Chen Jianmeng, Chen Dongzhi, Zhong Weihong, Zhang Jingxiao, Chen Xiao
College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2007 Dec;42(14):2123-9. doi: 10.1080/10934520701629492.
In this study, degradation of methyl tert-butyl ether (MTBE) by resting cells of Methylibium petroleiphilum PM1 was performed in poor nutrition solution, major component of which was MTBE. It was found that the biomass was hard to increase in poor nutrition, and the MTBE degradation activity was enhanced by 4.65-fold when 1 mM of Ba(2+) was added into deionized water. It was also found that the MTBE degradation could be significantly improved by the dissolved oxygen level. All of 50 mg L(-1) MTBE could be degraded under aerobic condition, while only 5% was degraded under anaerobic condition by resting cells in poor nutrition solution after 12 h. In the above solution, the degradation of tert-butyl alcohol (TBA) was found to be faster than that of MTBE, which suggested that TBA degradation might not be the limiting step in MTBE metabolism. While in the poor nutrition solution with the mixture of MTBE and TBA, the addition of TBA did not affect MTBE degradation while MTBE inhibited TBA degradation weakly, which suggested that different and independent enzymes were responsible for degrading such compounds. The success of MTBE degradation by PM1 cells in real contaminated groundwater demonstrated its feasibility to biodegrade MTBE under poor environment, and it also indicated the great potential of MTBE bioremediation by entrapped cells in future application.
在本研究中，以甲基叔丁基醚（MTBE）作为主要营养成分的贫营养溶液中，利用嗜油甲基杆菌PM1的静息细胞进行MTBE降解实验。结果发现，在贫营养条件下生物量难以增加，而向去离子水中添加1 mM Ba(2+)时，MTBE降解活性提高了4.65倍。还发现溶解氧水平可显著改善MTBE降解。在好氧条件下，50 mg L(-1)的MTBE可全部降解，而在厌氧条件下，贫营养溶液中的静息细胞12 h后仅降解5%。在上述溶液中，发现叔丁醇（TBA）的降解速度比MTBE快，这表明TBA降解可能不是MTBE代谢的限速步骤。而在含有MTBE和TBA混合物的贫营养溶液中，添加TBA不影响MTBE降解，MTBE对TBA降解的抑制作用较弱，这表明降解这些化合物的是不同且独立的酶。PM1细胞在实际受污染地下水中成功降解MTBE，证明了其在恶劣环境下生物降解MTBE的可行性，也表明固定化细胞在未来应用中对MTBE进行生物修复具有巨大潜力。
