College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, P. R. China.
Environ Sci Technol. 2022 Aug 16;56(16):11277-11287. doi: 10.1021/acs.est.2c00062. Epub 2022 Jul 29.
Tetrabromobisphenol A (TBBPA) has extensive applications in various fields; its release into ecosystems and the potential toxic effects on organisms are becoming major concerns. Here, we investigated the effects of TBBPA on anaerobic digestion, whose process is closely related to the carbon cycles under anaerobic conditions. The results revealed that TBBPA exhibited dose-dependent hormesis-like effects on methane production from glucose, i.e., the presence of 0.1 mg/L TBBPA increased the methane production rate by 8.79%, but 1.0-4.0 mg/L TBBPA caused 3.45-28.98% of decrement. We found that TBBPA was bound by the tyrosine-like proteins of the extracellular polymeric substances of anaerobes and induced the increase of reactive oxygen species, whose slight accumulation stimulated the metabolism activities but high accumulation increased the apoptosis of anaerobes. Owing to the differences between individual anaerobes in tolerance, TBBPA at 0.1 mg/L stimulated the acidogenesis and hydrogenotrophic methanogenesis, whereas higher levels (i.e., 1.0-4.0 mg/L) severely restrained all of the processes of acidogenesis, acetogenesis, and methanogenesis. Along with the accumulation of bisphenol A (BPA) produced from TBBPA by sp. and sp., the methanogenic pathway was partly shifted from acetate-dependent to hydrogen-dependent direction, and the activities of carbon monoxide dehydrogenase and acetyl-CoA decarbonylase/synthase were inhibited, while acetate kinase and F420 were hormetically affected. These findings elucidated the mechanism of anaerobic syntrophic consortium responses to TBBPA, supplementing the potential environmental risks of brominated flame retardants.
四溴双酚 A（TBBPA）在各个领域都有广泛的应用，其释放到生态系统中以及对生物体的潜在毒性作用正成为人们关注的主要问题。在这里，我们研究了 TBBPA 对厌氧消化的影响，其过程与厌氧条件下的碳循环密切相关。结果表明，TBBPA 对葡萄糖产甲烷表现出剂量依赖性的激素样效应，即 0.1mg/L 的 TBBPA 使甲烷生成率增加了 8.79%，而 1.0-4.0mg/L 的 TBBPA 则导致甲烷生成率下降了 3.45-28.98%。我们发现 TBBPA 与厌氧菌细胞外聚合物中的酪氨酸样蛋白结合，并诱导活性氧的增加，其轻微积累刺激了代谢活动，但高浓度则增加了厌氧菌的凋亡。由于个体厌氧菌对 TBBPA 的耐受性不同，0.1mg/L 的 TBBPA 刺激了产酸和氢营养型甲烷生成，而更高水平（即 1.0-4.0mg/L）则严重抑制了产酸、乙酰化和甲烷生成的所有过程。随着 sp. 和 sp. 产生的 TBBPA 转化为双酚 A（BPA）的积累，产甲烷途径部分从依赖乙酸转向依赖氢气，一氧化碳脱氢酶和乙酰辅酶 A 脱羧酶/合成酶的活性受到抑制，而乙酸激酶和 F420 则受到激素样影响。这些发现阐明了厌氧共培养物对 TBBPA 反应的机制，补充了溴化阻燃剂的潜在环境风险。
