Fermentation characteristics as criteria for selection of cachaca yeast

The fermentation characteristics of 24 strains of Saccharomyces cerevisiae and one strain of Candida apicola, C. famata, C. guilliermondii, Hanseniospora occidentalis, Pichia subpelicullosa and Schizosaccharomyces pombe were evaluated for the production of cachac, a. They were isolated from small cachac, a distilleries ( 27), industrial cachac, a distilleries ( 2) and one sugarcane alcohol distillery. The yeasts showed significant differences in ethanol yield, substrate conversion, efficiency, conversion factors of substrate into ethanol (Y-p/s), cells (Y-x/s), organic acids (Y-ac/s) and glycerol (Y-g/s), and maximum specific growth rate (mu(max)). In general the S. cerevisiae strains showed better fermentation potential, with yields between 83 and 91% and mu(max) between 0.450 and 0.640 h(-1), several of them being comparable with the high performance yeast used in the industrial production of ethanol, which was adopted as a reference. The non-Saccharomyces strains showed high efficiency, very low ethanol yield and very high Y-ac/s and Y-g/s values, except Pichia subpelliculosa, which behaved very similarly to the S. cerevisiae strains. Hierarchical Cluster Analysis and Principal Component Analysis showed the fermentation yield ( or substrate conversion) as being the variable which contributed most to the separation of the strains into different groups.