（R）-苯乙酰基甲醇酶促生产中丙酮酸效率的提高。

Increased pyruvate efficiency in enzymatic production of (R)-phenylacetylcarbinol.

作者信息

Rosche Bettina, Breuer Michael, Hauer Bernhard, Rogers Peter L

机构信息

School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW 2052, Australia.

出版信息

Biotechnol Lett. 2003 Jun;25(11):847-51. doi: 10.1023/a:1024082424066.

DOI:10.1023/a:1024082424066

PMID:12889792

Abstract

Loss of substrate, pyruvate, a limitation for enzymatic batch production of (R)-phenylacetylcarbinol (PAC), resulted from two phenomena: temperature dependent non-enzymatic concentration decrease due to the cofactor Mg2+ and formation of by-products, acetaldehyde and acetoin, by pyruvate decarboxylase (PDC). In the absence of enzyme, pyruvate stabilization was achieved by lowering the Mg2+ concentration from 20 to 0.5 mM. With 0.5 mM Mg2+ Rhizopusjavanicus and Candida utilis PDC produced similar levels of PAC (49 and 51 g 1(-1), respectively) in 21 h at 6 degrees C; however C. utilis PDC formed less by-product from pyruvate and was more stable during biotransformation. The process enhancements regarding Mg2+ concentration and source of PDC resulted in an increase of molar yield (PAC/consumed pyruvate) from 59% (R. javanicus PDC, 20 mM Mg2+) to 74% (R. javanicus PDC, 0.5 mM Mg2+) to 89% (C. utilis PDC, 0.5 mM Mg2+).

摘要

底物丙酮酸的损失是酶法分批生产（R）-苯基乙酰甲醇（PAC）的一个限制因素，这是由两种现象导致的：由于辅因子Mg2+导致温度依赖性的非酶促浓度降低，以及丙酮酸脱羧酶（PDC）产生副产物乙醛和乙偶姻。在没有酶的情况下，通过将Mg2+浓度从20 mM降低到0.5 mM可实现丙酮酸的稳定。在6℃下，使用0.5 mM Mg2+时，爪哇根霉和产朊假丝酵母的PDC在21小时内产生的PAC水平相似（分别为49和51 g L-1）；然而，产朊假丝酵母的PDC从丙酮酸形成的副产物较少，并且在生物转化过程中更稳定。关于Mg2+浓度和PDC来源的工艺改进导致摩尔产率（PAC/消耗的丙酮酸）从59%（爪哇根霉PDC，20 mM Mg2+）提高到74%（爪哇根霉PDC，0.5 mM Mg2+），再提高到89%（产朊假丝酵母PDC，0.5 mM Mg2+）。