DNA extraction from Soil

For All you guys whom dealing with environmental molecular
For All you guys whom dealing with metagenomic world......
Relax....we have to be patient...and keep moving forward


DNA extraction from soil (Zhou et al, 1996)
Advantage: Simple & High DNA Yield......

1. Weigh 5-15 g of soil into 50-mL tube.
2. Add 13.5 mL lysis buffer (100 mM Tris-HCl, 100 mM sodium
EDTA, 100 mM sodium phosphate, 1.5 M NaCl, and 1% CTAB)
plus 100 μL of proteinase K (10 mg/mL). Shake horizontally at
37°C for 30 minutes.
3. Add 1.5 mL of 20% SDS. Incubate at 65°C for 2 hours with
gentle, end-to-end inversion every 15-20 minutes.
4. Spin at 7000 rpm (6000g) for 10 minutes.
5. Transfer supernatant to a clean 50-mL tube.
6. Add 4.5 mL lysis buffer plus 0.5 mL of 20% SDS to soil pellet.
Vortex for 10 seconds.
7. Incubate at 65°C for 10 minutes.
8. Spin at 7000 rpm (6000g) for 10 minutes.
9. Collect supernatant and combine with the supernatant from step5.
10. Repeat steps 6-9 again.
11. Extract the supernatant with equal volume of chloroform/isoamyl
alcohol (24:1 v/v).
12. Spin at 6500 rpm (5500g) for 10 minutes.
13. Collect aqueous (top) phase in a 40-mL Sorvall tube.
14. Precipitate genomic DNA with 0.6 volume of isopropanol at room
temperature for 1 hour or overnight.
15. Spin at 11,600 rpm (16,000g) for 20 minutes.
16. Discard supernatant. Wash DNA pellet with approximately 3 mL
of cold 70% ethanol. Spin at 11,600 rpm (16,000g) for 10
minutes.
17. Air-dry pellet.
18. Resuspend DNA pellet with approximately 150 μL of dH2O.

Ok good luck.......


For Detail please refer to this Article :
Zhou et. al. (1996) DNA Recovery from Soils of Diverse Composition. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. 62(2) : 316–322