产菊粉酶菌株的筛选及其产酶条件的优化

Isolation of inulinase production strain and optimization of its fermentation condition

从山东滨海盐碱地种植菊芋的根际土壤中分离得到能产菊粉酶的菌株46株,经过进一步的摇瓶复筛,获得了产菊粉酶能力较高的1株菌株,经初步鉴定为青霉Penicilliumsp.B01。在对其发酵条件优化后,确立了Penicilliumsp.B01最适宜的产酶条件为(g.L-1):菊芋提取液(EJA)120、酵母膏(YE)25、NH4H2PO42.5、NaCl 5.0、FeSO4.7H2O0.1、ZnSO4.7H2O 0.1,初始pH7,接种2.5×106mL-1的孢子悬浮液3.75%,250 mL的三角瓶中装40 mL的发酵培养基,在30℃、170 r.min-1下发酵3 d后菊粉酶活性最高可达25.78 U.mL-1。此酶主要为外切酶。

46 strains capable of producing inulinase were isolated from rhizosphere soil of Jerusalem artichoke （ Helianthus tuberosus L. ） in the salt-affected lands of Laizhou, Shandong Province. Of all, a strain with high inulinase productivity was obtained through further screening. This strain was identified as Penicillium sp. B01 primarily. After studying on its fermentation condition, the optimum condition for higher inulinase production by Penicillium sp. B01 was determined as shown below （g·L^-1 ） ： extract of Jerusalem artichoke 120, yeast extract 25, NH4H2PO4 2.5, NaCl 5.0, FeSO4·7H20 0. 1, ZnSO4 · 7H20 0. 1 ; pH 7, inoculated with 3.75% of spore suspensions （2. 5 × 10^6 mL^-1 ）. Maximal inulinase activity of Penicillium sp. B01 was 25.78 U ~ mL^-1 and obtained after 72 h of growth in shake cultures （40 mL of medium in 250 mL flasks）. This inulinase was mostly exo-inulinase.