Adaptation of Saccharomyces cerevisiae in a concentrated spent sulphite liquor waste stream for increased inhibitor resistance.

Autor: Brandt BA; Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, Republic of South Africa.; Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, Republic of South Africa., García-Aparicio MP; Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, Republic of South Africa.; Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, Republic of South Africa., Görgens JF; Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, Republic of South Africa., van Zyl WH; Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, Republic of South Africa. whvz@sun.ac.za.
Jazyk: angličtina
Zdroj: Applied microbiology and biotechnology [Appl Microbiol Biotechnol] 2022 Jan; Vol. 106 (1), pp. 455-468. Date of Electronic Publication: 2021 Dec 06.
DOI: 10.1007/s00253-021-11710-3
Abstrakt: The fermentation of spent sulphite liquor (SSL) from the pulping of hardwoods is limited by the combination of xylose, the primary fermentable sugar and high concentrations of microbial inhibitors that decrease the yeast fermentation ability. The inhibitor resistance phenotypes of xylose-capable Saccharomyces cerevisiae strains were therefore enhanced by combining rational engineering for multi-inhibitor tolerance, with adaptation in concentrated hardwood SSL as selective pressure. The adapted strains were assessed in fermentations with 60-80% v/v concentrated SSL under industrially relevant fermentation conditions. During adaptation, strains produced ethanol concentrations between 11.0 and 15.4 g/L in the range of that reported in literature. The adapted TFA40 and TP50 strains displayed enhanced inhibitor resistance phenotypes and were able to ferment xylose-rich SSL at pH below 5, exhibiting improved ethanol yields relative to the reference strain. Using yeast extract and peptone as nitrogen source in concentrated SSL fermentations further improved ethanol yields. However, strains exhibited a trade-off between resistance and ethanol productivity, indicating a carbon/energy cost for the expression of this inhibitor tolerance phenotype. KEY POINTS : • Achieved fermentation of xylose-rich hardwood spent sulphite liquor at pH below 5.0 • Adaptation of xylose-capable S. cerevisiae in concentrated spent sulphite liquor • Adapted strains exhibited enhanced inhibitor resistance phenotypes.
(© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
Databáze: MEDLINE
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