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Then, those pieces are fed to the programmed yeasts, which transform them into a variety of new food ingredients, including proteins, fats and acids PET consis

Then, those pieces are fed to the programmed yeasts, which transform them into a variety of new food ingredients, including proteins, fats and acids PET consists of repeating C10H8O4 monomers. Glucose is C6H12O6 and starch is a natural polymer containing it. It's not surprising that reactions can turn one into the other, along with other compounds containing hydrogen, carbon, and oxygen.

timcobb 1mo ago
Just because two substances are made of a similar distribution of atoms it doesn't mean much in terms of how one can be transformed effectively into the other...
- mschuster91 1mo ago
  > transformed effectively Well that's where the yeast comes in, it does the work for us. And we desperately need ways to convert plastics into something that is not as durable, and ideally something we (or if that's too icky, farm animals) can eat afterwards.
gus_massa 1mo ago
Short answer: No Long answer: Starch and cellulose are just chains of glucose connected in a slightly different way. But they have very different properties, you can split starch and get energy from it, but you can't split cellulose (unless you are a bacteria or fungus). As far as I know, no life form can transform starch directly into cellulose, they have to split it and reconnect the glucose later. (And the reverse path is even harder.) There are a few cases where the cells can transform the monomers inside the chains, in particular to make collagen, but the change is to replace some -H by -OH. Changing the Carbon structure is harder, almost impossible. --- Back to the article: The yeast just split the plastic back into monomers (or probably short chains) and use the chains to build carotene (similar to vitamin A). It's quite similar to splinting starch or cellulose and using later the monomers. There is no polimer to polimer transformation.

timcobb 1mo ago

Just because two substances are made of a similar distribution of atoms it doesn't mean much in terms of how one can be transformed effectively into the other...

mschuster91 1mo ago
> transformed effectively Well that's where the yeast comes in, it does the work for us. And we desperately need ways to convert plastics into something that is not as durable, and ideally something we (or if that's too icky, farm animals) can eat afterwards.

gus_massa 1mo ago

Short answer: No Long answer: Starch and cellulose are just chains of glucose connected in a slightly different way. But they have very different properties, you can split starch and get energy from it, but you can't split cellulose (unless you are a bacteria or fungus). As far as I know, no life form can transform starch directly into cellulose, they have to split it and reconnect the glucose later. (And the reverse path is even harder.) There are a few cases where the cells can transform the monomers inside the chains, in particular to make collagen, but the change is to replace some -H by -OH. Changing the Carbon structure is harder, almost impossible. --- Back to the article: The yeast just split the plastic back into monomers (or probably short chains) and use the chains to build carotene (similar to vitamin A). It's quite similar to splinting starch or cellulose and using later the monomers. There is no polimer to polimer transformation.