Fructosyltransferase production by Aspergillus japonicus TU-26 in submerged and solid-state fermentation
| Autor: | Po-Hsin Huang, 黃伯欣 |
|---|---|
| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 The production of fructosyltransferase (FTase) by Aspergillus japonicus TU-26 in submerged and solid-state fermentation was investigated. Submerged fermentation was carried out in a 5-L fermentor at 30 ℃, 1vvm, 500 rpm and pH 6, with a working volume of 2-3 L. The culture medium consisted of 1% yeast extract, 0.5% KH2PO4, 0.05% MgSO4•7H2O and sucrose of varied concentration. A maximum FTase activity of 359 U/mL was obtained at hour 24 when batch fermentation with 200 g/L of sucrose was performed. A maximum enzyme activity of 534 U/mL was achieved at hour 40 when 250 g/L of sucrose was used. As the fermentation was progressed, sucrose was converted to difructoside, fructo-oligosaccharides (FOS, including: trifructoside, tetrafructoside, 1-kestose, nystose and fructosyl nystose), glucose and fructose. Eventually, all of the di- and oligo-saccharides were hydrolyzed into glucose and fructose. During the fermentation, FTase was continuously produced until both sucrose and FOS disappeared. In fed-batch fermentation, continuous sucrose-feeding to reach a final concentration of 200 g/L or 250 g/L in the first 24 hours was carried out. Maximum FTase activities of 463 U/mL and 615 U/mL at hour 36 and 52, respectively, were achieved. In solid-state fermentation, an omission test revealed that wheat bran, rice hull, yeast extract, sucrose, KH2PO4 and MgSO4•7H2O played important roles for the production of FTase by A. japonicus. During the solid-state fermentation, FTase production peaked at day 5. More wheat bran added resulted in more FTase produced. Solid-state fermentation and submerge fermentation were compared in FTase productivity based on that the cost of the solid culture medium in a 500-mL flask was equivalent to 100 mL of submerged culture medium. A flask of solid-state culture produced 42930 U of FTase, whereas 100 mL of submerged culture in the fed-batch fermentation with continuous sucrose-feeding gave 46310 U of FTase. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|