Abstract:

【Objective】 In order to investigate the degradation activity, optimal condition of secreted cellulase activity and compose, the microbial community with efficient cellulose degrading ability in 28℃ was studied. 【Method】 Microbial community came from rotted rice straw was enriched and directional domesticated by improved Mandels medium. The standard cellulase activity assays were used to determine cellulase activity, the fermented juice was analyzed by gas chromatography mass spectrometry (GC/MS) method, and denaturing gradient gel electrophoresis (DGGE) was used to identify the composition dynamic of the community. 【Result】 The results showed that the microbial community could degrade 39.6% of rice straw gross weight within five days. When the culture medium volume was 1/5 of the whole and pH at 6 on the 5 days culture, the CMC reached the highest of 14 IU?ml-1. During the rice straw degradation, more than ten kinds of products were detected using GCMS. DGGE detected the dynamic change of microbial community composition, and the microbial composition changed greatly in different periods. The phylogenetic tree derived from 16s rDNA sequence was found that the closest relatives belong to Clostridium sp., Brevibacillus sp., Bartonella sp.、Bacteroidetes sp. 【Conclusion】 This microbial community could accelerate rice straw rotting.

Key words: normal temperature, microbial community, lignocellulose degradation, lignocellulase, microorganism diversity