Using nature’s methods to convert CO2 to value
We have, right in front of us, something that converts CO2 to value everyday – plants and trees.
What can we learn from the processes used by the biomass to create value from CO2?
While we are all aware of photosynthesis using which plants turn an inorganic carbon into organic sugars, the precise process is quite intricate. It makes use a special enzyme called Rubisco, which attaches CO2 to a chemical called ribulose and then, using the energy recovered from sunlight, converts it into the precursors of sugar, in a fairly intricate process termed the Calvin–Benson-Bassham cycle. Here’s a good explainer on the Calvin Cycle & Rubisco – https://lnkd.in/ewBJfym
[For the uninitiated, the sugar referred here is not only the sweet sugar we all know so well, it refers to mono, di and polysaccharides, each referring to a different level of carbohydrate, which form the basis of diverse food and materials that plants give us today].
Why can’t we use the same Calvin-Benson-Bassham cycle to artificially convert CO2 to sugars? Surely scientists can create the Rubisco enzyme and ribulose outside of plants? This could give us a proven starting point for making food, chemicals and materials from captured CO2.
The real challenge appears to be the speed at which the Calvin cycle happens. Call it an inefficient – or if you are charitable, detailed – process, but the CBB cycle happens in a relaxed manner. Plants are certainly not in a hurry, and left to themselves, they will not convert CO2 to sugars at speeds commensurate with the speeds at which we emit CO2!
All the same, scientists are picking up insights from the CBB process and hopefully can (through better enzymes perhaps?) get this process to work faster for synthetic conversion of CO2 to sugars. If that is done, and assuming the bright folks trying to capture CO2 from air or elsewhere give us billions of tons of CO2, we are looking at a future when CO2 can be converted into large amounts of food & materials using the secrets learnt from plants.
Another avenue could be to work within the plants themselves and hack them into producing faster – that would almost certainly involve the domains of bioinformatics and genetic engineering.