Laccase-mediated catechin grafting to chitosan for modulating antioxidant, antimicrobial activities and controlled release

251st American Chemical Society National Meeting & Exposition - Computers in ChemistryIn the present study, laccase from ascomycete myceliophthora thermophila was used for the simultaneous reactions of catechin oxidation to produce reactive o-quinions and subsequent reaction with free amino groups in chitosan (CS) through Schiff-base and Michael addition types reactions. These reactions were proved by UV-vis and ATR-IR spectroscopy showing the changes of peaks shape or characteristic new peaks appearances. The functionalised chitosan compounds, having a different degree of deacetylation (DDA) like 65, 95%, were further employed to film formations and showed different behaviours in swelling, erosion, thermal, and mechanical properties. The biological activities of antioxidant and antimicrobial were evaluated and showed the improvement of their activities by enzymatic grafting of strong antioxidant, catechin. The controlled release profiles of methylene blue (MB) and coomassie blue (CB) dyes from CS films were also studied and the DDA of CS, types of loading molecules, releasing medium, and the enzymatic grafting of CA were important parameters affecting release profiles of CS films.