Degradation of Dimethyl Isophthalate by Viarovorax paradoxus Strain T4 Isolated from Deep-Ocean Sediment of the South China Sea
Degradation of Dimethyl Isophthalate by Viarovorax paradoxus Strain T4 Isolated from Deep-Ocean Sediment of the South China Sea
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DOI：
10.1080/10807030500531521
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发表时间：
2006-04
期刊：
影响因子：
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通讯作者：
Y. P. Wang;J. Gu
中科院分区：
文献类型：
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作者：
Y. P. Wang;J. Gu
摘要从深海沉积物中分离到一株能降解丁二酸二甲酯的奇异食环菌T4。当柠檬酸作为唯一的碳源和能源时，它首先通过水解转化，形成作为降解中间体的柠檬酸单甲酯（MMI）和柠檬酸（IA）。在约100 h内，MMI和NTA分别完全转化为MMI和IA。IA的降解在55 h左右完成。培养基中总有机碳的分析证实，超过80%的底物碳被矿化。以对硝基苯酚乙酸酯为底物，采用粗酶制剂，可测定多种底物诱导的细菌酯酶活性。由米氏方程推导出Km值的下降趋势为邻苯二甲酸二甲酯（DMP）>邻苯二甲酸单甲酯（MMP）>对苯二甲酸二甲酯（DMT）>肝酯酶>肝酯酶> MMI >对苯二甲酸单甲酯（MMT），表明双酯比单酯获得更高的Km值，且对苯二甲酸酯诱导的酯具有最高的活性。本研究表明，邻苯二甲酸酯的生化途径有许多共同的特点，不同底物诱导的酯酶具有高度的特异性。
ABSTRACT Viarovorax paradoxusT4 strain was isolated from deep-ocean sediment and demonstrated to be able to degrade dimethyl isophthalate (DMI). When DMI was utilized as the sole source of carbon and energy, it was transformed by hydrolysis initially, forming monomethyl isophthalate (MMI) and isophthalate acid (IA) as degradation intermediates. DMI and MMI were completely transformed to MMI and IA in about 100 h, respectively. Degradation of IA was completed in about 55 h. Analysis of total organic carbon in the culture medium confirmed that more than 80% of the substrate carbon was mineralized. Bacterial esterase induced by a range of substrates could be assessed using p-nitrophenyl acetate as the common substrate using crude enzyme preparation. The decreasing trend of K m values derived from the Michaelis–Menten equation was dimethyl phthalate (DMP) > monomethyl phthalate (MMP) > dimethyl terephthalate (DMT) > Liver esterase > DMI > MMI > monomethyl terephthalate (MMT), indicating that higher K m values were obtained by di-esters than mono-ester and the esters induced by terephthalate esters showed the highest activity. This investigation suggests that biochemical pathways for phthalate esters share many common characteristics and the esterases induced by different substrates are highly specific.