Enhancement Of Glutamate Fermentation Performance By Using An On-line Glucose Concentration Control System

In industrial glutamate fermentation, intermitted feeding glucose with the help of off-line glucose measurement is generally necessary. This kind of feeding strategy could cause large variations in glucose concentration so that it is not favorable for the achievement of efficient and stable glutamamte fermentation. This paper studied the optimal control of glutamate fermentation progress based on self-developed on-line control system of glucose concentration by strain Corynebacterium Glutamicum S9114.Glutamate fermentation is characterized with typical non-growth association behavior, glucose consumption is correlated with ammonia consumption amount, O2 consumption amount and CO2 evolution amount during glutamate production. With the aid of on-line monitoring ammonia consumption, O2 consumption and CO2 evolution amount, glutamate fermentation performance under different operation conditions and pre-determined glucose concentrations was mainly investigated combined with the self-developed new online automatic control system of glucose supplement. When glucose concentration was controlled around a lower level of 5 g/L~10 g/L, the final glutamate concentration could reach a relatively higher level of 80 g/L, increased by 100% and 15% compared to high glucose concentration culture and intermitted feeding culture. And the conversion ratio was increased by 55% and 27%. In this way, the huge osmotic stress change due to the large glucose concentration variation with the intermitted feeding method could be avoided and the enhancement and stability of glutamate fermentation performance could be expected. Relatively stable and lower glucose concentration (5 g/L~10 g/L) is favorable to promote cellular metabolic ctivity (reflected by oxygen uptake rate, OUR) and key enzyme in glutamate fermentation-Glutamate Dehydrogenase activity (GDH), thus glutamate fermentation performance was enhanced.