(The) production of fructose from jerusalem artichoke by enzymatic hydrolysis

Abstract

Extracellular inulase which hydrolyze β-2:1`` linked fructose polymer, inulin, was prepared from $\mbox{\underline{Saccharomyces}}$ $\mbox{\underline{fragilis}}$ in the artichoke extract media. The enzyme was purified by sepharose 6B gel filtration and DEAE-Sephadex A-50 ion exchange chromatography. The purified enzyme which was confirmed by electrophoresis running at $p^H$ 9.0 and 6.8 was characterized and used for the production of fructose from Jerusalem artichoke ($\mbox{\underline{Helianthns}}$ $\mbox{\underline{tuberosus}}$ $\mbox{\underline{L}}$.) by enzymatic hydrolysis. The enzyme was found although the general properties of the enzyme varied against substrates in terms of $p^H$ and temperature. Oprimal $p^H$ of invertase and inulase activities were 3.0 and 5.2 respectively, while both activities were stable between $p^H$ 5.0 and 7.0 at 30℃. Optimal temperatures of invertase and inulase activities were shown to be 60℃ and 55℃ respectively. At 50℃ both activities were stable about 4 hrs. With the recovery of 95% of original activities. Inulase activity was more stable than invertase activity at 55℃ and 60℃. At 65℃ both activities were almost lost in 15min. The activation energies for hydrolyses of sucrose and inulin were calculated to be 6.9 Kcal/mole/deg. and 8.0 Kcal/mole/deg. respectively. Km of sucrose and inulin hydrolyses was 6.7mM and 8.0mM. The ratio of Vmax of sucrose hydrolysis to that of inulin hydrolysis was 2.3. The mode of hydrolytic action on inulin by inulase showed to be single chain mechanism. By enzymatic hydrolysis of Jerusalem Artichoke ($\mbox{\underline{Helithus}}$ $\mbox{\underline{tuberosus}}$ $\mbox{\underline{L}}$.) tuber extract which contained inulin type fructose polymers, high fructose sugar mixture which contained 28.8g of fructose and 8.7g of glucose was obtained. The separation of fructose was carried out by Dowex 1-X8 ion-exchange chromatography. After separation 24.5g of pure fructose was obtained from 100g of dried a...