Effect of in-use cleaning methods on preventing permeate flux decline in cross-flow microfiltration

With reference io a model baker's yeast slurry, the average permeation flux of a cross-flow microfiltration (CFMF) module containing 20 polysulfone flat membranes with 200,000 molecular cutoff was preliminarily maximised with respect to two cleaning operation modes. Periodic membrane backflushing for as short as 30 s per unit filtration cycle of 5 min (rather than retentate recycling) appeared to be the best and simplest procedure capable of maintaining the overall time-averaged membrane permeability [N-p=11+/-3 g/(s . bar . m(2))] as high as (76+/-20)% of that observed with demineralised water, thus making CFMF of paramount value in cell recycling in secondary metabolite production.