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

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, electro-chemistry and homogeneous catalysis enables fine chemical production from side streams.

Publication year:2019

BOF-keylabel:yes

IOF-keylabel:yes

BOF-publication weight:10

CSS-citation score:1

Authors:National

Authors from:Higher Education

Accessibility:Closed