Avaliação dos parâmetros cinéticos de Saccharomyces cerevisiae SA-1 em diferentes condições de cultivo em aerobiose

Abstract

The purpose of this work was evaluate the kinetic parameters of the yeast Saccharomyces cerevisiae SA-1 in anaerobic conditions, comparing the use of five different sugars (glucose, fructose, sucrose, galactose and maltose) as single sources of carbon at two different temperatures (32oC and 37oC) to know the physiology of this strains. The strain was stored in YPD (10 g L-1 , yeast extract, 20 g L-1 , peptone and 20 g L-1 glucose, 20 g L-1 agar) being cultivated in mineral as carbon source 10 g L-1 . In parallel, micro and macroscopic analyzes were performed in order to tracing a morphological profile strain. Samplings was made every 30 minutes to obtain a growth curve for determination of the kinetic parameters. The parameters analyzed were specific maximum growth velocity (μmáx), doubling time (TD), maximum biomass concentration (Xmáx) and biomass productivity (PX). Morphologically, S. cerevisiae SA-1 presented surface and smooth edges with an elongated shape. Comparing the cultivations at 32o C and 37oC was possible to infer that at 37oC the lineage showed higher μmáx in all the sources of carbon and less time of cultivation. In glucose, for both temperatures, S. cerevisiae SA-1 presented better adaptation to the substrate, because in these cultures the highest μmax between the substrates used were found, being 0,38 h-1 at 32oC and 0,44 h -1 at 37oC. For Xmáx in glucose and maltose, it was observed a higher biomass production with cultures at 37°C in relation to the cultures at 32°C, as for fructose and sucrose increased production in the cultures at 32°C and for the substrate galactose there was no variation. Analyzing the obtained data, it was observed the best adaptation of the culture with glucose at 37°C, tracing a productive profile in terms of lineage biomass.