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Expression of Mitochondrial Cytochrome C Oxidase Chaperone Gene (COX20) Improves Tolerance to Weak Acid and Oxidative Stress during Yeast Fermentation.

Kumar V, Hart AJ, Keerthiraju ER, Waldron PR, Tucker GA, Greetham D - PLoS ONE (2015)

Bottom Line: Saccharomyces cerevisiae is the micro-organism of choice for the conversion of fermentable sugars released by the pre-treatment of lignocellulosic material into bioethanol.Pre-treatment of lignocellulosic material releases acetic acid and previous work identified a cytochrome oxidase chaperone gene (COX20) which was significantly up-regulated in yeast cells in the presence of acetic acid.This is a study which has utilised tetracycline-regulated protein expression in a fermentation system, which was characterised by improved (or enhanced) tolerance to acetic acid and oxidative stress.

View Article: PubMed Central - PubMed

Affiliation: University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom.

ABSTRACT

Introduction: Saccharomyces cerevisiae is the micro-organism of choice for the conversion of fermentable sugars released by the pre-treatment of lignocellulosic material into bioethanol. Pre-treatment of lignocellulosic material releases acetic acid and previous work identified a cytochrome oxidase chaperone gene (COX20) which was significantly up-regulated in yeast cells in the presence of acetic acid.

Results: A Δcox20 strain was sensitive to the presence of acetic acid compared with the background strain. Overexpressing COX20 using a tetracycline-regulatable expression vector system in a Δcox20 strain, resulted in tolerance to the presence of acetic acid and tolerance could be ablated with addition of tetracycline. Assays also revealed that overexpression improved tolerance to the presence of hydrogen peroxide-induced oxidative stress.

Conclusion: This is a study which has utilised tetracycline-regulated protein expression in a fermentation system, which was characterised by improved (or enhanced) tolerance to acetic acid and oxidative stress.

No MeSH data available.


Related in: MedlinePlus

Growth rates for Δcox20 pCM173 and Δcox20 pCM173(COX20) under control conditions (4% glucose) and 25–75 mM acetic acid (A) Δcox20 pCM173 and (B) Δcox20 pCM173(COX20).Results presented are a representative of triplicate values (Mean +/- SD n = 3).
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pone.0139129.g004: Growth rates for Δcox20 pCM173 and Δcox20 pCM173(COX20) under control conditions (4% glucose) and 25–75 mM acetic acid (A) Δcox20 pCM173 and (B) Δcox20 pCM173(COX20).Results presented are a representative of triplicate values (Mean +/- SD n = 3).

Mentions: The growth of yeast strains overexpressing COX20 was determined in the presence of acetic acid and compared with the empty vector control. Yeast strains containing pCM173 or pCM173(COX20) had similar growth curves under control conditions (Fig 4A and 4B), however; addition of 25–75 mM acetic acid slowed growth of a yeast strain containing an empty pCM173 vector when compared with a strain containing a pCM173(COX20) vector (Fig 4A and 4B). An assessment of half maximal inhibitory concentration (IC50) for acetic acid on growth revealed that Δcox20 and a Δcox20 (pCM173) strain had IC50s of 76 ± 0.12 and 77.5 ± 0.26 mM respectively, wild-type (BY4741) had an IC50 value of 83 ± 1.15 mM and a Δcox20 (pCM173) had an IC50 value of 98.5 ± 0.9 mM respectively.


Expression of Mitochondrial Cytochrome C Oxidase Chaperone Gene (COX20) Improves Tolerance to Weak Acid and Oxidative Stress during Yeast Fermentation.

Kumar V, Hart AJ, Keerthiraju ER, Waldron PR, Tucker GA, Greetham D - PLoS ONE (2015)

Growth rates for Δcox20 pCM173 and Δcox20 pCM173(COX20) under control conditions (4% glucose) and 25–75 mM acetic acid (A) Δcox20 pCM173 and (B) Δcox20 pCM173(COX20).Results presented are a representative of triplicate values (Mean +/- SD n = 3).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591339&req=5

pone.0139129.g004: Growth rates for Δcox20 pCM173 and Δcox20 pCM173(COX20) under control conditions (4% glucose) and 25–75 mM acetic acid (A) Δcox20 pCM173 and (B) Δcox20 pCM173(COX20).Results presented are a representative of triplicate values (Mean +/- SD n = 3).
Mentions: The growth of yeast strains overexpressing COX20 was determined in the presence of acetic acid and compared with the empty vector control. Yeast strains containing pCM173 or pCM173(COX20) had similar growth curves under control conditions (Fig 4A and 4B), however; addition of 25–75 mM acetic acid slowed growth of a yeast strain containing an empty pCM173 vector when compared with a strain containing a pCM173(COX20) vector (Fig 4A and 4B). An assessment of half maximal inhibitory concentration (IC50) for acetic acid on growth revealed that Δcox20 and a Δcox20 (pCM173) strain had IC50s of 76 ± 0.12 and 77.5 ± 0.26 mM respectively, wild-type (BY4741) had an IC50 value of 83 ± 1.15 mM and a Δcox20 (pCM173) had an IC50 value of 98.5 ± 0.9 mM respectively.

Bottom Line: Saccharomyces cerevisiae is the micro-organism of choice for the conversion of fermentable sugars released by the pre-treatment of lignocellulosic material into bioethanol.Pre-treatment of lignocellulosic material releases acetic acid and previous work identified a cytochrome oxidase chaperone gene (COX20) which was significantly up-regulated in yeast cells in the presence of acetic acid.This is a study which has utilised tetracycline-regulated protein expression in a fermentation system, which was characterised by improved (or enhanced) tolerance to acetic acid and oxidative stress.

View Article: PubMed Central - PubMed

Affiliation: University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom.

ABSTRACT

Introduction: Saccharomyces cerevisiae is the micro-organism of choice for the conversion of fermentable sugars released by the pre-treatment of lignocellulosic material into bioethanol. Pre-treatment of lignocellulosic material releases acetic acid and previous work identified a cytochrome oxidase chaperone gene (COX20) which was significantly up-regulated in yeast cells in the presence of acetic acid.

Results: A Δcox20 strain was sensitive to the presence of acetic acid compared with the background strain. Overexpressing COX20 using a tetracycline-regulatable expression vector system in a Δcox20 strain, resulted in tolerance to the presence of acetic acid and tolerance could be ablated with addition of tetracycline. Assays also revealed that overexpression improved tolerance to the presence of hydrogen peroxide-induced oxidative stress.

Conclusion: This is a study which has utilised tetracycline-regulated protein expression in a fermentation system, which was characterised by improved (or enhanced) tolerance to acetic acid and oxidative stress.

No MeSH data available.


Related in: MedlinePlus