Production of medium-chain carboxylates by microbial communities co-fermenting brewer’s spent grain, H2 and CO2
(2025)
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- Authors
- Supervisors
- GERIN, Patrick
- Abstract
- Brewer’s spent grain (BSG), the most abundant by-product of the brewing industry, is produced worldwide in large quantities but remains under-valorized. As a promising feedstock in biorefineries, BSG can be converted into value-added molecules. However, its high water and lignocellulosic content hinder efficient conversion processes. This thesis develops a strategy combining alkaline pretreatment, mixed culture fermentation and the supply of H2 and CO2 to convert BSG to short- and medium-chain carboxylates (SCC and MCC). Alkaline pretreatment significantly enhanced BSG fermentation kinetics and conversion yields. Within just four days of fermentation, alkaline-pretreated BSG achieved a metabolite yield – primarily as SCC – equivalent to that of un-pretreated BSG after 14 days. Supplementation of H2 and CO2 during BSG fermentation further stimulated SCC conversion to MCC and revealed a new microbial chain elongation process. A H2/CO2 consumption molar ratio (H2/CO2 CMR) of 3 was identified as characteristic of this newly described chain elongation process. In addition, this thesis suggests H2/CO2 CMR could be used as an online monitoring tool to indicate the main metabolic pathway catalyzed by the microbiome.
- Affiliations
Citations
Henry, G. (2025). Production of medium-chain carboxylates by microbial communities co-fermenting brewer’s spent grain, H2 and CO2. https://hdl.handle.net/2078.5/260390