Cometabolism of methyl tert-butyl ether (MTBE) with alkanes
Cometabolism of methyl tert-butyl ether (MTBE) with alkanes
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DOI：
10.1007/s11157-006-9119-7
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发表时间：
2007-10-01
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影响因子：
--
通讯作者：
Revah, Sergio
中科院分区：
文献类型：
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作者：
Nava, Veronica;Morales, Marcia;Revah, Sergio
甲基叔丁基醚（MTBE）主要通过损坏的汽油地下储罐或分配系统泄漏释放到环境中，引起了广泛的地下水污染。一般来说，生物处理是污染场地生物修复的一种良好选择；然而，由于甲基叔丁基醚的化学结构和理化性质，使其在环境中的消除成为一项挑战。稳定的醚连接和支链部分的结合阻碍了生物降解。最初的研究发现MTBE具有很强的抗逆性，但在过去十年中，关于其生物降解的报告首次在有氧条件下发表，最近在厌氧条件下发表。微生物降解MTBE的特点是细菌具有较低的生长速度（0.35天（-1））和生物量产量（平均值0.24 g生物量/g MTBE）。另外，共代谢（定义为非生长底物在生长底物的专门存在下的转化）也被认为是由于它使污染物的生物降解与生长分离，减少了漫长的适应和繁殖周期。据报道，在它作为唯一碳源被降解的系统中，这一时期长达几个月。共代谢降解率在0.3 ~ 61 nmol/min/mg蛋白质之间（与直接有氧代谢相同）。然而，MTBE共代谢的一个主要问题是，在某些情况下，叔丁醇（TBA）的积累可能导致位点清除不完全。本文详细综述了以烷烃为生长底物降解甲基叔丁基醚的共代谢过程中涉及的酶和现场处理。
The release of methyl tert-butyl ether (MTBE) to the environment, mainly from damaged gasoline underground storage tanks or distribution systems spills, has provoked extended groundwater pollution. Biological treatments are, in general, a good alternative for bioremediation of polluted sites; however, MTBE elimination from environment has constituted a challenge because of its chemical structure and physicochemical properties. The combination of a stable ether link and the branched moiety hinder biodegradation. Initial studies found MTBE to be highly recalcitrant but, in the last decade, reports of its biodegradation have been published first under aerobic conditions and just recently under anaerobic conditions. Microbial MTBE degradation is characterized by bacteria having low growth rates (0.35 day(-1)) and biomass yields (average value 0.24 g biomass/g MTBE). Alternatively, cometabolism (defined as the transformation of a non-growth substrate in the obligate presence of a growth substrate), has been considered since it uncouples biodegradation of the contaminant from growth, reducing the long adaptation and propagation period. This period has been reported to be of several months in systems where it is degraded as sole carbon source. Cometabolic degradation rates are between 0.3 and 61 nmol/min/mg protein (in the same range of direct aerobic metabolism). However, a major concern in MTBE cometabolism is that the accumulation of tert-butyl alcohol (TBA) may, under certain cases, result in an incomplete site cleanup. This paper reviews in detail the implicated enzymes and field treatments for the cometabolism of MTBE degradation with alkanes as growth substrates.