Laboratoire des Bioprocédés Environnementaux, Pôle d'Excellence Régional AUF (PER-LBPE), Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisie.
J Appl Microbiol. 2011 Sep;111(3):525-36. doi: 10.1111/j.1365-2672.2011.05071.x. Epub 2011 Jul 4.
To study the bacterial diversity associated with hydrocarbon biodegradation potentiality and biosurfactant production of Tunisian oilfields bacteria.
Eight Tunisian hydrocarbonoclastic oilfields bacteria have been isolated and selected for further characterization studies. Phylogenetic analysis revealed that three thermophilic strains belonged to the genera Geobacillus, Bacillus and Brevibacillus, and that five mesophilic strains belonged to the genera Pseudomonas, Lysinibacillus, Achromobacter and Halomonas. The bacterial strains were cultivated on crude oil as sole carbon and energy sources, in the presence of different NaCl concentrations (1, 5 and 10%, w/v), and at 37 or 55°C. The hydrocarbon biodegradation potential of each strain was quantified by GC-MS. Strain C450R, phylogenetically related to the species Pseudomonas aeruginosa, showed the maximum crude oil degradation potentiality. During the growth of strain C450R on crude oil (2%, v/v), the emulsifying activity (E24) and glycoside content increased and reached values of 77 and 1.33 g l(-1), respectively. In addition, the surface tension (ST) decreased from 68 to 35.1 mN m(-1), suggesting the production of a rhamnolipid biosurfactant. Crude biosurfactant had been partially purified and characterized. It showed interest stability against temperature and salinity increasing and important emulsifying activity against oils and hydrocarbons.
The results of this study showed the presence of diverse aerobic bacteria in Tunisian oilfields including mesophilic, thermophilic and halotolerant strains with interesting aliphatic hydrocarbon degradation potentiality, mainly for the most biosurfactant produced strains.
It may be suggested that the bacterial isolates are suitable candidates for practical field application for effective in situ bioremediation of hydrocarbon-contaminated sites.
研究与突尼斯油田细菌烃类生物降解潜力和生物表面活性剂生产相关的细菌多样性。
从 8 株突尼斯烃类降解菌中分离并选择了一些细菌进行进一步的特征研究。系统发育分析表明，3 株嗜热菌株属于芽孢杆菌属、芽孢杆菌属和短芽孢杆菌属，5 株中温菌株属于假单胞菌属、溶杆菌属、无色杆菌属和盐单胞菌属。在不同 NaCl 浓度（1、5 和 10%，w/v）和 37 或 55°C 下，将细菌菌株在原油作为唯一碳源和能源的条件下进行培养。通过 GC-MS 定量测定了每株菌的烃类生物降解潜力。与铜绿假单胞菌亲缘关系密切的菌株 C450R 表现出最大的原油降解潜力。在菌株 C450R 生长于原油（2%，v/v）的过程中，乳化活性（E24）和糖苷含量增加，分别达到 77 和 1.33 g l(-1)。此外，表面张力（ST）从 68 降至 35.1 mN m(-1)，表明产生了鼠李糖脂生物表面活性剂。对粗生物表面活性剂进行了部分纯化和特性分析。它具有耐温、耐盐性，对油和烃类具有重要的乳化活性，表现出很大的应用潜力。
本研究结果表明，突尼斯油田中存在多种好氧细菌，包括中温、嗜热和耐盐细菌，具有很强的烃类降解潜力，特别是对产生生物表面活性剂的菌株。
可以认为，这些分离的细菌是有效原位修复烃类污染场地的候选生物。
