Cross-flow membrane filtration of yeast suspensions

Abstract The feasibility of harvesting yeast cells using synthetic membranes was studied. Three cross-flow membrane filters were compared in terms of flux and cell yields: a pleated-sheet microfilter, a tubular microfilter and a hollow fiber ultrafiltration module. Flux declined in an exponential manner with time with all three modules. In general, lower fouling rates were observed at lower cell concentrations, lower transmembrane pressures and higher velocity. Media components played a relatively greater role in the fouling phenomenon at low cell concentrations. The ultrafiltration module had much lower fouling rates than the microfilters. The pleated-sheet microfilter experienced rapid plugging, significant cell loss and considerably greater difficulty in cleaning. In contrast, the other membrane modules showed almost quantitative cell recoveries. The flux of the tubular microfilter was more than 100 L m −2 h −1 (LMH) at yeast cell concentrations of 100 g L −1 , while the hollow fibers had a flux of 40 LMH at 250 g L −1 .