POTENCIALIDADES DE LINHAGENS DE LEVEDURA Saccharomyces cerevisiae PARA A FERMENTAÇÃO DO CALDO DE CANA

Abstract

Três linhagens de levedura da espécie Saccharomyces cerevisiae, sendo duas floculantes, das quais uma não produtora de sulfeto de hidrogênio, foram avaliadas para se verificar seus desempenhos, sob parâmetros cinéticos, bem como a formação de compostos secundários na fermentação do caldo de cana-de-açúcar, destinado à produção de aguardente. O acompanhamento da cinética fermentativa mostrou melhores resultados de eficiência de fermentação, fator de conversão de substrato em etanol e velocidade específica de crescimento pela linhagem floculante IZ 987, que foram de 89,9%, 0,46 g.g-1 e 0,0996 h-1 respectivamente. Esta linhagem foi também responsável pela maior produção de álcoois superiores, 185 mg.L-1, inerente à sua característica de não produzir H2S. A melhor produtividade de fermentação, de 3,40 g.L-1.h-1, foi a obtida pela linhagem floculante LF. A linhagem FP, não floculante, isolada à partir do fermento prensado, proporcionou os menores valores dos parâmetros cinéticos estudados.

Biochemical and Molecular Characterization ofSaccharomyces cerevisiaeStrains Obtained from Sugar-Cane Juice Fermentations and Their Impact in Cachaça Production

“…The 500 isolates were tested for the capacity to produce H 2 S, an undesirable compound associated with an off-flavor and unpleasant taste, that must be absent from fermented beverages (37). From the initial set of isolates, H 2 S-producing strains were excluded, and the remaining yeasts were tested for cellular growth at different ethanol concentrations (10, 15, and 20% [wt/vol]) at 37°C.…”

“…Our strategy also included strains with additional characteristics that are considered desirable, namely, a high fermentative power, here estimated "potentially" in terms of invertase activity (13,52); the absence of H 2 S production, since this compound is considered an off flavor (37); killer activity, in order to guarantee the efficient elimination of competitors (6,29,31,48); flocculation ability, to separate the yeast biomass from the fermented juice at the end of the process; and the production of high levels of flavoring compounds, such as higher alcohols and esters.…”

Isolation and characterization of Saccharomyces cerevisiae strains of winery interest

“…The flocculation is an important characteristic that allows an easy separation of the final product at the end of the fermentation without additional filtration/ centrifugation steps and also allows the utilization of immobilized yeasts on fermentation processes (Stratford, 1992). Only one isolate showed the flocculation ability as observed on Table V. Yeasts with a elevate production of hydrogen sulfide are undesirable for wine production because confer flavor and taste that compromise the quality of the wine obtained (Ribeiro, Horii, 1999). Thus the yeasts were tested for hydrogen sulfide production (Table V and Figure 2).…”

Fermentation capacity of Saccharomyces cerevisiae cultures

“…Reports mentioning that different samples of the same species could have different physiological characteristics, among them the fermentative capacity, have been described by Jones et al (1981); Kreger-van Rij (1984); Souza andQueiroz, 1995. Ribeiro andHorii (1999), studying three strains of S. cerevisiae to evaluate their performance on ethanol fermentation, observed that the best productivity (3.40 g.L -1 .h -1 ) was presented by the IZ-987 flocculent strain. Gomes et al (2004) used three strains of S. cerevisiae to study the optimization of the fermentative process, aiming to evaluate the kinetic parameters of fermentation and observed that the UFMG-A 1007 strain presented better values regarding productivity; however, the UFMG-A 907 strain presented the best results regarding fermentative parameters.…”