Optimization of Cultivation Conditions of Native Microalga Scenedesmus quadricauda and Evaluation of Lipids for Enhanced Biodiesel Production.

Biofuels are considered to be among the primary alternatives to the use of fossil fuels. These fuels, made from feedstock or waste raw materials, have the advantage of being renewable and contributing much less to global warming. Microalgae are a promising biodiesel source. Microalgae, unlike traditional crops that are now used to make commercialized biodiesel, may be grown on non-agricultural land and has a greater capacity for growth and yield. Cultivation has been considered as a critical stage in the generation of biofuels. The goal of the present study is to learn that Scenedesmus quadricauda has a potential for biodiesel production in the near future. Optimization studies revealed that BG-11 medium, temperature of 25 °C, pH 7.0, glucose and sucrose (as carbon sources), static condition (for lipid accumulation) & shaking condition (for biomass yield), cultivation days of 18, 21, and 24 day, NaNO3 dosing of 1.0 mM followed by 0.8 mM (on 5th day of cultivation), 3% yeast extract dosing, 3000 lx light intensity, photoperiod cycles of 24L/0D (for biomass yield) and 18L/6D (for lipid production) and 10 mM concentration of NaCl (salinity stress) can be regarded as best suited physio-biochemical parameters for efficient biomass and lipid yield from S. quadricauda. FTIR indicated presence of various stretching of carbohydrates and lipids that again is supporting biodiesel production capability of S. quadricauda. SEM showed that cells of S. quadricauda under stress conditions became fragmented separated from coenobium and were not so compactly arranged. Present optimization studies along with Nile red fluorescence, FTIR and SEM revealed that S. quadricauda could be a suitable candidate to produce good quality biofuel and that also in stress conditions.

Polycyclic aromatic hydrocarbons in sewage-irrigated vegetables from industrial cities in Haryana, India.

The majority of Indians consume a lot of vegetables because of their health advantages. High concentrations of polycyclic aromatic hydrocarbons (PAHs) in vegetables may be seriously harmful to consumers' health. The method for identifying and measuring 16 USEPA polycyclic aromatic hydrocarbons (PAHs) in samples of sewage-irrigated vegetables from three industrial cities in Haryana, India, is described in this research. Ultrasonication, liquid-liquid extraction using n-hexane as a solvent, clean-up using a Florisil column, and reversed-phase high-performance liquid chromatography with a UV detector were all included in the process. The PAHs were successfully linearized (R2 > 0.99) at various doses. Results for PAH recovery ranged from 90 to about 100%. The limit of quantification was 0.002-0.580, and the limit of detection was 0.0006-0.174 µgkg-1. Data indicated that the highest mean concentrations of ∑16 PAHs were detected in Spinach (123.36 µgkg-1), in carrot (105.09 µgkg-1), and in cucumber (63.40 µgkg-1) among leafy, underground, and fruity vegetables, respectively.

A panoramic view of technological landscape for bioethanol production from various generations of feedstocks.

Bioethanol is an appropriate alternate energy option due to its renewable, nontoxic, environmentally friendly, and carbon-neutral nature. Depending upon various feedstocks, bioethanol is classified in different various generations. First-generation ethanol created a food vs fuel problem, which was overcome by second-generation, third-generation and fourth-generation ethanol. The considerable availability of lignocellulosic biomass makes it a suitable feedstock, however, its recalcitrant nature is the main hurdle in converting it to bioethanol. The present study gives a comprehensive assessment of global biofuel policies and the current status of ethanol production. Feedstocks for first-generation (sugar and starch-based), second-generation (lignocellulosic biomass and energy crops), third-generation (algal-based) and fourth-generation (genetically modified algal biomass or crops) are discussed in detail. The study also assessed the process for ethanol production from various feedstocks, besides giving a holestic background knowledge on the bioconversion process, factors affecting bioethanol production, and various microorganisms involved in the fermentation process. Biotechnological tools also play a pivotal role in enhancing process efficiency and product yield. In adddition, most significant development in the field of genetic engineering and adaptive evolution are also highlighted.

Global biofuels policies on bioethanol production were presentedTechnological integrations of 1G, 2G, 3G and 4G bioethanol were discussedVarious factors affecting bioethanol production were mentionedTechno-economic analysis and LCA of bioethanol production are discussed.

