一株邻苯二甲酸酯降解菌Salipiger sp.D13基因组特征及其降解能力

Genomic Features of Salipiger sp.D13 and its Degradation Ability on Phthalates

为了明确菌株Salipiger sp.D13对邻苯二甲酸酯(Phthalates esters,PAEs)的降解特性,对菌株Salipiger sp.D13基因组序列和对邻苯二甲酸酯的降解能力进行研究;同时,根据关键酶基因和中间代谢物,推测Salipiger sp.D13代谢邻苯二甲酸二正丁酯(DBP)的完整途径。试验结果表明:菌株Salipiger sp.D13含有降解邻苯二甲酸酯的关键酶基因,分布在多环芳烃降解和苯甲酸代谢等代谢途径中,对6种优先级控制PAEs的5 d降解率均在90%以上;菌株Salipiger sp.D13降解邻苯二甲酸酯二丁酯(DBP)的完整途径为邻苯二甲酸二丁酯通过酯酶水解为邻苯二甲酸(PA),PA通过加氧酶、脱氢酶、脱羧酶生成原儿茶酸(PCA),PCA通过原儿茶酸3,4-加氧酶(protocatechuate 3,4-dioxygenase)开环,形成β-carboxy-muconate等物质,从而进入三羧酸循环。试验结果可为菌株Salipiger sp.D13用作邻苯二甲酸酯类污染环境生物修复的候选菌株提供理论基础。

In order to clarify the degradation characteristics of the strain of Salipiger sp.D13 on phthalates,the genomic sequence of Salipiger sp.D13 and the degradation ability of this strain on phthalates were analyzed.Meanwhile,according to the key enzyme gene and intermediate metabolites,the complete pathway of Salipiger sp.D13 to metabolize DBP was speculated.The results showed that the strain of Salipiger sp.D13 contained the key enzyme genes for the degradation of phthalates,which were distributed in the metabolic pathways such as the degradation of polycyclic aromatic hydrocarbons and the metabolism of benzoic acid,and the 5-day degradation rates of the six priority controlled PAEs by the strain of Salipiger sp.D13 were all above 90%.The complete pathway of Salipiger sp.D13 to degrade dibutyl phthalate was that:dibutyl phthalate was hydrolyzed to phthalic acid(PA)by esterase.3,and PA produced protocatechuic acid(PCA)by oxygenase,dehydrogenase and decarboxylase,and then PCA was hydrolyzed to the substances such asβ-carboxy-muconate by ring opening reaction with protocatechuate 3,4-dioxygenase,which were then delivered to the tricarboxylic acid cycle.The experimental results could provide a theoretical basis for the application of Salipiger sp.D13 as a candidate strain for the environmental bioremediation of phthalate ester pollutants.