Structural Uniformity as a Key Determinant for the Antimicrobial Potency of Chitooligosaccharides

초록

This study aimed to assess how substrate uniformity influences chitosan molecular weight (MW) and its subsequent antibacterial efficacy. The substrate specificity and selectivity of enzymes were evaluated using high-molecular-weight chitosan (HMWC) as the substrate. Chitosanase, chitinase, and cellulase were applied to HMWC, and changes in reducing sugars over time were measured. Enzyme activity was evaluated by measuring the decrease in the molecular weight of HMWC. Among these, the antimicrobial activity of chitooligosaccharides (COS), the hydrolysates of chitinase and chitosanase, was evaluated to confirm significant antimicrobial effects against Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA). To identify distinct differences in growth inhibition or bactericidal action, the MW and range of COS were measured using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry. COS-cs with greater MW uniformity exhibited significantly more antimicrobial or bactericidal effects compared to COS-ct with lower uniformity. Our findings demonstrate that assessing enzyme substrate specificity and component uniformity is a critical determinant in customizing the MW of COS for optimized antibacterial action.

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