Biosurfactants offer numerous advantages over the chemical surfactants, especially in energy and environment-related applications. Microbial enhanced oil recovery (MEOR) is a technique to recover oil from reservoirs by using microbes and their metabolites. In present study, total sixteen morphologically distinct bacterial strains isolated from different salty areas of the district Khairpur Mir's, Pakistan, were investigated for their MEOR potential. Screening assays for thermotolerance and halotolerance declared 7 out of 16 (43.75%) bacterial isolates as thermotolerant (capable of growing in the temperature range 60-70 °C) and halotolerant (tolerating NaCl concentrations up to 17%, w/v). Moreover, five of them were screened as biosurfactant producers. Among, the lowest surface tension reduction was achieved with biosurfactants produced by the strains KJ2MO (27.8 mN/m) and KJ2SK (29.3 mN/m). The biosurfactant activity was found stable at temperature (100-121 °C, 1 h) and pH (4-10). Moreover, maximum oil recovery was obtained with biosurfactant of bacterial strain KJ2MO (54.7%, 51.25%) followed by KJ2SK (44.7%, 40.5%), KJ1WB (37%, 35.5%) and KJ2MD (37.8%, 31.9%) by using either techniques, i.e., soil washing and sand-packed column, respectively. Moreover, the potent species were identified as Pseudomonas pseudoalcaligenes KJ1WB, Bacillus aerius KJ2MD, Bacillus licheniformis KJ2SK, and Bacillus subtilis KJ2MO using 16S rRNA ribo-typing. The investigated species were found to be promising biosurfactants producers having potential for enhanced oil recovery and could be used in other environmental applications like bioremediation.

中文翻译：

---

使用土壤洗涤和填砂玻璃柱技术通过潜在的生产生物表面活性剂的耐卤细菌提高石油采收率

与化学表面活性剂相比，生物表面活性剂具有许多优势，尤其是在能源和环境相关应用中。微生物提高采油率 (MEOR) 是一种利用微生物及其代谢物从油藏中采油的技术。在本研究中，研究了从巴基斯坦 Khairpur Mir's 区不同盐分地区分离出的总共 16 种形态不同的细菌菌株的 MEOR 潜力。耐热性和耐盐性筛选试验宣布 16 种 (43.75%) 细菌分离株中有 7 种具有耐热性（能够在 60-70 °C 的温度范围内生长）和耐盐性（耐受 NaCl 浓度高达 17%，w/v）。此外，其中五个被筛选为生物表面活性剂生产商。之中，由菌株 KJ2MO (27.8 mN/m) 和 KJ2SK (29.3 mN/m) 产生的生物表面活性剂实现了最低的表面张力降低。发现生物表面活性剂活性在温度 (100-121 °C, 1 h) 和 pH (4-10) 下是稳定的。此外，细菌菌株 KJ2MO (54.7%, 51.25%) 的生物表面活性剂获得最大石油采收率，其次是 KJ2SK (44.7%, 40.5%)、KJ1WB (37%, 35.5%) 和 KJ2MD (37.8%, 31.9%) 通过使用两种技术，即土壤洗涤和填沙柱，分别。此外，利用 16S rRNA 核糖体分型，有效物种被鉴定为假产碱假单胞菌 KJ1WB、Bacillus aerius KJ2MD、Bacillus licheniformis KJ2SK 和 Bacillus subtilis KJ2MO。