PERFORMANCE OF A CELL RECYCLE BUBBLE-COLUMN FERMENTER WITH A MEMBRANE-FILTER MODULE FOR CONTINUOUS VINEGAR PRODUCTION

The steady-state performance of a bubble column combined with a membra ne filter module for cell separation and recycle is investigated numer ically in the case of vinegar fermentation. The one-dimensional disper sion model for describing the longitudinal mixing of the liquid phase is employed. Kinetic expressions and their parameter values are taken from the available literature. Several characteristics of this ferment er system namely the concentration profiles of cells, substrate and pr oduct, the viability of viable cells relative to total cells, the wash out condition for cells and the productivity of acetic acid are discus sed. The average cell viability in the whole column and the critical d ilution rate for washout are presented as equations. Low levels of the axial mixing are found to enhance the vinegar productivity. The optim um dilution rate giving the maximum productivity is determined and bot h are shown as figures with the Peclet number, the recycle ratio and t he bleed ratio as parameters.