Yeast cell harvesting from cider using microfiltration

Abstract

Abstract Yeast cell harvesting from cider was performed with a 0.2 μm pore size hydrophilic polyvinylidene fluoride membrane. The microfiltration (MF) membrane exhibited a large flux decline during the first 20 min of operation when challenged with a fermentation broth. This may be attributed to rapid particle polarization initiating membrane fouling. Pore plugging may be more likely to have reduced the flux throughout the experiments than cake formation on top of the membrane, as cross‐flow controls cell build‐up on the membrane and removes some of the cells from the layer. A small proportion of yeast cells were not retained by the membrane; this was attributed to a proportion (1 in 10 000) of the membrane pores being oversize. Aeration during fermentation affected subsequent fouling during MF, probably through alteration of the ability of the microorganism to attach on to the membrane. A high proportion of nonviable cells typical of an aged broth also improved the flux performance, suggesting that any fermentation change having an effect on the yeast cell surface could influence the MF flux.