Malolactic fermentation in chardonnay wine by immobilised Lactobacillus casei cells

Abstract

The kinetics of malolactic fermentation in Chardonnay wine by immobilised Lactobacillus casei cells has been studied. Calcium pectate gel and chemically modified chitosan beads were used as supports for immobilisation. Repeated batch fermentations were carried out with different wine samples, some of which were treated with sulfur dioxide (free 19–25 mg/litre and total 80–88 mg/litre), in shake flask at 36, 25 and 20°C without any loss of activity. The degradation of malic acid obtained using immobilised cells was twice as high as that obtained with free cells. At an initial pH 3·2, decrease of malic acid of about 30% was observed at 25°C in one hour using L. casei cells immobilised either in pectate gel or on chitosan. Among the physico-chemical parameters studied, temperature was the main factor affecting metabolism of the organic acids as well as the rate of the malolactic fermentation. Operational stability of calcium pectate gel beads and chemically modified chitosan beads was 6 months after eight fermentations and 2 months after five fermentations, respectively, which proved the possibility of industrial application of the chosen supports in wine making.