The carbonic anhydrase enzymes as means of carbon fixation?
Carbonic anhydrase is an enzyme that assists rapid inter-conversion of carbon dioxide and water into carbonic acid, protons and bicarbonate ions.
CO2 + H2O <=> HCO3- + H+ (in high pH and high CO2 concentration mostly to the right)
They are widespread in nature, being found in animals, plants, algae and certain bacteria.
I tested this enzyme by churning some flowers from the garden in water, and added carbonated drink.
The bubbling stopped immediately, and I managed to precipitate some matter when adding salt. (That`s how corals, CaCO3, Na2CO3x10H2O, etc. are formed!)
Since these enzymes are extremely efficient, soluble and abundant, there is a fair chance they can be harvested and used in carbon capture. They can even be enhanced by genetic modification.
Ideally, the exhaust from a car can be fluxed through a water bath containing this enzyme and some Ca++ or Na+ in optimized pH. And the hundred-and-thirty-something grams of CO2 per km can be dumped as solid rock!