supplemented in a shaking incubatorat 37◦C and 200 rpm. Cell growth was monitored by measuringthe optical density at 600 nm (OD600) using a spectrophotome-ter (DU®650; Beckman, Fullerton, CA). The microorganismswere cultured with MB (0.04 mg/mL) and OSP adsorbed withMB (OSP–MB, 20 mg/mL) in which the adsorption MB concen-tration corresponded to 0.04/mL, respectively. Subsequently,the cell growth every hour was determined by UV–vis spec-trophotometry