Method for total microbial DNA purification from humic substances rich soils and sediments.

Abstract

This invention relates to DNA extraction methods from soil and sediments with high humic substances content. The method focuses on the soil preparation phase; removing salts and cations with two different Tris-EDTA (TE) buffers, followed by precipitating humic substances with aluminum hydroxide solution and washing again with TE and cell lysis phase; urea is used as denaturing agents for the cell lysis phase and protein degradation phase while preventing the rediffusion of humic substances with CTAB. The purification can be performed following both the classic phenol chloroform method and using commercial DNA purification columns. This method is very accessible with operation time varying from 1h40 min to 2h30 min. The invention involves the use of TE and aluminum hydroxide solutions for soil preparation, and urea and CTAB as denaturing agents during cell lysis, in the specified concentrations, order, and incubation time, to prevent contamination of final DNA with humic substances