产菊粉酶微生物的筛选及发酵工艺的研究

Separation of Inulinase-producing Strain and Optimization of its Fermentation Conditions

以菊粉为唯一碳源,从菊芋切面及表皮的土壤中筛选出产菊粉酶的微生物,其中霉菌5株,放线菌19株,酵母4株,细菌3株,经复筛菌株M08的发酵液酶活最高。其摇瓶发酵的最优条件为(g/L):75%的菊粉20,酵母膏15,NaCl5,NH4H2PO40.5,ZnSO4·7H2O0.5,FeSO4·7H2O0.1,pH7,接种2.5×106cfu/mL的孢子悬浮液0.5mL,250mL的三角瓶中装30mL的发酵培养基,29℃,90r/min下培养5d酶活力可稳定在3.28U/mL,比酶活25.43U/mg。

19 mildews strain, 5 actinomyces strains, 4 yeast strains and 3 bacteria strains with inulinase-produeing capbility were screened and isolated on the media using inulin as the only carbon source. Among the screened strains, M08 had the highest inulinase activity. The optimum fermentation conditions were： 20 g/L of 75% inulin, 15 g/L of yeast extract, 5 g/L of NaCl, 0.5 g/L of NH4H2PO4, 0.5 g/L of ZnSO4＂7H20, 0.1 g/L of FeSOa-7H2O, fermentation pH 7, temperature 29 ℃, 0.5mL of spore suspensions （2.5 × 106 cfu/mL）, shaking speed 90 r/min, 30 mL medium flask （250 mL） and fermentation time of 5 days. Under these conditions, the maximum enzyme activity was 3.28 U/mL and the specific activity was 25.43U/mg.