biodiesel production when cultured with high concentrations of CO2.

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

    SciTech Connect

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

    1995-07-01

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

  7. 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

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

    PubMed

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

    2009-07-01

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

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

    PubMed

    Jafari, Yaser; Sabahi, Hossein; Rahaie, Mahdi

    2016-11-15

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

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

    PubMed

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

    2007-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

  12. 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)

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

    PubMed

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

    2015-04-01

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

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

    SciTech Connect

    Joung, J.J.; Akin, C.

    1983-01-01

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

  15. Investigating the coenzyme specificity of phenylacetone monooxygenase from Thermobifida fusca.

    PubMed

    Dudek, Hanna M; Torres Pazmiño, Daniel E; Rodríguez, Cristina; de Gonzalo, Gonzalo; Gotor, Vicente; Fraaije, Marco W

    2010-11-01

    Type I Baeyer-Villiger monooxygenases (BVMOs) strongly prefer NADPH over NADH as an electron donor. In order to elucidate the molecular basis for this coenzyme specificity, we have performed a site-directed mutagenesis study on phenylacetone monooxygenase (PAMO) from Thermobifida fusca. Using sequence alignments of type I BVMOs and crystal structures of PAMO and cyclohexanone monooxygenase in complex with NADP(+), we identified four residues that could interact with the 2'-phosphate moiety of NADPH in PAMO. The mutagenesis study revealed that the conserved R217 is essential for binding the adenine moiety of the nicotinamide coenzyme while it also contributes to the recognition of the 2'-phosphate moiety of NADPH. The substitution of T218 did not have a strong effect on the coenzyme specificity. The H220N and H220Q mutants exhibited a ~3-fold improvement in the catalytic efficiency with NADH while the catalytic efficiency with NADPH was hardly affected. Mutating K336 did not increase the activity of PAMO with NADH, but it had a significant and beneficial effect on the enantioselectivity of Baeyer-Villiger oxidations and sulfoxidations. In conclusion, our results indicate that the function of NADPH in catalysis cannot be easily replaced by NADH. This finding is in line with the complex catalytic mechanism and the vital role of the coenzyme in BVMOs.

  16. Investigating the coenzyme specificity of phenylacetone monooxygenase from Thermobifida fusca

    PubMed Central

    Dudek, Hanna M.; Torres Pazmiño, Daniel E.; Rodríguez, Cristina; de Gonzalo, Gonzalo; Gotor, Vicente

    2010-01-01

    Type I Baeyer–Villiger monooxygenases (BVMOs) strongly prefer NADPH over NADH as an electron donor. In order to elucidate the molecular basis for this coenzyme specificity, we have performed a site-directed mutagenesis study on phenylacetone monooxygenase (PAMO) from Thermobifida fusca. Using sequence alignments of type I BVMOs and crystal structures of PAMO and cyclohexanone monooxygenase in complex with NADP+, we identified four residues that could interact with the 2′-phosphate moiety of NADPH in PAMO. The mutagenesis study revealed that the conserved R217 is essential for binding the adenine moiety of the nicotinamide coenzyme while it also contributes to the recognition of the 2′-phosphate moiety of NADPH. The substitution of T218 did not have a strong effect on the coenzyme specificity. The H220N and H220Q mutants exhibited a ~3-fold improvement in the catalytic efficiency with NADH while the catalytic efficiency with NADPH was hardly affected. Mutating K336 did not increase the activity of PAMO with NADH, but it had a significant and beneficial effect on the enantioselectivity of Baeyer–Villiger oxidations and sulfoxidations. In conclusion, our results indicate that the function of NADPH in catalysis cannot be easily replaced by NADH. This finding is in line with the complex catalytic mechanism and the vital role of the coenzyme in BVMOs. PMID:20703875

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

    NASA Astrophysics Data System (ADS)

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

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

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

    PubMed

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

    1989-01-01

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

  19. Effect of light intensity on algal biomass accumulation and biodiesel production for mixotrophic strains Chlorella kessleri and Chlorella protothecoide cultivated in highly concentrated municipal wastewater.

    PubMed

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

    2012-09-01

    In this research, the effect of light intensity on biomass accumulation, wastewater nutrient removal through algae cultivation, and biodiesel productivity was investigated with algae species Chlorella kessleri and Chlorella protothecoide. The light intensities studied were 0, 15, 30, 60, 120, and 200 µmol m(-2) s(-1). The results showed that light intensity had profound impact on tested responses for both strains, and the dependence of these responses on light intensity varied with different algae strains. For C. kessleri, the optimum light intensity was 120 µmol m(-2) S(-1) for all responses except for COD removal. For C. protothecoide, the optimum light intensity was 30 µmol m(-2) S(-1). The major components of the biodiesel produced from algae biomass were 16-C and 18-C FAME, and the highest biodiesel contents were 24.19% and 19.48% of dried biomass for C. kessleri and C. protothecoide, respectively. Both species were capable of wastewater nutrients removal under all lighting conditions with high removal efficiencies.

  20. Gas Exchange of Algae

    PubMed Central

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

    1965-01-01

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

  1. 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.

  2. Proteomics-based metabolic modeling and characterization of the cellulolytic bacterium Thermobifida fusca

    PubMed Central

    2014-01-01

    Background Thermobifida fusca is a cellulolytic bacterium with potential to be used as a platform organism for sustainable industrial production of biofuels, pharmaceutical ingredients and other bioprocesses due to its capability of potential to convert plant biomass to value-added chemicals. To best develop T. fusca as a bioprocess organism, it is important to understand its native cellular processes. In the current study, we characterize the metabolic network of T. fusca through reconstruction of a genome-scale metabolic model and proteomics data. The overall goal of this study was to use multiple metabolic models generated by different methods and comparison to experimental data to gain a high-confidence understanding of the T. fusca metabolic network. Results We report the generation of three versions of a metabolic model of Thermobifida fusca sp. XY developed using three different approaches (automated, semi-automated, and proteomics-derived). The model closest to in vivo growth was the proteomics-derived model that consists of 975 reactions involving 1382 metabolites and account for 316 EC numbers (296 genes). The model was optimized for biomass production with the optimal flux of 0.48 doublings per hour when grown on cellobiose with a substrate uptake rate of 0.25 mmole/h. In vivo activity of the DXP pathway for terpenoid biosynthesis was also confirmed using real-time PCR. Conclusions iTfu296 provides a platform to understand and explore the metabolic capabilities of the actinomycete T. fusca for the potential use in bioprocess industries for the production of biofuel and pharmaceutical ingredients. By comparing different model reconstruction methods, the use of high-throughput proteomics data as a starting point proved to be the most accurate to in vivo growth. PMID:25115351

  3. Kinetic mechanism of phenylacetone monooxygenase from Thermobifida fusca.

    PubMed

    Torres Pazmiño, Daniel E; Baas, Bert-Jan; Janssen, Dick B; Fraaije, Marco W

    2008-04-01

    Phenylacetone monooxygenase (PAMO) from Thermobifida fusca is a FAD-containing Baeyer-Villiger monooxygenase (BVMO). To elucidate the mechanism of conversion of phenylacetone by PAMO, we have performed a detailed steady-state and pre-steady-state kinetic analysis. In the catalytic cycle ( k cat = 3.1 s (-1)), rapid binding of NADPH ( K d = 0.7 microM) is followed by a transfer of the 4( R)-hydride from NADPH to the FAD cofactor ( k red = 12 s (-1)). The reduced PAMO is rapidly oxygenated by molecular oxygen ( k ox = 870 mM (-1) s (-1)), yielding a C4a-peroxyflavin. The peroxyflavin enzyme intermediate reacts with phenylacetone to form benzylacetate ( k 1 = 73 s (-1)). This latter kinetic event leads to an enzyme intermediate which we could not unequivocally assign and may represent a Criegee intermediate or a C4a-hydroxyflavin form. The relatively slow decay (4.1 s (-1)) of this intermediate yields fully reoxidized PAMO and limits the turnover rate. NADP (+) release is relatively fast and represents the final step of the catalytic cycle. This study shows that kinetic behavior of PAMO is significantly different when compared with that of sequence-related monooxygenases, e.g., cyclohexanone monooxygenase and liver microsomal flavin-containing monooxygenase. Inspection of the crystal structure of PAMO has revealed that residue R337, which is conserved in other BVMOs, is positioned close to the flavin cofactor. The analyzed R337A and R337K mutant enzymes were still able to form and stabilize the C4a-peroxyflavin intermediate. The mutants were unable to convert either phenylacetone or benzyl methyl sulfide. This demonstrates that R337 is crucially involved in assisting PAMO-mediated Baeyer-Villiger and sulfoxidation reactions.

  4. Hot water extract of Chlorella vulgaris induced DNA damage and apoptosis

    PubMed Central

    Yusof, Yasmin Anum Mohd; Md. Saad, Suhana; Makpol, Suzana; Shamaan, Nor Aripin; Ngah, Wan Zurinah Wan

    2010-01-01

    OBJECTIVES: The aim of this study was to determine the antiproliferative and apoptotic effects of hot water extracts of Chlorella vulgaris on hepatoma cell line HepG2. INTRODUCTION: The search for food and spices that can induce apoptosis in cancer cells has been a major study interest in the last decade. Chlorella vulgaris, a unicellular green algae, has been reported to have antioxidant and anti‐cancer properties. However, its chemopreventive effects in inhibiting the growth of cancer cells have not been studied in great detail. METHODS: HepG2 liver cancer cells and WRL68 normal liver cells were treated with various concentrations (0‐4 mg/ml) of hot water extract of C. vulgaris after 24 hours incubation. Apoptosis rate was evaluated by TUNEL assay while DNA damage was assessed by Comet assay. Apoptosis proteins were evaluated by Western blot analysis. RESULTS: Chlorella vulgaris decreased the number of viable HepG2 cells in a dose dependent manner (p < 0.05), with an IC50 of 1.6 mg/ml. DNA damage as measured by Comet assay was increased in HepG2 cells at all concentrations of Chlorella vulgaris tested. Evaluation of apoptosis by TUNEL assay showed that Chlorella vulgaris induced a higher apoptotic rate (70%) in HepG2 cells compared to normal liver cells, WRL68 (15%). Western blot analysis showed increased expression of pro‐ apoptotic proteins P53, Bax and caspase‐3 in the HepG2 cells compared to normal liver cells WRL68, and decreased expression of the anti‐apoptotic protein Bcl‐2. CONCLUSIONS: Chlorella vulgaris may have anti‐cancer effects by inducing apoptosis signaling cascades via an increased expression of P53, Bax and caspase‐3 proteins and through a reduction of Bcl‐2 protein, which subsequently lead to increased DNA damage and apoptosis. PMID:21340229

  5. Algae Resources

    SciTech Connect

    2016-06-01

    Algae are highly efficient at producing biomass, and they can be found all over the planet. Many use sunlight and nutrients to create biomass, which contain key components—including lipids, proteins, and carbohydrates— that can be converted and upgraded to a variety of biofuels and products. A functional algal biofuels production system requires resources such as suitable land and climate, sustainable management of water resources, a supplemental carbon dioxide (CO2) supply, and other nutrients (e.g., nitrogen and phosphorus). Algae can be an attractive feedstock for many locations in the United States because their diversity allows for highpotential biomass yields in a variety of climates and environments. Depending on the strain, algae can grow by using fresh, saline, or brackish water from surface water sources, groundwater, or seawater. Additionally, they can grow in water from second-use sources such as treated industrial wastewater; municipal, agricultural, or aquaculture wastewater; or produced water generated from oil and gas drilling operations.

  6. Isolation, characterization, and complete genome analysis of P1312, a thermostable bacteriophage that infects Thermobifida fusca

    PubMed Central

    Cheepudom, Jatuporn; Lee, Cheng-Cheng; Cai, Bingfu; Meng, Menghsiao

    2015-01-01

    Thermobifida fusca is a moderately thermophilic and cellulolytic actinobacterium. It is of particular interest due to its ability to not only produce a variety of biotechnologically relevant enzymes but also serve as an alternative host for metabolic engineering for the production of valuable chemicals from lignocellulosic agricultural wastes. No bacteriophage that infects T. fusca has been reported, despite its potential impacts on the utilization of T. fusca. In this study, an extremely thermostable bacteriophage P1312 that infects T. fusca was isolated from manure compost. Electron microscopy showed that P1312 has an icosahedral head and a long flexible non-contractile tail, a characteristic of the family Siphoviridae. P1312 has a double-stranded DNA genome of 60,284 bp with 93 potential ORFs. Thirty-one ORFs encode proteins having putative biological functions. The genes involved in phage particle formation cluster together in a region of approximately 16 kb, followed by a segment containing genes presumably for DNA degradation/modification and cell wall disruption. The genes required for DNA replication and transcriptional control are dispersed within the rest of the genome. Phylogenetic analysis of large terminase subunit suggests that P1312 is a headful packaging phage containing a chromosome with circularly permuted direct terminal repeats. PMID:26441893

  7. Gohieria fusca (Acari: Astigmata) found in the filter dusts of air conditioners in China.

    PubMed

    Li, Chaopin; Zhan, Xiaodong; Zhao, Jinhong; Wei, Guo

    2014-10-06

    Objetivo: La Gohieria fusca (Oudemans, 1902) se reproduce en la harina de trigo, arroz, maíz, piensos, salvado de trigo y los medicamentos a base de hierbas, además de en otros productos almacenados; este ácaro puede tener una reactividad cruzada de leve a moderada con alérgenos de los ácaros del polvo domésticos, una importante fuente de alérgenos de interior asociada al asma y otras afecciones alérgicas. Los sistemas de aire acondicionado son indispensables en edificios públicos y civiles, y las pantallas de estos aparatos son los lugares donde más se acumula el polvo. Se realizó este estudio con el fin de investigar si la Gohieria fusca puede reproducirse en las pantallas de los acondicionadores de aire instalados en espacios públicos o viviendas en la ciudad de Wuhu, provincia de Anhui, China. Métodos: Se recogieron 430 muestras de polvo de los filtros de los sistemas de aire acondicionado en la cafeterías de centros educativos, mercados, hoteles y edificios civiles entre junio y septiembre de 2013, y se aisló la Gohieria fusca de dichas muestras. Resultados: Los resultados indicaron que la Gohieria fusca estaba presente en 98 de las 430 muestras (22,79%), y la tasa de reproducción fue significativa en los filtros del aire acondicionado de diferentes espacios (c2=18.294, P.

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

    PubMed

    Nancucheo, Ivan; Barrie Johnson, D

    2012-01-01

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

  9. Anaerobic co-digestion of microalgae Chlorella sp. and waste activated sludge.

    PubMed

    Wang, Meng; Sahu, Ashish K; Rusten, Bjørn; Park, Chul

    2013-08-01

    The study investigated the growth characteristics of environmental algal strain, Chlorella, in the modified Zarrouk medium and its anaerobic co-digestion with waste activated sludge (WAS). Analysis of extracellular polymeric substances (EPS) in algal culture and WAS indicated that Chlorella secreted more EPS into the surrounding liquid than formed floc-associated EPS as in activated sludge. Mesophilic anaerobic digestion of algae alone required extended digestion period to produce methane, with biogas yield at 262 mL/gVSfed after 45 days of digestion. When algae was co-digested with varying amounts of WAS, 59-96% in mass, not only biogas yield of microalgae improved but the gas phase was reached more quickly. The dewaterability of co-digestion products were also better than two controls digesting WAS or algae only. These results suggest that anaerobic co-digestion of algae and sludge improves the digestibility of microalgae and could also bring synergistic effects on the dewaterability of digested products for existing anaerobic digesters.

  10. Investigations on the feeding habits of the rocky-shore mite Hyadesia fusca (Acari: Astigmata: Hyadesiidae): diet range, food preference, food quality, and the implications for distribution patterns

    NASA Astrophysics Data System (ADS)

    Bücking, Jens

    1998-06-01

    Within the food web of estuarine and marine rocky shore ecosystems phytophagous mites of terrestrial and marine origin constitute an important part as grazers on algae and as a food source for certain arthropods, especially zoophagous mites. This investigation deals with the feeding biology of Hyadesia fusca taking as an example a population located on an artificial rocky shore of the middle Weser estuary in Northern Germany. The species is characterized by a broad diet range; in feeding experiments diatoms, lichens, detritus as well as blue, red and green algae were accepted. Even analyses of faecal pellets produced by field specimen suggest a non-specific feeding habit. However, the influence of certain diets on mortality, offspring number and rearing success showed that the food quality differs significantly. The most suitable food, the Ulvaceae Blidingia, was clearly preferred in a series of pairwise choice tests. These findings correlate with the vertical zonation of the field population i.e.: higher population densities in the vegetation zone dominated by Blidingia. It can be concluded that in addition to abiotic factors food supply could play an important role for distribution patterns of phytophagous mites.

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2010-01-01

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

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

    DOE PAGES

    Mansfeldt, Cresten B.; Richter, Lubna V.; Ahner, Beth A.; ...

    2016-02-03

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

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

    SciTech Connect

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

    2010-05-06

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

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

    PubMed Central

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

    2016-01-01

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

  16. Host-Parasite Biology of Thripinema fuscum (Tylenchida: Allantonematidae) and Frankliniella fusca (Thysanoptera: Thripidae)

    PubMed Central

    Sims, Kelly; Funderburk, Joe; Boucias, Drion

    2005-01-01

    Thripinema fuscum is a natural enemy of Frankliniella fusca in peanut. Laboratory experiments were conducted to determine the reproductive biology of T. fuscum as affected by gender and stage of development of the host and to determine the effects of parasitism on host longevity, fecundity, and mortality. The adult females of F. fusca were the most readily parasitized (P < 0.001) in the laboratory experiments followed by the second instars, the first instars, and the adult males. One generation of T. fuscum developed within the parasitized larvae and adults, with the males and females emerging only during the adult stage of the host. Parasitism did not cause mortality of the host. Parasitism affected male longevity (P < 0.001) but not female longevity. The adult female thrips that were parasitized as first or second instars did not lay eggs, and the adult females stopped laying eggs within 3 days of being parasitized. The female-to-male sex ratio of T. fuscum emerging from parasitized male and female F. fusca was 22 and 18 to 1, respectively. More T. fuscum emerged from female hosts than from male hosts (P < 0.001). More emerged from hosts parasitized as larvae compared with hosts parasitized as adults (P < 0.05). The intrinsic capacity of increase of T. fuscum ranged between 0.29 and 0.37 when parasitizing the adult males and females and between 0.18 and 0.21 when parasitizing the larval males and females. Percent parasitism of F. fusca was estimated in peanut fields. The flowers were the primary site for aggregation of the adults of F. fusca and for the free-living females of T. fuscum to parasitize new hosts. As under laboratory conditions, field parasitism of adult males was less than parasitism of adult females in 2001 and 2002 (P < 0.01 and 0.001, respectively). Our study indicates that T. fuscum is a potential biological control agent capable of suppressing F. fusca populations in peanut. PMID:19262837

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

    SciTech Connect

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

    1991-07-01

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

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

    PubMed

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

    2015-01-01

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

  19. Purification and photobiochemical profile of photosystem 1 from a high-salt tolerant, oleaginous Chlorella (Trebouxiophycaea, Chlorophyta).

    PubMed

    McConnell, Michael D; Lowry, David; Rowan, Troy N; van Dijk, Karin; Redding, Kevin E

    2015-06-01

    The eukaryotic green alga Chlamydomonas reinhardtii has been studied extensively within the biofuel industry as a model organism, as researchers look towards algae to provide chemical feedstocks (i.e., lipids) for the production of liquid transportation fuels. C. reinhardtii, however, is unsuitable for high-level production of such precursors due to its relatively poor lipid accumulation and fresh-water demand. In this study we offer insight into the primary light harvesting and electron transfer reactions that occur during phototropic growth in a high-salt tolerant strain of Chlorella (a novel strain introduced here as NE1401), a single-celled eukaryotic algae also in the phylum Chlorophyta. Under nutrient starvation many eukaryotic algae increase dramatically the amount of lipids stored in lipid bodies within their cell interiors. Microscopy and lipid analyses indicate that Chlorella sp. NE1401 may become a superior candidate for algal biofuels production. We have purified highly active Photosystem 1 (PS1) complexes to study in vitro, so that we may understand further the photobiochemisty of this promising biofuel producer and how its characteristics compare and contrast with that of the better understood C. reinhardtii. Our findings suggest that the PS1 complex from Chlorella sp. NE1401 demonstrates similar characteristics to that of C. reinhardtii with respect to light-harvesting and electron transfer reactions. We also illustrate that the relative extent of the light state transition performed by Chlorella sp. NE1401 is smaller compared to C. reinhardtii, although they are triggered by the same dynamic light stresses.

  20. Critical conditions for ferric chloride-induced flocculation of freshwater algae.

    PubMed

    Wyatt, Nicholas B; Gloe, Lindsey M; Brady, Patrick V; Hewson, John C; Grillet, Anne M; Hankins, Matthew G; Pohl, Phillip I

    2012-02-01

    The effects of algae concentration, ferric chloride dose, and pH on the flocculation efficiency of the freshwater algae Chlorella zofingiensis can be understood by considering the nature of the electrostatic charges on the algae and precipitate surfaces. Two critical conditions are identified which, when met, result in flocculation efficiencies in excess of 90% for freshwater algae. First, a minimum concentration of ferric chloride is required to overcome the electrostatic stabilization of the algae and promote bridging of algae cells by hydroxide precipitates. At low algae concentrations, the minimum amount of ferric chloride required increases linearly with algae concentration, characteristic of flocculation primarily through electrostatic bridging by hydroxide precipitates. At higher algae concentrations, the minimum required concentration of ferric chloride for flocculation is independent of algae concentration, suggesting a change in the primary flocculation mechanism from bridging to sweep flocculation. Second, the algae must have a negative surface charge. Experiments and surface complexation modeling show that the surface charge of C. zofingiensis is negative above a pH of 4.0 ± 0.3 which agrees well with the minimum pH required for effective flocculation. These critical flocculation criteria can be extended to other freshwater algae to design effective flocculation systems.

  1. [Allelopathic effect of artemisinin on green algae].

    PubMed

    Wu, Ye-Kuan; Yuan, Ling; Huang, Jian-Guo; Li, Long-Yun

    2013-05-01

    To study the growth effects of differing concentrations of artemisinin on green algae and to evaluate the ecological risk. The effects of artemisinin on the growth and the content change of chlorophyll, protein, oxygen, conductivity, SOD, CAT, MDA in Chlorella pyrenoidosa and Scenedesmus oblique were studied through 96 h toxicity tests. Artemisinin accelerated the growth of algae at a lower concentration ( <40 microg . L-1) with content increase of chlorophyll or protein and so on, and it inhibited the growth of algae at higher concentration ( >80 microg . L-1). The content of chlorophyll or protein in algae cells reduced with the increasing concentration of artemisinin, exhibiting the good concentration-effect relationship. SOD and CAT activity was stimulated at low concentrations ( <40 microg . L-1 ) and inhibited at high concentrations ( >80 microg . L- 1). However, MDA content increased significantly with the increase of concentration. According to the seven kinds of indicators changes, the time-response and dose-response suggested that the surfactant first hurt in Ch. pyrenoidosa was damaging membrane by changing membrane lipid molecules soluble. And primary mechanism on Chlorophyta cells might be related to the oxidation damage of lipid and other biological large molecules caused by artemisinin. The large-scale intensive planting of Artemisia annua may reduce the surrounding water productivity.

  2. Cloning, expression, purification and characterization of an iron-dependent regulator protein from Thermobifida fusca.

    PubMed

    Granger, Joseph B; Lu, Zeyu; Ferguson, Jordan B; Santa Maria, Peter J; Novak, Walter R P

    2013-12-01

    Iron-dependent regulators (IdeRs) control the transcription of a variety of genes associated with iron homeostasis in Gram-positive bacteria. In this study we report the cloning of a putative IdeR gene from the moderate thermophile Thermobifida fusca into the pET-21a(+) expression vector. The expressed protein, Tf-IdeR, was purified using immobilized metal affinity and size-exclusion chromatography, and yielded approximately 12-16 mg of protein per liter of culture. The purified Tf-IdeR protein binds the tox operator sequence in the presence of divalent metal ions. Two Tf-IdeR binding sites were identified in the T. fusca genome upstream of a putative enterobactin exporter and a putative ABC-type multidrug transporter.

  3. Influence of phosphate on toxicity and bioaccumulation of arsenic in a soil isolate of microalga Chlorella sp.

    PubMed

    Bahar, Md Mezbaul; Megharaj, Mallavarapu; Naidu, Ravi

    2016-02-01

    In this study, the toxicity, biotransformation and bioaccumulation of arsenite and arsenate in a soil microalga, Chlorella sp., were investigated using different phosphate levels. The results indicated that arsenate was highly toxic than arsenite to the alga, and the phosphate limitation in growth media greatly enhanced arsenate toxicity. The uptake of arsenate in algal cells was more than that of arsenite, and the predominant species in the growth media was arsenate after 8 days of exposure to arsenite or arsenate, indicating arsenite oxidation by this microalga. Arsenate reduction was also observed when the alga was incubated in a phosphate-limiting growth medium. Similar to the process of biotransformation, the alga accumulated more arsenic when it was exposed to arsenate and preferably more in a phosphate-limiting condition. Although phosphate significantly influences the biotransformation and bioaccumulation of arsenic, the oxidizing ability and higher accumulation capacity of this alga have great potential for its application in arsenic bioremediation.

  4. Ecological Genetics and Host Range Expansion by Busseola fusca (Lepidoptera: Noctuidae).

    PubMed

    Assefa, Y; Conlong, D E; Van Den Berg, J; Martin, L A

    2015-08-01

    The host plant range of pests can have important consequences for its evolution, and plays a critical role in the emergence and spread of a new pest outbreak. This study addresses the ecological genetics of the indigenous African maize stem borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae), in an attempt to investigate the evolutionary forces that may be involved in the recent host range expansion and establishment of this species in Ethiopian and southern African sugarcane. We used populations from Ethiopia, Zimbabwe, and South Africa to examine whether the host range expansion patterns shared by the Ethiopian and the southern African populations of B. fusca have evolved independently. Base-pair differences in the cytochrome oxidase I (COI) gene were used to characterize haplotype diversity and phylogenetic relationships. There were seven haplotypes among the 30 sequenced individuals collected on four host plant species from 17 localities in the four countries. Of the seven COI haplotypes identified, the two major ones occurred in both sugarcane and maize. Genetic analyses revealed no detectable genetic differentiation between southern African B. fusca populations from maize and sugarcane (FST = 0.019; P = 0.24). However, there was strong evidence of variation in genetic composition between populations of the pest from different geographic regions (FST = 0.948; P < 0.001). The main implication of these findings is that the B. fusca populations in maize in southern Africa are more likely to shift to sugarcane, suggesting that ecological opportunity is an important factor in host plant range expansion by a pest.

  5. Genome Sequence and Analysis of the Soil Cellulolytic ActinomyceteThermobifida fusca

    SciTech Connect

    Lykidis, Athanasios; Mavromatis, Konstantinos; Ivanova, Natalia; Anderson, Iain; Land, Miriam; DiBartolo, Genevieve; Martinez, Michele; Lapidus, Alla; Lucas, Susan; Copeland, Alex; Richardson, Paul; Wilson,David B.; Kyrpides, Nikos

    2007-02-01

    Thermobifida fusca is a moderately thermophilic soilbacterium that belongs to Actinobacteria. 3 It is a major degrader ofplant cell walls and has been used as a model organism for the study of 4secreted, thermostable cellulases. The complete genome sequence showedthat T. fusca has a 5 single circular chromosome of 3642249 bp predictedto encode 3117 proteins and 65 RNA6 species with a coding densityof 85percent. Genome analysis revealed the existence of 29 putative 7glycoside hydrolases in addition to the previously identified cellulasesand xylanases. The 8 glycosyl hydrolases include enzymes predicted toexhibit mainly dextran/starch and xylan 9 degrading functions. T. fuscapossesses two protein secretion systems: the sec general secretion 10system and the twin-arginine translocation system. Several of thesecreted cellulases have 11 sequence signatures indicating theirsecretion may be mediated by the twin-arginine12 translocation system. T.fusca has extensive transport systems for import of carbohydrates 13coupled to transcriptional regulators controlling the expression of thetransporters and14 glycosylhydrolases. In addition to providing anoverview of the physiology of a soil 15 actinomycete, this study presentsinsights on the transcriptional regulation and secretion of16 cellulaseswhich may facilitate the industrial exploitation of thesesystems.

  6. Production and release of selenocyanate by different green freshwater algae in environmental and laboratory samples.

    PubMed

    LeBlanc, Kelly L; Smith, Matthew S; Wallschläger, Dirk

    2012-06-05

    In a previous study, selenocyanate was tentatively identified as a biotransformation product when green algae were exposed to environmentally relevant concentrations of selenate. In this follow-up study, we confirm conclusively the presence of selenocyanate in Chlorella vulgaris culture medium by electrospray mass spectrometry, based on selenium's known isotopic pattern. We also demonstrate that the observed phenomenon extends to other green algae (Chlorella kesslerii and Scenedesmus obliquus) and at least one species of blue-green algae (Synechococcus leopoliensis). Further laboratory experiments show that selenocyanate production by algae is enhanced by addition of nitrate, which appears to serve as a source of cyanide produced in the algae. Ultimately, this biotransformation process was confirmed in field experiments where trace amounts of selenocyanate (0.215 ± 0.010 ppb) were observed in a eutrophic, selenium-impacted river with massive algal blooms, which consisted of filamentous green algae (Cladophora genus) and blue-green algae (Anabaena genus). Selenocyanate abundance was low despite elevated selenium concentrations, apparently due to suppression of selenate uptake by sulfate, and insufficient nitrogen concentrations. Finally, trace levels of several other unidentified selenium-containing compounds were observed in these river water samples; preliminary suggestions for their identities include thioselenate and small organic Se species.

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

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

    PubMed

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

    1988-09-01

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

  9. 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.

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

    PubMed

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

    2015-11-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

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

    PubMed

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

    2015-12-01

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

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

    PubMed

    Liu, Jin; Chen, Feng

    2016-01-01

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

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

    PubMed

    Nakanishi, Koichi; Deuchi, Keiji

    2014-05-01

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

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

    PubMed

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

    2016-07-01

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

  17. [Study on the sorption of 4-octylphenol by freshwater algae].

    PubMed

    Peng, Zhang-e; Yang, Hai-zhen; Wang, Bei-bei; Deng, Nan-sheng

    2009-12-01

    The sorption of 4-octylphenol (4-OP) by two freshwater algae was investigated. Results showed that the sorption of 4-octylphenol by algae was obvious and quick, where 20% of initial 4-OP (2 mg/L) was accumulated by Chlorella vulgaris (CV) and 46% initial 4-OP (2 mg/L) was accumulated by Anabaena cylindrical (AC) after 5 min incubation. The sorption got equilibrium at 1 h after incubation. Langmuir sorption model was good appropriate type for this sorption. The effect of pH value on CV sorption was obvious than that on AC sorption. The sorption capacity of the biomass of two algae increased with the decrease of pH value. The analyzing of interaction between algae and 4-octylphenol was performed by fluorescence spectrum. Results showed that the algae could weaker the fluorescence spectrum intensity of 4-octylphenol and result in red shift of the maximum absorbance wavelength of mixture solution. Based on the results, it was speculated that algae bound with the contamination could use the near UV region of solar radiation and induced the contamination degradation.

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

    PubMed

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

    2015-03-01

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

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

    PubMed

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

    2014-11-01

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

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

    PubMed

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

    2012-08-01

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

  1. The effect of temperature on the development and reproduction of Busseola fusca (Lepidoptera: Noctuidae).

    PubMed

    Glatz, J; du Plessis, H; Van den Berg, J

    2017-02-01

    The effect of temperature on the reproduction and development of Busseola fusca was studied under laboratory conditions. Single male-female pairs were confined to oviposition chambers kept at 15, 20, 26 and 30 ± 1°C and a 14L:10D photoperiod. Data on reproduction parameters were captured daily. Oviposition occurred at all the mentioned temperatures but no fertility was recorded at 30°C. The total number of eggs laid per female moth was between 300 and 400 and the optimum temperature for oviposition and fertility was between 20 and 26°C. Larval development was studied at five different temperature regimes, i.e. 15, 18, 20, 26 and 30 ± 1°C and a 14L:10D photoperiod. The most favourable temperature as well as the upper threshold temperature for larval development was between 26 and 30°C. Total development period was 152.6-52.6 days, respectively, at 15°C, and 26-30°C. The thermal constants for B. fusca was 99.50, 536.48, 246.25 and 893.66°D and lower temperature thresholds were 10.36, 8.14, 8.99 and 8.84°C, for completion of the egg, larval, pupal and egg-to-adult stages, respectively. Results on the thermal constants and lower and upper threshold temperatures of B. fusca can be used to predict the impact of climate change on the distribution and population growth of this pest.

  2. Responses of the tropical gorgonian coral Eunicea fusca to ocean acidification conditions

    NASA Astrophysics Data System (ADS)

    Gómez, C. E.; Paul, V. J.; Ritson-Williams, R.; Muehllehner, N.; Langdon, C.; Sánchez, J. A.

    2015-06-01

    Ocean acidification can have negative repercussions from the organism to ecosystem levels. Octocorals deposit high-magnesium calcite in their skeletons, and according to different models, they could be more susceptible to the depletion of carbonate ions than either calcite or aragonite-depositing organisms. This study investigated the response of the gorgonian coral Eunicea fusca to a range of CO2 concentrations from 285 to 4,568 ppm (pH range 8.1-7.1) over a 4-week period. Gorgonian growth and calcification were measured at each level of CO2 as linear extension rate and percent change in buoyant weight and calcein incorporation in individual sclerites, respectively. There was a significant negative relationship for calcification and CO2 concentration that was well explained by a linear model regression analysis for both buoyant weight and calcein staining. In general, growth and calcification did not stop in any of the concentrations of pCO2; however, some of the octocoral fragments experienced negative calcification at undersaturated levels of calcium carbonate (>4,500 ppm) suggesting possible dissolution effects. These results highlight the susceptibility of the gorgonian coral E. fusca to elevated levels of carbon dioxide but suggest that E. fusca could still survive well in mid-term ocean acidification conditions expected by the end of this century, which provides important information on the effects of ocean acidification on the dynamics of coral reef communities. Gorgonian corals can be expected to diversify and thrive in the Atlantic-Eastern Pacific; as scleractinian corals decline, it is likely to expect a shift in these reef communities from scleractinian coral dominated to octocoral/soft coral dominated under a "business as usual" scenario of CO2 emissions.

  3. A case of yellow fever in a brown howler (Alouatta fusca) in Southern Brazil.

    PubMed

    Sallis, Eliza Simone Viégas; de Barros, Vera Lúcia Reis Souza; Garmatz, Shana Letícia; Fighera, Rafael Almeida; Graça, Dominguita Lühers

    2003-11-01

    Many brown howlers (Alouatta fusca) have died in a 3-month period in a subtropical forest in Southern Brazil. One was examined after a systemic illness. According to clinical signs, and necropsy and histopathology findings, yellow fever virus (YFV) infection was suspected. Tissue sections from liver, kidney, and lymphoid organs were screened by immunohistochemistry for YFV antigens. Cells within those tissues stained positively with a polyclonal antibody against YFV antigens (1:1,600 dilution), and yellow fever was diagnosed for the first time in the brown howler in the area.

  4. Ecology of the African Maize Stalk Borer, Busseola fusca (Lepidoptera: Noctuidae) with Special Reference to Insect-Plant Interactions.

    PubMed

    Calatayud, Paul-André; Le Ru, Bruno P; van den Berg, Johnnie; Schulthess, Fritz

    2014-07-08

    Busseola fusca (Lepidoptera: Noctuidae) is an important pest of maize and sorghum in sub-Saharan Africa. One century after its first description by Fuller in 1901, inaccurate information based on earlier reports are still propagated on its distribution (e.g., absent from the lower altitudes in East Africa) and host plant range (e.g., feeding on a large range of wild grass species). This review provides updated information on the biology, distribution and genetics of B. fusca with emphasis on insect-plant interactions. Related to this, new avenues of stem borer management are proposed.

  5. Taxonomic characterization of Vorticella fuscaPrecht, 1935 and Vorticella parapulchella n. sp., two marine peritrichs (Ciliophora, Oligohymenophorea) from China.

