000 03403nma a2200301 4500
008 2013 eng
022 _a1098-5336
040 _cscwl
041 _aeng
100 0 _aClark M. Henderson.
245 1 0 _aEthanol Production and Maximum Cell Growth Are Highly Correlated with Membrane Lipid Composition during Fermentation as Determined by Lipidomic Analysis of 22 Saccharomyces cerevisiae Strains /
_cby Clark M. Henderson.
260 _bAmerican Society for Microbiology,
300 _bJournal article
490 0 _aApplied and Environmental Microbiology
520 _aOptimizing ethanol yield during fermentation is important for efficient production of fuel alcohol, as well as wine and other alcoholic beverages. However, increasing ethanol concentrations during fermentation can create problems that result in arrested or sluggish sugar-to-ethanol conversion. The fundamental cellular basis for these problem fermentations, however, is not well understood. Small-scale fermentations were performed in a synthetic grape must using 22 industrial Saccharomyces cerevisiae strains (primarily wine strains) with various degrees of ethanol tolerance to assess the correlation between lipid composition and fermentation kinetic parameters. Lipids were extracted at several fermentation time points representing different growth phases of the yeast to quantitatively analyze phospholipids and ergosterol utilizing atmospheric pressure ionization-mass spectrometry methods. Lipid profiling of individual fermentations indicated that yeast lipid class profiles do not shift dramatically in composition over the course of fermentation. Multivariate statistical analysis of the data was performed using partial least-squares linear regression modeling to correlate lipid composition data with fermentation kinetic data. The results indicate a strong correlation (R2 = 0.91) between the overall lipid composition and the final ethanol concentration (wt/wt), an indicator of strain ethanol tolerance. One potential component of ethanol tolerance, the maximum yeast cell concentration, was also found to be a strong function of lipid composition (R2 = 0.97). Specifically, strains unable to complete fermentation were associated with high phosphatidylinositol levels early in fermentation. Yeast strains that achieved the highest cell densities and ethanol concentrations were positively correlated with phosphatidylcholine species similar to those known to decrease the perturbing effects of ethanol in model membrane systems.
700 0 _aDavid E. Block.
700 0 _aVladimir Jiranek.
700 0 _aMichelle Lozada-Contreras.
700 0 _aMarjorie L. Longo.
710 2 _adSchool of Agriculture, Food, and Wine, The University of Adelaide, Glen Osmond, South Australia, Australia.
710 2 _aaBiophysics Graduate Group.
710 2 _abDepartment of Viticulture and Enology.
710 2 _acDepartment of Chemical Engineering and Materials Science, University of California, Davis, California, USA.
773 0 _tApplied and Environmental Microbiology.
_g(Vol.) 79. (No.) 1. 2013. (Pages.) 91-104.
856 4 2 _uhttp://aem.asm.org/content/79/1/91.abstract
_yLink to original article.
991 _aAEM
_bApplied and Environmental Microbiology
999 _c45890