Reduction and precipitation of chromate by mixed culture sulphate- reducing bacterial biofilms

TY - JOUR

T1 - Reduction and precipitation of chromate by mixed culture sulphate- reducing bacterial biofilms

AU - Smith, W. L.

AU - Gadd, G. M.

N1 - Acknowledgements: W.L. Smith gratefully acknowledges receipt of a BBSRC postgraduate research studentship. We would also like to thank Martin Kierans for assistance with electron microscopy and EDXA analysis, and Margaret Gruber for photography.

PY - 2000/6

Y1 - 2000/6

N2 - The ability of sulphate-reducing bacterial biofilms to reduce hexavalent chromium (Cr(VI)) to insoluble Cr(III), a process of environmental and biotechnological significance, was investigated. The reduction of chromate to insoluble form has been quantified and the effects of chromate on the carbon source utilization and sulphate-reducing activity of the bacterial biofilms evaluated. Using lactate as the carbon/energy source and in the presence of sulphate, reduction of 500 μmol l-1 Cr(VI) was monitored over a 48-h period where 88% of the total chromium was removed from solution. Mass balance calculations showed that ca 80% of the total chromium was precipitated out of solution with the bacterial biofilm retaining less than 10% of the chromium. Only ca 12% of the chromate added was not reduced to insoluble form. Although Cr(VI) did not have a significant effect on C source utilization, sulphate reduction was severely inhibited by 500 μmol-1 Cr(VI) and only ca 10% of the sulphate reducing activity detected in control biofilms occurred in the presence of Cr(VI). Low levels of sulphide were also produced in the presence of chromate, with control biofilms producing over 10-times more sulphide than Cr(VI)-exposed biofilms. Sulphide- or other chemically-mediated Cr(VI) reduction was not detected. The biological mechanism of Cr(VI) reduction is likely to be similar to that found in other sulphate-reducing bacteria.

AB - The ability of sulphate-reducing bacterial biofilms to reduce hexavalent chromium (Cr(VI)) to insoluble Cr(III), a process of environmental and biotechnological significance, was investigated. The reduction of chromate to insoluble form has been quantified and the effects of chromate on the carbon source utilization and sulphate-reducing activity of the bacterial biofilms evaluated. Using lactate as the carbon/energy source and in the presence of sulphate, reduction of 500 μmol l-1 Cr(VI) was monitored over a 48-h period where 88% of the total chromium was removed from solution. Mass balance calculations showed that ca 80% of the total chromium was precipitated out of solution with the bacterial biofilm retaining less than 10% of the chromium. Only ca 12% of the chromate added was not reduced to insoluble form. Although Cr(VI) did not have a significant effect on C source utilization, sulphate reduction was severely inhibited by 500 μmol-1 Cr(VI) and only ca 10% of the sulphate reducing activity detected in control biofilms occurred in the presence of Cr(VI). Low levels of sulphide were also produced in the presence of chromate, with control biofilms producing over 10-times more sulphide than Cr(VI)-exposed biofilms. Sulphide- or other chemically-mediated Cr(VI) reduction was not detected. The biological mechanism of Cr(VI) reduction is likely to be similar to that found in other sulphate-reducing bacteria.

UR - https://www.scopus.com/pages/publications/0034099722

U2 - 10.1046/j.1365-2672.2000.01066.x

DO - 10.1046/j.1365-2672.2000.01066.x

M3 - Article

C2 - 10849174

AN - SCOPUS:0034099722

SN - 1364-5072

VL - 88

SP - 983

EP - 991

JO - Journal of Applied Microbiology

JF - Journal of Applied Microbiology

IS - 6

ER -