    PubMed

    Sun, Ping; Song, Weibo; Clamp, John; Al-Rasheid, Khaled A S

    2006-01-01

    Two marine peritrich ciliates, Vorticella fuscaPrecht (1935) and Vorticella parapulchella n. sp. were discovered in the littoral zone of Qingdao, northern China. Their morphology, infraciliature, and silverline system were described using live observation and silver impregnation. The poorly known species V. fusca is redescribed, adding information about the oral infraciliature and pellicular morphology. Vorticella parapulchella n. sp. is superficially similar to Vorticella pulchellaSommer (1951) but is distinguished from it by being markedly smaller and having much more widely spaced pellicular ridges. The infundibular infraciliature of V. parapulchella is extremely unusual in having infundibular polykinety 3 reduced to two rows, one of which has almost disappeared.

  6. Ecology of the African Maize Stalk Borer, Busseola fusca (Lepidoptera: Noctuidae) with Special Reference to Insect-Plant Interactions

    PubMed Central

    Calatayud, Paul-André; Le Ru, Bruno P.; van den Berg, Johnnie; Schulthess, Fritz

    2014-01-01

    Busseola fusca (Lepidoptera: Noctuidae) is an important pest of maize and sorghum in sub-Saharan Africa. One century after its first description by Fuller in 1901, inaccurate information based on earlier reports are still propagated on its distribution (e.g., absent from the lower altitudes in East Africa) and host plant range (e.g., feeding on a large range of wild grass species). This review provides updated information on the biology, distribution and genetics of B. fusca with emphasis on insect-plant interactions. Related to this, new avenues of stem borer management are proposed. PMID:26462824

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

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

    SciTech Connect

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

    2016-02-03

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

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

    PubMed Central

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

    2016-01-01

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

  10. Mixotrophic cultivation of Chlorella for local protein production using agro-food by-products.

    PubMed

    Salati, Silvia; D'Imporzano, Giuliana; Menin, Barbara; Veronesi, Davide; Scaglia, Barbara; Abbruscato, Pamela; Mariani, Paola; Adani, Fabrizio

    2017-04-01

    A local strain of Chlorella vulgaris was cultivated by using cheese whey (CW), white wine lees (WL) and glycerol (Gly), coming from local agro-industrial activities, as C sources (2.2gCL(-1)) to support algae production under mixotrophic conditions in Lombardy. In continuous mode, Chlorella increased biomass production compared with autotrophic conditions by 1.5-2 times, with the best results obtained for the CW substrate, i.e. 0.52gL(-1)d(-1) of algal biomass vs. 0.24gL(-1)d(-1) of algal biomass for autotrophic conditions, and protein content for both conditions adopted close to 500gkg(-1) DM. Mixotrophic conditions gave a much higher energy recovery efficiency (EF) than autotrophic conditions, i.e. organic carbon energy efficiency (EFoc) of 32% and total energy efficiency (Eft) of 8%, respectively, suggesting the potential for the culture of algae as a sustainable practice to recover efficiently waste-C and a means of local protein production.

  11. SEQUENCE AND ANNOTATION OF THE 369-KB NY-2A AND THE 345-KB AR158 VIRUSES THAT INFECT CHLORELLA NC64A

    PubMed Central

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

    2007-01-01

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

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

    SciTech Connect

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

    2015-06-03

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

  13. Simultaneous production of triacylglycerol and high-value carotenoids by the astaxanthin-producing oleaginous green microalga Chlorella zofingiensis.

    PubMed

    Liu, Jin; Mao, Xuemei; Zhou, Wenguang; Guarnieri, Michael T

    2016-08-01

    The production of lipids and astaxanthin, a high-value carotenoid, by Chlorella zofingiensis was investigated under different culture conditions. Comparative analysis revealed a good correlation between triacylglycerol (TAG) and astaxanthin accumulation in C. zofingiensis. Stress conditions promoted cell size and weight and induced the accumulation of neutral lipids, especially TAG and astaxanthin, with a concomitant decrease in membrane lipids. The highest contents of TAG and astaxanthin achieved were 387 and 4.89mgg(-1) dry weight, respectively. A semi-continuous culture strategy was developed to optimize the TAG and astaxanthin productivities, which reached 297 and 3.3mgL(-1)day(-1), respectively. Additionally, astaxanthin accumulation was enhanced by inhibiting de novo fatty acid biosynthesis. In summary, our study represents a pioneering work of utilizing Chlorella for the integrated production of lipids and high-value products and C. zofingiensis has great potential to be a promising production strain and serve as an emerging oleaginous model alga.

  14. Simultaneous Production of Triacylglycerol and High-Value Carotenoids by the Astaxanthin-Producing Oleaginous Green Microalga Chlorella zofingiensis

    SciTech Connect

    Liu, Jin; Mao, Xuemei; Zhou, Wenguang; Guarnieri, Michael T.

    2016-08-01

    The production of lipids and astaxanthin, a high-value carotenoid, by Chlorella zofingiensis was investigated under different culture conditions. Comparative analysis revealed a good correlation between triacylglycerol (TAG) and astaxanthin accumulation in C. zofingiensis. Stress conditions promoted cell size and weight and induced the accumulation of neutral lipids, especially TAG and astaxanthin, with a concomitant decrease in membrane lipids. The highest contents of TAG and astaxanthin achieved were 387 and 4.89 mg g-1 dry weight, respectively. A semi-continuous culture strategy was developed to optimize the TAG and astaxanthin productivities, which reached 297 and 3.3 mg L-1 day-1, respectively. Additionally, astaxanthin accumulation was enhanced by inhibiting de novo fatty acid biosynthesis. In summary, our study represents a pioneering work of utilizing Chlorella for the integrated production of lipids and high-value products and C. zofingiensis has great potential to be a promising production strain and serve as an emerging oleaginous model alga.

  15. Not so monofunctional--a case of thermostable Thermobifida fusca catalase with peroxidase activity.

    PubMed

    Lončar, Nikola; Fraaije, Marco W

    2015-03-01

    Thermobifida fusca is a mesothermophilic organism known for its ability to degrade plant biomass and other organics, and it was demonstrated that it represents a rich resource of genes encoding for potent enzymes for biocatalysis. The thermostable catalase from T. fusca has been cloned and overexpressed in Escherichia coli with a yield of 400 mg/L. Heat treatment of disrupted cells at 60 °C for 1 h resulted in enzyme preparation of high purity; hence, no chromatography steps are needed for large-scale production. Except for catalyzing the dismutation of hydrogen peroxide, TfuCat was also found to catalyze oxidations of phenolic compounds. The catalase activity was comparable to other described catalases while peroxidase activity was quite remarkable with a k obs of nearly 1000 s(-1) for catechol. Site directed mutagenesis was used to alter the ratio of peroxidase/catalase activity. Resistance to inhibition by classic catalase inhibitors and an apparent melting temperature of 74 °C classifies this enzyme as a robust biocatalyst. As such, it could compete with other commercially available catalases while the relatively high peroxidase activity also offers new biocatalytic possibilities.

  16. Decreased seed oil production in FUSCA3 Brassica napus mutant plants.

    PubMed

    Elahi, Nosheen; Duncan, Robert W; Stasolla, Claudio

    2015-11-01

    Canola (Brassica napus L.) oil is extensively utilized for human consumption and industrial applications. Among the genes regulating seed development and participating in oil accumulation is FUSCA3 (FUS3), a member of the plant-specific B3-domain family of transcription factors. To evaluate the role of this gene during seed storage deposition, three BnFUSCA3 (BnFUS3) TILLING mutants were generated. Mutations occurring downstream of the B3 domain reduced silique number and repressed seed oil level resulting in increased protein content in developing seeds. BnFUS3 mutant seeds also had increased levels of linoleic acid, possibly due to the reduced expression of ω-3 FA DESATURASE (FAD3). These observed phenotypic alterations were accompanied by the decreased expression of genes encoding transcription factors stimulating fatty acid (FA) synthesis: LEAFY COTYLEDON1 and 2 (LEC1 and 2) ABSCISIC ACID-INSENSITIVE 3 (BnABI3) and WRINKLED1 (WRI1). Additionally, expression of genes encoding enzymes involved in sucrose metabolism, glycolysis, and FA modifications were down-regulated in developing seeds of the mutant plants. Collectively, these transcriptional changes support altered sucrose metabolism and reduced glycolytic activity, diminishing the carbon pool available for the synthesis of FA and ultimately seed oil production. Based on these observations, it is suggested that targeted manipulations of BnFUS3 can be used as a tool to influence oil accumulation in the economically important species B. napus.

  17. iTRAQ-based quantitative proteomic analysis of Thermobifida fusca reveals metabolic pathways of cellulose utilization.

    PubMed

    Adav, Sunil S; Ng, Chee Sheng; Sze, Siu Kwan

    2011-09-06

    Thermobifida fusca is an aerobic, thermophilic, cellulose degrading bacterium identified in heated organic materials. This study applied iTRAQ quantitative proteomic analysis to the cellular and membrane proteomes of T. fusca grown in presence and absence of cellulose to elucidate the cellular processes induced by cellulose nutrient. Using an iTRAQ-based quantitative proteomic approach, 783 cytosolic and 181 membrane proteins expressed during cellulose hydrolysis were quantified with ≤1% false discovery rate. The comparative iTRAQ quantification revealed considerable induction in the expression levels and up-regulation of specific proteins in cellulosic medium than non-cellulosic medium. The regulated proteins in cellulosic medium were grouped under central carbohydrate metabolism such as glycolysis/gluconeogenesis, pentose phosphate pathways, citric acid cycle, starch, sugars, pyruvate, propanoate and butanoate metabolism; energy metabolism that includes oxidative phosphorylation, nitrogen, methane and sulfur metabolism; fatty acid metabolism, amino acid metabolic pathways, purine and pyrimidine metabolism, and main cellular genetic information processing functions like replication, transcription, translation, and cell wall synthesis; and environmental information processing (membrane transport and signal transduction). The results demonstrated cellulose induced several metabolic pathways during cellulose utilization.

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

    SciTech Connect

    Van Etten, J.L.

    1992-12-31

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

  19. Magnetic separation of algae

    SciTech Connect

    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.

  20. Effect of Chlorella sorokiniana on the biological denitrification of drinking water.

    PubMed

    Petrovič, Aleksandra; Simonič, Marjana

    2015-04-01

    The influence of Chlorella sorokiniana on drinking water's biological denitrification was studied at two different initial nitrate concentrations, 50 and 100 mg/L, respectively. Sucrose and grape juice were used as carbon sources. The experiments showed that the denitrification process in the presence of algae was, even at low concentrations, i.e. 50 mg/L of nitrate, slower than without them, but yet still more than 95% of nitrate was removed in 24 h. It was also discovered that, with the addition of ammonium and urea, the urea interfered much more with the denitrification process, as less than 50% of the initial nitrate was removed. However, algae did not contribute to the nitrate and ammonium removals, as the final concentrations of both in the presence of algae were higher by approx 5%. At 100 mg/L of initial nitrate, the denitrification kinetics in the presence of algae was apparently slower regarding those experiments at lower levels of nitrate and only 65-70% of nitrate was removed over 24 h. Using grape juice instead of sucrose improved the nitrate removal slightly.

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

    PubMed

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

    2012-12-01

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

  2. 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.

  3. Seasonal dispersal patterns of Frankliniella fusca (Thysanoptera: Thripidae) and tomato spotted wilt virus occurrence in central and eastern North Carolina.

    PubMed

    Groves, R L; Walgenbach, J F; Moyer, J W; Kennedy, G G

    2003-02-01

    The seasonal abundance and temporal pattern of Frankliniella fusca Hinds dispersal were monitored from 1996 to 2000 at 12 locations in central and eastern North Carolina. The predominant vector species of tomato spotted wilt virus (TSWV) captured across all locations was F. fusca (98%). The temporal patterns of F. fusca dispersal observed during spring seasons varied among locations in all years except 2000. Regression analysis estimated that times of first flight in the spring seasons varied among locations, whereas flight duration intervals were similar. Temporal patterns of F. fusca captured varied significantly between aerial traps placed 0.1 and 1.0 m above the soil surface. Fewer total thrips were captured at 0.1 m, although thrips dispersal occurred earlier and over a greater time interval compared with 1.0-m traps. Temporal patterns of TSWV occurrence differed among locations in the spring seasons of 1999 and 2000, whereas patterns of virus occurrence were similar during the fall seasons. Patterns of F. filsca dispersal and subsequent TSWV occurrence were synchronous at locations in 1999 and 2000 where the greatest number of TSWV lesions was recorded. Knowledge of the temporal patterns of F. fiasca dispersal and TSWV occurrence may be a useful indicator for describing the time when susceptible crops are at highest risk of TSWV infection.

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

    PubMed

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

    2013-09-01

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

  5. Growth of Chlorella vulgaris and associated bacteria in photobioreactors.

    PubMed

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

    2012-01-01

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

  6. Growth of Chlorella vulgaris and associated bacteria in photobioreactors

    PubMed Central

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

    2012-01-01

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

  7. Interfacing living unicellular algae cells with biocompatible polyelectrolyte-stabilised magnetic nanoparticles.

    PubMed

    Fakhrullin, Rawil F; Shlykova, Lubov V; Zamaleeva, Alsu I; Nurgaliev, Danis K; Osin, Yuri N; García-Alonso, Javier; Paunov, Vesselin N

    2010-10-08

    Green algae are a promising platform for the development of biosensors and bioelectronic devices. Here we report a reliable single-step technique for the functionalisation of living unicellular green algae Chlorella pyrenoidosa with biocompatible 15 nm superparamagnetic nanoparticles stabilised with poly(allylamine hydrochloride). The magnetised algae cells can be manipulated and immobilised using external permanent magnets. The distribution of the nanoparticles on the cell walls of C. pyrenoidosa was studied by optical and fluorescence microscopy, TEM, SEM and EDX spectroscopy. The viability and the magnetic properties of the magnetised algae are studied in comparison with the native cells. The technique may find a number of potential applications in biotechnology and bioelectronics.

  8. The Podosphaera fusca TUB2 gene, a molecular "Swiss Army knife" with multiple applications in powdery mildew research.

    PubMed

    Vela-Corcía, David; Bellón-Gómez, Davinia; López-Ruiz, Francisco; Torés, Juan Antonio; Pérez-García, Alejandro

    2014-02-01

    The powdery mildew fungus Podosphaera fusca (synonym Podosphaera xanthii) is the main causal agent of cucurbit powdery mildew and one of the most important limiting factors for cucurbit production worldwide. Despite the fungus' economic importance, very little is known about the physiological and molecular processes involved in P. fusca biology and pathogenesis. In this study, we isolated and characterised the β-tubulin-encoding gene of P. fusca (PfTUB2) to develop molecular tools with different applications in powdery mildew research. PfTUB2 is predicted to encode a protein of 447 amino acid residues. The coding region is interrupted by six introns that occur at approximately the same positions as the introns present in other fungal TUB2-like genes. Once cloned, the PfTUB2 sequence information was used in different applications. Our results showed that the TUB2 gene is a good marker for molecular phylogenetics in powdery mildew fungi but it is unsuitable for the analysis of intraspecific diversity in P. fusca. The expression of PfTUB2 was proven to be stable in different temperature conditions, supporting its use as a reference gene in quantitative gene expression studies. Furthermore, an allele-specific PCR assay for the detection of resistance to methyl-2-benzimidazole carbamate (MBC) fungicides in P. fusca was developed based on the correlation between the single amino acid change E198A in β-tubulin and the MBC resistance phenotype. Lastly, PfTUB2 was used as a target gene in the development of a high-throughput method to quantify fungal growth in plant tissues.

  9. Alkaloids in Marine Algae

    PubMed Central

    Güven, Kasım Cemal; Percot, Aline; Sezik, Ekrem

    2010-01-01

    This paper presents the alkaloids found in green, brown and red marine algae. Algal chemistry has interested many researchers in order to develop new drugs, as algae include compounds with functional groups which are characteristic from this particular source. Among these compounds, alkaloids present special interest because of their pharmacological activities. Alkaloid chemistry has been widely studied in terrestrial plants, but the number of studies in algae is insignificant. In this review, a detailed account of macro algae alkaloids with their structure and pharmacological activities is presented. The alkaloids found in marine algae may be divided into three groups: 1. Phenylethylamine alkaloids, 2. Indole and halogenated indole alkaloids, 3. Other alkaloids. PMID:20390105

  10. Influence of Host-Plant Surface Chemicals on the Oviposition of the Cereal Stemborer Busseola Fusca.

    PubMed

    Juma, Gerald; Clément, Gilles; Ahuya, Peter; Hassanali, Ahmed; Derridj, Sylvie; Gaertner, Cyrile; Linard, Romain; Le Ru, Bruno; Frérot, Brigitte; Calatayud, Paul-André

    2016-05-01

    The chemical composition of plant surfaces plays a role in selection of host plants by herbivorous insects. Once the insect reaches the plant, these cues determine host acceptance. Laboratory studies have shown that the stem borer Busseola fusca (Lepidoptera: Noctuidae), an important pest of sorghum and maize in sub-Saharan Africa, is able to differentiate between host and non-host plant species. However, no information is available on the cues used by this insect to seek and accept the host plant. Thus, the role of surface phytochemical stimuli on host selection and oviposition by B. fusca was studied in the laboratory using two host plants, sorghum, Sorghum bicolor, and maize, Zea mays, and one non-host plant, Napier grass, Pennisetum purpureum. The numbers of eggs and egg masses deposited on the three plant species were compared first under no-choice and choice conditions. In both cases, more eggs and egg masses were laid on maize and sorghum than on the non-host. Artificial surrogate stems treated with a water or chloroform surface extract of each plant were then compared with surrogate stems treated with, respectively, water or chloroform as controls, under similar conditions. Surrogate stems treated with plant water extracts did not show an increase in oviposition when compared to controls, indicating that the major compounds in these extracts, i.e., simple sugars and free amino acids, are not significantly responsible for the oviposition preference. By contrast, a chloroform extract of sorghum enhanced oviposition on the surrogate stems compared to the control, while those of maize and Napier grass showed no significant effects. Analysis of the chloroform extract of sorghum showed higher amounts of α-amyrin, ß-amyrin, and n-nonacosane compared to those of maize and Napier grass. A blend of the three chemicals significantly increased oviposition compared to the chloroform-treated control, indicating that these compounds are part of the surface chemical

  11. Energy from algae using microbial fuel cells.

    PubMed

    Velasquez-Orta, Sharon B; Curtis, Tom P; Logan, Bruce E

    2009-08-15

    Bioelectricity production from a phytoplankton, Chlorella vulgaris, and a macrophyte, Ulva lactuca was examined in single chamber microbial fuel cells (MFCs). MFCs were fed with the two algae (as powders), obtaining differences in energy recovery, degradation efficiency, and power densities. C. vulgaris produced more energy generation per substrate mass (2.5 kWh/kg), but U. lactuca was degraded more completely over a batch cycle (73 +/- 1% COD). Maximum power densities obtained using either single cycle or multiple cycle methods were 0.98 W/m(2) (277 W/m(3)) using C. vulgaris, and 0.76 W/m(2) (215 W/m(3)) using U. lactuca. Polarization curves obtained using a common method of linear sweep voltammetry (LSV) overestimated maximum power densities at a scan rate of 1 mV/s. At 0.1 mV/s, however, the LSV polarization data was in better agreement with single- and multiple-cycle polarization curves. The fingerprints of microbial communities developed in reactors had only 11% similarity to inocula and clustered according to the type of bioprocess used. These results demonstrate that algae can in principle, be used as a renewable source of electricity production in MFCs.

  12. 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.

  13. Fuscoside E: a strong anti-inflammatory diterpene from Caribbean octocoral Eunicea fusca.

    PubMed

    Reina, Eduardo; Puentes, Carlos; Rojas, Juan; García, Josué; Ramos, Freddy A; Castellanos, Leonardo; Aragón, Marcela; Ospina, Luis F

    2011-10-01

    The screen of 10 soft coral extracts collected from the Colombian Caribbean Sea in the TPA-induced ear edema model allowed us to identify Eunicea fusca extract among others as an interesting source of active compounds. The new diterpene, fuscoside E (1), along with the known fuscoside B (2), fuscol (3), (+)-germacrene D (4) and a mixture of six sterols (5-10), were isolated from this soft coral. Their structures were elucidated by 1D and 2D NMR spectroscopy techniques. Fuscoside E (1) absolute stereochemistry was determined by chiroptical methods. Fuscoside E (1) and B (2) showed strong anti-inflammatory in the above mentioned bioassay. Additionally, fuscoside E (1) and the sterol mixture (5-10) presented antifouling activity against bacterial strains involved in surface colonization.

  14. Heterotrophic Growth and Production of Xanthophylls by Chlorella pyrenoidosa

    PubMed Central

    Theriault, Robert J.

    1965-01-01

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

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

    PubMed

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

    2015-01-01

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

  16. Uptake and accumulation of exogenous docosahexaenoic acid by Chlorella.

    PubMed

    Hayashi, M; Yukino, T; Maruyama, I; Kido, S; Kitaoka, S

    2001-01-01

    Tuna oil or its hydrolysate was added to a culture of Chlorella for its nutritional fortification as a feed for rotifer. Exogenous docosahexaenoic acid (DHA) in its free form was taken up by the cells of Chlorella vulgaris strain K-22 and by other strains, but tuna oil was not taken up by the cells. Accumulated DHA was found by electron microscopy in the cells in oil droplets. All strains of Chlorella used in these experiments took up exogenous DHA into the cells. It seems that the structure of the cell wall did not affect the uptake of DHA into the Chlorella cells.

  17. Modelling and Optimization of Nannochloropsis and Chlorella Growth for Various Locations and Seasons

    NASA Astrophysics Data System (ADS)

    Gharagozloo, P. E.

    2014-12-01

    Efficient production of algal biofuels could reduce dependence on foreign oil providing domestic renewable energy. Algae-based biofuels are attractive for their large oil yield potential despite decreased land use and natural-resource requirements compared to terrestrial energy crops. Important factors controlling algal-lipid productivity include temperature, nutrient availability, salinity, pH, and the light-to-biomass conversion rate. Computational approaches allow for inexpensive predictions of algae-growth kinetics for various bioreactor sizes and geometries without multiple, expensive measurement systems. In this work, we parameterize our physics-based computational algae growth model for the marine Nannochloropsis oceanica and freshwater Chlorella species. We then compare modelling results with experiments conducted in identical raceway ponds at six geographical locations in the United States (Hawaii, California, Arizona, Ohio, Georgia, and Florida) and three seasons through the Algae Testbed Public Private Partnership - Unified Field Studies. Results show that the computational model effectively predicts algae growth in systems across varying environments and identifies the causes for reductions in algal productivities. The model is then used to identify improvements to the cultivation system to produce higher biomass yields. This model could be used to study the effects of scale-up including the effects of predation, depth-decay of light (light extinction), and optimized nutrient and CO2 delivery. As more multifactorial data are accumulated for a variety of algal strains, the model could be used to select appropriate algal species for various geographic and climatic locations and seasons. Applying the model facilitates optimization of pond designs based on location and season.

  18. Construction and operation of microbial fuel cell with Chlorella vulgaris biocathode for electricity generation.

    PubMed

    Wu, Xia-yuan; Song, Tian-shun; Zhu, Xu-jun; Wei, Ping; Zhou, Charles C

    2013-12-01

    In this study, a modified microbial fuel cell (MFC) with a tubular photobioreactor (PHB) configuration as a cathode compartment was constructed by introducing Chlorella vulgaris to the cathode chamber used to generate oxygen in situ. Two types of cathode materials and light/dark cycles were used to test the effect on MFC with algae biocathode. Results showed that the use of algae is an effective approach because these organisms can act as efficient in situ oxygenators, thereby facilitating the cathodic reaction. Dissolved oxygen and voltage output displayed a clear light positive response and were drastically enhanced compared with the abiotic cathode. In particular, carbon paper-coated Pt used as a cathode electrode increased voltage output at a higher extent than carbon felt used as an electrode. The maximum power density of 24.4 mW/m(2) was obtained from the MFC with algae biocathode which utilized the carbon paper-coated Pt as the cathode electrode under intermittent illumination. This density was 2.8 times higher than that of the abiotic cathode. Continuous illumination shortened the algal lifetime. These results demonstrated that intermittent illumination and cathode material-coated catalyst are beneficial to a more efficient and prolonged operation of MFC with C. vulgaris biocathode.

  19. Construction and operation of microbial fuel cell with Chlorella vulgaris biocathode for electricity generation.

    PubMed

    Wu, Xia-yuan; Song, Tian-shun; Zhu, Xu-jun; Wei, Ping; Zhou, Charles C

    2013-12-01

    In this study, a modified microbial fuel cell (MFC) with a tubular photobioreactor (PHB) configuration as a cathode compartment was constructed by introducing Chlorella vulgaris to the cathode chamber used to generate oxygen in situ. Two types of cathode materials and light/dark cycles were used to test the effect on MFC with algae biocathode. Results showed that the use of algae is an effective approach because these organisms can act as efficient in situ oxygenators, thereby facilitating the cathodic reaction. Dissolved oxygen and voltage output displayed a clear light positive response and were drastically enhanced compared with the abiotic cathode. In particular, carbon paper-coated Pt used as a cathode electrode increased voltage output at a higher extent than carbon felt used as an electrode. The maximum power density of 24.4 mW/m2 was obtained from the MFC with algae biocathode which utilized the carbon paper-coated Pt as the cathode electrode under intermittent illumination. This density was 2.8 times higher than that of the abiotic cathode. Continuous illumination shortened the algal lifetime. These results demonstrated that intermittent illumination and cathode material-coated catalyst are beneficial to a more efficient and prolonged operation of MFC with C. vulgaris biocathode.

  20. The Bioconcentration and Degradation of Nonylphenol and Nonylphenol Polyethoxylates by Chlorella vulgaris

    PubMed Central

    Sun, Hong-Wen; Hu, Hong-Wei; Wang, Lei; Yang, Ying; Huang, Guo-Lan

    2014-01-01

    Nonylphenol polyethoxylates (NPnEOs), a major class of nonionic surfactants, can easily enter into aquatic environments through various pathways due to their wide applications, which leads to the extensive existence of their relative stable metabolites, namely nonylphenol (NP) and mono- to tri-ethoxylates. This study investigated the bioconcentration and degradation of NP and NPnEO oligomers (n = 1–12) by a green algae, Chlorella vulgaris. Experimental results showed that C. vulgaris can remove NP from water phase efficiently, and bioconcentration and degradation accounted for approximately half of its loss, respectively, with a 48 h BCF (bioconcentration factor) of 2.42 × 103. Moreover, C. vulgaris could concentrate and degrade NPnEOs, distribution profiles of the series homologues of the NPnEOs in algae and water phase were quite different from the initial homologue profile. The 48 h BCF of the NPnEO homologues increased with the length of the EO chain. Degradation extent of total NPnEOs by C. vulgaris was 95.7%, and only 1.1% remained in water phase, and the other 3.2% remained in the algal cells. The algae removed the NPnEOs mainly through degradation. Due to rapid degradation, concentrations of the long chain NPnEO homologous in both water (n ≥ 2) and the algal phase (n ≥ 5) was quite low at the end of a 48 h experiment. PMID:24445260

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

    PubMed Central

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

    2012-01-01

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

  2. 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.

  3. Impact of changes in broth composition on Chlorella vulgaris cultivation in a membrane photobioreactor (MPBR) with permeate recycle.

    PubMed

    Discart, V; Bilad, M R; Marbelia, L; Vankelecom, I F J

    2014-01-01

    A membrane photobioreactor (MPBR) is a proven and very useful concept in which microalgae can be simultaneously cultivated and pre-harvested. However, the behavior with respect to accumulation of algogenic organic matter, including transparent exopolymeric particles (TEPs), counter ions and unassimilated nutrients due to the recycling of the medium is still unclear, even though the understanding of this behavior is essential for the optimization of microalgae processing. Therefore, the dynamics of these compounds, especially TEPs, during coupled cultivation and harvesting of Chlorella vulgaris in an MPBR with permeate recycle are addressed in this study. Results show that TEPs are secreted during algae cell growth, and that their presence is thus inevitable. In the system with permeate recycle, substances such as counter ions and unassimilated nutrients get accumulated in the system. This was proven to limit the algae growth, together with the occurrence of bioflocculation due to an increasing broth pH.

  4. 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.

  5. Effect of CaCO3(S) nucleation modes on algae removal from alkaline water.

    PubMed

    Choi, Jin Yong; Kinney, Kerry A; Katz, Lynn E

    2016-02-29

    The role of calcite heterogeneous nucleation was studied in a particle coagulation treatment process for removing microalgae from water. Batch experiments were conducted with Scenedesmus sp. and Chlorella sp. in the presence and absence of carbonate and in the presence and absence of Mg to delineate the role of CaCO3(S) nucleation on microalgae removal. The results indicate that effective algae coagulation (e.g., up to 81 % algae removal efficiency) can be achieved via heterogeneous nucleation with CaCO3(S); however, supersaturation ratios between 120 and 200 are required to achieve at least 50% algae removal, depending on ion concentrations. Algae removal was attributed to adsorption of Ca(2+) onto the cell surface which provides nucleation sites for CaCO3(S) precipitation. Bridging of calcite particles between the algal cells led to rapid aggregation and formation of larger flocs. However, at higher supersaturation conditions, algae removal was diminished due to the dominance of homogeneous nucleation of CaCO3(S). Removal of algae in the presence of Ca(2+) and Mg(2+) required higher supersaturation values; however, the shift from heteronucleation to homonucleation with increasing supersaturation was still evident. The results suggest that water chemistry, pH, ionic strength, alkalinity and Ca(2+) concentration can be optimized for algae removal via coagulation-sedimentation.

  6. Outdoor Growth Characterization of an Unknown Microalga Screened from Contaminated Chlorella Culture

    PubMed Central

    Zhou, Weizheng; Zhu, Feifei

    2017-01-01

    Outdoor microalgae cultivation process is threatened by many issues, such as pest pollution and complex, changeable weather. Therefore, it is difficult to have identical growth rate for the microalgae cells and to keep their continuous growth. Outdoor cultivation requires the algae strains not only to have a strong ability to accumulate oil, but also to adapt to the complicated external environment. Using 18S rRNA technology, one wild strain Scenedesmus sp. FS was isolated and identified from the culture of Chlorella zofingiensis. Upon contamination by Scenedesmus sp., the species could quickly replace Chlorella zofingiensis G1 and occupy ecological niche in the outdoor column photobioreactors. The results indicated that Scenedesmus sp. FS showed high alkali resistance. It also showed that even under the condition of a low inoculum rate (OD680, 0.08), Scenedesmus sp. FS could still grow in the outdoor raceway pond under a high alkaline environment. Even under unoptimized conditions, the oil content of Scenedesmus sp. FS could reach more than 22% and C16–C18 content could reach up to 79.68%, showing that this species has the potential for the biodiesel production in the near future. PMID:28357405

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

    PubMed

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

    2016-01-01

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

  8. Outdoor Growth Characterization of an Unknown Microalga Screened from Contaminated Chlorella Culture.

    PubMed

    Huo, Shuhao; Shang, Changhua; Wang, Zhongming; Zhou, Weizheng; Cui, Fengjie; Zhu, Feifei; Yuan, Zhenhong; Dong, Renjie

    2017-01-01

    Outdoor microalgae cultivation process is threatened by many issues, such as pest pollution and complex, changeable weather. Therefore, it is difficult to have identical growth rate for the microalgae cells and to keep their continuous growth. Outdoor cultivation requires the algae strains not only to have a strong ability to accumulate oil, but also to adapt to the complicated external environment. Using 18S rRNA technology, one wild strain Scenedesmus sp. FS was isolated and identified from the culture of Chlorella zofingiensis. Upon contamination by Scenedesmus sp., the species could quickly replace Chlorella zofingiensis G1 and occupy ecological niche in the outdoor column photobioreactors. The results indicated that Scenedesmus sp. FS showed high alkali resistance. It also showed that even under the condition of a low inoculum rate (OD680, 0.08), Scenedesmus sp. FS could still grow in the outdoor raceway pond under a high alkaline environment. Even under unoptimized conditions, the oil content of Scenedesmus sp. FS could reach more than 22% and C16-C18 content could reach up to 79.68%, showing that this species has the potential for the biodiesel production in the near future.

  9. Bell and banana pepper exhibit mature-plant resistance to tomato spotted wilt Tospovirus transmitted by Frankliniella fusca (Thysanoptera: Thripidae).

    PubMed

    Beaudoin, A L P; Kahn, N D; Kennedy, G G

    2009-02-01

    Tomato spotted wilt virus (family Bunyaviridae, genus Tospovirus, TSWV) causes annual economic losses in pepper, Capsicum annuum L., across the southern United States and is transmitted by several species of thrips, including the tobacco thrips, Frankliniella fusca (Hinds). Reduced virus transmission and symptom severity as plant age increases is known as mature-plant resistance. TSWV transmission to pepper plants was examined in three and four age classes in field and greenhouse trials, respectively. In the field trial, 'Camelot' bell pepper plants were exposed to potentially viruliferous F. fusca 37, 51, or 65 d postsowing. Two greenhouse trials of Camelot bell and one trial each of 'Bounty' and 'Pageant' banana pepper plants were exposed to potentially viruliferous F. fusca, 43, 57, 71, or 85; 48, 62, 75, or 90; 42, 56, 70, or 84; and 43, 57, 71, or 85 d postsowing, respectively. Linear and hyperbolic regressions of percentage of infected plants per block on days postsowing indicated mature-plant resistance in all trials. All models were significant, but hyperbolic curves better fit the data than linear models. Hyperbolic models were used to calculate the number of days posttransplant at which a 50% decrease from the predicted percentage of infected plants at transplant age (42 d postsowing) was expected. This was referred to as days posttransplant-50 (DPT50). DPRT50 occurred within 9 days posttransplant age for all trials, indicating that early TSWV management in pepper is critical.

  10. Genome-based metabolic mapping and 13C flux analysis reveal systematic properties of an oleaginous microalga Chlorella protothecoides.

    PubMed

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

    2015-02-01

    Integrated and genome-based flux balance analysis, metabolomics, and (13)C-label profiling of phototrophic and heterotrophic metabolism in Chlorella protothecoides, an oleaginous green alga for biofuel. The green alga Chlorella protothecoides, capable of autotrophic and heterotrophic growth with rapid lipid synthesis, is a promising candidate for biofuel production. Based on the newly available genome knowledge of the alga, we reconstructed the compartmentalized metabolic network consisting of 272 metabolic reactions, 270 enzymes, and 461 encoding genes and simulated the growth in different cultivation conditions with flux balance analysis. Phenotype-phase plane analysis shows conditions achieving theoretical maximum of the biomass and corresponding fatty acid-producing rate for phototrophic cells (the ratio of photon uptake rate to CO2 uptake rate equals 8.4) and heterotrophic ones (the glucose uptake rate to O2 consumption rate reaches 2.4), respectively. Isotope-assisted liquid chromatography-mass spectrometry/mass spectrometry reveals higher metabolite concentrations in the glycolytic pathway and the tricarboxylic acid cycle in heterotrophic cells compared with autotrophic cells. We also observed enhanced levels of ATP, nicotinamide adenine dinucleotide (phosphate), reduced, acetyl-Coenzyme A, and malonyl-Coenzyme A in heterotrophic cells consistently, consistent with a strong activity of lipid synthesis. To profile the flux map in experimental conditions, we applied nonstationary (13)C metabolic flux analysis as a complementing strategy to flux balance analysis. The result reveals negligible photorespiratory fluxes and a metabolically low active tricarboxylic acid cycle in phototrophic C. protothecoides. In comparison, high throughput of amphibolic reactions and the tricarboxylic acid cycle with no glyoxylate shunt activities were measured for heterotrophic cells. Taken together, the metabolic network modeling assisted by experimental metabolomics and (13)C

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

    DOE PAGES

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

    2014-12-15

    We report that integrated and genome-based flux balance analysis, metabolomics, and 13C-label profiling of phototrophic and heterotrophic metabolism in Chlorella protothecoides, an oleaginous green alga for biofuel. The green alga Chlorella protothecoides, capable of autotrophic and heterotrophic growth with rapid lipid synthesis, is a promising candidate for biofuel production. Based on the newly available genome knowledge of the alga, we reconstructed the compartmentalized metabolic network consisting of 272 metabolic reactions, 270 enzymes, and 461 encoding genes and simulated the growth in different cultivation conditions with flux balance analysis. Phenotype-phase plane analysis shows conditions achieving theoretical maximum of the biomass andmore » corresponding fatty acid-producing rate for phototrophic cells (the ratio of photon uptake rate to CO2 uptake rate equals 8.4) and heterotrophic ones (the glucose uptake rate to O2 consumption rate reaches 2.4), respectively. Isotope-assisted liquid chromatography-mass spectrometry/mass spectrometry reveals higher metabolite concentrations in the glycolytic pathway and the tricarboxylic acid cycle in heterotrophic cells compared with autotrophic cells. We also observed enhanced levels of ATP, nicotinamide adenine dinucleotide (phosphate), reduced, acetyl-Coenzyme A, and malonyl-Coenzyme A in heterotrophic cells consistently, consistent with a strong activity of lipid synthesis. To profile the flux map in experimental conditions, we applied nonstationary 13C metabolic flux analysis as a complementing strategy to flux balance analysis. We found that the result reveals negligible photorespiratory fluxes and a metabolically low active tricarboxylic acid cycle in phototrophic C. protothecoides. In comparison, high throughput of amphibolic reactions and the tricarboxylic acid cycle with no glyoxylate shunt activities were measured for heterotrophic cells. Lastly, taken together, the metabolic network modeling assisted

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

    SciTech Connect

    Qingyu Wu )

    1992-01-01

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

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

    PubMed Central

    He, Xi; Dai, Junbiao; Wu, Qingyu

    2016-01-01

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

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

    PubMed

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

    2016-08-01

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

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

    SciTech Connect

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

    1989-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  17. Production of algal biomass (Chlorella vulgaris) using sediment microbial fuel cells.

