Enzymatic Reduction of Hexavalent Chromium by Hexavalent Chromium Tolerant Pseudomonas ambigua G-1

Abstract

When hexavalent chromium (Cr6+) tolerant Pseudomonas ambigua G-l was cultivated in nutrient broth containing 150 ppm Cr6+, the Cr6+ content of the broth rapidly decreased. The Cr6+ reducing enzyme found in a cell-free extract of P. ambigua G-l required NADH but not NADPH as a hydrogen donor for the reduction of Cr6+. The specific activities of cell-free extracts of several Cr6+ sensitive mutants derived from P. ambigua G-l showed decreases to one fourth to one tenth of that of P. ambigua G-l. Glucose protected the Cr6+ reducing enzyme against inactivation on dialysis. © 1987, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.