Alcohol oxidase (AOX) functions in oxidation of primary alcohols into the corresponding aldehydes with potential on catalyzing synthesis reactions in chemical industry. In this study, AOX from a thermotolerant methylotrophic yeast, Ogataea thermomethanolica (OthAOX) was purified to high homogeneity using a single step chromatographic separation on a DEAE-Sepharose column. The purified OthAOX had a specific activity of 15.34 U/mg with 77.5% recovery yield. The enzyme worked optimally at 50 °C in an alkaline range (pH 9.0). According to kinetic analysis, OthAOX showed a higher affinity toward short-chain aliphatic primary alcohol with the Vmax, Km, and kcat of 0.24 nmol/min, 0.27 mM, and 3628.8 min-1, respectively against methanol. Addition of alginic acid (0.35%) showed a protective effect on enhancing thermal stability of the enzyme, resulting in 72% increase in its half-life at 40 °C under the operational conditions. This enzyme represents a promising candidate for conversion of bioethanol to acetaldehyde as secondary chemical in biorefinery.
Keywords: Alcohol oxidase; Aldehyde; Biorefinery; Ethanol conversion; Ogataea thermomethanolica.
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