Hi!

you can grow the bacteria on a relevant bacteriological grade medium. This will only promote the growth of your bacteria.

The choice of centrifugation speed depends on the size and fragility of the particles in the sample. The smaller the particle size, the higher the centrifugation speed. For example, bacterial cells are pelleted at higher speeds (2000–10,000 x g) than mammalian cells (500–2000 x g). Furthermore, lower centrifugation speeds may be used with more fragile samples.

Hello Sara,

One possible approach could be:

1-Low speed centrifugation (500xg) for 5-10 min to pellet down the human cells while bacteria will primarily remain in suspension.

2-Take the supernantant to another tube and centrifuge for 10 min at 5,000 x g to pellet down bacteria.

3-Remove supernatant and resuspend the bacterial pellet in appropriate volume to start your DNA prep.

Good luck!

Alex

agree with previous answer bacterial cells are pelleted at (2000–10,000 x g) vs mammalian cells (500–2000 x g). Here is also an additional list of speeds for different preps: Blood specimens: To separate blood cells from plasma or serum, centrifuge at 1000–2000 x g for 10–15 minutes.

• Urine specimens: To separate urine sediment from supernatant, centrifuge at 400 x g for 5 minutes.
• Cell culture specimens: To pellet mammalian cells, centrifuge at 500 x g for 5 minutes. To pellet bacterial cells, centrifuge at 5000 x g for 10 minutes.
• Protein specimens: To remove insoluble debris from protein extracts, centrifuge at 10,000–20,000 x g for 10–20 minutes.
• DNA specimens: To pellet DNA from aqueous solutions, centrifuge at 12,000–16,000 x g for 10–20 minutes. To pellet DNA from organic solvents, centrifuge at 20,000 x g for 10 minutes.

https://lab.plygenind.com/centrifuge-speeds-for-different-sample-preparations-a-practical-guide