The Studies On L-Tryptophan Fermentation Conditon And Alalsis Of Fermentation Kinetics

According to the theory of metabolic control fermentation, the dissertation focuses on fermentation condition and fermentation kinetics of L-tryptophan producing strain. The main research contents and results are as follows:[1] The genetic markers of TQ2223,one L-Trp producing strain,were tested,and its production was also tested. Under the fermentation condition without being optimized, It could produe L-trptophan 6.86g/L.[2]the batch fermentation condition of strain TQ2223 in shake flask was studied. The seed medium and fermentation medium were optimized and the seed culture conditions were also studied. Under the optimum condition, strain TQ2223 could produce L-tryptophan 8.65g/L after fermentation for 72 hours by flask-shaking batch fermentation.[3] Based on the above optimum condition, the batch fermentation was performed with strain TQ2223 in 5L-liter fermentor. The L-Trp batch fermentation kinetics was studied by neural network based on the experimental data from 5-liter fermentor's batch fermentation. Three kinetic models were constructed which could reflect the regularity of growth, product formation and substrate consumption in the process of batch fermentation.[4] Fed batch fermentation was studied with strain TQ2223 according to the optimum condition of batch fermentation. The optimum initial glucose concentration was 80g/l in shake flask fed batch fermentation. The intermittent glucose feeding was performed at the 24th, 30th, 36th, 42th, 48th, 54th ,60th,66th hour respectively. The production of L-tryptophan could reach 10.4g/L after fermentation for 72 hours.And the result of feeding (NH4)2SO4 ,L-Phe and L-Tyr are also study in both shake flask and 5L fermentor. .At the best feeding modle ,it could produce L-tryptophan 13.4g/L after fermentation for 72 hours.