“…that reduce Cr(VI) are P. ambigua C-13 and P.¯uorescens LB300, the latter aerobically and anaerobically (Bopp and Ehrlich, 1988). Among enterobacterial strains, Enterobacter aerogenes EAO reduced Cr(VI) in rich medium, with chromate reductase activity induced by nitrite (Clark, 1994), whereas E. cloacae HO1 reduced up to 2 mM CrO 4 2) to Cr(III), which was precipitated in the culture medium as Cr(OH) 3 anaerobically (Komori et al, 1990) at pH 7.0 to 7.8 (De Mel et al, 1994). In contrast, Escherichia coli ATCC 33456 reduced Cr(VI) aerobically and anaerobically within 12 h (Shen and Wang, 1993), but the product of the reaction [probably Cr(III)] was almost completely (98%) retained in a soluble form in the culture supernatant (Shen and Wang, 1993).…”