Abstract: High-efficiency straw-degrading bacteria were screened by straw powder plate,Congo red staining method and degradation rate of wheat straw. The extracellular cellulase activities of the strains were determined to study the degradation ability of the straw cellulose. The results showed that among the 4 strains of fungi screened,the strain z-5 had the highest degradation rate of 47%,and that of strain 4-1,3-1 and 2-2 were 45%,32% and 31%,respectively. The filter paper-decomposing test results were similar to the straw degradation test results. Four strains all had exo-1,4-β-D-glucanase,endo-1,4-β-D-glucanase,and β-glucosidase,but their degradation trends were different. The three enzyme activities of strain z-5 and strain 4-1 showed better synergy,and that of strain 2-2 and strain 3-1 were less synergistic. In sum,the target strain can be obtained more accurately and quickly through the straw powder plate test,straw degradation rate determination and filter paper hole method,and the cellulase plays a leading role in straw degradation.

Key words: straw-degrading bacteria, strain screening, cellulase, filter paper degradation