Methods and compositions for preparing tagatose from fructose

Inventors

Zanghellini, Alexandre • Roberts, Kyle • Cockrem, Michael Charles Milner • DUNCKLEY, Christopher

Assignees

ARZEDA CORP

Abstract

Disclosed herein are compositions and methods for preparing tagatose from fructose, more particularly, compositions comprising thermophilic fructose C4-epimerases derived from thermophilic microorganisms and methods for preparing tagatose from fructose using the compositions.

Core Innovation

The invention relates to D-fructose C4-epimerase polypeptides for producing D-tagatose from fructose by fructose C4-epimerization. The disclosed embodiments include modified polypeptides in which one or more modifications are made as compared to an unmodified polypeptide, with the unmodified polypeptide being SEQ ID NO: 6. The modified polypeptide converts fructose directly to tagatose through epimerization at the carbon-4 position of the fructose.

The modified polypeptides are defined by sequence identity thresholds relative to SEQ ID NO: 6 and by specified amino-acid residues at particular positions. In the representative claims, the modified polypeptide comprises at least 90% identity to SEQ ID NO: 6 or at least 85% identity to SEQ ID NO: 6, and includes H at position 85, D at position 121, H at position 247, D at position 250, and G at position 271, with P at position 75 in one set of residues.

The disclosure also includes polynucleotides and microorganisms expressing the thermophilic D-fructose C4-epimerase polypeptides, together with compositions where the enzyme or expressing microorganism is immobilized on a carrier/support. The document additionally describes tagatose compositions produced from fructose-containing starting compositions by contacting fructose with the polypeptide and converting via C4 epimerization, with downstream separation/purification and optional crystallization.

Claims Coverage

The patent contains two independent claims, each directed to a method of producing tagatose by contacting fructose with a modified polypeptide. Across the independent claims, the coverage focuses on direct conversion via fructose carbon-4 epimerization and defines the modified polypeptide by sequence identity to SEQ ID NO: 6 together with specific amino-acid residues at defined positions.

Both independent claims are anchored on contacting fructose with a modified polypeptide derived from SEQ ID NO: 6, where the modified polypeptide directly converts fructose to tagatose via carbon-4 epimerization. Each independent claim limits the modified polypeptide by a specified sequence identity threshold and by a defined set of amino-acid residues at defined positions.

Stated Advantages

Documented Applications