Enrichment and microbial characterization of syngas converting anaerobic cultures

Abstract

Bioconversion of recalcitrant biomass/waste into bulk chemicals or biofuels is often not feasible. By gasification of these materials, syngas (mainly composed of CO2, CO and H2) is generated and can be used for the production of high value compounds by thermochemical or biotechnological processes. Here, three thermophilic cultures enriched with syngas mixtures or pure CO (T-Syn, T-Syn-CO and T-CO) were studied. Stable enriched cultures obtained by subsequent transfers for over a year, convert syngas/CO to mainly acetate and hydrogen (CO partial pressure up to 0.88 bar). 16S rRNA based techniques (PCR-DGGE) showed that predominant microorganisms in the cultures belonged to Desulfotomaculum, Caloribacterium, Thermincola and Thermoanaerobacter genera. Moreover, from the syngas- and CO-degrading cultures, a novel Thermoanaerobacter sp. (strain PCO) and a novel Moorella sp. (strain E3-O) were isolated.