Enrichment and optimization of anaerobic bacterial mixed culture for conversion of syngas to ethanol

• Published in: Bioresource technology 2014-11, Vol.172, p.41-49
• Main Authors: Singla, Ashish, Verma, Dipti, Lal, Banwari, Sarma, Priyangshu M.
• Format: Article
• Language: English
• Subjects: Acetic acid; Acetic Acid - metabolism; Anaerobiosis; Bacteria; Bacteria - growth & development; Bacteria - metabolism; Biological and medical sciences; Biomass; Biotechnology; Biotechnology - methods; Cell Culture Techniques; Conversion; Culture; Enrichment; Ethanol; Ethanol - metabolism; Ethyl alcohol; Fermentation; Fundamental and applied biological sciences. Psychology; Gases - metabolism; Hydrogen-Ion Concentration; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Mixed culture; Optimization; Pressure; Syngas; Temperature; Up-scaling
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2014.08.083

•Anaerobic bacterial mixed culture enriched for conversion of syngas to ethanol.•Operational parameters optimized for enhancing ethanol production from syngas.•Semi-continuous fermentation study done for getting increased ethanol production.•Up-scaling studies done for further enhancing ethanol production from syngas. The main aim of the present study was to enrich anaerobic mixed bacterial culture capable of producing ethanol from synthesis gas fermentation. Screening of thirteen anaerobic strains together with enrichment protocol helped to develop an efficient mixed culture capable of utilizing syngas for ethanol production. Physiological and operational parameters were optimized for enhanced ethanol production. The optimized value of operational parameters i.e. initial media pH, incubation temperature, initial syngas pressure, and agitation speed were 6.0±0.1, 37°C, 2kgcm−2 and 100rpm respectively. Under these conditions ethanol and acetic acid production by the selected mixed culture were 1.54gL−1 and 0.8gL−1 respectively. Furthermore, up-scaling studies in semi-continuous fermentation mode further enhanced ethanol and acetic acid production up to 2.2gL−1 and 0.9gL−1 respectively. Mixed culture TERI SA1 was efficient for ethanol production by syngas fermentation.