碩士 / 國立中興大學 / 食品暨應用生物科技學系 / 97 / In this study, we plan to produce high value trehalose from rich starch by enzymatic method. Rice powder was used as the starch source and hydrolyzed with several relative enzymes: α-amylase, β-amylase, and pullulanase to obtain rice saccharificate consisting of maltose as main component. Finally, the conversion of maltose to trehalose was catalyzed by thermostable Picrophilus
torridus trehalose synthase(PTTS ).
The complex saccarificate solution which inverts by recombinant PTTS was further refined with separation and purification. The solution was re-saccharified by glucoamylase to hydrolyze other disaccharides and trisaccharides into glucose. Saccharified solution was then fermented with Saccharomyces cerevisiae, and converted glucose to ethanol and CO2. The reaction mixture was filtered with kieselguhr and charcoal activated and demineralized and decolored by ion-exchange resin of a strongly acidic cation exchange resin DIAION PK 216 and weakly basic anion exchange resin DIAION WA30LL.
For the enzyme extraction and purification, the results showed: (1) The activity of β-amylase from sweet potato (Tai-Lon NO. 10) was 239.1 U/mL (65.95 U/g sweet potato), and the molecular weight was estimated to be 53.17 kDa by SDS-PAGE analysis. Other residual byproduct, such as the starch recovery yield from sweet potato was 11.17%; the total dietary fiber from sweet potato residual was 14.08%. (2) The molecular weight of trehalose synthase from Picrophilus torridus trehalose synthase in Rosetta-gami B(DE3) was estimated to be 66.28 kDa, it was extracted by sonication and partially purified by a two-step purification strategies of ultra-filtration and subsequent precipitation with solid ammonium sulphate. The purification fold was 4 fold and the enzyme yield was 10.3%. The trehalose conversion rate can be reached
56.32 ± 0.99％ at 50 ℃.
The dry-milled japonica rice from Taiwan was liquefied and saccharified at 50℃, pH 5.0, 21~22 hr to obtain highest amount of maltose (the maltose conversion rate can reach to 82.40 ± 2.84%) and lowest amount of glucose and maltotriose. The non-soluble solid content was about 7% (the total dietary fiber content was 61.82%). The conversion of maltose to trehalose catalyzed by trehalose synthase at 50℃, pH 5.0, 20~24 hr resulted in a 50% of conversion rate. After re-saccharification process, the solution was then fermented by S. cerevisiae for 72 hrs. All residual sugar, except trehalose, will be fully hydrolyzed into glucose and separated by two-step procedure. The final crystal product with high purity trehalose was identified by HPLC. The crystallization recovery yield and purity has been established as 92.5 ± 8.66% and 92.3%, respectively.
| Identifer | oai:union.ndltd.org:TW/097NCHU5255067 |
| Creators | Wei-Hsin Chang, 張巍馨 |
| Contributors | Chin-Shuh Chen, 陳錦樹 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 91 |
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