Upgrading of microalgal consortia with CO2 from fermentation of wheat straw for the phycoremediation of domestic wastewater.

Algae have been considered as a best feedstock for combating CO2. In the present study, two mixed microalgal cultures i.e. MAC1 and MAC2 were evaluated in batch mode with an extraneous supply of CO2 from the fermentation of wheat straw. Both the mixed cultures displayed promising CO2 sequestration potentials of 287 and 263 mg L-1d-1, respectively. The removal efficiencies in terms of ammonium, phosphate, chemical oxygen demand, and nitrate were found to be 87%, 78%, 68% and 65%, respectively. Enriching the tolerance of the microalgal consortia to CO2 supply and wastewater as the nutrient source significantly enhanced the lipid production for both the microalgae consortia. Lipid contents of MAC1 and MAC2 were observed to be 12.29 & 11.37%, respectively while the biomass yield from both the consortia was 0.36 g L-1. Total chlorophyll and protein contents of MAC1 and MAC2 were 14.27 & 12.28 µgmL-1 and 0.13 & 0.15 mgmL-1, respectively. Both the consortia found to have significant potential for CO2 sequestration, wastewater remediation and biofuel production.

An overview on bioethanol production from lignocellulosic feedstocks.

Lignocellulosic ethanol has been proposed as a green alternative to fossil fuels for many decades. However, commercialization of lignocellulosic ethanol faces major hurdles including pretreatment, efficient sugar release and fermentation. Several processes were developed to overcome these challenges e.g. simultaneous saccharification and fermentation (SSF). This review highlights the various ethanol production processes with their advantages and shortcomings. Recent technologies such as singlepot biorefineries, combined bioprocessing, and bioenergy systems with carbon capture are promising. However, these technologies have a lower technology readiness level (TRL), implying that additional efforts are necessary before being evaluated for commercial availability. Solving energy needs is not only a technological solution and interlinkage of various factors needs to be assessed beyond technology development.

Microalgal consortia for municipal wastewater treatment - Lipid augmentation and fatty acid profiling for biodiesel production.

The present study investigates the phycoremediation potentials of two microalgal consortia (MAC1 and MAC2) for treating sewage water and producing biomass with high lipid, protein and chlorophyll contents. During the study, the microalgal strains were tested for lipid enhancement, biomass production and contaminant removal from wastewater. The microalgal consortia showed prolific growth in wastewater with 75% dilution and accumulated higher lipid content of 31.33% dry cell weight in MAC1. The maximum biomass (50% diluted wastewater) for both the consortia was 1.53 and 1.04 gL-1. Total chlorophyll (19.17-25.17 µg mL-1) and protein contents (0.12-0.16 mg mL-1) for both the consortia were found to be maximum in 75 WW. MAC1 was capable of removing 86.27% of total organic carbon and 87.6% of chemical oxygen demand. Approximately, 94% of nitrate and phosphate contents were removed from the initial contents of wastewater. Heavy metal removal efficiency was also found to be better and showed 85.06% Cu, 75.2% Cr, 98.2% Pb, and 99.6% Cd removal by the algal consortia. Pyrolytic decomposition of algal consortia was observed using thermogravimetric analysis. The stepwise decomposition of algae indicated distinct losses of functional groups. The gas chromatography-mass spectrometric analysis revealed the majority of saturated fatty acids followed by monounsaturated and polyunsaturated fatty acids. Thus, the present study proved that both the consortia show tremendous potential for the treatment of domestic wastewaters with successive lipid enhancement for biodiesel production.

Screening and enrichment of high lipid producing microalgal consortia.

