Screening of Degrading Bacteria for Phthalic Acid Esters Under Cadmium Stress and Its Application

镉胁迫下邻苯二甲酸酯降解菌的筛选及其应用研究

In order to enrich the degrading microbial resources for phthalic acid esters(PAEs)under cadmium stress,a degrading bacterium B-7 for di(2-ethylhexyl)phthalate(DEHP)was screened from the strains stored in the laboratory by means of inorganic salt liquid medium containing DEHP and cadmium,and the characteristics of the strain were studied.Strain B-7 was Bacillus amyloliquefaciens,which had high biosafety and excellent degradability to DEHP.The optimum temperature for degradation was 25–40℃,and the optimum pH value was 6–8.Strain B-7 was cultured in inorganic salt medium(MSM)with an initial DEHP concentration of 400 mg/L and cadmium content of 10 mmol/L for 4 d,and its degradation rate of DEHP was up to 93.1%.In addition,the strain had a strong degradation ability to dimethyl phthalate(DMP),diethyl phthalate(DEP),and dibutyl phthalate(DBP).In soil contaminated by cadmium and DEHP,the synergic degradation of B-7 and indigenous microorganisms in soil significantly increased the degradation rate of DEHP,indicating that this strain had potential application value in the field of microbial remediation of soil contaminated by cadmium and PAEs.

为丰富镉胁迫下能高效降解邻苯二甲酸酯的微生物资源,该研究通过含有邻苯二甲酸二(2-乙基己基)酯(DEHP)和镉的无机盐液体培养基从实验室保藏菌株中筛选到1株DEHP高效降解菌B-7,并对菌株特性进行了研究。菌株B-7为解淀粉芽孢杆菌,生物安全性高,对DEHP的降解性能优良,发挥降解作用的最适温度为25~40℃、最适p H值为6~8。菌株B-7在DEHP初始浓度为400 mg/L、镉含量为10 mmol/L的无机盐培养基中培养4 d,其对DEHP的降解率高达93.1%,且该菌株对DMP、DEP、DBP均具有较强的降解能力。在镉和DEHP复合污染的土壤中,B-7与土壤土著微生物的协同降解显著提高了DEHP的降解率,表明该菌株在镉和邻苯二甲酸酯复合污染土壤的微生物修复领域具有潜在应用价值。