Bisphenol A Decelerates Sulfur Metabolism in <i>Roseovarius nubinhibens</i> at Environmentally Relevant Concentrations

Bisphenol A (BPA) is a pervasive environmental contaminant known for its detrimental effects on human health. However, its impact on multiple generations of microorganisms and the biogeochemical cycles they mediate, particularly at environmentally relevant concentrations, remains poorly understood. This study explores the effects of BPA on Roseovarius nubinhibens, a crucial bacterium in the global sulfur cycle, under both short-term (F0 generation) exposure at the observed-effect concentration (26 mg/L) and long-term (F20 generation) exposure at an environmentally relevant concentration (0.06 mg/L). Short-term exposure to the observed-effect concentration significantly inhibited bacterial growth by 12.9%, while long-term exposure at the environmentally relevant concentration induced notable morphological changes without affecting growth. BPA at the observed-effect concentration also disrupted extracellular polymeric substance (EPS) production and protein structures, particularly in the soluble-EPS (S-EPS) fraction, leading to impaired bacterial flocculation. Additionally, BPA at both exposure levels decelerated the conversion of dimethylsulfoniopropionate (DMSP), with the observed-effect concentration particularly affecting the cleavage pathway, reducing dimethyl sulfide (DMS) production. This study provides the first direct experimental evidence that BPA disrupts the metabolic equilibrium of sulfur cycling. These findings underscore the need for deeper exploration of BPA’s environmental risks, especially at environmentally relevant concentrations, and its potential to interfere with microbial-driven sulfur biogeochemistry.