when the bacterial cells cultivated in a 100 mL erlenmeyer flask containing 20 mL medium reached 1.0 in terms of optical density at 660 nm (OD660)at 15องศา on a 200 rpm shaker, 2 ml of the culture was transferred as the inoculum into a 500mL erlenmeryer flask containing 100 mL of the fresh medium to examine the cell growth and pigment production.