The removal of 17β-estradiol （E2） in laccase catalyzed oxidative coupling processes was systematically studied in this work. We focused on the influence of pH and natural organic matter （NOM） on the performance o...The removal of 17β-estradiol （E2） in laccase catalyzed oxidative coupling processes was systematically studied in this work. We focused on the influence of pH and natural organic matter （NOM） on the performance of the enzymatic treatment processes. It was found that the optimal pH for E2 removal was between 4 and 6. The removal of E2 was slightly inhibited in the presence of NOM. Enzymatic transformation of E2 was second-order in kinetics with first-order to both the concentrations of the enzyme and contaminant. Mass spectrum （MS） analysis suggested that coupling products were formed through radical-radical coupling mechanism. The results of this study demonstrated that laccase catalyzed oxidative coupling process could potentially serve as a treatment strategy to control steroid estrogens.展开更多
This work investigated the transformation of triclosan （TCS） by the laccase produced by a pathogen isolated from rotten tomato. The pathogen was characterized as Bot^tis sp. FQ, belonging to subphylum Deuteromw＇oti...This work investigated the transformation of triclosan （TCS） by the laccase produced by a pathogen isolated from rotten tomato. The pathogen was characterized as Bot^tis sp. FQ, belonging to subphylum Deuteromw＇otina. The laccase exhibited cold-adaptation with relatively high activity at 20℃. The laccase could effectively transform TCS. Approximately 62% TCS could be removed at dose of 1.0 unit·mL^-1 in 120min. The reaction rate appeared to be pseudo-first-order to the concentration of the substrate, suggesting the laccase activity remained stable during the reaction. Transformation products of TCS were analyzed by mass spectrometry and it was revealed that TCS dimers were formed via radical coupling pathways. During this process, laccase catalyzed oxidation of TCS to form a radical intermediate is the rate limiting step. However, this step can be reversed by humic acid. Overall, the laccase showed great potential in the treatment of phenolic contaminants. Since laccase is widely presented in natural environment, this study also revealed an important pathway involved in the transformation of phenolic contaminants in the environment.展开更多
基金This research was funded by the National Natural Science Foundation of China （Grant No. 51178224）, Jiangsu Natural Science Foundation （BIC2010443）, and the Priority Academic Program Development （PAPD） of Jiangsu Higher Education Institute. The content of the paper does not necessarily represent the views of the funding agencies.
文摘The removal of 17β-estradiol （E2） in laccase catalyzed oxidative coupling processes was systematically studied in this work. We focused on the influence of pH and natural organic matter （NOM） on the performance of the enzymatic treatment processes. It was found that the optimal pH for E2 removal was between 4 and 6. The removal of E2 was slightly inhibited in the presence of NOM. Enzymatic transformation of E2 was second-order in kinetics with first-order to both the concentrations of the enzyme and contaminant. Mass spectrum （MS） analysis suggested that coupling products were formed through radical-radical coupling mechanism. The results of this study demonstrated that laccase catalyzed oxidative coupling process could potentially serve as a treatment strategy to control steroid estrogens.
文摘This work investigated the transformation of triclosan （TCS） by the laccase produced by a pathogen isolated from rotten tomato. The pathogen was characterized as Bot^tis sp. FQ, belonging to subphylum Deuteromw＇otina. The laccase exhibited cold-adaptation with relatively high activity at 20℃. The laccase could effectively transform TCS. Approximately 62% TCS could be removed at dose of 1.0 unit·mL^-1 in 120min. The reaction rate appeared to be pseudo-first-order to the concentration of the substrate, suggesting the laccase activity remained stable during the reaction. Transformation products of TCS were analyzed by mass spectrometry and it was revealed that TCS dimers were formed via radical coupling pathways. During this process, laccase catalyzed oxidation of TCS to form a radical intermediate is the rate limiting step. However, this step can be reversed by humic acid. Overall, the laccase showed great potential in the treatment of phenolic contaminants. Since laccase is widely presented in natural environment, this study also revealed an important pathway involved in the transformation of phenolic contaminants in the environment.
