In vitro assessment of antifungal activity of chitinase extracted from Bacillus subtilis

Aims: Fungal pathogens significantly threaten human health, crop production and the well-being of plants and animals globally. Bacillus species are recognized for their ability to act as biocontrol agents against detrimental fungal pathogens by enzymatically degrading their cell walls. This ability to control fungal diseases is attributed to the chitinase activity of Bacillus species. This research examined Bacillus subtilis extracellular chitinase and its antifungal potential under in vitro conditions. Methodology and results: The chitinolytic bacterium was isolated from rhizospheric soil and identified through standard microbiological techniques, molecular characterization by PCR and sequencing. The isolated bacterial strain was identified as B. subtilis strain MR21. Extracellular chitinase activity of B. subtilis strain MR21 was observed by using 3% colloidal chitin prepared from shrimp shells. The antifungal activity of chitinase from B. subtilis was determined against pathogenic fungal species, Aspergillus niger and Rhizoctonia solani, , through broth microdilution assay. Extracellular chitinase activity exhibited inhibitory effects when tested against a colloidal chitin medium, with a recorded value of 0.071. The peak optical density (OD) reading was observed at 540 nm using a spectrophotometer. The extracellular chitinase activity exhibited inhibition when tested on a colloidal chitin medium, with the highest optical density (OD) value recorded at 540 nm using a spectrophotometer. Research findings revealed that A. niger was more susceptible to inhibition than R. solani. . Conclusion, significance and impact of study: The chitinase derived from B. subtilis demonstrates antagonistic activity against pathogenic fungi, indicating its potential for treating fungal infections.