Construction of new variants of dextransucrase DSR-S by genetic engineering

摘要

The present invention relates to a recombinant process for the production of truncated and/or mutated dextransucrases while conserving their enzymatic activity and/or their specificity in the synthesis of the ±-1,6 bonds. More precisely, the present invention relates to nucleic acid sequences of truncated and/or mutated dextransucrases, vectors containing said nucleic acid sequences and host cells transformed by sequences encoding truncated and/or mutated dextransucrases. In a further aspect, the invention concerns a method for producing, in a recombinant manner, truncated and/or mutated dextransucrases which conserve their enzymatic activity and/or which conserve their specificity in the synthsis of ±-1,6 bonds and however can produce, from saccharose, dextrans with high molar mass and with modified rheological properties, compared with the properties of dextran obtained with the native enzyme in the same conditions and isomalto-oligosaccharides with a controlled molar mass and dextrans. The dextrans and IMO of the invention can be used namely as texturing agents or as prebiotics.