Methanogenic archaea: the catalysts of microbiological methanation

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Methanogenic archaea
Microscopic image of methanomicrobiales (archaea) in a biogas sample. Staining was performed by FISH (fluorescence in situ hybridization)

In the course of the energy transition, power-to- methane is a promising storage technology for ensuring an on-demand energy supply.

The microbiological conversion of hydrogen (H2) and carbon dioxide (CO2) to methane (CH4) under anaerobic conditions by hydrogenotrophic methanogenic archaea is well-known as a sub-process from biogas plants or digesters at wastewater treatment plants and is much more robust and easier to implement compared to the chemical-catalytic Sabatier process. No catalysts are required, the raw gas quality requirements are much lower, and the process conditions are also less extreme.

Biological reactors can be operated with pure cultures or with a wide range of mixed cultures. Pure cultures often achieve higher methane formation rates, but are more susceptible to process disturbances during operation. In efficient operation, methanogenic archaea (see figure), which are responsible for the production of CH4, dominate. In addition, many biological reactors contain various acidogenic, acetogenic, and syntrophic fatty acid oxidizing bacteria.

The composition of microorganisms (biocenosis) at different process states is an important focus of investigation to better understand the processes and identify potential process indicators. By characterizing and quantifying the biocenosis, an early warning system for potential process disturbances can thus, be developed.

More information: https://www.lfl.bayern.de/zentrale_analytik/048892/index.php