Abstract
In order to search for high specific activity and the resistant xylanases to XIP-I and provide more alternative xylanases for industrial production, a strain of Fusarium graminearum from Triticum aestivum grains infected with filamentous fungus produced xylanases was isolated and identified. Three xylanase genes from Fusarium graminearum Z-1 were cloned and successfully expressed in E. coli and P. pastoris, respectively. The specific activities of Fgxyn1, (E)Fgxyn2 and (E)Fgxyn3 for birchwood xylan were 38.79, 0.85 and 243.83 U/mg in E. coli, and 40.11, 0 and 910.37 U/mg in P. pastoris, respectively. (E)Fgxyn3 and (P)Fgxyn3 had the similar optimum pH at 6.0 and pH stability at 5.0-9.0. However, they had different optimum temperature and thermal stability, with 30 °C for (E)Fgxyn3 and 40 °C for (P)Fgxyn3, and 4-35 °C for (E)Fgxyn3 and 4-40 °C for (P)Fgxyn3, respectively. The substrate spectrum and the kinetic parameters showed that the two xylanases also exhibited the highest xylanase activity and catalytic efficiency (k(cat)/k(m)) toward birchwood xylan, with 243.83 U/mg and 61.44 mL/mg/s for (E)Fgxyn3 and 910.37 U/mg and 910.37 mL/mg/s for (P)Fgxyn3, respectively. This study provided a novel mesophilic xylanase with high specific activity and catalytic efficiency, thus making it a promising candidate for extensive applications in animal feed and food industry. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-024-03973-0.