| D-ribose, which is an important constituent of DNA, some coenzymes and vitamins, has extensive usages in foodstuff and medicine field, and it is used in the filed of medicine , deli, study on life sciences and so on. Recently, because of its lower cost and higher yield, production of D-ribose by fermentation has caught more and more inland and oversea investigator's eyes. In this paper, according to the properties of D-ribose, the improved method of measurement of D-ribose concentration in broth by spectrophotometry was constructed, the cell strain of fermentation was screened, the media was optimized by adding different substance, and at last unstructured batch kinetic models was implied in a 2L stirred fermentor.1. Improved method of measurement of d-ribose concentration. In this system the phloroglucinol was used in stead of orcinol. The improved method of measurement of d-ribose concentration in microbial fermented broth by spectrophotometry was established. The optimum measured wavelength is 550 nm, the heating time 25 min and the hydrogen ion concentration 5.5 mol/L. Effect caused by the non-glucose element in the fermentation broth can be ignored and glucose significantly influences the measurement of D-ribose. The effect of glucose concentration on A was obtained through experiments.2. Breeding high D-ribose producing strain by chemical mutation. As an original strain a transketolase-difficient Bacillus subtilis was mutated by diethylsulfate, which was used as a mutation regent. The lethal rate curve of DES was obtained and the best induced mutation conditions were found: DES dosage 0.8%, induced mutation time 15min. Under optimization conditions a large quantity of mutant were selected and a high D-ribose producing strain wasobtained, the output of D-ribose of which was 81.69 percent higher than that of the original strain. The strain yield arrived at 5.1g/100rnL, which has great practical appeal and application potential.3. Effect of D-ribose production by the technology of release. There are great different between inner cell and outer during the course of fermentation. In order to regulate the cellular permeability adding vary dosage of Mn2+ and penicillin to the media, the results was reach that the ultimate D-ribose concentration was increased by 10.27 % and 11.96 % by adding0.03g/100mL Mn2+ and 3 u g/L penicillin.4. Effects of different Components on D-ribose Fermentation. Different influence were got by adding different substance to culture medium. Based on the biosynthesis way of D-ribose and the metabolism regulation theory, various materials were added into the D-ribose fermentation medium and effects of adding materials on D-ribose fermentation were studied.(1) Effect of adding metal ions to media on D-ribose production were studied, and the result showed that ultimate D-ribose concentration was increased by 14.79% by adding 2g/100mLMgSO4.(2) NaF is the inhibitor of the metabolic regulation route-EMP. NaF inhabit the oxygenation of GA-3-P, which inhabit the growth of bacillus. At the same time GA-3-P which is abundant strength the HMP route, promote the production of D-ribose. The ultimate D-ribose concentration was increased by 10.7% by adding 8mg/LNaF.(3) Phosphate are the composition of lots of coenzyme ,and they are important to bacillus growth. By adding 0.1 g/L KH2PO4 and 0.2g/L K2HPO4 to the culture medium the D-ribose concentration was increased by 13.37%.(4) By partially substituting D-glucose with D-gluconic acid indifferent rates, the production of D-ribose increased respectively. Adding gluconic acid at different time during fermentation resolve the problem that plenty of residual glucose was remain at the end of fermentation. In the paper, by adding 5g/100mL gluconic acid into broth after 24h fermentation D-ribose concentration was increased by 18.2%.(5) D-ribose culture medium including adding materials was optimized by orthogonal designing experiments. Using the optimized medium D-r...
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