Characterisation of branched gluco-oligosaccharides to study the mode-of-action of a glucoamylase from Hypocrea jecorina

M.C. Jonathan, M. van Brussel, M.S. Scheffers, M.A. Kabel*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

15 Citations (Scopus)

Abstract

In the conversion of starch to fermentable glucose for bioethanol production, hydrolysis of amylopectin by a-amylases and glucoamylases is the slowest step. In this process, a-1,6-branched gluco-oligosaccharides accumulate and are slowly degraded. Glucoamylases that are able to degrade such branched oligosaccharides faster are economically beneficial. This research aimed at the isolation and characterisation of branched gluco-oligosaccharides produced from amylopectin digestion by a-amylase, to be used as substrates for comparing their degradation by glucoamylases. Branched gluco-oligosaccharides with a DP between five and twelve were purified using size exclusion chromatography. These structures were characterised after labelling with 2-aminobenzamide using UHPLC-MSn analysis. Further, the purified oligosaccharides were used to evaluate the mode-of-action of a glucoamylase from Hypocrea jecorina. The enzyme cleaves the a-1,4-linkage adjacent to the a-1,6-linkage at a lower rate than that of a-1,4-linkages in linear oligosaccharides. Hence, the branched gluco-oligosaccharides are a suitable substrate to evaluate glucoamylase activity on branched structures.
Original languageEnglish
Pages (from-to)59-66
JournalCarbohydrate Polymers
Volume132
Issue number5
DOIs
Publication statusPublished - 2015

Keywords

  • Amylopectin
  • Gluco-oligosaccharide
  • Glucoamylase
  • Maltodextrins

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