Hydrogen-Sulfide-Free Methane Production by Fermenter–Methanogen Syntrophy Using Dacite Pumice under Aerobic Gas Phase

Abstract

Biological CH4 is produced by the process of syntrophy between fermenters and methanogens. CH4 from biological waste products is produced by complex syntrophic systems, which additionally include aerobes and facultative anaerobes jointly working to convert various organics to substrates for the fermenters. However, as a result of complexity of the constituents, these systems are prone to environmental changes, such as those in the O2 concentration and pH. Furthermore, H2S from sulfur-containing organics is corrosive to metals in the equipment. Here, we studied the principles of biological CH4 production through establishment of a system where combustible H2S-free CH4 can be produced daily. Toward this objective, we applied a solid-phase cultivation method, using dacite pumice, to a simple syntrophic system of Thermosipho globiformans and Methanocaldococcus jannaschii. Dacite pumice, used as a solid support for anaerobic co-cultivation of these microorganisms, was the inoculum for solid-phase carried-over ...