The present invention relates to a method for producing trehalose, comprising the steps of mixing and reacting, in any order, (i) at least one alpha-phosphorylase capable of catalyzing the production of alpha-D-glucose 1-phosphate intermediate from a saccharide raw material, and from at least one phosphorus source; (ii) at least one trehalose phosphorylase capable of catalyzing the production of trehalose from an alpha-D-glucose 1-phosphate intermediate and a glucose substrate, wherein the trehalose phosphorylase is a trehalose phosphorylase variant with an amino acid sequence which differs from the amino acid sequence of a wild type trehalose phosphorylase in at least one amino acid position, (iii) at least one saccharide raw material which produces an alpha-D-glucose 1-phosphate intermediate and a co-product by catalytic action of the alpha-phosphorylase; and (iv) at least one phosphorus source selected from the group consisting of a phosphoric acids and an inorganic salt thereof.

The present invention relates to a method for producing trehalose, comprising the steps of mixing and reacting, in any order, (i) at least one alpha-phosphorylase capable of catalyzing the production of alpha-D-glucose 1-phosphate intermediate from a saccharide raw material, and from at least one phosphorus source; (ii) at least one trehalose phosphorylase capable of catalyzing the production of trehalose from an alpha-D-glucose 1-phosphate intermediate and a glucose substrate, wherein the trehalose phosphorylase is a trehalose phosphorylase variant with an amino acid sequence which differs from the amino acid sequence of a wild type trehalose phosphorylase in at least one amino acid position, (iii) at least one saccharide raw material which produces an alpha-D-glucose 1-phosphate intermediate and a co-product by catalytic action of the alpha-phosphorylase; and (iv) at least one phosphorus source selected from the group consisting of a phosphoric acids and an inorganic salt thereof.

The present invention provides for a nucleic acid encoding an isomerase and uses of the isomerase for bioconversion of sugar substrates. The invention represents an advancement in the field of enzyme engineering and discloses a modified nucleic acid for achieving optimum expression of a protein having isomerase activity in a heterologous host. The invention also discloses vectors carrying the modified nucleic acid and recombinant host cells carrying the vectors. The invention also discloses the process for producing a recombinant host cell, process for production of the recombinant enzyme and the process for bioconversion of sugars into their respective isomers using the recombinant protein.

The present invention provides for a nucleic acid encoding an isomerase and uses of the isomerase for bioconversion of sugar substrates. The invention represents an advancement in the field of enzyme engineering and discloses a modified nucleic acid for achieving optimum expression of a protein having isomerase activity in a heterologous host. The invention also discloses vectors carrying the modified nucleic acid and recombinant host cells carrying the vectors. The invention also discloses the process for producing a recombinant host cell, process for production of the recombinant enzyme and the process for bioconversion of sugars into their respective isomers using the recombinant protein.

Provided herein, in some embodiments, are cell-free systems, methods, kits, and compositions (e.g., cells and cell lysates) for converting a polysaccharide to allulose via the use of enzymes, such as thermostable enzymes.

The invention is in the field of enzymology. More in particular, it provides a method for the isomerization of glucose into fructose wherein the glucose is derived from lignocellulosic material. More in particular, the invention provides polypeptides encoding mutant glucose isomerase enzymes with improved glucose isomerase activity as compared to the corresponding wild type enzyme. The disclosed polypeptides are particularly suited for converting glucose to fructose in the presence of xylose.

The invention is in the field of enzymology. More in particular, it provides a method for the isomerization of glucose into fructose wherein the glucose is derived from lignocellulosic material. More in particular, the invention provides polypeptides encoding mutant glucose isomerase enzymes with improved glucose isomerase activity as compared to the corresponding wild type enzyme. The disclosed polypeptides are particularly suited for converting glucose to fructose in the presence of xylose.

Provided are excellent L-arabinose metabolic genes that function in yeasts. Provided is an L-arabinose metabolic gene cluster including an L-arabinose isomerase gene specified by a predetermined SEQ ID, an L-ribulokinase gene specified by a predetermined SEQ ID, and an L-ribulose-5-phosphate-4-epimerase gene specified by a predetermined SEQ ID.

Provided are excellent L-arabinose metabolic genes that function in yeasts. Provided is an L-arabinose metabolic gene cluster including an L-arabinose isomerase gene specified by a predetermined SEQ ID, an L-ribulokinase gene specified by a predetermined SEQ ID, and an L-ribulose-5-phosphate-4-epimerase gene specified by a predetermined SEQ ID.

A membranous immobilized cell, polypeptide, oligopeptide or protein and a preparation method thereof are provided. The method includes the following steps: 1) providing un-film-form chitosan, where the chitosan is un-pre-crosslinked or pre-crosslinked; 2) providing a mixture of the un-film-form chitosan and cell, polypeptide, oligopeptide or protein, and in the mixture, the un-film-form chitosan is in a dissolved state; 3) mixing the mixture with a crosslinking reagent to obtain a co-crosslinked product of the chitosan and the cell, polypeptide, oligopeptide or protein; and 4) drying the co-crosslinked product to obtain membranous immobilized cell, polypeptide, oligopeptide or protein. When un-pre-crosslinked chitosan is used in the step 1), the method further includes comprises the step 5) mixing the membranous immobilized cell, polypeptide, oligopeptide or protein with phosphate salt, so that chitosan molecules therein are crosslinked with each other.