초록
<P><B>Abstract</B></P> <P>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 <I>endo</I>-β-1,3- and <I>exo</I>- 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 <I>exo</I>-β-1,3-glucanase treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new combined physical and enzymatic approach for the hydrolysis of paramylon was developed. </LI> <LI> Microwave pretreatment enhance enzymatic hydrolysis of paramylon. </LI> <LI> Microwave pretreatment of paramylon can be monitored with a new dye-based assay. </LI> <LI> Soluble β-1,3-glucans with immunostimulatory activity were obtained. </LI> </UL> </P>