摘要
L-苯甘氨酸是合成多种抗生素和抗癌药物的重要中间体,目前主要通过化学法合成.利用蜡样芽孢杆菌来源的亮氨酸脱氢酶(LeuDH)催化苯乙酮酸的还原氨基化合成L-苯甘氨酸,并偶联甲酸脱氢酶(FDH)进行辅酶再生,建立了一种新型的苯甘氨酸生物合成方法.结果表明,该辅酶再生体系可有效地用于L-苯甘氨酸的合成,且没有副产物残留,辅底物甲酸铵还可提供还原氨基化所需NH4+,随后对酶转化条件进行优化,最适转化条件为苯乙酮酸60 g/L,甲酸铵50.4 g/L,LeuDH 4 U/mL,FDH 2 U/mL,NAD+浓度0.14 g/L,p H 8.0以及30℃.在最优条件下,1 L的转化体系中,转化反应5 h,苯乙酮酸转化率达到99%,L-苯甘氨酸产量60.2 g/L,ee值>99%.本研究为L-苯甘氨酸的工业生产提供了一种更加简单、高效、经济的生物合成途径.(图8表4参27)
L-phenylglycine, an important intermediate in the synthesis of various antibiotics and anticancer drugs, is currently mainly synthesized through chemical methods. In this study, a new biological synthesis method for L-phenylglycine was developed. Leucine dehydrogenase(LeuDH) from Bacillus cereus was used to catalyze the reductive amination of benzoylformic acid for L-phenylglycine synthesis, and formate dehydrogenase(FDH) was used for cofactor regeneration. The results showed that the cofactor regeneration system was effective for the synthesis of L-phenylglycine without any by-products, and the reaction cosubstrate ammonium formate further provided the ammonium ions(NH_4~+) required for reductive amination. The enzymatic transformation conditions were then optimized to improve conversion efficiency. The obtained optimal conversion conditions were: benzoylformic acid 60 g/L, ammonium formate 50.4 g/L, LeuDH 4 U/mL, FDH 2 U/mL, NAD+ concentration0.14 g/L, pH 8.0, and a temperature of 30 ℃. Finally, under these optimal conditions, a 99% conversion rate was achieved in 5 h with the yield of 60.2 g/L, and an ee value > 99% at 1 L scale. This study, therefore, provides a simplified, more efficient and economical biosynthetic method for L-phenylglycine production.
引文
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