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Identification of furfural resistant strains of Saccharomyces cerevisiae and Saccharomyces paradoxus from a collection of environmental and industrial isolates.

Field SJ, Ryden P, Wilson D, James SA, Roberts IN, Richardson DJ, Waldron KW, Clarke TA - Biotechnol Biofuels (2015)

Bottom Line: Furthermore, ethanol production in this strain did not appear to be inhibited by furfural, with the highest ethanol yield observed at 3.0 mg ml(-1) furfural.Although furfural resistance was not found to be a trait specific to any one particular lineage or population, three of the strains were isolated from environments where they might be continually exposed to low levels of furfural through the ongoing natural degradation of lignocelluloses, and would therefore develop elevated levels of resistance to these furan compounds.Thus, these strains represent good candidates for future studies of genetic variation relevant to understanding and manipulating furfural resistance and in the development of tolerant ethanologenic yeast strains for use in bioethanol production from lignocellulose processing.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of East Anglia, Norwich, NR4 7JN UK.

ABSTRACT

Background: Fermentation of bioethanol using lignocellulosic biomass as a raw material provides a sustainable alternative to current biofuel production methods by utilising waste food streams as raw material. Before lignocellulose can be fermented, it requires physical, chemical and enzymatic treatment in order to release monosaccharides, a process that causes the chemical transformation of glucose and xylose into the cyclic aldehydes furfural and hydroxyfurfural. These furan compounds are potent inhibitors of Saccharomyces fermentation, and consequently furfural tolerant strains of Saccharomyces are required for lignocellulosic fermentation.

Results: This study investigated yeast tolerance to furfural and hydroxyfurfural using a collection of 71 environmental and industrial isolates of the baker's yeast Saccharomyces cerevisiae and its closest relative Saccharomyces paradoxus. The Saccharomyces strains were initially screened for growth on media containing 100 mM glucose and 1.5 mg ml(-1) furfural. Five strains were identified that showed a significant tolerance to growth in the presence of furfural, and these were then screened for growth and ethanol production in the presence of increasing amounts (0.1 to 4 mg ml(-1)) of furfural.

Conclusions: Of the five furfural tolerant strains, S. cerevisiae National Collection of Yeast Cultures (NCYC) 3451 displayed the greatest furfural resistance and was able to grow in the presence of up to 3.0 mg ml(-1) furfural. Furthermore, ethanol production in this strain did not appear to be inhibited by furfural, with the highest ethanol yield observed at 3.0 mg ml(-1) furfural. Although furfural resistance was not found to be a trait specific to any one particular lineage or population, three of the strains were isolated from environments where they might be continually exposed to low levels of furfural through the ongoing natural degradation of lignocelluloses, and would therefore develop elevated levels of resistance to these furan compounds. Thus, these strains represent good candidates for future studies of genetic variation relevant to understanding and manipulating furfural resistance and in the development of tolerant ethanologenic yeast strains for use in bioethanol production from lignocellulose processing.

No MeSH data available.


Related in: MedlinePlus

Growth curves ofSaccharomycesstrains grown in yeast nutrient broth containing 100 mM glucose and furfural. Data shown are the average of three replicate experiments. (A)S. cerevisiae NCYC 2826, (B)S. paradoxus NCYC 3277, (C)S. cerevisiae NCYC 3312, (D)S. cerevisiae NCYC 3290, (E)S. cerevisiae NCYC 3284 and (F)S. cerevisiae NCYC 3451. Media was supplemented with furfural at concentrations of 0.1 (squares), 0.5 (circles), 1.0 (triangles), 1.5 (diamonds), 2.0 (open squares), 2.5 (open circles), 3.0 (diamonds), 3.5 (open triangles) and 4.0 mg ml−1 furfural (crosses). OD, optical density; hr, hour.
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Fig3: Growth curves ofSaccharomycesstrains grown in yeast nutrient broth containing 100 mM glucose and furfural. Data shown are the average of three replicate experiments. (A)S. cerevisiae NCYC 2826, (B)S. paradoxus NCYC 3277, (C)S. cerevisiae NCYC 3312, (D)S. cerevisiae NCYC 3290, (E)S. cerevisiae NCYC 3284 and (F)S. cerevisiae NCYC 3451. Media was supplemented with furfural at concentrations of 0.1 (squares), 0.5 (circles), 1.0 (triangles), 1.5 (diamonds), 2.0 (open squares), 2.5 (open circles), 3.0 (diamonds), 3.5 (open triangles) and 4.0 mg ml−1 furfural (crosses). OD, optical density; hr, hour.

