Biosynthesis of chitooligosaccharides by recombinant Escherichia coli / 生物工程学报

Acetyl-N-glucosaminyltransferase gene (nodC) was successfully cloned to Escherichia coli from Mesorhizobium loti. The recombinant E. coli harboring nodC gene was able to synthesize chitooligosaccharides (COs) in MMYNG medium. In optimized condition, a yield of 526 mg/L was obtained after 26 h cultivation in 10 L bioreactor. COs concentration reached up to 4.5% of the cell dry weight. The COs products were purified by charcoal adsorption and Bio-gel P4 chromatography, penta-N-acetylchitopentaose (m/z, 1034[M + H]+) and tetra-N-acetylchitopentaose (m/z, 831 [M + H]+) were identified as the dominating COs product using the method of liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS).