The effect of turbulence promoter on cross-flow microfiltration of yeast suspensions: A response surface methodology approach

This work studies the influence of operating factors on the microfiltration of baker's yeast (Saccharomyces cerevisiae) in presence of static mixer as turbulence promoter. A response surface methodology (RSM) was used to investigate influence of the selected operating conditions as well as their interactions on the process performance. The factors considered for design of experiments were transmembrane pressure, feed flow rate and suspension concentration. Box-Behnken design was selected for experimental work. The responses considered were permeate flux without static mixer; permeate flux with static mixer; permeate flux improvement and reduction of specific energy consumption. The effect of the turbulence promotion on microfiltration performances was investigated by using Kenics static mixer. The results suggested that polynomial model is adequate for representation of selected responses. The most significant factor influencing permeate flux without turbulence promoter was suspension concentration, while when turbulence promoter was used the most significant operating factors were transmembrane pressure and feed flow rate. The flux improvement was in the range between 89.32% and 258.86%, depending of experimental conditions. The best results considering flux improvement as well as reduction of specific energy consumption were obtained for moderate feed flow rates. (C) 2010 Elsevier B.V. All rights reserved.