Antimicrobial activity of acidic xylo-oligosaccharides produced by family 10 and 11 endoxylanases

Abstract

Acidic oligosaccharides were obtained from birchwood xylan by treatment with a Thermoascus aurantiacus family 10 and a Sporotrichum thermophile family 11 endoxylanases. The main difference between the products liberated by xylanases of family 10 and 11 concerned the length of the products containing 4-O-methyl-D-glucuronic acid. The xylanase from T. aurantiacus liberate from glucuronoxylan an aldotetrauronic acid as the shortest acidic fragment in contrast with the enzyme from S. thermophile, which liberated an aldopentauronic acid. Acidic xylooligosaccharides were separated from the hydrolysate by anion-exchange and size-exclusion chromatography (SEC) and the primary structure was determined by 13C NMR spectroscopy. The acidic xylo-oligosaccharides were tested against three Gram-positive and three Gram-negative aerobically grown bacteria, as well as against Helicobacter pylori. Aldopentauronic acid was proved more active against the Gram-positive bacteria and against H. pylori.