title: Effects of modulation of pentose-phosphate pathway on biosynthesis of ansamitocins in Actinosynnema pretiosum.
abstract: Ansamitocins, produced by Actinosynnema pretiosum, are a group of maytansinoid antibiotics that block the assembly of tubulin into functional microtubules. The precursors of ansamitocin biosynthesis are generally derived from the Embden-Meyerhof-Parnas (EMP) pathway and the tricarboxylic acid cycle. In this study, central carbon flux distributions were analyzed by (13)C-based flux analysis to reveal the contribution of individual central carbon metabolism pathways. To direct more carbon flux into ansamitocin biosynthesis, pentose phosphate (PP) pathway only and the combination of PP pathway and Entner-Doudoroff (ED) pathway were weakened, respectively. Ansamitocin P-3 (AP-3) productions by both kinds of pathways weakened mutant strains were significantly enhanced in chemically defined medium. In order to draw metabolic flux to the biosynthesis of ansamitocins more efficiently, heterologous phosphoglucomutase was subsequently overexpressed based on a mutant strain with combinational regulation of PP pathway and ED pathway. More fluxes were successfully directed into the UDP-glucose synthetic pathway and the AP-3 production was further improved in this case, reaching approximately 185mg/L in fermentation medium. It was demonstrated that eliminating the bypass pathways and favoring the precursor synthetic pathway could effectively improve ansamitocin production by A. pretiosum, suggesting a promising role of metabolic strategy in improving secondary metabolite production.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
authors.forename: Fengxian
authors.initials: F
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
authors.forename: Liujing
authors.initials: L
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Microbial Metabolism and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Linquan
authors.initials: L
authors.lastname: Bai
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Meilong Road, Shanghai 200237, China. Electronic address: qhua@ecust.edu.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Hua
mesh_terms: D039903:Actinobacteria / Q000378:metabolism*; D008453:Maytansine / Q000031:analogs & derivatives* / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways; D010427:Pentose Phosphate Pathway / Q000502:physiology*; D010733:Phosphoglucomutase
chemical_list: D008453:Maytansine; C015682:ansamitocins; D010733:Phosphoglucomutase
keywords: Actinosynnema pretiosum; Ansamitocins; Metabolic engineering; Pentose phosphate pathway; Phosphoglucomutase