Phosphonate utilization by bacterial cultures and enrichments from environmental samples

Abstract

A selection of axenic microbial strains and a variety of environmental samples were investigated with respect to the utilization of a series of natural and xenobiotic phosphonates as the sole phosphorus source for growth. Phosphonate degradation was observed only with bacteria and not with eucaryotic microorganisms. All representatives of the phosphonates examined supported bacterial growth, with the exception of methylphosphonate diethylester. Yet, distinctly different phosphonate utilization patterns were noted between phosphonate-positive strains. C-P bond cleavage by a photosynthetic bacterium is reported for the first time; growing photoheterotrophically, Rhodobacter capsulatus ATCC 23782 was able to utilize 2-aminoethylphosphonate and alkylphosphonates. Bacteria with the potential to utilize at least one of the phosphonate moieties from the xenobiotic phosphonates Dequest 2010, Dequest 2041, and Dequest 2060 were detected in all environments, with only two exceptions for Dequest 2010. Phosphonate P utilization to an extent of 94 and 97%, for Dequest 2010 and Dequest 2041, respectively, provided evidence that a complete breakdown of these compounds with respect to the C-P bond cleavage can be achieved by some bacteria. The results suggest that phosphonateutilizing bacteria are ubiquitous, and that selected strains can degrade phosphonates that are more complex than those described previously.

Identification of cognate ligands for the Escherichia coli phnD protein product and engineering of a reagentless fluorescent biosensor for phosphonates

“…The protein also binds other biologically available phosphoruscontaining compounds such as phosphonoacetate (K d ¼ 0.9 mM) and phosphate (K d ¼ 50 mM) (Table 4). Furthermore, the conjugate responds to phenylphosphonate or glyphosate (Table 4), which are synthetic phosphonates that are not metabolized by E. coli (Schowanek and Verstraete 1990). In addition to alkylphosphonates, PhnD4-acrylodan was tested for binding the nerve agent degradation products ethylmethylphosphonic acid (EMPA), isopropylmethylphosphonic acid (IMPA), and pinacolylmethyl phosphonic acid (PMPA).…”

“…The most common natural phosphonate is 2-aminoethylphosphonate (2-AEP), a precursor in the biosynthesis of phosphonolipids (Baer and Stanacey 1964), phosphonoproteins (Kittredge and Roberts 1969), and phosphonoglycans (Korn et al 1973). While only few strains of bacteria are able to synthesize phosphonates (Hendlin et al 1969), numerous Gram-negative species can scavenge carbon-phosphorus containing compounds as a source of phosphorus (Wackett et al 1987;Schowanek and Verstraete 1990;Dick and Quinn 1995). The Escherichia coli 12.6-kb phn operon (previously known as the psiD locus) codes for 17 genes involved in binding, uptake, and metabolism of phosphonates, and is induced at low phosphate concentrations (Metcalf et al 1990;Metcalf and Wanner 1991).…”

Microbial metabolism of sulfurand phosphorus-containing xenobiotics

“…Despite the relative rarity of the C-P bond in nature, the ability to degrade glyphosate as a sole source of phosphorus for growth appears to be common in the environment [33]. Although their natural role is unknown, the enzymes of glyphosate metabolism were presumably present in the environment before the herbicide came on the market in 1971, since a strain of Arthrobacter atrocyaneus which was deposited in a culture collection prior to the introduction of the herbicide can also metabolize the compound [30].…”

A comparison of three bacterial phosphonoacetate hydrolases from different environmental sources

“…Organophosphonates, therefore, mostly fail to serve as sources of carbon (and nitrogen) for microbial growth; phosphate released during catabolism of the carbon skeleton represses and/or inhibits further mineralization (Wackett et al 1987;Wanner 1993). Environments such as sewage sludges, fresh water and marine sediments, and agricultural soils that act as organophosphonate sinks, are rarely deficient in inorganic phosphate, making organophosphonate recalcitrance a poss-ible ecological problem (Schowanek and Verstraete 1990); evidence for the environmental accumulation of anthropogenic organophosphonates has been presented (Verweij et al 1979(Verweij et al , 1982. described the isolation of the Gram-negative bacterium, Pseudomonas fluorescens 23F, capable of utilizing the synthetic organophosphonate phosphonoacetate as a carbon and phosphorus source.…”