Improved organic matter biodegradation through pulsed H injections during in situ biomethanation.

During in situ biomethanation, microbial communities can convert complex Organic Matter (OM) and H into CH. OM biodegradation was compared between Anaerobic Digestion (AD) and in situ biomethanation, in semi-continuous processes, using two inocula from the digester (D) and the post-digester (PoD) of an AD plant. The impact of H on OM degradation was assessed using a fractionation method.

Archaeal community composition as key driver of H2 consumption rates at the start-up of the biomethanation process.

The performance of hydrogen consumption by various inocula derived from mesophilic anaerobic digestion plants was evaluated under ex situ biomethanation. A panel of 11 mesophilic inocula was operated at a concentration of 15 g.L at a temperature of 35 °C in batch system with two successive injections of H:CO (4:1 mol:mol).

Microbial community redundance in biomethanation systems lead to faster recovery of methane production rates after starvation.

The Power-to-Gas concept corresponds to the use of the electric energy surplus to produce H by water electrolysis, that can be further converted to methane by biomethanation. However, the fluctuant production of renewable energy sources can lead to discontinuous H injections into the reactors, that may interfere with the adaptation of the microbial community to high H partial pressures. In this study, the response of the microbial community to H and organic feed starvation was evaluated in in-situ and ex-situ biomethanation.

Temperature and Inoculum Origin Influence the Performance of Ex-Situ Biological Hydrogen Methanation.

The conversion of H into methane can be carried out by microorganisms in a process so-called biomethanation. In ex-situ biomethanation H and CO gas are exogenous to the system. One of the main limitations of the biomethanation process is the low gas-liquid transfer rate and solubility of H which are strongly influenced by the temperature.

Biomethanation processes: new insights on the effect of a high H partial pressure on microbial communities.

Background: Biomethanation is a promising solution to upgrade the CH content in biogas. This process consists in the injection of H into an anaerobic digester, using the capacity of indigenous hydrogenotrophic methanogens for converting the injected H and the CO generated from the anaerobic digestion process into CH. However, the injection of H could cause process disturbances by impacting the microbial communities of the anaerobic digester.