The multidrug-resistant strains of food spoilage bacteria and foodborne pathogenic bacteria in food are badly in need of being controlled by effective bio-preservatives. In this study, the XN8 strain was isolated from Jiangshui and identified as Lactobacillus coryniformis according to 16S rRNA gene sequence. One of the bacteriocins produced by XN8 was purified by ammonium sulfate precipitation and a series of chromatographic column, and designated as lactocin XN8-A (LXA). The molecular mass of LXA was 3100.0242 Da by MALDI-TOF MS. The LXA showed good heat, pH and storage stabilities. However, it was sensitive to proteases. The LXA was found to have a broad antimicrobial spectrum on both Gram-positive and Gram-negative bacteria including multidrug-resistant strains and Listeria monocytogenes. Its minimum inhibitory concentration (MIC) for both E. coli and S. aureus was 6.85 μg/mL. The LXA had a bactericidal mode without cell lysis by the growth curve and time-kill assay. The results of electron microscope showed that the LXA destroyed membrane permeability and induced pore-formation of target cells. Furthermore, the LXA induced cell cycle arrest at both G1 and G2/M phase by cell cycle analysis. This research suggests that the LXA has promising potential as bio-preservative in food industry.

Novel zirconium and silver co-doped TiO2 nanoparticles were fabricated and utilized as effective multifunctional visible light photocatalysts for inactivation of bacteria (E. coli) as well as degradation of azo dye (Direct Red-22) for the first time.

No abstract

Perfluorinated chemicals have attracted worldwide concern owing to their wide occurrence and resistance to most conventional treatment processes. In this work, a novel photocatalyst was fabricated by modifying TiO 2 nanotube arrays with molecularly imprinted polymers. The molecularly imprinted polymer-modified TiO 2 nanotubes (MIP-TiO 2 NTs) were characterized and tested for the selective removal of perfluorooctanoic acid (PFOA) from water. The amount of PFOA adsorbed by the MIP-TiO 2 NTs was as high as 0.8125 g/cm 2 . PFOA decomposition and defluorination by the MIP-TiO 2 NTs reached 84% and 30.2% after 8 h reaction, respectively. The Freundlich model and pseudo-first-order kinetics were used to describe the observed adsorption and decomposition of PFOA, respectively. Compared with TiO 2 NTs and nonmolecularly imprinted polymer-modified TiO 2 NTs, the MIP-TiO 2 NTs exhibited not only a higher PFOA degradation rate but also enhanced selectivity for target chemicals. The MIP-TiO 2 NTs could also selectively and rapidly remove PFOA from secondary effluent, exhibiting a decomposition of 81.1%, almost as high as that observed in pure water. Investigation of the effects of scavengers on the photocatalytic reaction indicated that photogenerated holes were the main oxidant for PFOA decomposition, and the PFOA degradation mechanism and pathway were proposed.