1株产嗜热酯酶菌株的分离、鉴定及酯酶部分酶学性质分析

Isolation and Enzymatic Properties of a Thermophilic and Thermostable Esterase-producing Strain

为从土壤环境中分离筛选产嗜热酯酶的菌株,利用三丁酸甘油酯筛选培养基,从沼气堆肥发酵周边的土壤中筛选到1株产酯酶的菌株YJ 1-1,根据其形态特征、生理生化特征及16S r DNA序列分析,初步确定为嗜麦寡养单胞菌(Stenotrophomonas maltophilia)。菌株YJ 1-1生产的酯酶在以对硝基苯酚丁酸酯为底物时,酶活性最高(2. 87 U/mg),其最适反应温度为75℃,最适反应pH为7. 0,且该酶表现出极强的温度稳定性和有机溶剂耐受性,75℃处理12 h,其酶活性没有明显的变化,70%(体积分数)的甲醇、二甲基甲酰胺、丙三醇、正丙醇、二甲基亚砜、乙醇、异丙醇和丙酮等有机溶剂对酯酶活性均有激活作用,分别使酯酶活性提高了2. 30、4. 65、2. 05、1. 30、5. 02、1. 74、1. 09和2. 12倍。上述特征使得该酯酶可应用于工业生产过程中。

In order to screen thermophilic esterase-producing strain, tributyrin agar plate is used to screen strain from composting fermentation soil collected from around compost fermentation of biogas station. One Stenotrophomonas maltophilia strain YJ 1-1 was identified by morphological characteristics and biochemical tests and 16S rDNA gene sequence analysis. The esterase reached the highest activity at 75 ℃ and pH at 7.0. And the enzyme showed good thermal stability and it did not show obvious loss of activity after incubation at 7 ℃ for 12 h. Methanol, dimethyl formamide, glycerol, propylene glycol, dimethyl sulfoxide, ethanol, isopropyl alcohol and acetone increased activity of the enzyme 2.30, 4.65, 2.05, 1.30, 5.02, 1.74, 1.09 and 2.12 times, respectively. The thermal stability and organic solvent tolerance of esterase could be applied for industrial production.