Ehis-Eriakha Chioma Bertha, Chikere Chioma Blaise, Akaranta Onyewuchi, Akemu Stephen Eromosele
Department of Microbiology, Edo State University Uzairue, Uzairue, Edo State, Nigeria.
World Bank Centre of Excellence, Centre for Oilfield Chemicals and Research, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria.
Braz J Microbiol. 2025 Mar;56(1):203-224. doi: 10.1007/s42770-024-01556-y. Epub 2024 Nov 27.
Polycyclic aromatic hydrocarbons (PAHs) pose severe environmental and public health risks due to their harmful and persistent nature. Therefore, developing sustainable and effective methods for PAH remediation is crucial. This study explores the biostimulation potential of various nutrient supplements in enhancing the metabolic activities of indigenous oleophilic bacteria to PAH degradation and removal. The physicochemical and microbiological characterization of the soil sample obtained from the aged crude oil spill site prior to bioremediation revealed the presence of PAH and other hydrocarbons, reduced nutrient availability as well as an appreciable population of PAH degrading bacteria such as strains of Pseudomonas, Enterobacter, Kosakonia and Staphylococcus. The polluted soil treatment was conducted in six microcosms representing each nutrient supplement: casmes-CM, cocodust-CCD and osmocote-OSM slow-release fertilizers, NPK 20:10:10, casmes + cow dung - CM + CD and a control (unamended soil). Each pot contained 4 kg of soil spiked with 4% Escravos crude oil to a final concentration of 989 mg/kg of PAH, respectively. All treatments enhanced the activity of the indigenous bacteria to promote PAH removal (> 50%) after 35 days although CM + CD had the highest biostimulation effect (B. E.) of 56% with 71.77% PAH attenuation followed by NPK treatment with B. E. of 54.9% and 70.4% PAH removal, respectively. The order of degradation of PAHs from lowest to highest is: control > casmes > osmocote > cocodust > NPK > CM + CD. First-order kinetic model revealed soil microcosm amended with CM + CD had a higher k value (0.0342 day-1) and lower t½ (18.48 day) and this was relatively followed by NPK treated soil. Biostimulation is an effective bioremediation approach to PAH degradation, however, a combined nutrient regimen in the presence of PAH-degrading microbes is more potent and eco-friendly in driving this process.
多环芳烃（PAHs）由于其有害和持久的性质，对环境和公众健康构成严重风险。因此，开发可持续且有效的PAH修复方法至关重要。本研究探讨了各种营养补充剂在增强本地嗜油细菌对PAH降解和去除的代谢活性方面的生物刺激潜力。在生物修复之前，对从老化原油泄漏现场采集的土壤样本进行的物理化学和微生物学表征显示，存在PAH和其他碳氢化合物，养分有效性降低，以及大量PAH降解细菌，如假单胞菌属、肠杆菌属、科萨科尼亚菌属和葡萄球菌属的菌株。在六个代表每种营养补充剂的微观世界中进行了污染土壤处理：酪蛋白胨-酪蛋白胨培养基（CM）、椰糠-椰糠尘（CCD）和奥绿肥-奥绿肥缓释肥料（OSM）、NPK 20:10:10、酪蛋白胨+牛粪 - CM + CD以及一个对照（未改良土壤）。每个花盆装有4千克分别添加4%埃斯克拉沃斯原油的土壤，使PAH的最终浓度达到989毫克/千克。尽管CM + CD具有最高的生物刺激效果（B.E.），为56%，PAH衰减率为71.77%，其次是NPK处理，B.E.为54.9%，PAH去除率为70.4%，但所有处理在35天后均增强了本地细菌促进PAH去除的活性（>50%）。PAHs降解从低到高的顺序为：对照>酪蛋白胨>奥绿肥>椰糠> NPK> CM + CD。一级动力学模型显示，用CM + CD改良的土壤微观世界具有更高的k值（0.0342天-1）和更低的半衰期（t½）（18.48天），NPK处理的土壤相对次之。生物刺激是一种有效的PAH降解生物修复方法，然而，在存在PAH降解微生物的情况下，联合营养方案在推动这一过程方面更有效且生态友好。
