No abstract

The continuous making of wine by a delignified cellulosic (DC) material-supported biocatalyst is reported. It was prepared by immobilizing the alcohol resistant strain AXAZ-1 on DC material. The product was found suitable for the continuous process in industrial applications. The operational stability was maintained for 2 mo with monitoring the ethanol concentration, wine, and alcohol productivities as well as the stability of oBe density at the outlet. Wine productivity was three- to sixfold higher than obtained by natural fermentation, alcohol concentrations of the wine was in the range of 9.3-11.2% v/v and low volatile acidities of 0.15-0.36 g acetic acid/L were obtained. The effect of total acidity and flow rate of must were also examined. To demonstrate that the operational stability of the bioreactor is due to DC material that promotes the fermentation, and it takes place at even higher ethanol levels, an analogous system of kissiris supported biocatalyst was studied. Likewise, the tolerance in the alcohol concentration, as compared with free cells, were studied by their stability of the activity in the repeated batch fermentation of must.

Using gamma-alumina pellets, more than threefold increase of the ethanol productivity in the fermentation molasse has been obtained in the present work. Also, molasse fermentation in the presence of gamma-alumina gave 78.4 g/L ethanol, ethanol yield factor 0.44 g/g, and conversion 89.4% at initial sugar concentration (ISC) 179.5 g/L, compared to 53.9 g/L, 0.30 g/g and 62.7% in its absence, respectively. Furthermore, it was found that gamma-alumina reduces the activation energy Ea of fermentation. This inorganic material does not promote the fermentation of raisin extract.