Production of N-acetyl chitobiose from various chitin substrates using commercial enzymes

N-acetyl chitobiose was produced by partial hydrolysis of the marine biopolymer chitin using industrially bulk-produced enzyme preparations. Pepsin showed the highest chitinolytic activity. Pepsin treatment of chitin at pH 5.4 at 44 °C yielded 71.5% of chitobiose, 19% of N-acetyl glucosamine and 9.5% chitotriose after incubation during 24 h. Suspensions of amorphous chitin and phosphoric decrystallized chitin were found to be the best substrates. From kinetic studies, it was concluded that the amount of enzyme used is in excess. The substrate is present in excess as well, because only a small part of the substrate is converted. The results suggest that only a small fraction of the glycosidic bonds in decrystallized chitin is available for enzymatic attack. This suggestion is supported by additional enzymatic hydrolysis observed after dissolution and precipitation of already used substrate.