<aside> ⚙ *** Cafy** = carbon fixation in yeast.
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<aside> ‼️ Most of the text below is from 2019, when I submitted the idea to ClimateLaunchpad. I abandoned the project soon after and never went beyond the concept.
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Cafy is a biotechnology project to engineer a yeast strain that would utilize atmospheric carbon dioxide, $CO_2$, as the sole source of carbon. Taking advantage of the $CO_2$-fixing capacity of photoautotrophs, the project seeks to transfer the Calvin cycle enzymatic circuitry (the major biochemical cycle for $CO_2$ fixation in the biosphere) from plants into common brewer’s yeast (Saccharomyces cerevisiae) to generate a strain that would process atmospheric $CO_2$ into biofuel, such as ethanol, in a cost-efficient single-step process.
The dependence on fossil fuels in order to power the technological advancement in the last century has brought about a significant increase in $CO_2$ in the Earth’s atmosphere. Consequently, the emission of greenhouse gases and climate change are pressing issues humanity has to solve.
Sustainable energy sources serve as an attractive alternative to fossil fuels. Modern industrial biotechnology has demonstrated that some well-known features of microorganisms can be used to generate green fuels at scale – e.g. via fermentation of simple carbohydrates like glucose to bioethanol by brewer’s yeast.
However, the need for simple sugars adds to the cost of the resultant product. For example, using byproducts of the wood industry, e.g. sawdust, requires enzymatic or chemical digestion of cellulose and lignin before they can be subjected to fermentation, which is reflected in the product cost.
Hypothetically, the two opposite processes — the conversion of solar energy to biomass and the conversion of biomass to energy — can be combined so that the abundance of atmospheric $CO_2$ is transformed into a renewable source of energy, such as a biofuel, in a single-step process.
The process of photosynthesis consists of two separate reactions – the light-dependent (light) and the light-independent (dark) ****phases: the light-dependent phase converts solar energy to its chemical equivalent (reduced NADPH), which, in turn, is used to drive the dark phase of photosynthesis, called the Calvin cycle, ****during which $CO_2$ is enzymatically fixed from the atmosphere to condense in the form of simple sugars.
<aside> 🟢 I propose to assemble the genes of the Calvin cycle enzymatic machinery in an artificial chromosome❓ and transfer the complete plant $CO_2$ fixation circuit into the common brewer’s yeast (Saccharomyces cerevisiae) **cells, allowing for the efficient and cost-effective means to utilize atmospheric $CO_2$ for the single-step bioethanol production.
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The proposed conversion of $CO_2$ to ethanol via the help of the engineered yeast will not only address the problem of sequestering excess atmospheric $CO_2$ but will also serve as a readily available source of sustainable energy.
<aside> 🔴 Do you know where else there’s a ton of $CO_2$ in the atmosphere? On Mars.
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