The biochemistry group led by Prof. Silvan Scheller brings chemical processes invented by nature into the laboratory for industrial applications.
We focus on the biocatalytic conversion of chemical energy (fuel) to electricity, in order to develop advanced energy solutions. Our research aims to utilize natural resources (e.g. natural gas, biogas, or energy in general) more sustainably.
As renewable energy carriers are highly volatile, storage of electricity is required at periods where its production exceeds the demand. One way to “store” electricity is the biocatalytic conversion of electricity to organic molecules, using CO2 as the carbon source. Therefore, novel biochemical methods to efficiently convert electricity to high-energy compounds (such as alkanes or alcohols) are also part of our research.
Mechanistic investigation of biochemical processes
The process of alkane oxidation to CO2 coupled to release of single-electrons has recently been discovered in environmental microbes (for the alkanes methane and butane). We seek to carry out such processes under controlled laboratory conditions in order to unravel the mechanistic secrets behind them.
We focus is the first enzyme involved, methyl-coenzyme M reductase (Mcr) and its homologues, which converts alkanes reversibly to alkyl-thioethers. These reactions utilize the nickel cofactor F430 for the C-H bond activation. Despite its occurrence in nature, chemists are still not able to carry out such reactions without enzymes, because the reaction mechanism is not understood. Furthermore, we study how single-electrons are generated from catabolic reactions, such as alkane oxidation. The reversal of this process is a key feature to convert electricity directly to fuels.
We apply a range of different methods to study these processes, e.g.: anaerobic expression of enzymes, experiments with isolated cofactors, kinetic studies, measurement of equilibria, electrochemistry, synthesis of substrate analogues, isotope effects, NMR and EPR studies, DFT calculations.
Discovery of new pathways and enzymes from environmental microbes
The high diversity of microbes living on this planet is associated a high diversity of metabolic reactions catalyzed by them. Since less than 1% of all microbes can be cultivated in the lab, their metabolic potential remains largely unutilized. We apply genetic tools to access novel metabolic pathways and enzymes relevant for energy-conversions.
Genetic engineering of archaea
Alkane oxidation coupled to release of single-electrons has so far only been discovered in the domain archaea. We use archaea as lead organisms for genetic engineering, with a focus on the one-carbon metabolism associated with methanogenesis.
Some proteins of our interest, such as Mcr with its unique posttranslational modifications, can only be functionally expressed in archaeal host organisms.
Talented chemists interested in elucidating the catalytic mechanism of Methyl-coenzyme M reductase are welcome to apply with a research proposal.
Dr. Silvan Scheller
silvan.scheller [at] aalto [dot] fi