Lipid content is the main parameter for the evaluation of microalgae towards biodiesel production. The present study was aimed at the screening of desirable algal consortia based on lipid content for further processing into biofuel. Twenty different algal consortia were investigated for lipid content qualitatively by Nile Red and quantitatively by gravimetric method and FTIR. Nile Red is used as a fluorophore for physically characterizing the lipid body in algal cultures. The yellow fluorescence in all the samples confirmed the presence of lipid content when observed under a fluorescent microscope. Lipid contents of algal consortia estimated by gravimetry varied from 3.53-16.21%, which was higher than that assessed by FTIR analysis. FTIR spectroscopy can be used for the quantitative estimation of lipid content, protein and carbohydrate concentration. FTIR analysis of the samples revealed the presence of lipid content by virtue of methylene and methyl stretching peaks at 2800-3000 cm-1. The appearance of stretching vibrations at 1600-1700 cm-1 and 1000-1200 cm -1 obtained by FTIR spectra confirmed the presence of protein contents and carbohydrate, respectively in all the samples. Two algal consortia SM 4 and SM13 were screened out on the basis of high lipid concentration. These algal samples can be further optimized for enhanced biofuel production.

Physico-chemical pretreatment and enzymatic hydrolysis of cotton stalk for ethanol production by Saccharomyces cerevisiae.

The aim of this work was to study the physico-chemical pretreatment and enzymatic hydrolysis of cotton stalk for ethanol production by Saccharomyces cerevisiae. Firstly, factors affecting pretreatment were screened out by Plackett-Burman design (PBD) and most significant factors were further optimized by Box-Behnken design (BBD). As shown by experimental study, most significant factors were FeCl3 concentration (FC), irradiation time (IT) and substrate concentration (SC) affecting pretreatment of cotton stalk among all studied factors. Under optimum conditions of pretreatment FC 0.15mol/l, IT 20min and SC 55g/l, the release of reducing sugar was 6.6g/l. Hydrolysis of pretreated cotton stalk was done by crude on-site produced enzymes and hydrolysate was concentrated. Ethanol production by Saccharomyces cerevisiae using concentrated cotton stalk hydrolysate was 9.8gp/l, with ethanol yield 0.37gp/gs on consumed sugars. The data indicated that microwave FeCl3 pretreated cotton stalk hydrolyses by crude unprocessed enzyme cocktail was good, and ethanol can be produced by fermentation of hydrolysate.

Syntrophic association and performance of Clostridium, Desulfovibrio, Aeromonas and Tetrathiobacter as anodic biocatalysts for bioelectricity generation in dual chamber microbial fuel cell.

Anode chamber of a dual chamber microbial fuel cell (MFC) having raw landfill leachate was inoculated with consortium of sulphate-reducing bacteria (SRB) and sulphide-oxidizing bacteria (SOB) to study the phylogenetic architecture, function and mutualism of anolyte community developed in the reactor. Enriched microbial community was analysed with the help of Illumina MiSeq and indicated the dominance of Firmicutes (41.4%), Clostridia (36.4%) and Clostridium (12.9%) at phylum, class and genus level, respectively. Clostridium was associated with fermentation as well as transfer of electrons to the electrode mediated by ferredoxin. Desulfovibrio (6.7%), Aeromonas (6.6%) and Tetrathiobacter (9.8%) were SRB-SOB associated with direct electron transfer to the electrode. Community analysis disclosed a syntrophic association among novel Firmicutes and Proteobacteria species for bioelectricity generation and degradation of organic matter. Complete removal of chemical oxygen demand was observed from landfill leachate within 3 days of inoculation. Lower oxidative slope and polarization resistance revealed from Tafel analysis backed the feasibility of electron transfer from microbes to anodic electrode and thus development of efficient anode-respiring community. Following enrichment and stabilization of the anodic community, maximum power density achieved was 9.15 W/m3 and volumetric current density was 16.17 A/m3. Simultaneous feeding with SRB-SOB and landfill leachate led to the enrichment of a novel, mutually interdependent microbial community capable of synchronized bioremediation of effluents rich in carbon, sulphate, nitrate and aromatic compounds.

Evaluation of Pseudomonas aeruginosa an innovative bioremediation tool in multi metals ions from simulated system using multi response methodology.

