巨大芽孢杆菌酶法转化制备D-苯丙氨酸  

Enzymic Conversion of D-Phenylalanine Using Bacillus Megaterium AS1.127

作　　者：贾晓娟[1] 郭丽芸[1] 刘毅[1] 焦庆才[1] 

机构地区：[1]南京大学医药生物技术国家重点实验室,江苏南京210093

出　　处：《化学世界》2006年第5期281-284,289,共5页Chemical World

基　　金：国家技术创新基金资助项目(02CJ-13-01-16)

摘　　要：以DL-苯丙氨酸为底物,利用巨大芽孢杆菌（Bacillus megaterium）AS1.127苯丙氨酸脱氨酶光学异构选择性,仅对L-苯丙氨酸专一氧化脱氨,而不作用于D型,从而高效制备D-苯丙氨酸.考察了影响酶促反应的几种因素,得到了最佳酶促反应条件,结果表明,该转化反应最适温度37～40℃.最适pH 5.8,0.2%磷酸缓冲液可提高脱氨酶活力,在反应液中加入表面活性剂0.2%吐温-80或10^-5mol/L K＋能显著提高脱氨酶活力.转化率与底物浓度、菌体用量有关,在此反应体系中,底物DL-苯丙氨酸浓度0.09mol/L,菌体用量0.03g/mL,转化时间18 h,L-苯丙氨酸转化率最高达98%以上.转化液经脱色、减压浓缩和等电点结晶后得D-苯丙氨酸,比旋光为[α]20D=＋32.4°,光学纯度达到95%以上.Taking DL-phenylalanine as substrate, D-phenylalanine was obtained via using phenylalaine deaminase from Bacillus megaterium ASI. 127, which has the specific oxidative deamination ability for L-phenylalanine. The factors affecting the enzymatic reaction were discussed and the optimum conditions were obtained. The results showed that the optimum temperature was 40℃ and pH was 5.8. The presence of 0.2 mol/L phosphate buffer solution resulted in an enhancement of the enzyme activity. The conversion rate was remarkably enhanced in the presence of 0.2% Tween-80 and 10^-5 mol/L K^＋ .The conversion rate was related with the concentration of both the substrate and the mycelia. When the concentration of the substrate DL-phenylalanine was 0.09 mol/L, the mycelia was 0.03 g/mL and the reaction time was 18 h, the yield was more than 98% . D-phenylalanine was obtained after decoloring of the enzymic reaction solution, concentrating and crystallizing, and its optical purity was higher than 95 %.

关 键 词：D-苯丙氨酸 DL-苯丙氨酸 苯丙氨酸脱氨酶 巨大芽孢杆菌AS1.127 酶转化 

分 类 号：Q93[生物学—微生物学]