SELECTING AND INVESTIGATING THE EFFECTS OF ENVIRONMENT ON CHARACTERISTICS OF CHITINASE FROM SOIL FUNGI

Abstract

Chitinase is the second-largest enzyme group in the world after cellulase, it has wide applications in many fields of agriculture, industry, and medicine. Chitooligosaccharides, the chitin hydrolyzed products by chitinase, have many medical properties such as antibacterial activity, anti-cancer, antioxidant and immunostimulating. This study was conducted with the aim of selecting a fungus strain with the highest chitinase biosynthesis ability from the soil and investigating some factors affecting chitinase activity. The selection process was conducted by culturing the fungi on M0 medium for 14 days. We found a fungus strain with the best chitinase biosynthesis based on raw chitinase activity. This fungus strain was identified via the 28S rRNA gene sequencing as Aspergillus sydowii. The factors affecting the culture medium on chitinase activity were investigated including types of culture medium (MT1, MT2, MT3, MT4, MT5), chitin content (0-20%), seed rate of 1-3% (v/w), carbon source (glucose, starch, yellow sugar is 0.2, 0.4, 0.6 g/10.5g medium, respectively), culture time (24- 96 hours). The results showed that the good conditions for biosynthesis of chitinase from Aspergillus sydowii were deternined: MT4 medium with 1 mL seedling rate, percentage of chitin is 15%, culture time was 48 hours and carbon source was brown sugar with 0.6 g (w/w). Activity of obtained chitinase was 1,667 UI/mL.
Keywords: Aspergillus sydowii, chitinase, chitin, carbon source.