Identification of bacteria involved in the decomposition of lignocellulosic biomass treated with cow rumen fluid by metagenomic analysis

Previously, pretreatment of plant biomass using rumen fluid systems was developed to decompose cell wall. However, microbes which involved in plant cell wall decomposition in this system have not been identified, because the conditions of this system are different from the in situ rumen environment. We investigated the bacteria involved in the decomposition of cellulose and hemicellulose in a waste paper with the rumen pretreatment system using shotgun metagenomic analysis with next generation sequencing. After pretreatment of waste paper, about a half of the cellulose and hemicellulose content was decomposed. Genes encoding for cellulase and hemicellulase were mainly found to belonging to Ruminococcus, Clostridium, and Exiguobacterium. This study shows that Clostridium and Exiguobacterium, which have not been identified as predominant genus involved in cellulose and hemicellulose decomposition, might be categorized as the main fibrolytic bacteria in this system.