Abstract: This study aimed to improve the yield of α-amylase inhibitor and the efficiency of carbohydrate utilization during the fermentation of Streptomyces coelicoflavus (S. coelicoflavus). The metabolic network leading to the biosynthesis of α-amylase inhibitor was analyzed to find out the key nodes which influenced the production of α-amylase inhibitor. The effects of sodium glutamate on the metabolic flux distributions during the middle and late periods of fermentation were studied, and metabolic flux analysis for α-amylase inhibitor production at pseudo-steady state was also conducted. The results showed that the metabolic flux channeled to the α-amylase inhibitor biosynthesis pathway was 1.84 in batchwise fermentation without the addition of sodium glutamate, while, with the addition of sodium glutamate (the concentration was maintain at 4.0 g/L), the metabolic flux was 3.18, suggesting that the addition of sodium glutamate could change the metabolic flux distributions of the key nodes (glucose-6-phosphate, sedoheptulose-7-phosphate, and glutamate) and enhance the biosynthesis of α-amylase inhibitor.

Key words: α-amylase inhibitor, metabolic flux analysis, sodium glutamate