A process (51) for producing alternan-oligosaccharide (8), comprising contacting in a reactor (11) sucrose (9) with a catalytically effective amount of alternansucrase enzyme (13) and acceptor molecules (12), wherein the alternansucrase enzyme (13) and acceptor molecules (12) are present in the reactor (11) in an aqueous liquid (4) and the sucrose (9) is continuously or half-continuously fed to the reactor (11), and wherein the sucrose (9) and the acceptor molecules (12) are converted to alternan-oligosaccharide (8), and fructose (6) is formed as a by-product, continuously or half-continuously removing at least a part of the fructose (6) from the reactor (11) by membrane filtration (17).

Compositions are disclosed herein comprising dextran that comprises (i) 87-93 wt % glucose linked at positions 1 and 6; (ii) 0.1-1.2 wt % glucose linked at positions 1 and 3; (iii) 0.1-0.7 wt % glucose linked at positions 1 and 4; (iv) 7.7-8.6 wt % glucose linked at positions 1, 3 and 6; and (v) about 0.4-1.7 wt % glucose linked at (a) positions 1, 2 and 6, or (b) positions 1, 4 and 6. Aqueous forms of this composition have enhanced viscosity profiles. Further disclosed are methods of using compositions comprising dextran, such as increasing the viscosity of an aqueous composition. Enzymatic reactions for producing dextran are also disclosed.

Compositions are disclosed herein comprising dextran that comprises (i) 87-93 wt % glucose linked at positions 1 and 6; (ii) 0.1-1.2 wt % glucose linked at positions 1 and 3; (iii) 0.1-0.7 wt % glucose linked at positions 1 and 4; (iv) 7.7-8.6 wt % glucose linked at positions 1, 3 and 6; and (v) about 0.4-1.7 wt % glucose linked at (a) positions 1, 2 and 6, or (b) positions 1, 4 and 6. Aqueous forms of this composition have enhanced viscosity profiles. Further disclosed are methods of using compositions comprising dextran, such as increasing the viscosity of an aqueous composition. Enzymatic reactions for producing dextran are also disclosed.

Reaction compositions are disclosed herein comprising at least water, beta-glucose -1-phosphate (beta-G1P), an acceptor molecule, and an alpha-1,3-glucan phosphorylase enzyme. These reactions can synthesize oligosaccharides and polysaccharides with alpha-1,3 glycosidic linkages. Further disclosed are alpha-1,3-glucan phosphorylase enzymes and methods of use thereof.

Reaction compositions are disclosed herein comprising at least water, beta-glucose -1-phosphate (beta-G1P), an acceptor molecule, and an alpha-1,3-glucan phosphorylase enzyme. These reactions can synthesize oligosaccharides and polysaccharides with alpha-1,3 glycosidic linkages. Further disclosed are alpha-1,3-glucan phosphorylase enzymes and methods of use thereof.

An enzymatically produced soluble α-glucan fiber composition is provided suitable for use as a digestion resistant fiber in food and feed applications. The soluble α-glucan fiber composition can be blended with one or more additional food ingredients to produce fiber-containing compositions. Methods for the production and use of compositions comprising the soluble α-glucan fiber are also provided.

An enzymatically produced soluble α-glucan fiber composition is provided suitable for use as a digestion resistant fiber in food and feed applications. The soluble α-glucan fiber composition can be blended with one or more additional food ingredients to produce fiber-containing compositions. Methods for the production and use of compositions comprising the soluble α-glucan fiber are also provided.

Polypeptides having the ability to specifically form connections of glucosyl units in alpha 1,3 on an acceptor having at least one hydroxyl moiety are presented. The polypeptides include i) the pattern I of sequence SEQ ID NO: 1, ii) the pattern II of sequence SEQ ID NO: 2, iii) the pattern III of sequence SEQ ID NO: 3, and iv) the pattern IV of sequence SEQ ID NO: 4, or derivates from one or several of said patterns, wherein the polypeptide furthermore has an aspartic residue (D) at position 5 of the pattern II (SEQ ID NO: 2), a glutamic acid residue (E) at position 6 of the pattern III (SEQ ID NO: 3) an an aspartic acid residue (D) at position 6 of the pattern IV (SEQ ID NO: 4). Methods for producing acceptors connected to glucosyl units in alpha 1,3 using the polypeptides are also provided.

Polypeptides having the ability to specifically form connections of glucosyl units in alpha 1,3 on an acceptor having at least one hydroxyl moiety are presented. The polypeptides include i) the pattern I of sequence SEQ ID NO: 1, ii) the pattern II of sequence SEQ ID NO: 2, iii) the pattern III of sequence SEQ ID NO: 3, and iv) the pattern IV of sequence SEQ ID NO: 4, or derivates from one or several of said patterns, wherein the polypeptide furthermore has an aspartic residue (D) at position 5 of the pattern II (SEQ ID NO: 2), a glutamic acid residue (E) at position 6 of the pattern III (SEQ ID NO: 3) an an aspartic acid residue (D) at position 6 of the pattern IV (SEQ ID NO: 4). Methods for producing acceptors connected to glucosyl units in alpha 1,3 using the polypeptides are also provided.

The invention relates to: a protein having dextran-saccharase activity and the sequence SEQ ID NO: 1 for an no acid sequence; a protein having dextran-saccharase activity and the sequence SEQ ID NO: 2 for an amino acid sequence; a complex containing a substrate and a protein with dextran-saccharase activity a method for synthesizing dextrans; and dextrans. The invention also relates to a method for synthesizing gluco-oligosaccharides and gluco-conjugates and to the resulting products.