According to the savor team, it was quite easy for them:

“We start with a source of carbon, like carbon dioxide, and use a little bit of heat and hydrogen to form chains which are then blended with oxygen from air to make the fats & oils"

I want to guess they are glossing over a complicated enzyme they created, or other form of reagent.

It’s your lucky day: https://www.pussynaturalenergy.com/

Could you skip the turbine and slap a bunch of peltier elements on the reactor?
Probably not super efficient, what with the vacuum of space being bad at absorbing hear, and if I recall right peltier produces more power the larger heat gradient.