Patent ID: 7754470

Claim:
A method for reduction of Chromium (Cr)(VI) to Chromium (Cr) (III) or Uranium (U)(VI) to Uranium (U)(IV), the method comprising: contacting said Chromium (Cr)(VI) or Uranium (U)(VI) with an effective amount of an E. Coil nitroreductase enzyme (ChrR) polypeptide, wherein said E. coli nitroreductase enzyme (ChrR) polypeptide comprises at least one amino acid alteration at amino acid residue 128, 150 or 154 relative to the wild-type enzyme set forth in SEQ ID NO:1, wherein said alteration has enhanced enzyme kinetics for reduction of Chromium (Cr)(VI) or Uranium (U)(VI) relative to the wild-type E. coli nitroreductase enzyme having the amino acid sequence of SEQ ID NO:1.