Jun KAMITO

Microbial Degradation of Tris (1,3-dichloro-2-propyl) phosphate, a Persistent Organophosphorous Compound

Ryo-hei YAMADA, Yoshio KERA, Shouji TAKAHASHI

Tris (1,3-dichloro-2-propyl) phosphate (TDCPP), a typical chlorinated organophosphate triesters, have been used worldwide as flame-retardants and plasticizers. Because this molecule is known to possess carcinogenicity, mutagenicity and neurotoxicity, there have been concerns about residues of TDCPP in natural environment. Recently, we succeed in obtaining mixed cultures, designated No. 45D, capable of degrading TDCPP.
No. 45D showed a TDCPP degradation and chloride ion release in the medium containing TDCPP as a sole phosphorous source. Even in the presence of good phosphorous source, NaH2PO4, No. 45D was able to degrade TDCPP, and chloride ion release was significantly increased. No. 45D also showed chloride ion release from 1,3-dichloro-2-propanol (1,3-DCP), a putative metabolite of TDCPP, suggesting that No. 45D produced 1,3-DCP as a metabolite of TDCPP. The cell growth of No. 45D was significantly inhibited by the addition of kanamycin, but by cycloheximide. Denaturing gradient gel electrophoresis (DGGE) pattern of No. 45D showed multiple bands, indicating that various microorganisms exist in the mixed culture. DGGE profile also showed that bacterial population structure in No. 45D changed with cultivation time and was also changed by the presence of NaH2PO4.