Abstract: The gene poabf62a encoding an arabinofurosidase from Penicillium oxalicum was codon optimized,chemically synthesized and expressed in Pichia pastoris GS115 and the recombinant enzyme was characterized. To further improve the expression level,the fermentation condition was optimized. The optimal reaction pH and temperature of the recombinant PoAbf62A on pNPAF were 4.5 and 40 ℃,respectively. The enzyme was stable at pH 4.5 and 40~45 ℃. Metal ions,such as Al3+,Co2+,Zn2+,Mg2+ could enhance its activity,while inhibited by Fe3+,Mn2+,Cu2+ and Fe2+. The Km value was 2.46 mmol/L,the Vmax was 9.05 μmol/(min·g),and the kcat was 0.22/s. The optimized fermentation parameters were as follows: inoculating size of the exponential growth phase cells from BMGY to BMMY with primary OD600 of 2.4,methanol supplemented with 1.05% of φ(methanol) every 24 h. As a result,the enzyme activity was 0.51 U/mL after 120 h fermentation at 30.5 ℃,which was 3.25 times higher.
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