Purification, characterization, and antifungal activity of Bacillus cereus strain NK91 chitinase from rhizospheric soil samples of Himachal Pradesh, India

Newly isolated Bacillus cereus strain NK91 was characterized for extracellular chitinase production. Partially purified chitinase showed a molecular weight of 43.7 kDa in SDS-PAGE analysis. The optimum pH and temperature for the partially purified enzyme were 7.0 and 40 degrees C, respectively. The addition of Mn2+ resulted in a 21% increase in enzyme activity as compared to the control. The V-max and K-m of the enzyme were determined as 76.9 mu mol/min and 0.07 mg/mL, respectively. This enzyme exhibited stronger antifungal activity towards Fusarium oxysporum (66.7%), Rhizoctonia solani (64.6%), and Colletotrichum gloeosporioides (63%), and transmission electron microscopy and scanning transmission electron microscopy analysis showed considerable changes in cell wall structure with the treatment of purified chitinase as compared to control. Therefore, this enzyme reveals its biocontrol potential against potent phytopathogens in agriculture that can be helpful in swapping harmful as well as expensive fungicides.

Automated summary

The newly isolated Bacillus cereus strain NK91 produces extracellular chitinase with strong antifungal activity against potential phytopathogens by altering cell wall structure. This enzyme shows promise for biocontrol in agriculture as a potential alternative to harmful and expensive fungicides.