Degradation of organophosphorus wastes. Part II. Degradation of O,O-dimethyl phosphorodithioate by Thiobacillus thioparus TK-1 and pseudomonas AK-2.

O, O-Dimethyl phosphorodithioate (DMDTP) is an initial breakdown product of organophosphorus pesticides in fields. DMDTP is also released to natural environments by pesticide manufacturers. DMDTP-degrading microorganisms were not known. We isolated two bacteria from activated sludge. One of them, strain TK-1 identified as Thiobacillus thioparus, utilized DMDTP as a sole energy source and produced dimethyl phosphate (DMP) and sulfate. The other, strain AK-2 identified as Pseudomonas sp., utilized DMP as a sole energy and carbon source and degraded DMP to inorganic orthophosphate (Pi). DMDTP was degraded to Pi by the coaction of the two bacteria.