Effect of Surfactants on Microbial Metabolic Activity and Community Structure in Oil Field–Produced Water Systems

Surfactants are the commonly used technologies in oil field recovery processes due to their low cost and high efficiency. Frequent application leads to a significant accumulation of surfactants in the environment. However, the effect of surfactants on the environment and its mechanism are still unclear. TX-100 and HABS were selected as surfactants for the experiment to explore the effects of surfactants on microbial activity from cellular metabolic activity and mechanism of action. The results manifested that the growth of microorganisms in different surfactants had obvious law of low-concentration promotion, high-concentration inhibition. Higher amount of surfactant addition led to a significant reduction in biomass, protein content, polysaccharide content, and dehydrogenase activity. The analysis of community structure demonstrated that TX-100 and HABS increased the abundance and diversity of bacterial communities. Specifically, the relative abundance of Enterobacter increased, while Pseudomonas decreased slightly. In addition, the two surfactants could interfere with the normal physiological functions of the cells by disrupting the growth cycle of the bacteria and destroying the cell membrane structure, thus reducing their activities or even causing their death. TX-100 and HABS are explored as representatives, providing references for the widespread application of surfactants in the environment in the future. In addition, it proposes a set of toxicological analysis methods for the chemicals used in oil fields, serving as a basis for future environmental impact assessments.