Under certain conditions bacteria can act as a good biosorbent towards heavy metals in simultaneous removal from effluents. The present study explores overlay plots of multi response surface methodology for simulated wastewater treatment potential. Pseudomonas aeruginosa was used for bioremediation of metallic ions, where removal of Cd (80-90%), Mn (85-90%), Fe (50-55%), Cr (70-75%) can be achieved by fixing the pH, oxidation reduction potential (mV) and one of the metallic constituent in the simulated effluent. The metal ions Cd and Cr (T), Fe and ORP (mV) are relatively closely located to each other in the loading plot indicating co-variance between these components. However Cr(VI) transformation and Mn removal are distantly placed in the bi-plot indicating the existed significant difference. Elevated reductase enzyme activity (31.75 µg/minmg) observed in the isolate showing the ability to effectively reduce metals ions.

Synergism of Pseudomonas aeruginosa and Fe0 for treatment of heavy metal contaminated effluents using small scale laboratory reactor.

In this study Pseudomonas aeruginosa a metal tolerant strain was not only applied for heavy metal removal but also to the solublization performance of the precipitated metal ions during effluent treatment. The synergistic effect of the isolate and Fe(0) enhanced the metal removal potential to 72.97% and 87.63% for Cr(VI) and cadmium, respectively. The decrease in cadmium ion removal to 43.65% (aeration+stirring reactors), 21.33% (aerated reactors), and 18.95% (without aerated+without stirring) with an increase in incubation period not only indicate the presence of soluble less toxic complexes, but also help in exploration of the balancing potential for valuable metal recovery. A relatively best fit and significant values of the correlation coefficient 0.912, 0.959, and 0.9314 for mixed effluent (Paint Industry effluent+CETP Wazirpur, effluent), CETP, Wazirpur, and control effluents, respectively, indicating first-order formulation and provide a reasonable description of COD kinetic data.

Optimization of enzymatic hydrolysis of pretreated rice straw and ethanol production.

Cellulase, Tween 80, and ß-glucosidase loading were studied and optimized by response surface methodology to improve saccharification. Microwave alkali-pretreated rice straw used as substrate for onsite enzyme production by Aspergillus heteromorphus and Trichoderma reesei. The highest enzymatic hydrolysis (84%) was obtained from rice straw at crude enzyme loading of 10 FPU/gds of cellulase, 0.15% Tween 80, and 100 international unit/g dry solids of ß-glucosidase activities. Enzymatic hydrolyzate of pretreated rice straw was used for ethanol production by Saccharomyces cerevisiae, Scheffersomyces stipitis, and by co-culture of both. The yield of ethanol was 0.50, 0.47, and 0.48 g(p)/g(s) by S. cerevisiae, S. stipitis, and by co-culture, respectively, using pretreated rice straw hydrolyzate. The co-culture of S. cerevisiae and S. stipitis produced 25% more ethanol than S. cerevisiae alone and 31% more ethanol than S. stipitis alone. During anaerobic fermentation 65.08, 36.45, and 50.31 µmol/ml CO(2) released by S. cerevisiae, S. stipitis, and by co-culture, respectively. The data indicated that saccharification efficiency using optimized crude enzyme cocktail was good, and enzymatic hydrolyzate could be fermented to produce ethanol.

Enzymatic hydrolysis optimization of microwave alkali pretreated wheat straw and ethanol production by yeast.

Microwave alkali pretreated wheat straw was used for in-house enzyme production by Aspergillusflavus and Trichodermareesei. Produced enzymes were concentrated, pooled and assessed for the hydrolysis of pretreated wheat straw. Factors affecting hydrolysis were screened out by Placket-Burman design (PBD) and most significant factors were further optimized by Box-Behnken design (BBD). Under optimum conditions, 82% efficiency in hydrolysis yield was observed. After the optimization by response surface methodology (RSM), a model was proposed to predict the optimum value confirmed by the experimental results. The concentrated enzymatic hydrolyzate was fermented for ethanol production by Saccharomyces cerevisiae, Pichia stipitis and co-culture of both. The yield of ethanol was found to be 0.48 g(p)/g(s), 0.43 g(p)/g(s) and 0.40 g(p)/g(s) by S. cerevisiae, P. stipitis and by co-culture, respectively, using concentrated enzymatic hydrolyzate. During anaerobic fermentation 42.31 µmol/mL, 36.69 µmol/mL, 43.35 µmol/mL CO(2) was released by S. cerevisiae, P. stipitis and by co-culture, respectively.

Enhanced saccharification of rice straw and hull by microwave-alkali pretreatment and lignocellulolytic enzyme production.

