Biofilm-forming microbiota of a full-scale biogas reactor

Biogas is a flexible carrier of renewable energy, since methane can partly substitute fossil fuels for both heat and power generation and as fuel. Anaerobic digestion of biowastes in a full-scale biogas reactor was improved by the addition of straw, while the organic loading rate (OLR) could be increased in order to gain higher methane production. The composition of microbial community on straw as biofilm carrier and in fluid reactor content was analyzed by a 16S rDNA 454 pyrosequencing. The microorganisms Candidatus Cloacomonas acidaminovorans and the methanogenic archaeum Methanoculleus dominated the biofilm on straw. Most likely a syntrophic interaction between C. acidaminovorans and the hydrogenotrophic Methanoculleus is responsible for the achievable higher biogas yield after straw addition.