Optimization Of D-Ribose Production And Studies On Its Fermentation Kinetics

The D-ribose analyzing method of orcinol, the physiological properties and genetic marker of D-ribose producing strain B1916, the optimization of D-ribose fermentation process as well as the kinetics of D-ribose fermentation under 5L fermentation tank were studied in this paper.The optimum conditions were defined in this paper, in which the D-ribose content was detected by orcinol color development method,Characteristics of D-ribose-producing strain B1916 were studied. The results showed that B1916 was a triple deficient mutant of Shi, Ade and His, had lost the ability of spore formation, but could resist high D-ribose concentration to 100g/L. And there was no gluconic acid detected in broth. All these meant that B1916 was a potent D-ribose high production strain.Based on single factor experiments and orthogonal design, the optimum inoculation medium was determined as following (g/L): sorbitol 20, corn steep liquor 25, K2HPO4 3, KH2PO4 1, yeast extract paste 2.5. The optimal culture conditions were 36 C, pH 7.2, 170r/min.The response surface analysis was used on determining the composition of fermentation medium. The result was listed as following (g/L): glucose 175, corn steep liquor 20, (NH4)2SO48.1, MnSO4 0.056, CaCO3 20 (sterilized respectively). And it was found that B1916 had different optimum pH of cell growth and D-ribose formation. So, before the cells reached post-exponential growth, pH value was controlled to 7.2, then varied to 6.7. The studies on D-glucose and D-gluconic acid based media fermentation showed that D-gluconic acid partially overcomes yield limitations encountered with D-glucose, but too high D-gluconic acid concentrations were toxic for the cells.Based on data of dry cell weight, concentration of glucose, D-ribose yield from 5L fermentation tank, feeding by SAS software, the kinetic model of fermentation was established.These models described the strain growth, product accumulation, and substrate consumption well. It would be help to the production of D-ribose byfermentation.