The purpose of the study was to evaluate the effectiveness of continuous biosynthesis of amylases by Bacillus polymyxa B-20 cells, free and immobilized in alginate and chitosane gel. The activity of amylases obtained under chemostat conditions was found between 92 - 118 U/mL, but this highly effective biosynthesis was a short-lived process. Continuous amylase synthesis in a packed-bed reactor (carried out for 144 h) by the bacteria immobilized in calcium alginate resulted in slow reduction of cell productivity of amylases ranging from 69.5 to 44.7 U/g of biocatalyst. Amylase biosynthesis in this process was to a large extent dependent on the dilution rate (D). The highest effectiveness of bacteria production (Y _p/x = 36.1 U/g beads) was obtained at D = 0.8 h^-1, while the highest volumetric productivity Qp = 98 kU/Lh was observed at D = 6.4 h^-1. The bacteria cells immobilized in chitosane gel beads exhibited high yield (70 - 73 U/g beads) for 96 h of incubation, which was followed by a rapid decrease.