초록
<P><B>Abstract</B></P> <P>Two exoinulinases, Exo-I and Exo-II from the culture broth of <I>Penicillium oxalicum</I> BGPUP-4 was purified using three-step purification method i.e., isopropanol precipitation, Q-Sepharose and Sephadex G-100 column chromatography. The molecular weight of Exo-I and Exo-II was determined to be 64.85 kDa and 32.54 kDa, respectively using MALDI-TOF. Exo-I and Exo-II showed high specificity for inulin and their respective <I>V</I> <SUB>max</SUB>/<I>K</I> <SUB> <I>m</I> </SUB> ratio was 3.74 and 7.20. Besides, both the inulinases also displayed specificity for lactose, sucrose and raffinose. Exo-I and Exo-II were stable at a pH range of 4.0–8.0 with pH optima 5.0. Optimal temperature for both the inulinases was 55 °C, and both the isoforms retained approximately 50% of their activity up to 70 °C. Ag<SUP>+</SUP>, Hg<SUP>2+</SUP>, Ba<SUP>2+</SUP>, Cu<SUP>2+</SUP> and Ca<SUP>2+</SUP> ions shown stimulatory effect on inulinases activity, while Fe<SUP>2+</SUP>, Mn<SUP>2+</SUP>, Co<SUP>2+</SUP>and EDTA completely inhibited enzyme activity. Purified enzyme was successfully used for the preparation of high fructose syrup from inulin.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two isoforms Exo-I and Exo-II were purified from <I>Penicillium oxalicum</I>. </LI> <LI> Both the isoforms were characterized for kinetic and thermodynamic parameters. </LI> <LI> Purified Exo-II was used for the preparation of high fructose syrup. </LI> </UL> </P>