Recognition of a New Cr(VI)-Reducing Strain and Study of the Potential Capacity for Reduction of Cr(VI) of the Strain

Abstract

The biotransformation of hexavalent chromium [Cr(VI)] via Cr(VI)-reducing microorganisms is considered an ecofriendly approach to detoxify Cr(VI). A new Cr(VI)-reducing bacterium named Microbacterium sp. QH-2 was isolated in this study. Scanning electron microscopy (SEM) images showed protrusions on the bacterial surface of strain QH-2 after an 18 h incubation in media under 10 mM Cr(VI) treatment. Results of the experiments on the capacity of reducing Cr(VI) indicated that strain QH-2 could reduce 100% Cr(VI) less than 48-96 h. When media with 4 mM Cr(VI) were incubated, the fastest reduction rate of strain QH-2 could come up to 2.17 mg/L Cr(VI) h−1. Furthermore, strain QH-2 could reduce Cr(VI) over the pH between 7 and 10. The optimum pH to reduce Cr(VI) by strain QH-2 was 9. Strain QH-2 also exhibited a relatively high tolerance even to 20 mM Cr(VI). These results declared that strain QH-2 had the potential to detoxify Cr(VI) in the Cr(VI)-contaminated soil or effluent.

Efficient, fast, simple, and eco-friendly methods for separation of toxic chromium(VI) ions based on ion exchangers and polymer materials impregnated with Cyphos IL 101, Cyphos IL 104, or D2EHPA

“…Chromium is a transition metal present in the environment, both as a result of natural processes (e.g., erosion of rocks leading to the release of chromium as a result of chromite oxidation) as well as human activity related to the development of various industrial branches (e.g., productions of steel, paints and textile dyes, ceramic glazes, and refractory bricks) (Tumolo et al 2020 ; Hausladen et al 2018 ; Zhang et al 2022 ). The systematic increase in the use of chromium associated with anthropogenic activity, observed for several decades, makes the pollution of waters, soils, or plant crops by this element a serious problem (Oliveira 2012 ; Wang and Cui 2019 ; Gezahegn et al 2021 ). However, the influence of chromium on living organisms depends on its oxidation state, the most stable and widespread forms existing in aqueous solutions are Cr(III) and Cr(VI), which is considered to be particularly dangerous (Sharma et al 2022 ; Han et al 2023 ).…”

Artificial Neural Networks (ANNs) and Response Surface Methodology (RSM) Approach for Modelling the Optimization of Chromium (VI) Reduction by Newly IsolatedAcinetobacter radioresistensStrain NS-MIE from Agricultural Soil

“…Numerous technologies and approaches have been studied and developed in the past to remove hexavalent chromium such as ion exchange, chemical precipitation, adsorption, and biosorption, electrodialysis, and reverse osmosis [8, 9]. These technologies have been practiced for decades due to their efficacy.…”