| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 93 === The effect of agitation rate on the production of hyaluronic acid (HA) by Streptococcus zooepidemicus ATCC 39920 was investigated in this study. The result first showed that under a specified agitation rate, the production of HA was not influenced by the level of dissolved oxygen (DO) when DO was kept above 25% of saturation. The influence of agitation rate on HA production could be described as follows: (1) The yield of HA increased with agitation rate in the range from 200 to 600 rpm. Since the results showed that both oxygen transfer coefficient and nutrient assimilation rate did not affect the production of HA, the increase in the yield of HA could result from the increase in shear force. (2) The yield of HA decreased when agitation rate increased from 600 to 800 rpm, which might attribute to the inhibition in HA production by extremely high shear force. In addition, the molecular weight of the obtained HA was between 1.21×106 Da and 1.34×106 Da in the range of 200 to 600 rpm. The result indicates that the molecular weight of HA is not significantly affected by agitation rate. Based on the above findings, agitation shear force is thought to be the critical factor for scale up of HA fermentation.
|
|---|
