The optimum conditions for lipopeptide production observed from shaking flask experiments were applied, which included 80 g/L of immobilized cells and 1.25% (v/v) of palm oil. However,the amount of waste glycerol was increased from 2% to 10% (v/v)due to the higher number of the immobilized bacteria obtained from the new immobilization methods. To determine the effective-ness and stability of immobilized cells, productive medium waschanged for every production cycle while the immobilized cellswere maintained in the fermenter. Results demonstrate that bothwaste glycerol and palm oil were reduced at the beginning of eachcycle due to the absorption of substrate by chitosan (Fig. 5a). How-ever, the sorbed oil could enhance its bioavailability to the attachedBacillus sp. GY19 and thereby increase lipopeptide production. Thefirst cycle was examined longer than other cycles in order to esti-mate the shortest production time. Lipopeptide yield increasedsteadily until the fourth day of production. The concentration oflipopeptide decreased afterwards probably due to the consump-tion of lipopeptide by the bacterium under starvation conditions.Thus, the following cycles were operated for 4 days in order to avoidlipopeptide consumption.