Phosphite Production by Streptomyces viridochromogenes

The industrial production of phosphochemicals is highly energy-intensive, involving the reduction of the phosphate mineral apatite to white phosphorus, a toxic and reactive intermediate with significant environmental risk. Phosphite, an activated form of phosphorus, is a potential alternative substrate for phosphochemical synthesis, yet direct reduction of phosphate to phosphite remains challenging. While environmental and microbial studies have suggested biochemical pathways for reducing phosphate to phosphite, these pathways have not been conclusively demonstrated in axenic culture. In this study, we characterize phosphite production by Streptomyces viridochromogenes and demonstrate that phosphite is an abiological product of phosphonoformyl-CMP decomposition, an intermediate in the biosynthesis of the herbicide phosphinothricin. The phosphonoformyl-CMP intermediate yields an "activated" phosphonoformate for decarboxylation, producing phosphite at biological temperatures and pH following phosphoanhydride hydrolysis. Using S. viridochromogenes spent media, we demonstrate a hybrid biotic-abiotic synthesis of the metal chelator aminotris(methylenephosphonate), illustrating a potential synthetic route to phosphochemicals from biogenic phosphite.