高产果胶酶菌株的筛选鉴定及其发酵条件研究

Screening and Identification of a High-yield Pectinase Producing Strain and Studying on Its Fermentation Conditions

采用观察透明圈与液态发酵测酶活相结合的方法,从腐烂的水果中筛选获得1株果胶酶产生菌G1。通过形态观察与18S rDNA序列分析,鉴定菌株G1为黑曲霉。对G1菌株的发酵工艺进行优化,确定最佳培养基配方(g/L):桔皮粉32,麸皮10,(NH4)2SO422,Na2HPO4·12H2O 8.4,KH2PO41.4,MgSO4·7H2O 1.0,CaCl20.1,FeSO4·7H2O 0.1,ZnSO4·7H2O 0.1,培养基初始pH 6.5;最佳发酵条件是:装液量50 mL/250 mL,转速180 r/min,接种量9%(体积分数),32℃培养7 d。在此条件下,果胶酶活力达到270.4 U/mL,比优化前提高了8.7倍。

A pectinase-producing strain G1 was isolated from rotten fruit by the methods of transparent circle observation and pectinase activity determination. Strain G1 was identified as Aspergillus niger based on its morphological observation and analysis of 18S rDNA sequence. Through single-factor experiments, the optimum medium contains（g/L）： orange peel 32, bran 10,（NH4）2 SO4 22, Na2 HPO4 ·12H2 O 8.4, KH2 PO4 1.4, MgSO4 ·7H2 O 1.0, Ca2 Cl 0.1, FeSO4 ·7H2 O 0.1, ZnSO4 ·7H2 O 0.1, initial pH 6.5. The conditions for optimum pectinase-producing were the combination of the inoculums size 9%, medium volume 50 mL/250 mL, temperature 32 ℃, and shaking at 180 r/min for 7 days. Under these conditions, the pectinase activity which reached up to 270.4 U/mL was improved by 8.7 times compared with original pectinase activity.