Production, Characterization and Application of a Novel Chitosanase from Marine Bacterium BP-N07.

Chitooligosaccharides (COS), a high-value chitosan derivative, have many applications in food, pharmaceuticals, cosmetics and agriculture owing to their unique biological activities. Chitosanase, which catalyzes the hydrolysis of chitosan, can cleave β-1,4 linkages to produce COS. In this study, a chitosanase-producing BP-N07 was isolated from marine mud samples. The chitosanase enzyme (CSN) activity was 2648.66 ± 20.45 U/mL at 52 h and was able to effectively degrade chitosan. The molecular weight of purified CSN was approximately 37 kDa. The yield and enzyme activity of CSN were 0.41 mg/mL and 8133.17 ± 47.83 U/mg, respectively. The optimum temperature and pH of CSN were 50 °C and 6.0, respectively. The results of the high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) of chitosan treated with CSN for 3 h showed that it is an endo-chitosanase, and the main degradation products were chitobiose, chitotriose and chitotetraose. CSN was used for the preparation of oligosaccharides: 1.0 mg enzyme converted 10.0 g chitosan with 2% acetic acid into oligosaccharides in 3 h at 50 °C. In summary, this paper reports that CSN has wide adaptability to temperature and pH and high activity for hydrolyzing chitosan substrates. Thus, CSN is a chitosan decomposer that can be used for producing chitooligosaccharides industrially.