Extracellular green synthesis of chitosan-silver nanoparticles using Lactobacillus reuteri for antibacterial applications

In this work, we report the eco-friendly green synthesis of hybrid chitosan-silver nanoparticles (CS-AgNPs) using Lactobacillus reuteri ATCC 55730. The cell free extracellular biomass of L. reuteri was used as a reducing and capping agent for the synthesis of CS-AgNPs. The synthesized CS-AgNPs were characterized by using UV-visible spectroscopy, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy, and fourier transform infrared spectroscopy (FTIR). The formation of brown color and UV-visible absorbance peak (lambda(max)) at 415 nm confirmed the synthesis of CS-AgNPs. XRD analysis revealed the face centred cubic crystalline structure of CS-AgNPs. FE-SEM analysis showed that the synthesized CS-AgNPs having quasi-spherical shaped nanostructure with an average size of 40-90 nm. The IR bands at 1465, 1543 and 1651 cm(-1) indicated the presence of amine groups (-NH2), which confirmed the presence of CS in synthesized CS-AgNPs. The synthesized CS-AgNPs showed potential disc diffusion antibacterial activity against B. subtilis and E. coli pathogens. Furthermore, cotton fabrics impregnated with CS-AgNPs also showed bactericidal zone of inhibition against B. subtilis. Thus, the obtained results exposed that the synthesized CS-AgNPs using L. reuteri can be used against bacterial pathogens in textile industries.