Selection of Saccharomyces cerevisiae strains for efficient very high gravity bio-ethanol fermentation processes

Abstract

An optimized very high gravity (VHG) glucose medium supplemented with low cost nutrient sources was used to evaluate bio-ethanol production by 11 Saccharomyces cerevisiae strains. The industrial strains PE-2 and CA1185 exhibited the best overall fermentation performance, producing an ethanol titre of 19.2% (v/v) corresponding to a batch productivity of 2.5 g l(-1) h(-1), while the best laboratory strain (CEN.PK 113-7D) produced 17.5% (v/v) ethanol with a productivity of 1.7 g l(-1) h(-1). The results presented here emphasize the biodiversity found within S. cerevisiae species and that naturally adapted strains, such as PE-2 and CA1185, are likely to play a key role in facilitating the transition from laboratory technological breakthroughs to industrial-scale bio-ethanol fermentations.

Cell recycling during repeated very high gravity bio-ethanol fermentations using the industrial Saccharomyces cerevisiae strain PE-2

“…This strain was previously selected for its high fermentation performance under VHG conditions (Pereira et al 2010b). Stock cultures were maintained on YPD [1% (w/v) yeast extract, 2% (w/v) bacto-peptone and 2% (w/v) glucose] agar plates at 48C.…”

“…PE-2 and CA1185 isolates were selected based on their higher ethanol titre and productivity (Pereira et al 2010b). To gather detailed yeast physiological information of PE-2 and CA1185 isolates in VHG conditions, relevant physiological parameters were measured throughout the different batch fermentation stages and the results reveal their robust physiological background under these intensified fermentation conditions (improved accumulation of trehalose, glycogen and sterols relatively to CEN.PK 113-7D laboratory strain) (Pereira et al 2011).…”

Whole-genome sequencing of the efficient industrial fuel-ethanol fermentative Saccharomyces cerevisiae strain CAT-1

“…We decided to identify sources of genomic variation in the genome of fuel-ethanol yeast strains that might be linked to (and possibly responsible for) important industrial traits. Strain CAT-1 is one of the most common strains used nowadays by the Brazilian fuel-ethanol plants, shows a very efficient fermentation capacity, especially at high sugar concentrations, and has also shown good fermentation characteristics for production of distillates from cereals, when compared with the other fuel-ethanol yeasts (Amorim-Neto et al 2009;Pereira et al 2010). Our analysis of the diploid genome of the S. cerevisiae strain CAT-1 revealed significant structural and sequence variation when compared with the genome of the reference strain S288c, a subset of which is likely associated with traits for prevalence and persistence during bioethanol industrial fermentations.…”

3′ Truncation of the GPD1 Promoter in Saccharomyces cerevisiae for Improved Ethanol Yield and Productivity

“…Generally speaking, laboratory strains are well documented and easy to manipulate. However, laboratory strains are physiologically different from industrial strains (31). For instance, it has been shown that industrial strains produced a significantly higher level of glycerol than did laboratory strains (31)(32)(33).…”