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Rewiring the Glucose Transportation and Central Metabolic Pathways for Overproduction of N ‐Acetylglucosamine in Bacillus subtilis
Author(s) -
Gu Yang,
Deng Jieying,
Liu Yanfeng,
Li Jianghua,
Shin Hyundong,
Du Guocheng,
Chen Jian,
Liu Long
Publication year - 2017
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201700020
Subject(s) - pep group translocation , bacillus subtilis , metabolic engineering , biochemistry , pentose phosphate pathway , overproduction , biology , two component regulatory system , metabolic pathway , glucose transporter , citric acid cycle , glycolysis , phosphoenolpyruvate carboxykinase , enzyme , gene , bacteria , genetics , microbiology and biotechnology , mutant , insulin
N ‐acetylglucosamine (GlcNAc) is an important amino sugar extensively used in the healthcare field. In a previous study, the recombinant Bacillus subtilis strain BSGN6‐P xylA ‐ glmS‐ pP43NMK ‐GNA1 (BN0‐ GNA1 ) had been constructed for microbial production of GlcNAc by pathway design and modular optimization. Here, the production of GlcNAc is further improved by rewiring both the glucose transportation and central metabolic pathways. First, the phosphotransferase system (PTS) is blocked by deletion of three genes, yyzE (encoding the PTS system transporter subunit IIA YyzE), ypqE (encoding the PTS system transporter subunit IIA YpqE), and ptsG (encoding the PTS system glucose‐specific EIICBA component), resulting in 47.6% increase in the GlcNAc titer (from 6.5 ± 0.25 to 9.6 ± 0.16 g L −1 ) in shake flasks. Then, reinforcement of the expression of the glcP and glcK genes and optimization of glucose facilitator proteins are performed to promote glucose import and phosphorylation. Next, the competitive pathways for GlcNAc synthesis, namely glycolysis, peptidoglycan synthesis pathway, pentose phosphate pathway, and tricarboxylic acid cycle, are repressed by initiation codon‐optimization strategies, and the GlcNAc titer in shake flasks is improved from 10.8 ± 0.25 to 13.2 ± 0.31 g L −1 . Finally, the GlcNAc titer is further increased to 42.1 ± 1.1 g L −1 in a 3‐L fed‐batch bioreactor, which is 1.72‐fold that of the original strain, BN0 ‐GNA1 . This study shows considerably enhanced GlcNAc production, and the metabolic engineering strategy described here will be useful for engineering other prokaryotic microorganisms for the production of GlcNAc and related molecules.