Roles of tert-butyl formate, tert-butyl alcohol and acetone in the regulation of methyl tert-butyl ether degradation by Mycobacterium austroafricanum IFP 2012
Roles of tert-butyl formate, tert-butyl alcohol and acetone in the regulation of methyl tert-butyl ether degradation by Mycobacterium austroafricanum IFP 2012
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DOI：
10.1007/s00253-003-1268-9
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发表时间：
2003-08-01
影响因子：
5
通讯作者：
Monot, F
中科院分区：
文献类型：
--
作者：
Francois, A;Garnier, L;Monot, F
非洲南部分枝杆菌IFP 2012是一种革兰氏阳性菌株，能够在甲基叔丁基醚（MTBE）作为唯一碳源和能源上生长。利用静息细胞研究了MTBE的两种下游代谢产物甲酸叔丁酯（TBF）和叔丁醇（TBA）对MTBE降解的影响。低浓度TBF的加入使MTBE的降解率降低了约30%。与此相反，TBA的加入没有显着的影响，对MTBE的降解率，即使在高浓度下，它也表明，TBA降解发生红色只有一旦MTBE耗尽。在中性pH下，TBF水解主要涉及由TBA的存在下调节的酯酶型活性。TBF的降解速率比MTBE的降解速率低约4倍。此外，丙酮被确定为TBA降解过程中的中间体。丙酮单加氧酶活性，抑制甲巯咪唑，但不乙炔，建议。它与MTBE/TBA单加氧酶不同，因此丙酮似乎不会与MTBE和TBA竞争相同的酶。这些新的结果表明，甲基叔丁基醚降解的早期阶段的代谢调控M。austroafricanum IFP 2012是复杂的，涉及抑制和竞争现象。
Mycobacterium austroafricanum IFP 2012 is a Gram-positive strain able to grow on methyl tert-butyl ether (MTBE) as a sole carbon and energy source. The effect of two downstream metabolites of MTBE, tertbutyl formate (TBF) and tert-butyl alcohol (TBA) on MTBE degradation was investigated using resting cells. The addition of low concentrations of TBF decreased the MTBE degradation rate by about 30%. In contrast, the addition of TBA did not have a significant effect on MTBE degradation rate, even at high concentrations; and it was also shown that TBA degradation occur-red only once MTBE was exhausted. At neutral pH, TBF hydrolysis involved mainly an esterase-type activity regulated by the presence of TBA. The TBF degradation rate was about four times lower than the MTBE degradation rate. Furthermore, acetone was identified as an intermediate during TBA degradation. An acetone mono-oxygenase activity, inhibited by methimazole but not by acetylene, was suggested. It was different from the MTBE/TBA mono-oxygenase and, thus, acetone did not appear to compete with MTBE and TBA for the same enzyme. These new results show that the metabolic regulation of the early steps of MTBE degradation by M. austroafricanum IFP 2012 is complex, involving inhibition and competition phenomena.