Degradation of the radioactive and non-labelled branched 4(3′,5′-dimethyl 3′-heptyl)-phenol nonylphenol isomer by Sphingomonas TTNP3

The degradation of the 4( 3', 5'- dimethyl- 3'- heptyl)- phenol ( p353NP) nonylphenol isomer in cultures of Sphingomonas TTNP3 supplemented with the technical mixture of nonylphenol was first assessed. Then the radioactive and non- labelled form of these diastereomers were both synthesised. The radioactive isomers were synthesised using [ ring- U-C-14]- labelled phenol and 3,5- dimethyl- 3- heptanol by Friedel and Crafts alkylation. The time- course of degradation was performed with and without C-14- p353NP; balancing of radioactivity was calculated from different soluble fractions ( organic, aqueous), bacterial biomass, and (CO2)-C-14 evolved as mineralization product. The noticeable portion of C-14 bound to biomass showed that at least the aromatic ring of C-14- p353NP was degraded and served as energy source and probably as carbon source for bacterial growth. In addition, the appearance of 3,5dimethyl- 3- heptanol, the nonanol corresponding with the side- chain of p353NP, was demonstrated in the bacterial media, and its concentration determined during the course of fermentation. Besides the parent C-14- p353NP, no other radioactive compounds, i. e. metabolites of C-14- p353NP were detected in the media.