Oscillatoria Sp Research Articles

Lingaoamide, a cyclic heptapeptide from a Chinese freshwater cyanobacterium Oscillatoria sp.

Lingaoamide (1), a new cyclic heptapeptide natural product, was isolated from a freshwater Oscillatoria cyanobacterium. The producing organism was collected in Chinese water spinach paddy farm fields in Lingao County, Hainan, China. The structure of 1 was determined by conventional mass spectrometry, NMR spectroscopy, and chemical degradation studies. Lingaoamide concentration-dependently up-regulates the biogenesis of pro-pathogenic melanin pigments (melanogenesis) in the rice blast fungus, Magnaporthe grisea, when tested in vitro. This molecule also exhibits weak in vitro inhibition (MIC 32 μg/mL) of Gram-negative Pseudomonas aeruginosa and Gram-positive Bacillus pumilus, and does not appear to impact plant growth or immune response in vivo using the model organism, Arabidopsis thaliana.

Biosorption of Copper (II) Ion from Aqueous Solution Using Algae Biomass Oscillatoria sp

Biosorption is the method of removing heavy metal from the aqueous solution. Oscillatoria sp microalgae were used to adsorb copper ions in this study. The maximum biosorption capacity was obtained 4.9 mg/g at pH of 9 with an efficiency of 99%. The algae dosage in 0.1 g gave the maximum capacity of 12.33 mg/g. The maximum contact time occurred at 60 minutes with an adsorption capacity of 19.87 mg/g. Adsorption Cu2+ by microalgae Oscillatoria sp followed by the Langmuir and Freundlich isotherms. According to the Langmuir models the value of qm is 217.39 mg/g , KL = 8.8 x10-4 L/mg, and R2 = 0.9999. The Freundlich model showed the coefficient correlation R2 = 1, 1/n = 1.0162, and Kf = 5.39. The model of pseudo-second-order with qe = 4.98 mg/g, k2 = 81.38 g mg-1 h-1, and R2 = 1.

Impact of wastewater cultivation on pollutant removal, biomass production, metabolite biosynthesis, and carbon dioxide fixation of newly isolated cyanobacteria in a multiproduct biorefinery paradigm

The impact of wastewater cultivation was studied on pollutant removal, biomass production, and biosynthesis of high-value metabolites by newly isolated cyanobacteria namely Acaryochloris marina BERC03, Oscillatoria sp. BERC04, and Pleurocapsa sp. BERC06. During cultivation in urabn wastewater, its pH used to adjust from pH 8.0 to 11, offering contamination-free cultivation, and flotation-based easy harvesting. Besides, wastewater cultivation improved biomass production by 1.3-fold when compared to control along with 3.54–4.2 gL-1 of CO2 fixation, concomitantly removing suspended organic matter, total nitrogen, and phosphorus by 100%, 53%, and 88%, respectively. Biomass accumulated 26–36% carbohydrates, 15–28% proteins, 38–43% lipids, and 6.3–9.5% phycobilins, where phycobilin yield was improved by 1.6-fold when compared to control. Lipids extracted from the pigment-free biomass were trans-esterified to biodiesel where pigment extraction showed no negative impact on quality of the biodiesel. These strains demonstrated the potential to become feedstock of an integrated biorefinery using urban wastewater as low-cost growth media.

Enhancement of Phycobiliprotein Accumulation in Thermotolerant Oscillatoria sp. through Media Optimization.

