BIODEGRADATION AND TRANSFORMATION OF 4,4'-DIHALODIPHENYL AND 2,4-DIHALODIPHENYL ETHERS BY SPHINGOMONAS SP STRAIN SS33

The bacterium Sphingomonas sp. strain SS33, obtained from parent diphe nyl ether-mineralizing strain SS3 (S. Schmidt, R.-M. Wittich, D. Erdma nn, H. Wilkes, W. Francke, and P. Fortnagel, Appl. Environ. Microbiol. 58:2744-2750, 1992) after several weeks of adaptation on 4,4'-difluor odiphenyl ether as the new target compound, also utilized 4,4'-dichlor odiphenyl ether for growth. Intermediary halocatechols were also miner alized via the ortho pathway by type I enzymes. 4,4'-Dibromodiphenyl e ther was not used as a carbon source although transformation by restin g cells yielded mononuclear haloaromatic compounds, such as 4-bromophe nol and 4-bromocatechol. The same was true for the conversion of 2,4-d ichlorodiphenyl ether, which yielded the respective (halo-) phenols an d (halo-) catechols.