腈水解酶产生菌游离细胞催化特性的初步研究  

Primary study on catalytic properties of free cells from nitrilase producing microorganism

作　　者：罗积杏[1] 薛建萍[1] 沈寅初[1] 

机构地区：[1]上海市农药研究所生物工程研究中心,上海200032

出　　处：《工业微生物》2006年第4期13-17,共5页Industrial Microbiology

摘　　要：从自然源筛选到的一株腈水解酶产生菌乳酪短杆菌（Brevibacterium casei），能够高选择性地将腈转化为羧酸，初步研究了该菌株所产的腈水解酶在游离细胞形态下的催化特性，包括热稳定性、pH稳定性、金属离子和添加剂的作用、溶剂耐受性及底物特异性等。结果表明：酶在45℃和pH6．8条件下表现出最高催化活性，在20℃和pH6．5～8．5下酶活稳定，Mg^2＋和Mn^2＋对酶活性有轻微的促进作用，但Fe^3＋、Cu^2＋、Al^3＋和Sn^2＋强烈抑制酶，表面净陛剂OP、NP10及RS010有促进酶活作用，十二烷基磺酸钠却产生较强抑制作用，L-半胱氨酸能够减弱重金属离子对酶的抑制。该酶对芳香族腈、脂肪族腈、饱和腈与不饱和腈均能作用，并具有较好的对映体选择性。有机溶剂会使酶失活，但酶对甲醇具有一定的耐受性，在6％（V／V）浓度下，20h后酶的残留活性为98．8％。A new strain of Brevibacterium casei with high nitrilase activity was screened from natural environment and could selective convert nitrile into carhoxylic acid. The catalytic properties of free cells was investigated, including heat stability, pH stability, effects of metallic ions and additives, effects of solvents and substrate specificity and so on. At 45℃ and pH 6.8 the bioeatalyst showed the highest activity, and it kept stability at 20℃and pH 6. 5 - pH 8.5. The enzyme activity was accelerated by Mg^2＋ , Mn^2＋ and surfactant OP, NP10 and RSO10, but inhibited strongly by Fe^3＋ , Cu^2＋ ,Al^3＋ ,Sn^2＋ and sodium dodecylsulfonate. L-cysteine oould weaken the inhibition of the heavy metallic ions . The enzyme oould accept aromatic or aliphatic nitriles, unsaturated or unsaturated nitriles as substrates with high enantioselectivity, Organic solvents denatured or deactivated the biocatalyst, however when it was suspended in an aqueous solution oontaining 6 % （V/V） methanol, the residual activity was 98.8 % after 20 h.

关 键 词：腈水解酶 微生物 游离细胞 催化特性 

分 类 号：TQ920.1[轻工技术与工程—发酵工程]