Help me with pressure and busting cells?

January 28, 2009 2:11 PM

Nerdy-science-geek question: What kind of pressure am I looking for if I want to bust algae cell walls by sending a algae-concentrated liquid through a small aperture? I mean, behind the aperture, size of aperture, etc....knowing that the sudden reduction in pressure *should* bust things up. Any thoughts? Of course, I am wondering about doing this in terms of what I've read, and may experiment with in future, but don't have firsthand knowledge of. Thanks in advance!
posted by Kickstart70 to science & nature (12 comments total)

The traditional piece of equipment for doing this is a French cell press. The pressures in a cell press are big. On the order of tens of thousands of psi.
posted by mr_roboto at 2:42 PM on January 28

This patent claims, in part, "passing the aqueous suspension [including algae cells] through a constriction into a liquid phase at a pressure drop ranging from about 50 to 200 psig to rupture the cells." It may be worth reading the rest of the patent.

I reckon that, in addition to the factors you identified, the species, health, etc. of the algae will play a role in the requirements.
posted by exogenous at 2:43 PM on January 28

Ah, excellent. Glad to see that what I (a complete layman) was thinking was already covered. Now I wonder what's possible on my home workbench (without causing me injury, of course).

Now, as I understand it, the venturi (the aperture) multiplies the pressure effect, so I can work up something using small amounts of liquid and a tiny venturi, I should be able to reach some very high pressures.
posted by Kickstart70 at 3:03 PM on January 28

I guess my question is, what are you trying to accomplish?

Do you need to lys every last one of them or would most of them be ok?

Is this a "I have to do a sample once a week" kind of operation, or is this a "We're trying to get the little bastards out of our fish tank" situation where you want it to run constantly?
posted by Kid Charlemagne at 3:03 PM on January 28

Really this is more proof-of-concept for my own interest than anything else....I'm curious about extracting oil from algae. For this, I need to break up the cells, then I basically figured a simple heating and cooling cycle would allow the oil to separate and be siphoned off. Of course, for this more breaking up is better, but any reasonable percentage would be just fine.

To be clear, I'm not looking at any sort of large scale production, running my car on algae oil, or anything like that. I just want to play and discover.
posted by Kickstart70 at 3:14 PM on January 28

To get stuff out of cells, the easiest way to do it is to boil them.

Other ways to lyse cells: detergents or using osmolarity gradients (which might not work on algae).
posted by porpoise at 3:38 PM on January 28

Is this for a fish tank? Will there be any other side effects like damaging bacterium?
posted by Area Control at 3:44 PM on January 28

I'd heat them, lyse them with a high salt concentration, or force them through a super fine gauge syringe several times and see what works best. Detergents will likely work well, but may interfere with the lipids you want to play with.
posted by Science! at 4:13 PM on January 28

In addition to a French Press, a Microfluidizer works this way also. The pressures involved are very high, something like 10-20 thousand psi. The microfluidizer uses an air piston with 170 psi air on a 12" diameter piston connected to a 1" diameter piston that drives the cell slurry through the orifice. The diameter ratio of the pistons gives you ~144-fold pressure increase on the slurry side, and the orifice you drive the slurry through is 75-100 um in diameter. It's probably tricky to homebrew such a system.

My guess is that algae are difficult to lyse - I'm imagining they have tough cell walls like plants or fungi (I have experience with yeast lysis, and things like the microfluidizer don't work so well for that).

Other options to consider are bead-beating (basically grinding with beads), grinding under liquid nitrogen, or sonication.

Useful search terms: algae cell disruption, algae cell lysis.
posted by pombe at 4:23 PM on January 28

I'd heat them, lyse them with a high salt concentration, or force them through a super fine gauge syringe several times
This is very unlikely to succeed.

You need a French cell press or a homogenizer (no pressure).

What do you need the algae for and why do you want to do it with pressure?
posted by yoyo_nyc at 5:33 PM on January 28

Boiling might work, but if you're trying to isolate an oily component, it might vaporize away or be degraded by the heat.

Depending on how much stuff you're trying to get out, and what you want to do with it afterward, just extracting your algae culture with an organic solvent might work.
posted by Sublimity at 1:46 PM on January 29

Hey Kickstart - instructables just had a short piece on algae bioreactors...
posted by porpoise at 7:42 AM on February 5