Biocontrol potential of Vibrio maritimus chitinase: Heterologous expression and insecticidal activity against Acanthoscelides obtectus

In this study, the chitinase gene from the marine bacterium Vibrio maritimus was heterologously expressed in Escherichia coli, purified via affinity chromatography and tested for its insecticidal activity against the storage pest Acanthoscelides obtectus. The recombinant VmChiA protein exhibited a molecular mass of similar to 60 kDa, with optimum activity observed at pH 6.0 and 40 degrees C. Enzyme kinetic analysis revealed a K-m value of 0.042 mM, V-max of 17.48 mu mol min(-1), k(cat) of 1.75 min(-1) and catalytic efficiency of 41.61 mM(-1) min(-1), respectively. Furthermore, a dose of 40 U mL(-1) of recombinant VmChiA showed similar efficacy to malathion insecticide against A. obtectus, with 100 % mortality in both treatments. LC50 and LC90 values of VmChiA were 13.95 U mL(-1) and 27.66 U mL(-1), respectively. Furthermore, the three-dimensional structure of the catalytic site of VmChiA was modeled. Molecular dynamics simulation technique was used to explore and analyze the dynamics and interactions. A salt bridge (GLU274-ARG296) in the alpha + beta domain was observed as a critical feature facilitating substrate (GlcNAc)(2) binding and enzymatic activity. These findings demonstrate that recombinant VmChiA possesses potent insecticidal properties, highlighting its potential as a bio-based, eco-friendly alternative for managing significant agricultural pests.