产β-甘露聚糖酶菌株的筛选及其产酶条件优化

Screening of Bacterial Strain for Producingβ-mannanase and Optimization of Enzyme-producing Conditions

从土壤中分离筛选出5株产胞外β-甘露聚糖酶的菌株,其中XB2菌株摇瓶培养液的粗酶活力达4.81 U/mL。通过单因素实验和正交优化实验,确定了其最佳发酵产酶条件。菌株产酶最适培养基组成为:魔芋精粉1.5 g、NaNO3 0.3 g、MgSO4 0.3 g、KCl 0.5 g、K2 HPO4 0.1 g、FeSO4 0.001 g,加水至100 mL。产酶最适培养条件:培养温度37℃,培养基起始pH 6,接种量3%,转速160 r/min,摇瓶培养72 h。此条件下酶活力高达9.12 U/mL。

Five bacterial strains of producing extracellularβ-mannanase were isolated and screened from the soil.The enzyme activity of strain XB2 in shaking culture medium reached 4.81 U/mL.Single factor experiment and orthogonal optimization experiment determined the optimal fermentation conditions for enzyme production as follow;the optimal composition of the medium（konjac powder 1.5 g,NaNO3 0.3 g,MgSO4 0.3 g,KCl 0.5 g,K2 HPO4 0.1 g and FeSO4 0.001 g）,adding H2O to 100 mL,at 37℃,the initial medium pH 6,inoculation amount 3%,rotating speed 160 r/min and shaking culture for 72 h. Under these conditions the enzyme activity reached 9.12 U/mL.