Microbial degradation of lignocellulosic biomass: discovery of novel natural lignocellulolytic bacteria

Lignocellulosic biomass is the most abundant biomaterial on Earth and holds enormous potential as a source of fermentable sugars for cost-effective biofuel production. The main obstacle is the intractable and convoluted structure and composition of lignocellulosics which are mainly made of lignin, cellulose and hemicellulose. However, nature has equipped microbes with enzymes that can deconstruct lignocellulose and release fermentable sugars. In this study, we selected bacteria (belonging to 6 different genera) from nature that had been grown in minimal culture media with cellulose or lignin as the sole carbon source, and assessed their lignocellulolytic activities in qualitative and quantitative assays. Through sequence analysis of the 16S rRNA gene, we discovered a novel lignocellulolytic bacterial species, Chryseobacterium gleum, capable of degrading both cellulose and lignin. In addition, a few other bacterial species previously known to degrade either cellulose or lignin were found to have lignocellulolytic activities. The majority of these bacterial species were found to produce extracellular lignocellulolytic enzymes. Lignocellulolytic bacteria identified in this study may serve as sources of genes/enzymes which might find applications in biofuel production and other industrial applications.