Growth and metabolism of an aerobic thermophilic Geobacillus strain under simulated composite extreme reservoir conditions

Abstract

The growth and metabolism of an aerobic thermophilic Geobacillus strain DM-2 under simulated composite extreme conditions of the Ng3, Gudao Block, Shengli Oilfield (China) with sufficient oxygen and nutrition were investigated. The experimental device for simultaneously simulating the temperature, pressure, salinity, porosity, permeability, fluid characteristics and development status of the target reservoir was designed, where the air assisted flooding technology was used. Particularly, the oxygen demand was estimated according to biotic and abiotic oxygen consumption. Despite the relatively lower rates of microbial growth and metabolism, the strain was able to grow under these conditions with the cell density increased from 106 to 108 cellsmL−1, and CH3COO− produced at the concentration of about 400 mg ⋅ L−1. Aerobic microorganisms, such as Geobacillus sp., may be promising candidates for microbial enhanced oil recovery and oily sewage treatment technology.