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头孢类抗生素由于广谱性和低毒性被广泛用于细菌感染的治疗。7-氨基-3-脱乙酰氧基头孢烷酸(7-aminodeacetoxycephalosporanic acid,7-ADCA)作为半合成头孢类抗生素的重要中间体,需求量逐渐增加,而7-ADCA主要由G-7-ADCA(苯乙酰-7ADCA)脱酰基得到。工业上多以化学法合成G-7-ADCA,成本高,污染严重。迫切需要对环境友好且经济高效的合成方法。在前期研究中,构建了一株可以将青霉素G转化为G-7-ADCA的代谢工程菌(E.coli H7/PG15)。本研究通过单因素试验对E.coli H7/PG15的G-7-ADCA合成过程进行优化,包括底物组成及其最适浓度,转化条件(菌体浓度、p H、青霉素浓度、MOPS浓度、葡萄糖浓度,铁离子浓度和时间等)。优化后,建立了全细胞催化法生产G-7-ADCA的工艺流程,使G-7-ADCA的产量稳定在15 mmol/L左右,转化率达到30%,具有操作简便、高效和经济的优势。
Cephalosporin antibiotics are widely used in the treatment of bacterial infections due to their broad spectrum and low toxicity. 7-Amino-3-deacetoxycephalosporanic acid (7-ADCA) as an intermediate for the synthesis of semisynthetic cephalosporins, the demand gradually increased, while the 7-ADCA mainly by the G-7-ADCA (Phenylacetyl-7ADCA). Industrial synthesis of G-7-ADCA and more, high cost, serious pollution. There is an urgent need for environmentally friendly and cost-effective synthesis methods. In the previous study, we constructed a strain of E. coli H7 / PG15 that converts penicillin G to G-7-ADCA. In this study, the synthesis of G-7-ADCA in E. coli H7 / PG15 was optimized by single factor experiment, including substrate composition and its optimum concentration, transformation conditions (cell concentration, p H, penicillin concentration, MOPS concentration, Glucose concentration, iron ion concentration and time, etc.). After optimization, the technological process of G-7-ADCA production by whole cell catalysis was established, the yield of G-7-ADCA was stabilized at about 15 mmol / L and the conversion rate reached 30%, which was easy to operate, high efficiency and economical .