Characterization of biosurfactant produced by the endophyte Burkholderia sp. WYAT7 and evaluation of its antibacterial and antibiofilm potentials.

The endophyte Burkholderia sp. WYAT7 isolated from the medicinal plant Artemisia nilagirica (Clarke) Pamp. was analyzed for its ability to produce biosurfactant. The evaluation of biosurfactant production was conducted using different screening methods which confirmed the presence of biosurfactant in the culture supernatant. CTAB- methylene blue agar plate method was used for the screening of glycolipid biosurfactant production. The biosurfactant produced by the bacteria effectively metabolized hydrocarbons present in the bacterial culture media. Fourier transform infrared spectroscopic (FTIR) analysis of biosurfactant provided the details regarding OH stretching, stretching vibrations of acyl chain, CO stretching, stretching vibrations of ether and vibrations of glycosidic linkages in the biosurfactant. The stretching vibrations of glycosidic linkage in the fingerprint regions of FTIR spectrum (1200 cm-1 to 800 cm-1 regions) confirms that the biosurfactant produced was a glycolipid. The GC-MS analysis confirmed the methyl and ethyl esters of fatty acids. The biosurfactant from the bacteria exhibited antibacterial activity against bacterial pathogens such as Pseudomonas aeruginosa (MTCC 2453), Escherichia coli (MTCC 1610), Salmonella paratyphi and Bacillus subtilis. The glycolipid biosurfactant had antibiofilm activity as evidenced in Staphylococcus aureus (MTCC 1430). All these results indicated the beneficial effect of the biosurfactant in plant-endophyte interactions. The properties exhibited by the biosurfactant suggest that it can be exploited commercially for the production of novel antibiotics.

Starch-PVA composite films with zinc-oxide nanoparticles and phytochemicals as intelligent pH sensing wraps for food packaging application.

The increasing acceptance of ready to eat food generates demand on development of active and intelligent food packaging material. Even though many polymers have been used for the packaging, they have limitations for broad applications. Among the various polymers, Poly Vinyl Alcohol is a promising film forming polymer with highly flexible, emulsifying and adhesive properties. A variety of nano-fabrication techniques have already been reported to improve the mechanical and antimicrobial properties of PVA to exploit its wider applications. In the present study, starch-PVA based composite films incorporated with zinc oxide nanoparticles and phytochemicals were prepared by solvent casting technique. The films were characterized by XRD, FT-IR, UV-Vis spectrometry and SEM. The developed nanocomposite films were demonstrated to have enhanced water barrier, mechanical and antimicrobial properties. The unique features of the nanocomposite with its pH indication property demonstrated in the study indicate its potential usage in food packaging applications.