Clarification of yeast by colloidal gas aphrons

Colloidal gas aphrons or CGAs were employed in a flotation column for the recovery of yeast from aqueous solutions. The CGAs sparging rate was a critical factor that governed the efficiency of the process. The separation efficiency was less than 30% at a sparging rate of 1.3 ml sec super(-1) and increased exponentially up to 90% as the sparging rate was increased to 2.4 ml sec super(-1). Whereas there was no appreciable change in the separation efficiency with CGAs sparging rates for high initial feed concentrations, the maximum achievable efficiency decreased with an increase in the initial feed concentration. In general, a decrease in pH will improve the separation efficiency.