Enhanced Antibacterial and Anti-Inflammatory Efficiency of Serratiopeptidase Immobilized on CMC-Silver Nanoparticles

In the present study, sunlight-mediated Carboxymethyl cellulose silver nanoparticles (CMC-AgNPs) have been synthesized as a carrier for serratiopeptidase immobilization. Morphological behavior of CMC-AgNPs, crystallinity and functional group identification were evaluated using scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy, respectively. The prepared nanoparticles (NPs) were also subjected to zeta potential, which disclosed the zeta potential value of about-36.06 mV, suggesting their negative charge surface, good stability and polydispersity. SRP was immobilized on synthesized NPs through covalent adsorption using glutaraldehyde as a crosslinker. Immobilized (CMC/Ag-SRP) exhibited 80.95% immobilization efficiency and 79.73% immobilization yield, respectively. Remarkably greater relative activities at broader temperature and pH ranges were attained by SRP after immobilization in comparison to its free counterpart. The K_m value was significantly higher for immobilized enzyme, whereas V_max value was conspicuously lower, indicating that less enzyme was sufficient to achieve maximum velocity. The greater zone of inhibition was displayed by immobilized CMC-AgNPs than that of native NPs against both gram-positive Listeria monocytogenes (12 ± 0.05 mm) and gram-negative Escherichia coli (22 ± 0.12 mm). The bigger zone on casein agar plates for immobilized NPs confirms enhanced caseinolytic activity in comparison to starting materials. In Vitro anti-inflammatory assessment of CMC/Ag-SRP presented more potency than the native NPs, which was comparable to the standard drug. Reusability data demonstrated 50% of initial activity was retained after seven successive cycles. Thereby, it is concluded that incorporation of serratiopeptidase onto CMC-AgNPs presented enhanced effects at lower concentrations with improved anti-inflammatory activity.