Evaluation of Cr(VI) reduction mechanism and removal by Cellulosimicrobium funkei strain AR8, a novel haloalkaliphilic bacterium.

The present study, a novel haloalkaliphilic Cr(VI) tolerant bacterial strain, Cellulosimicrobium funkei AR8, was isolated and characterized for its high Cr(VI) reduction. In batch experiments, Cr(VI) reduction was evaluated under different parametric conditions which include different pH (5-9), temperature (25-45°C), NaCl (0-3%) and Cr(VI) concentrations (100-250µg/ml). Variations in the cell surface functional groups and morphology of the bacterial cells after Cr(VI) reduction were characterized by FT-IR and SEM-EDX. FT-IR analysis revealed that cell surface functional groups such as alkanes, amide and amines are involved in chromium biosorption and SEM-EDX results showed that biosorption and immobilization of chromium species on the cell surface. Bioconversion of Cr(VI) into Cr(III) by strain AR8 was confirmed by XRD and Raman spectroscopy analysis. Intracellular localization of reduced product (Cr(III)) was visualized by TEM analysis. Various instrumentation analysis verified that Cr(VI) removal mechanism of C. funkei AR8 strain was achieved by both extra and intracellular reducing machinery. Toxicity study revealed that the bacterially reduced product exerted less toxic effects on phenotypic, survival (91.31%), hatching (84.04%) and heart function (115±1.03 beats/min) of zebrafish (Danio rerio) embryos. Higher Cr(VI) reducing ability of the strain under haloalkaliphilic condition suggests the C. funkei AR8 as a novel and efficient strain for remediating Cr(VI) contaminated industrial effluents with high salinity and alkalinity.

An overview of food waste management in developing countries: Current status and future perspective.

Food waste (FW) related issues in developing countries is currently considered to be a major threatening factor for sustainable development and FW management systems. Due to incomplete FW management systems, many developing countries are facing challenges, such as environmental and sanitary problems that are caused by FW. The difference in FW generation trends between developing countries and developed countries was reviewed in this work, which demonstrated that the effects of income level, population growth, and public participation in FW management are very important. Thus, this work aimed to provide an overview of recycling activities, related regulations, and current FW treatment technology in developing countries by following some case studies. Taiwan, has been suggested as being a successful case in terms of FW management, and is therefore a typical model for developing countries to follow. Finally, an integrative management system as a suitable model for FW management has been suggested for developing countries.