A Community Approach to Identifying New Cellulases

Cellulases for the hydrolysis of plant biomass have traditionally been identified and characterized from fungal and bacterial isolates.  In natural environments, microbial consortia are responsible for lignocellulose deconstruction. However, these native communities, found in rumen or compost as examples, are often too complex to assign functions to individual enzymes. In this talk, I will describe an approach to cellulase discovery by adapting communities from compost to grow with biomass substrates as the sole carbon source. Maintaining temperature and pH, simple and predictable community structures were obtained and the role of individual cellulases in these communities elucidated by a combination of meta-omics methods and biochemical techniques. I will focus on the characterization of a non-cellulosomal hydrolytic complex isolated from an uncultivated thermophilic Firmicutes species and the unexpected role of an actinobacterial glycoside hydrolase family 12 protein in the hydrolysis of crystalline cellulose.