Wang Yuan-Shan, Zheng Xing-Chang, Hu Qi-Wei, Zheng Yu-Guo
Institute of Bioengineering, Zhejiang University of Technology, No. 18, Chaowang Road, Hangzhou, Zhejiang 310014, PR China; Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, No. 18, Chaowang Road, Hangzhou, Zhejiang 310014, PR China.
Res Microbiol. 2015 Jun;166(5):408-418. doi: 10.1016/j.resmic.2015.04.002. Epub 2015 May 6.
An abamectin (ABM)-degrading bacterium, Stenotrophomonas maltophilia ZJB-14120, was isolated and identified. This strain is capable of degrading 84.82% of ABM at an initial concentration of 200 mg/L over a 48 h incubation period. This strain showed efficient biodegradation ability (7.81 mg/L/h) to ABM and high tolerance (1000 mg/L) to all macrolides tested. In addition to ABM, emamectin, erythromycin and spiramycin can also be degraded by this strain. Modifications involving either reduction of the double bond between C22-C23 or replacement of the C25-group of ABM with a cyclohexyl group can completely inhibit biodegradation of ABM. The ABM-degrading capability of strain ZJB-14120 is likely to be intrinsic to its metabolism and could be inhibited by incubating with erythromycin, azithromycin, spiramycin or rifampicin. A new and successive degradation pathway was proposed based on metabolite analysis. Although there is evidence for metabolite inhibition, this strain has high ABM degradation activity and reusability. Further investigation showed that activated macrolide efflux pump(s) and an undetermined mechanism for regulating the intracellular ABM concentration are responsible for normal uptake of essential metabolites while pumping out excess harmful compounds. Strain ZJB-14120 may provide efficient treatment of water and soil contaminated by toxic levels of abamectin and emamectin.
分离并鉴定出了一株阿维菌素（ABM）降解菌——嗜麦芽窄食单胞菌ZJB-14120。该菌株在初始浓度为200mg/L的条件下，经过48小时的培养期，能够降解84.82%的ABM。该菌株对ABM表现出高效的生物降解能力（7.81mg/L/h），并且对所有测试的大环内酯类药物具有高耐受性（1000mg/L）。除了ABM，该菌株还能降解甲氨基阿维菌素苯甲酸盐、红霉素和螺旋霉素。涉及C22-C23之间双键还原或用环己基取代ABM的C25基团的修饰可完全抑制ABM的生物降解。菌株ZJB-14120的ABM降解能力可能是其代谢所固有的，并且可以通过与红霉素、阿奇霉素、螺旋霉素或利福平一起孵育来抑制。基于代谢物分析提出了一种新的连续降解途径。尽管有代谢物抑制的证据，但该菌株具有高ABM降解活性和可重复使用性。进一步的研究表明，激活的大环内酯外排泵和一种未确定的调节细胞内ABM浓度的机制负责在泵出过量有害化合物的同时正常摄取必需代谢物。菌株ZJB-14120可能为有效处理被高毒性阿维菌素和甲氨基阿维菌素苯甲酸盐污染的水和土壤提供帮助。
