The Microbial Degradation of Natural and Anthropogenic Phosphonates

Abstract

Phosphonates are compounds containing a direct carbon–phosphorus (C–P) bond, which is particularly resistant to chemical and enzymatic degradation. They are environmentally ubiquitous: some of them are produced by microorganisms and invertebrates, whereas others derive from anthropogenic activities. Because of their chemical stability and potential toxicity, man-made phosphonates pose pollution problems, and many studies have tried to identify biocompatible systems for their elimination. On the other hand, phosphonates are a resource for microorganisms living in environments where the availability of phosphate is limited; thus, bacteria in particular have evolved systems to uptake and catabolize phosphonates. Such systems can be either selective for a narrow subset of compounds or show a broader specificity. The role, distribution, and evolution of microbial genes and enzymes dedicated to phosphonate degradation, as well as their regulation, have been the subjects of substantial studies. At least three enzyme systems have been identified so far, schematically distinguished based on the mechanism by which the C–P bond is ultimately cleaved—i.e., through either a hydrolytic, radical, or oxidative reaction. This review summarizes our current understanding of the molecular systems and pathways that serve to catabolize phosphonates, as well as the regulatory mechanisms that govern their activity.

Supramolecular Binding of Phosphonate Dianions by Nanojars and Nanojar Clamshells

“…They can also be viewed as derivatives of deprotonated phosphonic (phosphorous) acid, HPO 3 2– , although the oxidation state of the phosphorus atom in the latter is 3+ as opposed to 5+ in phosphonates and phosphates. Phosphonates are encountered in nature and are involved in physiological processes, the global phosphorus cycle and the biogeochemical generation of methane. , A large variety of industrial, agricultural and household activities also employ phosphonates, in applications including pesticides (e.g., glyphosate), plant growth regulators, detergents, bleach stabilizers, water softening and desalination agents, corrosion inhibitors, antiscalants, concrete retarders, metal extracting agents, as well as inhibitors of enzymes that utilize phosphate or pyrophosphate as a substrate (treatment of osteoporosis, antibiotic and antiviral medications). − Phosphonates are also actively studied for different novel applications, such as porous materials for gas storage and catalysis, magnetic and luminescent materials, proton conduction, and prodrugs. − Phosphonate esters, such as dimethyl methylphosphonate, are used as flame retardants among various other applications…”