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Isolation and characterization of a resident tolerant Saccharomyces cerevisiae strain from a spent sulfite liquor fermentation plant.

Sànchez I Nogué V, Bettiga M, Gorwa-Grauslund MF - AMB Express (2012)

Bottom Line: Spent Sulfite Liquor (SSL) from wood pulping facilities is a sugar rich effluent that can be used as feedstock for ethanol production.During fermentation of undiluted SSL, TMB3720 displayed a 4-fold higher ethanol production rate and 1.8-fold higher ethanol yield as compared to the commercial baker's yeast.Another non-Saccharomyces cerevisiae species, identified as the pentose utilizing Pichia galeiformis, was also recovered in the last tanks of the process where the hexose to pentose sugar ratio and the inhibitory pressure are expected to be the lowest.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Applied Microbiology, Lund University, P,O, Box 124, SE-221 00, Lund, Sweden. marie-francoise.gorwa@tmb.lth.se.

ABSTRACT
Spent Sulfite Liquor (SSL) from wood pulping facilities is a sugar rich effluent that can be used as feedstock for ethanol production. However, depending on the pulping process conditions, the release of monosaccharides also generates a range of compounds that negatively affect microbial fermentation. In the present study, we investigated whether endogenous yeasts in SSL-based ethanol plant could represent a source of Saccharomyces cerevisiae strains with a naturally acquired tolerance towards this inhibitory environment. Two isolation processes were performed, before and after the re-inoculation of the plant with a commercial baker's yeast strain. The isolates were clustered by DNA fingerprinting and a recurrent Saccharomyces cerevisiae strain, different from the inoculated commercial baker's yeast strain, was isolated. The strain, named TMB3720, flocculated heavily and presented high furaldehyde reductase activity. During fermentation of undiluted SSL, TMB3720 displayed a 4-fold higher ethanol production rate and 1.8-fold higher ethanol yield as compared to the commercial baker's yeast. Another non-Saccharomyces cerevisiae species, identified as the pentose utilizing Pichia galeiformis, was also recovered in the last tanks of the process where the hexose to pentose sugar ratio and the inhibitory pressure are expected to be the lowest.

No MeSH data available.


Related in: MedlinePlus

In vitro reductase activity. HMF (left column) and furfural (right column) reduction activity measured in crude cell extracts from cells of TMB3720, BY and TMB3500 using NADPH (top row) or NADH (bottom row) as cofactor.
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Figure 5: In vitro reductase activity. HMF (left column) and furfural (right column) reduction activity measured in crude cell extracts from cells of TMB3720, BY and TMB3500 using NADPH (top row) or NADH (bottom row) as cofactor.

Mentions: Each S. cerevisiae strain has a given innate tolerance towards furaldehydes such as HMF and furfural, which enable it to reduce them to their less inhibitory alcohols (Villa et al. 1992; Taherzadeh et al. 2000; Liu et al. 2004). The reduction capability of these compounds has been related to the overall fermentation performance in lignocellulosic hydrolysates (Liu et al. 2004; Nilsson et al. 2005; Almeida et al. 2008ab; Modig et al. 2008). Therefore, furaldehyde reduction was tested by measuring the specific NADH and NADPH-dependent HMF and furfural reductase activity from YNB medium grown cells for strains TMB3720, BY and TMB3500 (Figure 5). TMB3500 displayed the highest NADPH-dependent reductase activity (Figure 5a and 5b), being 1.9-fold and 1.8-fold higher for HMF and furfural, respectively, than for TMB3720. TMB3720 showed the second highest specific activity, with NADPH-dependent HMF reduction that was 3.6-fold higher than for BY. When furfural was used as substrate, TMB3720 also displayed 2.5-fold higher NADPH-dependent reductase activity than BY.


Isolation and characterization of a resident tolerant Saccharomyces cerevisiae strain from a spent sulfite liquor fermentation plant.

Sànchez I Nogué V, Bettiga M, Gorwa-Grauslund MF - AMB Express (2012)

In vitro reductase activity. HMF (left column) and furfural (right column) reduction activity measured in crude cell extracts from cells of TMB3720, BY and TMB3500 using NADPH (top row) or NADH (bottom row) as cofactor.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539867&req=5

Figure 5: In vitro reductase activity. HMF (left column) and furfural (right column) reduction activity measured in crude cell extracts from cells of TMB3720, BY and TMB3500 using NADPH (top row) or NADH (bottom row) as cofactor.
Mentions: Each S. cerevisiae strain has a given innate tolerance towards furaldehydes such as HMF and furfural, which enable it to reduce them to their less inhibitory alcohols (Villa et al. 1992; Taherzadeh et al. 2000; Liu et al. 2004). The reduction capability of these compounds has been related to the overall fermentation performance in lignocellulosic hydrolysates (Liu et al. 2004; Nilsson et al. 2005; Almeida et al. 2008ab; Modig et al. 2008). Therefore, furaldehyde reduction was tested by measuring the specific NADH and NADPH-dependent HMF and furfural reductase activity from YNB medium grown cells for strains TMB3720, BY and TMB3500 (Figure 5). TMB3500 displayed the highest NADPH-dependent reductase activity (Figure 5a and 5b), being 1.9-fold and 1.8-fold higher for HMF and furfural, respectively, than for TMB3720. TMB3720 showed the second highest specific activity, with NADPH-dependent HMF reduction that was 3.6-fold higher than for BY. When furfural was used as substrate, TMB3720 also displayed 2.5-fold higher NADPH-dependent reductase activity than BY.

Bottom Line: Spent Sulfite Liquor (SSL) from wood pulping facilities is a sugar rich effluent that can be used as feedstock for ethanol production.During fermentation of undiluted SSL, TMB3720 displayed a 4-fold higher ethanol production rate and 1.8-fold higher ethanol yield as compared to the commercial baker's yeast.Another non-Saccharomyces cerevisiae species, identified as the pentose utilizing Pichia galeiformis, was also recovered in the last tanks of the process where the hexose to pentose sugar ratio and the inhibitory pressure are expected to be the lowest.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Applied Microbiology, Lund University, P,O, Box 124, SE-221 00, Lund, Sweden. marie-francoise.gorwa@tmb.lth.se.

ABSTRACT
Spent Sulfite Liquor (SSL) from wood pulping facilities is a sugar rich effluent that can be used as feedstock for ethanol production. However, depending on the pulping process conditions, the release of monosaccharides also generates a range of compounds that negatively affect microbial fermentation. In the present study, we investigated whether endogenous yeasts in SSL-based ethanol plant could represent a source of Saccharomyces cerevisiae strains with a naturally acquired tolerance towards this inhibitory environment. Two isolation processes were performed, before and after the re-inoculation of the plant with a commercial baker's yeast strain. The isolates were clustered by DNA fingerprinting and a recurrent Saccharomyces cerevisiae strain, different from the inoculated commercial baker's yeast strain, was isolated. The strain, named TMB3720, flocculated heavily and presented high furaldehyde reductase activity. During fermentation of undiluted SSL, TMB3720 displayed a 4-fold higher ethanol production rate and 1.8-fold higher ethanol yield as compared to the commercial baker's yeast. Another non-Saccharomyces cerevisiae species, identified as the pentose utilizing Pichia galeiformis, was also recovered in the last tanks of the process where the hexose to pentose sugar ratio and the inhibitory pressure are expected to be the lowest.

No MeSH data available.


Related in: MedlinePlus