Kinetic, Thermodynamic and Bio-applicable Studies on Aspergillus niger Mk981235 Chitinase

Abstract Chitinases have many applications in food, agricultural, medical, and pharmaceutical fields. This study succeeded in investigating Aspergillus niger MK981235 chitinase in the spot of its physiochemical, kinetic, thermodynamic, and application. The optimum temperature, pH and p-nitrophenyl-β- d -N-acetyl glucosaminide (PNP-β-GlcNAc) concentration to obtain the highest chitinase activity of 2334.79 U ml −1 were at 60 °C, 5 and 0.25%, respectively. The kinetic parameters, including K m and V max were determined to be 0.78 mg ml −1 and 2222.22 µmol ml −1 min −1 , respectively. Furthermore, the thermodynamic parameters T 1/2 , D-values, ΔH, ΔG and ΔS at 40, 50 and 60 °C were determined to be (864.10, 349.45, 222.34 min), (2870.99, 1161.07, 738.74 min), (126.40, 126.36, 126.32 kJ mol −1 ), (101.59, 100.62, 100.86 kJ mol −1 ), (74.50, 76.17, 47.24 J mol −1 K −1 ), respectively. A. niger chitinase showed, insecticidal activity on Galleria mellonella by feeding and spraying treatments (72 and 52%, respectively), anti-lytic activity against Candida albicans , and effectiveness in improving the dye removal in the presence of crab shell powder as bio-absorbant. A. niger chitinase can be used in the pharmaceutical field for the bio-control of diseases caused by C. albicans and for the pretreatment of wastewater from the textile industry. Graphical Abstract