Fermentation of the recombinant L. lactis MG1363 was performed in a 5 L jar fermentor (Biotron, Inc., Seoul, Korea), with a working volume of 2 L. Two liters of sterilized fermentation medium (GM17 or MRS medium) was added to the fermentor, and 100 mL of seed culture was inoculated. GM17 medium contained 5 g/L of glucose; however, the glucose concentration was varied from 5 to 50 g/L for the experiments on the effect of glucose on the production of SIase. Erythromycin was added into GM17 media at the concentration of 5 lg/mL. A low speed of agitation (100 rpm) was applied to mix the pH-control reagent (2 N KOH). The fermentation temperature was adjusted to 30 C, and the pH was adjusted to 6.0 with 2 N KOH. The agitation and aeration rates were 200 rpm and 1.0 vvm, respectively.