A Multistage Bioreactor with Replaceable Bioplates for Continuous Wine Fermentation

Abstract

A horizontal multistage bioreactor with replaceable immobilized plates (bioplates) was constructed for continuous wine fermentation. The bioplates were prepared by immobilizing viable cells in the form of membranes onto sintered glass plates, using calcium alginate as the carrier. Five bioplates were inserted vertically along a rectangular frame constructed from acrylic sheets, thus separating it into six compartments. The residence time distribution curve of the bioreactor approximated that of the six tanks in a series model (j = 5.61). The bioreactor was used for the continuous fermentation of Koshu grape must. During the steady state, axial sugar and ethanol concentration gradients existed from the first to the last compartment. The steady state was maintained for more than 42 days. Also, application of this bioreactor for continuous wine fermentation with simultaneous deacidification of a Muscat Bailey A grape must was carried out. Two bioplates of Schizosaccharomyces pombe O-77 and five bioplates of Saccharomyces cerevisiae 2HY-1 were used to separate the reactor into eight compartments. In this system, the total acidity of the wine during the steady state was reduced by 17% to 38% and the L-malic acid concentration by 58% to 76%. The L-lactic acid concentration remained more or less constant throughout the process.