Isomerization of deoxyhexoses: green bioproduction of 1-deoxy-d-tagatose from l-fucose and of 6-deoxy-d-tagatose from d-fucose using Enterobacter agglomerans strain 221e

1-Deoxy-d-tagatose was produced by the hydrogenation of 6-deoxy-l-galactose (l-fucose) to l-fucitol followed by oxidation with Enterobacter agglomerans 221e; a similar sequence on d-fucose afforded 6-deoxy-d-tagatose. Thus, the polylol dehydrogenase recognizes the d-galacto-configuration of both d-fucitol and l-fucitol. The procedures were conducted in water and show the power of green, environmentally friendly biotechnology in the preparation of new monosaccharides with a potential for novel bioactive properties. 6-Deoxy-d-tagatose was also synthesized from d-tagatose via the efficient formation of 1,2:3,4-di-O-isopropylidene-α-d-tagatofuranose; a difficult final removal of protecting groups by acid makes the biotechnological route more attractive.

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1-Deoxy-d-tagatoseC6H12O5Ee = 100%[α]D20=-14.7 (c 1.0, H2O)Source of chirality: l-fucose as starting material

6-Deoxy-d-tagatoseC6H12O5Ee = 100%[α]D20=-2.2 (c 1.0, H2O)Source of chirality: d-fucose as starting material

l-Fucitol: 1-deoxy-d-galactitolC6H14O5Ee = 100%[α]D20=+1.9 (c 1.0, H2O)Source of chirality: l-fucose as starting material

d-Fucitol: 1-deoxy-l-galactitolC6H14O5Ee = 100%[α]D20=-1.9 (c 1.0, H2O)Source of chirality: d-fucose as starting material

1,2:3,4-Di-O-isopropylidene-α-d-tagatofuranoseC12H20O6Ee = 100%[α]D22=+66.3 (c 1.04, CHCl3)Source of chirality: d-tagatose as starting material

1,2:3,4-Di-O-isopropylidene-6-O-trifluoromethanesulfonyl-α-d-tagatofuranoseC13H19F3O8SEe = 100%[α]D22=+43.6 (c 0.89, CHCl3)Source of chirality: d-tagatose as starting material

6-Deoxy-1,2:3,4- di-O-isopropylidene-6-iodo-α-d-tagatofuranoseC12H19IO5Ee = 100%[α]D22=+44.5 (c 0.92, CHCl3)Source of chirality: d-tagatose as starting material

6-Deoxy-1,2;3,4-di-O-isopropylidene-α-d-tagatofuranoseC12H20O5Ee = 100%[α]D22=+64.3 (c 0.96, CHCl3)Source of chirality: d-tagatose as starting material