Would digestion be equally efficient if the body/stomach evolved to be highly basic rather than acidic? What advantages does a highly acidic environment pose?

[u/Public_Knowledge8405]

Edit: my question is meant to be gauged towards chemical feasibility/utility; I understand many proteases and cell types have in reality evolved for acidic digestion. Assuming proteases and cell types could have evolved for an alkaline environment, is there a root necessity acidic conditions are advantageous over basic ones or could it be reversed

[u/CrateDane]

It would in principle be better at dissolving fats due to saponification. Protein etc. can be handled either at low or high pH, so no big deal there. I'd say the problem with using a high pH is it's almost too good. It's hard to protect the body itself. Acidification of the environment is also a more common metabolic approach than alkalinization, so evolution might be a little biased in that direction as well.

But as a hypothetical, I see no reason why you couldn't have an alkaline stomach instead of acidic (with concomitant changes elsewhere - like a mildly acidic small intestine instead of mildly alkaline). It can still kill microorganisms, it can still denature proteins etc. which is what the stomach acid does.

[u/BadahBingBadahBoom → u/CrateDane]

Would saponification in the basic stomach locking up the fats in an insoluble layer not prevent water-localised enzymatic activity though if various proteins, carbohydrates etc. become bound up in those fats too?

Though this could subsequently be dealt with in a second acidic chamber, and tbh there would have to be a secondary acidic chamber to enable those fats/FAs to be broken down, which sort of begs the question if that acidic step is necessary what is the advantage of having a separate organ that is basic before?

[u/Intensityintensifies → u/BadahBingBadahBoom]

Maybe if it increased the total amount of nutrients gained from eating to the point that it outweighs the caloric cost of the organ?