The immobilization of Saccharomyces cerevisiae DSM 70424, Saccharomyces ludwigii DSM 3447 and Saccharomyces rouxii DSM 2531 on brewer's spent grain and then ethanol production and sugar consumption of these immobilized yeasts were investigated. The aim of this study was to investigate the abilities of these three immobilized yeasts for producing alcohol for brewing at two temperatures (7 and 12 °C) using two different sugar levels (one at original level supplied in the brewery and one with 2.5% (w/v), added glucose to the wort). Increasing both parameters resulted in higher alcohol production by all the yeasts studied. At 7 °C and with original wort density the ethanol content at the end of fermentation was 2.7% (v/v) for S. cerevisiae, 1.7% for S. ludwigii and 2.0% for S. rouxii. After the addition of 2.5% (w/v) glucose at the same temperature (7 °C), the alcohol production was increased to 4.1, 2.8 and 4.1%, respectively. Similar improvements were observed when the fermentation was carried out at 12 °C with/without the addition of glucose to the wort. However, temperature indicated greater influence on S. ludwigii than did on S. rouxii and S. cerevisiae. The immobilization as carried out in this study impacted both S. ludwigii and S. rouxii in a way that they could consume maltose under certain conditions.
Brewer's spent grain; Fermentation; Immobilization; Saccharomyces cerevisiae; Saccharomyces ludwigii; Saccharomyces rouxii
