School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea.
Bioresour Technol. 2011 Feb;102(3):2206-12. doi: 10.1016/j.biortech.2010.10.009. Epub 2010 Oct 8.
The antimicrobial agent triclosan is an emerging and persistent environmental pollutant. This study evaluated the susceptibility and biodegradation potential of triclosan by three bacterial strains (Sphingomonas wittichii RW1, Burkholderia xenovorans LB400 and Sphingomonas sp. PH-07) that are able to degrade aromatic pollutants (dibenzofuran, biphenyl and diphenyl ether, respectively) with structural similarities to triclosan. These strains showed less susceptibility to triclosan when grown in complex and mineral salts media. Biodegradation experiments revealed that only strain PH-07 was able to catabolize triclosan to intermediates that included hydroxylated compounds (monohydroxy-triclosan, and dihydroxy-triclosan) and the ether bond cleavage products (4-chlorophenol and 2,4-dichlorophenol), indicating that the initial dihydroxylation occurred on both aromatic rings of triclosan. Additional growth inhibition tests demonstrated that the main intermediate, 2,4-dichlorophenol, was less toxic to strain PH-07 than was triclosan. Our results indicate that ether bond cleavage might be the primary mechanism of avoiding triclosan toxicity by this strain.
三氯生是一种新兴的持久性环境污染物。本研究评估了三氯生的敏感性和生物降解潜力，使用了三种能够降解具有与三氯生相似结构的芳香族污染物（二苯并呋喃、联苯和二苯醚）的细菌菌株（分别为：黄单胞菌 RW1、恶臭假单胞菌 LB400 和鞘氨醇单胞菌 PH-07）。当在复杂和无机盐介质中生长时，这些菌株对三氯生的敏感性较低。生物降解实验表明，只有 PH-07 菌株能够将三氯生代谢为包括羟基化化合物（单羟基三氯生和双羟基三氯生）和醚键断裂产物（4-氯苯酚和 2,4-二氯苯酚）在内的中间产物，表明三氯生的初始双羟基化发生在两个芳香环上。额外的生长抑制试验表明，主要中间产物 2,4-二氯苯酚对 PH-07 菌株的毒性比三氯生低。我们的结果表明，醚键断裂可能是该菌株避免三氯生毒性的主要机制。
