蜡状芽孢杆菌Bacillus cereus SWWL6产耐有机溶剂脂肪酶发酵条件优化及酶学性质

Optimum Fermentation Conditions and Enzymatic Properties of Organic Solvent Tolerant Lipase from Bacillus cereus SWWL6

以蜡状芽孢杆菌Bacillus cereus SWWL6为产耐有机溶剂脂肪酶的出发菌株,对发酵产酶条件进行优化并研究其酶学性质。通过四因素三水平L9(34)正交试验,确定产酶的最优发酵条件为:pH6.5、温度35℃、每250mL容量瓶中装液量55mL、接种量4%,此条件下酶活力达45.62U/mL。该酶最适pH值范围为7.0～8.0,碱性条件下稳定。最适温度为40℃,超过40℃,酶活力急剧下降。K+、Na+、Mg2+、Ba2+对该酶活性有激活作用,Al3+、Cu2+、Zn2+、Ca2+对该酶活性有一定的抑制作用,Fe2+对该酶活性的作用效果不明显。SDS、EDTA均对该酶活性有抑制作用,其中尤以SDS的抑制作用最强。该酶对所试有机溶剂甲醇、环乙烷、异丙醇、乙醇、甲苯、丙酮、异戊醇均有一定的耐受性。

In order to maximize lipase production,culture conditions for Bacillus cereus SWWL6 having the ability to produce organic solvent tolerant lipase were optimized by L9（34） orthogonal array design.The optimal fermentation conditions were 55 mL of medium at pH 6.5 in 250 mL Erlenmeyer flask with 4% inoculum under orbital shaking of 150 r/min for 36 h at 35 ℃.The optimal pH for SWWL6 lipase ranged from 7.0 to 8.0.The enzyme was stable under alkaline conditions.The optimal temperature for SWWL6 lipase was 40 ℃,and its activity sharply declined at higher temperatures.The lipase activity was activated in the presence of K＋,Na＋,Mg2＋ and Ba2＋,and inhibited in the presence of Al3＋,Cu2＋,Zn2＋,Ca2＋,EDTA and SDS.Meanwhile,SDS was the strongest inhibitor.