Diversity of octylphenol polyethoxylate-degrading bacteria: With a special reference to Brevibacterium sp. TX4

•Seven genera had not been previously reported to use OPEOn as the sole carbon source.•Frequent spray of pesticides could increase the diversity of OPEOn-degrading bacteria.•Brevibacterium sp. TX4 is the first Gram-positive bacterium reported to degrade OPEOn.•Brevibacterium sp. TX4 was demonstrated to shorten the ethoxylate chain of OPEOn.

Octylphenol polyethoxylates (OPEOn) are surfactants and prone to degradation into xenoestrogenic metabolites, polluting various environments. We sought to identify bacterial strains and potential metabolic pathways involved in OPEOn degradation. By enrichment culture, a greater diversity of bacterial strains was noted in a green house of pesticide factory, which had frequently sprayed by different formulated pesticides, compared to a rice field and a drainage ditch (32:6:5). These bacteria grew on OPEOn as the sole carbon source; seven genera had not been previously reported, of which only Brevibacterium was Gram-positive. Metabolic analysis by HPLC/MS revealed that Brevibacterium sp. TX4 could shorten the ethoxylate chain thereby degrading OPEOn, during which O2 was required. Hence, with frequent spray of pesticides formulated with anionic surfactants such as OPEOn could increase the diversity of OPEOn-degrading bacteria. Brevibacterium sp. TX4 is the first Gram-positive bacterium which was demonstrated to shorten the ethoxylate chain of OPEOn.