Bacterial phosphonate degradation, phosphite oxidation and polyphosphate accumulation

Abstract

Large quantities of xenobiotic phosphonates (Pn), which are used as pesticides, detergent additives, antibiotics, and flame retardants, are released into the environment. These C-P compounds are generally resistant to chemical hydrolysis and recalcitrant to biodegradation. We have cloned the Klebsiella aerogenes phn gene cluster which is required for degrading Pn and also for oxidizing phosphite (Pt) to phosphate (Pi). Recombinant plasmids containing the phn gene cluster allowed E. coli MV1184 to grow with aminoethylphosphonate (AEPn), ethylphosphonate (EPn), methylphosphonate (MPn) and Pt as a sole source of phosphorus. Pi, which is generated by Pn breakdown and Pt oxidation, is also a priority target for controlling the eutrophication in natural bodies of water. We examined the genetic improvement of bacterial Pi accumulation by manipulating the genes involved in the key steps of Pi transport and polyphosphate (polyP) formation.