| Summary: | 碩士 === 義守大學 === 生物技術與化學工程研究所碩士班 === 94 === Hyaluronic acid (HA) is one kind of natural polymer with effective bioactivity on water-holding, joint lubrication and wound repair. It is wildly used in medical materials and cosmetic surgery. Traditionally, most HA has been produced by extraction of cock''s combs, although in recent years, attention has turned to Streptococcus fermentation due to the complexity of animal tissue sources and the consideration of production costs.
Purpose of this study is to design the appropriate media for Streptococcus fermentation. Fermentation media including carbon source, nitrogen source and ions are taken into consideration. In the control experiment, glucose of 10 g/L, yeast extract of 10 g/L and tryptone of 10 g/L were used. The concentration of cell mass reached 1.1 g/L and the yield of HA was 0.3 g/L. For the environments of pH control and better mass transfer, the fermenter was used as the experimental system to check the performance of media design instead of the flask. Among four different carbon sources, sucrose is the best carbon source for HA production. Yield of HA can reach 0.76 g/L by using sucrose of 10 g/L and yeast extract under the agitation speed of 500 rpm in the 5L fermenter. Different nitrogen media were tested for the fermentation system. Only organic nitrogen source is useful for the microbial HA production.
Central composite design with response surface methodology was applied to decide the optimal compositions and concentrations of media in the fermentation system. We find that sucrose of 40 g/L and yeast extract of 12.5 g/L would be the suitable C/N concentrations for the Streptococcus zooepidemicus fermentation. Production cost of HA by using sucrose as carbon medium is NT$0.41/g HA. Results of the investigation can be referred to the production plants in Taiwan.
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