产纤维素酶菌株的筛选与鉴定及发酵条件优化研究

Study on Screening,Identification of Producing Cellulase Strains and Its Optimization of Fermentation Conditions

从枯树叶及其覆盖的土壤中筛选分离分解纤维素的菌株并进行16S rRNA鉴定,优化其发酵条件。采用CMC-刚果红染色法初筛分解纤维素的菌株,用显微镜观察其形态结构,用16S rRNA序列分析其系统分类地位。单因素试验确定氮源、碳源、pH值和温度对发酵液中羧甲基纤维素酶(CMC)、滤纸酶(FPA)活力的影响。结果表明,分离到1株高效分解纤维素的菌株SKX-1,鉴定SKX-1为蜡样芽胞杆菌(Bacillus cereus);最优发酵条件为以蛋白胨为氮源、羧甲基纤维素钠(CMC-Na)为碳源,温度37℃,pH值为7,发酵培养后,CMC酶活力达到173.3 U/mL,FPA酶活力达到210.5 U/mL。该试验为菌株Bacillus cereus SKX-1的利用提供了理论基础。

Bacterial strains of decomposing cellulose were screened from dead leaves and their covered soil and identified by 16S rRNA.Thefermentation conditions were optimized.CMC-Congo red staining was used to screen decomposing cellulose strains,and its morphological structure waobserved by microscope.Its systematic classification status was analyzed by 16S rRNA sequence.The effect of nitrogen,carbon,pH and temperature onthe activity of CMC and FPA in fermentation broth were determined by single-factor test.The results showed that a strain of high-efficiency cellulosedecomposing（SKX-1） was isolated and identified as Bacillus cereus .The optimal fermentation condition for SKX-1 was taken peptone as nitrogensource,and CMC-Na as carbon source,the activity of CMC and FPA were 173.3 U/mL and 210.5 U/mL under the fermentation conditions of 37C,pH=7This experiment could provide a theoretical basis for the application of Bacillus cereus SKX-1.