Screening Of Sodium Gluconate High Producing Strain And Studies On Its Fermentation Kinetics

According to the theory of metabolic control fermentation and organic acid fermentation technology,the dissertation focuses on the breeding of sodium gluconate high-yielding strain and its fermentation conditions and kinetics.The main research contents and results are as follows:⑴Sodium gluconate concentration in fermented broth was qualitatively determined with method of paper chromatography and quantitatively analysed with method of spectrophotometry. The qualitative and quantitative determination condition and research method were decided.⑵Ten potential industrial valuable strains,owning characteristics of Aspergillus niger,were screened from the starting orchard soil samples by plate screening of high glucose-resistant,isolation of single colony and second - screening of shaking culture.In the medium without the optimum conditions,the average yield quality of sodium gluconate reached 98.96%,conversion rate of amount-of-substance of gluconic acid to glucose reached 81.66% and the production strength reached 3.69% g·L-1·h-1.⑶The seed medium and fermentation medium were optimized by orthogonal test and the seed culture conditions were optimized by single factor experiments.Thus the optimal seed culture medium,the optimal fermentation medium and the optimal seed culture conditions were determined.⑷The strain of QY-69 was determined for the optimal yield strain by shake flask culture.⑸The fermentation conditions were optimized by single-factor experiments of conditions of 5L fermentor and the optimal culture conditions of fermentation was determined.⑹Three fermentation kinetics models were gotten by the application of MATLAB software.These models can better reflect the batch fermentation conditions of QY-69 in the 5L fermentor.⑺The batch fermentation process of sodium gluconate in the 5L fermentor was tested under the optimal culture condition.By calculated ,the yield of sodium gluconate reached 115.32%,conversion rate of amount-of-substance of gluconic acid to glucose reached 95.15% and the production strength reached 12.22 g·L^-1·h^-1.The innovation of this dissertation in the research field of sodium gluconate fermentation is that MATLAB software is successfully applied to complete data fitting for the batch fermentation process of sodium gluconate.The kinetic models have been constructed which could reflect the regularity of growth,product formation and substrate consumption. These models can better reflect the batch fermentation process of sodium gluconate in the 5L fermentor.These results could provide a theoretical basis for the industrial production of sodium gluconate and have strong guidance.