PROTEASE PRODUCTIVITY IN CHEMOSTAT FERMENTATIONS WITH RETENTION OF BIOMASS ON SUSPENDED PARTICLES

Retention of bacterial biomass (Bacillus firmus) in a chemostat by a new carrier material, Luxopor, led to increased productivity of protease. Luxopor is a porous mineral product of irregular shape. When these particles are put into a fermenter, aeration and stirring make them float. Fermenters with Luxopor loadings of 200 and 500 g l** minus **1 were run as chemostats parallel to a control chemostat without it. The Luxopor particles contained greater than 50% of the biomass in the chemostats (50 mg dry cell weight g** minus **1), which had a higher biomass and protease activity in the culture fluid than the control chemostat. The overall protease productivity was up to four times higher than that of the control.