Phycobiliproteins (PBPs) are a group of brilliant pigment proteins found in cyanobacteria and red algae; their synthesis and accumulation depend on several factors such as the type of strain employed, nutrient concentration, light intensity, light regimes, and others. This study evaluates the effect of macronutrients (citrate buffer, NaNO3, K2HPO4, MgSO4, CaCl2, Na2CO3, and EDTA) and the concentration of trace metals in BG-11 media on the accumulation of PBPs in a thermotolerant strain of Oscillatoria sp. The strain was grown in BG-11 media at 28 °C with a light:dark cycle of 12:12 h at 100 μmol m–2 s–1 for 15 days, and the effect of nutrients was evaluated using a Plackett–Burman Design followed by optimization using a response surface methodology. Results from the concentration of trace metals show that it can be reduced up to half-strength in its initial concentration without affecting both biomass and PBPs. Results from the Plackett–Burman Design revealed that only NaNO3, Na2CO3, and K2HPO4 show a significant increase in PBP production. Optimization employed a central Non-Factorial Response Surface Design with three levels and four factors (34) using NaNO3, Na2CO3, K2HPO4, and trace metals as variables, while the other components of BG-11 media (citrate buffer, MgSO4, CaCl2, and EDTA) were used in half of their initial concentration. Results from the optimization show that interaction between Na2CO3 and K2HPO4 highly increased PBPs’ concentration, with values of 15.21, 3.95, and 1.89 (% w/w), respectively. These results demonstrate that identifying and adjusting the concentration of critical nutrients can increase the concentration of PBPs up to two times for phycocyanin and allophycocyanin while four times for phycoerythrin. Finally, the reduction in non-key nutrients’ concentration will reduce the production costs of colorants at an industrial scale and increase the sustainability of the process.

Isolation and in silico analysis of antioxidants in response to temporal variations in the cyanobacterium Oscillatoria sp.

The present study aims to investigate the responses of certain antioxidants and photosynthetic pigments to temporal variations during winter, summer and rainy seasons in the cyanobacterium Oscillatoria sp. inhabiting sewage water. Native-PAGE enzyme profile of superoxide dismutase (SOD) explicated that while isoform number 1 identified as Mn-SOD was observed solely during rainy season, isoform number 2 identified as Fe-SOD was present persistently in all the three seasons. However, densitometry analyses illustrated intra-specific seasonal variations depicting Fe-SOD isoform intensity being highest in summer season followed by rainy and winter seasons respectively. Native-PAGE enzyme profile elucidated the presence of four isoforms of catalase enzyme during summer season followed by three isoforms during winter and single isoform during summer seasons. Correlation matrix revealed that except phycocyanin which shows negative correlation with allophycocyanin, all other polar and non-polar solvent soluble photosynthetic pigments reveal positive correlation among themselves in response to temporal variations. 3D models of Fe-SOD and Mn-SOD in Oscillatoria sp. generated by homology modeling were validated to be of good quality. High conservation of all metal binding positions was also observed. The phylogenetic tree revealed that Planktothricoides sp. SR001 and Phormidiumam biguum were closest evolutionary homolog of Fe-SOD and Mn-SOD respectively in Oscillaroria sp. Thus, enzymatic and non-enzymatic antioxidants contribute jointly and specifically to combat oxidative stress thereby serving as biomarker of the response to various unfavorable temporal environmental cues prevailing at the natural habitat of Oscillatoria sp. The cyanobacterial antioxidative potential may be a crucial sustainable resource for several industrial processes exploiting biochemical and biotechnological applications.

Biosynthesis of Cylindrospermopsin in Cyanobacteria: Characterization of CyrJ the Sulfotransferase.

7-Deoxy-desulfo-cylindrospermopsin was purified at small-scale from the supernatant of a culture of the cyanobacterium Oscillatoria sp. PCC 10702. This metabolite was obtained in a pure form using a three-step chromatographic procedure, and its identity was confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). LC-MS quantification showed that this metabolite was excreted in the culture medium of Oscillatoria sp. PCC 10702. Isotopic incorporation studies using [2-13C,15N]glycine, a cylindrospermopsin precursor, and Oscillatoria sp. PCC 10702 cells showed that glycine was incorporated into 7-deoxy-desulfo-cylindrospermopsin, 7-deoxy-cylindrospermopsin, 7-epi-cylindrospermopsin, and cylindrospermopsin. The isotopic incorporation rate was consistent with the following metabolic flux: 7-deoxy-desulfo-cylindrospermopsin → 7-deoxy-cylindrospermopsin → 7-epi-cylindrospermopsin and cylindrospermopsin. We have cloned the cyrJ gene into an expression vector and overproduced the putative sulfotransferase CyrJ in Escherichia coli. The purified protein CyrJ catalyzed, in vitro, the transfer of a sulfonate group from 3'-phosphoadenosine-5'-phosphosulfate (PAPS) to 7-deoxy-desulfo-cylindrospermopsin to give 7-deoxy-cylindrospermopsin. Kinetic analysis afforded the following apparent constants: KMapp. (PAPS) = 0.12 μM, Vmaxapp. = 20 nM/min, KMapp. (7-deoxy-desulfo-cylindrospermopsin) = 0.12 μM, and KIapp. (7-deoxy-desulfo-cylindrospermopsin) = 4.1 μM. Preliminary data suggested that CyrJ catalyzed the reaction through a ternary-complex kinetic mechanism. All these data confirmed that CyrJ catalyzed a sulfotransfer during the penultimate step of the biosynthesis of cylindrospermopsin.

