Growths of
Lyngbya limnetica
and
Oscillatoria obscura
were investigated at varying pH, light intensity, temperature, and trace element concentration with a view to optimize these parameters for ...obtaining the maximum carbohydrate content. The maximum growth for both strains was obtained at pH 9.0 and temperature 20 ± 3 °C using a light intensity of 68.0 μmol m
−2
s
−1
with continuous shaking. Growth under the nitrogen starvation condition affected the carbohydrate content more compared to the phosphorus starvation, and maximum concentrations were found as 0.660 and 0.621 g/g of dry biomass for
L. limnetica
and
O. obscura
, respectively. Under the optimized nitrogen-rich conditions, the specific growth rates for the two strains were found to be 0.187 and 0.215 day
−1
, respectively. The two-stage growth studies under nitrogen-rich (stage I) followed by nitrogen starvation (stage II) conditions were performed, and maximum biomass and carbohydrate productivity were found as 0.088 and 0.423 g L
−1
day
−1
for
L. limnetica
. This is the first ever attempt to evaluate and optimize various parameters affecting the growth of cyanobacterial biomass of
L. limnetica
and
O. obscura
as well as their carbohydrate contents.
Utilization of cyanobacteria for remediation of pollutants and thereby large production of microalgae for sustainable biofuel production is a practicable option. In the present study, a ...cyanobacterial consortium of Oscillatoria subbrevis and Gloeocapsa atrata, collected from East Kolkata Wetland, a “Wetland of International Importance”, has been used for removal of Cr(VI) from simulated wastewater and the effect of Cr(VI) on biomass production was investigated. The Monod model has been used to depict growth kinetics of the cyanobacterial consortium in pure media. Maximum specific growth rate and saturation constant have been found to be 0.1562 day–1 and 0.024 g/L, respectively. The kinetic study on Cr(VI) removal shows that biomass and lipid production are more when the cyanobacterial consortium have been cultured in wastewater containing Cr(VI) than in pure media. The growth of the cyanobacterial consortium in relation to Cr(VI) removal as well as lipid production has been optimized using response surface methodology. Optimum metal removal has been achieved when initial Cr(VI) concentration, pH, inoculum size, and time are 11.08 ppm, 9.0, 0.39 g, and 9 days, respectively.
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•Fungal cellulase production using residual algal biomass has been performed.•Significantly enhanced cellulase production catalyzed by NiFe2O4 NPs.•Cellulase enzyme exhibits better ...thermal and pH stability catalyzed by NiFe2O4 NPs.•High sugar (42.40 g/L) is yielded in just 12 h due to catalytic effect of NiFe2O4 NPs.•Cumulative hydrogen ~ 1820 mL/L with optimum production rate of 19.92 mL/L/h in 24 h.
The present study reports nickel ferrite nanoparticles (NiFe2O4 NPs) induced enhanced production of crude cellulase enzyme using residual algal biomass of cyanobacteria Lyngbya limnetica as substrate. It is noticed that the residual algal substrate and NiFe2O4 NPs mediated crude cellulase exhibits nearly 2.5 fold enhanced filter paper activity after 72 h along with better efficiency in terms of pH and thermal stability as compared to the control system. Further, NiFe2O4 NPs mediated crude cellulase enzyme was employed for the enzymatic hydrolysis of rice straw to produce sugar hydrolyzate. Subsequently, using bacterial strains Bacillus subtilisPF_1 the cumulative hydrogen ~ 1820 mL/L has been produced under the dark fermentation.
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•Cyanobacterial hydrolysate is a good source of fermentable sugar for biobutanol.•Addition of glucose (10.0 g/L) increased biobutanol production by 55.0%.•Use of L. limnetica biomass ...(from two-stage growth) improves productivity by 37.0%.•Use of 1.0L agitated bioreactor improves biobutanol production by 9.0%.
The potential of hydrolysates of cyanobacteria Lyngbya limnetica and Oscillatoria obscura for biobutanol production was evaluated under varying operating conditions using Clostridium beijerinckii ATCC 35702 culture as the fermenting microrganism. Effects of various process parameters affecting the biobutanol production were investigated using glucose as the C-source. The maximum biobutanol productivity of 1.565 g/L/d was obtained with L. limnetica biomass hydrolysate supplemented with 10.0 g/L of glucose under the best conditions in batch mode. The large biobutanol production (8.873 g/L) was obtained with glucose supplemented hydrolysate while the highest yield (0.421 g/g sugar) was found with pure cyanobacterial hydrolysate indicating its industrial feasibility. The hydrolysates prepared from biomass of L. limnetica and O. obscura grown following a two-stage protocol, were utilized for the first time for biobutanol fermentation and nearly 33.0 and 31.0% increased biobutanol productivities, respectively, were obtained under the best operating conditions. Results of the agitated bioreactor studies were analysed by fitting the data into the Mercier’s kinetic model and the high value of regression coefficients (≥0.93) indicated excellent agreement between the experimental values and model predictions. The results were also used to present a metabolic pathway and carry out a mass balance analysis for biobutanol fermentation.
