Production of antifungal N-acetyl-β-glucosaminidase chitinolytic enzyme using shrimp byproducts

Abstract Shrimp by-products are chitin-rich sources that attract the focus of researchers for their exploitation in several biotechnological fields. In the present study, shrimp byproducts were applied for the cultivation of Penicillum sp. SSW2 under submerged fermentation inducing the production of chitinolytic enzyme. The production of the enzyme was statistically optimized to 15.802U/mL by an increasing fold of 3.29 in which the optimized cultivated fermentation medium composed of (g %) shrimp byproducts, 1; yeast extract, 1.85, K2HPO4, 1.5 and KCl, 0.2 at initial pH 4, was incubated for 10 days at 30οC and 150 rpm. The optimum enzymatic activity of the partially purified enzyme was achieved at pH 6 and 60οC. Additionally, the enzyme retains more than 97% of its maximum activity at 70 °C. The half-lives of the enzyme were estimated as 138.4, 64.6, and 8.7min at 45, 50, and 55οC, respectively. The efficiency of the enzyme was examined at its optimum conditions in the hydrolysis of chitin-oligosaccharides, it was indicated that it possessed N-acetyl-β-glucosaminidase activity confirmed by thin-layer and high-performance liquid chromatography. The Km and Vmax were calculated for chitin hydrolysis as 20 mg/mL and 4.55 mmol/mL/h, respectively. Moreover, a total amount of reducing sugars of 68.8 μg N-acetyl glucosamine/mg was achieved by the hydrolysis of shrimp chitin for 6 h. Finally, the antifungal activity of the partially purified enzyme was estimated against the phytopathogenic fungus Fusarium oxysporum.