Improved oxytetracycline production in Streptomyces rimosus M4018 by metabolic engineering of the G6PDH gene in the pentose phosphate pathway

• Published in: Enzyme and microbial technology Vol. 49; no. 1; pp. 17 - 24
• Main Authors: Tang, Zhenyu, Xiao, Ciying, Zhuang, Yingping, Chu, Ju, Zhang, Siliang, Herron, Paul R., Hunter, Iain S., Guo, Meijin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 10.06.2011; Elsevier
• Subjects: adenosine triphosphate; Base Sequence; Biological and medical sciences; Biomass; Bioreactors - microbiology; Biotechnology; carbon; Carbon Cycle; DNA, Bacterial - genetics; enzyme activity; Fermentation; Fundamental and applied biological sciences. Psychology; gene expression; genes; Genes, Bacterial; glucose-6-phosphate 1-dehydrogenase; Glucose-6-phosphate dehydrogenase; glucose-6-phosphate isomerase; Glucosephosphate Dehydrogenase - genetics; Glucosephosphate Dehydrogenase - metabolism; glycolysis; malonyl coenzyme A; Malonyl-CoA; Metabolic Engineering; mutants; Mutation; NADP (coenzyme); NADPH generation; oxytetracycline; Oxytetracycline - biosynthesis; pentose phosphate cycle; Pentose Phosphate Pathway - genetics; secondary metabolites; Streptomyces - genetics; Streptomyces - growth & development; Streptomyces - metabolism; Streptomyces rimosus; Streptomyces rimosus M4018; Streptomycetes; Glucose-6-phosphate dehydrogenase; Malonyl-CoA; Oxytetracycline biosynthesis; Streptomyces rimosus M4018; NADPH generation; NADPH; Streptomyces rimosus; Glucose-6-phosphate 1-dehydrogenase; Streptomycetaceae; Enzyme; Biosynthesis; Actinomycetales; Oxytetracycline; Gene; Production; Pentose phosphate pathway; Bacteria; Metabolic engineering; Actinomycetes; Oxidoreductases
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2011.04.002

The aromatic polyketide antibiotic, oxytetracycline (OTC), is produced by Streptomyces rimosus as an important secondary metabolite. High level production of antibiotics in Streptomycetes requires precursors and cofactors which are derived from primary metabolism; therefore it is exigent to engineer the primary metabolism. This has been demonstrated by targeting a key enzyme in the oxidative pentose phosphate pathway (PPP) and nicotinamide adenine dinucleotide phosphate (NADPH) generation, glucose-6-phosphate dehydrogenase (G6PDH), which is encoded by zwf1 and zwf2. Disruption of zwf1 or zwf2 resulted in a higher production of OTC. The disrupted strain had an increased carbon flux through glycolysis and a decreased carbon flux through PPP, as measured by the enzyme activities of G6PDH and phosphoglucose isomerase (PGI), and by the levels of ATP, which establishes G6PDH as a key player in determining carbon flux distribution. The increased production of OTC appeared to be largely due to the generation of more malonyl-CoA, one of the OTC precursors, as observed in the disrupted mutants. We have studied the effect of zwf modification on metabolite levels, gene expression, and secondary metabolite production to gain greater insight into flux distribution and the link between the fluxes in the primary and secondary metabolisms.