The objective of the present study is to describe a novel electro-peroxone (E-peroxone) process as a combination of two different systems for hydroxyl radical generation-ozonation and electrolysis-and to highlight its advantages for water and wastewater treatment compared to each system alone. An extensive review on the mechanism of the production of hydroxyl radical and in-situ generation of hydrogen peroxide, and the kinetics and efficiency of E-peroxone has been performed to evaluate the degradation and mineralization of different kinds of pollutants in aqueous media. The effects of experimental parameters such as ozone dose, applied current, solution of pH, anode type, and cathode selection on the efficiency of E-peroxone are discussed.
Inorganic phosphate is stored as a polyphosphate (polyP) polymer inside every living cell. This polymer is synthesized by the polyP kinase (PPK) enzyme using the terminal phosphate of ATP as substrate and it performs important functions in the cell. In this study, effects of high levels of PPK on Bacillus thuringiensis subsp. israelensis were analyzed. Recombinant Bti ppk, a PPK overproducer, was found to uptake more phosphate into the cell and produce a consistently higher amount of endotoxin than the wild type under culture conditions including a range of temperatures (25 °C, 30 °C, and 37 °C), pH values (pH 5, 6, 8, and 9), and carbon sources (maltose, mannitol, sucrose, and starch). Moreover, this strain was found to overexpress sigB, which might cause a significant increase in the acid tolerance of this microorganism. Spores of Bti ppk were found to be smaller compared to wild-type spores; however, bioassay experiments with third-instar wild Culex pipiens larvae proved that high toxicity is not the result of small spore size. This hypertoxic recombinant Bti strain is very useful for industrial applications, not only because it produces more endotoxin than the wild type under different culture conditions, but also because it is more acid-tolerant under the conditions tested.
There are different studies that aim to enhance the production of nisin by Lactococcus lactis since its chemical synthesis is not possible. In this study, glutathione (GSH) and pyruvate, which are known to reduce the oxidative stress of cells, have been shown to trigger the production of nisin at both transcriptional and translational levels in L. lactis cells grown under aerobic condition. Presence of GSH and pyruvate caused more nisin yield than the heme-supplemented medium. Moreover, the expression of genes that encode stress-related enzymes were apparently upregulated in the presence of GSH and pyruvate. It can be concluded that GSH and pyruvate contribute to the defense system of L. lactis cells and so that higher biomass was obtained which in turn enhance nisin production. Antioxidant effect of GSH and pyruvate was known; however, their stimulating effect on nisin production was shown for the first time in this study.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.