Nonylphenol Polyoxyethylene Ether

Nonylphenol polyoxyethylene ether (NP-40) has been shown to exert highly variable, concentration-dependent impacts on the activity of enzymes and the community composition of soil microbes. Specifically, catalase activity increased by 69% at 1,500 mg per kg, but decreased at higher concentrations, whereas activity of dehydrogenase steadily increased with treatment level up to 12,000 mg per kg. Potential nitrification activity increased at 1,500 mg kg per kg and decreased at higher concentrations. Content of microbial protein decreased-increased-decreased with increasing NP-40 concentration, peaking at 3,000 mg per kg. Levels of polysaccharides displayed a triphasic response to NP-40 application as well.
Analysis via high-throughput sequencing showed that NP-40 caused a reduction in bacterial richness and led to an increase in abundance of Arthrobacter, Bacillus, and Sphingomonas. Genera whose abundances were decreased by NP-40 included Actinoplanes, Phycicoccus, and Marmoricola. Scanning and transmission electron microscopy images of Escherichia coli revealed surface depression and aggregation of intracellular content after exposure to NP-40 suggesting degradation of the cell membrane and inhibition of metabolism.

Fig. 1 OTU distribution Venn diagram for all tested agents, including NP-40. (Yu L.; et al. 2025)