Characteristics of levan fructotransferase from Arthrobacter ureafaciens K2032 and difructose anhydride IV formation from levan

A microorganism producing levan fructotransferase was isolated from sugar-d isclosed soil and it was identified as Arthrobacter ureafaciens. The major product from levan by enzyme reaction was identified as di-D-fructofuranose 2,6':6,2' dianhydride by mass spectrometry. nuclear magnetic resonance, an d chemical analyses. Small amounts of several oligosaccharides and free fru ctose were also formed by enzyme reaction. An extracellular enzyme that pro duces di-D-fructofuranose 2,6':6,2' dianhydride from levan was purified fro m the culture broth of A. ureafaciens K2032. The enzyme had optimum activit y around pH 5.8 and 45 degrees C and had a dimeric form in solution. The N- terminal amino acid residues of the purified enzyme were SAPGSLRAVYYHMTPPSG XLXDPQ. The enzyme has narrow substrate range and converts the levan to di- D-fructofuranose 2,6':6,2' dianhydride with around 62.5% conversion yield. (C) 2000 Elsevier Science Inc. All rights reserved.