ABSTRACT
Fresh vegetables are potential source of lactic acid bacteria (LAB). In the present study, LAB were isolated from the fresh vegetables from Pune region. Total 266 LAB were isolated from the edible parts of fresh vegetables viz. cauliflower, gherkins, cluster beans, fenugreek, cow pea, bitter gourd, french beans, tomato, ridged gourd, cucumber and bottle gourd. On phenotypic and molecular characterization predominant genera obtained were Lactobacillus, Enterococcus and Weissella. Twenty one isolates exhibited tolerance to bile salt, acidic pH and pancreatin. Cellular extracts of several isolates with ability to survive in artificial intestinal condition additionally showed antioxidant potential and cell free supernatants exhibited antibacterial potential against selected plant and human pathogens. Bacteriocin and bacteriocin like substances (BLS) substances secreted by these isolates can be used for food preservation.
ABSTRACT
Gold nanoparticles (Au-NPs) were synthesized from chloroauric acid using cell free supernatant of Streptomyces sp. NK52 grown in nutrient broth. These nanoparticles were synthesized by varying pH and temperature of the reaction mixture and chloroauric acid concentration. The nanoparticles were characterized by spectrometry, X-ray diffraction, Scanning electron microscopy and energy dispersive spectrometry. Au-NP ranged from 10-100 nm in size and exhibited a polydispersive nature with various shapes like rods, hexagons, triangles, spheres. The diffraction peaks at 2θ = 38.1◦ and 44.5◦ could be assigned to the (1 1 1) and (2 0 0) planes of a faced centre cubic (fcc) lattice of gold. Au-NP showed 47% inhibition of lipid peroxidation in vitro. To the best of our knowledge, this is the first report on the rapid biosynthesis of Au-NP using cell free supernatant of Streptomyces sp. and its evaluation for anti-lipid peroxidation.