中国南海Bukholderia sp. DA2菌株降解邻苯二甲酸二甲酯研究

Biodegradation of dimethyl phthalate by Burkholderia sp. DA2 isolated from marine sediments in the South China Sea

以邻苯二甲酸二甲酯(dimethyl phthalate,DMP)为惟一碳源,从中国南海底泥中分离筛选到一株高效降解菌株,即伯克霍尔德氏菌Bukholderia.sp.DA2。该菌株降解DMP及其邻苯二甲酸二甲酯(Dimethyl phthalate,DMT)和间苯二甲酸二甲酯(Dimethyl dimethyl isophthalate,DMI)2种异构体的效果显著。B.sp.DA2菌株能够在8d内好氧降解矿化100mg·L-1的DMT,15d内好氧降解矿化400mg·L-1的DMP。但对于200mg·L-1的DMI,则不能彻底降解矿化,反应终止在生成间苯二甲酸一甲酯中间产物的阶段。研究表明,B.sp.DA2菌株降解DMT及DMP的途径相似,首先脱酯生成单酯和甲醇,继而水解酸化,直至彻底矿化。降解速率及其途径,与化学结构密切相关。

Burkholderia sp.DA2 strain isolated from marine sediments in the South China Sea was capable of utilizing dimethyl phthalate（DMP） as the sole source of carbon and energy for biodegradation of DMP,DMT（dimethyl phthalate） and DMI（dimethyl isophthalate）.During the transformation of DMP（400mg·L-1）,its corresponding intermediates were identified as mono-methyl phthalate（MMP） and phthalate acid（PA） by HPLC analysis.By the 9th day,the DMP concentration was undetectable in the culture,corresponding to a DMP decrease;MMP accumulated to 38.9 mg/L during eight days,at the same time amount of PA was also produced during the first 12 days of degradation;this PA was completely degraded after 15 days.During the transformation of DMT（100mg·L-1）,80% DMT was transferred into MMT in one day,but the MMT could not degraded rapidly and accumulated to 80.2mg·L-1,and completely mineralized during eight days.During the DMI（200mg·L-1） degradation,the DMI was transferred into MMI after six days,but the MMI could not further mineralize.Maybe the com-pounds chemical structures infect the activity of the enzyme degradation.The biodegradation pathway of DMP,DMT and DMI was proposed as DMP／DMT／DMI→MMP／MMT／MMI→PA／TA／IA→...→CO2＋H2O.