Lipid content, biomass density, fatty acid as selection markers for evaluating the suitability of four fast growing cyanobacterial strains for biodiesel production

Considering the glitches in making commercially realistic fuel, this research article has demonstrated the lipid accumulation in four fast growing, filamentous cyanobacterial strains. On day 26, the lipid content estimated was 6.7, 8.2, 10.2, and 9.4% from Phormidium sp. FW01, Phormidium sp. FW02, Oscillatoria sp. FW01, and Oscillatoria sp. FW02, respectively. Of the photosynthetically active radiation (PAR) tested, 2000 lx was found to higher biomass and lipid at about 1.83 g/L and 12.5%, respectively for Oscillatoria sp. FW01. Of <5 °C, 15 °C, 25 °C, 37–40 °C tested, 11.2% lipid was extracted from Oscillatoria sp. FW01 grown at 37–40 °C and pH did not make any changes in biomass and lipid content. The optimized abiotic conditions showed higher polar lipids about 75% in all the tested cyanobacteria and further, Oscillatoria sp. FW01 yielded 57% fatty acid methyl ester, which contains desirable fatty acids C 16:0, C 16:1, C18:1, C18:3 for high quality biodiesel.

Screening, molecular detection and hydrocarbon investigation of microalgae from paddy fields of Rasipuram area, Namakkal, Tamil Nadu

Microalgal biomass is an enhanced resource of energy and competent in meeting the universal demand for fuels in transports. It appeared as solitary of the most encouraging origin for the production of biofuel. The current study concerned the prevalence of Cyanobacteria, and Green algae from fifty water and algal sample of paddy fields of Rasipuram, Namakkal district, Tamil Nadu, India. An entirety of 262 cyanobacterial taxa of 25 genera delineating 7 families and 157 taxa of green algae of 23 genera depicting 15 families were documented. Among them, the dominant species reported were Oscillatoria sp. Synechocystis sp. Aphanocapsa sp. Scenedesmus sp. Spirogyra sp. and Chlamydomonas sp. Among the 25 genera of cyanobacteria, 6 were heterocystous and 19 were non-heterocystous. Among them, the dominant and fast-growing microalga was identified morphologically as Synechocystis sp. The microalgal growth rate, chlorophyll, carotenoids, and phycobilins were resolved. The microalga was executed with 16 s rRNA amplification, sequenced, and NCBI BLAST seek was accomplished, showed 99% similarity, and identified as S. aquatilis strain mn27. It was deposited in Genbank and KY120320 is the accession number. The tree of Phylogeny was inferred through the approach of Neighbour Joining with MEGA 5. The content of hydrocarbon in S. aquatilis was executed with GC-MS. The chief hydrocarbons were Dibutyl phthalate and Ethanol, 2,2′-oxybis-. Microalga is a gainful choice for the production of biofuel, while its accessibility, inexpensive, simple to cultivate, and curtail Carbon dioxide emission in the ambiance. Microalgal biomass is one of the greater resources of energy.

Exploration of fatty acid methyl esters (FAME) in cyanobacteria for a wide range of algae-based biofuels

