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Shifting the fermentative/oxidative balance in Saccharomyces cerevisiae by transcriptional deregulation of Snf1 via overexpression of the upstream activating kinase Sak1p.
Appl Environ Microbiol. 2011 Mar; 77(6):1981-9.AE

Abstract

With the aim to reduce fermentation by-products and to promote respiratory metabolism by shifting the fermentative/oxidative balance, we evaluated the constitutive overexpression of the SAK1 and HAP4 genes in Saccharomyces cerevisiae. Sak1p is one of three kinases responsible for the phosphorylation, and thereby the activation, of the Snf1p complex, while Hap4p is the activator subunit of the Hap2/3/4/5 transcriptional complex. We compared the physiology of a SAK1-overexpressing strain with that of a strain overexpressing the HAP4 gene in wild-type and sdh2 deletion (respiratory-deficient) backgrounds. Both SAK1 and HAP4 overexpressions led to the upregulation of glucose-repressed genes and to reduced by-product formation rates (ethanol and glycerol). SAK1 overexpression had a greater impact on growth rates than did HAP4 overexpression. Elevated transcript levels of SAK1, but not HAP4, resulted in increased biomass yields in batch cultures grown on glucose (aerobic and excess glucose) as well as on nonfermentable carbon sources. SAK1 overexpression, but not the combined overexpression of SAK1 and HAP4 or the overexpression of HAP4 alone, restored growth on ethanol in an sdh2 deletion strain. In glucose-grown shake flask cultures, the sdh2 deletion strain with SAK1 and HAP4 overexpression produced succinic acid at a titer of 8.5 g liter(-1) and a yield of 0.26 mol (mol glucose)(-1) within 216 h. We here report for the first time that a constitutively high level of expression of SAK1 alleviates glucose repression and shifts the fermentative/oxidative balance under both glucose-repressed and -derepressed conditions.

Authors+Show Affiliations

Berlin University of Technology, Institute for Biotechnology, Department of Microbiology and Genetics, Gustav Meyer Allee 25, D-13355 Berlin, Germany.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21257817

Citation

Raab, Andreas M., et al. "Shifting the Fermentative/oxidative Balance in Saccharomyces Cerevisiae By Transcriptional Deregulation of Snf1 Via Overexpression of the Upstream Activating Kinase Sak1p." Applied and Environmental Microbiology, vol. 77, no. 6, 2011, pp. 1981-9.
Raab AM, Hlavacek V, Bolotina N, et al. Shifting the fermentative/oxidative balance in Saccharomyces cerevisiae by transcriptional deregulation of Snf1 via overexpression of the upstream activating kinase Sak1p. Appl Environ Microbiol. 2011;77(6):1981-9.
Raab, A. M., Hlavacek, V., Bolotina, N., & Lang, C. (2011). Shifting the fermentative/oxidative balance in Saccharomyces cerevisiae by transcriptional deregulation of Snf1 via overexpression of the upstream activating kinase Sak1p. Applied and Environmental Microbiology, 77(6), 1981-9. https://doi.org/10.1128/AEM.02219-10
Raab AM, et al. Shifting the Fermentative/oxidative Balance in Saccharomyces Cerevisiae By Transcriptional Deregulation of Snf1 Via Overexpression of the Upstream Activating Kinase Sak1p. Appl Environ Microbiol. 2011;77(6):1981-9. PubMed PMID: 21257817.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Shifting the fermentative/oxidative balance in Saccharomyces cerevisiae by transcriptional deregulation of Snf1 via overexpression of the upstream activating kinase Sak1p. AU - Raab,Andreas M, AU - Hlavacek,Verena, AU - Bolotina,Natalia, AU - Lang,Christine, Y1 - 2011/01/21/ PY - 2011/1/25/entrez PY - 2011/1/25/pubmed PY - 2011/6/23/medline SP - 1981 EP - 9 JF - Applied and environmental microbiology JO - Appl Environ Microbiol VL - 77 IS - 6 N2 - With the aim to reduce fermentation by-products and to promote respiratory metabolism by shifting the fermentative/oxidative balance, we evaluated the constitutive overexpression of the SAK1 and HAP4 genes in Saccharomyces cerevisiae. Sak1p is one of three kinases responsible for the phosphorylation, and thereby the activation, of the Snf1p complex, while Hap4p is the activator subunit of the Hap2/3/4/5 transcriptional complex. We compared the physiology of a SAK1-overexpressing strain with that of a strain overexpressing the HAP4 gene in wild-type and sdh2 deletion (respiratory-deficient) backgrounds. Both SAK1 and HAP4 overexpressions led to the upregulation of glucose-repressed genes and to reduced by-product formation rates (ethanol and glycerol). SAK1 overexpression had a greater impact on growth rates than did HAP4 overexpression. Elevated transcript levels of SAK1, but not HAP4, resulted in increased biomass yields in batch cultures grown on glucose (aerobic and excess glucose) as well as on nonfermentable carbon sources. SAK1 overexpression, but not the combined overexpression of SAK1 and HAP4 or the overexpression of HAP4 alone, restored growth on ethanol in an sdh2 deletion strain. In glucose-grown shake flask cultures, the sdh2 deletion strain with SAK1 and HAP4 overexpression produced succinic acid at a titer of 8.5 g liter(-1) and a yield of 0.26 mol (mol glucose)(-1) within 216 h. We here report for the first time that a constitutively high level of expression of SAK1 alleviates glucose repression and shifts the fermentative/oxidative balance under both glucose-repressed and -derepressed conditions. SN - 1098-5336 UR - https://www.unboundmedicine.com/medline/citation/21257817/Shifting_the_fermentative/oxidative_balance_in_Saccharomyces_cerevisiae_by_transcriptional_deregulation_of_Snf1_via_overexpression_of_the_upstream_activating_kinase_Sak1p_ L2 - https://journals.asm.org/doi/10.1128/AEM.02219-10?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -