【摘要】 运用“单一组分缺失法”研究了18种氨基酸,11种维生素,8种微量元素,4种嘌呤与嘧啶对大肠杆菌A5发酵产转氨酶的影响。结果表明,L-甲硫氨酸是菌体生长与产酶所必需的物质,L-缬氨酸、L-异亮氨酸和L-谷氨酸分别对菌体生长和酶转化得率的提高有显著的促进作用。在此基础上构建了一个改良的合成培养基,其组成为(g/L):葡萄糖20,(NH4)2SO45,MgSO40.5,NaCl0.5,K2HPO40.5,KH2PO40.5,氨基酸混合液(包括L-Met、L-Val、L-Ile、L-Glu)0.6,pH7.2,所产转氨酶的转化得率达到72.4%。更多还原

【Abstract】 Aminotransferase was a key enzyme for the enzymatic preparation of L-phenylalanine. In this paper, using the complete chemically defined medium, the single-omission technique was applied to investigate the effects of 18 kinds of amino acid, 11 kinds of vitamin, 8 kinds of trace element and 4 kinds of purine and pyrimidine on fermentation of aminotransferase. As a conclusion, L-Methionine was the only essential compound for both the growth of Escherichia coli A5 and production of aminotransferase, L-Valine, L-Isoleucine and L-Glutamic acid was sufficiently useful for growth of the strain and preparation of the enzyme respectively. Based on the nutritional requirements, a modified chemically defined medium was formulated to testify the validity of the results, contained（g/L） glucose 20,（NH₄）₂SO₄ 5,MgSO₄ 0.5,NaCl 0.5,K₂HPO₄ 0.5,KH₂PO₄ 0.5,L-Met 0.6, L-Val 0.6, L-Ile 0.6, L-Glu 0.6,pH 7.2, the yield of L-Phenylalanine in MCDM was 72.4%.更多还原