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

摘要： 为发掘优良纤维素降解菌株，筛选羊粪堆肥发酵菌剂菌种资源，本研究以滤纸条为唯一碳源，从新鲜羊粪中分离出26株具有纤维素降解能力的菌株。通过测定其纤维素酶活力与秸秆降解率，筛选出7株优良纤维素降解菌株，并对7株菌进行16S rDNA序列比对，确定其分类学地位。利用线性拟合和多元回归解析菌株产酶活力与秸秆降解率之间的关系。结果表明，7株菌的全酶活性为1.03~2.83 U·mL^-1、外切酶为3.42~5.78 U·mL^-1、内切酶为1.24~3.25 U·mL^-1和β-葡萄糖苷酶为1.09~2.259 U·mL^-1。经鉴定分别为山原申氏菌(Shinella yambaruensis)、鸡眼草申氏菌(Shinella kummerowiae)、土地鞘氨醇盒菌(Sphingopyxis terrae subsp)、植物内生成对杆菌(Dyadobacter endophyticus)、潮湿纤维单胞菌(Cellulomonas uda)、水原假黄单胞菌(Pseudoxanthomonas suwonensis)等。测定菌株秸秆降解率发现均在15%以上，最高为菌株En1-1，达到28.53%。相关性分析表明，菌株产酶能力与秸秆降解能力呈现显著正相关，内切葡聚糖酶和外切葡聚糖酶是降解秸秆的关键因子。本研究筛选的菌株均具有较高的纤维素降解能力，可为羊粪堆肥发酵菌剂的制作储备优良菌株资源。

关键词: 羊粪, 纤维素降解菌, 酶活性, 降解率