Question

What is the required centrifugal force to precipitate random bacteria in a sludge sample?


I'm trying to find out at which rotational speed all the bacteria will be gone. Already tried up to 20.000 x g but there still seem to be some bacteria left. So is there something like a standard rotational speed where every (or at least most) bacteria will precipitate?

Answer 1

ummm...to pellet out the cells we used d speed of 10000 rpm....we had done it for ecoli cells....i dnt know about the exact centrifugal force....hope this helps:)

Answer 2

Well the unit rpm is not useful since the conversion factor to g is different for every centrifuge. There might be some species that doesn't precipitate even at 20k g. Guess I'll have to find out the required force for all possible present bacteria individually.
These are:
- Vibrio parahaemolyticus
- Pseudomonas luteola
- Aeromonas hydrophila/caviae
- Peptostreptococcus spp
- Clostridium spp

Does anyone have some info about the required force to pellet out those species? Or maybe the samples need to be in the centrifuge for a longer time? I'm currently using 5 minutes.

Answer 3

ohhh...umm...i need 2 check dis...

Answer 4

hey i tried to find out...i got this
I've pelleted bacterial cells at 3000 x g with no problem, but it takes 5-10 minutes, depending on the cell density. If you're pressed for time, you can do a high speed (> 8000 x g) spin for about 2 minutes. Just remember that you might want to spin at 4C, depending on what your downstream application is (enzymatic assays, nucleic acid extraction, etc).

Answer 5

Still in need of some source like an article where this is researched.
I searched everywhere but can't find something useful.