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Strategy for adapting wine yeasts for bioethanol production.

Ooi BG, Lankford KR - Int J Mol Sci (2009)

Bottom Line: Respiratory-deficient mutants resistant to 500 microg/mL lycorine were isolated.Two mutants, 71B-1122 YEBr L3 and K1-V1116 YEBr L4, were shown to achieve about 10% and 18% improvement in their glucose-to-ethanol conversion efficiency compared to their respective parent strains.The K1-V1116 YEBr L4 in particular can tolerate an ethanol yield of 18.8 +/- 0.8% at 3.5 weeks of fermentation and continued to consume most of the sugar until less than 1% glucose was left.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN 37132, USA. bgooi@mtsu.edu

ABSTRACT
The Saccharomyces cerevisiae wine yeast strains 71B-1122 and K1-V1116 were used to derive strains that could tolerate and produce higher ethanol yields. Respiratory-deficient mutants resistant to 500 microg/mL lycorine were isolated. Two mutants, 71B-1122 YEBr L3 and K1-V1116 YEBr L4, were shown to achieve about 10% and 18% improvement in their glucose-to-ethanol conversion efficiency compared to their respective parent strains. The K1-V1116 YEBr L4 in particular can tolerate an ethanol yield of 18.8 +/- 0.8% at 3.5 weeks of fermentation and continued to consume most of the sugar until less than 1% glucose was left.

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Flow chart of the culture method using ethidium bromide to induce yeast mutation.
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f1-ijms-10-00385: Flow chart of the culture method using ethidium bromide to induce yeast mutation.

Mentions: The wine yeast strains Saccharomyces cerevisiae var. cerevisiae 71B-1122 and K1-V1116 were Lalvin strains purchased from Grape and Granary (Akron, Ohio, USA). Mutants derived from the ethidium bromide mutation method (Figure 1) were designated YEBr and mutants derived using the exposure to ethanol method (Figure 2) were designated MGEt. Those designated with the letter “L” were also resistant to 500 μg/mL lycorine. Minimal media (MM) was prepared with 0.67% Difco yeast nitrogen base without amino acids (Voigt Global Distribution, Lawrence, Kansas, USA). In the minimal media containing 0.2% glucose, the glucose was added after sterilization. The complete media (YEPD) contained 1% yeast extract, 2% Bacto® peptone, 2% glucose and the media plates contain the corresponding media plus 2% granulated agar. The ethidium bromide solution contained 1 mg/mL of ethidium bromide (Sigma-Aldrich, St. Louis, Missouri, USA) dissolved in deionized water that was filtered through a 0.22 μm pore size, 25 mm diameter GE Cameo syringe filter (Fisher Scientific, Fairlawn, New Jersey, USA).


Strategy for adapting wine yeasts for bioethanol production.

Ooi BG, Lankford KR - Int J Mol Sci (2009)

Flow chart of the culture method using ethidium bromide to induce yeast mutation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2662452&req=5

f1-ijms-10-00385: Flow chart of the culture method using ethidium bromide to induce yeast mutation.
Mentions: The wine yeast strains Saccharomyces cerevisiae var. cerevisiae 71B-1122 and K1-V1116 were Lalvin strains purchased from Grape and Granary (Akron, Ohio, USA). Mutants derived from the ethidium bromide mutation method (Figure 1) were designated YEBr and mutants derived using the exposure to ethanol method (Figure 2) were designated MGEt. Those designated with the letter “L” were also resistant to 500 μg/mL lycorine. Minimal media (MM) was prepared with 0.67% Difco yeast nitrogen base without amino acids (Voigt Global Distribution, Lawrence, Kansas, USA). In the minimal media containing 0.2% glucose, the glucose was added after sterilization. The complete media (YEPD) contained 1% yeast extract, 2% Bacto® peptone, 2% glucose and the media plates contain the corresponding media plus 2% granulated agar. The ethidium bromide solution contained 1 mg/mL of ethidium bromide (Sigma-Aldrich, St. Louis, Missouri, USA) dissolved in deionized water that was filtered through a 0.22 μm pore size, 25 mm diameter GE Cameo syringe filter (Fisher Scientific, Fairlawn, New Jersey, USA).

Bottom Line: Respiratory-deficient mutants resistant to 500 microg/mL lycorine were isolated.Two mutants, 71B-1122 YEBr L3 and K1-V1116 YEBr L4, were shown to achieve about 10% and 18% improvement in their glucose-to-ethanol conversion efficiency compared to their respective parent strains.The K1-V1116 YEBr L4 in particular can tolerate an ethanol yield of 18.8 +/- 0.8% at 3.5 weeks of fermentation and continued to consume most of the sugar until less than 1% glucose was left.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN 37132, USA. bgooi@mtsu.edu

ABSTRACT
The Saccharomyces cerevisiae wine yeast strains 71B-1122 and K1-V1116 were used to derive strains that could tolerate and produce higher ethanol yields. Respiratory-deficient mutants resistant to 500 microg/mL lycorine were isolated. Two mutants, 71B-1122 YEBr L3 and K1-V1116 YEBr L4, were shown to achieve about 10% and 18% improvement in their glucose-to-ethanol conversion efficiency compared to their respective parent strains. The K1-V1116 YEBr L4 in particular can tolerate an ethanol yield of 18.8 +/- 0.8% at 3.5 weeks of fermentation and continued to consume most of the sugar until less than 1% glucose was left.

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