一种深海微生物脂肪酶在非水介质中催化合成乙酸肉桂酯的应用研究
Synthesis of cinnamyl acetate by lipase- catalyzed trans- esterification
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摘要: 从一株深海来源微生物Streptomyces sp.SCSIO 13580的基因组中克隆了1个序列新颖的脂肪酶编码基因,含有1005个碱基,编码334个氨基酸,与最相近的蛋白有51%相似。在大肠杆菌中异源表达了这个脂肪酶,发现其具有在非水介质中催化合成乙酸肉桂酯的活性。在单因素实验的基础上,考察了酰基供体、溶剂、肉桂醇/乙酸乙烯酯摩尔浓度之比、温度等因素对该酶合成乙酸肉桂酯的活性的影响,得到的最佳反应条件是:以乙酸乙烯酯为酰基供体,以正己烷为溶剂,肉桂醇/乙酸乙烯酯的摩尔浓度之比为1∶6,反应温度为40℃,优化后的转化率达到48.3%,酶粉的酶活力为5.59 U/g。Abstract: One novel gene encoding a lipase L- 1 was cloned from the genome of Streptomyces sp.SCSIO 13580 identified from the deep sea of the South China Sea.L- 1 contains 1005 bp and encodes a putative lipase that harbors 334 amino acids and exhibits the highest similarity of 51% with other lipases.The lipase was heterologously expressed in E.coli.The lipase could catalyze the trans- esterification reaction of vinyl acetate and cinnamyl alcohol in non- aqueous medium.The effects including cinnamyl alcohol / vinyl acetate ratio( mol / mol),temperature,solvents and aclyl donors,on the catalytic activities were further investigated.The optimum enzymatic working conditions were obtained as follows: vinyl acetate as the acyl donor,n- hexane as the solvent,ratio of cinnamyl alcohol / vinyl acetate 1 ∶ 6,reaction temperature of 40 ℃,the maximum conversion rate could reach 48.3%,the activity of enzyme powder was 5.59 U / g.