Growth of Pseudomonas sp. TX1 on a wide range of octylphenol polyethoxylate concentrations and the formation of dicarboxylated metabolites

Pseudomonas sp. TX1, is able to use octylphenol polyethoxylates (OPEOn, or Triton® X-100; average n = 9.5) as a sole carbon source. It can grow on 0.05–20% of OPEOn with a specific growth rate of 0.34–0.44 h−1. High-performance liquid chromatography–mass spectrometer analysis of OPEOn degraded metabolites revealed that strain TX1 was able to shorten the ethoxylate chain and produce octylphenol (OP). Furthermore, formation of the short carboxylate metabolites, such as carboxyoctylphenol polyethoxylates (COPEOn, n = 2, 3) and carboxyoctylphenol polyethoxycarboxylates (COPECn, n = 2, 3) began at the log stage, while octylphenol polyethoxycarboxylates (OPECn, n = 1–3) was formed at the stationary phase. All the short-ethoxylated metabolites, OPEOn, OPECn, COPEOn, and COPECn, accumulated when the cells were in the stationary phase. This study is the first to demonstrate the formation of COPEOn and COPECn from OPEOn by an aerobic bacterium.