Authors: Yan Liu Guihua Gong Liping Xie Ning Yuan Chunbao Zhu Baoquan Zhu Youjia Hu
Publish Date: 2009/09/29
Volume: 44, Issue: 2, Pages: 101-109
Abstract
Cephalosporins are widely used as antiinfectious βlactam antibiotics in clinic For the purpose of increasing the yield of cephalosporin C CPC fermentation especially in an industrial strain A chrysogenum genes cefEF and cefG which encode the ultimate and penultimate steps in CPC biosynthesis cefT which encodes a CPC efflux pump and vgb which encodes a bacterial hemoglobin gene were transformed in various combinations into an industrial strain of A chrysogenum Both PCR and Southern blotting indicated that the introduced genes were integrated into the chromosome of A chrysogenum Carbon monoxide difference spectrum absorbance assay was performed and the result showed that Vitreoscilla hemoglobin was successfully expressed in A chrysogenum and had biological activity HPLC analysis of fermentation broth of recombinant A chrysogenum showed that most transformants had a higher CPC production level than the parental strain Multiple transformants containing an additional copy of cefG showed a significant increase in CPC production However cefT showed little effect on CPC production in this high producer The highest improvement of CPC titer was observed in the mutant with an extra copy of cefG + cefEF + vgb whose CPC production was increased by 1163 This was the first report that three or more genes were introduced simultaneously into A chrysogenum Our results also demonstrated that the combination of these genes had a synergy effect in a CPC high producer
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