Studies On The Up-stream Technology Of 5'-Ribonucleotides Produced By Enzymolysis Method

5'-Ribonucleotides is high added value products used in food industries or having important applications in the pharmaceutical industry. Till now, enzymatic method is still the only method that can be utilized for industrial production of all four types of 5'-ribonucleotides (5'-CMP, 5'-GMP, 5'-UMP and 5'-AMP). And Japanese have succeeded in large-scale production of nucleotides when they grasped this method as early as 1970s. However, there are few factories that have the capacity of producing all four 5'-ribonucleotides. The capital difficulty is the kernel technique of enzymatic hydrolysis process. Thus the products of them can hardly be competed with others especially Japanese companies. In order to change this disadvantageous status, we have developed this item studying on the production of 5'-ribonucleotides by enzymatic hydrolysis method. And it is processed smoothly now, studies of the laboratory-level production have been finished, four types of highly purified nucleotides have been gained from this step. And the expand-level study would be processed on the basis of laboratory-level study recently. The central content of this paper is focused on the up-stream technology of 5'-ribonucleotides produced by enzymatic method. And it include two parts, one is the production of nuclease P₁ fermented by Penicillium citrinum M02, and the other is the production of 5'-ribonucleotides. As compared to overseas companies, the mainly gaps currently of these two parts are lower P₁ production and lower yield rate of 5'-ribonucleotides. These gaps not only lead to higher cost of the whole technology, but also bring great difficulties on the next downstream technologies such as separation and crystallization and so on. Therefore both technological optimization and theories study have been processed in this paper in order to furthest improve productions of nuclease P₁ and 5'-ribonucleotides. And thus it can successfully carried out with the whole item on the basis of this paper. In the aspect of nuclease P₁ fermentation, seeds cultivation, shaking flask and airlift tower loop reactor fermentation have been firstly studied. In addition, the primary fermentation kinetics of batch fermentation in ALR has also been simply studied. It can be found that Logistic model can perfectly characterize the process of thalli growth, and Luedeking-Piret equation for enzyme production can perfectly describe the fermentation of Nuclease P₁ when it has not get to the peak of the production. And one conclusion can also be gained from this study that enzyme production is partly combined to the growth. Secondly, parts of fermentation conditions, such as seeds age, seeds inoculated rate, initial pH, temperature and so on, have been studied in this paper. In addition, the effects of several compounds on nuclease P₁ production, such as zinc sulfate, surfactants phytic acid compounds, nucleic acid compounds and so on have also been simply studied. Finally, statistical experimental methods have been employed to optimize the medium of Nuclease P₁ in this paper. The results of two experiments show that corn steep liquor could obviously advance the production. In addition, one model, which can characterize the fermentation perfectly, was gained from these experiments. When nuclease P₁ was produced on the optimized medium calculated from this model, the yield of it is 648.3u/ml that compared with 661u/mL calculated. And it improved 70 percent compared with the 380u/mL, which was gained on the original medium at the same time.In the aspect of enzymatic hydrolysis of yeast RNA of this paper, time course of 5'-Ribonucleotides' production and primary kinetics of this enzymatic reaction have been firstly studied. From these experiments, we can found that it is strongly inhibited by substrate yeast RNA. And the concentration should be controlled if highest yield of enzymatic hydrolysis reaction want to be gained. Secondly, the modulation effect of zinc ion to the enzymatic hydrolysis reaction has been simply studied. It can be found fro...