Unlocking nature's toolbox: Kinetin-producing Priestia flexa VL1 paves the way for efficient bioremediation of chromium-contaminated environments

Abstract

Elevated levels of hexavalent chromium (Cr(VI)) present a severe environmental threat, leading to soil and water contamination. Traditional reduction methods, including electrochemical, photocatalytic, and microwave catalytic processes, have proven effective but face challenges such as durability, pH sensitivity, temperature constraints, varying Cr(VI) concentrations, oxygen absorption issues, and high operational costs. In contrast, soil bacteria, provide a cost-efficient and impactful solution, offering sustainable outcomes without secondary pollution concerns. Bioremediation, focusing on the microbial reduction of Cr(VI) to Cr(III), emerges as an ecologically-friendly alternative, utilizing bacterial chromium reductase as an abundant and adaptable resource for Cr(VI) remediation. We isolated Priestia flexa VL1 (PFVL1) which reduces Cr(VI) concentrations up to 200 mg/l to Cr(III). Fourier transform infrared (FTIR) spectroscopy and gas chromatography-mass spectrometry (GCMS), revealed kinetin molecules within PFVL1. Distinct expression patterns were observed in the genes responsible for Cr(VI) reduction and kinetin biosynthesis in PFVL1, contingent upon varying dosages. This investigation emphasizes PFVL1's substantial role in advancing Cr(VI) bioremediation through kinetin biosynthesis, contributing to a safer and more sustainable environment.