Mentions: Figure 3 shows growth in the presence of varying amounts of furfural (0.1 to 4.0 mg ml−1) for S. cerevisiae strains NCYC 3284, NCYC 3290, NCYC 3312 and NCYC 3451 and S. paradoxus strain NCYC 3277 identified in Table 1 from the SGRP strain set as having increased resistance to furfural. Additional file 1: Figure S1 shows the corresponding growth data plotted on a log scale. The control strain S. cerevisiae NCYC 2826 was also included for comparative purposes. For all six strains, as furfural concentration increased the growth curves begin to show increases in the lag phase as previously seen in growths containing furfural. All strains tested were able to grow on YNB supplemented with 100 mM glucose and 0.1 to 1.5 mg ml−1 furfural. S. cerevisiae NCYC 2826, our control strain, was only able to grow on up to 1.5 mg ml−1, which led to a 30% reduction in final OD when compared to growth on 0.1 mg ml−1 furfural. Table 2 shows that the ethanol production by NCYC 2826 under these conditions was considerably reduced compared to the approximately 90% yield observed when grown on YNB and glucose alone or on wheat straw hydrolysate. S. cerevisiae NCYC 2826 was isolated from grape must and so is unlikely to have evolved the ability to grow and ferment during exposure to furfural.Figure 3


Identification of furfural resistant strains of Saccharomyces cerevisiae and Saccharomyces paradoxus from a collection of environmental and industrial isolates.

Field SJ, Ryden P, Wilson D, James SA, Roberts IN, Richardson DJ, Waldron KW, Clarke TA - Biotechnol Biofuels (2015)

Growth curves ofSaccharomycesstrains grown in yeast nutrient broth containing 100 mM glucose and furfural. Data shown are the average of three replicate experiments. (A)S. cerevisiae NCYC 2826, (B)S. paradoxus NCYC 3277, (C)S. cerevisiae NCYC 3312, (D)S. cerevisiae NCYC 3290, (E)S. cerevisiae NCYC 3284 and (F)S. cerevisiae NCYC 3451. Media was supplemented with furfural at concentrations of 0.1 (squares), 0.5 (circles), 1.0 (triangles), 1.5 (diamonds), 2.0 (open squares), 2.5 (open circles), 3.0 (diamonds), 3.5 (open triangles) and 4.0 mg ml−1 furfural (crosses). OD, optical density; hr, hour.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4389715&req=5

