For lipopeptide production in the stirred tank fermenter, the bacterial immobilization process was optimized to enhance bacterial colonization on chitosan. Results showed that the bacterialimmobilization should be carried out in 100% of LB medium at pH6 with repeated immobilization for 3 cycles. This process enhancedthe attachment of bacteria on chitosan flake to about 1 × 1010CFU/gimmobilized cells from the third cycle of immobilization (Fig. 4).Therefore, this new immobilization method was applied in the fer-menter operation.