Stool DNA Extraction Guide | Microbial & Host DNA Purification

Add 0.2 g of stool sample and 600 µL of L buffer to the bead tube, then vortex until thoroughly dispersed. Add 100 µL of L enhancer and briefly vortex again.

Incubate the sample at 65°C for 10 minutes, then homogenize by bead beating for 10 minutes at maximum vortex mixer speed to disrupt microbial cell walls.

Centrifuge at 14,000 g for 5 minutes and transfer up to 400 µL of supernatant to a clean tube. Add 250 µL of cleanup buffer and vortex to remove inhibitors like bile, humic acids, and food debris.

Centrifuge the cleanup mixture at 14,000 g for 2 minutes and transfer up to 500 µL of supernatant to a clean tube. Add 900 µL of binding buffer, vortex briefly, then load 700 µL into a spin column and centrifuge.

Place the spin column in a clean collection tube, add 500 µL of wash buffer, and centrifuge for 1 minute. Discard the flow-through and centrifuge again for 30 seconds to remove residual wash buffer.

Place the spin column in a clean tube, add 100 µL of elution buffer, and leave at room temperature for 1 minute. Centrifuge for 1 minute at 14,000 g and discard the column.

The purified DNA in the collection tube is ready for immediate use or long-term storage at appropriate conditions.