Dataset

Bioremediation of crude-oil-contaminated soils is critical to supporting soil ecosystem health and functioning. Here, to explore the potential for different remediation strategies to restore soil microbial functioning and enhance remediation, three strains of bacteria, <i>Bacillus toyonensis</i>, <i>Bacillus</i> sp. and <i>Bacillus cereus,</i> were inoculated to saline crude oil-contaminated soil collected from Azadegan Oil Field, Iran. Bacteria were added using different carriers, including corn biochar, humic acid, chitosan and kaolin, and free bacteria as a control. Changes in soil metal concentrations and residual crude oil were determined after 60 days of incubation. Soil respiration, microbial biomass, and enzyme (dehydrogenase and catalase) activities were measured. The carriers accompanying a bacterial consortium were more efficient than free bacteria in removing crude oil and heavy metals from soil, and they performed better in removing n-alkanes with carbon chains of C12–24. The oil removal rate and metal immobilization efficiencies were greatest in soils with chitosan+bacteria treatment, with removal of crude oil, Al, Pb, Sr and Cr at 93%, 63%, 37%, 54% and 15%, respectively, compared to without any treatments and 61%, 54%, 9%, 50% and 3%, respectively, compared to free cells. Soil electrical conductivity decreased after application of bacterial mixtures with and without carriers. The inoculation of bacteria and the application of soil amendments increased soil microbial biomass carbon and the activity of catalase and dehydrogenase. Overall, our results indicated the greatest potential remediation was achieved by applying immobilized microorganisms in chitosan to accelerate the biodegradation of crude oil and the removal of heavy metals.

原油污染土壤的生物修复对于维持土壤生态系统健康与生态功能至关重要。本研究为探究不同修复策略恢复土壤微生物功能、强化修复效果的潜力，将3株细菌——托永芽孢杆菌（Bacillus toyonensis）、芽孢杆菌属未定种（Bacillus sp.）及蜡样芽孢杆菌（Bacillus cereus）接种自伊朗阿扎德干油田（Azadegan Oil Field）采集的含盐原油污染土壤中。实验采用不同载体负载细菌：包括玉米生物炭、腐殖酸、壳聚糖与高岭土，并设置游离细菌组作为对照。培养60天后，测定土壤金属浓度与残留原油的变化，并检测土壤呼吸强度、微生物生物量及脱氢酶、过氧化氢酶两种酶的活性。负载细菌联合体的载体组在去除土壤中原油与重金属方面的效率优于游离细菌组，且对碳链长度为C12~C24的正构烷烃的降解效果更佳。壳聚糖+细菌处理组的原油去除率与重金属固定效率最高：与未处理组相比，该组对原油、铝（Al）、铅（Pb）、锶（Sr）及铬（Cr）的去除率分别为93%、63%、37%、54%和15%；与游离细菌组相比，对应去除率分别为61%、54%、9%、50%和3%。施用负载或未负载载体的细菌混合物后，土壤电导率均有所下降。细菌接种与土壤改良剂的施用均提升了土壤微生物生物量碳含量，以及过氧化氢酶与脱氢酶的活性。综上，本研究结果表明，采用壳聚糖负载固定化微生物的修复策略可加速原油生物降解与重金属去除，是本次实验中效果最优的修复方案。