    PubMed

    Jeon, Hyeon Jin; Seo, Kyu-won; Lee, Sang Hyun; Yang, Yung-Hun; Kumaran, Rangarajulu Senthil; Kim, Sunghyun; Hong, Seok Won; Choi, Yong Su; Kim, Hyung Joo

    2012-04-01

    In this study, a novel algal biomass production method using a sediment microbial fuel cell (SMFC) system was assessed. Under the experimental conditions, CO(2) generation from the SMFC and its rate of increase were found to be dependent on the current generated from the SMFC. However, the CH(4) production rate from the SMFC was inhibited by the generation of current. When Chlorella vulgaris was inoculated into the cathode compartment of the SMFC and current was generated under 10 Ω resistance, biomass production from the anode compartment was observed to be closely associated with the rate of current generation from the SMFC. The experimental results demonstrate that 420 mg/L of algae (dry cell weight) was produced when the current from the SMFC reached 48.5 mA/m(2). Therefore, SMFC could provide a means for producing algal biomass via CO(2) generated by the oxidation of organics upon current generation.

  18. 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.

  19. 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.

  20. Impact of algal organic matter released from Microcystis aeruginosa and Chlorella sp. on the fouling of a ceramic microfiltration membrane.

    PubMed

    Zhang, Xiaolei; Devanadera, Ma Catriona E; Roddick, Felicity A; Fan, Linhua; Dalida, Maria Lourdes P

    2016-10-15

    Algal blooms lead to the secretion of algal organic matter (AOM) from different algal species into water treatment systems, and there is very limited information regarding the impact of AOM from different species on the fouling of ceramic microfiltration (MF) membranes. The impact of soluble AOM released from Microcystis aeruginosa and Chlorella sp. separately and together in feedwater on the fouling of a tubular ceramic microfiltration membrane (alumina, 0.1 μm) was studied at lab scale. Multi-cycle MF tests operated in constant pressure mode showed that the AOM (3 mg DOC L(-1)) extracted from the cultures of the two algae in early log phase of growth (12 days) resulted in less flux decline compared with the AOM from stationary phase (35 days), due to the latter containing significantly greater amounts of high fouling potential components (protein and humic-like substances). The AOM released from Chlorella sp. at stationary phase led to considerably greater flux decline and irreversible fouling resistance compared with that from M. aeruginosa. The mixture of the AOM (1:1, 3 mg DOC L(-1)) from the two algal species showed more similar flux decline and irreversible fouling resistance to the AOM from M. aeruginosa than Chlorella sp. This was due to the characteristics of the AOM mixture being more similar to those for M. aeruginosa than Chlorella sp. The extent of the flux decline for the AOM mixture after conventional coagulation with aluminium chlorohydrate or alum was reduced by 70%.

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

    SciTech Connect

    Allnutt, F.C.T.

    1985-01-01

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

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

    PubMed Central

    2013-01-01

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

  3. Enhanced mixotrophic growth of microalga Chlorella sp. on pretreated swine manure for simultaneous biofuel feedstock production and nutrient removal.

    PubMed

    Hu, Bing; Min, Min; Zhou, Wenguang; Du, Zhenyi; Mohr, Michael; Chen, Paul; Zhu, Jun; Cheng, Yanling; Liu, Yuhuan; Ruan, Roger

    2012-12-01

    The objectives were to assess the feasibility of using fermented liquid swine manure (LSM) as nutrient supplement for cultivation of Chlorella sp. UMN271, a locally isolated facultative heterotrophic strain, and to evaluate the nutrient removal efficiencies by alga compared with those from the conventionally decomposed LSM-algae system. The results showed that addition of 0.1% (v/v) acetic, propionic and butyric acids, respectively, could promote algal growth, enhance nutrient removal efficiencies and improve total lipids productivities during a 7-day batch cultivation. Similar results were observed when the acidogenic fermentation was applied to the sterilized and raw digested LSM rich in volatile fatty acids (VFAs). High algal growth rate (0.90 d(-1)) and fatty acid content (10.93% of the dry weight) were observed for the raw VFA-enriched manure sample. Finally, the fatty acid profile analyses showed that Chlorella sp. grown on acidogenically digested manure could be used as a feedstock for high-quality biodiesel production.

  4. Development of algae-bacteria granular consortia in photo-sequencing batch reactor.

    PubMed

    Liu, Lin; Fan, Hongyong; Liu, Yuhong; Liu, Chaoxiang; Huang, Xu

    2017-05-01

    The development and properties of algae-bacteria granular consortia, which cultivated with the algae (Chlorella and Scenedesmus) and aerobic granules, was investigated in this experiment. The results indicated that the granular consortia could be successfully developed by selection pressure control, and the algal biomass and extracellular polymeric substances (EPS) concentration in the consortia showed notable correlation with the operating parameters of reactor. The maximum specific removal rates of total nitrogen and phosphate were obtained from the granular consortia with the highest algal biomass, yet the correlation between the fatty acid methyl esters yield and the algal biomass in the consortia was not markedly observed. The seed algae maintained dominance in the phototroph community, whereas the cyanobacteria only occupied a small proportion (5.2-6.5%). Although the bacterial communities with different operational strategies showed significant difference, the dominated bacteria (Comamonadaceae, 18.79-36.25%) in the mature granular consortia were similar.

  5. 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.

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

    NASA Technical Reports Server (NTRS)

    Nienow, J. A.

    2000-01-01

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

  7. Following Ligand Migration Pathways from Picoseconds to Milliseconds in Type II Truncated Hemoglobin from Thermobifida fusca

    PubMed Central

    Marcelli, Agnese; Abbruzzetti, Stefania; Bustamante, Juan Pablo; Feis, Alessandro; Bonamore, Alessandra; Boffi, Alberto; Gellini, Cristina; Salvi, Pier Remigio; Estrin, Dario A.; Bruno, Stefano; Viappiani, Cristiano; Foggi, Paolo

    2012-01-01

    CO recombination kinetics has been investigated in the type II truncated hemoglobin from Thermobifida fusca (Tf-trHb) over more than 10 time decades (from 1 ps to ∼100 ms) by combining femtosecond transient absorption, nanosecond laser flash photolysis and optoacoustic spectroscopy. Photolysis is followed by a rapid geminate recombination with a time constant of ∼2 ns representing almost 60% of the overall reaction. An additional, small amplitude geminate recombination was identified at ∼100 ns. Finally, CO pressure dependent measurements brought out the presence of two transient species in the second order rebinding phase, with time constants ranging from ∼3 to ∼100 ms. The available experimental evidence suggests that the two transients are due to the presence of two conformations which do not interconvert within the time frame of the experiment. Computational studies revealed that the plasticity of protein structure is able to define a branched pathway connecting the ligand binding site and the solvent. This allowed to build a kinetic model capable of describing the complete time course of the CO rebinding kinetics to Tf-trHb. PMID:22792194

  8. Biochemical and biophysical characterization of collagens of marine sponge, Ircinia fusca (Porifera: Demospongiae: Irciniidae).

    PubMed

    Pallela, Ramjee; Bojja, Sreedhar; Janapala, Venkateswara Rao

    2011-07-01

    Collagens were isolated and partially characterized from the marine demosponge, Ircinia fusca from Gulf of Mannar (GoM), India, with an aim to develop potentially applicable collagens from unused and under-used resources. The yield of insoluble, salt soluble and acid soluble forms of collagens was 31.71 ± 1.59, 20.69 ± 1.03, and 17.38 ± 0.87 mg/g dry weight, respectively. Trichrome staining, Scanning & Transmission Electron microscopic (SEM & TEM) studies confirmed the presence of collagen in the isolated, terminally globular irciniid filaments. The partially purified (gel filtration chromatography), non-fibrillar collagens appeared as basement type collagenous sheets under light microscopy whereas the purified fibrillar collagens appeared as fibrils with a repeated band periodicity of 67 nm under Atomic Force Microscope (AFM). The non-fibrillar and fibrillar collagens were seen to have affinity for anti-collagen type IV and type I antibodies raised against human collagens, respectively. The macromolecules, i.e., total protein, carbohydrate and lipid contents within the tissues were also quantified. The present information on the three characteristic irciniid collagens (filamentous, fibrillar and non-fibrillar) could assist the future attempts to unravel the therapeutically important, safer collagens from marine sponges for their use in pharmaceutical and cosmeceutical industries.

  9. DNA sequences of three beta-1,4-endoglucanase genes from Thermomonospora fusca.

    PubMed Central

    Lao, G; Ghangas, G S; Jung, E D; Wilson, D B

    1991-01-01

    The DNA sequences of the Thermomonospora fusca genes encoding cellulases E2 and E5 and the N-terminal end of E4 were determined. Each sequence contains an identical 14-bp inverted repeat upstream of the initiation codon. There were no significant homologies between the coding regions of the three genes. The E2 gene is 73% identical to the celA gene from Microbispora bispora, but this was the only homology found with other cellulase genes. E2 belongs to a family of cellulases that includes celA from M. bispora, cenA from Cellulomonas fimi, casA from an alkalophilic Streptomyces strain, and cellobiohydrolase II from Trichoderma reesei. E4 shows 44% identity to an avocado cellulase, while E5 belongs to the Bacillus cellulase family. There were strong similarities between the amino acid sequences of the E2 and E5 cellulose binding domains, and these regions also showed homology with C. fimi and Pseudomonas fluorescens cellulose binding domains. PMID:1904434

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

    PubMed

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

    2015-08-01

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

  11. Development of Bio-Oil Commodity Fuel as a Refinery Feedstock from High Impact Algae Biomass

    SciTech Connect

    Kastner, James; Mani, Sudhagar; Das, K. C.; Hilten, Roger; Jena, Umakanta

    2014-11-30

    A two-stage hydrothermal liquefaction (HTL) process was developed to 1) reduce nitrogen levels in algal oil, 2) generate a nitrogen rich stream with limited inhibitors for recycle and algae cultivation, and 3) improve downstream catalytic hydrodenitrogenation and hydrodeoxygenation of the algal oil to refinery intermediates. In the first stage, low temperature HTL was conducted at 125, 175, and 225°C at holding times ranging from 1 to 30 min (time at reaction temperature). A consortium of three algal strains, namely Chlorella sorokiniana, Chlorella minutissima, and Scenedesmus bijuga were used to grow and harvest biomass in a raceway system – this consortium is called the UGA Raceway strain throughout the report. Subsequent analysis of the final harvested product indicated that only two strains predominated in the final harvest - Chlorella sorokiniana and Scenedesmus bijuga. Two additional strains representing a high protein (Spirulina platensis) and high lipid algae (Nannochloropsis) strains were also used in this study. These strains were purchased from suppliers. S. platensis biomass was provided by Earthrise Nutritionals LLC (Calipatria, CA) in dry powder form with defined properties, and was stored in airtight packages at 4°C prior to use. A Nannochloropsis paste from Reed Mariculture was purchased and used in the two-stage HTL/HDO experiments. The solids and liquids from this low temperature HTL pretreatment step were separated and analyzed, leading to the following conclusions. Overall, these results indicate that low temperature HTL (200-250°C) at short residence times (5-15 min) can be used to lyse algae cells and remove/separate protein and nitrogen before subsequent higher temperature HTL (for lipid and other polymer hydrolysis) and HDO. The significant reduction in nitrogen when coupled with low protein/high lipid algae cultivation methods at scale could significantly improve downstream catalytic HDO results. However, significant barriers and

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

    PubMed

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

    2006-08-01

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

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

    PubMed

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

    2016-04-29

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

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

    PubMed

    2015-09-21

    Although algae-biofuels have many advantages including high areal productivity, algae can be preyed upon by amoebas, protozoans, ciliates, and rotifers, particularly in open pond systems. Thus, these higher organisms need to be controlled. In this study, Chlorella kessleri was used as the algal culture and Brachionus calyciflorus as the source of predation. The effect of sodium hypochlorite (bleach) was tested with the goal of totally inhibiting the rotifer while causing minor inhibition to the alga. The 24-hr LC50 for B. calyciflorus in spring water was 0.198 mg Cl/L while the 24-hr LC50 for C. kessleri was 0.321 mg Cl/L. However, chlorine dissipates rapidly as the algae serves as reductant. Results showed a chlorine dosage between 0.45 to 0.6 mg Cl/L and a dosing interval of two hours created the necessary chlorine concentrations to inhibit predation while letting the algae grow; thus giving algae farmers a tool to prevent pond crashes. Water Environ. Res., 87 (2015).

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

    PubMed

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

    2016-01-01

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

  16. Novel fungal pelletization-assisted technology for algae harvesting and wastewater treatment.

    PubMed

    Zhou, Wenguang; Cheng, Yanling; Li, Yun; Wan, Yiqin; Liu, Yuhuan; Lin, Xiangyang; Ruan, Roger

    2012-05-01

    A novel fungi pelletization-assisted bioflocculation technology was developed for efficient algae harvesting and wastewater treatment. Microalga Chlorella vulgaris UMN235 and two locally isolated fungal species Aspergillus sp. UMN F01 and UMN F02 were used to study the effect of various cultural conditions on pelletization process for fungi-algae complex. The results showed that pH was the key factor affecting formation of fungi-algae pellet, and pH could be controlled by adjusting glucose concentration and fungal spore number added. The best pelletization happened when adding 20 g/L glucose and approximately 1.2E8/L spores in BG-11 medium, under which almost 100% of algal cells were captured onto the pellets with shorter retention time. The fungi-algae pellets can be easily harvested by simple filtration due to its large size (2-5 mm). The filtered fungi-algae pellets were reused as immobilized cells for treatment wastewaters and the nutrient removal rates of 100, 58.85, 89.83, and 62.53 % (for centrate) and 23.23, 44.68, 84.70, and 70.34% (for diluted swine manure wastewater) for ammonium, total nitrogen, total phosphorus, and chemical oxygen demand, respectively, under both 1- and 2-day cultivations. The novel technology developed is highly promising compared with current algae harvesting and biological wastewater treatment technologies in the literature.

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

    NASA Astrophysics Data System (ADS)

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

    1996-05-01

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

  18. Evaluation of oil-producing algae as potential biodiesel feedstock.

    PubMed

    Zhou, XuPing; Ge, HongMei; Xia, Ling; Zhang, Delu; Hu, ChunXiang

    2013-04-01

    This study attempted to connect the dots between laboratory research and the outdoors. Chlorella sp. NJ-18 was selected among seven oil-producing algae cultivated in this study because it had the highest lipid productivity. The nitrogen and phosphorus concentrations for cultivating this Chlorella strain were optimized indoors. This strain was incubated outdoors in a 70 L photobioreactor, containing the favorable nitrogen (8.32 mM urea) and phosphorus (0.18 mM monopotassium phosphate) concentrations. Semi-continuous cultivation was performed by harvesting 30 L biomass and replacing it with fresh medium. The maximum biomass and lipid productivity acquired outdoors were 91.84 and 24.05 mg L(-1) d(-1), respectively. Furthermore, biomass productivity could be maintained at a high level throughout the cultivation process when using the semi-continuous mode, whereas it decreased dramatically in batch cultures. More than 95% of the total fatty acids obtained were C16 and C18, which are the main components for biofuel.

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

    PubMed

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

    2010-04-01

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

  20. Structural Organization of DNA in Chlorella Viruses

    PubMed Central

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

    2012-01-01

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

  1. Effects of fluoride and chloride on the growth of Chlorella pyrenoidosa.

    PubMed

    Li, Q; Wu, Y Y; Wu, Y D

    2013-01-01

    To compare the toxic action of fluoride (F(-)) and chloride (Cl(-)) on freshwater algae, effects of F(-) and Cl(-) on Chlorella pyrenoidosa growth were investigated by determination of the algal biomass and model analysis. Results showed that the exponential growth equation (D = D0 + ae(bT)) may be used to fit the relationship between cell density (D) of C. pyrenoidosa and exposure time (T), but F(-) and Cl(-) have significantly different effects on parameters a (initial quantity of algae at the exponential growth stage) and b (growth constant). In the range of experimental concentrations, F(-) inhibited C. pyrenoidosa growth, and percent inhibition increased with increasing exposure time and F(-) concentration. By contrast, Cl(-) either inhibited or enhanced C. pyrenoidosa growth depending on Cl(-) concentration and exposure time, and percent inhibition increased with increasing Cl(-) concentration but decreased with increasing exposure time. The dose-response equation: I = min + (max - min)/(1 + 10(lgEC50-lgC)) may be used to fit the relationship between percent inhibition (I) and F(-) or Cl(-) concentration (C); however, F(-) was distinct from Cl(-) in terms of effects on parameter 'min'. The EC50 values of F(-) and Cl(-) ranged from 118 to 170 mg/L and 19.73 to 36.33 g/L, respectively; the latter is much higher than the former. Thus F(-) has higher toxicity than Cl(-).

  2. Rapid induction of lipid droplets in Chlamydomonas reinhardtii and Chlorella vulgaris by Brefeldin A.

    PubMed

    Kim, Sangwoo; Kim, Hanul; Ko, Donghwi; Yamaoka, Yasuyo; Otsuru, Masumi; Kawai-Yamada, Maki; Ishikawa, Toshiki; Oh, Hee-Mock; Nishida, Ikuo; Li-Beisson, Yonghua; Lee, Youngsook

    2013-01-01

    Algal lipids are the focus of intensive research because they are potential sources of biodiesel. However, most algae produce neutral lipids only under stress conditions. Here, we report that treatment with Brefeldin A (BFA), a chemical inducer of ER stress, rapidly triggers lipid droplet (LD) formation in two different microalgal species, Chlamydomonas reinhardtii and Chlorella vulgaris. LD staining using Nile red revealed that BFA-treated algal cells exhibited many more fluorescent bodies than control cells. Lipid analyses based on thin layer chromatography and gas chromatography revealed that the additional lipids formed upon BFA treatment were mainly triacylglycerols (TAGs). The increase in TAG accumulation was accompanied by a decrease in the betaine lipid diacylglyceryl N,N,N-trimethylhomoserine (DGTS), a major component of the extraplastidic membrane lipids in Chlamydomonas, suggesting that at least some of the TAGs were assembled from the degradation products of membrane lipids. Interestingly, BFA induced TAG accumulation in the Chlamydomonas cells regardless of the presence or absence of an acetate or nitrogen source in the medium. This effect of BFA in Chlamydomonas cells seems to be due to BFA-induced ER stress, as supported by the induction of three homologs of ER stress marker genes by the drug. Together, these results suggest that ER stress rapidly triggers TAG accumulation in two green microalgae, C. reinhardtii and C. vulgaris. A further investigation of the link between ER stress and TAG synthesis may yield an efficient means of producing biofuel from algae.

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

    SciTech Connect

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

    1998-09-01

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

  4. Alleviating CTAC and Flu combined pollution damage in Chlorella vulgaris by exogenous nitric oxide.

    PubMed

    Li, Qi; Liang, Zhijie; Ge, Fei; Xu, Yin; Yang, Liang; Zeng, Hui

    2014-02-01

    This study investigates the effect of sodium nitroprussiate (SNP), an exogenous NO-donor, on the joint toxicity of binary mixtures of cetyltrimethylammonium chloride (CTAC) and fluoranthene (Flu) (CTAC/Flu), which are representatives for surfactants and polycyclic aromatic hydrocarbons (PAHs) respectively, in a unicellular green alga Chlorella vulgaris (C. vulgaris). The results showed that the addition of low SNP (20μM) alleviated the CTAC/Flu combined pollution damage in C. vulgaris. Supplement of low SNP significantly increased the algae biomass, chlorophyll content, soluble protein content and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) as compared to CTAC/Flu treatment alone. SNP also reduced the content of malondialdehyde (MDA) and the reactive oxygen species (ROS), as compared with CTAC/Flu treated alone. On the contrary, the above phenomena were reversed when high concentration of SNP (100μM) was added. Our study indicated that the damage of the joint action of surfactants and PAHs on hydrobios can be alleviated through protecting against oxidant substances and increasing the activity of antioxidant enzymes with an exogenous supply of NO in certain concentration range.

  5. Evaluation of novel starch-deficient mutants of Chlorella sorokiniana for hyper-accumulation of lipids

    PubMed Central

    Vonlanthen, Sofie; Dauvillée, David; Purton, Saul

    2015-01-01

    When green algae are exposed to physiological stresses such as nutrient deprivation, growth is arrested and the cells channel fixed carbon instead into storage compounds, accumulating first starch granules and then lipid bodies containing triacylglycerides. In recent years there has been significant interest in the commercial exploitation of algal lipids as a sustainable source of biodiesel. Since starch and lipid biosynthesis involves the same C3 precursor pool, it has been proposed that mutations blocking starch accumulation should result in increased lipid yields, and indeed several studies have supported this. The fast-growing, thermotolerant alga Chlorella sorokiniana represents an attractive strain for industrial cultivation. We have therefore generated and characterized starch-deficient mutants of C. sorokiniana and determined whether lipid levels are increased in these strains under stress conditions. One mutant (ST68) is shown to lack isoamylase, whilst two others (ST3 and ST12) are defective in starch phosphorylase. However, we find no significant change in the accumulation or profile of fatty acids in these mutants compared to the wild-type, suggesting that a failure to accumulate starch per se is not sufficient for the hyper-accumulation of lipid, and that more subtle regulatory steps underlie the partitioning of carbon to the two storage products. PMID:26865991

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

    PubMed

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

    2015-11-01

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

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

    PubMed Central

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

    1975-01-01

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

  8. 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.

  9. Influence of ultraviolet irradiation on nutrient-gleaning capacity of two unicellular algae.

    PubMed

    Kumar, H D; Sharma, V; Bisaria, G P

    1975-01-01

    Two unicellular algae, viz., Anacystis nidulans and Chlorella vulgaris, growing in polluted effluents, were isolated in unialgal and bacteria free culture. They were mutagenically exposed to ultraviolet radiation and variant strains endowed with differing capacities for growth and nutrient-gleaning were successfully isolated as distinct clones on agar plates. One such clone each of the two species was tested further and found stable. While these variant strains grew more slowly than untreated controls, statistically significant differences with respect to phosphate and nitrate uptake were found between treated and control strains of the two species.

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

    SciTech Connect

    Van Etten, J.L.

    1986-01-01

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

  11. Inhibitory effects and mechanisms of Hydrilla verticillata (Linn.f.) Royle extracts on freshwater algae.

    PubMed

    Zhang, T-T; He, M; Wu, A-P; Nie, L-W

    2012-03-01

    To pursue an effective way to control freshwater algae, four extracts from a submerged macrophyte Hydrilla verticillata (Linn.f.) Royle were tested to study its inhibitory effects on Anabaena flos-aquae FACHB-245 and Chlorella pyrenoidosa Chick FACHB-9. Extract with the highest inhibiting ability was further studied in order to reveal the inhibitory mechanism. The results demonstrated that H. verticillata extracts inhibited the growth of A. flos-aquae and C. pyrenoidosa, and methanol extract had the highest inhibiting ability. The mechanism underlying the algal growth inhibition involves the superoxide anion radical generation that induces the damage of cell wall and release of intracellular components.

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

    NASA Astrophysics Data System (ADS)

    Bartošová, Alica; Blinová, Lenka; Gerulová, Kristína

    2015-06-01

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

  13. Chlorella sorokiniana Extract Improves Short-Term Memory in Rats.

    PubMed

    Morgese, Maria Grazia; Mhillaj, Emanuela; Francavilla, Matteo; Bove, Maria; Morgano, Lucia; Tucci, Paolo; Trabace, Luigia; Schiavone, Stefania

    2016-09-29

    Increasing evidence shows that eukaryotic microalgae and, in particular, the green microalga Chlorella, can be used as natural sources to obtain a whole variety of compounds, such as omega (ω)-3 and ω-6 polyunsatured fatty acids (PUFAs). Although either beneficial or toxic effects of Chlorella sorokiniana have been mainly attributed to its specific ω-3 and ω-6 PUFAs content, the underlying molecular pathways remain to be elucidated yet. Here, we investigate the effects of an acute oral administration of a lipid extract of Chlorella sorokiniana, containing mainly ω-3 and ω-6 PUFAs, on cognitive, emotional and social behaviour in rats, analysing possible underlying neurochemical alterations. Our results showed improved short-term memory in Chlorella sorokiniana-treated rats compared to controls, without any differences in exploratory performance, locomotor activity, anxiety profile and depressive-like behaviour. On the other hand, while the social behaviour of Chlorella sorokiniana-treated animals was significantly decreased, no effects on aggressivity were observed. Neurochemical investigations showed region-specific effects, consisting in an elevation of noradrenaline (NA) and serotonin (5-HT) content in hippocampus, but not in the prefrontal cortex and striatum. In conclusion, our results point towards a beneficial effect of Chlorella sorokiniana extract on short-term memory, but also highlight the need of caution in the use of this natural supplement due to its possible masked toxic effects.

  14. Micro-columns packed with Chlorella vulgaris immobilised on silica gel for mercury speciation.

    PubMed

    Tajes-Martínez, P; Beceiro-González, E; Muniategui-Lorenzo, S; Prada-Rodríguez, D

    2006-02-28

    A method has been developed for mercury speciation in water by using columns packed with Chlorella vulgaris immobilised on silica gel. The method involves the retention of CH(3)Hg(+) and Hg(2+) in micro-columns prepared by packing immobilised algae in polypropylene tubes, followed by selective and sequential elution with 0.03 and 1.5M HCl for CH(3)Hg(+) and Hg(2+), respectively. The adsorption capacity of the micro-algae for Hg(2+) and CH(3)Hg(+) has been evaluated using free and immobilised C. vulgaris. The efficiency uptake for both species at pH 3 was higher than 97%. Studies were carried out on the effect of retention and elution conditions for both species. Furthermore, the stability of mercury species retained on algae-silica gel micro-columns and lifetime of the columns were also investigated. Hg(2+) showed a higher stability than CH(3)Hg(+) at 0 degrees C (21 and 3 days, respectively) and a better lifetime than for the organic species. The developed method was applied to the analysis of spiked tap, sea and wastewater samples. Recovery studies on tap and filtered seawater provided results between 96+/-3 and 106+/-2 for Hg(2+) and from 98+/-5 to 107+/-5 for CH(3)Hg(+), for samples spiked with single species. For samples spiked with both CH(3)Hg(+) and Hg(2+), the average recoveries varied from 96+/-5 to 99+/-3 and from 103+/-6 to 115+/-5 for Hg(2+) and CH(3)Hg(+), respectively. However, the percentages of retention and elution on wastewater and unfiltered seawater were only adequate for the inorganic species.

  15. Structure and functional analysis of the siderophore periplasmic binding protein from the fuscachelin gene cluster of Thermobifida fusca.

    PubMed

    Li, Kunhua; Bruner, Steven D

    2016-01-01

    Iron acquisition is a complex, multicomponent process critical for most organisms' survival and virulence. Small iron chelating molecules, siderophores, mediate transport as key components of common pathways for iron assimilation in many microorganisms. The chemistry and biology of the extraordinary tight and specific metal binding siderophores is of general interest in terms of host/guest chemistry and is a potential target toward the development of therapeutic treatments for microbial virulence. The siderophore pathway of the moderate thermophile, Thermobifida fusca, is an excellent model system to study the process in Gram-positive bacteria. Here we describe the structure and characterization of the siderophore periplasmic binding protein, FscJ from the fuscachelin gene cluster of T. fusca. The structure shows a di-domain arrangement connected with a long α-helix hinge. Several X-ray structures detail ligand-free conformational changes at different pH values, illustrating complex interdomain flexibility of the siderophore receptors. We demonstrated that FscJ has a unique recognition mechanism and details the binding interaction with ferric-fuscachelin A through ITC and docking analysis. The presented work provides a structural basis for the complex molecular mechanisms of siderophore recognition and transportation.

  16. Coagulation-membrane filtration of Chlorella vulgaris.

    PubMed

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

    2012-03-01

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

  17. Differential expression of the CrV1 haemocyte inactivation-associated polydnavirus gene in the African maize stem borer Busseola fusca (Fuller) parasitized by two biotypes of the endoparasitoid Cotesia sesamiae (Cameron).

    PubMed

    Gitau, C W; Gundersen-Rindal, D; Pedroni, M; Mbugi, P J; Dupas, S

    2007-07-01

    Polydnaviruses are rarely studied for their natural variation in immune suppressive abilities. The polydnavirus harboring braconid Cotesia sesamiae, a widespread endoparasitoid of Busseola fusca and Sesamia calamistis in sub-Saharan Africa exists as two biotypes. In Kenya, the western biotype completes development in B. fusca larvae. However, eggs of the coastal C. sesamiae are encapsulated in this host and ultimately, no parasitoids emerge from parasitized B. fusca larvae. Both biotypes develop successfully in S. calamistis larvae. Encapsulation activity by B. fusca larvae towards eggs of the avirulent C. sesamiae was detectable six hours post-parasitization. The differences in encapsulation of virulent and avirulent strains were associated with differences in nucleotide sequences and expression of a CrV1 polydnavirus (PDV) gene, which is associated with haemocyte inactivation in the Cotesia rubecula/Pieris rapae system. CrV1 expression was faint or absent in fat body and haemolymph samples from B. fusca parasitized by the avirulent C. sesamiae, which exhibited encapsulation of eggs. Expression was high in fat body and haemolymph samples from both B. fusca and S. calamistis larvae parasitized by the virulent C. sesamiae, encapsulation in the former peaking at the same time points as CrV1 expression in the latter. Non synonymous difference in CrV1 gene sequences between virulent and avirulent wasp suggests that variations in B. fusca parasitism by C. sesamiae may be due to qualitative differences in CrV1-haemocyte interactions.

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

    PubMed

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

    2016-11-05

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

  19. Effectiveness of algae in the treatment of a wood-based pulp and paper industry wastewater.

    PubMed

    Tarlan, Esra; Dilek, Filiz B; Yetis, Ulku

    2002-08-01

    In this study, the ability of algae to treat a wood-based pulp and paper industry wastewater was investigated. Tests were performed in batch reactors seeded with a mixed culture of algae. Under different lighting and initial wastewater strength conditions, changes in COD, AOX and color contents of reactors were followed with time. Algae were found to remove up to 58% of COD, 84% of color and 80% of AOX from pulp and paper industry wastewaters. No remarkable differences were observed in COD and color when light intensity and wastewater strength were changed, while AOX removals were strongly affected. Algal species identification studies revealed that some green algae (Chlorella) and diatom species were dominant in the treatment. The study also showed that algae grew mixotrophically, while the main mechanism of color and organics removal from pulping effluents was partly metabolism and partly metabolic conversion of colored and chlorinated molecules to non-colored and non-chlorinated molecules. Adsorption onto algal biomass was not so effective.

  20. Resurrection kinetics of photosynthesis in desiccation-tolerant terrestrial green algae (Chlorophyta) on tree bark.

    PubMed

    Lüttge, U; Büdel, B

    2010-05-01

    The rough bark of orchard trees (Malus) around Darmstadt is predominantly covered in red to purple-brown layers (biofilms) of epiphytic terrestrial alga of Trentepohlia umbrina. The smooth bark of forest trees (Fagus sylvatica L. and Acer sp.) in the same area is covered by bright green biofilms composed of the green algae Desmococcus, Apatococcus and Trebouxia, with a few cells of Coccomyxa and 'Chlorella' trebouxioides between them. These algae are desiccation tolerant. After samples of bark with the biofilms were kept in dry air in darkness for various periods of time, potential quantum yield of PSII, F(v)/F(m), recovered during rehydration upon rewetting. The kinetics and degree of recovery depended on the length of time that the algae were kept in dry air in the desiccated state. Recovery was better for green biofilm samples, i.e. quite good even after 80 days of desiccation (F(v)/F(m) = ca. 50% of initial value), than the red samples, where recovery was only adequate up to ca. 30-40 days of desiccation (F(v)/F(m) = ca. 20-55% of initial value). It is concluded that the different bark types constitute different ecophysiological niches that can be occupied by the algae and that can be distinguished by their capacity to recover from desiccation after different times in the dry state.

  1. Energetic response of Chlorella vulgaris to alpha radiation and PCB stress

    SciTech Connect

    Schaffer, S.A.

    1982-01-01

    This research project has evaluated the bioenergetic response of the green alga Chlorella vulgaris following acute exposure to either the physical stress of radiation or the chemical stress of PCBs. After exposure, changes in survival or growth, adenylate pools (ATP, ADP, and AMP), CO/sub 2/ fixation and oxygen evolution and uptake were measured. By employing anaerobic conditions, or the electron transport inhibitor DCMU or dark conditions separately and in specific combinations, this study evaluated the response of three separate algal ATP producing mechanisms (respiration, total and cyclic photophosphorylation) to alpha radiation or PCB. The use of the adenylate energy charge ratio as an indicator of stress was also evaluated. The results of the radiation experiments indicated that alpha particle exposure between 25 to 275 rads caused a one-hour latent demand for ATP due to radioinduced DNA repair. In order to compensate for this ATP demand, nonessential utilization of ATP was decreased by slowing the rate of carbon fixation. The results also suggest that use of radiation as a tool to study algal physiology. The data obtained from the PCB experiments again showed each phosphorylation mechanism to be insensitive to 10, 100 and 200 ppm Aroclor 1254 exposures. Data suggest, however, that PCBs caused an increased photosynthetic rate, and total adenylate pool with decreased growth. The use of the adenylate energy charge ratio as a stress indicator was assessed. Because this ratio did not fluctuate at doses of radiation or PCBs that caused reduced survival and growth rates, this study concluded that for Chlorella the adenylate energy charge ration was a poor indicator of sublethal stress.

  2. Metabolic engineering of a laboratory-evolved Thermobifida fusca muC strain for malic acid production on cellulose and minimal treated lignocellulosic biomass.

    PubMed

    Deng, Yu; Mao, Yin; Zhang, Xiaojuan

    2016-01-01

    Malic acid is mainly used as an acidulant and taste enhancer in the beverage and food industry. Previously, a mutant strain Thermobifida fusca muC, obtained by adaptive evolution was found to accumulate malic acid on cellulose with low yield. In this study, the malic acid synthesis pathway in T. fusca muC was confirmed to be from phosphoenolpyruvate to oxaloacetate, followed by reduction of oxaloacetate to malate. To increase the yield of malic acid by the muC strain significantly, the carbon flux from pyruvate was redirected to oxaloacetate by expressing an exogenous pyruvate carboxylase (PCx) gene from Corynebacterium glutamicum ATCC 13032 in the chromosome of T. fusca muC-16. The yield of malic acid in the engineered strain muC-16 was increased by 47.9% compared to the parent strain muC. The muC-16 strain was then grown on ∼100 g/L cellulose and the highest titer of malic acid was 62.76 g/L by batch fermentation. T. fusca muC-16 strain converted milled corn stover to malic acid with the highest titer of 21.47 g/L with minimal treatment.

  3. Nitrous Oxide (N2O) production in axenic Chlorella vulgaris microalgae cultures: evidence, putative pathways, and potential environmental impacts

    NASA Astrophysics Data System (ADS)

    Guieysse, B.; Plouviez, M.; Coilhac, M.; Cazali, L.

