Technologies of extraction and purification of microbial total DNA from a meadow soil

In order to select and establish an appropriate method for extracting and purifying the microbial total DNA from a meadow soil, seven extraction methods (five direct methods, one indirect method and one commercial kit method) and two purification methods were examined, with the quantity and quality of extracted and purified total DNA compared. The results showed that all the seven methods could extract the total DNA with a length of approximately 23 kb, among which, the SDS- high salt extraction method was the best. This method has a highest DNA yield, and the purity after purification of the DNA is close to that obtained by using kits, being available in 16S rDNA amplification. Between the two purification methods, the effect of agarose gel electrophoresis plus minicolumn was satisfactory and applicable for the purification of crude DNA from the meadow soil, with most of the purified total DNA being able to be PCR-amplified and meet the requirements of the purity of DNA in the follow-up molecular operations.