THE MICROBIAL COMMUNITY OF THE ISOLATES FROM THE TALU SANDSTONE IN THE MIAOLI AREA IN TAIWAN

Deep subsurface bacteria may affect the geochemical and biochemical conditions in geological formation and can utilize crude oil for carbon source, and thus deteriorate the oil quality. Based on that, we must understand the physiological characteristics and microbial community of these deep subsurface bacteria.

The samples of this study taken from the 3385-meter-deep subsurface rocks (i.e. Talu Sandstone) and drilling mud were collected from an oil-drilling well in the Miaoli area in Taiwan. The indigenous bacteria from these rocks and mud were isolated and cultured. The bacteria were isolated by using the molecular biotechnology such as DNA extraction and purification, PCR, gel electrophoresis, RFLP (restriction fragment length polymorphism), gene sequencing, and phylogenetic relationship.

17 bacterial strains were isolated in this study from 5 different depths in an oil-drilling well. The bacterial isolates were identified as the genera of Cellulomonas and Pseudomonas, which are divided into two groups. The first group, Genus Cellulomonas was distributed in the subsurface area that was located in 400 meters depth below the surface; the another group Genus of Pseudomonas was distributed in the area that was ranged from 400 to 3500 meters depth below the surface. The experimental results of physiological characteristics for these deep subsurface strains in this study revealed that the conditions in temperature, pH, and salinity for bacterial growth were determined to be in the range of 20-40 degree C, pH 6-12, and 1.5-6%, respectively.