Enhanced catalytic activity and thermal stability of 2,4-dichlorophenol hydroxylase by using microwave irradiation and imidazolium ionic liquid for 2,4-dichlorophenol removal
Enhanced catalytic activity and thermal stability of 2,4-dichlorophenol hydroxylase by using microwave irradiation and imidazolium ionic liquid for 2,4-dichlorophenol removal
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DOI：
10.1039/c4ra10637g
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发表时间：
2014-11
期刊：
影响因子：
3.9
通讯作者：
Hejun Ren;Yang Zhan;Xuexun Fang;Dahai Yu
中科院分区：
文献类型：
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作者：
Hejun Ren;Yang Zhan;Xuexun Fang;Dahai Yu
酶法脱除2，4-二氯苯酚(2，4-DCP)具有高效、低成本、环保等优点，近年来受到人们的广泛关注。以微波辐射为加热方式，以离子液体(IL)为添加剂，获得了脱除2，4-DCP的高活性2，4-DCP羟基酶。[EMIM][PF6](1-乙基-3-甲基咪唑六氟磷酸)和微波辐射均能提高2，4-DCP羟基酶的脱除效率和热稳定性，且微波辐射和[EMIM][PF6]对提高2，4-DCP脱除效率和酶的热稳定性有进一步的促进作用。对2，4-二氯环己烷的脱除条件进行了优化，在25℃下脱除2，4-二氯环己烷的时间为15min，酶活为0.66±0.015 mg−-1，大大快于目前需要数小时才能完全脱除2，4-二氯环己烷的酶促脱除方法。在4℃下，2，4-DCP羟基酶仅需30min即可完全去除2，4-DCP，表明其具有耐冷性。这些结果表明，微波作用下的2，4-DCP羟基酶在[EMIM][PF6]中是一种快速、高效、环境友好的脱除2，4-DCP的方法，该方法具有较宽的温度范围。
Enzymatic removal of 2,4-dichlorophenol (2,4-DCP) has become more attractive recently due to its high efficiency, low cost and environmental benefits. A highly active 2,4-DCP hydroxylase for 2,4-DCP removal was obtained and used in 2,4-DCP removal by employing microwave irradiation as a heating mode and ionic liquid (IL) as an additive. Both [EMIM][PF6] (1-ethyl-3-methylimidazolium hexafluorophosphate) and microwave irradiation were found to increase the 2,4-DCP removal efficiency and the thermal stability of 2,4-DCP hydroxylase, and a further incremental effect of microwave irradiation and [EMIM][PF6] on improving the 2,4-DCP removal efficiency and enzymatic thermal stability was observed. Conditions for 2,4-DCP removal were optimized and the removal of 2,4-DCP was completed in 15 min at 25 °C with 0.66 ± 0.015 U mg−1 enzyme activity under the optimum conditions, much faster than the present enzymatic removal route, which took several hours for complete 2,4-DCP removal. Only 30 min were required for complete 2,4-DCP removal by using the 2,4-DCP hydroxylase at 4 °C, indicating its psychrotrophic adaptability. These results showed that the use of 2,4-DCP hydroxylase under microwave in [EMIM][PF6] is a fast, efficient and environmentally benign method for the removal of 2,4-DCP, and this method can be used over a wide temperature range.