Centre of Marine Sciences (CCMAR/CIMAR LA), University of the Algarve, Gambelas Campus, Faro, Portugal.
Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Seville, Spain.
Environ Microbiol Rep. 2024 Aug;16(4):e13320. doi: 10.1111/1758-2229.13320.
Ibuprofen (IBU) is a significant contaminant frequently found in wastewater treatment plants due to its widespread use and limited removal during treatment processes. This leads to its discharge into the environment, causing considerable environmental concerns. The use of microorganisms has recently been recognized as a sustainable method for mitigating IBU contamination in wastewater. In this study, new bacteria capable of growing in a solid medium with IBU as the only carbon source and removing IBU from a liquid medium were isolated from environmental samples, including soil, marine, mine, and olive mill wastewater. Four bacterial strains, namely Klebsiella pneumoniae TIBU2.1, Klebsiella variicola LOIBU1.1, Pseudomonas aeruginosa LOIBU1.2, and Mycolicibacterium aubagnense HPB1.1, were identified through 16S rRNA gene sequencing. These strains demonstrated significant IBU removal efficiencies, ranging from 60 to 100% within 14 days, starting from an initial IBU concentration of 5 mg per litre. These bacteria have not been previously reported in the literature as IBU degraders, making this work a valuable contribution to further studies in the field of bioremediation in environments contaminated by IBU. Based on the IBU removal results, the most promising bacteria, K. pneumoniae TIBU2.1 and M. aubagnense HPB1.1, were selected for an in silico analysis to identify genes potentially involved in IBU biodegradation. Interestingly, in the tests with TIBU2.1, a peak of IBU transformation product(s) was detected by high-performance liquid chromatography, while in the tests with HPB1.1, it was not detected. The emerging peak was analysed by liquid chromatography-mass spectrometry, indicating the presence of possible conjugates between intermediates of IBU biodegradation. The proteins encoded on their whole-genome sequences were aligned with proteins involved in an IBU-degrading pathway reported in bacteria with respective catabolic genes. The analysis indicated that strain HPB1.1 possesses genes encoding proteins similar to most enzymes reported associated with the IBU metabolic pathways used as reference bacteria, while strain TIBU2.1 has genes encoding proteins similar to enzymes involved in both the upper and the lower part of that pathway. Notably, in the tests with the strain having more candidate genes encoding IBU-catabolic enzymes, no IBU transformation products were detected, while in the tests with the strain having fewer of these genes, detection occurred.
布洛芬（IBU）是一种常见的污染物，由于其广泛应用和在处理过程中去除效率有限，经常在废水处理厂中被发现。这导致其排放到环境中，引起了相当大的环境关注。最近，人们已经认识到利用微生物是减轻废水中 IBU 污染的一种可持续方法。在这项研究中，从环境样本（包括土壤、海洋、矿山和橄榄油厂废水）中分离出了能够在含有 IBU 的固体培养基中生长并从液体培养基中去除 IBU 的新细菌。通过 16S rRNA 基因测序，鉴定了 4 株细菌，分别为肺炎克雷伯菌 TIBU2.1、奇异变形杆菌 LOIBU1.1、铜绿假单胞菌 LOIBU1.2 和非洲分枝杆菌 HPB1.1。这些菌株在 14 天内从初始 IBU 浓度为 5mg/L 开始，表现出高达 60-100%的 IBU 去除效率。这些细菌以前没有被文献报道为 IBU 降解菌，这使得这项工作对进一步研究 IBU 污染环境中的生物修复具有重要意义。根据 IBU 去除结果，选择最有前途的细菌肺炎克雷伯菌 TIBU2.1 和非洲分枝杆菌 HPB1.1 进行计算机分析，以鉴定可能参与 IBU 生物降解的基因。有趣的是，在 TIBU2.1 的测试中，通过高效液相色谱法检测到 IBU 转化产物的峰值，而在 HPB1.1 的测试中则没有检测到。通过液相色谱-质谱分析，表明存在 IBU 生物降解中间产物的可能缀合物。它们全基因组序列编码的蛋白质与具有相应代谢基因的报告细菌中 IBU 降解途径的蛋白质进行了比对。分析表明，HPB1.1 菌株具有编码与作为参考细菌的 IBU 代谢途径相关的大多数酶相似的蛋白质的基因，而 TIBU2.1 菌株具有编码参与该途径上下部分的酶相似的蛋白质的基因。值得注意的是，在具有更多候选基因编码 IBU 代谢酶的菌株的测试中，没有检测到 IBU 转化产物，而在具有较少这些基因的菌株的测试中，则检测到了 IBU 转化产物。
