Tributyl phosphate degradation by immobilized cells of a Citrobacter sp.
Owen S., Jeong BC., Poole PS., Macaskie LE.
Tributyl phosphate (TBP), a plasticizer and solvent, is used in nuclear fuel reprocessing, generating TBP wastes laden with residual uranium. A Citrobacter sp. accumulated heavy metals via a phosphohydrolase(s) that precipitated metals with inorganic phosphate liberated from an organic phosphate "donor" molecule (TBP). Mutant analysis suggested that TBP hydrolysis was not attributable to a previously documented acid phosphatase (monoesterase). Purified monoesterase had little activity against phospho di- and triesters, had no requirement for Mg 2+ or Mn 2+ , and was EDTA-resistant. Conversely, TBP cleavage by immobilized cells was enhanced by Mg 2+ , and ininhibited by Mn 2+ and EDTA. A separate phosphotri/diesterase was implicated. © 1992 Humana Press Inc.