| Summary: | 碩士 === 義守大學 === 生物技術與化學工程研究所碩士班 === 95 === Hyaluronic acid is one kind of natural linear polymer. The microbial production of hyaluronic acid is a recent development to avoid viral infection and reduce operation costs. The goal of the research is to find the most suitable feeding strategy for streptococcus fermentation.
From the different inoculation time tests, the optimal inoculation for hyaluronic acid is to transfer the inoculums to the main culture at the eighth hour of the preculture. This way, productivity of the hyaluronic acid was 0.057 g/L/hr. This is higher than the other inoculation time conditions.
Carbon sources and their concentrations will stimulate or change the metabolism of the streptococcus. Among the four kinds of carbon sources examined, sucrose was the best carbon source for the highest productivity of hyaluronic acid. Calculation of metabolic fluxes on the carbon atoms discharged from the sucrose medium into the hyaluronic acid or any of several byproducts shows the optimal sucrose concentration should keep at 30 g/L to promote hyaluronic acid productivity.
Eleven concentration combinations of yeast extract and tryptone are tested to prove which induces the most significant change of biomass and hyaluronic acid. The result shows that yeast extract of 10 g/L and tryptone of 10 g/L used in the medium will be most efficient for the production of hyaluronic acid.
The above results include: inoculation after the eighth hour in the preculture. And sucrose of 30 g/L, yeast extract of 10 g/L and tryptone of 10 g/L in the medium are applied to the conditions of the fed-batch culture. The feeding amount of sucrose is calculated by using the specific growth rate and sucrose consumption rate of streptococcus. Due to prolonged the logistic growth of streptococcus effected by using this strategy, the concentration of hyaluronic acid reached at 7.13 g/L.
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