Production of Enzymes Utilizing Gaseous Substrates for Biotechnological Applications

The chemical industry is responsible for nearly 5% of global greenhouse gas emissions, largely due to its reliance on fossil fuels as raw materials. Despite growing awareness of this issue, emissions continue to rise, intensifying the need for strategies to reduce atmospheric CO₂ concentrations. Enzymes, as sustainable catalysts, present promising opportunities for developing innovative biocatalytic processes that harness H₂ as an energy carrier or CO₂ as a carbon source to produce high-value compounds. However, the activity of many enzymes, including gas-utilizing ones, is hampered under harsh conditions, such as in organic solvents or in the presence of inhibitory molecules.
To address this challenge, different strategies are employed to enhance enzyme stability including computational approaches and enzyme immobilization techniques. A recent protein gelation strategy leverages genetically encoded reactive partners, SpyTag and SpyCatcher, which spontaneously form a covalent isopeptide bond under physiological conditions.[1] This method enables the creation of All-Enzyme Hydrogels without the need for additional chemical treatments.[2] Initially limited to homotetrameric proteins, this approach has now been adapted to accommodate a broad range of biocatalysts with different degrees of multimerization.[3] However, since some enzymes require expression in the original host, due to e.g. ... mehrspecific auxiliary proteins for folding, cofactor insertion they cannot be simply expressed and purified recombinantly. To overcome this limitation, such enzymes can be identified through bioinformatic analysis of DNA datasets obtained from environmental samples. Such an approach can also identify candidate enzymes with desirable properties for biotechnological applications, such as enhanced thermal stability [4, 5], broadening the potential for biocatalyst discovery.
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