BACTERIAL PHOSPHONATE DEGRADATION, PHOSPHITE OXIDATION AND POLYPHOSPHATE ACCUMULATION

Large quantities of xenobiotic phosphonates (P-n), which are used as p esticides, detergent additives, antibiotics, and flame retardants, are released into the environment. These C-P compounds are generally resi stant to chemical hydrolysis and recalcitrant to biodegradation. We ha ve cloned the Klebsiella aerogenes phn gene cluster which is required for degrading P-n and also for oxidizing phosphite (P-t) to phosphate (P-i). Recombinant plasmids containing the phn gene cluster allowed E. coli MV1184 to grow with aminoethylphosphonate (AEP(n)), ethylphospho nate (EP(n)), methylphosphonate (MP(n)) and P-t as a sole source of ph osphorus. P-i, which is generated by P-n breakdown and P-t oxidation, is also a priority target for controlling the eutrophication in natura l bodies of water. We examined the genetic improvement of bacterial P- i accumulation by manipulating the genes involved in the key steps of P-i transport and polyphosphate (polyP) formation. Copyright (C) 1996 Elsevier Science B.V.