    2013-10-01

    Using antibiotic assays and genomic analysis, this study demonstrates nitrous oxide (N2O) is generated from axenic Chlorella vulgaris cultures. In batch assays, this production is magnified under conditions favouring intracellular nitrite accumulation, but repressed when nitrate reductase (NR) activity is inhibited. These observations suggest N2O formation in C. vulgaris might proceed via NR-mediated nitrite reduction into nitric oxide (NO) acting as N2O precursor via a pathway similar to N2O formation in bacterial denitrifiers, although NO reduction to N2O under oxia remains unproven in plant cells. Alternatively, NR may reduce nitrite to nitroxyl (HNO), the latter being known to dimerize to N2O under oxia. Regardless of the precursor considered, an NR-mediated nitrite reduction pathway provides a unifying explanation for correlations reported between N2O emissions from algae-based ecosystems and NR activity, nitrate concentration, nitrite concentration, and photosynthesis repression. Moreover, these results indicate microalgae-mediated N2O formation might significantly contribute to N2O emissions in algae-based ecosystems (e.g. 1.38-10.1 kg N2O-N ha-1 yr-1 in a 0.25 m deep raceway pond operated under Mediterranean climatic conditions). These findings have profound implications for the life cycle analysis of algae biotechnologies and our understanding of the global biogeochemical nitrogen cycle.

  4. The reduction of Chlorella vulgaris concentrations through UV-C radiation treatments: A nature-based solution (NBS).

    PubMed

    Chen, Erika S; Bridgeman, Thomas B

    2017-03-25

    Algal blooms have become a pressing issue in inland freshwater systems on local and global scales. A plausible approach to reducing algae without the use of chemical/biological agents is through the use of UV-C radiation from lamps potentially powered by in situ solar panels to eliminate algae. Yet, the quantitative scientific base has not been established. Our objective is to conduct a controlled experiment to quantify the effectiveness of UV-C radiation on the reduction of Chlorella vulgaris, a common algal species in the Great Lakes region. A full factorial design of three intensities of UV-C radiation (0, 15, and 30W) and three sources of C. vulgaris was constructed to test the corresponding hypotheses. Empirical models were constructed to predict the reductions. UV-C radiation effectively reduced the algal concentration with clear differences by radiation level and source of algal water. Algal concentration decreased exponentially over time, with distinct decreasing trends among the radiation intensities and the samples. With 15W UV-C radiation, algal concentration of three samples were reduced to 75.3%, 51.5%, and 70.0% of the initial level within an hour, respectively. We also found a clear density-dependent reduction rate by UV radiation. Using this information, more efficient treatment systems could be constructed and implemented for cleaning algae-contaminated water.

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

    PubMed

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

    2016-03-10

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

  6. [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.

  7. Converting carbohydrates extracted from marine algae into ethanol using various ethanolic Escherichia coli strains.

    PubMed

    Lee, Soojin; Oh, Younghoon; Kim, Donghyun; Kwon, Doyeon; Lee, Choulgyun; Lee, Jinwon

    2011-07-01

    Marine algae, which make up about 80% of the world's living organisms, contain many energy sources, such as sugars and lipids. Therefore, the possibility of utilizing structural carbohydrates from marine algae for bioethanol production has been studied. In order to obtain monosaccharides, Undaria pinnatifida, Chlorella vulgaris, and Chlamydomonas reinhardtii were used for the saccharification experiments. The pretreatment was carried out by dilute acid hydrolysis and enzymatic treatment. To find the optimal conditions, experiments were performed at several temperatures, acid concentrations, pH conditions and durations. To test bioethanol production, several ethanolic E. coli W3110 strains, which were developed previously, were used. The maximum yield of bioethanol, 0.4 g ethanol/g biomass, was achieved with pretreated C. vulgaris and E. coli SJL2526, derived from wild-type E. coli W3110 and which includes the adhB, pdc, galP, and glk genes.

  8. 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.

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

    SciTech Connect

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

    1987-12-01

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

  10. Pretreatment for simultaneous production of total lipids and fermentable sugars from marine alga, Chlorella sp.

    PubMed

    Lee, Choon-Geun; Kang, Do-Hyung; Lee, Dong-Bog; Lee, Hyeon-Yong

    2013-11-01

    The goal of this study was to determine the optimal pretreatment process for the extraction of lipids and reducing sugars to facilitate the simultaneous production of biodiesel and bioethanol from the marine microalga Chorella sp. With a single pretreatment process, the optimal ultrasonication pretreatment process was 10 min at 47 KHz, and extraction yields of 6.5 and 7.1 (percentage, w/w) of the lipids and reducing sugars, respectively, were obtained. The optimal microwave pretreatment process was 10 min at 2,450 MHz, and extraction yields of 6.6 and 7.0 (percentage, w/w) of the lipids and reducing sugars, respectively, were obtained. Lastly, the optimal high-pressure homogenization pretreatment process was two cycles at a pressure of 20,000 psi, and extraction yields of 12.5 and 12.8 (percentage, w/w) of the lipids and reducing sugars, respectively, were obtained. However, because the single pretreatment processes did not markedly improve the extraction yields compared to the results of previous studies, a combination of two pretreatment processes was applied. The yields of lipids and reducing sugars from the combined application of the high-pressure homogenization process and the microwave process were 24.4 and 24.9 % (w/w), respectively, which was up to three times greater than the yields obtained using the single pretreatment processes. Furthermore, the oleic acid content, which is a fatty acid suitable for biodiesel production, was 23.39 % of the fatty acids (w/w). The contents of glucose and xylose, which are among the fermentable sugars useful for bioethanol production, were 77.5 and 13.3 % (w/w) of the fermentable sugars, respectively, suggesting the possibility of simultaneously producing biodiesel and bioethanol. Based on the results of this study, the combined application of the high-pressure homogenization and microwave pretreatment processes is the optimal method to increase the extraction yields of lipids and reducing sugars that are essential for the simultaneous production of biodiesel and bioethanol.

  11. Stearoyl-acyl carrier protein desaturase gene from the oleaginous microalga Chlorella zofingiensis: cloning, characterization and transcriptional analysis.

    PubMed

    Liu, Jin; Sun, Zheng; Zhong, Yujuan; Huang, Junchao; Hu, Qiang; Chen, Feng

    2012-12-01

    The green alga Chlorella zofingiensis can accumulate high level of oleic acid (OA, C18:1△(9)) rich oils in response to stress conditions. To understand the regulation of biosynthesis of fatty acid in particular OA at the molecular level, we cloned and characterized the stearoyl acyl carrier protein (ACP) desaturase (SAD) responsible for OA formation through desaturation of stearic acid (C18:0) from C. zofingiensis. Southern blot indicated that the C. zofingiensis genome contained a single copy of SAD, from which the deduced amino acid sequence shared high identity to the corresponding homologs from other microalgae and higher plants. The desaturation activity of SAD was demonstrated in vitro using C18:0-ACP as a substrate. Stress conditions such as high light (HL), nitrogen deficiency (N(-)), or combination of HL and N(-) (HL + N(-)) drastically up-regulated the transcripts of biotin carboxylase (BC, a subunit of ACCase) and SAD, and therefore induced considerably the cellular accumulation of total fatty acids including OA. Glucose (50 mM) gave rise to the similar up-regulation of the two genes and induction of fatty acid accumulation. The accumulation of intracellular reactive oxygen species was found to be associated with the up-regulation of genes. This is the first report of characterization of Chlorella-derived SAD and the results may contribute to understanding of the mechanisms involved in fatty acid/lipid biosynthesis in microalgae.

  12. Chlorella vulgaris Attenuates Dermatophagoides Farinae-Induced Atopic Dermatitis-Like Symptoms in NC/Nga Mice.

    PubMed

    Kang, Heerim; Lee, Chang Hyung; Kim, Jong Rhan; Kwon, Jung Yeon; Seo, Sang Gwon; Han, Jae Gab; Kim, Byung Gon; Kim, Jong-Eun; Lee, Ki Won

    2015-09-02

    Atopic dermatitis (AD) is a chronic and inflammatory skin disease that can place a significant burden on quality of life for patients. AD most frequently appears under the age of six and although its prevalence is increasing worldwide, therapeutic treatment options are limited. Chlorella vulgaris (CV) is a species of the freshwater green algae genus chlorella, and has been reported to modulate allergy-inducible factors when ingested. Here, we examined the effect of CV supplementation on AD-like symptoms in NC/Nga mice. CV was orally administrated for six weeks while AD-like symptoms were induced via topical application of Dermatophagoides farinae extract (DFE). CV treatment reduced dermatitis scores, epidermal thickness, and skin hydration. Histological analysis also revealed that CV treatment reduced DFE-induced eosinophil and mast cell infiltration into the skin, while analysis of serum chemokine levels indicated that CV treatment downregulated thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) levels. In addition, CV treatment downregulated mRNA expression levels of IL-4 and IFN-γ. Taken together, these results suggest that CV extract may have potential as a nutraceutical ingredient for the prevention of AD.

  13. Chlorella vulgaris Attenuates Dermatophagoides Farinae-Induced Atopic Dermatitis-Like Symptoms in NC/Nga Mice

    PubMed Central

    Kang, Heerim; Lee, Chang Hyung; Kim, Jong Rhan; Kwon, Jung Yeon; Seo, Sang Gwon; Han, Jae Gab; Kim, Byung Gon; Kim, Jong-Eun; Lee, Ki Won

    2015-01-01

    Atopic dermatitis (AD) is a chronic and inflammatory skin disease that can place a significant burden on quality of life for patients. AD most frequently appears under the age of six and although its prevalence is increasing worldwide, therapeutic treatment options are limited. Chlorella vulgaris (CV) is a species of the freshwater green algae genus chlorella, and has been reported to modulate allergy-inducible factors when ingested. Here, we examined the effect of CV supplementation on AD-like symptoms in NC/Nga mice. CV was orally administrated for six weeks while AD-like symptoms were induced via topical application of Dermatophagoides farinae extract (DFE). CV treatment reduced dermatitis scores, epidermal thickness, and skin hydration. Histological analysis also revealed that CV treatment reduced DFE-induced eosinophil and mast cell infiltration into the skin, while analysis of serum chemokine levels indicated that CV treatment downregulated thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) levels. In addition, CV treatment downregulated mRNA expression levels of IL-4 and IFN-γ. Taken together, these results suggest that CV extract may have potential as a nutraceutical ingredient for the prevention of AD. PMID:26404252

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

    PubMed Central

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

    2015-01-01

    Integrated and genome-based flux balance analysis, metabolomics, and 13C-label profiling of phototrophic and heterotrophic metabolism in Chlorella protothecoides, an oleaginous green alga for biofuel. The green alga Chlorella protothecoides, capable of autotrophic and heterotrophic growth with rapid lipid synthesis, is a promising candidate for biofuel production. Based on the newly available genome knowledge of the alga, we reconstructed the compartmentalized metabolic network consisting of 272 metabolic reactions, 270 enzymes, and 461 encoding genes and simulated the growth in different cultivation conditions with flux balance analysis. Phenotype-phase plane analysis shows conditions achieving theoretical maximum of the biomass and corresponding fatty acid-producing rate for phototrophic cells (the ratio of photon uptake rate to CO2 uptake rate equals 8.4) and heterotrophic ones (the glucose uptake rate to O2 consumption rate reaches 2.4), respectively. Isotope-assisted liquid chromatography-mass spectrometry/mass spectrometry reveals higher metabolite concentrations in the glycolytic pathway and the tricarboxylic acid cycle in heterotrophic cells compared with autotrophic cells. We also observed enhanced levels of ATP, nicotinamide adenine dinucleotide (phosphate), reduced, acetyl-Coenzyme A, and malonyl-Coenzyme A in heterotrophic cells consistently, consistent with a strong activity of lipid synthesis. To profile the flux map in experimental conditions, we applied nonstationary 13C metabolic flux analysis as a complementing strategy to flux balance analysis. The result reveals negligible photorespiratory fluxes and a metabolically low active tricarboxylic acid cycle in phototrophic C. protothecoides. In comparison, high throughput of amphibolic reactions and the tricarboxylic acid cycle with no glyoxylate shunt activities were measured for heterotrophic cells. Taken together, the metabolic network modeling assisted by experimental metabolomics and 13C labeling

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

    SciTech Connect

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

    2014-12-15

    We report that integrated and genome-based flux balance analysis, metabolomics, and 13C-label profiling of phototrophic and heterotrophic metabolism in Chlorella protothecoides, an oleaginous green alga for biofuel. The green alga Chlorella protothecoides, capable of autotrophic and heterotrophic growth with rapid lipid synthesis, is a promising candidate for biofuel production. Based on the newly available genome knowledge of the alga, we reconstructed the compartmentalized metabolic network consisting of 272 metabolic reactions, 270 enzymes, and 461 encoding genes and simulated the growth in different cultivation conditions with flux balance analysis. Phenotype-phase plane analysis shows conditions achieving theoretical maximum of the biomass and corresponding fatty acid-producing rate for phototrophic cells (the ratio of photon uptake rate to CO2 uptake rate equals 8.4) and heterotrophic ones (the glucose uptake rate to O2 consumption rate reaches 2.4), respectively. Isotope-assisted liquid chromatography-mass spectrometry/mass spectrometry reveals higher metabolite concentrations in the glycolytic pathway and the tricarboxylic acid cycle in heterotrophic cells compared with autotrophic cells. We also observed enhanced levels of ATP, nicotinamide adenine dinucleotide (phosphate), reduced, acetyl-Coenzyme A, and malonyl-Coenzyme A in heterotrophic cells consistently, consistent with a strong activity of lipid synthesis. To profile the flux map in experimental conditions, we applied nonstationary 13C metabolic flux analysis as a complementing strategy to flux balance analysis. We found that the result reveals negligible photorespiratory fluxes and a metabolically low active tricarboxylic acid cycle in phototrophic C. protothecoides. In comparison, high throughput of amphibolic reactions and the tricarboxylic acid cycle with no glyoxylate shunt activities were measured for heterotrophic cells. Lastly, taken together, the

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

    PubMed

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

    2015-12-01

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

  17. Differential lipid and fatty acid profiles of photoautotrophic and heterotrophic Chlorella zofingiensis: assessment of algal oils for biodiesel production.

    PubMed

    Liu, Jin; Huang, Junchao; Sun, Zheng; Zhong, Yujuan; Jiang, Yue; Chen, Feng

    2011-01-01

    The objective of this study was to document and compare the lipid class and fatty acid composition of the green microalga Chlorella zofingiensis cultivated under photoautotrophic and heterotrophic conditions. Compared with photoautotrophic cells, a 900% increase in lipid yield was achieved in heterotrophic cells fed with 30 g L(-1) of glucose. Furthermore heterotrophic cells accumulated predominantly neutral lipids (NL) that accounted for 79.5% of total lipids with 88.7% being triacylglycerol (TAG); whereas photoautotrophic cells contained mainly the membrane lipids glycolipids (GL) and phospholipids (PL). Together with the much higher content of oleic acid (C18:1) (35.2% of total fatty acids), oils from heterotrophic C. zofingiensis appear to be more feasible for biodiesel production. Our study highlights the possibility of using heterotrophic algae for producing high quality biodiesel.

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

    PubMed

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

    2015-07-23

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

  19. Cellular response of freshwater green algae to perfluorooctanoic acid toxicity.

    PubMed

    Xu, Dongmei; Li, Chandan; Chen, Hong; Shao, Bo

    2013-02-01

    Perfluorooctanoic acid (PFOA) is a kind of persistent organic pollutants and its aquatic eco-toxicity has attracted wide attention; however, the mechanism involved in its toxicity as well as the cell response against PFOA have not been well established. Herein, using single-celled green algae Chlorella pyrenoidosa and Selenastrum capricornutum at the logarithmic growth stage as test organisms, we studied the toxic effects of PFOA on the cell permeability, The 96 h-EC(50) values of PFOA for C. pyrenoidosa and S. capricornutum were 207.46 mg L(-1) and 190.99 mg L(-1), respectively, lower than the 96 h-EC(50) values reported in the literatures. After 96 h of PFOA exposure, the permeability of the cell membranes of both algae was significantly decreased, and the chlorophyll concentration mirrored the trends of algal growth. In both algal species, after a 192-h exposure to a low concentration of PFOA, the activities of superoxide dismutase and catalase were greater than those of the control. At higher concentrations of PFOA, activities of superoxide dismutase and catalase were strongly inhibited. These results indicate that long-term exposure to low levels of PFOA may induce excessive generation of reactive oxygen species in algal cells, causing oxidative damage to cells.

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

    SciTech Connect

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

    1989-11-01

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

  1. In vivo microspectroscopy monitoring of chromium effects on the photosynthetic and photoreceptive apparatus of Eudorina unicocca and Chlorella kessleri.

    PubMed

    Juarez, Angela Beatriz; Barsanti, Laura; Passarelli, Vincenzo; Evangelista, Valter; Vesentini, Nicoletta; Conforti, Visitacion; Gualtieri, Paolo

    2008-11-01

    In microorganisms and plants, chromium (Cr) is not essential for any metabolic process, and can ultimately prove highly deleterious. Due to its widespread industrial use, chromium has become a serious pollutant in diverse environmental settings. The presence of Cr leads to the selection of specific algal populations able to tolerate high levels of Cr compounds. The varying Cr-resistance mechanisms displayed by microorganisms include biosorption, diminished accumulation, precipitation, reduction of Cr(6+) to Cr(3+), and chromate efflux. In this paper we describe the effects of Cr(6+) (the most toxic species) on the photosynthetic and photoreceptive apparatus of two fresh water microalgae, Eudorina unicocca and Chlorella kessleri. We measured the effect of this heavy metal by means of in vivo absorption microspectroscopy of both the thylakoid compartments and the eyespot. The decomposition of the overall absorption spectra in pigment constituents indicates that Cr(6+) effects are very different in the two algae. In E. unicocca the metal induced a complete pheophinitization of the chlorophylls and a modification of the carotenoids present in the eyespot after only 120 h of exposition at a concentration equal or greater than 40 microM, which is the limit for total Cr discharge established by US EPA regulations. In C. kessleri, chromium concentrations a hundred times higher than this limit had no effect on the photosynthetic machinery. The different tolerance level of the two algae is suggested to be due to the different properties of the mucilaginous envelope and cell wall covering, respectively, the colonies of Eudorina and the single cells of Chlorella, which binds chromium cations to a different extent.

  2. Screening high oleaginous Chlorella strains from different climate zones.

    PubMed

    Xu, Jin; Hu, Hanhua

    2013-09-01

    In outdoor cultivation, screening strains adapted to a wide temperature range or suitable strains for different environmental temperatures is of great importance. In this study, triacylglycerol (TAG) content of 23 oil-producing Chlorella strains from different climate zones were analyzed by thin layer chromatography. Four selected Chlorella strains (NJ-18, NJ-7, NMX35N and NMX139N) with rather high TAG content had higher total lipid content compared with Chlorella vulgaris SAG 211-11b. In particular, NJ-18 displayed the highest TAG productivity among the four high oil-producing Chlorella strains. Accumulation of TAGs in strain NMX35N changed a little from 30 to 40°C, showing a desirable characteristic of accumulating TAGs at high temperatures. Our results demonstrated that NJ-18 and NMX35N had suitable fatty acid profiles and good adaption to low and high temperatures respectively. Therefore, cultivation of the two Chlorella strains together might be a good option for economic biodiesel production during the whole seasons of the year.

  3. Leptochlorella corticola gen. et sp. nov. and Kalinella apyrenoidosa sp. nov.: two novel Chlorella-like green microalgae (Trebouxiophyceae, Chlorophyta) from subaerial habitats.

    PubMed

    Neustupa, Jirí; Nemcová, Yvonne; Veselá, Jana; Steinová, Jana; Škaloud, Pavel

    2013-01-01

    The diversity of green microalgae in subaerial habitats remains largely unexplored and a number of new genus- and species-level lineages have been discovered recently. The traditional green algal genus, Chlorella, which accommodated coccoid unicellular green algal species with globular to oval cells, reproducing entirely by autospores, has been found to be polyphyletic. In this study, we provide a detailed characterization of two strains of microalgae isolated from tree bark in the Mediterranean. These algae share the general Chlorella-like morphology and their 18S rRNA and rbcL gene sequences place them in the Trebouxiophyceae. Strain CAUP H8401 forms an independent trebouxiophycean lineage, together with three previously published 18S rRNA gene environmental sequences of undescribed microalgae, which were retrieved from profoundly different habitats. In contrast, strain CAUP H7902 is related to Kalinella bambusicola in the Watanabea clade of the Trebouxiophyceae on the basis of its 18S rRNA gene sequence. This relationship is also supported by the rbcL gene sequence, acquired from the type strain of K. bambusicola. The investigated strains are described as representatives of a novel species in a new genus, Leptochlorella corticola gen. et sp. nov., and a novel species, Kalinella apyrenoidosa sp. nov., according to the International Code of Nomenclature for Algae, Fungi and Plants.

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

    SciTech Connect

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

    1986-01-01

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

  5. 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

  6. Use of xylazine hydrochloride-ketamine hydrochloride for immobilization of wild leopards (Panthera pardus fusca) in emergency situations.

    PubMed

    Belsare, Aniruddha V; Athreya, Vidya R

    2010-06-01

    In India, leopards (Panthera pardus fusca) inhabit human-dominated landscapes, resulting in encounters that require interventions to prevent harm to people, as well as the leopards. Immobilization is a prerequisite for any such intervention. Such emergency field immobilizations have to be carried out with limited tools, often amidst large uncontrollable crowds. An effective and practicable approach is discussed, based on 55 wild leopard immobilizations undertaken between January 2003 and April 2008. A xylazine hydrochloride (1.4 +/- 0.3 mg/kg)--ketamine hydrochloride (5 +/- 2 mg/kg) mixture was used for immobilization of leopards, based on estimated body weight. When weight could not be estimated, a standard initial dose of 50 mg of xylazine--150 mg of ketamine was used. Supplemental doses (50-75 mg) of only ketamine were used as required. No life-threatening adverse effects of immobilization were documented for at least 1 mo postimmobilization.

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

    PubMed

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

    2013-01-01

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

  8. Seed germination ecology of the annual grass Leptochloa panicea ssp. mucronata and a comparison with L. panicoides and L. fusca

    NASA Astrophysics Data System (ADS)

    Baskin, Carol C.; Baskin, Jerry M.; Chester, Edward W.

    1999-09-01

    Leptochloa panicea ssp. mucronata is an annual grass that grows in relatively dry habitats. Requirements for dormancy loss and germination were determined for seeds of this species and compared to those of two species from wet habitats. Seeds of L. panicea were dormant at maturity in autumn, but when exposed to actual or simulated autumn temperatures (e.g. 20/10, 15/6 °C), they entered conditional dormancy and thus germinated to high percentages in light at 35/20 °C. Seeds buried in non-flooded soil exposed to natural seasonal temperature changes in Kentucky (USA) were non-dormant by the following summer and germinated to 80-100 % in light at 25/15, 30/15 and 35/20 °C. Seeds buried in non-flooded soil exhibited an annual conditional dormancy/non-dormancy cycle, with seeds mostly germinating to 80-100 % in light at 30/15 and 35/20 °C throughout the year but to 80-100 % in light at 25/15 °C only in summer. Results for L. panicea were compared to published data for L. panicoides and L. fusca. Whereas seeds of L. panicea buried in flooded soil failed to come out of dormancy, those of L. panicoides, an annual of moist habitats such as mudflats, exhibited an annual conditional dormancy/non-dormancy cycle, and those of L. fusca, a semi-aquatic, required flooding for both dormancy loss and germination. Differences in dormancy breaking and germination responses of seeds of Leptochloa species may help to explain why this genus occupies a wide range of habitats with regard to soil moisture conditions.

  9. Gas Exchange of Algae

    PubMed Central

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

    1967-01-01

    The oxygen production of a photosynthetic gas exchanger containing Chlorella pyrenoidosa (1% packed cell volume) was measured when various concentrations of carbon dioxide were present within the culture unit. The internal carbon dioxide concentrations were obtained by manipulating the entrance gas concentration and the flow rate. Carbon dioxide percentages were monitored by means of electrodes placed directly in the nutrient medium. The concentration of carbon dioxide in the nutrient medium which produced maximal photosynthesis was in the range of 1.5 to 2.5% by volume. Results were unaffected by either the level of carbon dioxide in the entrance gas or the rate of gas flow. Entrance gases containing 2% carbon dioxide flowing at 320 ml/min, 3% carbon dioxide at 135 ml/min, and 4% carbon dioxide at 55 ml/min yielded optimal carbon dioxide concentrations in the particular unit studied. By using carbon dioxide electrodes implanted directly in the gas exchanger to optimize the carbon dioxide concentration throughout the culture medium, it should be possible to design more efficient large-scale units. PMID:4382391

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

    PubMed

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

    2011-10-01

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

  11. Impact of Summer Cattle Grazing on the Sierra Nevada Watershed: Aquatic Algae and Bacteria

    PubMed Central

    Derlet, Robert W.; Richards, John R.; Tanaka, Lidia L.; Hayden, Curtis; Ger, K. Ali; Goldman, Charles R.

    2012-01-01

    Introduction. We evaluated periphytic algal and microbial communities to assess the influence of human and cattle impact on Sierra water quality. Methods. 64 sites (lakes and streams from Lake Tahoe to Sequoia National Park, California) were sampled for suspended indicator bacteria and algae following standardized procedures. The potential for nonpoint pollution was divided into three categories: cattle-grazing areas (C), recreation use areas (R), or remote wildlife areas (W). Results. Periphyton was found at 100% of C sites, 89% of R sites, but only 25% of W sites. Eleven species of periphytic algae were identified, including Zygnema, Ulothrix, Chlorella, Spirogyra, mixed Diatoms, and Cladophoria. Mean benthic algae coverage was 66% at C sites compared to 2% at W sites (P < 0.05). The prevalence of E. coli associated with periphyton was 100% at C sites, 25% of R sites, and 0% of W sites. Mean E. coli CFU/gm of algae detected was: C = 173,000, R = 700, W = 0. (P < 0.05). Analysis of neighboring water for E. coli bacteria >100 CFU/100 mL: C = 91%, R = 8%, W = 0 (P < 0.05). Conclusion. Higher periphytic algal biomass and uniform presence of periphyton-attached E. coli corresponded to watersheds exposed to summer cattle grazing. These differences suggest cattle grazing compromises water quality. PMID:22505950

  12. The removal of thermo-tolerant coliform bacteria by immobilized waste stabilization pond algae.

    PubMed

    Pearson, H W; Marcon, A E; Melo, H N

    2011-01-01

    This study investigated the potential of laboratory- scale columns of immobilized micro-algae to disinfect effluents using thermo-tolerant coliforms (TTC) as a model system. Cells of a Chlorella species isolated from a waste stabilization pond complex in Northeast Brazil were immobilized in calcium alginate, packed into glass columns and incubated in contact with TTC suspensions for up to 24 hours. Five to six log removals of TTC were achieved in 6 hours and 11 log removals in 12 hours contact time. The results were similar under artificial light and shaded sunlight. However little or no TTC removal occurred in the light in columns of alginate beads without immobilized algae present or when the immobilized algae were incubated in the dark suggesting that the presence of both algae and light were necessary for TTC decay. There was a positive correlation between K(b) values for TTC and increasing pH in the effluent from the immobilized algal columns within the range pH 7.2 and 8.9. The potential of immobilized algal technology for wastewater disinfection may warrant further investigation.

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

    PubMed

    Birungi, Z S; Chirwa, E M N

    2015-12-15

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

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

    NASA Astrophysics Data System (ADS)

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

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

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

    PubMed

    Zhang, Shuai; Lin, Daohui; Wu, Fengchang

    2016-07-05

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

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

    PubMed

    Wolf, L

    1997-01-01

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

  17. Long-term outdoor cultivation by perfusing spent medium for biodiesel production from Chlorella minutissima.

    PubMed

    Oh, Sung Ho; Kwon, Min Chul; Choi, Woon Yong; Seo, Yong Chang; Kim, Ga Bin; Kang, Do Hyung; Lee, Shin Young; Lee, Hyeon Yong

    2010-08-01

    A unique perfusion process was developed to maintain high concentrations of marine alga, Chlorella minutissima. This method is based on recycling cells by continuous feeding with warm spent sea water from nuclear power plants, which has very similar properties as sea water. A temperature of at least 30 degrees C in a 200 L photo-bioreactor was maintained in this system by perfusion of the thermal plume for 80 days in the coldest season. The maximum cell concentration and total lipid content was 8.3 g-dry wt./L and 23.2 %, w/w, respectively, under mixotrophic conditions. Lipid production was found to be due to a partially or non-growth related process, which implies that large amounts of biomass are needed for a high accumulation of lipids within the cells. At perfusion rates greater than 1.5 L/h, the temperature of the medium inside the reactor was around 30 degrees C, which was optimal for cell growth. For this system, a perfusion rate of 2.8 L/h was determined to be optimal for maintaining rapid cell growth and lipid production during outdoor cultivation. It was absolutely necessary to maintain the appropriate perfusion rate so that the medium temperature was optimal for cell growth. In addition, the lipids produced using this process were shown to be feasible for biodiesel production since the lipid composition of C. minutissima grown under these conditions consisted of 17 % (w/w) of C(16) and 47% (w/w) of C(18). The combined results of this study clearly demonstrated that the discharged energy of the thermal plume could be reused to cultivate marine alga by maintaining a relatively constant temperature in an outdoor photo-bioreactor without the need for supplying any extra energy, which could allow for cheap production of biodiesel from waste energy.

  18. 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

  19. Effects of sodium pentaborate pentahydrate exposure on Chlorella vulgaris growth, chlorophyll content, and enzyme activities.

    PubMed

    Chen, Xueqing; Pei, Yuansheng

    2016-10-01

    Sodium pentaborate pentahydrate (SPP) is a rare mineral. In this study, SPP was synthesized from boric acid and borax through low-temperature crystallization, and its effects on the growth of the alga, Chlorella vulgaris (C. vulgaris) were assessed. The newly synthesized SPP was characterized by chemical analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, and differential thermal analysis. The changes in C. vulgaris growth, chlorophyll content, and enzyme activities upon exposure to SPP for 168h were evaluated. Results showed that SPP treatment was detrimental to C. vulgaris growth during the first 24-120h of exposure. The harmful effects, however, diminished over time (168h), even at an effective medium concentration of 226.37mg BL(-1) (the concentration of boron applied per liter of culture medium). A similar trend was observed for chlorophyll content (chlorophyll a and b) and indicated that the photosynthesis of C. vulgaris was not affected and that high levels of SPP may even promote chlorophyll synthesis. Superoxide dismutase and catalase activities of C. vulgaris increased during 24-120h exposure to SPP, but these activities gradually decreased as culture time progressed. In other words, the initial detrimental effects of synthetic SPP on C. vulgaris were temporary and reversible. This research provides a scientific basis for applications of SPP in the environment.

  20. Transcriptome profiling of the microalga Chlorella pyrenoidosa in response to different carbon dioxide concentrations.

    PubMed

    Sun, Xue; Shen, Jia; Bai, Fengwei; Xu, Nianjun

    2016-10-01

    To enrich our knowledge of carbon dioxide (CO2)-concentrating mechanism (CCM) in eukaryotic algae, we used high-throughput sequencing to investigate the transcriptome profiling of the microalga Chlorella pyrenoidosa (Chlorophyta) response to different CO2 levels. Altogether, 53.86 million (M) and 62.10M clean short reads of 100 nucleotides (nt) were generated from this microalga cultured at 4-fold air CO2 (control) and air CO2 concentrations by Illumina sequencing. A total of 32,662 unigenes were assembled from the two pooled samples. With an E-value cut-off of 1e-5, 9590, 6782, 5954, and 9092 unigenes were annotated in NR, Gene Ontology (GO), Eukaryotic Cluster of Orthologous Groups of proteins (KOG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, respectively. After screening, 51 differentially expressed unigenes were up-regulated and 8 were down-regulated in the air CO2 group, relative to the control. The transcript levels of eight differentially expressed unigenes were validated by real-time quantitative PCR, which manifested that thioredoxin-like protein, laminin subunit beta-1, and chlorophyll a/b binding protein might be associated with the utilization of inorganic carbon at low CO2 levels.

  1. Metal distributions in complexes with Chlorella vulgaris in seawater and wastewater

    SciTech Connect

    Pascucci, P.R.; Kowalak, A.D.

    1999-10-01

    Divalent cadmium (Cd), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) simultaneous complexes with an algal biomass Chlorella vulgaris were studied for bioremediation purposes in various aqueous media: distilled-deionized water (DDIW), seawater, nuclear-reactor pool water, and process wastewater. Reactions were monitored using various dry masses of algae at constant temperature and constant metal concentrations for reaction times ranging from 0 to 150 minutes. Complexes occurred within 30 minutes and reached a steady state after 80 to 120 minutes. Distribution constants (K{prime}{sub d}) were calculated for the complexes and relative orders of K{prime}{sub d} were reported. The K{prime}{sub d} are used to evaluate relative efficiency of metal remediation from waters. Lead, Cu, and Ni complexes had the greatest K{prime}{sub d} values and those metals were most efficiently removed from these waters. Zinc and Fe formed the most labile complexes. The order of K{prime}{sub d} values for complexes in DDIW was Pb > Cu > Cd > Zn, then Cu > Cd > Zn in seawater, Cd > Cu > Zn in reactor pool water, and Ni > Cd > Cu > Zn > Fe in wastewater. C. vulgaris biomass may potentially be used as an alternative to traditional water treatment methods for simultaneous extraction of metals from seawater, process wastewater, or drinking water.

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

    PubMed

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

    2016-02-01

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

  3. Lipid accumulation and growth of Chlorella zofingiensis in flat plate photobioreactors outdoors.

    PubMed

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

    2011-11-01

    Culturing microalgae using natural sunlight is an effective way to reduce the cost of microalgae-based biodiesel production. In order to evaluate the feasibility of culturing Chlorella zofingiensis outdoors for biodiesel production, effects of nitrogen limitation and initial cell concentration on growth and lipid accumulation of this alga were investigated in 60 L flat plate photobioreactors outdoors. The highest μmax and biomass productivity obtained was 0.994 day(-1) and 58.4 mg L(-1)day(-1), respectively. The lipid content was much higher (54.5% of dry weight) under nitrogen limiting condition than under nitrogen sufficient condition (27.3%). With the increasing initial cell concentrations, the lipid contents declined, while lipid concentrations and productivities increased. The highest lipid content, lipid concentration, and lipid productivity obtained was 54.5%, 536 mg L(-1) and 22.3 mg L(-1)day(-1), respectively. This study demonstrated that it was possible to culture C. zofingiensis under outdoor conditions for producing biodiesel feedstock.

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

    PubMed

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

    2016-09-01

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

  5. Hydrothermal liquefaction of Chlorella pyrenoidosa in sub- and supercritical ethanol with heterogeneous catalysts.

    PubMed

    Zhang, Jixiang; Chen, Wan-Ting; Zhang, Peng; Luo, Zhongyang; Zhang, Yuanhui

    2013-04-01

    Hydrothermal liquefaction (HTL) of low lipid content microalgae Chlorella pyrenoidosa with heterogeneous catalysts was processed under sub- and supercritical conditions of ethanol (200-300°C, 2.8-9.0 MPa, 30 min). The HTL products were separated into bio-crude, gas, solid residue and volatile components, and then characterized. The highest mass and energy recovery ratios of bio-crude on the dry basis of alga were 71.3% and 101.8% respectively, obtained at 240°C, while the highest higher heating value of bio-crude was 36.19 MJ/kg, obtained at 300°C. Temperature was found to be the most dominant parameter. H2 as a processing gas at an initial pressure of 1.03 MPa slightly improved the bio-crude yield and quality. Raney-Ni and HZSM-5 type zeolite catalysts had no significant effect on the presented HTL process. The results indicated that HTL with ethanol as the solvent was able to produce 50-70 wt.% of bio-crude directly from C. pyrenoidosa.

  6. High quality biodiesel production from a microalga Chlorella protothecoides by heterotrophic growth in fermenters.

    PubMed

    Xu, Han; Miao, Xiaoling; Wu, Qingyu

    2006-12-01

    The aim of the study was to obtain high quality biodiesel production from a microalga Chlorella protothecoids through the technology of transesterification. The technique of metabolic controlling through heterotrophic growth of C. protothecoides was applied, and the heterotrophic C. protothecoides contained the crude lipid content of 55.2%. To increase the biomass and reduce the cost of alga, corn powder hydrolysate instead of glucose was used as organic carbon source in heterotrophic culture medium in fermenters. The result showed that cell density significantly increased under the heterotrophic condition, and the highest cell concentration reached 15.5 g L(-1). Large amount of microalgal oil was efficiently extracted from the heterotrophic cells by using n-hexane, and then transmuted into biodiesel by acidic transesterification. The biodiesel was characterized by a high heating value of 41 MJ kg(-1), a density of 0.864 kg L(-1), and a viscosity of 5.2 x 10(-4) Pa s (at 40 degrees C). The method has great potential in the industrial production of liquid fuel from microalga.

