关键词: 基因组改组, 核黄素, 基因扩增, 代谢通量分析

Abstract: Traits of riboflavin-producing B.subtilis 24/pMX45 were improved by genome shuffling and DNA recombination.Riboflavin operon of B.subtilis 24 was integrated within chromosome of B.subtilis and was amplified to multi-copies,and B.subtilis RH33/pMX45 were obtained after two rounds of genome shuffling.The strain produced about 100% more riboflavin than the original strain B.subtilis 24/pMX45 in batch culture with 12% glucose as carbon source.In addition, the strain showed some promising traits such as quick assimilation of glucose, rapid growth, competence development and capablity of gene integration and amplification.Subsequently, the metabolic flux distribution in batch culture of three riboflavin-producing B.subtilis were compared and analyzed.The results of flux analysis and experiment indicate that the primary limiting factor for improvement of riboflavin production in B.subtilis RH33/pMX45 lies in the reactions between 5-P-ribulose and GTP.

Key words: 基因组改组, 核黄素, 基因扩增, 代谢通量分析