A central fission pathway in alkylphenol ethoxylate biodegradation.

A representative alkylphenol Triton X-100 (having 9.5 oxyethylene subunits) was treated over 40 days under the conditions of the continuous flow activated sludge simulation test in a plant with aeration and denitrification chambers. Treated sewage was separated by sequential extraction with ethyl acetate and chloroform. The extracts were analysed by high-performance liquid chromatography-electrospray ionisation-mass spectrometry (HPLC-ESI-MS). Single ion chromatograms of the chloroform extracts showed the presence of neutral, mono- and di-carboxylated poly(ethylene glycols). This is evidence of the central fission of alkylphenol ethoxylates (APE). Simultaneously, the APE having omega-carboxylated oxyethylene chains were identified. This is the evidence that apart from central fission, the omega-oxidation oxyethylene chain pathway also occurs.