Bisphenol A removal with nitrification and denitrification: Occurrence, mechanism, and microbial mutualism Xuekang Cao, Chao Liu, Xuemeng Zhang, Haining Huang, Xinyun Fan, Chuang Chen, Xu Duan, Yinguang Chen Critical Reviews in Environmental Science and Technology, 2025 Bisphenol A (BPA) is an emerging contaminant that disrupts endocrine systems and poses significant risks to organisms. It is increasingly detected in municipal wastewater due to its widespread use and high production volume. Despite this, gaps remain in understanding the sources of BPA in municipal wastewater, its effects on nitrification and denitrification, and the potential for its co-removal with ammonia or nitrate during biological nitrogen removal processes. This review first examines the sources of BPA, primarily from industrial effluents and landfill leachates, which enter wastewater treatment plants alongside domestic sewage. Additionally, it meticulously elucidated the influences, co-removal with nitrogen performance, and biotransformation mechanisms of BPA during nitrification and denitrification processes, shedding light on biotransformation pathways, functional microbes and key enzymes. While there is no consensus on BPA removal in anoxic conditions, aerobic environments support its biodegradation through various microorganisms. Lastly, the potential for microbial cooperation to enhance BPA and nitrogen co-removal is discussed, focusing on bacterial mutual alliances and bacteria-algae metabolic interaction consortiums. This review provides valuable guidance for the synergistic removal of BPA and nitrogen in wastewater treatment processes.
Denitrification research based on green electron supply and cell metabolism regulation LIU Chao, FAN Xinyun, ZHANG Xuemeng, CHEN Chuang, ZHU Mengru, et al. Energy Environmental Protection, 2024 As a key link in the nitrogen cycle, microbial denitrification plays an important role in removing nitrate pollution from the water environment, realizing the return of nitrogen to the atmosphere, and maintaining nitrogen balance. Heterotrophic denitrification is the mainstream process of biological nitrogen removal at present. In the process of treating wastewater with a low carbon-to-nitrogen ratio, chemical carbon sources such as acetic acid are often added to obtain enough electron donors to achieve efficient nitrate removal. In recent years, researchers have focused on the development of novel electron donors such as photoelectrons, short-chain gaseous alkanes, and metabolism regulation methods to promote the utilization of electron donors. Firstly, the types of photosensitizers, the dominant functional microorganisms, the photosensitizer-microbe complex in the process of photoelectron-driven denitrification, and the application status of phototrophic denitrification are systematically reviewed. Then, the microbial metabolic pathway of denitrification using methane, propane, and other short-chain alkanes as carbon sources is described, the performance of kitchen waste and other organic wastes as carbon source is introduced, and the formation mechanism and utilization characteristics of microbial carbon sources are also analyzed. Finally, the mechanisms of promoting denitrification by improving electron utilization efficiency of microorganisms are discussed, in order to expand the understanding of efficient biological nitrogen removal mechanisms. The future exploration direction, such as the efficient supply of green electrons and the regulation of intracellular electron distribution, are proposed, aiming to provide reference for the development of biological denitrification technology.
Metabolite Cross-Feeding Promoting NADH Production and Electron Transfer during Efficient SMX Biodegradation by a Denitrifier and S. oneidensis MR-1 in the Presence of Nitrate Chunxia Zhao, Xu Duan, Chao Liu, Haining Huang, Meirou Wu, Xuemeng Zhang, Yinguang Chen Environmental Science and Technology, 2023 Antibiotics often coexist with other pollutants (e.g., nitrate) in an aquatic environment, and their simultaneous biological removal has attracted widespread interest. We have found that sulfamethoxazole (SMX) and nitrate can be efficiently removed by the coculture of a model denitrifier (Paracoccus denitrificans, Pd) and Shewanella oneidensis MR-1 (So), and SMX degradation is affected by NADH production and electron transfer. In this paper, the mechanism of a coculture promoting NADH production and electron transfer was investigated by proteomic analysis and intermediate experiments. The results showed that glutamine and lactate produced by Pd were captured by So to synthesize thiamine and heme, and the released thiamine was taken up by Pd as a cofactor of pyruvate and ketoglutarate dehydrogenase, which were related to NADH generation. Additionally, Pd acquired heme, which facilitated electron transfer as heme, was the important composition of complex III and cytochrome c and the iron source of iron sulfur clusters, the key component of complex I in the electron transfer chain. Further investigation revealed that lactate and glutamine generated by Pd prompted So chemotactic moving toward Pd, which helped the two bacteria effectively obtain their required substances. Obviously, metabolite cross-feeding promoted NADH production and electron transfer, resulting in efficient SMX biodegradation by Pd and So in the presence of nitrate. Its feasibility was finally verified by the coculture of an activated sludge denitrifier and So.