Fermentation Process Optimization And Kinetic Studies Of Rhamnolipid Production By The Pseudomonas Aeruginosa M14808, Mutated By Simulated Space Environment

The best mutant of P. aeruginosa M14808, mutated by simulated space environment, carried out process optimization of shake-flask immersion fermentation. By the optimal conditions of shake-flask batch fermentation, do the batch fermentation experiments of 3.7L tank, to set up the kinetic models. Use the purified rhamnolipid to do inhibition experiments for H460 and MCF-7.First, use the P. aeruginosa M14808 to do shake-flask liquid fermentation. By the single factor experiments, we know that the best carbon is sunflower oil, the best nitrogen is NaNO3, the best carbon and nitrogen mass ratio is 6:1, initial pH value of 5.0 to 7.0, the fermentation temperature of 34～38℃, the fermentation time of 12-16d. Use the initial pH value, fermentation time, fermentation temperature of three factors as independent variables, rhamnolipid production for response value. Use the central composite response surface method to optimize the fermentation process. By the second-order function of type, response surface graph and chart, when the initial pH value of 6.33, the fermentation time of 14.14d, the fermentation temperature of 36.20癈, the maximum rhamnolipid production reached 21.78g·L-1.Then, do the batch fermentation experiments in the fermentation tank of 3.7L. By measuring the wet weight of cell, rhamnolipid concentration and residual carbon, do the P. aeruginosa M14808 batch fermentation kinetics of the preliminary study. By fitting software, set up the cell growth, product formation and substrate consumption kinetic models. It is found that neutral to slightly acidic environment is suitable for P. aeruginosa M14808 growth and rhamnolipid production. Rhamnolipid production reached 15.684g·L-1 in 30h, the dynamic simulation models can better reflect the strains of batch fermentation process.Use the purified rhamnolipid to do anti-tumor activity by MTT test. Rhamnolipid has a certain extent on the H460 and MCF-7, as rhamnolipid concentration increased, the inhibition increased, it has a better inhibitory effect on MCF-7.