Disclosed is a method for producing 2′-fucosyllactose from a recombinant Corynebacterium sp. introduced with fucosyltransferase derived from Pseudopedobacter saltans. The recombinant Corynebacterium sp. microorganism introduced with fucosyltransferase derived from Pseudopedobacter saltans is capable of producing 2′-fucosyllactose at a high concentration, high yield and high productivity.

Disclosed is a method for producing 2′-fucosyllactose from a recombinant Corynebacterium sp. introduced with fucosyltransferase derived from Pseudopedobacter saltans. The recombinant Corynebacterium sp. microorganism introduced with fucosyltransferase derived from Pseudopedobacter saltans is capable of producing 2′-fucosyllactose at a high concentration, high yield and high productivity.

The present invention relates to a temperature optimized L-arabinose isomerase with a high catalytic activity within feedstocks comprising a high concentration of divalent metal ions, a nucleic acid sequence encoding the inventive L-arabinose isomerase, a vector comprising the nucleic acid sequence encoding the inventive L-arabinose isomerase, a composition containing the inventive L-arabinose isomerase, a yeast cell comprising the inventive L- arabinose isomerase, the use of the inventive L-arabinose isomerase, the composition or the yeast cell for the fermentation of feedstock with a high content of divalent metal ions.

The present invention relates to a temperature optimized L-arabinose isomerase with a high catalytic activity within feedstocks comprising a high concentration of divalent metal ions, a nucleic acid sequence encoding the inventive L-arabinose isomerase, a vector comprising the nucleic acid sequence encoding the inventive L-arabinose isomerase, a composition containing the inventive L-arabinose isomerase, a yeast cell comprising the inventive L- arabinose isomerase, the use of the inventive L-arabinose isomerase, the composition or the yeast cell for the fermentation of feedstock with a high content of divalent metal ions.

Provided herein are methods for identifying and isolating polynucleotides coding for polypeptides having D-allulose 3-epimerase activity from a wide variety of microorganisms. Also provided are nucleic acid constructs, vectors and recombinant host cells comprising the polynucleotides coding for D-allulose 3-epimerase activity as well as methods for producing allulose from fructose using said recombinant host cells having D-allulose 3-epimerase activity or the D-allulose 3-epimerase enzyme of said recombinant host cells having D-allulose 3-epimerase activity.

Provided herein are methods for identifying and isolating polynucleotides coding for polypeptides having D-allulose 3-epimerase activity from a wide variety of microorganisms. Also provided are nucleic acid constructs, vectors and recombinant host cells comprising the polynucleotides coding for D-allulose 3-epimerase activity as well as methods for producing allulose from fructose using said recombinant host cells having D-allulose 3-epimerase activity or the D-allulose 3-epimerase enzyme of said recombinant host cells having D-allulose 3-epimerase activity.

An object of the present invention is to provide an enzyme preparation that efficiently catalyzes the epimerization reaction with little byproducts. The present invention provides an enzyme preparation for catalyzing an epimerization reaction of a saccharide, which contains any of the proteins (a) to (c) mentioned below, and wherein the saccharide is any selected from the group consisting of glucose, mannose, talose and galactose: (a) a protein consisting of the amino acid sequence of SEQ ID NO: 1 or 3; (b) a protein consisting of an amino acid sequence having an amino acid sequence identity of 90% or higher to the amino acid sequence of SEQ ID NO: 1 or 3, and having an activity for catalyzing an epimerization reaction of a saccharide; and (c) a protein consisting of an amino acid sequence derived from the amino acid sequence of SEQ ID NO: 1 or 3 by substitution, insertion, deletion and/or addition of one or several amino acids, and having an activity for catalyzing an epimerization reaction of a saccharide.

The disclosure discloses genetically engineered bacteria producing lacto-N-neotetraose and a production method thereof, and belongs to the fields of metabolic engineering and food biotechnology. To solve the problem of low yield of lacto-N-neotetraose produced by a microbial method in the prior art, through exogenous expression of lgtA and lgtB, reasonable combination and regulation of overexpression of lacY, pgm, galE, galT and galK in a lacto-N-neotetraose synthesis pathway, knockout of lacZ expression in an Escherichia coli host, and optimization of a carbon source in the culture process, the disclosure achieves the objectives of regulating the carbon flux of a metabolic pathway and improving the yield of lacto-N-neotetraose. In a shake flask experiment, the yield of lacto-N-neotetraose produced by E. coli increased from 304 mg/L to 1031 mg/L, laying a foundation for industrial production of the lacto-N-neotetraose.

Provided are a tagatose-bisphosphate aldolase variant having tagatose conversion activity, and a method of preparing tagatose using the same.

A genetically modified Bacillus subtilis strain has been transformed with an optimized vector, mainly for producing a D-psicose 3-epimerase.