Medium optimization for lovastatin production by Aspergillus terreus in submerged cultures

An effective experimental design was used to determine the optimal ingredients and compositions in submerged cultures of Aspergillus terreus for lovastatin production. Through medium optimization, lovastatin production of a 7-day fermentation process was maximized at (g/l): glucose (20.0), lactose (89.5), glycerol (30.2), peptone (6.0), soybean meal (4.2), and corn steep liquor (10.0), respectively. This optimized medium resulted in a 4.18-fold increase in lovastatin titres (i.e., 1.05 g/l), as compared with that using basal medium. The lovastatin-producing phase was further increased if adding 0.1 g/l D,L-methionine at 72 hr, which enhanced lovastatin production by 14-17%. However, no benefit was provided to stimulate lovastatin production in the strain when this dosage was added in medium initially or during late idiophase. An adverse effect was also found when the L-methionine was applied.