Isolation and enzymatic characteristics of the microorganisms in lignocellulose-degradation microbial community WSD-5

Abstract:

The microbial community WSD-5 could not only degrade wheat straw but also secret extracellular enzyme efficiently. In order to further study the synergistic decomposition mechanism of WSD-5 and optimize the microbial combination, 11 bacterial strains and 3 fungal strains were isolated from the microbial community WSD-5. The closest relatives of 11 bacterial strains were Pseudomonas sp., Pseudomonas aeruginosa, Achromobacter sp., Stenotrophomonas sp., Bacillus fusiformis, Bacillus cereus, Brevundimonas sp., Ochrobactrum sp., Cytophaga sp., Benzo(a)pyrene-degrading bacter, Flavobacterium sp. by sequencing nearly complete 16S rDNA and the closest relatives of 3 fungal strains were Pseudallescheria boydii, Coprinus cinereus by sequencing 26S rDNA. Whereas transparent circles were detected on carboxymethylcellulose (CMC) plates with 4 bacterial strains and 3 fungal strains, there were only 3 fungal strains which had the enzymatic productivity by determining the enzyme activity. The results of dynamic trend of enzyme activity showed that the peak heights occurred at 7?14 days. The F1 expressed the highest filter paper activity (1.05 U/mL), the highest cellulose endonuclease activity (5.53 U/mL) and the highest exonuclease activity (0.56 U/mL). The highest β-glucosidase activity (0.44 U/mL) and xylanase activity (58.95 U/mL) were expressed by the FC. The highest xylanse activity of FC was 6 times higher than that of F1.