Bioproeess Optimization Of2-keto-gluconic Acid Production By Klebsiella Pneumonia

This paper studies a method using two-stage fermentation of Klebsiella pneumoniaeto produce2-keto-gluconic acid.Including: the first stage mainly for Klebsiellapneumoniae bacteria generation, and the second stage for biosynthesis of2-keto-gluconicacid. And do research for the optimization of fermentation conditions, glucoseconcentration, fed-batch fermentation feeding strategie, fermentation medium as well asstrategies to reduce the cost of fermentation in Klebsiella pneumoniae fed-batch2KGAfermentation process. Eventually hope to form an efficient production process which iseasy for industrialization. Specific findings are as follows:Cell concentration, fermentation temperature, pH and aerobic fermentationconditions are basic conditions,establishing the first stage of fermentation conditions ofpH=7.0, temperature=37℃, ventilation=4vvm, dissolved oxygen concentration=20%,when cell concentration reach8, stop adding base, pH dropped to5.5by productionacid, ceteris paribus, this condition is best for2-keto-gluconic acid fermentation. Promote2-keto-gluconic acid generation by adding Ca2+into the fermentation medium.By comprehensive study of fermentation period, conversion rate and intensity ofproduction during2KGA batch fermentation of different initial sugar concentrations.Determine that the initial concentration2KGA batch fermentation of sugar should be100g/L,2KGA feeding fed-batch fermentation process time should be controled to be9h offermentation, batch feeding when the concentration of residual sugar dropped to15~25g/L.2-keto-gluconic acid production reached the maximum157.788g/L at26h offermentation, the largest produing intensity is6.07g/(L).Comparing to NaOH, using ammonia as pH adjusting agents make it easier toobtain the maximum cell concentration, the glucose consumption rate, and2-keto-D-gluconic acid production.Determin a simplified fermentation medium: glucose100g/L, corn steep powder6g/L, KCl0.4g/L, CaCl25g/L, MgSO40.1g/L, which saves costs without affacting thefer-mentation results.