  7. Viruses of eukaryotice green algae

    SciTech Connect

    Van Etten, J.L.

    1989-01-01

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

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

    PubMed

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

    2015-05-01

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

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

    PubMed

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

    2014-12-01

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

  10. Chlorella species as hosts for genetic engineering and expression of heterologous proteins: Progress, challenge and perspective.

    PubMed

    Yang, Bo; Liu, Jin; Jiang, Yue; Chen, Feng

    2016-10-01

    The species of Chlorella represent a highly specialized group of green microalgae that can produce high levels of protein. Many Chlorella strains can grow rapidly and achieve high cell density under controlled conditions and are thus considered to be promising protein sources. Many advances in the genetic engineering of Chlorella have occurred in recent years, with significant developments in successful expression of heterologous proteins for various applications. Nevertheless, a lot of obstacles remain to be addressed, and a sophisticated and stable Chlorella expression system has yet to emerge. This review provides a brief summary of current knowledge on Chlorella and an overview of recent progress in the genetic engineering of Chlorella, and highlights the advances in the development of a genetic toolbox of Chlorella for heterologous protein expression. Research directions to further exploit the Chlorella expression system with respect to both challenges and perspectives are also discussed. This paper serves as a comprehensive literature review for the Chlorella community and will provide valuable insights into future exploration of Chlorella as a promising host for heterologous protein expression.

  11. 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.

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

    NASA Astrophysics Data System (ADS)

    Ma, Ruijuan; Lin, Xiangzhi

    2014-03-01

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2014-02-01

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

  15. The effects of pH on the growth of Chlorella vulgaris and its interactions with cadmium toxicity.

    PubMed

    Rachlin, J W; Grosso, A

    1991-05-01

    The effects of pH alone, and in combination with exposure to 0.89 microM cadmium, on the growth response of the green alga Chlorella vulgaris were evaluated. Acidic (3.0-6.2) and alkaline (8.3-9.0) pH values retarded the growth of this alga. Optimal growth occurred when the pH of the medium was adjusted to values of 7.5 and 8.0. When the cells were exposed to pH adjusted medium plus the presence of 0.89 microM Cd, a value known to reduce population growth by 50% at the control pH of 6.9, the affects were additive at the acidic (3.0-5.0) pH ranges. At alkaline pH values of 8.3-9.0 all toxicity responses could be explained by pH adjustment alone, indicating that additional cadmium toxicity was absent. At pH values of 7.5 and 8.0, cadmium toxicity was mitigated against, and resultant growth at pH 8.0 was at the same enhanced rate as this pH without cadmium.

  16. Elucidation of the defence mechanism in microalgae Chlorella sorokiniana under mercury exposure. Identification of Hg-phytochelatins.

    PubMed

    Gómez-Jacinto, Verónica; García-Barrera, Tamara; Gómez-Ariza, José Luis; Garbayo-Nores, Inés; Vílchez-Lobato, Carlos

    2015-08-05

    Algae and aquatic macrophytes are capable of accumulating heavy metals up to concentrations several orders of magnitude higher than those existing in their surrounding environment. Investigation of mercury toxicology in microalgae is of great interest from ecological point of view, since they could be used as bioindicator to evaluate aquatic ecosystems affected by Hg pollution. In this study, we have performed an exposure experiment focused on the biological response of microalgae Chlorella sorokiniana, a unicellular model organism, to Hg-induced toxicity. The culture was exposed to different concentrations of this element for nine days, namely 0.5, 1, 5 and 10mg L(-1) of HgCl2 (as Hg). To achieve a better understanding of the biological mechanisms triggered by Hg-induced toxicity in this alga a metallomic approach based on SEC-ICP-ORS-MS was applied to survey biomarkers of biological response to mercury contamination in surface water. In addition, the combination of RP-HPLC-ICP-ORS-MS and RP-HPLC-ESI-QqQ-TOF-MS was applied to identify, for the first time, two Hg-binding phytochelatins in this aquatic organism, using cell extracts from microalgae exposed to inorganic mercury.

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

    SciTech Connect

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

    1987-04-01

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

  18. Cost-effective Chlorella biomass production from dilute wastewater using a novel photosynthetic microbial fuel cell (PMFC).

    PubMed

    Ma, Jinxing; Wang, Zhiwei; Zhang, Junyao; Waite, T David; Wu, Zhichao

    2017-01-01

    While microalgae have been suggested as a promising substitute to conventional fossil fuels, their cost effective cultivation and harvesting constitutes a major challenge. In the work described here, a novel photosynthetic microbial fuel cell (PMFC) in which a stainless steel mesh with biofilm formed on it serves as both the cathode and filtration material has been developed. Results of this study reveal that, in addition to inducing oxygen reduction reactions under illumination, the biocathode is effective in preventing the washout of algae during continuous operation, resulting in retained biomass concentrations reaching 3.5-6.5 g L(-1). The maximum output current density reached ∼200 mA m(-2) under irradiation, which is comparable with recent PMFC studies. Microbial diversity analyses targeting 16S and 18S rRNA genes indicated that the eukaryotic species belonging to the genus Chlorella was able to sustain its community dominance (>96%) over other competing species over the course of the studies. In the absence of catalysts such as Pt, a consortium of photosynthetic organisms including plant growth-promoting bacteria such as Azospirillum and Rhizobium were overrepresented in the biofilm, with these organisms most likely contributing to cathodic electron transfer. Energy flow analysis suggested that the PMFC system held the potential to achieve theoretical energy balance in simultaneous algae production and wastewater treatment.

  19. 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.

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

    PubMed

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

    2014-04-15

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

  1. 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.

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

    SciTech Connect

    Baudou, A.; Ribeyre, F.

    1981-12-01

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

  3. Comparative transcriptomic analysis reveals phenol tolerance mechanism of evolved Chlorella strain.

    PubMed

    Zhou, Lin; Cheng, Dujia; Wang, Liang; Gao, Juan; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

    2017-03-01

    The growth of microalgae is inhibited by high concentration phenol due to reactive oxygen species. An evolved strain tolerated to 500mg/L phenol, Chlorella sp. L5, was obtained in previous study. In this study, comparative transcriptomic analysis was performed for Chlorella sp. L5 and its original strain (Chlorella sp. L3). The tolerance mechanism of Chlorella sp. L5 for high concentration phenol was explored on genome scale. It was identified that the up-regulations of the related genes according to antioxidant enzymes (SOD, APX, CAT and GR) and carotenoids (astaxanthin, lutein and lycopene) biosynthesis had critical roles to tolerate high concentration phenol. In addition, most of genes of PS I, PS II, photosynthetic electron transport chain and starch biosynthesis were also up-regulated. It was consistent to the experimental results of total carbohydrate contents of Chlorella sp. L3 and Chlorella sp. L5 under 0mg/L and 500mg/L phenol.

  4. STUDIES ON THE CHANGE OF THE CONCENTRATIONS OF INTERMEDIATES DURING PHOTOSYNTHESIS OF CHLORELLA AND ISOLATED CHLOROPLASTS.

    DTIC Science & Technology

    The chages in the concentrations of intermediates and the distribution of C(14) after photosynthesis in C(14)02 by Chlorella and isolated...changes in the concentrations of intermediates in Chlorella during the transition from light to dark and vice versa are independent of CO2, but...dependent on anaerobiosis. (2) In Chlorella photosynthesis is inhibited even by a concentration of monoiodoacetic acid which is 100 times lower than that

  5. 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.

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

    SciTech Connect

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

    1993-02-01

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

  7. Transgenic algae engineered for higher performance

    DOEpatents

    Unkefer, Pat J; Anderson, Penelope S; Knight, Thomas J

    2014-10-21

    The present disclosure relates to transgenic algae having increased growth characteristics, and methods of increasing growth characteristics of algae. In particular, the disclosure relates to transgenic algae comprising a glutamine phenylpyruvate transaminase transgene and to transgenic algae comprising a glutamine phenylpyruvate transaminase transgene and a glutamine synthetase.

  8. Nitric oxide and heat shock protein 90 co-regulate temperature-induced bleaching in the soft coral Eunicea fusca

    NASA Astrophysics Data System (ADS)

    Ross, Cliff

    2014-06-01

    Coral bleaching represents a complex physiological process that is affected not only by environmental conditions but by the dynamic internal cellular biology of symbiotic dinoflagellates ( Symbiodinium spp.) and their cnidarian hosts. Recently, nitric oxide (NO) has emerged as a key molecule involved with the expulsion of Symbiodinium from host cnidarian cells. However, the site of production remains under debate, and the corresponding signaling pathways within and between host and endosymbiont remain elusive. In this study, using freshly isolated Symbiodinium from the soft coral Eunicea fusca, I demonstrate that thermally induced stress causes an upregulation in Symbiodinium heat shock protein 90 (Hsp90). In turn, Hsp90 shows a concomitant ability to enhance the activity of a constitutively expressed isoform of NO synthase. The resulting production of NO constitutes a signaling molecule capable of inducing Symbiodinium expulsion. Using nitric oxide synthase (NOS) and Hsp90 polyclonal antibodies, thermal stress-induced Hsp90 was shown to co-immunoprecipitate with a constitutive isoform of NOS. The specific blocking of Hsp90 activity, with the Hsp90 inhibitor geldanamycin, was capable of inhibiting NO production implicating the involvement of a coordinated regulatory system. These results have strong evolutionary implications for Hsp90-NOS chaperone complexes among biological kingdoms and provide evidence for a new functional role in symbiotic associations.

  9. Genetic hitchhiking and resistance evolution to transgenic Bt toxins: insights from the African stalk borer Busseola fusca (Noctuidae).

    PubMed

    Campagne, P; Capdevielle-Dulac, C; Pasquet, R; Cornell, S J; Kruger, M; Silvain, J-F; LeRü, B; Van den Berg, J

    2017-04-01

    Since transgenic crops expressing Bacillus thuringiensis (Bt) toxins were first released, resistance evolution leading to failure in control of pests populations has been observed in a number of species. Field resistance of the moth Busseola fusca was acknowledged 8 years after Bt maize was introduced in South Africa. Since then, field resistance of this corn borer has been observed at several locations, raising questions about the nature, distribution and dynamics of the resistance trait. Using genetic markers, our study identified four outlier loci clearly associated with resistance. In addition, genetic structure at neutral loci reflected extensive gene flow among populations. A realistically parameterised model suggests that resistance could travel in space at speed of several kilometres a year. Markers at outlier loci delineated a geographic region associated with resistance spread. This was an area of approximately 100 km radius, including the location where resistance was first reported. Controlled crosses corroborated these findings and showed significant differences of progeny survival on Bt plants depending on the origin of the resistant parent. Last, our study suggests diverse resistance mutations, which would explain the widespread occurrence of resistant larvae in Bt fields across the main area of maize production in South Africa.

  10. Isolation and in silico analysis of a novel H+-pyrophosphatase gene orthologue from the halophytic grass Leptochloa fusca

    NASA Astrophysics Data System (ADS)

    Rauf, Muhammad; Saeed, Nasir A.; Habib, Imran; Ahmed, Moddassir; Shahzad, Khurram; Mansoor, Shahid; Ali, Rashid

    2017-02-01

    Structure prediction can provide information about function and active sites of protein which helps to design new functional proteins. H+-pyrophosphatase is transmembrane protein involved in establishing proton motive force for active transport of Na+ across membrane by Na+/H+ antiporters. A full length novel H+-pyrophosphatase gene was isolated from halophytic grass Leptochloa fusca using RT-PCR and RACE method. Full length LfVP1 gene sequence of 2292 nucleotides encodes protein of 764 amino acids. DNA and protein sequences were used for characterization using bioinformatics tools. Various important potential sites were predicted by PROSITE webserver. Primary structural analysis showed LfVP1 as stable protein and Grand average hydropathy (GRAVY) indicated that LfVP1 protein has good hydrosolubility. Secondary structure analysis showed that LfVP1 protein sequence contains significant proportion of alpha helix and random coil. Protein membrane topology suggested the presence of 14 transmembrane domains and presence of catalytic domain in TM3. Three dimensional structure from LfVP1 protein sequence also indicated the presence of 14 transmembrane domains and hydrophobicity surface model showed amino acid hydrophobicity. Ramachandran plot showed that 98% amino acid residues were predicted in the favored region.

  11. Structure and Mechanism of the Siderophore-Interacting Protein from the Fuscachelin Gene Cluster of Thermobifida fusca.

    PubMed

    Li, Kunhua; Chen, Wei-Hung; Bruner, Steven D

    2015-06-30

    Microbial iron acquisition is a complex process and frequently a key and necessary step for survival. Among the several paths for iron assimilation, small molecule siderophore-mediated transport is a commonly employed strategy of many microorganisms. The chemistry and biology of the extraordinary tight and specific binding of siderophores to metal is also exploited in therapeutic treatments for microbial virulence and metal toxicity. The intracellular fate of iron acquired via the siderophore pathway is one of the least understood steps in the complex process at the molecular level. A common route to cellular incorporation is the single-electron reduction of ferric to ferrous iron catalyzed by specific and/or nonspecific reducing agents. The biosynthetic gene clusters for siderophores often contain representatives of one or two families of redox-active enzymes: the flavin-containing "siderophore-interacting protein" and iron-sulfur ferric siderophore reductases. Here we present the structure and characterization of the siderophore-interacting protein, FscN, from the fuscachelin siderophore gene cluster of Thermobifida fusca. The structure shows a flavoreductase fold with a noncovalently bound FAD cofactor along with an unexpected metal bound adjacent to the flavin site. We demonstrated that FscN is redox-active and measured the binding and reduction of ferric fuscachelin. This work provides a structural basis for the activity of a siderophore-interacting protein and further insight into the complex and important process of iron acquisition and utilization.

  12. Timing of births in sympatric brown howler monkeys (Alouatta fusca clamitans) and northern muriquis (Brachyteles arachnoides hypoxanthus).

    PubMed

    Strier, K B; Mendes, S L; Santos, R R

    2001-10-01

    We monitored the birth patterns of sympatric brown howler monkeys (Alouatta fusca clamitans) and northern muriquis (Brachyteles arachnoides hypoxanthus) during a 4-yr period from October 1996 to August 2000 at the Estação Biológica de Caratinga, Minas Gerais, Brazil. Brown howler monkey births (n = 34) occurred throughout the year, and birth frequencies did not differ between rainy and dry season months. The aseasonal birth patterns of the howler monkeys differed significantly from the dry season concentration and dry month peak in muriqui births (n = 23). We found no effects of infant sex or the number of females on interbirth intervals (IBIs) in our 10 howler monkey study troops. IBIs of brown howler monkeys averaged 21.2 +/- 2.5 mo (n = 8, median = 21.0 mo), and were significantly shorter following dry season births than rainy season births. Their IBIs and yearling survivorship (74%) were similar to those reported for other species of howler monkeys, but yearling survivorship was much lower than that of muriquis (94%), whose IBIs were more than 12 mo longer than those of the howler monkeys. Our study extends comparative knowledge of birth patterns in Alouatta to a poorly known species, and provides insights into the different ways in which diet and life history may affect the timing of births in large-bodied platyrrhines under the same seasonal ecological conditions.

  13. Structure of Thermobifida fusca DyP-type peroxidase and activity towards Kraft lignin and lignin model compounds.

    PubMed

    Rahmanpour, Rahman; Rea, Dean; Jamshidi, Shirin; Fülöp, Vilmos; Bugg, Timothy D H

    2016-03-15

    A Dyp-type peroxidase enzyme from thermophilic cellulose degrader Thermobifida fusca (TfuDyP) was investigated for catalytic ability towards lignin oxidation. TfuDyP was characterised kinetically against a range of phenolic substrates, and a compound I reaction intermediate was observed via pre-steady state kinetic analysis at λmax 404 nm. TfuDyP showed reactivity towards Kraft lignin, and was found to oxidise a β-aryl ether lignin model compound, forming an oxidised dimer. A crystal structure of TfuDyP was determined, to 1.8 Å resolution, which was found to contain a diatomic oxygen ligand bound to the heme centre, positioned close to active site residues Asp-203 and Arg-315. The structure contains two channels providing access to the heme cofactor for organic substrates and hydrogen peroxide. Site-directed mutant D203A showed no activity towards phenolic substrates, but reduced activity towards ABTS, while mutant R315Q showed no activity towards phenolic substrates, nor ABTS.

  14. [Generalized behavior study on the growth dynamics for dominant algae species forming algal bloom in the three Gorges reservoir region].

    PubMed

    Liu, Xin-an; Feng, Li; Jia, Charles Q

    2008-08-01

    From the blue-green algae species a representative algae, namely, ChloreUlla vulgaris (CV)to belong to Chlorophyta is selected as one of algae species studied in order to investigate the effect of TN, TP on the growth behavior of CV with the Monod equation, and calculate the semi-saturation constants of CV to TP(K(SP)) and TN(K(SN)). K(SN) > K(SP) showed that the effect of TP on growth of CV is obvious significant than that of TN. The growth rate of Chlorella vulgaris is very sensitive to the concentration of phosphorus: Compares with the blank value, the special growth rate (mu) has been enhanced under the low concentration of 0.002 mg x L(-1), then the concentration turned to 0.2 mg x L(-1) the special growth rate (mu) has been enhanced obviously; but there was hardly any change under the concentration of nitrogen from 0.000 to 0.050 mg x L(-1). At the same time, in order to reveal whether there was a generalized character associating the growth dynamics of CV with that of dominant blue-green algae species, the dynamic models including CV constructed from our experimental data, dominant blue-green algae and sea algae from literature information have been compared and analyzed systemically, and the results showed that their growth dynamics behavior and ecological characteristic were extremely similar and common. According to extrapolation of the intercommunity of all growth dynamics we could describe and show availably there is a common behavior to the growth of dominant blue-green algae in the Three Gorges reservoir region. This conclusion would have some important theoretical and applied significance.

  15. Biological importance of marine algae.

    PubMed

    El Gamal, Ali A

    2010-01-01

    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.

  16. Logistic analysis of algae cultivation.

    PubMed

    Slegers, P M; Leduc, S; Wijffels, R H; van Straten, G; van Boxtel, A J B

    2015-03-01

    Energy requirements for resource transport of algae cultivation are unknown. This work describes the quantitative analysis of energy requirements for water and CO2 transport. Algae cultivation models were combined with the quantitative logistic decision model 'BeWhere' for the regions Benelux (Northwest Europe), southern France and Sahara. For photobioreactors, the energy consumed for transport of water and CO2 turns out to be a small percentage of the energy contained in the algae biomass (0.1-3.6%). For raceway ponds the share for transport is higher (0.7-38.5%). The energy consumption for transport is the lowest in the Benelux due to good availability of both water and CO2. Analysing transport logistics is still important, despite the low energy consumption for transport. The results demonstrate that resource requirements, resource distribution and availability and transport networks have a profound effect on the location choices for algae cultivation.

  17. The role of exopolymeric substances in the bioaccumulation and toxicity of Ag nanoparticles to algae

    PubMed Central

    Zhou, Kaijun; Hu, Yi; Zhang, Luqing; Yang, Kun; Lin, Daohui

    2016-01-01

    Exopolymeric substances (EPS) have an important role in bioaccumulation and toxicity of nanoparticles (NPs) to algae, which warrants specific studies. The interaction of EPS with citrate and polyvinyl pyrrolidone (PVP) coated AgNPs (C-AgNPs and P-AgNPs, respectively) and its roles in bioaccumulation and toxicity of the AgNPs to Chlorella pyrenoidosa were investigated. The amino and aromatic carboxylic groups in the EPS were involved in the EPS-AgNP interactions. Compared with Ag+, C-AgNPs had comparable total bioaccumulation but greater absorption by intact algae with EPS; P-AgNPs had the smallest total bioaccumulation and were mainly adsorbed on algal surfaces. With EPS removed, the total bioaccumulations and surface adsorptions for the three Ag species decreased but the cell internalizations increased; the 96 h half growth inhibition concentrations decreased, indicating EPS alleviated the algal toxicity of Ag. The cell-internalized but not the adsorbed AgNPs could contribute to the nanotoxicity. The EPS could bind both AgNPs and Ag+, and thus inhibited the cell internalization and the nanotoxicity. However, the EPS-bound Ag on the cell surfaces would migrate along with the algae and be biologically amplified in the aquatic food chains, presenting ecological risks. These results are helpful for understanding the fate and ecological effects of NPs. PMID:27615743

  18. The role of exopolymeric substances in the bioaccumulation and toxicity of Ag nanoparticles to algae

    NASA Astrophysics Data System (ADS)

    Zhou, Kaijun; Hu, Yi; Zhang, Luqing; Yang, Kun; Lin, Daohui

    2016-09-01

    Exopolymeric substances (EPS) have an important role in bioaccumulation and toxicity of nanoparticles (NPs) to algae, which warrants specific studies. The interaction of EPS with citrate and polyvinyl pyrrolidone (PVP) coated AgNPs (C-AgNPs and P-AgNPs, respectively) and its roles in bioaccumulation and toxicity of the AgNPs to Chlorella pyrenoidosa were investigated. The amino and aromatic carboxylic groups in the EPS were involved in the EPS-AgNP interactions. Compared with Ag+, C-AgNPs had comparable total bioaccumulation but greater absorption by intact algae with EPS; P-AgNPs had the smallest total bioaccumulation and were mainly adsorbed on algal surfaces. With EPS removed, the total bioaccumulations and surface adsorptions for the three Ag species decreased but the cell internalizations increased; the 96 h half growth inhibition concentrations decreased, indicating EPS alleviated the algal toxicity of Ag. The cell-internalized but not the adsorbed AgNPs could contribute to the nanotoxicity. The EPS could bind both AgNPs and Ag+, and thus inhibited the cell internalization and the nanotoxicity. However, the EPS-bound Ag on the cell surfaces would migrate along with the algae and be biologically amplified in the aquatic food chains, presenting ecological risks. These results are helpful for understanding the fate and ecological effects of NPs.

  19. Assimilation efficiency of organic contaminants from algae by the zebra mussel, Dreissena polymorpha

    SciTech Connect

    Goldenstein, T.A.; Bruner, K.A.; Fisher, S.W.; Landrum, P.F.

    1995-12-31

    A high percent of hydrophobic contaminants in the Great Lakes are particulate bound. Due to large populations and its high filtering capacity, the zebra mussel, Dreissena polymorpha, has the potential to re-direct contaminants from the water column by removal of contaminated particles, including algae. Throughout a season, zebra mussels feed on a variety of algal species. To determine if there are algal species differences in assimilation efficiency of contaminants, the percent assimilation efficiency (%AE) of three PCB congeners and DDE from three algae species were investigated using pulse-chase methodology. Results suggest no species difference in %AE for hexachlorobiphenyl (HCBP) from the algae Chlorella vulgaris and Chlamydomonas rheinhardtii. The mean %AE of HCBP from C. vulgaris was 60.9 (SE = {+-} 4.1), as compared to 68.6 (SE = {+-} 2.9) from C. rheinhardtii. Results from additional compounds and algal species will be discussed. The results of this study will allow them to refine the mechanism of contaminant uptake in aquatic filter feeders and assess the effect of zebra mussels on contaminant cycling in the Great lakes.

  20. Microbial fuel cell with an algae-assisted cathode: A preliminary assessment

    NASA Astrophysics Data System (ADS)

    González del Campo, Araceli; Cañizares, Pablo; Rodrigo, Manuel A.; Fernández, Francisco J.; Lobato, Justo

    2013-11-01

    A microbial fuel cell (MFC) with an algae-assisted cathode, i.e., a system where the oxygen required by the cathode is not provided by aeration but by the photosynthetic process of the algae (Chlorella vulgaris), has been studied. The cathode was illuminated for 12 h each day (from 8:00 h to 20:00 h). 25 days was necessary to achieve steady state conditions. The time evolution of dissolved oxygen and cell voltage were assessed over the course of each day. As expected, the dissolved oxygen values were not constant throughout the day, reaching maximum values between 14:00 h and 20:00 h when dark phase reactions began and the algae started to consume oxygen. Cell voltage (Rext 120 Ω) followed the same trend as the oxygen profile. The supply of CO2 in the cathode was also studied, and half an hour was enough time to get the system working properly. During the acclimation stage, power density increased up to 13.5 mW m-2 at steady state conditions. However, impedance analysis showed that polarization resistance was higher at the cathode than at the anode. Nevertheless, it can be concluded that the studied system is a feasible method to treat wastewater in a self-sustainable way.

  1. The role of exopolymeric substances in the bioaccumulation and toxicity of Ag nanoparticles to algae.

    PubMed

    Zhou, Kaijun; Hu, Yi; Zhang, Luqing; Yang, Kun; Lin, Daohui

    2016-09-12

    Exopolymeric substances (EPS) have an important role in bioaccumulation and toxicity of nanoparticles (NPs) to algae, which warrants specific studies. The interaction of EPS with citrate and polyvinyl pyrrolidone (PVP) coated AgNPs (C-AgNPs and P-AgNPs, respectively) and its roles in bioaccumulation and toxicity of the AgNPs to Chlorella pyrenoidosa were investigated. The amino and aromatic carboxylic groups in the EPS were involved in the EPS-AgNP interactions. Compared with Ag(+), C-AgNPs had comparable total bioaccumulation but greater absorption by intact algae with EPS; P-AgNPs had the smallest total bioaccumulation and were mainly adsorbed on algal surfaces. With EPS removed, the total bioaccumulations and surface adsorptions for the three Ag species decreased but the cell internalizations increased; the 96 h half growth inhibition concentrations decreased, indicating EPS alleviated the algal toxicity of Ag. The cell-internalized but not the adsorbed AgNPs could contribute to the nanotoxicity. The EPS could bind both AgNPs and Ag(+), and thus inhibited the cell internalization and the nanotoxicity. However, the EPS-bound Ag on the cell surfaces would migrate along with the algae and be biologically amplified in the aquatic food chains, presenting ecological risks. These results are helpful for understanding the fate and ecological effects of NPs.

  2. Mechanistic understanding toward the toxicity of graphene-family materials to freshwater algae.

    PubMed

    Zhao, Jian; Cao, Xuesong; Wang, Zhenyu; Dai, Yanhui; Xing, Baoshan

    2017-03-15

    We systematically investigated the toxicity mechanism of three graphene-family materials (GFMs), graphene oxide (GO), reduced graphene oxide (rGO) and multi-layer graphene (MG), to algae (Chlorella pyrenoidosa). GFMs exhibited much higher toxicity than other carbon materials (carbon nanotube and graphite), with the 96 h median effective concentration (EC50) values of 37.3 (GO), 34.0 (rGO), and 62.2 (MG) mg/L. Shading effect contributed approximately 16.4% of growth inhibition by GO due to its higher dispersibility and transformation while the other GFMs did not show any shading effect. Hydrophobic rGO and MG more readily heteroagglomerated with algae than GO, thus likely leading to more direct contacts with algae. Flow cytometry results showed significant decrease of membrane integrity after GFM exposure, and rGO caused the highest membrane damage, which was confirmed by the increased DNA and K(+) efflux. The observed membrane damage was caused by a combination of oxidative stress and physical penetration/extraction. Moreover, all the three GFMs could adsorb macronutrients (N, P, Mg, and Ca) from the algal medium, thus leading to nutrient depletion-induced indirect toxicity. GO showed the highest nutrient depletion (53% of total toxicity) due to its abundant functional groups. The information provided in this work will be useful for understanding toxicity mechanism and environmental risk of different GFMs in aquatic environments.

  3. 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.

  4. Microfiltration for separation of green algae from water.

    PubMed

    Hung, M T; Liu, J C

    2006-08-15

    Cross-flow microfiltration was used for separation of green algae, Chlorella sp., from freshwater. The transmembrane pressure (TMP) was adjusted at 40, 50 and 60 kPa, respectively. The cross-flow velocity was set at 0.43 m/s for laminar flow and 0.84 m/s for turbulent flow, respectively. The results showed that flux increased as TMP increased from 40 to 50 kPa. But drastic flux decline was observed when operating at TMP of 60 kPa. Raising cross-flow velocity increased the initial flux of MF under TMP of 60 kPa. Nevertheless, implementing turbulent cross-flow did not improve the drastic flux decline under the highest TMP. Preozonation increased the dissolved organic carbon, decreased algal viability and made the size of algal cells smaller. It also increased dissolved polysaccharide that derived from extracellular organic matter (EOM). Different effects of preozonation on flux behavior of MF were observed when utilizing hydrophobic and hydrophilic membrane. Generally speaking, preozonation improved performance of microfiltration by reducing cake compressibility and the biomass loading when both membranes were used. However, dissolved polysaccharide released during preozonation was adsorbed onto the hydrophobic membrane. Consequently, fouling resistance of the hydrophobic membrane became higher. These arguments were verified by classification of hydrodynamic resistances.

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

    PubMed Central

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

    1978-01-01

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

  6. Energetic metabolism response in algae and higher plant species from simulation experiments with the clinostat

    NASA Astrophysics Data System (ADS)

    Vasilenko, A.; Popova, A. F.

    Adenylate state is acknowledged to be among the most convenient approaches in the study of physiological changes in plant cells under simulation of altered gravity condition with the clinostat. Adenylate levels and the ATP/ADP ratio in cytoplasmic and mitochondrial extracts of cultivated cells of Haplopappus gracilis and algae cells of Chlorella vulgaris under initial stages of the fast-rotating and slow-rotating clinorotation, as well as the long-term clinorotation, have been investigated. For analysis of ATP and ADP levels in the plant cells under the clinorotation, we applied a high-sensitive bioluminescence method using the luciferase and piruvate kinase enzyme systems. It has been shown that the adenylate ratio is already increased during at the start of clinorotation with the different speed of rotation in the biological material tested. The considerable changes in mitochondrial ultrastructure of Chlorella cells, as well as the rising ATP level and dropping of the ATP/ADP ratio appear after long-duration clinorotation if compared to control material. It is probably connected with the distinctions in ATP-synthetase functioning in mitochondria of the cells under the clinorotation conditions.

  7. Crystallization and preliminary X-ray diffraction analysis of the homing endonuclease I-CvuI from Chlorella vulgaris in complex with its target DNA

    PubMed Central

    Redondo, Pilar; Merino, Nekane; Villate, Maider; Blanco, Francisco J.; Montoya, Guillermo; Molina, Rafael

    2014-01-01

    Homing endonucleases are highly specific DNA-cleaving enzymes that recognize long stretches of DNA. The engineering of these enzymes provides novel instruments for genome modification in a wide range of fields, including gene targeting, by inducing specific double-strand breaks. I-CvuI is a homing endonuclease from the green alga Chlorella vulgaris. This enzyme was purified after overexpression in Escherichia coli. Crystallization experiments of I-CvuI in complex with its DNA target in the presence of Mg2+ yielded crystals suitable for X-ray diffraction analysis. The crystals belonged to the orthorhombic space group P212121, with unit-cell parameters a = 62.83, b = 83.56, c = 94.40 Å. The self-rotation function and the Matthews coefficient suggested the presence of one protein–DNA complex per asymmetric unit. The crystals diffracted to a resolution limit of 1.9 Å using synchrotron radiation. PMID:24637769

  8. Viruses of eukaryotic green algae; Progress report, June 20, 1990--July 1, 1991

    SciTech Connect

    Van Etten, J.L.

    1991-12-31

    Many large polyhedral, dsDNA containing (ca. 330 kb), plaque forming viruses which infect a unicellular, eukaryotic, chlorella-like green alga have been isolated and characterized. The plaque assay, the ability to synchronously infect the host, the short life cycle, and the ability of the viruses to undergo homologous recombination make them excellent model systems for studying many plant cell functions in the manner that bacterial and animal viruses have been used to study bacterial and animal cell functions. These viruses have several unique features including: (1) coding for DNA methyltransferase and site-specific (restriction) endonucleases and (2) unlike other viruses, these viruses appear to code for the enzymes involved in the glycosylation of their glycoproteins.

  9. [Toxicity effects of Rac- and S-metolachlor on two algaes].

    PubMed

    Cai, Wei-Dan; Liu, Hui-Jun; Fang, Zhi-Guo

    2012-02-01

    The enantioselective toxicity of the chiral herbicides Rac- and S-metolachlor to Scenedesmus obliquus and Chlorella vulgaris was determined, and the effect of humic acid was studied by using acute toxicity testing method. The results indicated that the toxicity of Rac- and S-metolachlor increased with increasing concentration and exposure time. The EC(50, 96 h) ratio of Rac-metolachlor to S-metolachlor was 2.25 for C. vulgaris and 1.81 for S. obliquus, indicating that S-metolachlor had higher effect on two algaes, and S. obliquus was more sensitive to Rac- and S-metolachlor. Linear correlation between toxicity on S. obliquus and C. vulgaris was observed. The toxicity of Rac- and S-metolachlor changed with humic acid, with more significant change was observed in S-metolachlor (P<0.05).

  10. Rheological properties of algae slurries for minimizing harvesting energy requirements in biofuel production.

    PubMed

    Wileman, Angel; Ozkan, Altan; Berberoglu, Halil

    2012-01-01

    Rheological properties of microalgae slurries were measured as a function of biomass concentration from 0.5 to 80 kg/m(3) for Nannochloris sp., Chlorella vulgaris, and Phaeodactylum tricornutum. At biomass concentrations smaller than 20 kg/m(3), all slurries displayed a Newtonian fluid behavior with less than 30% increase in the effective viscosity from that of the nutrient medium. However, at biomass concentrations larger than 60 kg/m(3), the slurries of the green algae, Nannochloris sp. and C. vulgaris, displayed a shear thinning non-Newtonian behavior with varying degrees of sensitivity to shear rate while that of the diatom, P. tricornutum, was still a Newtonian fluid up to 80 kg/m(3). Moreover, bioenergy pumping effectiveness showed significant deviation among different species in the non-Newtonian regime. Finally, dewatering the slurries to concentration factors larger than 80 did not further increase the total bioenergy harvest effectiveness.

  11. Cloning of the Thermomonospora fusca Endoglucanase E2 Gene in Streptomyces lividans: Affinity Purification and Functional Domains of the Cloned Gene Product

    PubMed Central

    Ghangas, Gurdev S.; Wilson, David B.

    1988-01-01

    Thermomonospora fusca YX grown in the presence of cellulose produces a number of β-1-4-endoglucanases, some of which bind to microcrystalline cellulose. By using a multicopy plasmid, pIJ702, a gene coding for one of these enzymes (E2) was cloned into Streptomyces lividans and then mobilized into both Escherichia coli and Streptomyces albus. The gene was localized to a 1.6-kilobase PvuII-ClaI segment of the originally cloned 3.0-kilobase SstI fragment of Thermomonospora DNA. The culture supernatants of Streptomyces transformants contain a major endoglucanase that cross-reacts with antibody against Thermomonospora cellulase E2 and has the same molecular weight (43,000) as T. fusca E2. This protein binds quickly and tightly to Avicel, from which it can be eluted with guanidine hydrochloride but not with water. It also binds to filter paper but at a slower rate than to Avicel. Several large proteolytic degradation products of this enzyme generated in vivo lose the ability to bind to Avicel and have higher activity on carboxymethyl cellulose than the native enzyme. Other smaller products bind to Avicel but lack activity. A weak cellobiose-binding site not observed in the native enzyme was present in one of the degradation products. In E. coli, the cloned gene produced a cellulase that also binds tightly to Avicel but appeared to be slightly larger than T. fusca E2. The activity of intact E2 from all organisms can be inactivated by Hg2+ ions. Dithiothreitol protected against Hg2+ inactivation and reactivated both unbound and Avicel-bound Hg2+-inhibited E2, but at different rates. Images PMID:16347759

  12. Resistance of Bt-maize (MON810) against the stem borers Busseola fusca (Fuller) and Chilo partellus (Swinhoe) and its yield performance in Kenya.

