产果胶酶菌株的筛选鉴定及其产酶条件的研究

为筛选果胶高效降解菌株,结合HC比值(透明圈H与菌落直径C的比值)和果胶酶活力测定,从桔子园土壤和腐烂的水果等处筛选得到1株产果胶酶活力较强的菌株M3,结合菌株形态特征观察和ITS rDNA基因序列分析,确定该菌株为聚多曲霉(Aspergillus sydowii).经发酵产酶试验可知,该菌株的最适发酵产酶条件为培养温度30℃,初始pH4.5,接种量(体积分数)7%,培养时间4 d.在该条件下发酵,果胶酶活力可达42.01 U.mL-1.

Screening and identification of pectinase-producing strains and studying on the enzyme-producing conditions

HC values(ratio of diameters of clearing zone to colony on the pectin-Congo red agar plate) and pectinase activity were assayed to screen strains for efficient pectinase production.One strain,named M3,was isolated from samples rich in pectin.The strain was identified as Aspergillus sydowii via morphological observation and its ITS rDNA sequence analysis.Furthermore,the conditions for pectinase production were explored and the optimum conditions were achieved: temperature 30 ℃,initial pH4.5,inoculum volume 7%(v/v),fermentation period 4 d.Under these conditions,the maximum pectinase activity was 42.01 U·mL-1.