Filtration of baker’s yeast in an isotonic solution through a 0.45 micron membrane
was investigated for yeast concentrations in the range 0.14 – 51 g/L at filtration pressures
between 40 and 80 kPa. Yeast filtration through membranes depends on applied filtration
pressure and on slurry concentration. It was found that for a yeast volume fraction in
suspension above 0.06 the porosity of the yeast cake becomes weakly dependent on the
suspension concentration. For highly diluted suspension the specific cake resistance
approaches to the minimum value, which is sensitive to the filtration pressure. Correlation
functions of the cake porosity and specific cake resistance were obtained in the investigated
concentration range. It was found that the Kozeny-Carman coefficient is increased with
increasing applied pressure. Both filtration pressure and slurry concentration can be subject
of process control. In the range of moderate yeast concentration, manipulation of filtration
pressure and of slurry concentration might increase the filtrate flux. Obtained results and
assumptions made indicate that complex behavior of yeast cake at high slurry concentration
can be further described within the framework of conventional model by increasing
complexity of subsystems due to aggregation effect.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência, Tecnologia, Inovação” (POCTI) - POCTI/EQU/37500/2001
