Isolation and Purification of Bacterial DNA from Soil

Abstract

DNA-based detection of bacterial populations helps to overcome a major limitation of microbial ecology and soil microbiology; the difficult task of specifically monitoring an individual population of microbes in the environment, and in the presence of the entire microbial community. This chapter presents two alternate strategies for the isolation of total bacterial community DNA from soil samples, the first is based on the fractionation of bacteria from soil prior to lysis while the second involves direct lysis of bacteria in the presence of the soil matrix. The bacterial fractionation method involves the separation of bacterial cells from the bulk of the soil prior to cell lysis and recovery of bacterial community DNA. In the direct lysis method, bacterial cells are lysed directly in the presence of the soil matrix. High temperature, high concentrations of detergent, and mechanical disruption using minute glass beads are employed for cell lysis using this method.