Development of stable mixed microbiota for high yield power to methane conversion

Background: The alterations caused by the addition of H2 and CO2 to a mixed, thermophilic biogas producing microbial community were studied with the goal of developing a stable, sustainable microbiota for optimum performance in the Power-to-Biomethane conversion. Methods: Various amounts of non-stoichiometric and stoichiometric mixtures of H2/CO2 were injected into the headspace of laboratory batch reactors containing effluent from an industrial thermophilic biogas facility. Fermentation, bioconversion parameters were recorded continuously for 71 days. The microbial community compositions at the beginning and end of the experiment were determined and analyzed by Illumina sequencing and a sophisticated bioinformatics workflow. Results: The rearrangement of the microbial community took place under gas fermentation conditions. This was reflected both in the fermentation parameters and direct determination of the composition of the microbial communities. Conclusions: Rational management of the microbial community and development of a mixed microbiota carrying out the desired bioconversion at high selectivity and yield is possible under thermophilic conditions.