Strategies to select yeast starters cultures for production of flavor compounds in cachaça fermentations

Abstract

In this work, we have used classical genetics techniques to find improved starter strains to produce cachaça with superior sensorial quality. Our strategy included the selection of yeast strains resistant to 5,5',5″-trifluor-D: ,L: -leucine (TLF) and cerulenin, since these strains produce higher levels of higher alcohols and esters than parental strains. However, no clear relationship was observed when levels of flavoring compounds were compared with the levels expression of the genes (BAT1, BAT2, ATF2, EEB1 genes) involved with the biosynthesis of flavoring compounds. Furthermore, we determined the stability of phenotypes considered as the best indicators of the quality of the cachaça for a parental strain and its segregants. By applying the principal component analysis, a cluster of segregants, showing a high number of characteristics similar to the parental strain, was recognized. One segregant, that was resistant to TLF and cerulenin, also showed growth stability after six consecutive replications on plates containing high concentrations of sugar and ethanol. "Cachaça" produced at laboratory scale using a parental strain and this segregant showed a higher level of flavoring compounds. Both strains predominated in an open fermentative process through seven cycles, as was shown by mitochondrial restriction fragment length polymorphisms analysis. Based on the physical chemical composition of the obtained products, the results demonstrate the usefulness of the developed strategies for the selection of yeast strains to be used as starters in "cachaça" production.

Quality improvement and geographical indication of cachaça (Brazilian spirit) by using locally selected yeast strains

“…Thus, yeast strains used in the fermentative process of cachac ßa production should be resistant to a wide variety of stressful factors. At the same time, the organoleptic characteristics of beverages obtained from the yeast metabolism during fermentation depend mainly on their aromatic compounds' composition (Souza et al 2012). Thus, beyond stressful testing, our selective procedure included the identification of yeast strains able to grow in the presence of TFL and cerulenin to test their potential as producers of flavour compounds, as isoamyl acetate and ethyl caproate respectively (Bussey and Umbarger 1970;Ichikawa et al 1991).…”

Improving industrial yeast strains: exploiting natural and artificial diversity

“…These analogs select for cells with decreased feedback inhibition of amino acid synthesis and increase the production of, respectively, isoamyl alcohol, tyrosol, and β-phenethyl alcohol. Cerulenin, an inhibitor of fatty acid synthesis, is used to select for increased fatty acid synthesis (Ichikawa et al ., 2002; Vicente et al ., 2006; de Souza et al ., 2012), yielding strains with increased ethyl ester production. An increased production of isoamyl acetate (without increasing ethyl acetate production) was achieved by screening for resistance to pregnenolone.…”

New Lager Brewery Strains Obtained by Crossing Techniques Using Cachaça (Brazilian Spirit) Yeasts

“…The yeast strains used in this study were previously isolated from cachaça distilleries according to a methodology described before (19,(38)(39)(40). They are stored in YP broth (1% [wt/vol] yeast extract, 2% [wt/vol] meat peptone) added to 30% (vol/vol) glycerol at Ϫ80°C.…”