    PubMed

    Tefera, Tadele; Mugo, Stephen; Mwimali, Murenga; Anani, Bruce; Tende, Regina; Beyene, Yoseph; Gichuki, Simon; Oikeh, Sylvester O; Nang'ayo, Francis; Okeno, James; Njeru, Evans; Pillay, Kiru; Meisel, Barbara; Prasanna, B M

    2016-11-01

    A study was conducted to assess the performance of maize hybrids with Bt event MON810 (Bt-hybrids) against the maize stem borer Busseola fusca (Fuller) in a biosafety greenhouse (BGH) and against the spotted stem borer Chilo partellus (Swinhoe) under confined field trials (CFT) in Kenya for three seasons during 2013-2014. The study comprised 14 non-commercialized hybrids (seven pairs of near-isogenic Bt and non-Bt hybrids) and four non-Bt commercial hybrids. Each plant was artificially infested twice with 10 first instar larvae. In CFT, plants were infested with C. partellus 14 and 24 days after planting; in BGH, plants were infested with B. fusca 21 and 31 days after planting. In CFT, the seven Bt hybrids significantly differed from their non-Bt counterparts for leaf damage, number of exit holes, percent tunnel length, and grain yield. When averaged over three seasons, Bt-hybrids gave the highest grain yield (9.7 t ha(-1)), followed by non-Bt hybrids (6.9 t ha(-1)) and commercial checks (6 t ha(-1)). Bt-hybrids had the least number of exit holes and percent tunnel length in all the seasons as compared to the non-Bt hybrids and commercial checks. In BGH trials, Bt-hybrids consistently suffered less leaf damage than their non-Bt near isolines. The study demonstrated that MON810 was effective in controlling B. fusca and C. partellus. Bt-maize, therefore, has great potential to reduce the risk of maize grain losses in Africa due to stem borers, and will enable the smallholder farmers to produce high-quality grain with increased yield, reduced insecticide inputs, and improved food security.

  13. Winter weeds as inoculum sources of tomato spotted wilt virus and as reservoirs for its vector, Frankliniella fusca (Thysanoptera: Thripidae) in farmscapes of Georgia.

    PubMed

    Srinivasan, Rajagopalbabu; Riley, David; Diffie, Stan; Shrestha, Anita; Culbreath, Albert

    2014-04-01

    Thrips-transmitted Tomato spotted wilt virus (TSWV) has a broad host range including crops and weeds. In Georgia, TSWV is known to consistently affect peanut, tomato, pepper, and tobacco production. These crops are grown from March through November. In the crop-free period, weeds are presumed to serve as a green bridge for thrips and TSWV. Previous studies have identified several winter weeds as TSWV and thrips hosts. However, their ability to influence TSWV transmission in crops is still not completely understood. To further understand these interactions, population dynamics of two prevalent vectors, viz., Frankliniella fusca (Hinds) and Frankliniella occidentalis (Pergande), on selected winter weeds were monitored from October through April in four counties from 2004 to 2008. Peak populations were typically recorded in March. F. fusca and F. occidentalis adults were found on winter weeds and their percentages ranged from 0 to 68% in comparison with other adults. Immatures outnumbered all adults. Microcosm experiments indicated that the selected winter weeds differentially supported F. fusca reproduction and development. The time required to complete one generation (adult to adult) ranged from 11 to 16 d. Adult recovery ranged from 0.97 to 2.2 per female released. In addition, transmission assays revealed that thrips efficiently transmitted TSWV from peanut to weeds, the incidence of infection ranged from 10 to 55%. Back transmission assays with thrips from TSWV-infected weeds resulted in up to 75% TSWV infection in peanut. These whole-plant transmission and back transmission assays provide the basis for TSWV persistence in farmscapes year round.

  14. Driving carbon flux through exogenous butyryl-CoA: Acetate CoA-transferase to produce butyric acid at high titer in Thermobifida fusca.

    PubMed

    Deng, Yu; Mao, Yin; Zhang, Xiaojuan

    2015-12-20

    Butyric acid, a 4-carbon short chain fatty acid, is widely used in chemical, food, and pharmaceutical industries. The low activity of butyryl-CoA: acetate CoA-transferase in Thermobifida fusca muS, a thermophilic actinobacterium whose optimal temperature was 55°C, was found to hinder the accumulation of high yield of butyric acid. In order to solve this problem, an exogenous butyryl-CoA: acetate CoA-transferase gene (actA) from Thermoanaerobacterium thermosaccharolyticum DSM571 was integrated into the chromosome of T. fusca muS by replacing celR gene, forming T. fusca muS-1. We demonstrated that on 5g/L cellulose, the yield of butyric acid by the engineered muS-1 strain was increased by 42.9 % compared to the muS strain. On 100g/L of cellulose, the muS-1 strain could consume 90.5% of total cellulose in 144h, with 33.2g/L butyric acid produced. Furthermore, on the mix substrates including the major components of biomass: cellulose, xylose, mannose and galactose, 70.4g/L butyric acid was produced in 168h by fed-batch fermentation. To validate the ability of fermenting biomass, the muS-1 strain was grown on the milled corn stover ranging from 200 to 250μm. The muS-1 strain had the highest butyrate titer 17.1g/L on 90g/L corn stover.

  15. Cloning of the Thermomonospora fusca Endoglucanase E2 gene in Streptomyces lividans: Affinity purification and functional domains of the cloned gene product

    SciTech Connect

    Ghangas, G.S.; Wilson, D.B. )

    1988-10-01

    Thermomonospora fusca YX grown in the presence of cellulose produces a number of {beta}-1-4-endoglucanases, some of which bind to microcrystalline cellulose. By using a multicopy plasmid, pIJ702, a gene coding for one of these enzymes (E2) was cloned into Streptomyces lividans and then mobilized into both Escherichia coli and Streptomyces albus. The gene was localized to a 1.6-kilobase PvuII-ClaI segment of the originally cloned 3.0-kilobase SstI fragment of Thermomonospora DNA. The culture supernatants of Streptomyces transformants contain a major endoglucanase that cross-reacts with antibody against Thermomonospora cellulase E2 and has the same molecular weight (43,000) as T. fusca E2. This protein binds quickly and tightly to Avicel. It also binds to filter paper but at a slower rate than to Avicel. Several large proteolytic degradation products of this enzyme generated in vivo lose the ability to bind to Avicel and have higher activity on carboxymethyl cellulose than the native enzyme. Other smaller products bind to Avicel but lack activity. A weak cellobiose-binding site not observed in the native enzyme was present in one of the degradation products. In E. coli, the cloned gene produced a cellulase that also binds tightly to Avicel but appeared to be slightly larger than T. fusca E2. The activity of intact E2 from all organisms can be inactivated by Hg{sup 2+} ions. Dithiothreitol protected against Hg{sup 2+} inactivation and reactivated both unbound and Avicel-bound Hg{sub 2+}-inhibited E2, but at different rates.

  16. Sorption kinetics and equilibrium of the herbicide diuron to carbon nanotubes or soot in absence and presence of algae.

    PubMed

    Schwab, Fabienne; Camenzuli, Louise; Knauer, Katja; Nowack, Bernd; Magrez, Arnaud; Sigg, Laura; Bucheli, Thomas D

    2014-09-01

    Carbon nanotubes (CNT) are strong sorbents for organic micropollutants, but changing environmental conditions may alter the distribution and bioavailability of the sorbed substances. Therefore, we investigated the effect of green algae (Chlorella vulgaris) on sorption of a model pollutant (diuron, synonyms: 3-(3,4-Dichlorophenyl)-1,1-dimethylurea, DCMU) to CNT (multi-walled purified, industrial grade, pristine, and oxidized; reference material: Diesel soot). In absence of algae, diuron sorption to CNT was fast, strong, and nonlinear (Freundlich coefficients: 10(5.79)-10(6.24) μg/kgCNT·(μg/L)(-n) and 0.62-0.70 for KF and n, respectively). Adding algae to equilibrated diuron-CNT mixtures led to 15-20% (median) diuron re-dissolution. The relatively high amorphous carbon content slowed down ad-/desorption to/from the high energy sorption sites for both industrial grade CNT and soot. The results suggest that diuron binds readily, but - particularly in presence of algae - partially reversibly to CNT, which is of relevance for environmental exposure and risk assessment.

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

    PubMed

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

    2015-01-01

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

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

    DOE PAGES

    Bell, Tisza A.S.; Prithiviraj, Bharath; Wahlen, Brad D.; ...

    2016-01-07

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

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

    PubMed Central

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

    2016-01-01

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

  1. Biological CO2 fixation using Chlorella vulgaris and its thermal characteristics through thermogravimetric analysis.

    PubMed

    Razzak, Shaikh A; Ali, Saad Aldin M; Hossain, Mohammad M; Mouanda, Alexis Nzila

    2016-11-01

    The present research is focused on cultivation of microalgae strain Chlorella vulgaris for bio-fixation of CO2 coupled with biomass production. In this regard, a single semi-batch vertical tubular photobioreactor and four similar photobioreactors in series have been employed. The concentration of CO2 in the feed stream was varied from 2 to 12 % (v/v) by adjusting CO2 to air ratio. The amount of CO2 capture and algae growth were monitored by measuring decrease of CO2 concentration in the gas phase, microalgal cell density, and algal biomass production rate. The results show that 4 % CO2 gives maximum amount of biomass (0.9 g L(-1)) and productivity (0.118 g L(-1) day(-1)) of C. vulgaris in a single reactor. In series reactors, average productivity per reactor found to be 0.078 g L(-1) day(-1). The maximum CO2 uptake for single reactor also found with 4 % CO2, and it is around 0.2 g L(-1) day(-1). In series reactors, average CO2 uptake is 0.13 g L(-1) day(-1) per reactor. TOC analysis shows that the carbon content of the produced biomass is around 40.67 % of total weight. The thermochemical characteristics of the cultivated C. vulgaris samples were analyzed in the presence of air. All samples burn above 200 °C and the combustion rate become faster at around 600 °C. Almost 98 wt% of the produced biomass is combustible in this range.

  2. CO2 Biofixation and Growth Kinetics of Chlorella vulgaris and Nannochloropsis gaditana.

    PubMed

    Adamczyk, Michał; Lasek, Janusz; Skawińska, Agnieszka

    2016-08-01

    CO2 biofixation was investigated using tubular bioreactors (15 and 1.5 l) either in the presence of green algae Chlorella vulgaris or Nannochloropsis gaditana. The cultivation was carried out in the following conditions: temperature of 25 °C, inlet-CO2 of 4 and 8 vol%, and artificial light enhancing photosynthesis. Higher biofixation were observed in 8 vol% CO2 concentration for both microalgae cultures than in 4 vol%. Characteristic process parameters such as productivity, CO2 fixation, and kinetic rate coefficient were determined and discussed. Simplified and advanced methods for determination of CO2 fixation were compared. In a simplified method, it is assumed that 1 kg of produced biomass equals 1.88 kg recycled CO2. Advance method is based on empirical results of the present study (formula with carbon content in biomass). It was observed that application of the simplified method can generate large errors, especially if the biomass contains a relatively low amount of carbon. N. gaditana is the recommended species for CO2 removal due to a high biofixation rate-more than 1.7 g/l/day. On day 10 of cultivation, the cell concentration was more than 1.7 × 10(7) cells/ml. In the case of C. vulgaris, the maximal biofixation rate and cell concentration did not exceed 1.4 g/l/day and 1.3 × 10(7) cells/ml, respectively.

  3. Identification of Direct Targets of FUSCA3, a Key Regulator of Arabidopsis Seed Development1[C][W][OA

    PubMed Central

    Wang, Fangfang; Perry, Sharyn E.

    2013-01-01

    FUSCA3 (FUS3) is a B3 domain transcription factor that is a member of the LEAFY COTYLEDON (LEC) group of genes. The LEC genes encode proteins that also include LEC2, a B3 domain factor related to FUS3, and LEC1, a CCAAT box-binding factor. LEC1, LEC2, and FUS3 are essential for plant embryo development. All three loss-of-function mutants in Arabidopsis (Arabidopsis thaliana) prematurely exit embryogenesis and enter seedling developmental programs. When ectopically expressed, these genes promote embryo programs in seedlings. We report on chromatin immunoprecipitation-tiling array experiments to globally map binding sites for FUS3 that, along with other published work to assess transcriptomes in response to FUS3, allow us to determine direct from indirect targets. Many transcription factors associated with embryogenesis are direct targets of FUS3, as are genes involved in the seed maturation program. FUS3 regulates genes encoding microRNAs that, in turn, control transcripts encoding transcription factors involved in developmental phase changes. Examination of direct targets of FUS3 reveals that FUS3 acts primarily or exclusively as a transcriptional activator. Regulation of microRNA-encoding genes is one mechanism by which FUS3 may repress indirect target genes. FUS3 also directly up-regulates VP1/ABI3-LIKE1 (VAL1), encoding a B3 domain protein that functions as a repressor of transcription. VAL1, along with VAL2 and VAL3, is involved in the transition from embryo to seedling development. Many genes are responsive to FUS3 and to VAL1/VAL2 but with opposite regulatory consequences. The emerging picture is one of complex cross talk and interactions among embryo transcription factors and their target genes. PMID:23314941

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

    PubMed

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

    2014-04-01

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

  5. Identification of aquatically available carbon from algae through solution-state NMR of whole (13)C-labelled cells.

    PubMed

    Akhter, Mohammad; Dutta Majumdar, Rudraksha; Fortier-McGill, Blythe; Soong, Ronald; Liaghati-Mobarhan, Yalda; Simpson, Myrna; Arhonditsis, George; Schmidt, Sebastian; Heumann, Hermann; Simpson, André J

    2016-06-01

    Green algae and cyanobacteria are primary producers with profound impact on food web functioning. Both represent key carbon sources and sinks in the aquatic environment, helping modulate the dissolved organic matter balance and representing a potential biofuel source. Underlying the impact of algae and cyanobacteria on an ecosystem level is their molecular composition. Herein, intact (13)C-labelled whole cell suspensions of Chlamydomonas reinhardtii, Chlorella vulgaris and Synechocystis were studied using a variety of 1D and 2D (1)H/(13)C solution-state nuclear magnetic resonance (NMR) spectroscopic experiments. Solution-state NMR spectroscopy of whole cell suspensions is particularly relevant as it identifies species that are mobile (dissolved or dynamic gels), 'aquatically available' and directly contribute to the aquatic carbon pool upon lysis, death or become a readily available food source on consumption. In this study, a wide range of metabolites and structural components were identified within the whole cell suspensions. In addition, significant differences in the lipid/triacylglyceride (TAG) content of green algae and cyanobacteria were confirmed. Mobile species in algae are quite different from those in abundance in 'classic' dissolved organic matter (DOM) indicating that if algae are major contributors to DOM, considerable selective preservation of minor components (e.g. sterols) or biotransformation would have to occur. Identifying the metabolites and dissolved components within algal cells by NMR permits future studies of carbon transfer between species and through the food chain, whilst providing a foundation to better understand the role of algae in the formation of DOM and the sequestration/transformation of carbon in aquatic environments.

  6. 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.

  7. 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

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

    PubMed

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

    2016-02-01

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

  9. Evolutionary Significance of an Algal Gene Encoding an [FeFe]-Hydrogenase with F-Domain Homology and Hydrogenase Activity in Chlorella Variabilis NC64A

    SciTech Connect

    Meuser, J. E.; Boyd, E. S.; Ananyev, G.; Karns, D.; Radakovits, R.; Murthy, U. M. N.; Ghirardi, M. L.; Dismukes, G. C.; Peters, J. W.; Posewitz, M. C.

    2011-10-01

    [FeFe]-hydrogenases (HYDA) link the production of molecular H{sub 2} to anaerobic metabolism in many green algae. Similar to Chlamydomonas reinhardtii, Chlorella variabilis NC64A (Trebouxiophyceae, Chlorophyta) exhibits [FeFe]-hydrogenase (HYDA) activity during anoxia. In contrast to C. reinhardtii and other chlorophycean algae, which contain hydrogenases with only the HYDA active site (H-cluster), C. variabilis NC64A is the only known green alga containing HYDA genes encoding accessory FeS cluster-binding domains (F-cluster). cDNA sequencing confirmed the presence of F-cluster HYDA1 mRNA transcripts, and identified deviations from the in silico splicing models. We show that HYDA activity in C. variabilis NC64A is coupled to anoxic photosynthetic electron transport (PSII linked, as well as PSII-independent) and dark fermentation. We also show that the in vivo H{sub 2}-photoproduction activity observed is as O2 sensitive as in C. reinhardtii. The two C. variabilis NC64A HYDA sequences are similar to homologs found in more deeply branching bacteria (Thermotogales), diatoms, and heterotrophic flagellates, suggesting that an F-cluster HYDA is the ancestral enzyme in algae. Phylogenetic analysis indicates that the algal HYDA H-cluster domains are monophyletic, suggesting that they share a common origin, and evolved from a single ancestral F-cluster HYDA. Furthermore, phylogenetic reconstruction indicates that the multiple algal HYDA paralogs are the result of gene duplication events that occurred independently within each algal lineage. Collectively, comparative genomic, physiological, and phylogenetic analyses of the C. variabilis NC64A hydrogenase has provided new insights into the molecular evolution and diversity of algal [FeFe]-hydrogenases.

  10. 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)

  11. 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.

  12. Bacterial cellulose production by Komagataeibacter hansenii using algae-based glucose.

    PubMed

    Uzyol, Huma Kurtoglu; Saçan, Melek Türker

    2017-04-01

    Bacterial cellulose (BC) is a homopolymer and it is distinguished from plant-based cellulose by its unique properties such as high purity, high crystallinity, high water-holding capacity, and good biocompatibility. Microalgae are unicellular, photosynthetic microorganisms and are known to have high protein, starch, and oil content. In this study, Chlorella vulgaris was evaluated as source of glucose for the production of BC. To increase the starch content of algae the effect of nutrient starvation (nitrogen and sulfur) and light deficiency were tested in a batch assay. The starch contents (%) were 5.27 ± 0.04, 7.14 ± 0.18, 5.00 ± 0.08, and 1.35 ± 0.04 for normal cultivation, nitrogen starvation, sulfur starvation, and dark cultivation conditions, respectively. The performance of enzymatic and acidic methods was compared for the starch hydrolysis. This study demonstrated for the first time that acid hydrolysate of algal starch can be used to substitute glucose in the fermentation medium of Komagataeibacter hansenii for BC production. Glucose was used as a control for BC production. BC production yields on dry weight basis were 1.104 ± 0.002 g/L and 1.202 ± 0.005 g/L from algae-based glucose and glucose, respectively. The characterization of both BCs produced from glucose and algae-based glucose was investigated by scanning electron microscopy and Fourier transform infrared spectroscopy. The results have shown that the structural characteristics of algae-based BC were comparable to those of glucose-based BC.

  13. A Lack of Parasitic Reduction in the Obligate Parasitic Green Alga Helicosporidium

    PubMed Central

    Pombert, Jean-François; Blouin, Nicolas Achille; Lane, Chris; Boucias, Drion; Keeling, Patrick J.

    2014-01-01

    The evolution of an obligate parasitic lifestyle is often associated with genomic reduction, in particular with the loss of functions associated with increasing host-dependence. This is evident in many parasites, but perhaps the most extreme transitions are from free-living autotrophic algae to obligate parasites. The best-known examples of this are the apicomplexans such as Plasmodium, which evolved from algae with red secondary plastids. However, an analogous transition also took place independently in the Helicosporidia, where an obligate parasite of animals with an intracellular infection mechanism evolved from algae with green primary plastids. We characterised the nuclear genome of Helicosporidium to compare its transition to parasitism with that of apicomplexans. The Helicosporidium genome is small and compact, even by comparison with the relatively small genomes of the closely related green algae Chlorella and Coccomyxa, but at the functional level we find almost no evidence for reduction. Nearly all ancestral metabolic functions are retained, with the single major exception of photosynthesis, and even here reduction is not complete. The great majority of genes for light-harvesting complexes, photosystems, and pigment biosynthesis have been lost, but those for other photosynthesis-related functions, such as Calvin cycle, are retained. Rather than loss of whole function categories, the predominant reductive force in the Helicosporidium genome is a contraction of gene family complexity, but even here most losses affect families associated with genome maintenance and expression, not functions associated with host-dependence. Other gene families appear to have expanded in response to parasitism, in particular chitinases, including those predicted to digest the chitinous barriers of the insect host or remodel the cell wall of Helicosporidium. Overall, the Helicosporidium genome presents a fascinating picture of the early stages of a transition from free

  14. Flash kinetics and light intensity dependence of oxygen evolution in the blue-green alga Anacystis nidulans.

    PubMed

    Ley, A C; Babcock, G T; Sauer, K

    1975-05-15

    Patterns of oxygen evolution in flashing light for the glue-green alga Anacystis nidulans are compared with those for broken spinach chloroplasts and whole cells of the green alga Chlorella pyrenoidosa. The oscillations of oxygen yield with flash number that occur in both Anacystis and Chlorella, display a greater degree of damping than do those of isolated spinach chloroplasts. The increase in damping results from a two- to threefold increase in the fraction (alpha) of reaction centers "missed" by a flash. The increase in alpha cannot be explained by non-saturing flash intensities or by the dark reduction of the oxidized intermediates formed by the flash. Anaerobic conditions markedly increase alpha in Anacystis and Chlorella but have no effect on alpha in broken spinach chloroplasts. The results signify that the mechanism of charge separation and water oxidation involved in all three orgainsms is the same, but that the pool of secondary electron acceptors between Photosystem II and Photosystem I is more reduced in the dark, in the algal cells, than in the isolated spinach chloroplasts. Oxygen evolution in flashing light for Anacystis and Chlorella show light saturation curves for the oxygen yield of the third flash (Y3) that differ markedly from those of the steady-state flashes(YS). In experiments in which all flashes are uniformly attenuated, Y3 requires nearly twice as much light as YS to reach half-saturation. Under these conditions Y3 has a sigmoidal dependence on intensity, while that of YS is hyperbolic. These differences depend on the number of flashes attenuated. When any one of the first three flashes is attenuated, the variation of Y3 with intensity resembles that of YS. When two of the first three flashes are attenuated, Y3 is intermediate in shape between the two extremes. A quantitative interpretation of these results based on the model of Kok et al. (Kik, B., Forbush, B.and McGloin, M. (1970) Photochem. Photobiol. 14, 307-321) fits the experimental

  15. Outdoor cultivation of temperature-tolerant Chlorella sorokiniana in a column photobioreactor under low power-input.

    PubMed

    Béchet, Quentin; Muñoz, Raul; Shilton, Andy; Guieysse, Benoit

    2013-01-01

    Temperature-tolerant Chlorella sorokiniana was cultivated in a 51-L column photobioreactor with a 1.1 m(2) illuminated area. The reactor was operated outdoors under tropical meteorological conditions (Singapore) without controlling temperature and the culture was mixed at a power input of 7.5 W/m(3) by sparging CO(2) -enriched air at 1.2 L/min (gas hold-up of 0.02). Biomass productivity averaged 10 ± 2.2 g/m(2) -day over six batch studies, yielding an average photosynthetic efficiency (PE) of 4.8 ± 0.5% of the total solar radiation (P = 0.05, N = 6). This demonstrates that temperature-tolerant microalgae can be cultivated at high PE under a mixing input sevenfold to ninefold lower than current operational guidelines (50-70 W/m(3)) and without the need for temperature control (the culture broth temperature reached 41 °C during operation). In this study, the PE value was determined based on the amount of solar radiation actually reaching the algae and this amount was estimated using a mathematical model fed with onsite solar irradiance data. This determination was found to be particularly sensitive to the value of the atmospheric diffusion coefficient, which generated a significant uncertainty in the PE calculation. The use of the mathematical model, however, confirmed that the vertical reactor geometry supported efficient photosynthesis by reducing the duration and intensity of photoinhibition events. The model also revealed that all three components of direct, diffuse, and reflected solar radiation were quantitatively important for the vertical column photobioreactor, accounting for 14%, 65%, and 21% of the total solar radiation reaching the culture, respectively. The accurate prediction of the discrete components of solar radiation reaching the algae as a function of climatic, geographic, and design parameters is therefore crucial to optimize the individual reactor geometry and the layout/spacing between the individual reactors in a reactor farm.

  16. Trophic transfer potential of aluminium oxide nanoparticles using representative primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia).

    PubMed

    Pakrashi, Sunandan; Dalai, Swayamprava; Chandrasekaran, Natarajan; Mukherjee, Amitava

    2014-07-01

    The transfer of nanoparticles through the food chain can lead to bioaccumulation and biomagnification resulting in a long term negative impact on the ecosystem functions. The primary objective of this study was evaluation of aluminium oxide nanoparticles transfer from primary producers to primary consumers. A simple set up consisting of a primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia) was used. Here, C. ellipsoides were exposed to the varying concentrations of the nanoparticles ranging from 20 to 120μg/mL (196 to 1176μM) for 48h and the infested algal cells were used as the feed to C. dubia. The bioaccumulation of the nanoparticles into the daphnids was noted and the biomagnification factors were computed. The exposure was noted to cause subtle alterations in the feeding behaviour of the daphnids. This might have long term consequences in the energy flow through the food chain. The reproductive behaviour of the daphnids remained unaffected upon exposure to nanoparticle infested algal feed. Distinct observations at ultra-structural scale using transmission electron microscopy provided visual evidences for the disrupted feeding behaviour upon exposure to nanoparticle treated algae. Internalization of nanoparticle like inclusion bodies in the intracellular space of algae was also detected. The findings were further substantiated by a detailed analysis of hydrodynamic stability, bioavailability and dissolution of ions from the nanoparticles over the exposure period. Altogether, the study brings out the first of its kind of observation of trophic transfer potential/behaviour of aluminium oxide nanoparticles and its probable impacts on the energy flow in the fresh water aquatic ecosystem.

  17. 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...

  18. 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...

  19. 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...

  20. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  1. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. Algae -- a poor man's HAART?

    PubMed

    Teas, Jane; Hebert, James R; Fitton, J Helen; Zimba, Paul V

    2004-01-01

    Drawing inferences from epidemiologic studies of HIV/AIDS and in vivo and in vitro HIV inhibition by algae, we propose algal consumption as one unifying characteristic of countries with anomalously low rates. HIV/AIDS incidence and prevalence in Eastern Asia ( approximately 1/10000 adults in Japan and Korea), compared to Africa ( approximately 1/10 adults), strongly suggest that differences in IV drug use and sexual behavior are insufficient to explain the 1000-fold variation. Even in Africa, AIDS/HIV rates vary. Chad has consistently reported low rates of HIV/AIDS (2-4/100). Possibly not coincidentally, most people in Japan and Korea eat seaweed daily and the Kanemba, one of the major tribal groups in Chad, eat a blue green alga (Spirulina) daily. Average daily algae consumption in Asia and Africa ranges between 1 and 2 tablespoons (3-13 g). Regular consumption of dietary algae might help prevent HIV infection and suppress viral load among those infected.

  8. 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…

  9. 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

  10. Characterization and Quantitation of Vitamin B12 Compounds in Various Chlorella Supplements.

    PubMed

    Bito, Tomohiro; Bito, Mariko; Asai, Yusuke; Takenaka, Shigeo; Yabuta, Yukinori; Tago, Kazunori; Ohnishi, Masato; Mizoguchi, Toru; Watanabe, Fumio

    2016-11-16

    Vitamin B12 was determined and characterized in 19 dried Chlorella health supplements. Vitamin contents of dried Chlorella cells varied from <0.1 μg to approximately 415 μg per 100 g of dry weight. Subsequent liquid chromatography/electrospray ionization-tandem mass spectrometry analyses showed the presence of inactive corrinoid compounds, a cobalt-free corrinoid, and 5-methoxybenzimidazolyl cyanocobamide (factor IIIm) in four and three high vitamin B12-containing Chlorella tablets, respectively. In four Chlorella tablet types with high and moderate vitamin B12 contents, the coenzyme forms of vitamin B12 5'-deoxyadenosylcobalamin (approximately 32%) and methylcobalamin (approximately 8%) were considerably present, whereas the unnaturally occurring corrinoid cyanocobalamin was present at the lowest concentrations. The species Chlorella sorokiniana (formerly Chlorella pyrenoidosa) is commonly used in dietary supplements and did not show an absolute requirement of vitamin B12 for growth despite vitamin B12 uptake from the medium being observed. In further experiments, vitamin B12-dependent methylmalonyl-CoA mutase and methionine synthase activities were detected in cell homogenates. In particular, methionine synthase activity was significantly increased following the addition of vitamin B12 to the medium. These results suggest that vitamin B12 contents of Chlorella tablets reflect the presence of vitamin B12-generating organic ingredients in the medium or the concomitant growth of vitamin B12-synthesizing bacteria under open culture conditions.

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

    NASA Astrophysics Data System (ADS)

    Pechurkin, N. S.

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

  12. Chlorella is an effective dietary source of lutein for human erythrocytes.

    PubMed

    Miyazawa, Taiki; Nakagawa, Kiyotaka; Kimura, Fumiko; Nakashima, Yuya; Maruyama, Isao; Higuchi, Ohki; Miyazawa, Teruo

    2013-01-01

    Chlorella contains a high amount of carotenoids, especially lutein, and has received attention as a possible dietary source for improving carotenoid levels in human blood. In the present study, we performed a 2-month single arm human study, and investigated the efficacy of Chlorella supplementation (9 g Chlorella/day; equivalent to 32 mg lutein/day) on lutein and other carotenoid concentrations in plasma as well as erythrocytes of 12 healthy subjects. Following Chlorella supplementation, lutein was the predominant carotenoid in erythrocytes, showing a 4-fold increase (from 14 to 54 pmol/mL packed cells). After the one month without Chlorella ingestion, erythrocyte lutein then decreased to a basal level (17 pmol/mL packed cells). Erythrocyte carotenoid (lutein, zeaxanthin, α-carotene, and β-carotene) levels were proportional to plasma carotenoid levels. The results suggest the transfer of Chlorella carotenoids, especially lutein, from plasma lipoprotein particles to the erythrocyte membrane. Chlorella intake would be effective for improving and maintaining lutein concentrations in human erythrocytes.

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

    PubMed

    Dayana Priyadharshini, S; Bakthavatsalam, A K

    2016-05-01

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

  14. Efficient Heterologous Transformation of Chlamydomonas reinhardtii npq2 Mutant with the Zeaxanthin Epoxidase Gene Isolated and Characterized from Chlorella zofingiensis

    PubMed Central

    Couso, Inmaculada; Cordero, Baldo F.; Vargas, María Ángeles; Rodríguez, Herminia

    2012-01-01

    In the violaxanthin cycle, the violaxanthin de-epoxidase and zeaxanthin epoxidase catalyze the inter-conversion between violaxanthin and zeaxanthin in both plants and green algae. The zeaxanthin epoxidase gene from the green microalga Chlorella zofingiensis (Czzep) has been isolated. This gene encodes a polypeptide of 596 amino acids. A single copy of Czzep has been found in the C. zofingiensis genome by Southern blot analysis. qPCR analysis has shown that transcript levels of Czzep were increased after zeaxanthin formation under high light conditions. The functionality of Czzep gene by heterologous genetic complementation in the Chlamydomonas mutant npq2, which lacks zeaxanthin epoxidase (ZEP) activity and accumulates zeaxanthin in all conditions, was analyzed. The Czzep gene was adequately inserted in the pSI105 vector and expressed in npq2. The positive transformants were able to efficiently convert zeaxanthin into violaxanthin, as well as to restore their maximum quantum efficiency of the PSII (Fv/Fm). These results show that Chlamydomonas can be an efficient tool for heterologous expression and metabolic engineering for biotechnological applications. PMID:23118714

  15. Photosensitized destruction of Chlorella vulgaris by Methylene Blue or Nuclear Fast Red combined with hydrogen peroxide under visible light irradiation.

    PubMed

    McCullagh, Cathy; Robertson, Peter K J

    2006-04-01

    A considerable number of investigations have started to elucidate the essential roles biological agents play in the biodeterioration of stone. Chemical biocides are becoming increasingly banned because of the environmental and health hazards associated with these toxic substances. The present study reports the photodynamic effect of Methylene Blue (MB) and Nuclear Fast Red (NFR) in the presence of hydrogen peroxide (H2O2) on the destruction of the algae Chlorella vulgaris (C. vulgaris) under irradiation with visible light. Illumination of C. vulgaris in the presence of MB or NFR combined with H2O2 results in the decomposition of both the algal species and the photosensitizer. The photodynamic effect was investigated under aerobic and anaerobic conditions. Differences in mechanism type are reported and are dependent on both the presence and the absence of oxygen. The behavior of each photosensitizer leads to a Type II mechanism and a Type I/Type II combination for MB and NFR, respectively, being concluded. This novel combination could be effective for the remediation of biofilm-colonized stone surfaces.

  16. Light attenuates lipid accumulation while enhancing cell proliferation and starch synthesis in the glucose-fed oleaginous microalga Chlorella zofingiensis

    PubMed Central

    Chen, Tianpeng; Liu, Jin; Guo, Bingbing; Ma, Xiaonian; Sun, Peipei; Liu, Bin; Chen, Feng

    2015-01-01

    The objective of this study was to investigate the effect of light on lipid and starch accumulation in the oleaginous green algae Chlorella zofingiensis supplemented with glucose. C. zofingiensis, when fed with 30 g/L glucose, synthesized lipids up to 0.531 g/g dry weight; while in the presence of light, the lipid content dropped down to 0.352 g/g dry weight. Lipid yield on glucose was 0.184 g/g glucose, 14% higher than that cultured with light. The light-mediated lipid reduction was accompanied by the down-regulation of fatty acid biosynthetic genes at the transcriptional level. Furthermore, light promoted cell proliferation, starch accumulation, and the starch yield based on glucose. Taken together, light may attenuate lipid accumulation, possibly through the inhibition of lipid biosynthetic pathway, leading to more carbon flux from glucose to starch. This study reveals the dual effects of light on the sugar-fed C. zofingiensis and provides valuable insights into the possible optimization of algal biomass and lipid production by manipulation of culture conditions. PMID:26442783

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

    PubMed

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

    2014-10-01

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

  18. Light attenuates lipid accumulation while enhancing cell proliferation and starch synthesis in the glucose-fed oleaginous microalga Chlorella zofingiensis.

    PubMed

    Chen, Tianpeng; Liu, Jin; Guo, Bingbing; Ma, Xiaonian; Sun, Peipei; Liu, Bin; Chen, Feng

    2015-10-07

    The objective of this study was to investigate the effect of light on lipid and starch accumulation in the oleaginous green algae Chlorella zofingiensis supplemented with glucose. C. zofingiensis, when fed with 30 g/L glucose, synthesized lipids up to 0.531 g/g dry weight; while in the presence of light, the lipid content dropped down to 0.352 g/g dry weight. Lipid yield on glucose was 0.184 g/g glucose, 14% higher than that cultured with light. The light-mediated lipid reduction was accompanied by the down-regulation of fatty acid biosynthetic genes at the transcriptional level. Furthermore, light promoted cell proliferation, starch accumulation, and the starch yield based on glucose. Taken together, light may attenuate lipid accumulation, possibly through the inhibition of lipid biosynthetic pathway, leading to more carbon flux from glucose to starch. This study reveals the dual effects of light on the sugar-fed C. zofingiensis and provides valuable insights into the possible optimization of algal biomass and lipid production by manipulation of culture conditions.

  19. Volatile organic compounds released from Microcystis flos-aquae under nitrogen sources and their toxic effects on Chlorella vulgaris.

    PubMed

    Xu, Qinghuan; Yang, Lin; Yang, Wangting; Bai, Yan; Hou, Ping; Zhao, Jingxian; Zhou, Lv; Zuo, Zhaojiang

    2017-01-01

    Eutrophication promotes massive growth of cyanobacteria and algal blooms, which can poison other algae and reduce biodiversity. To investigate the differences in multiple nitrogen (N) sources in eutrophicated water on the emission of volatile organic compounds (VOCs) from cyanobacteria, and their toxic effects on other algal growth, we analyzed VOCs emitted from Microcystis flos-aquae with different types and concentrations of nitrogen, and determined the effects under Normal-N and Non-N conditions on Chlorella vulgaris. M. flos-aquae released 27, 22, 20, 27, 19, 25 and 17 compounds, respectively, with NaNO3, NaNO2, NH4Cl, urea, Ser, Lys and Arg as the sole N source. With the reduction in N amount, the emission of VOCs was increased markedly, and the most VOCs were found under Non-N condition. C. vulgaris cell propagation, photosynthetic pigment and Fv/Fm declined significantly following exposure to M. flos-aquae VOCs under Non-N condition, but not under Normal-N condition. When C. vulgaris cells were treated with two terpenoids, eucalyptol and limonene, the inhibitory effects were enhanced with increasing concentrations. Therefore, multiple N sources in eutrophicated water induce different VOC emissions from cyanobacteria, and reduction in N can cause nutrient competition, which can result in emissions of more VOCs. Those VOCs released from M. flos-aquae cells under Non-N for nutrient competition can inhibit other algal growth. Among those VOCs, eucalyptol and limonene are the major toxic agents.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  1. Survey on nitrogen removal and membrane filtration characteristics of Chlorella vulgaris Beij. on treating domestic type wastewaters.

