Membrane Fouling during Constant Flux Crossflow Microfiltration of Dilute Suspensions of Active Dry Yeast

Abstract

Abstract Fouling of microporous and ultrafiltration membranes during crossflow microfiltration of rehydrated active dry yeast (ADY) was investigated using measurements of the transmembrane pressure as a function of time at constant flux. By centrifuging the suspensions and comparing the increase in transmembrane pressure produced by both the original suspensions and the supernatant alone, it was determined that this increase was mainly caused by soluble components in the supernatant. This finding is consistent with previous observations that considerable quantities of intracellular matter leak from cells of ADY when they are rehydrated. The increase in transmembrane pressure caused by the supernatant alone was found to be independent of tangential flow rate. suggesting that the underlying mechanism was one of internal membrane fouling. Fouling was found to be enhanced by increasing the transmembrane flux and reducing the membrane pore size. Membrane fouling by the supernatant was modeled as a process invo...