Screening of straw cellulose-decomposing fungi strain and the optimization of enzyme-production conditions

In order to screen straw-cellulose degrading microorganisms and to investigate the qualification of producing enzymes,the methods including disintegration test of filter paper scrip,hydrolysis spot diameter measurement method of CMC-Na and measurement of extracellular enzyme activity were used.The effects of different length,time,nitrogen source,supply of nitrogen source,pH value on the enzyme activity were analyzed.The results showed that two fungi with cellulose degrading ability,i.e.LK8 and LK10 were isolated.They were identified as Aspergillus cf.flavipes ATUS and Penicillium sp.LH33,respectively.The best condition of producing enzymes for LK8 and LK10 were as follows: temperature of 30%,pH value of 6,length of 4 cm,(NH4)2SO4 of 1% and 0.5%.The change of enzymatic activity was insignificant in one week.The enzymatic activity of LK8 and LK10 reached 26.19 U/mL and 22.32 U/mL,respectively.