| 1. |
- Katapodis, Petros, et al.
(författare)
-
Production of β-Fructofuranosidase from Sporotrichum thermophile and Its Application in the Synthesis of Fructooligosaccharides
- 2003
-
Ingår i: Food biotechnology. - 0890-5436 .- 1532-4249. ; 17:1, s. 1-14
-
Tidskriftsartikel (refereegranskat)abstract
- Production of β-fructofuranosidase from the thermophilic fungus Sporotrichum thermophile was studied. The effect of nitrogen source, as well as the type and concentration of carbon source on enzyme production was examined. The results from flask experiments were used for the production of the enzyme in 7-l bioreactors. β-Fructofuranosidase from Sporotrichum thermophile showed both transfructosylating and hydrolytic activities. It was optimally active at 60°C, while the optimal pHs for hydrolysis and transfructosylation were 4.0 and 6.0, respectively. Synthesis of fructooligosaccharides was maximized at 20% (w/v) initial sucrose concentration. The major sugar produced by the transfructosylating activity of the enzyme was 6-kestose
|
|
| 2. |
- Mamma, Diomi, et al.
(författare)
-
Biochemical characterization of the multi-enzyme system produced by Penicillium decumbens grown on rutin
- 2004
-
Ingår i: Food biotechnology. - 0890-5436 .- 1532-4249. ; 18:1, s. 1-18
-
Tidskriftsartikel (refereegranskat)abstract
- Penicillium decumbens produced a set of enzymes, including a monoxygenase and two glycosidases, which degrade rutin, a nontoxic flavonoid glycoside, to water-soluble products. The monoxygenase (quercetinase) cleaves the heterocyclic ring in quercetin, the aglycone part of rutin. The glycosidases (alpha-L-rhamnosidase and beta-glucosidase) hydrolyze the bonds between quercetin and rutinose, and between glucose and rhamnose, the constituent monosaccharides of rutinose. Simultaneous production of the three enzymes was optimized following the examination of a number of culture conditions. Maximum enzyme activities were observed when the fungus was grown at 30 °C with an initial pH of 7.0, using 8.0 g/L rutin and 9.0 g/L di-ammonium hydrogen phosphate as carbon and nitrogen sources, respectively. The enzymes were purified to electrophoretic homogeneity by a series of consecutive chromatographic steps including anion and cation exchange as well as gel filtration. The purified quercetinase revealed an apparent tetrameric structure, with a reduced molecular mass of 45 kDa. alpha-L-Rhamnosidase showed an apparent molecular mass of 58 kDa and the purified beta-glucosidase was a tetramer exhibiting a reduced molecular mass of 120 kDa.
|
|
| 3. |
- Hansson, Therese, et al.
(författare)
-
Optimization of galactooligosaccharide production from lactose using β-glycosidases from hyperthermophiles
- 2001
-
Ingår i: Food Biotechnology. - 0890-5436. ; 15:2, s. 79-97
-
Tidskriftsartikel (refereegranskat)abstract
- The maximal production of galactooligosaccharides (GOS) from lactose by (β-glycosidases from the hyperthermophilic archaea, Sulfolobus solfataricus (LacS) (derived from lacS gene) and Pyrococcus furiosus (CelB) (derived from celB gene) was optimized. The performance of these enzymes under extreme reaction conditions, temperatures up to 95°C and lactose concentrations up to 90% (w/v), were studied. The highly thermostable enzymes were shown to be very well suited for oligosaccharide synthesis. For both LacS and CelB the maximum yield of GOS increased with increasing lactose concentration, up to 70% (w/v). The maximum yield of GOS also increased with increasing temperature, and the optimal pH for synthesis was different at different temperatures. The sum of tri- and tetrasaccharides yielded 37% (w/w) in an optimally designed reaction for LacS, and a maximum yield of 40% (w/w) was attained for CelB. Compared to aqueous solution, an increase of the tetrasaccharide/trisaccharide ratio was obtained in two-phase systems with heptane and nonane. These two enzymes from hyperthermophilic organisms were shown to give higher GOS yields at high substrate concentrations than a β-galactosidase from a thermophilic/mesophilic organism (Aspergillus oryzae).
|
|
