title: Increasing succinic acid production using the PTS-independent glucose transport system in a Corynebacterium glutamicum PTS-defective mutant.
abstract: Succinic acid synthesized from glucose shows potential as a bio-based platform chemical. However, the need for a high glucose concentration, and the accompanying low yields, limit its industrial applications. Despite efficient glucose uptake by the phosphotransferase system (PTS), 1 mol of phosphoenolpyruvate is required for each mole of internalized glucose. Therefore, a PTS-defective Corynebacterium glutamicum mutant was constructed to increase phosphoenolpyruvate availability for succinic acid synthesis, resulting in a lower glucose utilization rate and slower growth. The transcriptional regulator iolR was also deleted to enable the PTS-defective mutant to utilize glucose via iolT-mediated glucose transport. Deletion of iolR and overexpression of iolT1 and ppgk (polyphosphate glucokinase) in the PTS-deficient C. glutamicum strain completely restored glucose utilization, increasing production by 11.6% and yield by 32.4% compared with the control. This study revealed for the first time that iolR represses the expression of the two glucokinase genes (glk and ppgk).
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing, 211816, China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Zhou
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.forename: Hongtao
authors.initials: H
authors.lastname: Xu
authors.forename: Zhongjun
authors.initials: Z
authors.lastname: Chen
authors.forename: Heng
authors.initials: H
authors.lastname: Cai
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport; D050260:Carbohydrate Metabolism; D048230:Corynebacterium glutamicum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005941:Glucokinase / Q000235:genetics / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D060847:Metabolic Engineering; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics*; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism; D019802:Succinic Acid / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D019802:Succinic Acid; D010770:Phosphotransferases; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D005941:Glucokinase; C024812:polyphosphate-glucose phosphotransferase; D005947:Glucose