Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
Sci Total Environ. 2022 Mar 1;810:152218. doi: 10.1016/j.scitotenv.2021.152218. Epub 2021 Dec 7.
Atenolol is a widely prescribed beta-blocker that has been detected in wastewater at concentrations up to 300 μg/L. The parent compound and its transformation products pose risks to aquatic organisms. Efficient atenolol degrading microorganism has yet to be identified, and its biodegradation pathway is unknown. In this study, Hydrogenophaga sp. YM1 isolated from activated sludge can degrade atenolol efficiently (286.1 ± 4.0 μg/g dry wt/h in actual wastewater), where atenolol acid, and four newly detected products (4-hydroxyphenylacetic acid, 3-(isopropylamino)-1,2-propanediol, 3-amino-1,2-propanediol and 4-(1-amino-2-hydroxy-3-propoxy) benzeneacetic acid) were the main intermediates. Key genes involved in atenolol degradation were proposed based on RNA-seq and validated by RT-qPCR. The ether bond cleavage of atenolol acid was the rate-limiting step likely catalyzed by the α-ketoglutarate dependent 2,4-dichlorophenoxyacetate dioxygenase. The further degradation of 4-hydroxyphenylacetic acid followed the homoprotocatechuate degradation pathway, enabling complete conversion to CO. Acetate addition (39-156 mg COD/L) under aerobic condition enhanced atenolol degradation by 29-37% and decreased the accumulation of atenolol acid, likely because acetate oxidation provided α-ketoglutarate and additional reducing power. Activated sludge core microorganisms have limited atenolol mineralization potentials. Enriching Hydrogenophaga-like populations and/or providing such as acetate can drive more complete conversion of atenolol in natural and engineered biosystems.
阿替洛尔是一种广泛应用的β受体阻滞剂，其在废水中的浓度高达 300μg/L。母体化合物及其转化产物对水生生物构成风险。目前尚未鉴定出高效降解阿替洛尔的微生物，其生物降解途径也未知。在本研究中，从活性污泥中分离出的噬氢菌（Hydrogenophaga sp. YM1）可以有效降解阿替洛尔（实际废水中 286.1±4.0μg/g 干重/小时），其中阿替洛尔酸和四种新检测到的产物（4-羟基苯乙酸、3-（异丙氨基）-1,2-丙二醇、3-氨基-1,2-丙二醇和 4-（1-氨基-2-羟基-3-丙氧基）苯乙酸）是主要的中间产物。基于 RNA-seq 提出了参与阿替洛尔降解的关键基因，并通过 RT-qPCR 进行了验证。阿替洛尔酸醚键的断裂可能是由α-酮戊二酸依赖的 2,4-二氯苯氧乙酸双加氧酶催化的限速步骤。4-羟基苯乙酸的进一步降解遵循原儿茶酸降解途径，可将其完全转化为 CO。在好氧条件下添加乙酸（39-156mg COD/L）可使阿替洛尔的降解提高 29-37%，并减少阿替洛尔酸的积累，这可能是因为乙酸氧化提供了α-酮戊二酸和额外的还原力。活性污泥核心微生物对阿替洛尔的矿化潜力有限。富集类似噬氢菌的种群和/或提供乙酸等物质可以促进自然和工程生物系统中更完全地转化阿替洛尔。
