中文摘要：

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，K2HP040．5，KH2PO40．5，氨基酸混合液（包括L—Met、L—Val、L—lie、L—Glu）0．6，pH7．2，所产转氨酶的转化得率达到72．4％。

英文摘要：

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 %.