Fruity flavors from waste: A novel process to upgrade crude glycerol to ethyl valerate

Ramon Ganigué, Pieter Naert, Pieter Candry, Jonas de Smedt, Christian V. Stevens, Korneel Rabaey

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Valeric acid and its ester derivatives are chemical compounds with a high industrial interest. Here we report a new approach to produce them from crude glycerol, by combining propionic acid fermentation with chain elongation. Propionic acid was produced by Propionibacterium acidipropionici (8.49 ± 1.40 g·L−1). In the subsequent mixed population chain elongation, valeric acid was the dominant product (5.3 ± 0.69 g·L−1) of the chain elongation process. Residual glycerol negatively impacted the selectivity of mixed culture chain elongation towards valeric acid, whereas this was unaffected when Clostridium kluyveri was used as bio-catalyst. Valeric acid could be selectively isolated and upgraded to ethyl valerate by using dodecane as extractant and medium for esterification, whereas shorter-chain carboxylic acids could be recovered by using a 10 wt% solution of trioctylphosphine oxide (TOPO) in dodecane. Overall, our work shows that the combined fermentation, electrochemistry and homogeneous catalysis enables fine chemical production from side streams.
Original languageEnglish (US)
Pages (from-to)121574
JournalBioresource Technology
StatePublished - May 28 2019
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): OSR-2016-CRG5-2985
Acknowledgements: R.G. gratefully acknowledges support from Ghent University Special Research Fund (BOF) (BOF15/PDO/068). P.N. is supported by the Research Foundation Flanders (FWO-SB-151223). P.C. is supported by the Ghent University Special Research Fund (BOF) (BOF15/DOC/286). K.R. is supported by Catalisti and VLAIO-ICON “CAPRA: upgrading steel mill off gas to caproic acid and derivatives using anaerobic technology” (VLAIO HBC.2016.0413) as well as a Competitive Research Grant from King Abdullah University of Science and Technology (KAUST), Project Reference OSR-2016-CRG5-2985. Authors thank Proviron for providing the crude glycerol used in the study.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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