Abstract
In this review the problems and solutions on the membrane separation of microbial cell suspensions in food and biochemical industries were discussed. The deposition of filter cakes on membranes decreases the permeation flux in the filtration. Currently filter aids such as diatomaceous earth are widely used to decrease the permeation resistance of the filter cakes although the cakes containing filter aids are discharged as industrial wastes. Crossflow filtration is a method to obtain high permeation fluxes by suppressing the formation of filter cakes on the membranes. High permeation fluxes could be obtained in the crossflow filtration of suspensions of spherical cells such as baker's yeast. However, the authors showed that the permeation flux decreases in the suspensions of rod-shaped cells or microbial suspensions containing fine particles from culture media and biopolymers. It was shown that the permeation fluxes could be recovered by the use of a modified backflushing method by the authors. The development of biodegradable polyester membranes for dead-end filtration to decrease the industrial waste was also discussed.
