title: Insights into the role of glucose and glycerol as a mixed carbon source in the improvement of ε-poly-L-lysine productivity.
abstract: Using glucose-glycerol mixed carbon source has proved to be an effective strategy for ε-poly-L-lysine (ε-PL) production with rapid cell growth and much higher ε-PL productivity. In this study, we attempt to focus on key enzymes and intracellular energy cofactors to reveal the underlying mechanisms involved in such significant improvements. The activities of key enzymes involved in the pentose phosphate pathway, TCA cycle, anaplerotic pathway and the aspartate family amino acid biosynthesis pathway as well as ε-PL synthetase showed overall enhancement with the mixed carbon source, especially in the late stages of fermentation, compared with those in either glucose or glycerol single carbon sources. Moreover, the intracellular cofactors in terms of NADH and ATP kept higher formation and consumption rates in the mixed carbon source, respectively, throughout batch fermentation. As a result, Streptomyces sp. M-Z18 could be accelerated in cell growth and precursor L-lysine biosynthesis in the mixed carbon source, thus finally shortening fermentation time and enhancing ε-PL productivity. Understanding this process will provide information for the rational regulation of the metabolism network of the quantative production of ε-PL by metabolic engineering.
authors: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
authors: Xin
authors: X
authors: Zeng
authors: Xu-Sheng
authors: XS
authors: Chen
authors: Xi-Dong
authors: XD
authors: Ren
authors: Qing-Rui
authors: QR
authors: Liu
authors: Liang
authors: L
authors: Wang
authors: Qi-Xing
authors: QX
authors: Sun
authors: Lei
authors: L
authors: Tang
authors: Zhong-Gui
authors: ZG
authors: Mao
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D053898:Biosynthetic Pathways; D002244:Carbon / Q000378:metabolism; D003470:Culture Media / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D011107:Polylysine / Q000096:biosynthesis*; D013302:Streptomyces / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D011107:Polylysine; D002244:Carbon; D005947:Glucose; D005990:Glycerol