[Comparison of the methods for extracting and purifying microbial total DNA from an aeolian sandy soil]

In order to select and establish an appropriate method for extracting and purifying the microbial total DNA from an aeolian sandy soil, six extraction methods (five direct methods and one indirect method) and two purification methods were examined, with the quantity and quality of extracted and purified total DNA compared. All the six extraction methods could extract the total DNA with a length of approximately 23 kb, among which, the improved SDS high salt extraction method (using 40% PEG8000 and 4 mol x L(-1) NaCl to precipitate DNA) was the best. This method could have a yield slightly less than that obtained by using kits, and the extracted DNA had the highest purity after purification, being available in 16S rDNA PCR amplification. Among the purification methods, the effect of agarose gel electrophoresis plus minicolumn was satisfactory, 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.