Screening and construction of a novel microbial consortium SSA-6 enriched from the gut symbionts of wood-feeding termite, Coptotermes formosanus and its biomass-based biorefineries

摘要

Biorefinery industry from lignocellulose faces one major obstacle which lies in the inefficient degradation of biomass. Lignocellulosic processes in wood-feeding termites are considered to be a very efficient biodegradation reaction due to a significant contribution from gut symbionts. In the present study, high degradation ratio of sawdust (84.3%) was achieved by the stable microbial consortium Cf-S, enriched from the termite gut symbionts of Coptotermes formosanus, within 120 h at 35 degrees C and pH 7. Molecular identification and phylogenetic analysis of Cf-S indicated that two yeasts and four bacterial candidates were identified for new species. Clustering and ordination analyses of Cf-S revealed that six strains Cf-S-2, Cf-S-6, Cf-S-11, Cf-S-20, Cf-S-22 and Cf-S-17 exhibited metabolic activities and physiological capabilities compared with other strains. These six strains were selected to construct a novel microbial consortium, designated SSA-6 that could make SSA-6 potentially consortium suitable for a wide variety of applications. The synergistic interaction of SSA-6 candidates led to significant higher cellulolytic, xylanolytic and ligninolytic activities than that produced by either strain alone (P=0.003, 0.003 and 0.004, respectively). The consortium SSA-6 showed significant lower time for dye removal (Remazol Brilliant Blue R, Azure B, and Methylene Blue) together with higher dye concentration and decolorization ratio when compared with each individual strain (P 0.001). The co-culture SSA-6 candidates produced 84.3, 203.6 and 168.4% more ethanol than that produced by Cf-S-2, Cf-S-17 and Cf-S-22 alone, respectively. This study shows the potential of constructing a novel microbial consortium valued for biomass-based biorefineries.