Due to high demand in the industry field, fuel supply has been reduced due to overconsumption. Algae served as the most promising biofuels; Cyanobacteria is preferred as a material for producing biodiesel based on the comparative advantage. Cyanobacteria can produce high lipids profiles that can be used to produce biofuel or biodiesel. The present investigation aimed to identify the application of Cyanobacteria that have proposed lipid standards for the algae biofuel industry. Three main objectives are involved in these experiments: to isolate and identify different strains of Cyanobacteria, convert the lipid from microalgae into biodiesel through transesterification, and estimate the proposed lipid standard of Cyanobacteria for the algae biofuel industry. The microalgae involve isolated using a plankton net. The water sample is brought into the lab for the identification of Cyanobacteria. After the Cyanobacteria are identified, the Cyanobacteria undergo mass cultivation to ensure the biomass is enough for lipid screening. After lipid content is identified, the lipid in the Cyanobacteria is extracted and further transesterification process. The GC analysis showed the variation of fatty acid in this cyanobacterium, a saturated, monounsaturated, and polyunsaturated fatty acid. The study also revealed that hexadecanoic acid, pentadecanoic acid and pentadecanoic acid was found in Oscillatoria sp. Lipid screening can determine the quantity of lipid present in the Cyanobacteria to estimate the lipid content for biofuel production.

EFFECTIVENESS OF BACILLUS SPP. PRESS ON BLUE GREEN ALGAE (BGA) CAUSING OFF-FLAVOR IN CATFISH CULTIVATION

A problem that often occurred for the actor of catfish cultivation was an indication of smelly mud/dirt/muddy taste (off-flavors). Off-flavors were identified from chemical geosmin compound (GSM) and 2-Methyl Iso-borneol (MIB) produced by Cyanophyceae (Blue Green Algae or BGA) and actinomycetes. This soil odor compounds was soluble in water, into the body of fish through the gill and forwarded to the fatty tissue of fish, so that the fish meat was finally mud-smelly/dirt/musty. Probiotics was an attempt to reduce the compounds that caused off-flavors. The use of probiotics containing Bacillus spp. on feed could degrade organic matter through bioremediation digestive organs and environmental fish farming to minimize the accumulation of organic matter. The reduced of organic matter in waters on total organic odor, has impacted on the percentage of BGA as cause of mud-smelly in waters, especially for species Oscillatoria Sp. In this study, the researchers used Bacillus spp. to treat 10 ml/kg and 20 ml/kg of feed that can indirectly lower the percentage of BGA, Oscillatoria population Sp. and off-flavor in catfish meat as compared to controls.

Phycocyanin of marine Oscillatoria sp. inhibits lipoxygenase by protein-protein interaction-induced change of active site entry apace: A model for non-specific biofunctions of phycocyanins

An overview of the biological properties of phycocyanin (PC) amply illustrates that it may not have any specific functional feature towards any system at which it may elicit a specific function, but for the molecular interactions. Nevertheless, based on existing evidences, it is hypothesized that PC has more than one functional target with the interacting systems; therefore, it has diversity of effects. The mechanism of PC action remains elusive of a comprehensive idea. The present investigation focuses on the pro inflammatory enzyme, lipoxygenase (LOX) inhibiting property of PC purified from Oscillatoria sp. Enzyme kinetics studies show that the molecular composite of PC is required for its inhibition shown on LOX. Isothermal titration calorimetric study proves that one molecule of PC interacts with two molecules of LOX. Molecular dynamics simulation study pertaining to PC-LOX interactions shows it to be appropriate as a model to give molecular mechanistic insight into the varied biological properties of PC, demonstrated elsewhere in experimental studies including animal model studies. It explains that the PC-LOX interaction is of a function-freezing, protein-protein interaction in nature. The wide spectrum of properties of PC might be due to its function as a powerful protein hub showing non-specific protein-protein interactions.

Inhibition of Anabaena sp. and Oscillatoria sp. Using Probiotic Lactic Acid Bacteria

Water blooms are a serious environmental problem affecting fresh and marine ecosystem. Application of probiotic bacteria has been introduced as an emerging and eco-friendly tool to regulate or inhibit cyanobacterial blooms. In the present study, we have isolated and morphologically identified cyanobacteria from El Manzala Lake. Afterward, we examined the use of probiotic lactic acid bacteria MT2 (Lactobacillus sakei) isolated from Nile Tilapia (Oreochromis niloticus) intestine in controlling Anabaena sp. and Oscillatoria sp., isolated from El Manzala Lake. Measuring chlorophyll, phycocyanin and biomass concentration were conducted in a co-culture experiment between the selected cyanobacterial isolates and probiotic lactic acid bacteria (MT2). Chlorophyll content, phycocyanin content and biomass concentration of Anabaena sp., and Oscillatoria sp., were decreased significantly in the co-culture experiment with MT2 bacteria. Also, the microscopic examinations showed that MT2 bacterium was able to lysis and degrade the selected cyanobacterial cells under microscope. We concluded that the use of MT2 (Lactobacillus sakei) is potentially effective against some cyanobacteria especially Anabaena sp. and Oscillatoria sp.

