Plant biomass is the most abundant biopolymer on earth and a potential source of mixed sugars for bioenergy production.  Our goals are to understand diversity and metabolic capabilities of microbial communities for converting plant biomass into biofuels-producing feedstock.  Using metagenomics approach allows the discovery of new enzymes from microbial communities, especially from unknown or never-been-cultivated organisms.  From an anaerobic microbial community actively decaying poplar biomass, metagenomic DNA was isolated and sequenced using 454-GS-FLX Titanium pyrosequencing.  Approximately 720Mbp reads were generated which assembled into 128 Mb contigs.  A total of 198,375 DNA contigs contain 653,488 putative genes.  16S/18S rRNA libraries and 454-pyrotag sequencing, dinucleotide frequency analysis with Aglomerative clustering (AGNES), and ensemble's G/C content analysis all suggest the community is dominated by 5 demarcated phylogentic groups.  Links between phylogentic groups and functions (COG/Pfam assignments) are currently under investigation.  Approximately 4,000 glycosyl hydrolase homologues were identified using blastx searches against CAZy database.  Based on homology to GHase families/activities of interest (key enzymes for efficient decay of plant cell wall recalcitrants) and quality of sequences, candidates were selected for further investigation.  Full-length open reading frames were obtained using inverse PCR and DNA walking, and subsequently cloned into an expression vector for expressing in E. coli.  Protein purification and characterization are presently in process.  Construction of the metagenome expression library and enzyme activity screening are also in progress.  Our studies have shown that microbial community metagenomic could be a resource for mining new biomass deconstructive enzymes and screening cellulolytic activities.