[jeffdawgfn]

I hope this is a proper category for asking this question.  I am an author, working on my sixth novel.  I have a specific chemistry question that I cannot seem to get answered by the usual Google search and I really do not have any contacts that include chemists so here goes...

Can food/sustenance be created without the use of animal or plant protein. For example...If I had no plant or animal life, could food be produced out of the basic elements if the equipment was available to do it.  I know that there are projects running to study artificial photosynthesis for solar fuel/hydrogen production and carbon dioxide fixation, but could we produce the complex carbohydrates needed as a  food source.  I assume proteins would have to be produced somehow by the production and combination of amino acids.  To simplify, could we produce what is needed to sustain life without using any animal or plant product.

[Dan]

Yes, it is possible to synthesise amino acids and sugars, and combine them to make proteins and complex carbohydrates. Difficult and expensive, but theoretically possible.

One problem is chirality (optical isomerism). Nature (generally) produces one optical isomer, whereas classical laboratory synthesis tends to produce both optical isomers in equal proportion. The body interacts with them differently, for example naturally occurring D-glucose is an important food source, but it's optical isomer (enantiomer) L-glucose has no nutritional value and causes osmotic diarrhoea. Modern methods of asymmetric synthesis rely on the use of chiral catalysts or reagent, and the optical purity of these catalysts and reagents can always be traced back to a natural source (generally of plant origin). So, this presents a problem - though maybe in a situation where humans had to synthesise their food in the absence of any other life, they could use compounds of human origin* to develop asymmetric chemistry.

*maybe harvested from the dead or an oppressed underclass in a dark dystopian future.

[Enthalpy]

Welcome!

Covering the human needs for energetic food is easy. Even ethanol is a food (with undesirable side-effects), so is glycerol and many more, and these are easily produced. We could make them from carbon dioxide and water in a space station or martian colony, with energy from sunlight to run a chemical plant of existing technology.

Proteins and vitamins, that's less easy. We need a variety of them, maybe some aren't already identified. It's a matter of acceptable complexity of the production plant.

Why not have micro-organisms, maybe fungi, produce them for the humans? They tend to be less demanding than complex animals and plants, and feed on simple molecules produceable by elementary chemical means. Already now, meat "equivalent" is grown as micro-organisms fed by sugar.

[mikasaur]

Even ethanol is a food (with undesirable side-effects)

Speak for yourself!

[Borek]

Modern methods of asymmetric synthesis rely on the use of chiral catalysts or reagent, and the optical purity of these catalysts and reagents can always be traced back to a natural source (generally of plant origin). So, this presents a problem - though maybe in a situation where humans had to synthesise their food in the absence of any other life, they could use compounds of human origin* to develop asymmetric chemistry.

Tartaric acid in proper conditions crystallizes as a mixture of two different crystal kinds - one for D and the other for L. It is possible to separate them manually (that's what Pasteur did). Once you are past the first step, things should become manageable

[Dan]

Tartaric acid in proper conditions crystallizes as a mixture of two different crystal kinds - one for D and the other for L. It is possible to separate them manually (that's what Pasteur did). Once you are past the first step, things should become manageable

Of course, very good point!

[jeffdawgfn]

No soylent green for me please..

Thank you for answers.  I am doing research for a novel where naturally occurring Chlorophyll in the environment is being destroyed by a self-replicating molecule (IT IS FICTION) so hold the raspberry's of disdain.  The question that arises is with a total collapse of the food chain could humans survive.  Thus my question.  Again thanks for a little insight.  I have been researching the heck out of the Photosynthesis reaction and Chlorophyll molecule but being limited to Chemistry 101 in college some forty years ago is proving to be a hindrance.   

[billnotgatez]

I assume that the replicator has yet to be invented (as seen on TV STNG).

Would you consider biological processes that do not use Chlorophyll,  like yeast or fungi.

We do produce various carbon compounds using natural gas and petrochemicals.
There have been projects out there trying to produce life molecules from the primordial soup as an evolutionary study.

[jeffdawgfn]

No replicators...that would be too easy.

The Novel is about the breakdown of the food chain and mass starvation and the chaos that implies.  In other words could the rich and empowered produce enough food to feed themselves with no regard to the mass of humanity that is starving.