    PubMed

    Wang, Yu-Hsuan; Wu, Chuen-Mei; Wu, Wan-Lin; Chu, Ching-Ping; Chung, Yu-Jen; Liao, Chien-Sen

    2013-01-01

    The main objective of this study is to evaluate the nitrogen assimilation and filtration characteristics of Chlorella vulgaris Beij. when treating domestic wastewaters. Chlorella could assimilate organic nitrogen, ammonia and nitrate in wastewater, and the mean cell residence time (MCRT) to achieve the maximum biomass content in a bioreactor was different for each individual nitrogen source used. The experimental results showed that using nitrate as the only nitrogen source was the most favorable for biomass growth. With ammonia and nitrate coexisting in the aquatic phase, Chlorella possibly utilized ammonia first, and this was unfavorable to subsequent biomass growth. Nitrifying bacteria in wastewaters significantly affected Chlorella growth as they possibly competed with Chlorella in assimilating ammonia and nitrate in domestic wastewater. In a submerged ultrafiltration (UF) membrane module, with an initial concentration of 850 mg/L of Chlorella, the optimized flux was 0.02 m(3)/(m(2)·h), and the filtration cycle was 30 min. A 'dual membrane bioreactor (MBR)' configuration using UF membranes for Chlorella incubation was proposed. MBR1 provides an environment with long MCRT for efficient nitrification. The converted nitrate is assimilated by Chlorella in MBR2 to sustain its growth. UF permeate from MBR1 is bacteria-free and does not affect the growth of Chlorella in MBR2. MCRT of Chlorella growth is controlled by the UF membrane of MBR2, providing the flexibility to adjust variations of nitrogen composition in the wastewater.

  2. 13C-Tracer and Gas Chromatography-Mass Spectrometry Analyses Reveal Metabolic Flux Distribution in the Oleaginous Microalga Chlorella protothecoides1[C][W][OA

    PubMed Central

    Xiong, Wei; Liu, Lixia; Wu, Chao; Yang, Chen; Wu, Qingyu

    2010-01-01

    The green alga Chlorella protothecoides has received considerable attention because it accumulates neutral triacylglycerols, commonly regarded as an ideal feedstock for biodiesel production. In order to gain a better understanding of its metabolism, tracer experiments with [U-13C]/[1-13C]glucose were performed with heterotrophic growth of C. protothecoides for identifying the metabolic network topology and estimating intracellular fluxes. Gas chromatography-mass spectrometry analysis tracked the labeling patterns of protein-bound amino acids, revealing a metabolic network consisting of the glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle with inactive glyoxylate shunt. Evidence of phosphoenolpyruvate carboxylase, phosphoenolpyruvate carboxykinase, and malic enzyme activity was also obtained. It was demonstrated that the relative activity of the pentose phosphate pathway to glycolysis under nitrogen-limited environment increased, reflecting excess NADPH requirements for lipid biosynthesis. Although the growth rate and cellular oil content were significantly altered in response to nitrogen limitation, global flux distribution of C. protothecoides remained stable, exhibiting the rigidity of central carbon metabolism. In conclusion, quantitative knowledge on the metabolic flux distribution of oleaginous alga obtained in this study may be of value in designing strategies for metabolic engineering of desirable bioproducts. PMID:20720172

  3. Outdoor cultures of Chlorella pyrenoidosa in the effluent of anaerobically digested activated sludge: The effects of pH and free ammonia.

    PubMed

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

    2016-01-01

    A freshwater algae Chlorella pyrenoidosa was cultured outdoors using anaerobically digested activated sludge effluent. The effects of pH variations were evaluated. The coupled pH variations and free ammonia toxicity significantly affected the algal growth, lipids accumulation and contamination control during every season. The free ammonia toxicity at high pH levels actually inhibited the algal growth. Compared to an optimal algal growth at a pH of 5.7-6.5, biomass productivity at a high pH of 8.3-8.8 was reduced by 67.15±6.98%, 54.39±6.42% and 83.63±5.71% in the spring, fall and summer, respectively. When the pH rose above 9.1-9.6, algae were unable to grow in the wastewater. However, high pH levels reduced contamination (e.g., bacteria and microalgae grazers) and triggered lipids accumulation in algal cells. These findings suggest that pH control strategies are essential for this type of algal wastewater system, where ammonia is the dominant nitrogen source.

  4. Hyperosmosis and its combination with nutrient-limitation are novel environmental stressors for induction of triacylglycerol accumulation in cells of Chlorella kessleri

    PubMed Central

    Hirai, Kazuho; Hayashi, Taihei; Hasegawa, Yuri; Sato, Atsushi; Tsuzuki, Mikio; Sato, Norihiro

    2016-01-01

    Triacylglycerols of oleaginous algae are promising for production of food oils and biodiesel fuel. Air-drying of cells induces triacylglycerol accumulation in a freshwater green alga, Chlorella kessleri, therefore, it seems that dehydration, i.e., intracellular hyperosmosis, and/or nutrient-limitation are key stressors. We explored this possibility in liquid-culturing C. kessleri cells. Strong hyperosmosis with 0.9 M sorbitol or 0.45 M NaCl for two days caused cells to increase the triacylglycerol content in total lipids from 1.5 to 48.5 and 75.3 mol%, respectively, on a fatty acid basis, whereas nutrient-limitation caused its accumulation to 41.4 mol%. Even weak hyperosmosis with 0.3 M sorbitol or 0.15 M NaCl, when nutrient-limitation was simultaneously imposed, induced triacylglycerol accumulation to 61.9 and 65.7 mol%, respectively. Furthermore, culturing in three-fold diluted seawater, the chemical composition of which resembled that of the medium for the combinatory stress, enabled the cells to accumulate triacylglycerol up to 24.7 weight% of dry cells in only three days. Consequently, it was found that hyperosmosis is a novel stressor for triacylglycerol accumulation, and that weak hyperosmosis, together with nutrient-limitation, exerts a strong stimulating effect on triacylglycerol accumulation. A similar combinatory stress would contribute to the triacylglycerol accumulation in air-dried C. kessleri cells. PMID:27184595

  5. Hyperosmosis and its combination with nutrient-limitation are novel environmental stressors for induction of triacylglycerol accumulation in cells of Chlorella kessleri.

    PubMed

    Hirai, Kazuho; Hayashi, Taihei; Hasegawa, Yuri; Sato, Atsushi; Tsuzuki, Mikio; Sato, Norihiro

    2016-05-17

    Triacylglycerols of oleaginous algae are promising for production of food oils and biodiesel fuel. Air-drying of cells induces triacylglycerol accumulation in a freshwater green alga, Chlorella kessleri, therefore, it seems that dehydration, i.e., intracellular hyperosmosis, and/or nutrient-limitation are key stressors. We explored this possibility in liquid-culturing C. kessleri cells. Strong hyperosmosis with 0.9 M sorbitol or 0.45 M NaCl for two days caused cells to increase the triacylglycerol content in total lipids from 1.5 to 48.5 and 75.3 mol%, respectively, on a fatty acid basis, whereas nutrient-limitation caused its accumulation to 41.4 mol%. Even weak hyperosmosis with 0.3 M sorbitol or 0.15 M NaCl, when nutrient-limitation was simultaneously imposed, induced triacylglycerol accumulation to 61.9 and 65.7 mol%, respectively. Furthermore, culturing in three-fold diluted seawater, the chemical composition of which resembled that of the medium for the combinatory stress, enabled the cells to accumulate triacylglycerol up to 24.7 weight% of dry cells in only three days. Consequently, it was found that hyperosmosis is a novel stressor for triacylglycerol accumulation, and that weak hyperosmosis, together with nutrient-limitation, exerts a strong stimulating effect on triacylglycerol accumulation. A similar combinatory stress would contribute to the triacylglycerol accumulation in air-dried C. kessleri cells.

  6. Micro-Raman spectroscopy of algae: composition analysis and fluorescence background behavior.

    PubMed

    Huang, Y Y; Beal, C M; Cai, W W; Ruoff, R S; Terentjev, E M

    2010-04-01

    Preliminary feasibility studies were performed using Stokes Raman scattering for compositional analysis of algae. Two algal species, Chlorella sorokiniana (UTEX #1230) and Neochloris oleoabundans (UTEX #1185), were chosen for this study. Both species were considered to be candidates for biofuel production. Raman signals due to storage lipids (specifically triglycerides) were clearly identified in the nitrogen-starved C. sorokiniana and N. oleoabundans, but not in their healthy counterparts. On the other hand, signals resulting from the carotenoids were found to be present in all of the samples. Composition mapping was conducted in which Raman spectra were acquired from a dense sequence of locations over a small region of interest. The spectra obtained for the mapping images were filtered for the wavelengths of characteristic peaks that correspond to components of interest (i.e., triglyceride or carotenoid). The locations of the components of interest could be identified by the high intensity areas in the composition maps. Finally, the time evolution of fluorescence background was observed while acquiring Raman signals from the algae. The time dependence of fluorescence background is characterized by a general power law decay interrupted by sudden high intensity fluorescence events. The decreasing trend is likely a result of photo-bleaching of cell pigments due to prolonged intense laser exposure, while the sudden high intensity fluorescence events are not understood.

  7. Unlocking nature’s treasure-chest: screening for oleaginous algae

    PubMed Central

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

    2015-01-01

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

  8. Death by indigestion? Particle binding of contaminants by algae and dietary uptake by Daphnia

    SciTech Connect

    Taylor, G.J.; Baird, D.J.; Soares, A.M.V.M.

    1995-12-31

    Freshwater algae, as with all suspended particulate matter in the water column, exhibit a net negative charge, which results in an affinity for positively charged species, such as toxic metal cations. Such cations will readily adsorb to algal cell surfaces, particularly at low metal concentrations. Work conducted to date, with cadmium and cells of the green algae Chlorella vulgaris, has shown that there are two contrasting effects produced by the particulate adsorption of cadmium on the toxicity of the metal to Daphnia. At sub-lethal concentrations of cadmium, the ingestion of algal cells by Daphnia is inhibited, resulting in reduced growth and reproduction. Experiments comparing the effect of algal bound and free ionic forms of cadmium demonstrate that this inhibition is almost entirely due to the surface bound fraction. However, at free cadmium concentrations that are lethal to Daphnia, algal cells were found to reduce toxicity. Further studies using slow-motion video analysis of tethered animals have confirmed this, by showing that algal-bound cadmium produces a more rapid and severe feeding inhibition response than free cadmium. These results raise several questions for ecotoxicology. Does the contrasting role of algal cells in increasing toxicity at sub-lethal levels, while reducing toxicity at lethal levels call into question the common assumption that a mechanistic link exists between acute and chronic toxicity? How can this phenomenon be controlled in laboratory experiments? How will the surface binding of contaminants in the field affect the extrapolation of laboratory results to the natural environment?

  9. THEORETICAL BASIS FOR THE PRINCIPLE OF SINGLE CELLED ALGAE CULTIVATION,

    DTIC Science & Technology

    The aim of this study is to provide the basis for a mathematical approach to the principle of cultivating chlorella , which will make possible a...biological and design. The mathe matical basis for the amount of chlorella biomass as a function of the duration of its cultivation is presented.

  10. Evaluation of the metal uptake of several algae strains in a multicomponent matrix utilizing inductively coupled plasma emission spectrometry.

    PubMed

    Mahan, C A; Majidi, V; Holcombe, J A

    1989-03-15

    Three freshwater heat-killed, lyophilized blue-green algae strains have been characterized as to their ability to accumulate heavy metals with a focus on the utilization of these algae as an analytical preconcentration technique. This study examines the metal uptake in several multicomponent mixtures by using inductively coupled plasma optical emission spectrometry (ICP-OES). Six milligrams of a pure strain of algae was added to 20-mL aliquots of buffered (pH 5.5-6.5) multielement solutions containing 0.1, 0.5, 1.0, 2.0, and 4.0 mg/L of K, Mg, Ca, Fe, Sr, Co, Cu, Mn, Ni, V, Zn, As, Cd, Mo, Pb, and Se. All three algae strains exhibit relatively high adsorption affinities for Fe, Pb, and Cu, with uptake between 70 and 98% at the 4 ppm concentration level. Biosorption occurs for essentially every element with the relative affinities decreasing in the order Pb greater than Fe greater than Cu greater than Cd greater than Zn greater than Mn greater than Mo greater than Sr greater than Ni greater than V greater than Se greater than As greater than Co for Chlorella pyrenoidosa at the 4 mg/L concentration level. Although some minor differences were seen, the other algae strains (Stichococcus bacillaris and Chlamydomonas reinharti) displayed similar adsorption behavior over the concentration range studied, indicating similar cell wall binding sites. Langmuirian isotherms exhibited a minimum of two slopes over the concentration range of 0.1-4.0 mg/L, indicating the probable existence of at least two adsorption mechanisms.

  11. Response of the blood clotting system of the American horseshoe crab, Limulus polyphemus, to a novel form of lipopolysaccharide from a green alga.

    PubMed

    Conrad, Mara L; Pardy, R L; Wainwright, Norman; Child, Alice; Armstrong, Peter B

    2006-08-01

    Lipopolysaccharide (LPS, endotoxin) is a component of Gram-negative bacteria and is the principal indicator to the innate immune systems of higher animals of a Gram-negative bacterial invasion. LPS activates the blood clotting system of the American horseshoe crab, Limulus polyphemus. By stimulating blood cell degranulation, LPS triggers the release of the proteins of the clotting system from the cells, and by activating a protease cascade that converts coagulogen, a soluble zymogen, to coagulin, the structural protein of the clot, LPS triggers the production of the fibrillar coagulin blood clot. Although originally thought to be restricted to the Gram-negative bacteria and the cyanobacteria, LPS, or a very similar molecule, has recently been described from a eukaryotic green alga, Chlorella. Here we show that, like LPS from Gram-negative bacteria, the algal molecule stimulates exocytosis of the Limulus blood cell and the clotting of coagulin. The coagulin clot efficiently entraps the cells of Chlorella in a network of fibrils. Invasion and erosion of the carapace by green algae is an important cause of mortality of Limulus, and it is suggested that the cellular response to aLPS may contribute to defense against this pathogen.

  12. 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.

  13. A New Treatment Strategy for Inactivating Algae in Ballast Water Based on Multi-Trial Injections of Chlorine

    PubMed Central

    Sun, Jinyang; Wang, Junsheng; Pan, Xinxiang; Yuan, Haichao

    2015-01-01

    Ships’ ballast water can carry aquatic organisms into foreign ecosystems. In our previous studies, a concept using ion exchange membrane electrolysis to treat ballast water has been proven. In addition to other substantial approaches, a new strategy for inactivating algae is proposed based on the developed ballast water treatment system. In the new strategy, the means of multi-trial injection with small doses of electrolytic products is applied for inactivating algae. To demonstrate the performance of the new strategy, contrast experiments between new strategies and routine processes were conducted. Four algae species including Chlorella vulgaris, Platymonas subcordiformis, Prorocentrum micans and Karenia mikimotoi were chosen as samples. The different experimental parameters are studied including the injection times and doses of electrolytic products. Compared with the conventional one trial injection method, mortality rate time (MRT) and available chlorine concentration can be saved up to about 84% and 40%, respectively, under the application of the new strategy. The proposed new approach has great potential in practical ballast water treatment. Furthermore, the strategy is also helpful for deep insight of mechanism of algal tolerance. PMID:26068239

  14. Ionic liquids-based hydrolysis of Chlorella biomass for fermentable sugars.

    PubMed

    Zhou, Na; Zhang, Yimin; Gong, Xiaowu; Wang, Qinhong; Ma, Yanhe

    2012-08-01

    An ionic liquids-based chemical hydrolysis strategy was developed to obtain high-yielding soluble sugars from Chlorella biomass. Initial ionic liquids dissolution and subsequently HCl catalyzed hydrolysis could dissolve 75.34% of Chlorella biomass and release 88.02% of total sugars from Chlorella biomass. The amount of HCl loading was 7 wt.% relative to Chlorella biomass weight, which was much lower (only 14.6%) than that in HCl/MgCl(2)-catalyzed system with similar sugars release (Zhou et al., 2011). Ionic liquids in the hydrolysates were recycled and fermentable sugars were evaluated by converting to bioethanol after separated by ion-exclusion chromatography. This ionic liquids-based hydrolysis strategy showed the great potential to produce fermentable sugars from algal biomass.

  15. Cultivation of Chlorella sp. with livestock waste compost for lipid production.

    PubMed

    Zhu, L-D; Li, Z-H; Guo, D-B; Huang, F; Nugroho, Y; Xia, K

    2017-01-01

    Cultivation of microalgae Chlorella sp. with livestock waste compost as an alternative nutrient source was investigated in this present study. Five culture media with different nutrient concentrations were prepared. The characteristics of algal growth and lipid production were examined. The results showed that the specific growth rate together with biomass and lipid productivities was different among all the cultures. As the initial nutrient concentration decreased, the lipid content of Chlorella sp. increased. The variations in lipid productivity of Chlorella sp. among all the cultures were mainly due to the deviations in biomass productivity. The livestock waste compost medium with 2000mgL(-1)COD provided an optimal nutrient concentration for Chlorella sp. cultivation, where the highest productivities of biomass (288.84mgL(-1)day(-1)) and lipid (104.89mgL(-1)day(-1)) were presented.

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  17. Effects of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) on pH, net oxygen production, and respiration by algae

    USGS Publications Warehouse

    Scholefield, Ronald J.; Fredricks, Kim T.; Slaght, Karen S.; Seelye, James G.

    1999-01-01

    The lampricide 3-trifluoromethyl-4-nitrophenol (TFM) has been used in the United States and Canada for more than 35 years to control larval sea lampreys (Petromyzon marinus) in tributaries of the Great Lakes. Occasionally, during stream treatments with TFM, nontarget-fish mortality reaches unacceptable levels. These losses could be due to the presence of sensitive fish species, excess TFM, or a combination of factors that influence the toxicity of TFM, such as delays in daily stream reaeration by algae resulting in extended periods of low pH and low dissolved oxygen (DO). We determined the effects of a broad range of TFM concentrations on net DO production and respiration by two species of algae, in two culture media (high alkalinity and low alkalinity). The pH and DO in cultures of Chlorella pyrenoidosa and Selenastrum capricornutum were recorded at time zero and again after a 9-h exposure to TFM under either lighted or dark conditions. Algal cultures exposed to TFM concentrations typical of those used to control sea lampreys in streams showed only small changes in pH (<0.1) and small reductions in DO (about 8% in lighted conditions and 11% in dark conditions). Changes in pH and DO of this magnitude probably do not change the efficacy of TFM or cause nontarget fish mortality if algae are the predominant photosynthetic organisms in the stream.

  18. 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

  19. 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

  20. Synthetic polyester from algae oil.

    PubMed

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

    2014-06-23

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

  1. Halogenated compounds from marine algae.

    PubMed

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

    2010-08-09

    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.

  2. Bioaccumulation of nickel by algae

    SciTech Connect

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

    1984-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

  4. Bioinspired, cytocompatible mineralization of silica-titania composites: thermoprotective nanoshell formation for individual chlorella cells.

    PubMed

    Ko, Eun Hyea; Yoon, Yeonjung; Park, Ji Hun; Yang, Sung Ho; Hong, Daewha; Lee, Kyung-Bok; Shon, Hyun Kyong; Lee, Tae Geol; Choi, Insung S

    2013-11-18

    Hard-shell case: Using a (RKK)4 D8 peptide allows mineralization to occur under cytocompatible conditions. Thus individual Chlorella cells could be encapsulated within a SiO2 -TiO2 nanoshell with high cell viability (87 %). The encapsulated Chlorella showed an almost threefold increase in their thermo-tolerance after 2 h at 45 °C.

  5. Removal of Nitrogen and Phosphorus From Reject Water Using Chlorella vulgaris Algae After Partial Nitrification/Anammox Process.

    PubMed

    Gutwinski, Piotr; Cema, Grzegorz

    2016-01-01

    Wastewater containing nutrients like ammonia, nitrite, nitrate and phosphates have been identified as the main cause of eutrophication in natural waters. Therefore, a suitable treatment is needed. In classical biological processes, nitrogen and phosphorus removal is expensive, especially due to the lack of biodegradable carbon, thus new methods are investigated. In this paper, the new possibility of nitrogen and phosphorus removal in side stream after the partial nitrification/Anammox process is proposed. Research was carried out in a lab-scale vertical tubular photobioreactor (VTR) fed with real reject water, from dewatering of digested sludge, after partial nitrification/Anammox process from lab-scale sequencing batch reactor (SBR). Nitrogen and phosphorus concentrations were measured every three days. The average nitrogen and phosphorus loads were 0.0503 ± 0.036 g N g(vss)/d and 0.0389 ± 0.013 g P g(vss)/d accordingly. Results have shown that microalgae were able to efficiently remove nitrogen and phosphorus. The average nitrogen removal was 36.46% and phosphorus removal efficiency varied between 93 and 100%.

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

    PubMed

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

    2014-08-01

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

  7. Chlorella starch branching enzyme II (BEII) can complement the function of BEIIb in rice endosperm.

    PubMed

    Sawada, Takayuki; Francisco, Perigio B; Aihara, Satomi; Utsumi, Yoshinori; Yoshida, Mayumi; Oyama, Yasunori; Tsuzuki, Mikio; Satoh, Hikaru; Nakamura, Yasunori

    2009-06-01

    In monocots, starch branching enzyme II (BEII) was functionally differentiated into BEIIa and BEIIb after separation from the dicots, and in cereals BEIIb plays a distinct role in amylopectin biosynthesis in the endosperm. The present study was conducted to examine to what extent a green algal BEII has an overlapping function with BEIIb in starch biosynthesis by introducing the Chlorella BEII gene into an amylose-extender (ae) mutant of rice. Chlorella BEII was found to complement the contribution of the rice endosperm BEIIb to the structures of amylopectin and starch granules because these mutated phenotypes were recovered almost completely to those of the wild type by the expression of Chlorella BEII. When the recombinant BE enzymes were incubated with the rice ae amylopectin, the branching pattern of Chlorella BEII was much more similar to that of rice BEIIb rather than rice BEIIa. Detailed analyses of BE reaction products suggests that BEIIb and Chlorella BEII only transfer chains with a degree of polymerization (DP) of 6 and 7, whereas BEIIa preferably transfers short chains with a DP of about 6-11. These results show that the Chlorella BEII is functionally similar to rice BEIIb rather than BEIIa.

  8. The Tomato Spotted Wilt Virus Genome Is Processed Differentially in its Plant Host Arachis hypogaea and its Thrips Vector Frankliniella fusca

    PubMed Central

    Fletcher, Stephen J.; Shrestha, Anita; Peters, Jonathan R.; Carroll, Bernard J.; Srinivasan, Rajagopalbabu; Pappu, Hanu R.; Mitter, Neena

    2016-01-01

    Thrips-transmitted tospoviruses are economically important viruses affecting a wide range of field and horticultural crops worldwide. Tomato spotted wilt virus (TSWV) is the type member of the Tospovirus genus with a broad host range of more than 900 plant species. Interactions between these viruses and their plant hosts and insect vectors via RNAi pathways are likely a key determinant of pathogenicity. The current investigation, for the first time, compares biogenesis of small RNAs between the plant host and insect vector in the presence or absence of TSWV. Unique viral small interfering RNA (vsiRNA) profiles are evident for Arachis hypogaea (peanut) and Frankliniella fusca (thrips vector) following infection with TSWV. Differences between vsiRNA profiles for these plant and insect species, such as the relative abundance of 21 and 22 nt vsiRNAs and locations of alignment hotspots, reflect the diverse siRNA biosynthesis pathways of their respective kingdoms. The presence of unique vsiRNAs in F. fusca samples indicates that vsiRNA generation takes place within the thrips, and not solely through uptake via feeding on vsiRNAs produced in infected A. hypogaea. The study also shows key vsiRNA profile differences for TSWV among plant families, which are evident in the case of A. hypogaea, a legume, and members of Solanaceae (S. lycopersicum and Nicotiana benthamiana). Distinctively, overall small RNA (sRNA) biogenesis in A. hypogaea is markedly affected with an absence of the 24 nt sRNAs in TSWV-infected plants, possibly leading to wide-spread molecular and phenotypic perturbations specific to this species. These findings add significant information on the host–virus–vector interaction in terms of RNAi pathways and may lead to better crop and vector specific control strategies. PMID:27656190

  9. Comparative toxicity of copper and acridine to fish, Daphnia and algae

    SciTech Connect

    Blaylock, B.G.; Frank, M.L.; McCarthy, J.F.

    1985-01-01

    A comparison was made of the sensitivity of fish, Daphnia and algae to the toxic effects of copper and acridine. A series of toxicity tests was conducted with these organisms, and the following biological endpoints determined: LC50s for fish, LC50s and effects on reproduction of Daphnia and 50% inhibition of the growth rate of algae. The 96-h LCO50s for bluegill (Lepomis macrochirus) and Daphnia magna exposed to copper were 2.2 and 0.13 mg/L, respectively. A chronic exposure to 0.03 mg/L of copper for 14 d significantly decreased reproduction in Daphnia. Exposure to 0.4 and 0.2 mg/L copper inhibited the growth rate of Selenastrum capricornutum and Chlorella vulgaris, respectively, by 50%. The 96-h LC50s for fathead minnows (Pimephales promelas) and D. magna exposed to acridine were 2.3 and 3.1 mg/L, respectively. A chronic exposure to 1.25 mg/L acridine for 14 d significantly inhibited reproduction in Daphnia, and an exposure to 0.9 mg/L inhibited the growth rate of S. capricornutum by 50%. Based on the biological endpoints determined in these tests, Daphnia were more sensitive to copper than were fish or algae. In contrast, the most sensitive biological endpoint in tests with acridine was the inhibition of algal growth. Comparison of these test results indicates that short-term toxicity tests used for screening toxicants for possible environmental effects should include both plant and animal species. 16 references, 4 figures, 4 tables.

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

    PubMed

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

    2014-10-01

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

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

    PubMed

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

    2015-08-01

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

  12. Disappearance of isocitrate lyase enzyme from cells of Chlorella pyrenoidosa

    PubMed Central

    John, P. C. L.; Thurston, C. F.; Syrett, P. J.

    1970-01-01

    1. When acetate-adapted cells of Chlorella are suspended in nitrogen-free medium and supplied with glucose, isocitrate lyase activity disappears from the cells at a rate of about 9%/h. This loss of activity is shown to be accompanied by loss of isocitrate lyase protein. 2. When isocitrate lyase activity is assayed in intact cells after freezing and thawing, the rate of loss of activity after addition of glucose approaches 20%/h. 3. It is shown, by using 35S, that the rate of turnover of isocitrate lyase protein is somewhat lower than that of other major soluble proteins; general protein turnover during nitrogen starvation, and after glucose addition, is too slow to account for the rate of loss of isocitrate lyase protein. 4. Disappearance of isocitrate lyase activity must result from a mechanism that allows degradation of this specific protein under conditions of limiting nitrogen supply. PMID:5492855

  13. Kinetics of phthalate ester biodegradation by Chlorella pyrenoidosa

    SciTech Connect

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

    1995-06-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2014-10-01

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

  16. Biodiesel production in crude oil contaminated environment using Chlorella vulgaris.

    PubMed

    Xaaldi Kalhor, Aadel; Mohammadi Nassab, Adel Dabbagh; Abedi, Ehsan; Bahrami, Ahmad; Movafeghi, Ali

    2016-12-01

    Biodiesel is a valuable alternative to fossil fuels and many countries choose biodiesel as an unconventional energy source. A large number of investigations have been done on microalgae as a source of oil production. In recent years, wastewater pollutions have caused many ecological problems, and therefore, wastewater phycoremediation has attracted the international attention. This paper studied the cultivation of Chlorella vulgaris in a crude oil polluted environment for biodiesel production. Intended concentrations were 10 and 20gperliter (crude oil/water) at two times. The results showed that the growth of C. vulgaris was improved in wastewater and the maximum amount of dry mass and oil was produced at the highest concentration of crude oil (0.41g and 0.15g/l, respectively). In addition, dry mass and oil yield of the microalga were significantly enhanced by increasing the experiment duration.

  17. Thermo-chemical conversion of Chlorella pyrenoidosa to liquid biofuels.

    PubMed

    Duan, Peigao; Jin, Binbin; Xu, Yuping; Yang, Yan; Bai, Xiujun; Wang, Feng; Zhang, Lei; Miao, Jun

    2013-04-01

    The aim of the present study is to find how the solvent polarity affects the liquefaction behavior of Chlorella pyrenoidosa and subsequently using the most suitable solvent identified to explore the solvent/biomass ratio, time, and temperature on the products yield and properties of the bio-oil. The products yield was significantly affected by the solvent type, and ethanol was proven to be the most suitable solvent to convert C. pyrenoidosa into bio-oil from the yield and economic points of view. Temperature is the most influential factor on the products yield and properties of the bio-oil. The HHVs of the bio-oils produced under different reaction conditions are within the range of 27.68-36.45 MJ/kg. The major compounds in bio-oil were esters, fatty acids, alkenes, aldehydes, and amides, and fatty acid ethyl esters were the largest portion.

  18. 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.

  19. Phytoremediation of agriculture runoff by filamentous algae poly-culture for biomethane production, and nutrient recovery for secondary cultivation of lipid generating microalgae.

    PubMed

    Bohutskyi, Pavlo; Chow, Steven; Ketter, Ben; Fung Shek, Coral; Yacar, Dean; Tang, Yuting; Zivojnovich, Mark; Betenbaugh, Michael J; Bouwer, Edward J

    2016-12-01

    An integrated system was implemented for water phytoremediation and biofuel production through sequential cultivation of filamentous algae followed by cultivation of lipid-producing microalgae Chlorella sorokiniana. Natural poly-culture of filamentous algae was grown in agricultural stormwater using the Algal Turf Scrubber®, harvested and subjected for lipid extraction and/or methane production using anaerobic digestion (AD). While filamentous algae lipid content was too low for feasible biodiesel production (<2%), both whole biomass and lipid-extracted algal residues (LEA) yielded ∼0.2LmethanepergVS at loading rates up to 5gVS/L-day. Importantly, essential macro-nutrients and trace elements captured from stormwater were released into the AD effluent as soluble nutrients and were successfully tested as fertilizer replacement for cultivation of lipid-accumulating C. sorokiniana in a subsequent stage. Accordingly, filamentous algae poly-culture was exploited for waste nutrient capturing and biofuel feedstock generation. These nutrients were recovered and reused as a concentrated supplement for potentially high-value microalgae.

  20. Comparison of plastid 16S rRNA (rrn16) genes from Helicosporidium spp.: evidence supporting the reclassification of Helicosporidia as green algae (Chlorophyta).

    PubMed

    Tartar, Aurélien; Boucias, Drion G; Becnel, James J; Adams, Byron J

    2003-11-01

    The Helicosporidia are invertebrate pathogens that have recently been identified as non-photosynthetic green algae (Chlorophyta). In order to confirm the algal nature of the genus Helicosporidium, the presence of a retained chloroplast genome in Helicosporidia cells was investigated. Fragments homologous to plastid 16S rRNA (rrn16) genes were amplified successfully from cellular DNA extracted from two different Helicosporidium isolates. The fragment sequences are 1269 and 1266 bp long, are very AT-rich (60.7 %) and are similar to homologous genes sequenced from non-photosynthetic green algae. Maximum-parsimony, maximum-likelihood and neighbour-joining methods were used to infer phylogenetic trees from an rrn16 sequence alignment. All trees depicted the Helicosporidia as sister taxa to the non-photosynthetic, pathogenic alga Prototheca zopfii. Moreover, the trees identified Helicosporidium spp. as members of a clade that included the heterotrophic species Prototheca spp. and the mesotrophic species Chlorella protothecoides. The clade is always strongly supported by bootstrap values, suggesting that all these organisms share a most recent common ancestor. Phylogenetic analyses inferred from plastid 16S rRNA genes confirmed that the Helicosporidia are non-photosynthetic green algae, close relatives of the genus Prototheca (Chlorophyta, Trebouxiophyceae). Such phylogenetic affinities suggest that Helicosporidium spp. are likely to possess Prototheca-like organelles and organelle genomes.

  1. Photobioreactors for mass cultivation of algae.

    PubMed

    Ugwu, C U; Aoyagi, H; Uchiyama, H

    2008-07-01

    Algae have attracted much interest for production of foods, bioactive compounds and also for their usefulness in cleaning the environment. In order to grow and tap the potentials of algae, efficient photobioreactors are required. Although a good number of photobioreactors have been proposed, only a few of them can be practically used for mass production of algae. One of the major factors that limits their practical application in algal mass cultures is mass transfer. Thus, a thorough understanding of mass transfer rates in photobioreactors is necessary for efficient operation of mass algal cultures. In this review article, various photobioreactors that are very promising for mass production of algae are discussed.

  2. Use of a chemical equilibrium model to describe surface properties and uptake of cadmium, strontium, and lead by Chlorella (UTEX 252)

    SciTech Connect

    Hassett, J.M.

    1988-01-01

    Metal-aquatic biota interactions are important in both natural and engineered systems. In this study, the uptake of cadmium, strontium and lead by the unicellular green alga Chlorella (UTEX 252) was investigated. Variables included metal concentration, pH, and ionic strength. Data gathered included dry weights (mg/l), cell counts (cells/ml), electrophoretic mobilities (EPMs, {mu}m/sec/V/cm) of metal-free and metal-exposed cells, and metal uptake - difference in concentration in filtrate of cell-metal and cell-free metal solutions. Derived data included cell volumes and surface area, uptake on a {mu}M/m{sup 2} basis, {zeta}-potentials, diffuse layer potentials and charge densities. Typical uptake values were 1.1, 5.2, and 6 {mu}M/m{sup 2} for Cd, Pb, and Sr, respectively, from solutions of pH 6, ionic strength 0.02M, and metal concentration 10{sup {minus}4} M. Cell EPMs were insensitive to metal; under certain conditions, however, (pM > 4, pH > 8), cadmium exposed cells exhibited a reversal in surface charge from negative to positive. The chemical equilibrium model MINEQL1 + STANFORD was used to model algal surface properties and metal uptake. Input data included site pK, density, and {Delta}pK, estimated from EPM-pH data. The model described surface properties of Chlorella (UTEX 252) as judged by a close fit of {zeta}-potentials and model-derived diffuse layer potentials. Metal uptake was modelled by adjusting site density and/or metal-surface site equilibrium constants. Attempts to model surface properties and metal uptake simultaneously were not successful.

  3. Combined effect of concentrations of algal food (Chlorella vulgaris) and salt (sodium chloride) on the population growth of Brachionus calyciflorus and Brachionus patulus (Rotifera).

    PubMed

    Peredo-Alvarez, Víctor M; Sarma, S S; Nandini, S

    2003-06-01

    Salinity is an important variable influencing the density and diversity of rotifers. Studies on salt tolerance of rotifers have so far concentrated on euryhaline species while very little information is available on non-euryhaline taxa. In the present work, we have evaluated the combined effects of Chlorella vulgaris and sodium chloride on the population growth of two freshwater rotifers B. calyciflorus and B. patulus. A 24 hr acute tolerance test using NaCl revealed that B. calyciflorus was more resistant (LC50 = 3.75 +/- 0.04 g l-1) than B. patulus (2.14 +/- 0.09 g l-1). The maximal population density (mean +/- standard error) for B. calyciflorus in the control at 4.5 x 10(6) cells ml-1 (algal level) was 80 +/- 5 ind. ml-1, which was nearly a fifth of the one for B. patulus (397 +/- 7 ind. ml-1) under comparable conditions. Data on population growth revealed that regardless of salt concentration, the density of B. calyciflorus increased with increasing food levels, while for B. patulus, this trend was evident only in the controls. Regardless of salt concentration and algal food level, the day of maximal population density was lower (4 +/- 0.5 days) for B. calyciflorus than for B. patulus (11 +/- 1 day). The highest rates of population increase (r values) for B. calyciflorus and B. patulus were 0.429 +/- 0.012 and 0.367 +/- 0.004, respectively, recorded at 4.5 x 10(6) cells ml-1 of Chlorella in the controls. The protective role of algae in reducing the effect of salt stress was more evident in B. calyciflorus than B. patulus.

  4. ["Depilation" by micro-algae?].

    PubMed

    Ditrich, H

    1996-01-01

    Itching, reddening and depilation of body hairs was reported by swimmers in the Attersee-lake in Austria. Initially, an environmental crime was suspected. However, further investigations showed that a biological cause was probably responsible for these symptoms. The accrustations found on body hairs turned out in the scanning electron microscope to be dried mucus containing numerous diatoms. The prevailing micro-algae were identified as Cyclotella comensis. Thus, although the phenomenon had a natural, harmless cause, it may happen again given the appropriate environmental conditions.

