Biochemistry

We currently study the biochemistry and genetics of methanogens. 

Methanogens are microbes with the ability to reduce CO₂ to methane (biogas, a one-carbon fuel). The individual reduction steps are carried out at cofactors, such as H₄MPT and coenzyme M.

One overall research goal is to extend this chemistry towards producing 2-4-carbon fuels (liquefied petroleum gas: ethane, propane or butane) that can be easily liquefied at room temperature. It serves the purpose of converting CO₂ with renewable energy to a storable fuel. 

And additional project involves extending the substrate scope of methanogens. 

We also develop new tools to activate CO2 in vitro, in a collaborative project with Malin Bomberg (VTT) and Jan Deska (University of Helsinki), where we study acid-tolerant formate dehydrogenases. 

We perform genetic engineering with methanogens of the orders Methanosarcinales and Methanococcales. Due to their oxygen sensitivity, all manipulations are carried out in anaerobic chambers or incubators.  Methanococcus maripaludis is utilized as a genetic work horse for the expression of archaeal proteins and for designing new metabolic pathways.

We conduct mechanistic studies with enzymes purified from Methanothermobacter marburgensis, a methanogen that grows at 65 °C to high cell densities, allowing to access large amounts of native enzymes and cofactors. This organism is currently the only source to obtain the enzyme Mcr in the active form, which is prerequisite to study its catalytic mechanism. Biochemistry is studied by a range of different methods, such as: 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.