Microwave pretreatment of paramylon enhances the enzymatic production of soluble β-1,3-glucans with immunostimulatory activity

Alexander Gissibl, Andrew Care, Lindsay M. Parker, Sameera Iqbal, Graham Hobba, Helena Nevalainen, Anwar Sunna*

*Corresponding author for this work

Research output: Contribution to journalArticle

5 Citations (Scopus)


A hydrothermal microwave pretreatment was established to facilitate the enzymatic production of soluble bioactive β-1,3-glucans from the recalcitrant substrate paramylon. The efficacy of this pretreatment was monitored with a newly developed direct Congo Red dye-based assay over a range of temperatures. Microwave pretreatment at 170 °C for 2 min resulted in a significantly enhanced enzymatic hydrolysis of paramylon. The action of endo-β-1,3- and exo- β-1,3-glucanases on the microwave-pretreated paramylon produced soluble β-1,3-glucans with degrees of polymerisation (DP) ranging from 2–59 and 2–7, respectively. In comparison, acid-mediated hydrolysis of untreated paramylon resulted in β-1,3-glucans with a DP range of 2–38. The hydrolysates were assayed on their immunostimulatory effect on murine macrophages by measuring the production of the inflammation-linked marker tumour necrosis factor alpha (TNFα) using immunofluorescence. All of the tested hydrolysis products were shown to induce TNFα production, with the most significant immunostimulatory effect observed with the hydrolysate from the exo-β-1,3-glucanase treatment.

Original languageEnglish
Pages (from-to)339-347
Number of pages9
JournalCarbohydrate Polymers
Publication statusPublished - 15 Sep 2018



  • Paramylon
  • β-1,3-glucans
  • Microwave pretreatment
  • Congo Red dye assay
  • Enzymatic hydrolysis
  • Bioactivity

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