I used a kind of medium containing vegetable oil to induce bacterial protein, then ammonium sulfate fractionation to concentrate the protein. After resuspending the protein in the buffer, oil still remain in the solution. Is it possible to remove vegetable oil as well as ammonium sulfate through a dialysis membrane at 4℃? Or is there a better method?
I don't think you will be able to remove vegetable oil by dialysis, unless you dissolve it with a dialyzable detergent, such as CHAPS.
It might be easier and faster to centrifuge the sample. The oil should end up floating on top, and you can then draw it off with a syringe or narrow-bore transfer pipette.
Yu Wen Cheng,
I also believe centrifugation will be a good way to separate oils from a sample. That is one way how we separate oils/fats from milk samples too. Agree with Prof. Adam B Shapiro.
Thank you,
Amal.
Thank Adam B Shapiro and Amal Senevirathne for your suggestions. : )
I have tried centrifugation, but the effect is not good and it easily causes protein loss.
When it comes to dialyzable detergent, I have added Triton X-100 to the concentrated protein. Would it be a good way to use a dialysate containing Triton X-100?
and keep it at a temperature where the oil will not solidify (range between 8~10℃) to avoid protein inactivation.
Triton X-100 forms large micelles that are difficult to remove by dialysis. You can use Bio-Beads instead to remove the detergent. I don't know what happens to the oil in this scenario. Maybe you can use Bio-Beads to remove the oil without employing detergent.
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