Department of Biology, College of Science, Sultan Qaboos University, Muscat, Oman.
Department of Petroleum and Chemical Engineering, College of Engineering, Sultan Qaboos University, Muscat, Oman.
Appl Microbiol Biotechnol. 2021 Jan;105(1):105-117. doi: 10.1007/s00253-020-11015-x. Epub 2020 Nov 20.
The world economy depends heavily on crude oil. With a conventional oil recovery process, only one-third of crude oil is extracted. Various technologies have been developed to maximize the recovery of oil resources from natural reservoirs. Polymer technology has been used in many oil fields around the world. The biopolymer pullulan, produced by some Aureobasidium species, has been used in many industrial applications, but no research has been conducted regarding its use in the microbial enhancement of oil recovery (MEOR). Here, we investigate the potential of pullulan produced by newly isolated species Aureobasidium mangrovei SARA-138H for enhancement of oil recovery. Our results indicate that under optimized conditions, that is, sucrose as the carbon source in the medium, a pH of 9, incubation at 25 °C, and 250 rpm agitation, the fungus was able to produce 10 g/L of pullulan. The maximum viscosity achieved under these conditions was 318 cP after 15 days of incubation. Pullulan solution (10 g/L) showed the ability to recover 36.7% of heavy crude oil after 34.2% of secondary oil recovery. However, diluted pullulan in brine at the ratio (1:1) resulted in the recovery of 20.23% of oil from the residual oil in the core after 22.6% of secondary oil recovery. A 20-day injectivity test revealed that pullulan passed smoothly through the core, causing no blockage. It was concluded that pullulan from A. mangrovei SARA-138H was able to increase oil recovery to a degree comparable to that achieved with many polymers used in oil fields around the world. KEY POINTS: • First report of biopolymer "pullulan" from A. mangrovie. • Optimum conditions for pullulan production were obtained. • Pullulan recovered 36.7% of heavy oil from residual oil in place, with good injectivity.
世界经济在很大程度上依赖于原油。在常规的采油过程中，只有三分之一的原油被开采出来。为了最大限度地从天然储层中回收石油资源，已经开发了各种技术。聚合物技术已在世界各地的许多油田得到应用。某些金孢子菌属产生的生物聚合物普鲁兰已在许多工业应用中得到应用，但尚未研究其在微生物强化采油（MEOR）中的应用。在这里，我们研究了新分离的红树林金孢子菌 SARA-138H 产生的普鲁兰在提高采油率方面的潜力。我们的结果表明，在优化条件下，即在培养基中使用蔗糖作为碳源、pH 值为 9、在 25°C 下孵育、以 250 rpm 的速度搅拌，真菌能够产生 10 g/L 的普鲁兰。在这些条件下，孵育 15 天后达到的最大粘度为 318 cP。普鲁兰溶液（10 g/L）在经过 34.2%的二次采油后，能够回收 36.7%的重质原油。然而，在盐水稀释的普鲁兰在比例（1:1）下，在经过 22.6%的二次采油后，从岩心中的残余油中回收了 20.23%的油。20 天的注入性测试表明，普鲁兰顺利地通过了岩心，没有造成堵塞。研究结果表明，来自红树林金孢子菌 SARA-138H 的普鲁兰能够在一定程度上提高采油率，达到世界许多油田使用的聚合物所达到的水平。要点： • 首次报道了来自 A. mangrovie 的生物聚合物“普鲁兰”。 • 获得了普鲁兰生产的最佳条件。 • 普鲁兰从油藏中的残余油中回收了 36.7%的重油，具有良好的注入性。
