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Comment by causi | Hacker News Reader

I don't get why this is significant. How is this a better substrate than any other flexible plastic? Isn't the issue with flexible electronics the robustness of the circuits and components?

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according to Ars Technica, its lighter, cheaper and more flexible. and probably degrades faster. https://arstechnica.com/science/2023/02/kombucha-electronics...

It consumes sugar and creates carbon dioxide. I know this might seem facetious, but I'm actually curious... are the greenhouse emissions lower?

This is true if you make naive assumptions like making circuit boards are a clean technology with no CO2 emissions or other harmful side effects. That of course is entirely incorrect. Printing circuit boards are very energy intensive along with a lot of other impacts like toxic waste and heavy water use.

> In the US, a single fab, Intel’s 700-acre campus in Ocotillo, Arizona, produced nearly 15,000 tons of waste in the first three months of this year, about 60% of it hazardous. It also consumed 927m gallons of fresh water, enough to fill about 1,400 Olympic swimming pools, and used 561m kilowatt-hours of energy. (source https://www.theguardian.com/environment/2021/sep/18/semicond...)

Kombucha on the other hand, yes produces CO2 as a waste product, but it is very easy to see a kombucha SCOBY being carbon neutral. That is the source of it's sugars being carbon energy free, and the manufacturing process of SCOBY circuits as well. Then it's carbon neutral

Is that Intel fab doing circuit boards or etching silicon wafers for integrated circuits, a completely different operation.

Doing a CPU out of a scoby would be real bio computing :)

Are greenhouse emissions lower when fermenting some sweet tea, versus extracting oil from the earth, refining it, converting that into plastic, then forming that plastic into the shape you want?

I’m going to go out on a limb here and say, yes.

No, it's a good point and I'd like to know as well. Ofc being biodegradable means it will sooner find it's way into some photosynthesis and recapture that carbon.

To be fair, the carbon content of a conventional circuit board is already sequestered in the circuit board.

SCOBY is basically a waste product from producing kombucha, you have to remove an amount from each batch which (in the case of home brewing) is usually given away to others for free or discarded, not sure how they handle it with industrial-scale kombucha making. So this could be more of a clever recycling that doesn't produce any more CO2 than was already being produced during the making of kombucha.

I can turn a piece of cheese into a flexible circuit board, if anyone wants to give me venture capital for that...

You might be joking, but you can actually make plastic out of milk/cheese: https://en.wikipedia.org/wiki/Casein

So you've had Kraft singles, I see.

You have to unwrap them before use.

Environmentally speaking, it's better, since it's biodegradable.

On the other hand, buying a gadget that dissolves when it gets just a bit wet might not be a smart thing...

But i can totally see them selling "biodegradable" flashing LED bracelets (or similar single-use crap), where the bracelet iself is biodegradable, and the rechargable battery (without an actual charging circuit) and plastic potted LEDs are not....

FWIW, it's biodegradable but it doesn't dissolve in water. If you've never handled a kombucha scoby, it's very rubbery and tough.

I've held it, but i've also got it wet (after being dry), and i seriously doubt that the printed-on metalic layer would survive, since the surface gets soft and jelloey.

A scoby is just basically a matrix of cellulose. Assuming the circuits are printed into that substrate it could be quite stable

Isn't biodegradability not a feature we want in most manufactured goods? Doesn't that just mean they will start to rot and break down on their own?

The issue is time scales. Plastics take thousands of years to degrade but we only really use plastic products for a few years. What can we find that hits a sweet spot of, say, 10 years? Wood does this well, and it’s mostly cellulose. So is paper and this stuff.

It's not, but the planned obsolescence advocates sure love it, since they can make products self-destruct and eco-virtue-signal at the same time.

If people are going to manufacture trash that breaks or become oBsOlEtE after a year anyway, you might as well have it biodegrade when it's done.

Depends on what you want.

Disposable cups, plates, forks, spoons, etc? Sure... eat whatever was in them, throw them wherever, and they'll rot very fast.

Electronics.. mostly not. Maybe some light-up bracelets for a festival, but those also contain batteries and LEDs, but it's still better if at least the strap degrades and rot.

Lots of electronics are waterproofed as well. I doubt that biodegradation would happen very quickly inside a modern smartphone chassis

People have been working on bio circuitry for decades now. Not sure of it's utility but man-machine interface comes to mind. I think the fact that it's biodegradable is probably not the point.

Article was paywalled for me, but in general Plastic does not decay so for products that are essentially consumables it's better if it doesn't stay and pollute the environment.

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