PROCESS FOR THE PRODUCTION OF ISOMALTOOLIGOSACCHARIDES
The present invention provides a method for the production of oligosaccharides by the fermentation of dextransucrase-producing microorganisms with sucrose and maltose. The disclosed process allows for the control of the final composition of the isomaltooligosaccharides by adjustments to pH and the initial ratio of sucrose to maltose.
1 - 52 .
53 . A method for the preparation of oligosaccharides comprising:
(a) contacting an inoculum of dextransucrase-producing bacterial cells with a culture medium comprising sucrose and maltose to form a fermentation mixture comprising up to 10% of the inoculum and at least a 2:33:1 starting ratio of sucrose to maltose, where the dextransucrase is of enzyme classification (E.C.) 2.4.1.5;
(b) fermenting the bacteria cells in the fermentation mixture while controlling the pH between 4 and 6.0 by adding acid or base to the fermentation mixture; and
(c) removing the bacteria cells from the fermentation mixture to produce a final composition oligosaccharides comprising maltosyl-isomaltooligosaccharides with degrees of polymerization greater than 2 (DP2).
54 . The method of claim 53 , wherein the starting ratio is at least 2.75:1 or at least 7:1.
55 . The method of claim 53 , wherein the ratio of sucrose to maltose is adjusted during the fermentation process by the addition of either sucrose or maltose.
56 . The method of claim 53 , wherein the fermentation mixture has up to 30% total sugar at the start of fermenting under step (b).
57 . The method of claim 53 , wherein the dextransucrase-producing bacterial cells are Leuconostoc mesenteroides, Leuconostoc citreum, Leuconostoc gasicomitatum , or Leuconostoc kimchii.
58 . The method of claim 53 , wherein the dextransucrase-producing bacterial cells are Leuconostoc mesenteroides ATCC 13146 or Leuconostoc mesenteroides NRRL B-742.
59 . The method of claim 53 , wherein the dextransucrase-producing bacterial cells Weissella confusa, Weissella cibaria, Lactococcus spp, Pediococcus spp. Pediococcus pentosaceus, Streptococcus mutans, Streptococcus oralis, Streptococcus sanguinis , or Lactobacillus reuteri.
60 . The method of claim 53 , wherein the base comprises an alkali earth metal hydroxide or carbonate.
61 . The method of claim 53 , wherein the bacteria cells are removed by filtration.
62 . The method of claim 53 , also comprising removing mannitol.
63 . The method of claim 53 , wherein the final composition of the oligosaccharides comprises isomaltooligosaccharides with one or more α-(1→4) at the reducing end and α-(1→6) linkages with a degree of polymerization between 3 and 9 or between 3 and 10.
64 . The method of claim 63 , wherein the final composition of the oligosaccharides comprises isomaltooligosaccharides that further comprise α-(1→4), α-(1→3) and/or α-(1→2) branching.
65 . The method of claim 53 , wherein the final composition of the oligosaccharides are essentially free of ash, mineral acids, residual proteins, sugar alcohols, and organic acids.
65 . The method claim 53 , further comprising providing the oligosaccharides as a concentrated solution.
66 . The method of claim 53 , further comprising providing the oligosaccharides as a powder.
67 . The method of claim 66 , wherein the powder is produced by drying, spray drying or freeze drying.
68 . A composition produced by the method of claim 53 .
69 . A method for the preparation of oligosaccharides comprising: (a) contacting a feedstock comprising a fixed ratio of sucrose to maltose with a dextransucrase-producing microorganism in a culture medium; (b) fermenting the feedstock with the bacteria cells at a pH between 4 and 8; (c) removing the bacteria cells; and (d) polishing; wherein the final oligosaccharides produced are essentially free of ash, mineral acids, residual proteins, sugar alcohols, and organic acids.
70 . The method of claim 69 , also comprising removing mannitol.
71 . A composition produced by the method of claim 69 .