[Objective] The quality and efficiency of genomic DNA extraction play a key role in molecular biology research. The cell wall of Gram positive bacterium is thick and hard to be destroyed, which makes it difficult for genomic DNA extraction. The objective of this study was to find an efficient and repeatable method to extract the genomic DNA from Gram positive bacterium. [Methods] The genomic DNA of Clostridium thermocellum and Thermoanaerobacterium thermosaccharolyticum were extracted using six extraction m...