Products from the bioeconomy play an important role in a sustainable future, but are dependent on cheap and available biomass as a carbon source. The availability of sustainable biomass, though, is limited by the arable area of our planet. Even by deforestation and setting up new agricultural area, we cannot provide enough arable land for both biomass for the bioindustry and food crops to solve the problem of world hunger. So if we hardly manage to feed the population, how can we guarantee the supply of biomass for biotechnological products?

Deforestation

Although the farming of algae is a potential solution to this global problem, because they don't depend on agricultural area, they are still highly limited by the natural photosynthesis. The scale of a production facility that would replace our daily demand for oil would still cover millions of hectare.

So wouldn’t it be great to convert CO₂ from the air into other carbon compounds by using new technologies that require not only less space but also exceed the efficiency of photosynthesis by multiples? The technical process of fixing CO₂ that precedes our process, for example through the sunfire company, is far more efficient compared to plants. The efficency of converting electrical energy into chemical energy is about 80 times higher than the conversion of CO₂ into biomass through plants and even 18 times higher than the maximal efficieny natural photosynthesis can theoretically have^[1].

The process produces different hydrocarbons, but can easily be configurated to produce only methanol. This is where our project comes in. Instead of providing complex biomass, we convert methanol into the sustainable and universal carbon source, glycogen.

Glycogen[2]

Glycogen is a sugar polymer that is safe to handle and can be easily converted into glucose. Therefore, it can then be used as a carbon source for almost all existing bioprocesses since those rely on sugar. Our project has the potential to make the bioeconomy independent from plants and instead use CO₂ from the air.

We decided to use the newly developed, ATP-neutral Methanol Condensation Cycle ^[3] to enable E. coli to take up methanol. Glycogen accumulation was achieved by combining knocking out one degradation enzyme and overexpressing the synthesis genes.

The huge advantage of our approach is that it addresses the problem in various ways. Not only can the potential of methanol as a carbon source be exploited but also the surplus CO₂ in the atmosphere is utilized. Likewise, it has to be considered that by fixing the CO₂ technically, non-arable areas like deserts can be used. In addition compared to the other approaches, our project is based on a CO₂ fixing method that is far more efficient than plants. Finally, the production of glycogen from methanol with our bacteria is independent from the restricted arable land available.

cycle from CO2 to biotechnological product

The most important impact of our project is, that arable land will no longer be used to supply the bioeconomy’s demand for a carbon source. It can again be used to plant food crops to feed a rapidly growing world population.

References

1. ↑ Die natürliche Photosynthese: Ihre Effizienz und die Konsequenzen - Hartmut Michel
2. ↑ https://upload.wikimedia.org/wikipedia/commons/0/0d/Glycogen.png%7Csize=large
3. ↑ Bogorad IW, Chen CT, Theisen MK, Wu TY, Schlenz AR, Lam AT, Liao JC. Building carbon-carbon bonds using a biocatalytic methanol condensation cycle. Proc Natl Acad Sci U S A. 2014 Nov 11;111(45):15928-33. doi: 10.1073/pnas.1413470111. Epub 2014 Oct 29. PubMed PMID: 25355907; PubMed Central PMCID: PMC4234558.