Chromate reduction was carried out by resting cells of Achromobacter sp. Ch-1 with lactate as electron donor under aerobic conditions. The reduction activity of the samples supplemented with lactate was two times as those without lactate. The reduction rate was influenced by initial pH and lactate concentration. Under the optimal conditions, pH 9.0 and 4000 mg l(-1) lactate supplement, reduction rate was 5.45 mg l(-1) min(-1). The reduction rate decreased with increasing of Cr(Vl) concentrations and increased with cell densities proportionally. The maximum reduction limit of Ch-1 cells was obtained at 2107 mg l(-1) of Cr(VI). (C) 2007 Elsevier Ltd. All rights reserved.