Factors affecting chromium(VI) reduction by Thiobacillus ferrooxidans

The ability of Thiobacillus ferrooxidans cultures to reduce chromium(VI) to chromium(III) was evaluated under different conditions. In T ferrooxidans cultures with sulphur as energy source, the capacity for chromium(VI) reduc tion was related to the generation of sulphur compounds (sulphite, thiosulp hate and polythionates) with high reducing power. In contrast with other ch romium(VI)-reducing microorganisms, T.ferrooxidans showed higher chromium(V I) reduction at low pH. The reduction of chromiurn(VI) also increased with the age of the culture. A T.ferrooxidans cells were capable of growing unde r anaerobic conditions with chromiurn(VI) as the terminal-electron acceptor . (C) 2001 Elsevier Science B.V. All rights reserved.