School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan 316022, Zhejiang.
College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China.
Chemosphere. 2021 Feb;265:129090. doi: 10.1016/j.chemosphere.2020.129090. Epub 2020 Nov 30.
The present study was conducted to enhance the biosurfactant production yield of Pseudomonas sp. CQ2 isolated from the Chongqing oilfield (China). Besides, the capability of biosurfactant and underlying mechanism for remediation of heavy metal contaminated soil was also investigated. Our results suggested that maximum biosurfactant production (40.7 g/L) was attained at 35 °C by using soybean oil and ammonium nitrate as carbon and nitrogen sources with pH 7, rotational speed of 175 rpm and inoculation ratio of 3%). The removal efficiencies of 78.7, 65.7 and 56.9% for Cd, Cu and Pb respectively were achieved at optimized bioleaching conditions (pH: 11, soil/solution ratio: 30:1 and non-sterilized soil), comparative tests between common chemical surfactants (SDS, Tween-80) and biosurfactants demonstrated the larger removal capacity of biosurfactants. Through SEM-EDX, it was found that the granular material disappeared, the content of Cd, Cu and Pb decreased significantly, and the soil surface became smooth with hole formation after soil washing following bioleaching. ATR-FTIR results showed that the carboxyl functional groups in biosurfactants could chelate heavy metals. These results indicated that biosurfactants from Pseudomonas sp. CQ2 could effectively eliminate Cd, Cu, and Pb from soil.
本研究旨在提高从中国重庆油田分离的假单胞菌 CQ2 的生物表面活性剂产量。此外，还研究了生物表面活性剂的修复重金属污染土壤的能力及其潜在机制。研究结果表明，在 35°C 下，以大豆油和硝酸铵为碳源和氮源，pH 值为 7，转速为 175rpm，接种率为 3%，可获得最大生物表面活性剂产量（40.7g/L）。在优化的生物浸出条件（pH：11、土壤/溶液比：30:1、未灭菌土壤）下，Cd、Cu 和 Pb 的去除效率分别达到 78.7%、65.7%和 56.9%。与常用化学表面活性剂（SDS、Tween-80）相比，生物表面活性剂对生物浸出前后土壤的去除能力更大。通过 SEM-EDX 发现，颗粒物质消失，Cd、Cu 和 Pb 的含量显著降低，土壤表面变得光滑，形成孔穴。ATR-FTIR 结果表明，生物表面活性剂中的羧基官能团可以螯合重金属。这些结果表明，假单胞菌 CQ2 产生的生物表面活性剂可以有效地从土壤中去除 Cd、Cu 和 Pb。
