Isolation and Identification of Chromium-Reducing Bacteria from Challawa Industrial Area Kano State, Nigeria

Abstract

Chromium (Cr) is toxic, mutagenic, carcinogenic, and harmful to most plants, animals, and bacteria inhabiting aquatic environments because it is motile, highly toxic, soluble in water and it is a good oxidizing agent and it is detrimental to cell membranes. Chromium remediation with the help of microorganisms is believed to be the best and cheaper technology at hand to clean up Cr contamination, some chromium resistant bacteria can reduce chromium (VI) to (III) with the help of reductase enzymes. This research was aimed to isolate and identify bacteria capable of reducing chromium from tannery effluent. The level of chromium from different tannery industries was analyzed using Microwave Plasma Atomic Absorption Spectroscopy (MPAES) and compared to Environmental Protection Agency (EPA) standard which shows that all the samples were above the EPA standard except for one sample, a pour plating method was used to isolate the bacteria on Luria Bertani (LB) amended with K2Cr2O7 after serial dilution, the isolate was identified morphologically, biochemically and molecularly as Acetanaerobacter sp. based on 16s rRNA gene sequencing and molecular phylogenetic analysis, Atomic absorption spectrophotometry was carried out to determine the level of chromium from the bio-reduced sample. A reduction of 18.32% was observed in broth treated with the isolate within 48 hours of incubation at 37°C.