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 (OPEO_n, or Triton® X-100; average n = 9.5) as a sole carbon source. It can grow on 0.05-20% of OPEO_n with a specific growth rate of 0.34-0.44 h^-1. High-performance liquid chromatography-mass spectrometer analysis of OPEO_n 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 (COPEO_n, n = 2, 3) and carboxyoctylphenol polyethoxycarboxylates (COPEC_n, n = 2, 3) began at the log stage, while octylphenol polyethoxycarboxylates (OPEC_n, n = 1-3) was formed at the stationary phase. All the short-ethoxylated metabolites, OPEO_n, OPEC_n, COPEO_n, and COPEC_n, accumulated when the cells were in the stationary phase. This study is the first to demonstrate the formation of COPEO_n and COPEC_n from OPEO_n by an aerobic bacterium.