In vitro screening of antimicrobial, antioxidant, cytotoxic activities, and characterization of bioactive substances from freshwater cyanobacteria Oscillatoria sp. SSCM01 and Phormidium sp. SSCM02

Cyanobacteria are rich sources of structurally novel and biologically active metabolites with antibacterial, antiviral, antifungal, and anticancer activities. The present study aimed to evaluate the antimicrobial, antioxidant, and toxicity potential of freshwater filamentous cyanobacterial species isolated from a freshwater source in Kancheepuram district and Thiruverumbur, Tamilnadu. Among the tested two cyanobacterial species, methanol-chloroform extracts of Oscillatoria sp. SSCM01 exhibits higher antibacterial activity than Phormidium sp. SSCM02. Oscillatoria sp. SSCM01 exhibited higher inhibition activity of bacterial growth at 31.2 μg/mL and 7.8 μg/mL as MIC value against Staphylococcus aureus, Salmonella typhi, respectively, and for Candida albicans at 125 μg/mL. Antioxidant activity of Oscillatoria sp. SSCM01 extract assessed by DPPH assay exhibited potent radical scavenging activity of 48% inhibition at 60 μg/mL concentration. Two cyanobacterial extracts exhibited significant activity against brine shrimp larvae (Artemia salina). The active fraction was subsequently analyzed by gas chromatography-mass spectrometry (GC-MS), bioactive compounds like hexadecanoic acid (66.3%), 1, 2-benzene dicarboxylic acid, and dibutyl phthalate were detected in Oscillatoria sp. SSCM01. Thus, our findings indicate that freshwater cyanobacteria Oscillatoria sp. SSCM01 has an inherent capability that might make it beneficial as a promising source of antimicrobial and antioxidant therapeutic agents.

Assessment of the ecological health of Geumchon stream using fish, benthic macroinvertebrate, and periphyton

An urban stream is currently being reconstructed as an ecological stream in Paju City, Korea. The diversity of fish, benthic macroinvertebrates, and periphyton in Geumchon stream was investigated, and the condition of the ecological health was assessed using the physicochemical condition of the water system. The goal is to use the data from this investigation to contribute to the establishment of policy for the conservation of Korea’s water environment. Samples of fish, benthic macroinvertebrates, and periphyton were collected from three sampling sites along the river a total of five times during the period October 2015 to June 2018 to determine the ecological structure of the Geumchon stream and its need for restoration. Samples of water and sediment were collected five times from five sampling sites for analysis of the physiochemical properties of the stream. Four families and ten species of fish were found with a total of 339 individuals. The fish found in the stream included the Carassius auratus, the Pseudorasbora parva, and the Oryzias sinensis, most of which are tolerant of water pollution. The relative richness index for Carassius auratus, Oryzias sinensis, Hemiculter eigenmanni, and Pseudorasbora parva was 52.5, 16.5, 12.7, and 12.4%, respectively. The predominant benthic macroinvertebrates observed at most sites were the Chironomidae sp. The dominant periphyton from 2015 to 2017 was the Nitzschia palea and in 2018 the Oscillatoria sp. Using the benthic macroinvertebrates index (BMI), the fish assessment index (FAI) and the trophic diatom index (TDI), the environmental condition ranged from moderate (C grade) to bad (D grade). The predominant species caught reflect the turbulent condition of the urban stream due to its reconstruction and the pollution. The biological indices (BMI, FAI, and TDI) and the physicochemical water items (BOD) were assessed separately to identify the quality of the water in the stream. The application of these biological assessments together with the chemical properties of the water can be used to provide a composite picture of the ecological health of a water system and to identify disturbances to its current condition.

