Identification, purification and functional characterization of a thermostable marine chitinase for potential fungal control via chitin degradation mechanism

The growing prevalence of treatment-resistant Candida species highlights an urgent need for innovative antifungal therapies. The current range of antifungals, limited to polyenes, azoles, and echinocandins, are becoming insufficient due to the rise of resistance, including cross-resistance among fungal strains. Marine environment is an underexplored reservoir of unique enzymes which can be extremophilic. This study presents the cloning and expression of a chitinase gene from the bacterium Bacillus thuringiensis (BtChi), expressed in an E. coli system, yielding a protein with a molecular weight of approximately 71 kDa. Disc diffusion and MIC experiments indicated that 5 μg/mL chitinase efficiently suppressed the growth of Candida albicans. Initial characterization identified the optimal activity at 40 °C and pH 7.0. The enzyme retained over 75 % activity across a pH range of 4–8 and a temperature range of 30–70 °C after 120 min. Activity was further enhanced by 24 % with 100 mM Na⁺. Kinetic parameters with colloidal chitin revealed K_m and V_max values to be 0.05 mg/mL and 1.37 U/mL respectively. This study holds the potential of developing a potent natural anti-fungal against the present day chemical counterparts.