Establishment and Analysis of Microbial Communities Capable of Producing Methane from Grass Waste at Extremely High C/N Ratio

S. Matsuda, T. Ohtsuki

Acclimation of microbial communities, aiming to methane production from grass as a sole substrate at extremely high carbon-to-nitrogen (C/N) ratio, was conducted.  In a series of experiments with various sizes of added grass, two microbial communities showing high methane production were obtained with powdered grass.  In the two microbial communities designated NR and RP, Bacteroidia including genera Bacteroides, Dysgonomonas, Proteiniphilum, and Alistipes were detected as dominant members in eubacteria.  It was also shown that Methanomicrobia and Methanobacteria including genera Methanomassiliicoccus and Methanobacterium were found as dominant members in methanogen.  It is noteworthy that nitrogen fixation were observed both in NR and RP, suggesting that insufficiency of nitrogen sources would be complemented by uptake of nitrogen from gaseous phase in culture.