碩士 / 國立中興大學 / 食品暨應用生物科技學系所 / 97 / Trehalose is a novel multi-functional disaccharide. It serves a variety of functions in organisms and protects organisms to survive harsh environments. In addition, it can be a sweetener, and be a useful compound to preserve biomaterials in the food, cosmetic, and pharmaceutical industries by its ability of stabilizing macromolecules. The most economical pathway for trehalose production is a reversible conversion of maltose into trehalose by trehalose synthase (TSase).
In this study, we developed a new bifunctional gene combined with a recombination gene from a thermophilic Clostridium thermosulfurogenes β-amylase and a thermophilic TSase (PTTS#N503P) which was synthesized using overlap extension PCR and expressed in Escherichia coli system to express the active fusion enzymes. Our aims were focused on the directly converted of starch into trehalose in one-step by the recombinant fusion enzyme (PTTS#N503P–CTBA).
Since the reaction temperature was increased to 60 °C, the novel PTTS#N503P–CTBA fusion enzymes represented 2-fold higher catalytic efficiency than that of PTTS#N503P enzymes. Also, the optimal reaction temperature of recombinant fusion enzyme was changed. The combination of TSase (PTTS#N503P) and thermophilic β-amylase resulted in a broad pH range of 5.0-7.0 with high enzyme activity. For enzyme thermodynamics result, the PTTS#N503P–CTBA represented slightly higher half-life time than that obtained by PTTS#N503P at 60 °C. For the effect of various metal ions, higher concentration (10 mM) of Cesiurn and Magnesiurn could help to stabilize the enzyme with higher catalytic activity. Overally, our novel fusion enzyme (PTTS#N503P–CTBA) is more thermostable and acid-resistant than the wild type. Since it can be used as a functional biocatalyst to directly convert maltose into high value-added of trehalose in one-step accompany with lower cost, we believe it will be another highly potential and useful choice for further industrial applications.
| Identifer | oai:union.ndltd.org:TW/097NCHU5255035 |
| Date | January 2009 |
| Creators | Yi-Lin Sun, 孫薏琳 |
| Contributors | Jei-Fu Shaw, 蕭介夫 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 57 |
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