# Hydrogen production and methanogenesis in ruminants: growth kinetics and gas fluxes of key microbial strain

Arthur Bourguet, Anaïs Roger, Dominique Graviou, Mallory Martin, Aurélie

Dehornoy, Diego Morgavi, Milka Popova

► To cite this version:

Arthur Bourguet, Anaïs Roger, Dominique Graviou, Mallory Martin, Aurélie Dehornoy, et al.. Hydrogen production and methanogenesis in ruminants: growth kinetics and gas fluxes of key microbial strain. International Gut Microbiology Symposium, INRAE, Jun 2025, Clermont-Ferrand, France, France. hal-05206284

HAL Id: hal-05206284

https://hal.inrae.fr/hal-05206284v1

Submitted on 11 Aug 2025

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Abstract

**Title: Hydrogen production and methanogenesis in ruminants: growth kinetics and gas fluxes of key microbial strain**

BOURGUET Arthur<fnref n="1" />, ROGER Anais<fnref n="1" />,<fnref n="2" />, GRAVIOU Dominique<fnref n="1" />, MARTIN Mallory<fnref n="1" />, DEHORNOY Aurélie<fnref n="1" />, MORGAVI Diego<fnref n="1" />, POPOVA Milka<fnref n="1" />

In the gastrointestinal tract of ruminants, the microbial fermentation of plant polymers produces volatile fatty acids, CO2, and H2. The latter is used by methanogenic archaea to reduce CO2 into CH4 a process that occurs through the following equation: 4H2 + CO2 → 2H2O + CH4. The resulting CH4 is expelled and contributes to greenhouse gas emissions. To address this environmental issue, it is necessary to understand H2 production and transfer during methanogenesis. As a preliminary investigation, the growth kinetics and gas fluxes of *Ruminococcus albus*, a key ruminal bacterium, and *Methanobrevibacter ruminantium*, a major methanogen, were evaluated.

These were grown in mono and then in co-culture. In both culture conditions, *R. albus* was provided with 0.14 g/ml of pure cellulose; whereas *M. ruminantium*, when grown alone, was supplied with 1,41E-03 moles of hydrogen without any carbohydrate. All cultures were incubated for 50 h at 39 °C. Growth was monitored by measuring optical density, and gas composition (H₂ and CH₄) was analysed using gas chromatography. By comparing initial and final gas compositions, the amount of H₂ consumed by methanogens was estimated by stoichiometric calculations (4H₂ per CH₄ produced).

*R. albus* in monoculture produced 2,03E-04 moles of H₂ and in co-culture no H₂ was detected, were detected, indicating that it was consumed by *M. ruminantium*. The co-cultures produced 6,05E-05 moles of methane, implying that *R. albus* produced 18% more H₂ than in pure culture.

The co-culture increased the H₂ production and led to complete H₂ consumption, highlighting a positive effect on fermentation and efficient interspecies H₂-transfer.

To better understand methanogenesis, future work will focus on quantifying dissolved H₂ and fermentation products, as well as studying more complex microbial consortia to better reproduce natural rumen conditions.

**Key words:** Rumen, hydrogen, methane, methanogenesis, co-culture test

Selected sessions

X Session 1 - Gut microbes in health, climate and environment: an intricate equation

☐ Session 2 - Diet to optimize gut microbiota-host symbiosis

☐ Session 3 - Local and distant roles of the gut microbiota

☐ Session 4 - New approaches in gut microbiota research

☐ Session 5 - Gut microbiology: from bench to bedside

<footnote n="1">¹Université Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France</footnote>

<footnote n="2">²Université Paris-Saclay, INRAE, AgroParisTech, UMR Modélisation Systémique Appliquée aux Ruminants, 91120, Palaiseau, France</footnote>