粘质沙雷氏菌TF-1对土壤中氯苯类污染物生物降解及其在场地原位修复中的应用

Serratia marcescens TF-1 for biodegradation of chlorobenzene contaminants in soil and its application in in-situ remediation of chemical industrial sites

摘要:

氯苯类污染物(chlorobenzenes, CBs)对生态环境造成严重威胁，功能菌株在该类污染场地修复中具有重要应用潜力。为深入解析功能菌在CBs原位生物修复中的应用潜力，本研究基于已分离的粘质沙雷氏菌(Serratia marcescens) TF-1，开展了土壤中氯苯(chlorobenzene, CB)和1,2-二氯苯(1, 2-dichlorobenzene, 1,2-DCB)生物转化特性和降解动力学研究，并应用该菌株进行了化工污染场地原位修复试验。批次血清瓶实验结果表明，污染物浓度为20–200 mg/L时，TF-1对CB的降解速率为0.22–0.66 mol/(g_cell·h)，降解过程符合Haldane模型，最佳活性浓度为23.12 mg/L。实验室模拟污染土壤降解结果显示，TF-1与琥珀酸钠(sodium succinate, SS)联合应用可显著提高CBs的降解效果，CB的降解速率常数最高为0.104 d^–1，半衰期为6.66 d；1,2-DCB的降解速率常数最高为0.068 7 d^–1，半衰期为10.087 d。化工污染场地原位修复结果显示，注入菌剂和SS对CBs污染物去除效果显著，10 d后去除率达到84.2%–100%，CB、1,4-二氯苯(1,4-dichlorobenzene, 1,4-DCB)和苯并[a]芘均被完全去除。微生物多样性分析表明原位修复实现了TF-1定殖和土著微生物固氮弧菌属(Azoarcus)的富集，Azoarcus可能在降解中发挥关键作用。本研究为氯苯类污染场地的原位生物修复提供了理论依据和实践经验。

Abstract:

Chlorobenzene contaminants (CBs) pose a threat to the eco-environment, and functional strains hold considerable potential for the remediation of CB-contaminated sites. To deeply explore the application potential of functional bacteria in the in-situ bioremediation of CBs, this study focused on the biodegradation characteristics and degradation kinetics of CB and 1,2-dichlorobenzene (1,2-DCB) in soil by the isolated strain Serratia marcescens TF-1. Additionally, an in-situ remediation trial was conducted with this strain at a chemical industrial site. Batch serum bottle experiments showed that the degradation rate of CB at the concentrations ranging from 20 to 200 mg/L by TF-1 was 0.22-0.66 mol/(g_cell·h), following the Haldane model, with the optimal concentration at 23.12 mg/L. The results from simulated soil degradation experiments indicated that the combined use of TF-1 and sodium succinate (SS) significantly enhanced the degradation of CBs, with the maximum degradation rate of CB reaching 0.104 d^-1 and a half-life of 6.66 d. For 1,2-DCB, the maximum degradation rate constant was 0.068 7 d^-1, with a half-life of 10.087 d. The in-situ remediation results at the chemically contaminated site demonstrated that the introduction of bacterial inoculant and SS significantly improved the removal of CBs, achieving the removal rates of 84.2%-100% after 10 d. CB, 1,4-dichlorobenzene (1,4-DCB), and benzo[a]pyrene were completely removed. Microbial diversity analysis revealed that the in-situ remediation facilitated the colonization of TF-1 and the enrichment of indigenous nitrogen-fixing Azoarcus, which may have played a key role in the degradation process. This study provides a theoretical basis and practical experience for the in situ bioremediation of CBs-contaminated sites.