The present work aims at evaluation of the potential of cyanobacterial biomass to remove Cu(II) from simulated wastewater. Both dried and carbonized forms of
Lyngbya majuscula
, a cyanobacterial ...strain, have been used for such purpose. The influences of different experimental parameters viz., initial Cu(II) concentration, solution pH and adsorbent dose have been examined on sorption of Cu(II). Kinetic and equilibrium studies on Cu(II) removal from simulated wastewater have been done using both dried and carbonized biomass individually. Pseudo-second-order model and Langmuir isotherm have been found to fit most satisfactorily to the kinetic and equilibrium data, respectively. Maximum 87.99 and 99.15 % of Cu(II) removal have been achieved with initial Cu(II) concentration of 10 and 25 mg/L for dried and carbonized algae, respectively, at an adsorbent dose of 10 g/L for 20 min of contact time and optimum pH 6. To optimize the removal process, Response Surface Methodology has been employed using both the dried and carbonized biomass. Removal with initial Cu(II) concentration of 20 mg/L, with 0.25 g adsorbent dose in 50 mL solution at pH 6 has been found to be optimum with both the adsorbents. This is the first ever attempt to make a comparative study on Cu(II) removal using both dried algal biomass and its activated carbon. Furthermore, regeneration of matrix was attempted and more than 70% and 80% of the adsorbent has been regenerated successfully in the case of dried and carbonized biomass respectively upto the 3rd cycle of regeneration study.
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•Co-fermentation of residual algal biomass and glucose under the influence of Fe3O4 NPs.•Fe3O4 NPs leads ∼ 37.14 % higher cumulative H2 as compared to control at 37 °C.•∼ 11.28 % ...higher hydrogen production at optimum temperature in presence of Fe3O4 NPs.•Evaluates hydrogen production at different pH in presence of Fe3O4 NPs.•Potential of nanomaterials induced enhanced hydrogen production using co-fermentation.
The present study reports Fe3O4 nanoparticles (Fe3O4 NPs) induced enhanced hydrogen production via co-fermentation of glucose and residual algal biomass (cyanobacteria Lyngbya limnetica). A significant enhancement of dark fermentative H2 production has been noticed under the influence of co-fermentation of glucose and residual algal biomass using Fe3O4 NPs as catalyst. Further, using the optimized ratio of glucose to residual algal biomass (10:4), ∼ 37.14 % higher cumulative H2 has been recorded in presence of 7.5 mg/L Fe3O4 NPs as compared to control at 37 °C. In addition, under the optimum conditions glucose to residual algal biomass ratio (10:4) presence of 7.5 mg/L Fe3O4 NPs produces ∼ 937 mL/L cumulative H2 in 168 h at pH 7.5 and at temperature 40 °C. Clostridum butyrium, employed for the dark fermentation yielded ∼ 7.7 g/L dry biomass in 168 h whereas acetate (9.0 g/L) and butyrate (6.2 g/L) have been recorded as the dominating metabolites.
Biohydrogen production using renewable sources has been regarded as one of the most sustainable ways to develop low-cost and green production technology. In order to achieve this objective, herein ...biohydrogen production has been conducted using the combination of untreated secondary sewage sludge (Sss), algal biomass hydrolyzate (Abh), graphene oxide (GO) and bacterial consortia that forms a granular system. Thus, naturally formed granular system produced cumulative H2 of 1520 mL/L in 168 h with the maximum production rate of 13.4 mL/L/h in 96 h at initial pH 7.0, and optimum temperature of 37 °C. It is noticed that the combination of Abh, Sss and GO governed medium showed 42.05 % higher cumulative H2 production along with 22.71 % higher production rate as compared to Abh and Sss based H2 production medium. The strategy presented herein may find potential applications for the low-cost biohydrogen production using waste biomasses including Sss and Abh.
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•Aerobic granular sludge (AGS) is used to produce biohydrogen via dark fermentation.•AGS is based on sludge, algal biomass, bacterial consortia and graphene oxide (GO).•GO supported improved dark fermentative biohydrogen have been performed using AGS.•GO supported system showed 42.05 % higher cumulative H2 production compared to control.•Strategy may be highly potential to produce biohydrogen using waste biomass.
Present investigation was done to evaluate various algal genera found in water bodies of Varanasi city. The potential of any biomass for biofuels (bioalcohols, biohydrogen, etc.) production depends ...on the quantity of extractable sugar present in it. Acid (H
2
SO
4
) and alkali (NaOH) pretreatment were performed, and H
2
SO
4
was chosen due to its nearly double yield as compared with alkaline pretreatment. Response surface methodology was utilized for the optimization of operating parameters such as treatment temperature, time, and acid concentration. Sugar yield up to 0.33 g/g of dry biomass was obtained using cyanobacterial biomass of Lyngbya limnetica, at 100°C, 59.19 min, and H
2
SO
4
concentration of 1.63 M.
The present study reports Fe
O
nanoparticles (Fe
O
NPs) induced enhanced hydrogen production via co-fermentation of glucose and residual algal biomass (cyanobacteria Lyngbya limnetica). A significant ...enhancement of dark fermentative H
production has been noticed under the influence of co-fermentation of glucose and residual algal biomass using Fe
O
NPs as catalyst. Further, using the optimized ratio of glucose to residual algal biomass (10:4), ∼ 37.14 % higher cumulative H
has been recorded in presence of 7.5 mg/L Fe
O
NPs as compared to control at 37 °C. In addition, under the optimum conditions glucose to residual algal biomass ratio (10:4) presence of 7.5 mg/L Fe
O
NPs produces ∼ 937 mL/L cumulative H
in 168 h at pH 7.5 and at temperature 40 °C. Clostridum butyrium, employed for the dark fermentation yielded ∼ 7.7 g/L dry biomass in 168 h whereas acetate (9.0 g/L) and butyrate (6.2 g/L) have been recorded as the dominating metabolites.
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