秸秆纤维素降解真菌的筛选及产酶条件的优化

利用羧甲基纤维素钠水解圈法、滤纸崩解法、酶活测定法筛选能降解秸秆纤维素的真菌,并在秸秆产酶培养基上对不同秸秆长度、培养时间、氮源、氮源投加量和pH对产酶的影响进行了研究。结果表明,筛选出的两株菌株LK8和LK10降解能力较强,经鉴定LK8属于曲霉菌属(Aspergillus cf.flavipes ATUS),LK10属于青霉菌属(Penicillium sp.LH33);菌株LK8和LK10的最优产酶条件为:温度30℃,初始pH值6.0,4 cm秸秆段为碳源,硫酸铵为氮源,氮源投加量分别为LK8:1%,LK10:小麦0.5%、水稻1%;在1周之内酶活性变化较小,LK8和LK10的酶活性分别可达到26.19 U/mL和22.32 U/mL。

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.