PRODUCTION OF N-ACETYLCHITOOLIGOSACCHARIDES BY AEROMONAS SP. DYU-TOO 7

Aeromonas sp. DYU‐Too 7 was screened to produce chitinases. The enzymes had an optimal reaction temperature of 50C and an optimal pH of 7.0. The best concentration of chitin in the fermentation process is 4%. Higher concentrations of chitin inhibited microbial growth and influenced the production of reducing sugars, the enzymatic activity and the protein content in the culture. N‐acetylglucosamine, the main product in the hydrolysate, was 0.7 g/L at 36 h of cultivation. The concentration of N‐acetylchitobiose was 0.16 g/L for the regular chitin broth and 0.28 g/L for the phosphorus‐limiting chitin broth, with the highest concentration of N‐acetylchitohexaose at about 0.062 g/L in both media. Experimental results showed that cultivation under a phosphorus‐limiting condition substantially reduced the production of biomass, chitinases as well as N‐acetylchitooligosaccharides.