Research School for Socio-Economic and
Natural Sciences of the Environment
Research School for Socio-Economic and
Natural Sciences of the Environment

Kaspar de Leeuw

Date: 03 November 2020
Time: 16:00 - 17:30
Location: Aula, building 362, Gen. Foulkesweg 1, Wageningen

Dissertation title: 

Open Culture Chain Elongation for Branched Carboxylate Formation

Group: Wageningen University, Environmental Technology
Promotors: C.J.N. Buisman

Extra information:


Microbial chain elongation technologies can aid in recycling organic residues into useful chemicals. In this thesis new methods for chain elongation are discovered and researched that broaden the product spectrum of chain elongation fermentation. The research chapters elaborated on how specific selection pressures in open culture fermentations can be used to enrich microbiomes to harbour desired biocatalytic capabilities. Two different types of chain elongation fermentation are the subject of these investigations: methanol-based and ethanol-based chain elongation. During methanol-based chain elongation, the microbiome was capable of simultaneously elongating both acetate and propionate to n-butyrate, isobutyrate, n-valerate as dominant products. Microbiomes were also enriched to perform ethanol-based chain elongation, in particular for the elongation of branched electron acceptors. In the general discussion hypotheses are presented that could further mechanistically explain the observed metabolic functionalities and an outlook on chain elongation fermentation for branched carboxylate production is presented.