Open AccessMetabolic engineering considerations for the heterologous expression of xylose-catabolic pathways in Saccharomyces cerevisiae
Author(s) -
Deokyeol Jeong,
EunSuok Oh,
Ja Kyong Ko,
Ju-Ock Nam,
Hee-Soo Park,
Jing Jing Liu,
Eun Jung Lee,
Soo Rin Kim
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0236294
Subject(s) - xylose , xylose isomerase , metabolic engineering , saccharomyces cerevisiae , metabolic pathway , biochemistry , isomerase , heterologous expression , xylose metabolism , heterologous , biology , fermentation , enzyme , yeast , gene , recombinant dna
Xylose, the second most abundant sugar in lignocellulosic biomass hydrolysates, can be fermented by Saccharomyces cerevisiae expressing one of two heterologous xylose pathways: a xylose oxidoreductase pathway and a xylose isomerase pathway. Depending on the type of the pathway, its optimization strategies and the fermentation efficiencies vary significantly. In the present study, we constructed two isogenic strains expressing either the oxidoreductase pathway (XYL123) or the isomerase pathway (XI-XYL3), and delved into simple and reproducible ways to improve the resulting strains. First, the strains were subjected to the deletion of PHO13 , overexpression of TAL1 , and adaptive evolution, but those individual approaches were only effective in the XYL123 strain but not in the XI-XYL3 strain. Among other optimization strategies of the XI-XYL3 strain, we found that increasing the copy number of the xylose isomerase gene ( xylA ) is the most promising but yet preliminary strategy for the improvement. These results suggest that the oxidoreductase pathway might provide a simpler metabolic engineering strategy than the isomerase pathway for the development of efficient xylose-fermenting strains under the conditions tested in the present study.