Highly Efficient Production of N-Acetyl-glucosamine in Escherichia coli by Appropriate Catabolic Division of Labor in the Utilization of Mixed Glycerol/Glucose Carbon Sources

Abstract

Currently, microbial production is becoming a competitive method for N-acetyl-glucosamine production. As the biosynthesis of N-acetyl-glucosamine originating from fructose-6-P directly competes with central carbon metabolism for precursor supply, the consumption of glucose for cell growth and cellular metabolism severely limits the yield of N-acetyl-glucosamine. In this study, appropriate catabolic division of labor in the utilization of mixed carbon sources was achieved by deleting the pf kA gene and enhancing the utilization of glycerol by introducing the glpK mutant. Glycerol thus mainly contributed to cell growth and cellular metabolism, and more glucose was saved for efficient N-acetyl-glucosamine synthesis. By optimizing the ratio of glycerol to glucose, the balancing of cell growth/cellular metabolism and N-acetyl-glucosamine synthesis was achieved. The resulting strain GLALD-7 produced 179.7 g/L N-acetyl-glucosamine using mixed glycerol/glucose (1:8, m/m) carbon sources in a 5 L bioreactor, with a yield of 0.458 g/g total carbon sources (0.529 g/g glucose) and a productivity of 2.57 g/L/h. Coherent high titer/yield/productivity was obtained, with the highest values ever reported, suggesting that an appropriate catabolic division of labor using mixed glycerol/ glucose carbon sources is a useful strategy for facilitating the microbial production of chemicals originating from glucose or metabolites upstream of glycolysis.

Metabolic Engineering of Escherichia coli for Increased Bioproduction of N-Acetylneuraminic Acid

“…To further improve NeuAc production, we knocked out several genes involved in the key metabolic nodes of competing pathways to block interference with NeuAc synthesis. By analyzing the metabolic pathway, first, Fru-6P was found to be an important precursor for NeuAc synthesis. , To divert more carbon flux from central carbon metabolism and other competing pathways into NeuAc production at the Fru-6P node, the pfkA gene responsible for 90% of the 6-phosphofructokinase activity and the manA gene, encoding mannose 6-phosphate isomerase, were selected for knockout. Second, UDP- N -acetylglucosamine 2-epimerase, encoded by wecB , can isomerize UDP-GlcNAc, another key precursor for NeuAc synthesis, into UDP- N -acetyl-mannosamine (UDP-ManNAc), which greatly hampers UDP-GlcNAc accumulation in the NeuAc biosynthesis pathway.…”

Polyoxometalate‐Based Metal Organic Frameworks: Recent Advances and Challenges

“…Ethylene, an important component of plastics production, is mainly produced commercially by the petroleum industry [42] . The technology of acetylene semi‐hydrogenation to olefins is of great significance in the field of purification of ethylene [43,44] .…”

“…Ethylene, an important component of plastics production, is mainly produced commercially by the petroleum industry. [42] The technology of acetylene semi-hydrogenation to olefins is of great significance in the field of purification of ethylene. [43,44] Based on this, Liu et al [45] constructed separated single Pd atoms in POMOF to achieve highly selective acetylene semihydrogenation in an ethylene-containing gas stream (Figure 6).…”

Eliminating host-guest incompatibility via enzyme mining enables the high-temperature production of N-acetylglucosamine

“… 37 Currently, the reported GNA1s are mostly derived from mesophiles, such as yeasts, which limits the host options for microbial fermentation. 38 , 39 , 40 , 41 To date, the strains used for GlcNAc production include Escherichia coli , 42 Saccharomyces cerevisiae , 43 Bacillus subtilis , 44 and Corynebacterium glutamicum . 45 Despite great achievements in using these hosts, the mesophilic fermentation conditions (≤37°C) remain the problems of higher energy consumption and cost.…”