In this study, statistical design of experiments was employed to plan experiments and optimize the microwave-alkali pretreatment of rice straw and hulls. Process parameters important in pretreatment of biomass were identified by a Plackett-Burman design and the parameters with significant effects were optimized using a box-behnken design (BBD). Experimental results show that alkali concentration (AC), irradiation time (IT) and substrate concentration (SC) were main factors governing the saccharification of rice straw and hulls. Optimum conditions of pretreatment were AC 2.75%, IT 22.50 min and SC 30 g/L, as optimized by BBD. The growth and production of lignocellulolytic enzymes from Aspergillus heteromorphus, solid state fermentation (SSF) was performed using rice straw and hulls pretreated under optimum conditions. Cellulases and xylanase reached the highest enzyme activity at 6th day of fermentation while maximum manganese peroxidase (MnP) and laccase activity occurred at 12th day.

Removal of sulphate, COD and Cr(VI) in simulated and real wastewater by sulphate reducing bacteria enrichment in small bioreactor and FTIR study.

The present study was conducted to investigate the chromium(VI), COD and sulphate removal efficiency from aqueous solution and treatment of real effluent (CETP) in a small scale bioreactor using sulphate reducing bacteria consortium. Effect of different hydraulic retention times (HRTs), initial metal concentrations, various carbon sources and temperatures were studied on removal of chromium(VI), COD and sulphate. Maximum chromium(VI) and sulphate removal was found to be 96.0% and 82.0%, respectively, at initial concentration of 50 mg l(-1) using lactate as carbon source. However, highest COD removal was 36.2% in medium containing fructose as the carbon source and electron donor. NADH dependent chromate reductase activity was not observed which indicated the anaerobic consortium. Initially consortium medium with a strong negative oxidation reduction potential indicated the reducing activity. The FTIR spectrum of the sulphate reducing bacteria consortium clearly shows the existence of the sulphate ions and signifies that sulfate reducing bacteria have used sulfate during the growth phase.

Laccase production by Aspergillus heteromorphus using distillery spent wash and lignocellulosic biomass.

Laccase is among the major enzymes which plays an important role in ligninolytic system of fungi. Laccase production by Aspergillus heteromorphus was studied using anaerobically treated distillery spent wash (ADSW) and lignocellulosic biomass. Lignocellulosic biomass (rice straw, wheat straw and sugarcane bagasse) generated during biomass processing leads to solid waste and distillery spent wash is unwanted liquid waste produced by distilleries, both causes environmental pollution. Two mineral media and anaerobically treated distillery spent wash medium was tested for laccase production. Enzyme production in various media and in presence and absence of lignocellulosic biomass supplements showed that anaerobically treated distillery spent wash medium was a better laccase inducer medium than the mineral media. Addition of lignocellulosic biomass enhances laccase production and highest laccase activity was obtained in 5% anaerobically treated distillery spent wash medium with rice straw.

Biosorption optimization of lead(II), cadmium(II) and copper(II) using response surface methodology and applicability in isotherms and thermodynamics modeling.

The present study was carried out to optimize the various environmental conditions for biosorption of Pb(II), Cd(II) and Cu(II) by investigating as a function of the initial metal ion concentration, temperature, biosorbent loading and pH using Trichoderma viride as adsorbent. Biosorption of ions from aqueous solution was optimized in a batch system using response surface methodology. The values of R(2) 0.9716, 0.9699 and 0.9982 for Pb(II), Cd(II) and Cu(II) ions, respectively, indicated the validity of the model. The thermodynamic properties DeltaG degrees , DeltaH degrees , DeltaE degrees and DeltaS degrees by the metal ions for biosorption were analyzed using the equilibrium constant value obtained from experimental data at different temperatures. The results showed that biosorption of Pb(II) ions by T. viride adsorbent is more endothermic and spontaneous. The study was attempted to offer a better understating of representative biosorption isotherms and thermodynamics with special focuses on binding mechanism for biosorption using the FTIR spectroscopy.

Distribution and biodegradation of polycyclic aromatic hydrocarbons in contaminated sites of Hisar (India).

