Yeast-Powered Fuel Cell Feeds On Human Blood

holy_calamity writes "Canadian researchers have taken a sensible, if slightly creepy, step towards solving the problem of medical implant batteries running down. They've built a fuel cell powered by yeast that feed on the glucose in human blood. If this makes it into people, keeping your implants going will be as simple as eating a donut."

Re:Waste

[Evanisincontrol]

For instance, to keep the yeast cells healthy, their waste products will need to be removed without allowing any harmful substances to leach out into the blood stream. "I think people will figure this out. This is a first step," he says.

I'm a bit concerned about this problem. Would this necessitate the installation of a shunt or some other extraction point for the waste? Seems like a fairly significant barrier to me. If you have to perform regular extractions (or worse, operations) is it really better than the current alternatives?

Isn't the waste product of yeast alcohol? As long as the waste is a low amount, it sounds like this would have the same effect as drinking alcohol (which the body is quite capable of disposing of). If it's not a low amount... well, at least the patient dies happy!

Re:If its not april Fools

[Cube Steak]

The yeast they are talking about here is not Candida albicans which is the strain that causes yeast infection. In this they are most likely talking about Saccharomyces cerevisiae which is just ordinary brewers yeast and is harmless. Do you really think they would be dumb enough to stick a known pathogen in someone's body?

Re:Hey now.

[shadowbearer]

Read the FA, especially linked journal summary, published back in December.

http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=4671110 [ieee.org]

  This isn't an April Fools joke.

  This is brilliant. There's been a lot of scifi stories that hypothesized implants that run off of neural impulses; this isn't limited by the extremely small amounts of electricity that the nervous system generates.

  Waste is definitely going to be a problem, but one that's likely solvable by engineering yeast that produce waste that can be metabolized and flushed out by the liver or kidneys.

  This may also be an answer to the problem of powering nanomachines that repair the human body. I'm hardly an expert in the field, anyone who is (and is still here today) care to comment?

SB

Re:Awesome idea, but..

[Cube Steak]

Saccharomyces cerevisiae, or brewer's yeast, which is what they are using doesn't cause yeast infections. You are thinking of the pathogenic strain Candida albicans.

Re:If its not april Fools

[TinBromide]

If the implant is to be more useful than a battery, it needs to last longer than the lifespan of a single yeast cell. In order for that to happen, the yeast needs to be able to reproduce inside the body. Chances are, they'll work out a way for the immune system to not attack the blood/yeast barrier (rejection is bad) or get them to not attack the yeast itself through immune system suppression drugs. If the yeast can live, reproduce, and produce waste products in blood (or what diffuses across the barrier) in the implant, it might be able to do that outside the implant.

Sounds like they're taking a non-pathogen and turning it into something that can survive and reproduce in the body. Whether or not it thrives once it gets there remains to be seen. It might not put out enough waste that its immediately noticable, but what happens if this gets loose in someone with a weak immune system? They might ferment to death.

Re:Hey now.

[Zakabog]

This isn't an April Fools joke.

That was the parent's point.

"We need to keep this site as useless as possible today. You're not helping."

"Legitimate news?" wasn't questioning the legitimacy of the article, it was questioning why there was legitimate news today.

Re:Waste

[Anonymous Coward]

Yeast only produce alcohol when there's isn't any oxygen available.

Re:Waste

[Ironica]

But what if the person is a diabetic, or pre-diabetic, and consumes no non-organic sugars or wheat? There would be minimal sugar-yeast in their body.

Huh?

Are you saying that people who don't consume refined sugar or carbs don't have glucose in their bloodstream? Or that this invention would somehow rely on the body's supply of yeast to run?

We all have glucose in our blood, even diabetics. The issue for them is that the insulin system, which keeps blood glucose levels steady in spite of rapidly changing intake, isn't working properly... so they have to keep their intake of sugars and carbs low. There's still plenty of glucose.

The invention has its own yeast, it doesn't rely on the body's native yeasts.

Re:Waste

[Chyeld]

After all, wasn't the majority of the world slightly buzzed in the 'dark ages' due to alcoholic beverages being some of the few things that could be safely drunk without having to worry about parasites and diseases?

The Roman army used to drink a mixture of vinegar and honey called Posca [wikipedia.org] to avoid problems with the local water.

Re:Waste

[Hebbinator]

Double Shenanigans. You clearly haven't heard of/ been taught the...

http://en.wikipedia.org/wiki/First_pass_effect [wikipedia.org]

Things from your gut flow first to the liver before entering general circulation. This helps eliminate a lot of the crap you eat/drink on a regular basis.

The hepatic portal system == blood, but != general circulation (which is where your brain would be connected.. and where alcohol would be dangerous)

so it works like this:

alcohol in your face-> small intestine -> hepatic portal system -> liver metabolism-> general circulation -> brain -> posting stupid shit on slashdot -> sense of superiority

It just so happens that much of the alcohol you drink does make it to general circulation, as the livers ability to process alcohol tops out at around 14-15g/hour.. so a lot of the alcohol you consume does make it to general circulation. If you think an implantable object (under, say, 10cm) full of yeast could make 15g of alcohol in an hour, you are being silly. Also, with time, your body would compensate and ramp up its enzymes and eliminate the alcohol faster, i.e. functioning alcoholics who can drink a fifth a night and not wobble.

TLDR: first guy is wrong because the levels of alcohol produced by a couple yeast would not make you wasted all the time, second guy is wrong because your liver gets first pick at all the poisonous crap you eat before it reaches the parts of your bloodstream where your brain is.

Re:Waste

[razberry636]

Ethanol is a small molecule, like H2O. Thus it passes through your stomach lining and enters the bloodstream from there, so it works like this:

alcohol in your face -> stomach -> bloodstream

That's why intoxication happens so quickly after a drink.

Re:Waste

[adavies42]

ergotism [wikipedia.org]