摘要
为研究酶法生产L-苯丙氨酸工艺中影响收率的主要因素，提高L-苯丙氨酸的收率，对该反应过程的动力学进行了研究。研究中采用实验检测和动力学模拟的方法获取了转化反应中的主要动力学参数。研究这些参数和L-苯丙氨酸收率间的关系发现，达到L-苯丙氨酸最大收率的前提条件是草酰乙酸的浓度趋近于0。在此前提条件下，将苯丙酮酸的浓度选在0．10～0、15mol／L，提高体系中酶活性，降低苯丙酮酸的降解常数，可以提高体系中L-苯丙氨酸的收率。以此规律为指导，构建了合适的基因工程菌，其转氨酶活性提高4．6倍，苯丙酮酸的降解常数降低到0．0158h^-1，选择c（苯丙酮酸）=0．137mol／L充N2的条件下进行反应，其L-苯丙氨酸收率提高到90．2％。
In order to know the main factors of productivity of L-phenylalanine by E. coli aspartate aminotransferase and increase the productivity of L-phenylalanine, some kinetic parameters were studied in this process. These important parameters were acquired by experiment and modeling. The relationship between these parameters and productivity of L-phenylalanine proved that the main factors of productivity were enzyme activity, decomposition parameter of phenylpyruvic acid and concentration of phenylpyruvic acid. Under the condition of c （PPA） = 0. 137 mol/L and N2 protection, a suitable genetic engineering strain was applied for production of L-phenylalanine. The enzyme activity of the genetic engineering strain was 4. 6 times higher than that of phenylalanine-producing strain. And the decomposition parameter of phenylpyruvic acid in the genetic engineering strain decreased to 0. 015 8 h^-1. Thus the productivity of L-phenylalanine increased to 90. 2%.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2007年第6期549-553,570,共6页
Fine Chemicals
基金
国家重大基础研究项目(2003CB716000)
国家自然基金重点项目(20336010)~~
关键词
动力学
天冬氨酸转氨酶
L-苯丙氨酸
生物工程
kinetics
aspartate aminotransferase
L-phenylalanine
biological engineering
