邻苯二甲酸酯高效降解菌的筛选及表征

Screening and Characterization of an Efficient Phthalate-Ester-Degrading Strain

摘要:

以邻苯二甲酸二丁酯（DBP）为唯一碳源，筛选得到一株能够降解DBP的菌株.通过形态学观察、16S rDNA测序及系统发育分析，鉴定该菌株为寡养单胞菌（Stenotrophomonas sp.），命名为B3.首次报道了寡养单胞菌对邻苯二甲酸酯(PAEs)的降解作用.B3可高效降解0.05~50 g?L-1浓度范围的DBP，其中对0.05 g?L-1DBP的降解率为93.4%.经过优化后，在35 ℃、pH 8 条件下对10 g?L-1DBP的降解率为95.8%.反应动力学研究表明，B3降解DBP符合一级降解动力学模型，对50 g?L-1DBP初始降解速率可达1.25 g?L-1?h-1.B3对其他4种常见的PAEs（邻苯二甲酸二（2─乙基己）酯、邻苯二甲酸二甲酯、邻苯二甲酸丁苄酯、邻苯二甲酸二乙酯）和苯胺、甲苯、邻苯二甲酸的降解率均在50%及以上.B3降解PAEs浓度范围宽、底物种类范围广，表明B3在PAEs的生物降解中具有良好的应用前景.

关键词:寡养单胞菌; 邻苯二甲酸酯; 邻苯二甲酸二丁酯; 生物降解; 降解动力学

Abstract:

With dibutyl phthalate (DBP) as the sole carbon source, we isolated a DBPdegrading strain; by its morphology as well as 16S rDNA sequencing and phylogenetic analysis, the strain was identified as Stenotrophomonas sp., designated as strain B3. Degradation of Phthalate esters (PAEs) by Stenotrophomonas was reported for the first time. The degradation efficiency of 0.05 g?L-1 DBP is 93.4%;B3 could efficiently degrade DBP up to 50 g?L-1,and under the conditions of pH 8, 35 ℃, the degradation efficiency of 10 g?L-1 DBP by B3 reached 95.8%. Kinetic studies showed that DBP degradation by B3 followed first-order kinetics, and the initial degradation rate of 50 g?L-1 DBP can reach 1.25 g?L-1?h-1. The degradation efficiencies of four other common PAEs（di-2-ethylhexylPhthalate、dimethyl phthalate、benzyl butyl phthalate、diethyl phthalate）as well as aniline, toluene and phthalic acid by B3 were 50% or higher, suggesting that B3 had a broad substrate spectrum. The ability of B3 to degrade various PAEs at high concentrations indicates that B3 is promising in bioremediation of PAEs.

Key words:Stenotrophomonas; phthalate esters; dibutyl phthalate; biodegradation; kinetics