Fifty-two soil samples were collected from various location of the Hisar city. These samples were analysed for six polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, phenanthrene, anthracene, fluoranthene, and pyrene). Total mean concentration of six PAHs varied from 51.79 to 148.82 mg kg(-1) dry weight of the soil, PAH concentration was higher in soil samples from local auto market while lower concentration was recorded in agricultural soil. Effect ofpH (5.0 to 9.0), temperature (20 degrees to 40 degrees C), and concentration of PAHs (5 to 20 mg kg(-1)) on biodegradation were optimized. Biodegradation of phenanthrene (3-ring) and pyrene (4-ring) was evaluated using two acclimatized microbial strains Pseudomonas putida and Pseudomonas paucimobilis. Biodegradation was maximum in sterilized artificial spiked soil with phenanthrene (5 mg kg(-1)) and pyrene (5 mg kg(-1)) at pH 7.0 and at 30 degrees C (optimized conditions) than the native unsterilized contaminated soil (without optimized conditions) in 42 days of incubation period with Pseudomonas putida and Pseudomonas paucimobilis. Phenanthrene was completely disappeared after 28 days with P. putida and after 35 days with P. paucimobilis. Whereas, pyrene was disappeared up to 97.40% with P. putida and 95.5% with P. paucimobilis after 42 days incubation period at optimum conditions. Under unoptimized conditions, disappearance of phenanthrene was 65.89% with P. putida and 57.81% with P. paucimobilis after 42 days, whereas the % disappearance of pyrene was 59.80% with P. putida and 52.07% with P. paucimobilis.

Biosorption of Cr (VI) with Trichoderma viride immobilized fungal biomass and cell free Ca-alginate beads.

Ability of Cr (VI) biosorption with immobilized Trichoderma viride biomass and cell free Ca-alginate beads was studied in the present study. Biosorption efficiency in the powdered fungal biomass entrapped in polymeric matric of calcium alginate compared with cell free calcium alginate beads. Effect of pH, initial metal ion concentration, time and biomass dose on the Cr (VI) removal by immobilized and cell free Ca-alginate beads were also determined. Biosorption of Cr (VI) was pH dependent and the maximum adsorption was observed at pH 2.0. The adsorption equilibrium was reached in 90 min. The maximum adsorption capacity of 16.075 mgg(-1) was observed at dose 0.2 mg in 100 ml of Cr (VI) solution. The high value of kinetics rate constant Kad (3.73 x 10(-2)) with immobilized fungal biomass and (3.75 x 10(-2)) with cell free Ca- alginate beads showed that the sorption of Cr (VI) ions on immobilized biomass and cell free Ca-alginate beads followed pseudo first order kinetics. The experimental results were fitted satisfactory to the Langmuir and Freundlich isotherm models. The hydroxyl (-OH) and amino (-NH) functional groups were responsible in biosorption of Cr (VI) with fungal biomass spp. Trichoderma viride analysed using Fourier Transform Infrared (FTIR) Spectrometer.

Biosorption of Cr(III) from aqueous solution using algal biomass spirogyra spp.

In the present investigation, a fresh water green algae spirogyra spp. was used as an inexpensive and efficient biosorbent for Cr(III) removal from aqueous solution. The algal biomass was treated with 0.1M NaOH, 0.2M CaCl(2) and 5% HCHO. The biosorption efficiency was compared with untreated biomass. The effects of various physico-chemical parameters were studied, e.g. pH 3.0-6.0, initial metal ions concentration 20-150mgL(-1), algal dose 1.0-3.0gL(-1), and contact time 15-180min, respectively. Biosorption of Cr(III) is highly pH dependent. Maximum 81.02% adsorption of Cr(III) was observed with 0.2M CaCl(2) treated biomass at pH 5.0. Removal of Cr(III) was more than 70% in 45min of contact time with different treated and untreated algal biomass at concentration 30mgL(-1). Maximum metal uptake (Q(max)) was observed as 30.21mgg(-1) with 0.2M CaCl(2) treated algal biomass indicate good biosorbents than other treated and untreated biomass. The high values of correlation coefficient (r(2)<0.90) indicate equilibrium data of treated and untreated form of algal biomass well fitted in Freundlich than Langmuir isotherms model equations.