Resumen
The invention relates to a method of obtaining industrially-viable prebiotic oligosaccharides, using a novel extracellular enzyme (fructofuranosidase) of Xanthophyllomyces dendrorhous, which is characterised in that it also has transfructosilase activity. The invention also relates to a method of obtaining an enzymatic product with fructofuranosidase activity, as well as the substantially-pure enzyme with said activity. The enzymatic product and the enzyme offer the advantage of having a high performance spectrum, high heat stability and a high specific activity Said prebiotic oligosaccharaides are used in food.
Reivindicaciones
1. A process for obtaining an enzymatic product with fructofuranosidase activity, which comprises culturing Xanthophyllomyces dendrorhous (Phaffia rhodozyma) cells in a maltose-based yeast medium at a temperature of 23 deg. C and constant orbital shaking of 160 rpm. 2. A process according to claim 1, which comprises culturing Xanthophyllomyces dendrorhous cells in a yeast minimal or rich medium based on different carbon sources (maltose, derivatives of the disaccharide, succinate) at a temperature comprised between 21 and 25 deg. C and in a range of constant orbital shaking comprised between 100 and 250 rpm. 3. A process according to claims 1 and 2, further comprising the step of recovering the enzymatic product from the culture medium and/or from the cell suspension. 4. A process according to any of claims 1-3, wherein the Xanthophyllomyces dendrorhous cells belong to a strain selected from the group consisting of ATCC: MYA-131, ATCC 24230, ATCC 24202. 5. An enzymatic product with fructofuranosidase activity which can be obtained by the defined process in any of claims 1-4. 6. An enzymatic product according to claim 5, characterized in that the fructofuranosidase activity has low substrate specificity, acting on sucrose, raffinose, 1-kestose, nistose, and palatinose. 7. An enzymatic product according to any of claims 5 and 6, characterized in that it has no fructofuranosidase activity on leucrose, maltose, maltotriose, and maltoheptose. 8. An enzymatic product according to any of claims 5-7, wherein the fructofuranosidase activity shows maximum activity in the pH interval between 5.5 and 7.5 at 42 deg. C, and in a temperature interval of 50 to 75 deg. C. 9. An enzymatic product according to any of claims 5-8, characterized in that it has fructosyltransferase activity in presence of one or several glucidic substrates. 10. An enzymatic product according to claim 9, characterized in that the glucidic products are fructooligosaccharides. 11. An enzymatic product according to claim 10, wherein the products resulting from fructosyltransferase activity are oligosaccharides with -1,2, and -2,6 bonds. 12. An enzymatic product according to claim 11, wherein the products resulting from fructosyltransferase activity are basically neokestose, 1-kestose 13. A process for obtaining oligosaccharides which comprises allowing the enzymatic product defined in any of claims 5-12 to act on one or several glucidic substrates. 14. A process of obtaining a substantially pure enzyme with fructofuranosidase activity from the enzymatic product obtained by the process according to claims 1 and 2, comprising the additional step of purifying the enzymatic product using, among other techniques, tangential flow filtration, molecular filtration and/or ion exchange chromatography, until obtaining the substantially pure enzyme. 15. A process according to claim 14, wherein the Xanthophyllomyces dendrorhous cells belong to a strain selected from the group consisting of ATCC: MYA-131, ATCC 24230, ATCC 24202. 16. A substantially pure enzyme with fructofuranosidase activity which can be obtained by the process defined in any of claims 14 and 15. 17. An enzyme according to claim 16, characterized in that the fructofuranosidase activity has low substrate specificity, acting on sucrose, raffinose, 1-kestose, nistose and palatinose. 18. An enzyme according to any of claims 16 and 17, characterized in that it does not have fructofuranosidase activity on leucrose, maltose, maltotriose, maltoheptose. 19. An enzyme according to any of claims 16-18, wherein the fructofuranosidase activity shows maximum activity in the pH interval between 5.5 and 7.5 at 42 deg. C, and in a temperature interval between 50 and 75 deg. C. 20. An enzyme according to any of claims 16-19, characterized in that it has fructosyltransferase activity in the presence of one or several glucidic substrates. 21. An enzyme according to claim 20, characterized in that the glucidic products are fructooligosaccharides. 22. An enzyme according to claim 21, wherein the products resulting from fructosyltransferase activity are oligosaccharides with -1,2, and -2,6 bonds. 23. An enzyme according to claim 22, wherein the products resulting from fructosyltransferase activity are basically neokestose and 1-kestose. 24. An enzyme according to any of claims 16-23, characterized by having a molecular weight calculated by molecular filtration of approximately 214 kDa in natural conditions, and 170 kDa in denaturing conditions. 25. A process of obtaining oligosaccharides which comprises allowing the enzyme defined in any of claims 16-24 to act on one or several glucidic substrates.
