Dept. of Environmental Protection, Estación Experimental Del Zaidín - CSIC, Calle Professor Albareda 1, 18008, Granada, Spain.
Unidad de Resonancia Magnética Nuclear, Centro de Instrumentación Científica, Universidad de Granada, Paseo Juan Osorio S/n, 18071, Granada, Spain.
Environ Pollut. 2021 Apr 1;274:116536. doi: 10.1016/j.envpol.2021.116536. Epub 2021 Jan 24.
The high global consumption of ibuprofen and its limited elimination by wastewater treatment plants (WWTPs), has led to the contamination of aquatic systems by this common analgesic and its metabolites. The potentially negative environmental and public health effects of this emerging contaminant have raised concerns, driving the demand for treatment technologies. The implementation of bacteria which mineralize organic contaminants in biopurification systems used to decontaminate water or directly in processes in WWTPs, is a cheap and sustainable means for complete elimination before release into the environment. In this work, an ibuprofen-mineralizing bacterial strain isolated from sediments of the River Elbe was characterized and assayed to remediate different ibuprofen-polluted media. Strain RW412, which was identified as Sphingopyxis granuli, has a 4.48 Mb genome which includes plasmid sequences which harbor the ipf genes that encode the first steps of ibuprofen mineralization. Here, we confirm that these genes encode enzymes which initiate CoA ligation to ibuprofen, followed by aromatic ring activation by a dioxygenase and retroaldol cleavage to unequivocally produce 4-isobutylcatechol and propionyl-CoA which then undergo further degradation. In liquid mineral salts medium, the strain eliminated more than 2 mM ibuprofen within 74 h with a generation time of 16 h. Upon inoculation into biopurification systems, it eliminated repeated doses of ibuprofen within a few days. Furthermore, in these systems the presence of RW412 avoided the accumulation of ibuprofen metabolites. In ibuprofen-spiked effluent from a municipal WWTP, ibuprofen removal by this strain was 7 times faster than by the indigenous microbiota. These results suggest that this strain can persist and remain active under environmentally relevant conditions, and may be a useful innovation to eliminate this emerging contaminant from urban wastewater treatment systems.
布洛芬在全球范围内的高消耗量及其在废水处理厂（WWTP）中的有限去除率，导致这种常见的镇痛剂及其代谢物对水生系统造成了污染。这种新兴污染物对环境和公共健康可能产生的负面影响引起了人们的关注，从而推动了对处理技术的需求。在生物净化系统中引入能够矿化有机污染物的细菌，用于净化水或直接在 WWTP 中的处理过程中，是在将其排放到环境中之前进行完全去除的一种廉价且可持续的方法。在这项工作中，从易北河沉积物中分离出一株能够矿化布洛芬的细菌菌株，并对其进行了特征描述和检测，以修复不同受布洛芬污染的介质。该菌株 RW412 被鉴定为 Sphingopyxis granuli，其基因组大小为 4.48 Mb，其中包括质粒序列，这些质粒序列携带有编码布洛芬矿化的初始步骤的 ipf 基因。在这里，我们证实这些基因编码的酶能够将 CoA 连接到布洛芬上，然后由双加氧酶激活芳环，并通过逆醛缩酶裂解产生明确的 4-异丁基儿茶酚和丙酰 CoA，然后进一步降解。在液体矿物盐培养基中，该菌株在 74 小时内消除了超过 2 mM 的布洛芬，其代时为 16 小时。接种到生物净化系统中后，它在几天内就消除了重复剂量的布洛芬。此外，在这些系统中，RW412 的存在避免了布洛芬代谢物的积累。在市 WWTP 的含布洛芬废水的流出物中，该菌株对布洛芬的去除速度比土著微生物群快 7 倍。这些结果表明，该菌株在环境相关条件下能够持续存在并保持活性，并且可能是从城市废水处理系统中消除这种新兴污染物的有用创新。
