Introduction

Chromium exists mainly in trivalent and hexavalent forms, of which hexavalent chromium has carcinogenic and mutagenic properties. Hexavalent chromium, widely used in industry, quickly enters soil and groundwater, and pollutes the environment. Using microorganisms is one of the safest and most effective alternatives for regenerating soil and groundwater contaminated with hexavalent chromium. Among them, the use of Generally Recognized as Safe (GRAS) strains and edible strains can be a safer alternative. We sought to isolate bacteria that remove hexavalent chromium from Korean fermented food as an alternative.

Goals

Isolate of bacteria capable of removing hexavalent chromium from fermented foodsIdentification of hexavalent chromium removal mechanism in isolated bacteria

Materials & Methods

A bacteria with chromium-reducing ability was newly isolated from doenjang, a traditional Korean fermented food. A comparative evaluation of the ability of several bacteria to hexavalent chromium removal was conducted, and resistance to various concentrations of hexavalent chromium was tested.

Results

The isolate strain was designated Bacillus sp. KICET-4. The reduction performance for hexavalent chromium of KICET-4, which evaluated several bacteria's characteristics, was observed. Although growth was inhibited at a hexavalent chromium concentration of 200 mg Cr/L, KICET-4 still played a role in removing hexavalent chromium. Also, when the medium containing hexavalent chromium was treated with KICET-4, it was confirmed that no cytotoxicity was observed compared to the untreated control group.

Summary

We isolated several bacteria capable of removing hexavalent chromium from Korean fermented foods. Among these, KICET-4 showed the most excellent hexavalent chromium removal ability. In addition, it was confirmed through cytotoxicity experiments that the high concentration of hexavalent chromium present in the medium was removed to a level below the toxic concentration. It is expected that KICET-4 can be applied as a sustainable purification technology to environments polluted with hexavalent chromium.

Key words: Hexavalent chromium, KICET-4, GRAS strains