In vitro screening of freshwater cyanobacterium oscillatoria sp For Anti-inflammatory activities

In vitro screening of freshwater cyanobacterium oscillatoria sp For Anti-inflammatory activities

The Effects of Effluent Discharged from Bottling Companies on Algal Composition in Kakuri Stream Kaduna, Nigeria

This study determined the impact of soft drink effluent on algal composition in Kakuri stream, Kaduna South Local Government Area, Kaduna. Limnological studies of soft drink effluent were carried out for a period covering wet and dry seasons across three (3) sampling points code-named Stations A, B and C. Some physio-chemical parameters were analysed using standard methods. A total of 43 species were observed belonging to 5 families. Chlorophyceae and Cyanophyceae were the most abundant families across the three (3) stations. The total flora count was high during the dry season, 1965 cells than wet season, 1071 cells. The most dominant species were Euglena sp., Microcystis sp. and Oscillatoria sp. The pH of the three stations was more alkaline (pH 8.1) but reduces slightly at stations B and C during the months of May (pH 5.2) and August (pH 6.5). The biological oxygen demand (BOD) was relatively high across the stations, dissolved oxygen was generally low except for some months (December at station A and January at station B) that had its dissolved oxygen values above 5.00 mg/l. Euglenophyceae showed positive correlation to conductivity and BOD, Chlorophyceae was positively correlated with BOD, Cyanophyceae showed positive relationship with BOD and dissolved oxygen, Charophyceae was positively correlated with dissolved oxygen, Bacillariophyceae showed positive correlation with pH, temperature, phosphorus, BOD and dissolved oxygen. Effluent discharge and farmland run-off passed into the water body supports growth of dominant species indicating organic pollution, thus, poses a threat to the environment over a long period of time.&#x0D; Keywords: Algae, Effluent, Biological oxygen demand, Dissolved oxygen.

Evaluation of heavy metal pollution in the Zayandeh-Rud River as the only permanent river in the central plateau of Iran.

Zayandeh-Rud River is the only permanent river in the central plateau of Iran. This river has been subject to an extensive discharge of wastewater and effluents from several point and nonpoint pollution sources. Accordingly, sediment quality of Zayandeh-Rud River in Varzaneh region, were studied. Algae and the sediment were sampled through 3 replications at 6 stations in the downstream after crossing through the Isfahan city and reaching Gavkhuni international wetland. Chlorophyll content and As, Pb, and Cd concentrations were measured in each sample Cladophora sp. and Oscillatoria sp. were identified using standard identification keys. The mean concentrations of metals in all stations exceeded background levels. Mean concentration of arsenic (162.9mg/kg) in the sediment is about 31 times more than the ISQG standard (5.9mg/kg) and considerably higher than the similar studies in Iran and other regions of the world. The mean concentration of As in algae samples is higher than the most polluted areas of the world. The mean concentration of Pb in the sediment (19.69mg/kg) is lower than the ISQGs standard (35mg/kg) and most of the studied river in north of Iran such as Chalous, Baboul-Rud, Gorgan-Rud (North), Khiav (North West), and Anzali wetland. The mean concentration of Cd in the sediment (2.11mg/kg) is significantly higher than ISQG standard (0.6mg/kg and some north highly polluted wetlands of Iran such as Anzali. There is a significant positive correlation between the mean concentrations of As and Pb in the sediment and Cladophora sp. tissue, and a negative one between the mean concentration of Pb in the sediment and chlorophyll b/a. There are significant negative correlations between the mean concentration of As in the sediment and chlorophyll a, and the total chlorophyll concentration in Oscillatoria sp. The results of Muller index indicate that the concentrations of Pb, Cd, and As in all stations occur in the Unpolluted, Moderate/Heavy, and Heavy/Extreme groups, respectively. Degree of contamination and modified degree of contamination show very high degree of pollution in the studied area. RI in all the stations showed very high ecological risk. The bioaccumulation factor for all metals in both algae is less than one. So, these two species may not be described as heavy metal accumulators. This study is an alarm for the Zayandeh-Rud River as the most important freshwater source for the Iranian Plateau. Graphical abstract.

