Production of N-carbamoyl-D-HPG with Recombinant Escherichia coli
碩士 === 國立中興大學 === 化學工程學系 === 87 === Recombinant Escherichia coli cells expressing D-hydantoinase were used as the biocatalysts for the production of N-carbamoyl-D-hydroxyphenylglycine from DL-p-hydroxyphenylhydantoin. The optimal D-hydantoinase activity was observed at 40℃and pH 8.5. Ther...
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| Format: | Others |
| Language: | zh-TW |
| Online Access: | http://ndltd.ncl.edu.tw/handle/j3dda7 |
| Summary: | 碩士 === 國立中興大學 === 化學工程學系 === 87 === Recombinant Escherichia coli cells expressing D-hydantoinase were used as the biocatalysts for the production of N-carbamoyl-D-hydroxyphenylglycine from DL-p-hydroxyphenylhydantoin. The optimal D-hydantoinase activity was observed at 40℃and pH 8.5. Thermostability and reusability of D-hydantoinase were significantly increased upon immobilization. However, the rate of N-carbamoyl-D-HPG production is relatively low, due to low substrate solubility and high substrate mass transfer resistance. In this study we have confirmed that the use of cosolvents such as DMSO can significantly enhance the rate of D-amino acid precursor production with whole cell D-hydantoinase. It was also demonstrated that the use of permeabilized cells as biocatalysts can enhance production rate by reducing mass transfer resistance and can improve product purity by eliminating the secretion of metabolites. The permeabilization of cells also lead to reduced enzyme stability toward organic and thermal denaturation and shift in optimal pH toward lower pH.
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