Fig3: Growth curves ofSaccharomycesstrains grown in yeast nutrient broth containing 100 mM glucose and furfural. Data shown are the average of three replicate experiments. (A)S. cerevisiae NCYC 2826, (B)S. paradoxus NCYC 3277, (C)S. cerevisiae NCYC 3312, (D)S. cerevisiae NCYC 3290, (E)S. cerevisiae NCYC 3284 and (F)S. cerevisiae NCYC 3451. Media was supplemented with furfural at concentrations of 0.1 (squares), 0.5 (circles), 1.0 (triangles), 1.5 (diamonds), 2.0 (open squares), 2.5 (open circles), 3.0 (diamonds), 3.5 (open triangles) and 4.0 mg ml−1 furfural (crosses). OD, optical density; hr, hour.
Mentions: Figure 3 shows growth in the presence of varying amounts of furfural (0.1 to 4.0 mg ml−1) for S. cerevisiae strains NCYC 3284, NCYC 3290, NCYC 3312 and NCYC 3451 and S. paradoxus strain NCYC 3277 identified in Table 1 from the SGRP strain set as having increased resistance to furfural. Additional file 1: Figure S1 shows the corresponding growth data plotted on a log scale. The control strain S. cerevisiae NCYC 2826 was also included for comparative purposes. For all six strains, as furfural concentration increased the growth curves begin to show increases in the lag phase as previously seen in growths containing furfural. All strains tested were able to grow on YNB supplemented with 100 mM glucose and 0.1 to 1.5 mg ml−1 furfural. S. cerevisiae NCYC 2826, our control strain, was only able to grow on up to 1.5 mg ml−1, which led to a 30% reduction in final OD when compared to growth on 0.1 mg ml−1 furfural. Table 2 shows that the ethanol production by NCYC 2826 under these conditions was considerably reduced compared to the approximately 90% yield observed when grown on YNB and glucose alone or on wheat straw hydrolysate. S. cerevisiae NCYC 2826 was isolated from grape must and so is unlikely to have evolved the ability to grow and ferment during exposure to furfural.Figure 3

Bottom Line: Furthermore, ethanol production in this strain did not appear to be inhibited by furfural, with the highest ethanol yield observed at 3.0 mg ml(-1) furfural.Although furfural resistance was not found to be a trait specific to any one particular lineage or population, three of the strains were isolated from environments where they might be continually exposed to low levels of furfural through the ongoing natural degradation of lignocelluloses, and would therefore develop elevated levels of resistance to these furan compounds.Thus, these strains represent good candidates for future studies of genetic variation relevant to understanding and manipulating furfural resistance and in the development of tolerant ethanologenic yeast strains for use in bioethanol production from lignocellulose processing.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of East Anglia, Norwich, NR4 7JN UK.

ABSTRACT

Background: Fermentation of bioethanol using lignocellulosic biomass as a raw material provides a sustainable alternative to current biofuel production methods by utilising waste food streams as raw material. Before lignocellulose can be fermented, it requires physical, chemical and enzymatic treatment in order to release monosaccharides, a process that causes the chemical transformation of glucose and xylose into the cyclic aldehydes furfural and hydroxyfurfural. These furan compounds are potent inhibitors of Saccharomyces fermentation, and consequently furfural tolerant strains of Saccharomyces are required for lignocellulosic fermentation.

Results: This study investigated yeast tolerance to furfural and hydroxyfurfural using a collection of 71 environmental and industrial isolates of the baker's yeast Saccharomyces cerevisiae and its closest relative Saccharomyces paradoxus. The Saccharomyces strains were initially screened for growth on media containing 100 mM glucose and 1.5 mg ml(-1) furfural. Five strains were identified that showed a significant tolerance to growth in the presence of furfural, and these were then screened for growth and ethanol production in the presence of increasing amounts (0.1 to 4 mg ml(-1)) of furfural.

Conclusions: Of the five furfural tolerant strains, S. cerevisiae National Collection of Yeast Cultures (NCYC) 3451 displayed the greatest furfural resistance and was able to grow in the presence of up to 3.0 mg ml(-1) furfural. Furthermore, ethanol production in this strain did not appear to be inhibited by furfural, with the highest ethanol yield observed at 3.0 mg ml(-1) furfural. Although furfural resistance was not found to be a trait specific to any one particular lineage or population, three of the strains were isolated from environments where they might be continually exposed to low levels of furfural through the ongoing natural degradation of lignocelluloses, and would therefore develop elevated levels of resistance to these furan compounds. Thus, these strains represent good candidates for future studies of genetic variation relevant to understanding and manipulating furfural resistance and in the development of tolerant ethanologenic yeast strains for use in bioethanol production from lignocellulose processing.

No MeSH data available.


Related in: MedlinePlus