  5. (Viruses of eukaryotic green algae): Performance report

    SciTech Connect

    Not Available

    1987-01-01

    The primary objective of this research was to develop the Chlorella-PBCV-1 virus system so that it can be used as a model system for studying gene expression in a photosynthetic eukaryote. Discoveries include the finding that morphologically similar, plaque forming, dsDNA containing viruses are common in nature and can be isolated readily from fresh water; the finding that all of these Chlorella viruses contain methylated bases which range in concentration from 0.1% to 47.5% mVdC and 0 to 37% mWdA and the discovery that infection with at least some of these viruses induces the appearance of DNA modification/restriction systems. 18 refs.

  6. 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.

  7. 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.

  8. 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)

  9. 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.

  10. 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.…

  11. 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.

  12. 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.

  13. 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.

  14. Advances in genetic engineering of marine algae.

    PubMed

    Qin, Song; Lin, Hanzhi; Jiang, Peng

    2012-01-01

    Algae are a component of bait sources for animal aquaculture, and they produce abundant valuable compounds for the chemical industry and human health. With today's fast growing demand for algae biofuels and the profitable market for cosmetics and pharmaceuticals made from algal natural products, the genetic engineering of marine algae has been attracting increasing attention as a crucial systemic technology to address the challenge of the biomass feedstock supply for sustainable industrial applications and to modify the metabolic pathway for the more efficient production of high-value products. Nevertheless, to date, only a few marine algae species can be genetically manipulated. In this article, an updated account of the research progress in marine algal genomics is presented along with methods for transformation. In addition, vector construction and gene selection strategies are reviewed. Meanwhile, a review on the progress of bioreactor technologies for marine algae culture is also revisited.

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

    SciTech Connect

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

    2016-01-07

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

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

    PubMed

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

    2013-01-01

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

  17. Detoxification of chlorella supplement on heterocyclic amines in Korean young adults.

    PubMed

    Lee, Inyeong; Tran, Minhphuong; Evans-Nguyen, Theresa; Stickle, Dawn; Kim, Soyeon; Han, Jaegab; Park, Jong Y; Yang, Mihi

    2015-01-01

    Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) have been established as carcinogenic chemicals in Western diet. This study was performed to estimate HCA exposure levels in Korean daily life and to assess the ability of Chlorella vulgaris to detoxify carcinogenic HCAs in a randomized, double blind, placebo-controlled crossover study with chlorella supplement (N=6, all females, age: 27.17±7.73yr) for 2 weeks. We analyzed HCAs in hydrolyzed urine specimens using LC/TOF-MS. As results, urinary levels of MeIQx, PhIP, and IQx-8-COOH were 323.36±220.11ng/L, 351.59±254.93ng/L, and 130.85±83.22ng/L, respectively. Effects of chlorella to reduce urinary MeIQx were marginally significant (before, 430±226.86pg/mL vs. after, 174.45±101.65pg/mL: 0.05chlorella supplementation. In conclusion, our study demonstrates that current daily levels of HCA exposure in Korean young adults are not lower than those in the Western world. In addition, the effects of chlorella's to detoxify HCAs likely occur by interfering e with absorption or metabolism.

  18. Ruminant Nutrition Symposium: The utility of lipid extracted algae as a protein source in forage or starch-based ruminant diets.

    PubMed

    Lodge-Ivey, S L; Tracey, L N; Salazar, A

    2014-04-01

    Two experiments were conducted to determine the influence of lipid extracted algae (LEA) on OM digestibility, N flow, and rumen fermentation. Six samples of LEA were evaluated representing 2 genus of microalgae (Nannochloropsis spp. [n = 3] or Chlorella spp. [n = 3]). Four dual-flow continuous flow fermenters (2,700 mL) were used in a Latin square design to evaluate LEA in forage or concentrate diets compared with soybean meal. Temperature (39 °C), pH, solid (5%/h) and liquid (10%/h) dilution rates, and feed schedule were maintained constant for all experiments. Each experimental period consisted of 6-d adaptation and 4-d sampling periods. There were 7 treatments consisting of 6 different samples of LEA and a soybean meal control (SOY). Diets for Exp.1 were formulated to be 13.0% CP (DM basis) using either soybean meal or LEA and met or exceeded the requirements of a nonpregnant and nonlactating beef cow (450 kg). The forage portion consisted of sorghum-sudan hay (6.4% CP and 46.2% TDN, DM basis) and alfalfa (26.1% CP and 82.3% TDN, DM basis). Concentrate diets used in Exp. 2 met or exceeded the nutrient requirements of a (400 kg) growing steer and contained 85% fine ground corn and included 7% (DM basis) soybean meal or LEA. Data were analyzed as mixed model considering the effect of each LEA compared with soybean meal. Orthogonal contrasts were used to determine the overall effect of LEA genus vs. SOY. True OM digestibility were not influenced by LEA addition to forage diets (P ≥ 0.08) but increased with Chlorella LEA addition to concentrate diets (P < 0.01) but not Nannochloropsis LEA. Degradation of N was greater for SOY with forage diets and LEA for concentrate diets (P < 0.0001). Total VFA production was greatest for SOY in forage diets and increased when LEA was added to concentrate diets (P < 0.0001). Microbial efficiency did not differ between SOY and LEA in forage diets (P ≤ 0.08). In concentrate diets Nannochloropsis decreased microbial efficiency

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

    PubMed

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

    2014-05-01

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

  20. Effects of paraquat on photosynthetic pigments, antioxidant enzymes, and gene expression in Chlorella pyrenoidosa under mixotrophic compared with autotrophic conditions.

    PubMed

    Zhang, Weiguo; Liu, Min; Zhang, Peiliang; Yu, Fugen; Lu, Shan; Li, Pengfu; Zhou, Junying

    2014-11-01

    Only limited information is available on herbicide toxicity to algae under mixotrophic conditions. In the present study, we studied the effects of the herbicide paraquat on growth, photosynthetic pigments, antioxidant enzymes, and gene expression in Chlorella pyrenoidosa under mixotrophic compared with autotrophic conditions. The mean measured exposure concentrations of paraquat under mixotrophic and autotrophic conditions were in the range of 0.3-3.4 and 0.6-3.6 μM, respectively. Exposure to paraquat for 72 h under both autotrophic and mixotrophic conditions induced decreased growth and chlorophyll (Chl) content, increased superoxide dismutase and peroxidase activities, and decreased transcript abundances of three photosynthesis-related genes (light-independent protochlorophyllide reductase subunit, photosystem II protein D1, and ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit [rbcL]). Compared with autotrophic conditions, the inhibition percentage of growth rate under mixotrophic conditions was lower at 0.8 μM paraquat, whereas it was greater at 1.8 and 3.4 μM paraquat. With exposure to 0.8-3.4 μM paraquat, the inhibition rates of Chl a and b content under mixotrophic conditions (43.1-52.4% and 54.6-59.7%, respectively) were greater compared with autotrophic conditions, whereas the inhibition rate of rbcL gene transcription under mixotrophic conditions (35.7-44.0%) was lower. These data showed that similar to autotrophic conditions, paraquat affected the activities of antioxidant enzymes and decreased Chl synthesis and transcription of photosynthesis-related genes in C. pyrenoidosa under mixotrophic conditions, but a differential susceptibility to paraquat toxicity occurred between autotrophically versus mixotrophically grown cells.

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

    NASA Astrophysics Data System (ADS)

    Moazeni, Faegheh

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

  2. Chlorella Virus Encoded Deoxyuridine triphosphatases Exhibit different Temperature Optima

    SciTech Connect

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

    2005-01-01

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

  3. 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

  4. 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).

  5. 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.

  6. High-density fermentation of microalga Chlorella protothecoides in bioreactor for microbio-diesel production.

    PubMed

    Xiong, Wei; Li, Xiufeng; Xiang, Jinyi; Wu, Qingyu

    2008-02-01

    Agal-fermentation-based microbio-diesel production was realized through high-cell-density fermentation of Chlorella protothecoides and efficient transesterification process. Cell density achieved was 16.8 g l(-1) in 184 h and 51.2 g l(-1) in 167 h in a 5-l bioreactor by performing preliminary and improved fed-batch culture strategy, respectively. The lipid content was 57.8, 55.2, and 50.3% of cell dry weight from batch, primary, and improved fed-batch culture in 5-l bioreactor. Transesterification was catalyzed by immobilized lipase, and the conversion rate reached up to 98%. The properties of biodiesel from Chlorella were comparable to conventional diesel fuel and comply with US standard for Biodiesel. In a word, the approach including high-density fermentation of Chlorella and enzymatic transesterification process were set up and proved to be a promising alternative for biodiesel production.

  7. Cell-wall disruption and lipid/astaxanthin extraction from microalgae: Chlorella and Haematococcus.

    PubMed

    Kim, Dong-Yeon; Vijayan, Durairaj; Praveenkumar, Ramasamy; Han, Jong-In; Lee, Kyubock; Park, Ji-Yeon; Chang, Won-Seok; Lee, Jin-Suk; Oh, You-Kwan

    2016-01-01

    Recently, biofuels and nutraceuticals produced from microalgae have emerged as major interests, resulting in intensive research of the microalgal biorefinery process. In this paper, recent developments in cell-wall disruption and extraction methods are reviewed, focusing on lipid and astaxanthin production from the biotechnologically important microalgae Chlorella and Haematococcus, respectively. As a common, critical bottleneck for recovery of intracellular components such as lipid and astaxanthin from these microalgae, the composition and structure of rigid, thick cell-walls were analyzed. Various chemical, physical, physico-chemical, and biological methods applied for cell-wall breakage and lipid/astaxanthin extraction from Chlorella and Haematococcus are discussed in detail and compared based on efficiency, energy consumption, type and dosage of solvent, biomass concentration and status (wet/dried), toxicity, scalability, and synergistic combinations. This report could serve as a useful guide to the implementation of practical downstream processes for recovery of valuable products from microalgae including Chlorella and Haematococcus.

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

    PubMed

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

    2016-06-01

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

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

    PubMed Central

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

    2013-01-01

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

  10. Chlorella viruses contain genes encoding a complete polyamine biosynthetic pathway

    PubMed Central

    Baumann, Sascha; Sander, Adrianne; Gurnon, James R.; Yanai-Balser, Giane; VanEtten, James L.; Piotrowski, Markus

    2007-01-01

    Two genes encoding the putative polyamine biosynthetic enzymes agmatine iminohydrolase (AIH) and N-carbamoylputrescine amidohydrolase (CPA) were cloned from the chloroviruses PBCV-1, NY-2A and MT325. They were expressed in Escherichia coli to form C-terminal (His)6-tagged proteins and the recombinant proteins were purified by Ni2+- binding affinity chromatography. The biochemical properties of the two enzymes are similar to AIH and CPA enzymes from Arabidopsis thaliana and Pseudomonas aeruginosa. Together with the previously known virus genes encoding ornithine/arginine decarboxlyase (ODC/ADC) and homospermidine synthase, the chloroviruses have genes that encode a complete set of functional enzymes that synthesize the rare polyamine homospermidine from arginine via agmatine, N-carbamoylputrescine and putrescine. The PBCV-1 aih and cpa genes are expressed early during virus infection together with the odc/adc gene, suggesting that biosynthesis of putrescine is important in early stages of viral replication. The aih and cpa genes are widespread in the chlorella viruses. PMID:17101165

  11. Assessment of photosynthesis regulation in mixotrophically cultured microalga Chlorella sorokiniana

    DOE PAGES

    Li, Tingting; Kirchhoff, Helmut; Gargouri, Mahmoud; ...

    2016-07-19

    Mixotrophic growth of microalgae offers great potential as an efficient strategy for biofuel production. In this study, photosynthetic regulation of mixotrophically cultured Chlorella sorokiniana cells was systematically evaluated. Mixotrophic cells in the exponential growth phase showed the highest photosynthetic activity, where maximum photosynthetic O2 evolution was approximately 3- and 4-fold higher than cells in the same phase grown photoautotrophically in 1% CO2 (in air) and air, respectively. Additionally, characteristic chlorophyll fluorescence parameters demonstrated that no limitation in electron transport downstream of PSII was detected in mixotrophic cells. Up-regulation of photosynthetic activity was associated with high total ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco)more » carboxylase activity and expression level of phosphoribulokinase (PRK). After 3 days, photosynthetic O2 evolution of mixotrophic cells that went to the stationary phase, was strongly reduced, with reduced photochemical efficiency and reorganization of the PSII complex. Simultaneously, enzymatic activity for Rubisco carboxylase and mRNA levels of Rubisco and PRK diminished. Importantly, there was almost no non-photochemical quenching for mixotrophic cells, whether grown in log or stationary phase. A decline in the quantum efficiency of PSII and an oxidized plastoquinone pool (PQ pool) was observed under N-depleted conditions during mixotrophic growth. Finally, these results demonstrate that photosynthesis is regulated differently in mixotrophically cultured C. sorokiniana cells than in cells grown under photoautotrophic conditions, with a particularly strong impact by nitrogen levels in the cells.« less

  12. Lutein recovery from Chlorella sp. ESP-6 with coagulants.

    PubMed

    Utomo, Rhesa Pramudita; Chang, Yin-Ru; Lee, Duu-Jong; Chang, Jo-Shu

    2013-07-01

    Production of algal lutein included cell cultivation, biomass harvesting, cell wall disruption, and subsequent purification if needed. This work cultivated Chlorella sp. ESP-6 cells in photobioreactor to a biomass content of 1.1 gl(-1) and then the freezing-grinding, ultrasonic treatment (20 and 42kHz) and microwave treatment were used to disrupt the cell walls for recover intracellular lutein. The grinding recovered more lutein than ultrasound or microwave pretreatment. Single coagulation using >30 mgl(-1) chitosan or dual-conditioning using 10 mg l(-1) polyaluminum chloride and 10 mgl(-1) chitosan effectively enhance sedimentation and membrane filtration efficiency of algal suspensions. However, the presence of coagulants lowers the lutein yield from algal biomass in the subsequent 20 kHz ultrasound treatment and purification process. Simulation results revealed affine adsorption of lutein onto chitosan molecules via hydroxyl-amine interaction. The possible drawback by pre-treatment stage should be considered together with the subsequent recovery stage in whole process assessment.

  13. A functional calcium-transporting ATPase encoded by chlorella viruses

    PubMed Central

    Bonza, Maria Cristina; Martin, Holger; Kang, Ming; Lewis, Gentry; Greiner, Timo; Giacometti, Sonia; Van Etten, James L.; De Michelis, Maria Ida; Thiel, Gerhard; Moroni, Anna

    2010-01-01

    Calcium-transporting ATPases (Ca2+ pumps) are major players in maintaining calcium homeostasis in the cell and have been detected in all cellular organisms. Here, we report the identification of two putative Ca2+ pumps, M535L and C785L, encoded by chlorella viruses MT325 and AR158, respectively, and the functional characterization of M535L. Phylogenetic and sequence analyses place the viral proteins in group IIB of P-type ATPases even though they lack a typical feature of this class, a calmodulin-binding domain. A Ca2+ pump gene is present in 45 of 47 viruses tested and is transcribed during virus infection. Complementation analysis of the triple yeast mutant K616 confirmed that M535L transports calcium ions and, unusually for group IIB pumps, also manganese ions. In vitro assays show basal ATPase activity. This activity is inhibited by vanadate, but, unlike that of other Ca2+ pumps, is not significantly stimulated by either calcium or manganese. The enzyme forms a 32P-phosphorylated intermediate, which is inhibited by vanadate and not stimulated by the transported substrate Ca2+, thus confirming the peculiar properties of this viral pump. To our knowledge this is the first report of a functional P-type Ca2+-transporting ATPase encoded by a virus. PMID:20573858

  14. A functional calcium-transporting ATPase encoded by chlorella viruses.

    PubMed

    Bonza, Maria Cristina; Martin, Holger; Kang, Ming; Lewis, Gentry; Greiner, Timo; Giacometti, Sonia; Van Etten, James L; De Michelis, Maria Ida; Thiel, Gerhard; Moroni, Anna

    2010-10-01

    Calcium-transporting ATPases (Ca(2+) pumps) are major players in maintaining calcium homeostasis in the cell and have been detected in all cellular organisms. Here, we report the identification of two putative Ca(2+) pumps, M535L and C785L, encoded by chlorella viruses MT325 and AR158, respectively, and the functional characterization of M535L. Phylogenetic and sequence analyses place the viral proteins in group IIB of P-type ATPases even though they lack a typical feature of this class, a calmodulin-binding domain. A Ca(2+) pump gene is present in 45 of 47 viruses tested and is transcribed during virus infection. Complementation analysis of the triple yeast mutant K616 confirmed that M535L transports calcium ions and, unusually for group IIB pumps, also manganese ions. In vitro assays show basal ATPase activity. This activity is inhibited by vanadate, but, unlike that of other Ca(2+) pumps, is not significantly stimulated by either calcium or manganese. The enzyme forms a (32)P-phosphorylated intermediate, which is inhibited by vanadate and not stimulated by the transported substrate Ca(2+), thus confirming the peculiar properties of this viral pump. To our knowledge this is the first report of a functional P-type Ca(2+)-transporting ATPase encoded by a virus.

  15. Use of diluted urine for cultivation of Chlorella vulgaris.

    PubMed

    Jaatinen, Sanna; Lakaniemi, Aino-Maija; Rintala, Jukka

    2016-01-01

    Our aim was to study the biomass growth of microalga Chlorella vulgaris using diluted human urine as a sole nutrient source. Batch cultivations (21 days) were conducted in five different urine dilutions (1:25-1:300), in 1:100-diluted urine as such and with added trace elements, and as a reference, in artificial growth medium. The highest biomass density was obtained in 1:100-diluted urine with and without additional trace elements (0.73 and 0.60 g L(-1), respectively). Similar biomass growth trends and densities were obtained with 1:25- and 1:300-diluted urine (0.52 vs. 0.48 gVSS L(-1)) indicating that urine at dilution 1:25 can be used to cultivate microalgal based biomass. Interestingly, even 1:300-diluted urine contained sufficiently nutrients and trace elements to support biomass growth. Biomass production was similar despite pH-variation from < 5 to 9 in different incubations indicating robustness of the biomass growth. Ammonium formation did not inhibit overall biomass growth. At the beginning of cultivation, the majority of the biomass consisted of living algal cells, while towards the end, their share decreased and the estimated share of bacteria and cell debris increased.

  16. Toxicological Responses of Chlorella vulgaris to Dichloromethane and Dichloroethane

    PubMed Central

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

    2014-01-01

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

  17. 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.

  18. 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

  19. 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...

  20. 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...

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

    PubMed

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

    2014-11-01

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

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

    PubMed

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

    2016-01-01

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

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

    PubMed

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

    2014-01-01

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

  4. Pharmaceuticals and Surfactants from Alga-Derived Feedstock: Amidation of Fatty Acids and Their Derivatives with Amino Alcohols.

    PubMed

    Tkacheva, Anastasia; Dosmagambetova, Inkar; Chapellier, Yann; Mäki-Arvela, Päivi; Hachemi, Imane; Savela, Risto; Leino, Reko; Viegas, Carolina; Kumar, Narendra; Eränen, Kari; Hemming, Jarl; Smeds, Annika; Murzin, Dmitry Yu

    2015-08-24

    Amidation of renewable feedstocks, such as fatty acids, esters, and Chlorella alga based biodiesel, was demonstrated with zeolites and mesoporous materials as catalysts and ethanolamine, alaninol, and leucinol. The last two can be derived from amino acids present in alga. The main products were fatty alkanol amides and the corresponding ester amines, as confirmed by NMR and IR spectroscopy. Thermal amidation of technical-grade oleic acid and stearic acid at 180 °C with ethanolamine were non-negligible; both gave 61% conversion. In the amidation of stearic acid with ethanolamine, the conversion over H-Beta-150 was 80% after 3 h, whereas only 63% conversion was achieved for oleic acid; this shows that a microporous catalyst is not suitable for this acid and exhibits a wrinkled conformation. The highest selectivity to stearoyl ethanolamide of 92% was achieved with mildly acidic H-MCM-41 at 70% conversion in 3 h at 180 °C. Highly acidic catalysts favored the formation of the ester amine, whereas the amide was obtained with a catalyst that exhibited an optimum acidity. The conversion levels achieved with different fatty acids in the range C12-C18 were similar; this shows that the fatty acid length does not affect the amidation rate. The amidation of methyl palmitate and biodiesel gave low conversions over an acidic catalyst, which suggested that the reaction mechanism in the amidation of esters was different.

  5. Phenology and duration of remigial moult in Surf Scoters (Melanitta perspicillata) and White-winged Scoters (Melanitta fusca) on the Pacific coast of North America

    USGS Publications Warehouse

    Dickson, Rian D.; Esler, Daniel; Hupp, Jerry W.; Anderson, E.M.; Evenson, J.R.; Barrett, J.

    2012-01-01

    By quantifying phenology and duration of remigial moult in Surf Scoters (Melanitta perspicillata (L., 1758)) and White-winged Scoters (Melanitta fusca (L., 1758)), we tested whether timing of moult is dictated by temporal optima or constraints. Scoters (n = 3481) were captured during moult in Alaska, British Columbia, and Washington, and remigial emergence dates were determined. We provide evidence for a pre-emergence interval of 7.3 days that occurs after old primaries are shed and before new ones become visible. All age and sex classes of both scoter species exhibited a wide range of emergence dates (Surf Scoters: 26 June to 22 September; White-winged Scoters: 6 July to 21 September) suggestive of a lack of strong temporal optima for remigial moult. For both species, timing of moult was influenced by site, year, age, and sex. Relative to other waterfowl species, scoters have typical remigial growth rates (Surf Scoters: 3.9 mm·day–1; White-winged Scoters: 4.3 mm·day–1) but a long flightless period (34–49 days), in part because their relatively high wing-loading requires a greater proportion of feather regrowth to regain flight. Our data suggest that moulting scoters are not under strong selective pressure to complete moult quickly.

  6. Assessment of the vacuolar Na+/H+ antiporter (NHX1) transcriptional changes in Leptochloa fusca L. in response to salt and cadmium stresses

    PubMed Central

    Adabnejad, Hamed; Kavousi, Hamid Reza; Hamidi, Hadi; Tavassolian, Iraj

    2015-01-01

    Sodium/proton exchangers (NHX) are key players in plant responses to salinity and have a central role in establishing ion homeostasis. NHXs can be localized in tonoplast or plasma membranes, where they exchange sodium ions for protons, resulting in the removal of ions from the cytosol into vacuole or extracellular spaces. In the present study, the expression pattern of the gene encoding Na+/H+ antiporter in the vacuolarmembrane (NHX1 gene) in Leptochloa fusca (Kallar grass) was measured by a semi- quantitative RT-PCR method under different treatments of NaCl and CdCl2. Results indicated that NaCl positively affected expression levels of LfNHX1, and that the amount of LfNHX1 mRNA increased in conjunction with the rise of salinity pressure, This finding suggests that vacuolar Na+/H+ antiporter might play an important role in the salt tolerance ability of kallar grass. The results also showed that cadmium exposure significantly modulated the mRNA expression of the LfNHX1 gene, suggesting that cadmium exposure disturbed Na+ homeostasis across the tonoplast and decreased the salt tolerance ability of kallar grass. PMID:27844005

  7. Comparison of Thermobifida fusca Cellulases Expressed in Escherichia coli and Nicotiana tabacum Indicates Advantages of the Plant System for the Expression of Bacterial Cellulases.

    PubMed

    Klinger, Johannes; Fischer, Rainer; Commandeur, Ulrich

    2015-01-01

    The economic conversion of lignocellulosic biomass to biofuels requires in addition to pretreatment techniques access to large quantities of inexpensive cellulases to be competitive with established first generation processes. A solution to this problem could be achieved by plant based expression of these enzymes. We expressed the complete set of six cellulases and an additional β-glucosidase expressed from Thermobifida fusca in the bacterium Escherichia coli and in tobacco plants (Nicotiana tabacum). This was done to determine whether functional enzyme expression was feasible in these organisms. In extracts of recombinant E. coli cells, five of the proteins were detected by western blot analysis, but exocellulases E3 and E6 were undetectable. In the plant-based expression system we were able to detect all six cellulases but not the β-glucosidase even though activity was detectable. When E. coli was used as the expression system, endocellulase E2 was active, while endocellulases E1 and E5 showed only residual activity. The remaining cellulases appeared completely inactive against the model substrates azo-carboxymethyl-cellulose (Azo-CMC) and 4-methylumbelliferyl-cellobioside (4-MUC). Only the β-glucosidase showed high activity against 4-MUC. In contrast, all the plant-derived enzymes were active against the respective model substrates. Our data indicate that some enzymes of bacterial origin are more active and more efficiently expressed in plants than in a bacterial host.

  8. Inhibition of FUSCA3 degradation at high temperature is dependent on ABA signaling and is regulated by the ABA/GA ratio.

    PubMed

    Chiu, Rex Shun; Saleh, Yazan; Gazzarrini, Sonia

    2016-11-01

    During seed imbibition at supra-optimal temperature, an increase in the abscisic acid (ABA)/gibberellin (GA) ratio imposes secondary dormancy to prevent germination (thermoinhibition). FUSCA3 (FUS3), a positive regulator of seed dormancy, accumulates in seeds imbibed at high temperature and increases ABA levels to inhibit germination. Recently, we showed that ABA inhibits FUS3 degradation at high temperature, and that ABA and high temperature also inhibit the ubiquitin-proteasome system, by dampening both proteasome activity and protein polyubiquitination. Here, we investigated the role of ABA signaling components and the ABA antagonizing hormone, GA, in the regulation of FUS3 levels. We show that the ABA receptor mutant, pyl1-1, is less sensitive to ABA and thermoinhibition. In this mutant background, FUS3 degradation in vitro is faster. Similarly, GA alleviates thermoinhibition and also increases FUS3 degradation. These results indicate that inhibition of FUS3 degradation at high temperature is dependent on a high ABA/GA ratio and a functional ABA signaling pathway. Thus, FUS3 constitutes an important node in ABA-GA crosstalk during germination at supra-optimal temperature.

  9. Comparison of Thermobifida fusca Cellulases Expressed in Escherichia coli and Nicotiana tabacum Indicates Advantages of the Plant System for the Expression of Bacterial Cellulases

    PubMed Central

    Klinger, Johannes; Fischer, Rainer; Commandeur, Ulrich

    2015-01-01

    The economic conversion of lignocellulosic biomass to biofuels requires in addition to pretreatment techniques access to large quantities of inexpensive cellulases to be competitive with established first generation processes. A solution to this problem could be achieved by plant based expression of these enzymes. We expressed the complete set of six cellulases and an additional β-glucosidase expressed from Thermobifida fusca in the bacterium Escherichia coli and in tobacco plants (Nicotiana tabacum). This was done to determine whether functional enzyme expression was feasible in these organisms. In extracts of recombinant E. coli cells, five of the proteins were detected by western blot analysis, but exocellulases E3 and E6 were undetectable. In the plant-based expression system we were able to detect all six cellulases but not the β-glucosidase even though activity was detectable. When E. coli was used as the expression system, endocellulase E2 was active, while endocellulases E1 and E5 showed only residual activity. The remaining cellulases appeared completely inactive against the model substrates azo-carboxymethyl-cellulose (Azo-CMC) and 4-methylumbelliferyl-cellobioside (4-MUC). Only the β-glucosidase showed high activity against 4-MUC. In contrast, all the plant-derived enzymes were active against the respective model substrates. Our data indicate that some enzymes of bacterial origin are more active and more efficiently expressed in plants than in a bacterial host. PMID:26648951

  10. Ca2+ and Mg2+ binding site engineering increases the degradation of polyethylene terephthalate films by polyester hydrolases from Thermobifida fusca.

    PubMed

    Then, Johannes; Wei, Ren; Oeser, Thorsten; Barth, Markus; Belisário-Ferrari, Matheus R; Schmidt, Juliane; Zimmermann, Wolfgang

    2015-04-01

    Several bacterial polyester hydrolases are able to hydrolyze the synthetic polyester polyethylene terephthalate (PET). For an efficient enzymatic degradation of PET, reaction temperatures close to the glass transition temperature of the polymer need to be applied. The esterases TfH, BTA2, Tfu_0882, TfCut1, and TfCut2 produced by the thermophilic actinomycete Thermobifida fusca exhibit PET-hydrolyzing activity. However, these enzymes are not sufficiently stable in this temperature range for an efficient degradation of post-consumer PET materials. The addition of Ca2+ or Mg2+ cations to the enzymes resulted in an increase of their melting points between 10.8 and 14.1°C determined by circular dichroism spectroscopy. The thermostability of the polyester hydrolases was sufficient to degrade semi-crystalline PET films at 65°C in the presence of 10 mM Ca2+ and 10 mM Mg2+ resulting in weight losses of up to 12.9% after a reaction time of 48 h. The residues Asp174, Asp204, and Glu253 were identified by molecular dynamics simulations as potential binding residues for the two cations in TfCut2. This was confirmed by their substitution with arginine, resulting in a higher thermal stability of the corresponding enzyme variants. The generated variants of TfCut2 represent stabilized catalysts suitable for PET hydrolysis reactions performed in the absence of Ca2+ or Mg2+.

  11. Complementation of Seed Maturation Phenotypes by Ectopic Expression of ABSCISIC ACID INSENSITIVE3, FUSCA3 and LEAFY COTYLEDON2 in Arabidopsis.

    PubMed

    Roscoe, Thomas T; Guilleminot, Jocelyne; Bessoule, Jean-Jacques; Berger, Frédéric; Devic, Martine

    2015-06-01

    ABSCISIC ACID INSENSITIVE3 (ABI3), FUSCA3 (FUS3) and LEAFY COTYLEDON2 (LEC2), collectively the AFL, are master regulators of seed maturation processes. This study examined the role of AFL in the production of seed reserves in Arabidopsis. Quantification of seed reserves and cytological observations of afl mutant embryos show that protein and lipid but not starch reserves are spatially regulated by AFL. Although AFL contribute to a common regulation of reserves, ABI3 exerts a quantitatively greater control over storage protein content whereas FUS3 controls lipid content to a greater extent. Although ABI3 controls the reserve content throughout the embryo, LEC2 and FUS3 regulate reserves in distinct embryonic territories. By analyzing the ability of an individual ectopically expressed AFL to suppress afl phenotypes genetically, we show that conserved domains common to each component of the AFL are sufficient for the initiation of storage product synthesis and the establishment of embryo morphology. This confirms redundancy among the AFL and indicates a threshold necessary for function within the AFL pool. Since no individual AFL was able to suppress the tolerance to desiccation, mid- and late-maturation programs were uncoupled.

  12. Heterologous expression of Thermobifida fusca thermostable alpha-amylase in Yarrowia lipolytica and its application in boiling stable resistant sago starch preparation.

    PubMed

    Yang, Chao-Hsun; Huang, Yu-Chun; Chen, Cheng-Yu; Wen, Chia-Ying

    2010-09-01

    A gene encoding the thermostable alpha-amylase in Thermobifida fusca NTU22 was amplified by PCR, sequenced, and cloned into Yarrowia lipolytica P01g host strain using the vector pYLSC1 allowing constitutive expression and secretion of the protein. Recombinant expression resulted in high levels of extracellular amylase production, as high as 730 U/l in the Hinton flask culture broth. It is higher than that observed in P. pastoris expression system and E. coli expression system. The purified amylase showed a single band at about 65 kDa by SDS-polyacrylamide gel electrophoresis and this agrees with the predicted size based on the nucleotide sequence. About 70% of the original activity remained after heat treatment at 60 degrees C for 3 h. The optimal pH and temperature of the purified amylase were 7.0 and 60 degrees C, respectively. The purified amylase exhibited a high level of activity with raw sago starch. After 72-h treatment, the DP(w) of raw sago starch obviously decreased from 830,945 to 237,092. The boiling stable resistant starch content of the sago starch increased from 8.3 to 18.1%. The starch recovery rate was 71%.

  13. Expression of Thermobifida fusca thermostable raw starch digesting alpha-amylase in Pichia pastoris and its application in raw sago starch hydrolysis.

    PubMed

    Yang, Chao-Hsun; Huang, Yu-Chun; Chen, Cheng-Yu; Wen, Chia-Ying

    2010-04-01

    A gene encoding the thermostable raw starch digesting alpha-amylase in Thermobifida fusca NTU22 was amplified by PCR, sequenced and cloned into Pichia pastoris X-33 host strain using the vector pGAPZalphaA, allowing constitutive expression and secretion of the protein. Recombinant expression resulted in high levels of extracellular amylase production, as high as 510 U/l in the Hinton flask culture broth. The purified amylase showed a single band at about 65 kDa by SDS-polyacrylamide gel electrophoresis after being treated with endo-beta-N-acetylglycosaminidase H, and this agrees with the predicted size based on the nucleotide sequence. About 75% of the original activity remained after heat treatment at 60 degrees C for 3 h. The optimal pH and temperature of the purified amylase were 7.0 and 60 degrees C, respectively. The purified amylase exhibited a high level of activity with raw sago starch. After 48-h treatment, the DPw of raw sago starch obviously decreased from 830,945 to 378,732. The surface of starch granules was rough, and some granules displayed deep cavities.

  14. Endogenous 4-hydroxy-2-nonenal in microalga Chlorella kessleri acts as a bioactive indicator of pollution with common herbicides and growth regulating factor of hormesis.

    PubMed

    Spoljaric, Dubravka; Cipak, Ana; Horvatic, Janja; Andrisic, Luka; Waeg, Georg; Zarkovic, Neven; Jaganjac, Morana

    2011-10-01

    Oxidative stress, i.e. excessive production of reactive oxygen species (ROS), leads to lipid peroxidation and to formation of reactive aldehydes (e.g. 4-hydroxy-2-nonenal; HNE), which act as second messengers of free radicals. It was previously shown that herbicides can induce ROS production in algal cells. In the current paper, the unicellular green microalga Chlorella kessleri was used to study the effect of two herbicides (S-metolachlor and terbuthylazine) and hydrogen peroxide (H(2)O(2)) on oxidative stress induction, HNE formation, chlorophyll content and the cell growth. Production of HNE was detected in this study for the first time in the cells of unicellular green algae using the antibody specific for the HNE-histidine adducts revealing the HNE-histidine adducts even in untreated, control C. kessleri. Exposure of algal cells to herbicides and H(2)O(2) increased the ROS production, modifying production of HNE. Namely, 4h upon treatment the levels of HNE-histidine conjugates were below controls. However, their amount increased afterwards. The increase of HNE levels in algae was followed by their increased growth rate, as was previously described for human carcinoma cells. Hence, changes in the cellular HNE content upon herbicide treatment inducing lipid oxidative stress and alterations in cellular growth rate of C. kessleri resemble adaptation of malignant cells to the HNE treatment. Therefore, as an addition to the standard toxicity tests, the evaluation of HNE-protein adducts in C. kessleri might indicate environmental pollution with lipid peroxidation-inducing herbicides. Finally, C. kessleri might be a convenient experimental model to further study cellular hormetic adaptation to oxidative stress-derived aldehydes.

  15. Fast algal eco-toxicity assessment: Influence of light intensity and exposure time on Chlorella vulgaris inhibition by atrazine and DCMU.

    PubMed

    Camuel, Alexandre; Guieysse, Benoit; Alcántara, Cynthia; Béchet, Quentin

    2017-06-01

    In order to develop a rapid assay suitable for algal eco-toxicity assessments under conditions representative of natural ecosystems, this study evaluated the short-term (<1h) response of algae exposed to atrazine and DCMU using oxygen productivity measurements. When Chlorella vulgaris was exposed to these herbicides under 'standard' low light intensity (as prescribed by OECD201 guideline), the 20min-EC50 values recorded via oxygen productivity (atrazine: 1.32±0.07μM; DCMU: 0.31±0.005μM) were similar the 96-h EC50 recorded via algal growth (atrazine: 0.56μM; DCMU: 0.41μM), and within the range of values reported in the literature. 20min-EC50 values increased by factors of 3.0 and 2.1 for atrazine and DCMU, respectively, when light intensity increased from 60 to 1400μmolm(-2)s(-1) of photosynthetically active radiation, or PAR. Further investigation showed that exposure time significantly also impacted the sensitivity of C. vulgaris under high light intensity (>840μmolm(-2)s(-1) as PAR) as the EC50 for atrazine and DCMU decreased by up to 6.2 and 2.1 folds, respectively, after 50min of exposure at a light irradiance of 1400μmolm(-2)s(-1) as PAR. This decrease was particularly marked at high light intensities and low algae concentrations and is explained by the herbicide disruption of the electron transfer chain triggering photo-inhibition at high light intensities. Eco-toxicity assessments aiming to understand the potential impact of toxic compounds on natural ecosystems should therefore be performed over sufficient exposure times (>20min for C. vulgaris) and under light intensities relevant to these ecosystems.

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  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.