Al-Otibi Fatimah, Al-Zahrani Rasha M, Marraiki Najat
Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 22452, Riyadh 11495, Saudi Arabia.
J Fungi (Basel). 2023 Feb 6;9(2):216. doi: 10.3390/jof9020216.
Microbial biodegradation of oil-hydrocarbons is one of the sustainable and cost-effective methods to remove petroleum spills from contaminated environments. The current study aimed to investigate the biodegradation abilities of three isolates from oil reservoirs in Saudi Arabia. The novelty of the current work is that the biodegradation ability of these isolates was never tested against some natural hydrocarbons of variable compositions, such as Crude oil, and those of known components such as kerosene and diesel oils.
The isolates were treated with five selected hydrocarbons. The hydrocarbon tolerance test in solid and liquid media was performed. The scanning electron microscope (SEM) investigated the morphological changes of treated fungi. 2, 6-Dichlorophenol Indophenol (DCPIP), drop collapse, emulsification activity, and oil Spreading assays investigated the biodegradation ability. The amount of produced biosurfactants was measured, and their safety profile was estimated by the germination assay of tomato seeds.
The tolerance test showed enhanced fungal growth of all isolates, whereas the highest dose inhibition response (DIR) was 77% for treated with the used oil ( 0.05). SEM showed morphological changes in all isolates. DCPIP results showed that used oil had the highest biodegradation by and Mixed oil induced the highest effect in oil spreading, drop collapse, and emulsification assay caused by . The highest recovery of biosurfactants was obtained by the solvent extraction method for (4.6 g/L), (4.22 g/L), and (3.73 g/L). The biosurfactants produced by the three isolates stimulated tomato seeds' germination more than in control experiments.
The current study suggested the possible oil-biodegradation activities induced by three isolates from Riyadh, Saudi Arabia. The produced biosurfactants are not toxic against tomato seed germination, emphasizing their environmental sustainability. Further studies are required to investigate the mechanism of biodegradation activities and the chemical composition of the biosurfactants produced by these species.
微生物对石油烃的生物降解是从受污染环境中去除石油泄漏的可持续且经济高效的方法之一。当前研究旨在调查从沙特阿拉伯油藏中分离出的三株菌的生物降解能力。当前工作的新颖之处在于，从未针对某些成分可变的天然烃（如原油）以及煤油和柴油等已知成分的烃测试过这些分离株的生物降解能力。
用五种选定的烃处理分离株。在固体和液体培养基中进行烃耐受性测试。扫描电子显微镜（SEM）研究处理过的真菌的形态变化。采用2,6 - 二氯酚靛酚（DCPIP）、液滴塌陷、乳化活性和油扩散试验研究生物降解能力。测量产生的生物表面活性剂的量，并通过番茄种子发芽试验评估其安全性。
耐受性测试表明所有分离株的真菌生长均增强，而在用废油处理（0.05）时最高剂量抑制反应（DIR）为77%。扫描电子显微镜显示所有分离株均有形态变化。DCPIP结果表明，废油的生物降解率最高， 和 混合油在由 引起的油扩散、液滴塌陷和乳化试验中诱导的效果最高。通过溶剂萃取法获得的生物表面活性剂回收率最高， 为（4.6 g/L）， 为（4.22 g/L）， 为（3.73 g/L）。这三株分离株产生的生物表面活性剂比对照实验更能刺激番茄种子发芽。
当前研究表明，来自沙特阿拉伯利雅得的三株 分离株可能具有油生物降解活性。产生的生物表面活性剂对番茄种子发芽无毒，强调了它们的环境可持续性。需要进一步研究来调查生物降解活性的机制以及这些物种产生的生物表面活性剂的化学成分。
