A Rapid and Economical Method for Separation of Humic Substances and DNA for PCR and Cloning from Soil Samples

A simple, cost effective and rapid method is described for the separation of total community DNA and humic substances from the soil samples for metagenomic studies. This method was based on hot detergent lyses method for isolation of less sheared high molecular DNA from any soil sample followed by gel exclusion chromatography for complete removal of coextracted humic substances. Purity of the DNA samples isolated by this method was confirmed by restriction digestion and by the amplification of 16S rRNA gene. Four highly contaminated soil samples were evaluated by this method and recovery was found to be 12-20 mu g/g of soil with average size > 25kb in 6-7 hrs. This method can be used as a substitute for expensive kits used in rapid separation of DNA and humic substances from the soil samples.