Jindrová E, Chocová M, Demnerová K, Brenner V
Institute of Microbiology, Academy of Sciences of the Czech Republic, Institute of Chemical Technology, Prague, Czechia.
Folia Microbiol (Praha). 2002;47(2):83-93. doi: 10.1007/BF02817664.
Several aerobic metabolic pathways for the degradation of benzene, toluene, ethylbenzene and xylene (BTEX), which are provided by two enzymic systems (dioxygenases and monooxygenases), have been identified. The monooxygenase attacks methyl or ethyl substituents of the aromatic ring, which are subsequently transformed by several oxidations to corresponding substituted pyrocatechols or phenylglyoxal, respectively. Alternatively, one oxygen atom may be first incorporated into aromatic ring while the second atom of the oxygen molecule is used for oxidation of either aromatic ring or a methyl group to corresponding pyrocatechols or protocatechuic acid, respectively. The dioxygenase attacks aromatic ring with the formation of 2-hydroxy-substituted compounds. Intermediates of the "upper" pathway are then mineralized by either ortho- or meta-ring cleavage ("lower" pathway). BTEX are relatively water-soluble and therefore they are often mineralized by indigenous microflora. Therefore, natural attenuation may be considered as a suitable way for the clean-up of BTEX contaminants from gasoline-contaminated soil and groundwater.
现已确定，由双加氧酶和单加氧酶这两种酶系统提供的几种用于降解苯、甲苯、乙苯和二甲苯（BTEX）的需氧代谢途径。单加氧酶攻击芳环的甲基或乙基取代基，随后分别通过几次氧化将其转化为相应的取代邻苯二酚或苯乙二醛。或者，一个氧原子可首先并入芳环，而氧分子的第二个原子则分别用于将芳环或甲基氧化为相应的邻苯二酚或原儿茶酸。双加氧酶攻击芳环并形成2-羟基取代化合物。然后，“上游”途径的中间体通过邻位或间位环裂解（“下游”途径）被矿化。BTEX相对易溶于水，因此它们通常被本地微生物群落矿化。因此，自然衰减可被视为从汽油污染的土壤和地下水中清除BTEX污染物的一种合适方法。
