New class of micro-organisms in Siberian soda lakes discovered

In the future, these newly discovered organisms could also play a role in the production of methane from organic waste. The big advantage is that, at the high pH, CO₂ remains in the solution. Therefore, methane gas is produced, instead of biogas (which contains CO₂). Currently, biogas still has to be upgraded to natural gas quality, suitable for utilization it in gas networks. This upgrading process costs a lot of energy.

Dimitry Sorokin: ‘Over the last few years, the so called methyl-reducing pathway of methane production became one of the major themes in this research field. This hybrid pathway was found in several methanogens (methane producing micro-organisms). In this pathway, only the last of the classical seven steps is present. It has already been discovered a long time ago in two methanogens but was considered an inconsequential curiosity. Now it has become clear that it is at least as prominent as the other classical pathways.’
‘So far however, only a single organism executing this pathway has been isolated and characterized in pure culture. We have now identified methyl-reducers in hypersaline lakes that appear to represent a new class of archaea. These methanogens are extreme halo(alkali)philes and moderate thermophiles’, says Sorokin.

‘For the last five years, I have been investigating extremophilic methanogenic micro-organisms in soda lakes – a unique type of salt lakes with a very high soluble carbonate alkalinity maintaining constant high pH around 10. While performing activity tests with sediments in 2012, we identified organisms that did not respond to the addition of typical methanogenic substrates. Next year I manipulated the incubation conditions and, finally, got it right. It already became clear, at that stage, that something very unusual was struggling on my fishing hook.’