Lab-scale degradation of leather industry effluent and its reduction by Chlorella sp. SRD3 and Oscillatoria sp. SRD2: a bioremediation approach

The present study focuses on treatment of tannery effluent samples using microalgae and isolated cyanobacteria. Different concentrations of both the effluent samples were treated with the algal isolates and a highest biomass of 0.295 g/l was attained in 50% of concentration on the 12th day in BHEL site. The biomass production in Walajapet site was found to be 0.387 g/l in the effluent treated with 50% of algae. The treated effluent was tested for growth and chlorophyll content was estimated, Chlorella sp. SRD3 showed higher chlorophyll content. The 50% treatment was processed at large-scale treatment in lab and biomass yield of 0.65 ± 0.04 g/l was achieved in BHEL site and 0.49 ± 0.028 g/l in Walajapet site. The treatment led to higher reduction rates in BOD and COD levels in treated effluents. The BOD in effluent from BHEL site was reduced to 83.41% and that from Walajapet site showed 87.46% reduction, whereas the COD values also showed 78% reduction. Based on the results, effluent sample serves as a medium for growth and bioremediation of tannery effluents by microalga, Chlorella sp. SRD3 revealed promising results which may prove efficient in the near future.

Determining the Binding Capacities of Cr (VI) and Zn (II) Ions of Oscillatoria sp.

This study aimed to determine the removal capacity for Cr (VI) and Zn (II) ions from high concentration of aqueous solutions by using Oscillatoria microalgae. In the biosorption process, live and dead Oscillatoria cells were exposed for 24 hours to Cr and Zn metals of different concentrations (2.5, 5 and 10 mg/L). In addition, chlorophyll-a analysis have been made to examine the effects on cell metabolism of chromium and zinc metals. The best metal removal percentages was obtained; of chromium ion is 46.74% with dead cells and for zinc ion 82.53% with living cells. Chlorophyll-a analysis shows that when the metals separately applied on Oscillatoria cells, chlorophyll-a content of organism increase but when metals together applied decrease of chlorophyll-a content was observed. For this study, Freundlich model best fitted the data for two metal ions with 1/n value &amp;lt;1. This study revealed that Oscillatoria cells were an effective adsorbent for removal of the two heavy metals, especially Zn ions from aqueous solutions due to its high efficiency of Zn adsorption. It shows that it is a kind of potential for this heavy metal removal operations.

What Triggers the Annual Cycle of Cyanobacterium Oscillatoria sp. in an Extreme Environmental Sulfide-Rich Spa?

A seasonal cycle of sulfide, nitrate, phosphate, ammonium, chlorophyll a (Chl a) and Oscillatoria sp. abundance (&lt;100 μm), as well as the relative contribution of taxonomic phytoplanktonic groups (cyanobacteria, green algae, cryptomonads, diatoms and dinoflagellates) to total Chl a were measured by fluorometric measurements at La Hedionda sulfide-rich spa (southern Spain). Fluorometry determined that cyanobacteria Chl a concentration correlated positively with the abundance of Oscillatoria sp. Aggregates at 45–100 μm equivalent spherical diameter (ESD) and was used as an indicator of Oscillatoria sp. Abundance, including for aggregates &lt;45 and &gt;100μm (ESD). In addition, air temperature, radiation and precipitation were downloaded from meteorological databases. In agreement with the meteorological annual cycle observed in air temperature, radiation and precipitation, sulfide concentration at La Hedionda Spa shows an annual cycle with concentrations around 40 μM in winter and up to 200 μM in the dry summer period. Phytoplankton composition was dominated by cyanobacteria (mainly Oscillatoria sp.), but other groups were also represented (green algae, cryptomonads, diatoms and dinoflagellates), although they remained constant throughout the year (median Chl a &lt; 0.2 μg L−1). Cyanobacteria, in contrast, showed an annual cycle with a significantly higher median in summer (Chl a = 1.6 μg L−1) than in winter (Chl a = 0.4 μg L−1). No linear relationship between nutrients and cyanobacteria concentration was observed, but an optimum curve of cyanobacteria concentration to sulfide concentration was fitted through a general additive model (GAM). The four-fold increase of cyanobacteria concentration under exposition of an elevated sulfide concentration can be due to higher growth rates at elevated sulfide concentrations reported for an Oscillatoria sp. strain isolated during the same annual cycle at La Hedionda and we suggest that the selective agent, sulfide, positively triggers Oscillatoria sp. proliferation in summer. According to our findings, the Oscillatoria sp. population of La Hedionda not only is sulfide-resistant, but requires sulfide in its optimal niche.