[dbcooper]

A key limiting factor for dietary use of single cell protein is the high mass fraction of nucleic acid, which limits daily consumption due to uric acid production during metabolism. High rates of RNA synthesis are unfortunately necessary for high protein productivity.

The paper notes:

>It is important to note that MP products often contain elevated levels of nucleic acids, constituting ~8% of the dry weight [17], which necessitates consideration when assessing their suitability for human consumption. To address this, a heat treatment process is employed at the end of fermentation that reduces the nucleic acid content in the fermented biomass to below 0.75/100 g, while simultaneously deactivating protease activity and F. venenatum biomass. However, this procedure has been observed to induce cell membrane leakage and a substantial loss of biomass, as evidenced in the Quorn production process [17], which also utilizes F. venenatum as the MP producer. Our experimental trials have encountered similar challenges, achieving a biomass yield of merely ~35%, and observed that heating process increased the relative protein and chitin content (Figure 2D,E), which may be related to the effect of membrane leakage, while the intracellular protein of the FCPD engineered strain was less likely to be lost to the extracellular. Thus, concentrating the fermentation broth to enhance protein and amino acids content in successive steps to produce a highly nutritious water-soluble fertilizer appears to be an effective strategy for adding value to the process (Figure 1).

The challenges of developing economic single cell protein products, that are suitable for human consumption, are described in chapter 3 here:

https://www.researchgate.net/profile/Martin-Hofrichter-2/pub...

[adrian_b]

There are better alternatives than consuming the whole cells.

There have been other attempts to use genetically-modified fungi (Trichoderma) for protein production, where they secrete in the cultivation medium a water-soluble animal protein, e.g. a cow whey protein or chicken egg white protein.

Then, through filtration and ultrafiltration, the desired protein is separated from the fungal cells and the cultivation medium, producing a protein powder in the same way how one makes whey protein concentrate or milk protein concentrate.

If done correctly this method produces only healthy protein without contaminants.

However, searching right now online if there has been any progress with this, I see that against a startup company that has already produced such whey protein powder from a fungal culture there is a lawsuit that alleges that they have not separated properly the whey protein and that what they have sold contained more fungal protein of uncertain quality and safety than the good whey protein that they claimed to sell.

Even if that company might be guilty of trying to exploit the technology before being perfected, the principle is sound and there is no doubt that this can be done, producing pure high-quality protein.

I actually use whey protein concentrate to provide a significant fraction of my protein consumption, so I hope that its production from fungi will succeed in a not too distant future.

Trichoderma is among the fungi that secrete enzymes in their environment, so the genetic modification that replaced its enzyme with whey protein or egg albumin is much simpler than the many modifications described in the parent article in order to make the whole cells more palatable, without really achieving this.

For producing a protein powder that can be used as an ingredient in cooking food from vegetable sources, the approach used with Trichoderma is sufficient. The techniques used in the parent article are justified because they do not want to make a healthy food, but they want to make a meat imitation. For myself, enhancing the quality of vegetable food is a much more important goal than attempting to simulate meat, but at least in USA it is likely that the second goal might make more money.

[stackghost]

>against a startup company that has already produced such whey protein powder from a fungal culture there is a lawsuit that alleges that they have not separated properly the whey protein and that what they have sold contained more fungal protein of uncertain quality and safety than the good whey protein that they claimed to sell.

Sounds like par for the course in the VC-backed startup world

[lentil_soup]

>> There have been other attempts to use genetically-modified fungi (Trichoderma) for protein production, where they secrete in the cultivation medium a water-soluble animal protein

Honest question, what does "animal protein" mean here in regards to it being produced by a fungi? is it that it's the same as as one from a cow at the molecular level?

[xnx]

> a startup company

https://perfectday.com/ ?

I've had their product as protein powder and in an ice cream that contained it.

[meindnoch]

Finally vegans can get gout too!

[tomrod]

Hilarious and literally my same thought.

I think it is _fascinating_ how we can modulate these amazing biological machines to do all kinds of tricks.

I wish we had a better effect discovery process, something akin to alphafold where the space can be explored and defined beyond wait-and-see.

[cbflak]

And go on Atkin’s if it’s a fatty enough fungus!

[gsf_emergency_6]

recent study that genetics has a underappreciated role in gout

https://www.sciencealert.com/massive-study-reveals-where-gou...

[colechristensen]

Also it's a multi-species mutation that stuck in humans and the great apes which broke the urate oxidase enzyme.

If we fixed it, nobody would get gout.

I kinda wonder sometimes why medicine doesn't try to fix some of these species level genetic problems more broadly or more quickly. There's this enzyme every other mammal produces, why isn't there a fast track to engineering a micro-organ to produce it or inject an engineered version in gout patients (I did some research and yes people are somewhat doing these things... slowly)

Why can't I, a healthy adult, be genetically engineered to start producing my own Vitamin C like every other mammal?

[justonceokay]

That’s do interesting. I never would have assumed that single-celled animals have significantly more nuclear material per-weight than meat.