1. Towards valorization of pectin-rich agro-industrial residues: Engineering of Saccharomyces cerevisiae for co-fermentation of d-galacturonic acid and glycerol.
- Author
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Perpelea A, Wijaya AW, Martins LC, Rippert D, Klein M, Angelov A, Peltonen K, Teleki A, Liebl W, Richard P, Thevelein JM, Takors R, Sá-Correia I, and Nevoigt E
- Subjects
- Fermentation, Hexuronic Acids, Pectins genetics, Pectins metabolism, Glycerol metabolism, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae metabolism
- Abstract
Pectin-rich plant biomass residues represent underutilized feedstocks for industrial biotechnology. The conversion of the oxidized monomer d-galacturonic acid (d-GalUA) to highly reduced fermentation products such as alcohols is impossible due to the lack of electrons. The reduced compound glycerol has therefore been considered an optimal co-substrate, and a cell factory able to efficiently co-ferment these two carbon sources is in demand. Here, we inserted the fungal d-GalUA pathway in a strain of the yeast S. cerevisiae previously equipped with an NAD-dependent glycerol catabolic pathway. The constructed strain was able to consume d-GalUA with the highest reported maximum specific rate of 0.23 g g
CDW -1 h-1 in synthetic minimal medium when glycerol was added. By means of a13 C isotope-labelling analysis, carbon from both substrates was shown to end up in pyruvate. The study delivers the proof of concept for a co-fermentation of the two 'respiratory' carbon sources to ethanol and demonstrates a fast and complete consumption of d-GalUA in crude sugar beet pulp hydrolysate under aerobic conditions. The future challenge will be to achieve co-fermentation under industrial, quasi-anaerobic conditions., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2022
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