Results demonstrate that both waste 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.