Research On Metabolic Regulation Of ?-carotene Production By Fermentation Of Blakeslea Trispora

By virtue of its great antioxidant activity, ?-carotene has broad application prospects. Currently, mixed fermentation of Blakeslea trispora(B. trispora)(+) and B. trispora(-) is the most effective way to produce ?-carotene. However, it is unclear that the interaction relationship between B. trispora(+) and B. trispora(-). In this paper, we researched on it. We explored the necessary conditions for the formation of ?-carotene, and studied the relationship between the sexual reproduction of B. trispora and the yield of ?-carotene. On this basis, we further studied the metabolic regulation of ?-carotene biosynthesis, and bringed in BP neural network to optimize the fermentation process. The main results were as follows:(1) The fermentation characteristics of B. trispora(+) and B. trispora(-) was studied in respective culture conditions and mixed culture conditions. And we proved that ?-carotene and trisporic acid would be synthesized in large quantities only under mixed culture conditions.The synthesis of ?-carotene and trisporic acid were synchronized. Besides, we exchanged of the fermentation broth of B. trispora(+) and B. trispora(-), and added ?-ionone to treat the fungus. The results showed the co-culture of B. trispora(+) and B. trispora(-) was necessary for the synthesis of a large mount of ?-carotene. It suggested the direct interaction of B. trispora(+) and B. trispora(-) was conducive to the synthesis of ?-carotene(2) The plate method was used to explore the relationship between the sexual reproduction of B. trispora and the formation of ?-carotene. The results of the study suggested that the sexual reproduction, the synthesis of trispora acid and ?-carotene were positive correlation. Therefore, the production of ?-carotene could be improved by enhancing the effect of sexual reproduction or increasing the amount of trisporic acid yield. In this paper, we applied the method of response surface analysis to optimize the conditions of sodium acetate, 22? low temperature treatment, ?-ionone which had significant influence. And the optimal control conditions were sodium acetate 1.95 mM, 22? low temperature treatment 2.52 h, ?-ionone 141 ?M.(3) The metabolic regulators of ?-carotene biosynthesis was studied systematically. And we found five regulatory factors which strengthened ?-carotene synthesis. They were ketoconazole, BHT, penicillin, geraniol and sodium citrate. We constructed a BP neural network model of ?-carotene formation based on the data of single-factor tests and orthogonal design. Using sequential quadratic programming method to solve the model, the optimal control condition was obtained. It was ketoconazole 83.2 mg/L, BHT 7.8 mM, penicillin 69.5 mg/L, geraniol 45.3 mg/L and sodium citrate 2.31 g/L. Under the new fermentation conditions, ?-carotene yield reached 357±9.4 mg/L, increased by 95.08% compared with the control. This study improved the yield of ?-carotene significantly.