关键词: 羊粪, 纤维素降解菌, 酶活性, 降解率

Abstract: In order to explore the excellent cellulose degrading strains of bacteria,the strain resources of sheep manure composting fermentation agent were screened. Using filter paper strips as the sole carbon source,26 strains with cellulose degrading ability were isolated from fresh sheep manure. Seven superior cellulose-degrading strains were selected out by measuring cellulase activity and straw degradation rate,and their taxonomic status was determined by 16S rDNA sequence alignment. The relationship between the enzymatic activity of the strains and the straw degradation rate was analysed using linear fitting and multiple regression. The results showed that the total enzyme activities of the seven strains ranged from 1.03 to 2.83 U·mL^-1,the exonucleases from 3.42 to 5.78 U·mL^-1,the endonucleases from 1.24 to 3.25 U·mL^-1 and the β-glucosidases from 1.09 to 2.259 U·mL^-1. The strains were identified as Shinella yambaruensis,Shinella kummerowiae,Sphingopyxis terrae subsp,Dyadobacter endophyticus,Cellulomonas uda and Pseudoxanthomonas suwonensis. The straw degradation rates of the 7 strains were all found to be above 15%,with the highest being strain En1-1 at 28.53%. Correlation analysis showed that the enzyme production capacity of the strains was positively significantly correlated with its straw degradation capacity,and that endoglucanase and exoglucanase were the key factors for straw degradation. The strains screened in this study all had high cellulose degrading capacity,which can be used as a good resource for the producing fermenting agents for sheep manure compost.

Key words: Sheep manure, Cellulose degrading bacteria, Enzyme activity, Degradation rate