Department of Chemical Engineering

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Author: search.filters.author.Mishra, Somesh

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    Carbon dioxide to bio-fuels by mixed and pure microbial cultures isolated from activated sludge: relative evaluation of CO2 fixation, biodiesel production, and thermodynamic analysis
    (Wiley, 2019-08-31) Gupta, Suresh; Raghuvanshi, Smita; Mishra, Somesh
    In the present work, the CO2(g) bio-mitigation potential (15% [v/v]) of a mixed microbial population, Enterobacter cloacae and Pseudomonas putida, is thermodynamically assessed and compared at different Fe(II) concentrations (energy source). CO2(g) removal efficiency values are evaluated on per-day basis for all cultures and found maximum for the mixed microbial population. Approximate material balance and thermodynamic assessment of the CO2(g) bio-mitigation studies have revealed that among all cultures, the mixed microbial population shows the highest actual CO2 utilization efficiency (R.RCO2) of 57.67 (±0.04)%. Leachate (biomass + cell free supernatant) obtained from CO2 bio-mitigation batch studies were analyzed using FTIR and gas chromatography–mass spectroscopy. The results obtained have shown the presence of fatty acids and hydrocarbons in considerable amounts. The fatty acids obtained from cultures have shown the presence of a carbon chain length in the range of C7–C25, which makes it a potential source of biodiesel. Biodiesel yields of 91.55%, 77.49%, and 38.69% were obtained for the mixed microbial population, E. cloacae and P. putida. The hydrocarbons obtained from all the microbial cultures were found to have a carbon chain length in the range of C9–C32 and comprised saturated and unsaturated groups, which make them comparable to light oil.
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    Investigation on CO2 bio-mitigation using Halomonas stevensii in laboratory scale bioreactor: Design of downstream process and its economic feasibility analysis
    (Elsiever, 2018-03) Gupta, Suresh; Raghuvanshi, Smita; Mishra, Somesh
    In the present study, H. stevensii was cultivated on a semi-continuous mode in a laboratory scale bio-reactor using CO2(g) [15% (v/v)] as carbon source and thiosulfate (S2O32−) as an energy source for the total duration of three days. Approximately, 100% CO2(g) removal from gaseous phase was achieved. Leachate obtained was subjected to different downstream bio-processing strategies. Biomass harvesting using filtration and recovery of metabolites without cell disruption using solvent extraction from wet biomass was observed as the best downstream processing strategy. Qualitative analysis of products was carried out using gas chromatography and mass spectroscopy (GC–MS) and their results have indicated fatty alcohols (C8–C27) as primary metabolites. Fourier transform infrared spectroscopy (FTIR) analysis, approximate material balance and thermodynamic analysis have confirmed the intracellular assimilation of CO2(g) as HCO3− and its metabolization into fatty alcohols. Economic feasibility of the process has suggested that the developed downstream process has the capability to replace coconut oil based process for the production of fatty alcohols (C12–C14) and it can be utilized for the production of dodecanol as compared to the tetradecanol.
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    Application of novel thermo-tolerant haloalkalophilic bacterium Halomonas stevensii for bio mitigation of gaseous phase CO2: Energy assessment and product evaluation studies
    (Elsiever, 2017-04) Gupta, Suresh; Raghuvanshi, Smita; Mishra, Somesh
    Present work deals with the bio-mitigation potential of gaseous phase CO2 by chemolithotrophic bacterium Halomonas stevensii isolated from haloalkaliphilic habitat using thiosulfate ion (S2O32−) as an energy source. H. stevensii was tested for various abiotic stress tolerances such as salt [2–12% (w/v)], temperature (10–60 °C) and pH (2–12). Batch studies were conducted for 6 days at 15 (±1) % (v/v) inlet CO2 concentration to find the CO2 fixing capability of H. stevensii under varying concentration of energy substrate i.e. 0, 50 and 100 mM Na2S2O3. Approximately 98% CO2 removal from gaseous phase was achieved at 50 and 100 mM Na2S2O3. Evaluation of CO2 fixation by H. stevensii and carbon allocation into different cellular organic pool (carbohydrate, proteins and primary metabolite) was carried out by growing H. stevensii at 5%, 10% and 15% (v/v) inlet CO2 concentration for the duration of 6 days. The obtained leachate was quantified using chemical technique, FT-IR and GC. Utilization of gaseous phase CO2 by H. stevensii was also proven by conducting the approximate materials balance and energy assessment for the present CO2 fixation process. The mechanism of CO2 metabolism by H. stevensii was evaluated using GC–MS and carbon partitioning into cellular organic pool analysis.
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    Energetic assessment of fixation of CO2 and subsequent biofuel production using B. cereus SM1 isolated from sewage treatment plant
    (Springer, 2016-04-13) Gupta, Suresh; Raghuvanshi, Smita; Mishra, Somesh
    The ongoing work on global warming resulting from green house gases (GHGs) has led to explore the possibility of bacterial strains which can fix carbon dioxide (CO2) and can generate value-added products. The present work is an effort in this direction and has carried out an exhaustive batch experiments for the fixation of CO2 using B. Cereus SM1 isolated from sewage treatment plant (STP). The work has incorporated 5-day batch run for gaseous phase inlet CO2 concentration of 13 ± 1 % (%v/v). 84.6 (±5.76) % of CO2 removal was obtained in the gaseous phase at mentioned CO2 concentration (%v/v). Energetic requirement for CO2 fixation was assessed by varying Fe[II] ion concentration (0–200 ppm) on the per-day basis. The cell lysate obtained from CO2 fixation studies (Fe[II] ion = 100 ppm) was analyzed using Fourier transformation infrared spectroscopy (FTIR) and gas chromatography-mass spectroscopy (GC–MS). This analysis confirmed the presence of fatty acids and hydrocarbon as valuable products. The hydrocarbons were found in the range of C11–C22 which is equivalent to light oil. The obtained fatty acids were found in the range of C11–C19. The possibility of fatty acid conversion to biodiesel was explored by carrying out the transesterification reaction. The yield of biodiesel was obtained as 86.5 (±0.048) % under the transesterification reaction conditions. Results of this research work can provide the valuable information in the implementation of biomitigation of CO2 at real scenario.