Heilongjiang Province Key Laboratory of Cold Region Wetland Ecology and Environment Research, School of Geography and Tourism, Harbin University, Harbin, 150086, China; National Technology Innovation Center of Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
Shanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
Sci Total Environ. 2022 Nov 15;847:157619. doi: 10.1016/j.scitotenv.2022.157619. Epub 2022 Jul 25.
As an emerging pollutant, benzalkonium chlorides (BACs) potentially enriched in waste activated sludge (WAS). However, the microbial response mechanism under chronic effects of BACs on acidogenesis and methanogenesis in anaerobic digestion (AD) has not been clearly disclosed. This study investigated the AD (by-)products and microbial evolution under low to high BACs concentrations from bioreactor startup to steady running. It was found that BACs can lead to an increase of WAS hydrolysis and fermentation, but a disturbance to acidogenic bacteria also occurred at low BACs concentration. A noticeable inhibition to methanogenesis occurred when BAC concentration was up to 15 mg/g TSS. Metagenomic analysis revealed the key genes involved in acetic acid (HAc) biosynthesis (i.e. phosphate acetyltransferase, PTA), β-oxidation pathway (acetyl-CoA C-acetyltransferase) and propionic acid (HPr) conversion was slightly promoted compared with control. Furthermore, BACs inhibited the acetotrophic methanogenesis (i.e. acetyl-CoA synthetase), especially BAC concentration was up to 15 mg/g TSS, thereby enhanced short chain fatty acids (SCFAs) accumulation. Overall, chronic stimulation of functional microorganisms with increasing concentrations of BACs impact WAS fermentation.
作为一种新兴污染物，季铵盐（BACs）可能在废活性污泥（WAS）中富集。然而，BACs 对厌氧消化（AD）中产酸和产甲烷的慢性影响下微生物的响应机制尚未明确揭示。本研究从生物反应器启动到稳定运行，调查了低至高 BACs 浓度下的 AD（副）产物和微生物进化。结果表明，BACs 可导致 WAS 水解和发酵增加，但在低 BACs 浓度下也会对产酸菌产生干扰。当 BAC 浓度达到 15mg/g TSS 时，对产甲烷作用会产生明显的抑制。宏基因组分析显示，与对照组相比，涉及乙酸（HAc）生物合成（即磷酸转乙酰酶，PTA）、β-氧化途径（乙酰辅酶 A C-乙酰转移酶）和丙酸（HPr）转化的关键基因略有促进。此外，BACs 抑制了乙酸营养型产甲烷作用（即乙酰辅酶 A 合成酶），特别是当 BAC 浓度达到 15mg/g TSS 时，从而促进了短链脂肪酸（SCFAs）的积累。总体而言，随着 BACs 浓度的增加，功能微生物受到慢性刺激，影响了 WAS 的发酵。
