The Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
J Ind Microbiol Biotechnol. 2012 Feb;39(2):269-74. doi: 10.1007/s10295-011-1025-5. Epub 2011 Aug 25.
Deacetoxycephalosporin C (DAOC) is not only the precursor but also one of the by-products during cephalosporin C (CPC) biosynthesis. One enzyme (DAOC/DAC synthase) is responsible for the two-step conversion of penicillin N into deacetylcephalosporin C (DAC) in Acremonium chrysogenum, while two enzymes (DAOC synthase and DAOC hydroxylase) were involved in this reaction in Streptomyces clavuligerus and Amycolatopsis lactamdurans (Nocardia lactamdurans). In this study, the DAOC hydroxylase gene cefF was cloned from Streptomyces clavuligerus and introduced into Acremonium chrysogenum through Agrobacterium tumefaciens-mediated transformation. When cefF was expressed under the promoter of pcbC, the ratio of DAOC/CPC in the fermentation broth significantly decreased. These results suggested that introduction of cefF could function quite well in Acremonium chrysogenum and successfully reduce the content of DAOC in the CPC fermentation broth. This work offered a practical way to improve the CPC purification and reduce its production cost.
去乙酰氧基头孢菌素 C（DAOC）不仅是头孢菌素 C（CPC）生物合成的前体，也是其中一种副产物。在顶头孢霉中，一种酶（DAOC/DAC 合酶）负责青霉素 N 两步转化为去乙酰头孢菌素 C（DAC），而在棒状链霉菌和乳杆菌放线菌（诺卡氏放线菌）中，两种酶（DAOC 合酶和 DAOC 羟化酶）参与了这一反应。在这项研究中，我们从棒状链霉菌中克隆了 DAOC 羟化酶基因 cefF，并通过根癌农杆菌介导的转化将其引入顶头孢霉。当 cefF 在 pcbC 启动子的控制下表达时，发酵液中 DAOC/CPC 的比例显著降低。这些结果表明，cefF 的引入可以在顶头孢霉中很好地发挥作用，并成功降低 CPC 发酵液中 DAOC 的含量。这项工作为提高 CPC 的纯度和降低其生产成本提供了一种实用的方法。
