Purification and characterization of xylitol dehydrogenase with l-arabitol dehydrogenase activity from the newly isolated pentose-fermenting yeast Meyerozyma caribbica 5XY2

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• 作者：Wiphat Sukpipat¹ ; ² ; Hidenobu Komeda² ; ^{hkomeda@pu-toyama.ac.jp} ; Poonsuk Prasertsan¹ ; Yasuhisa Asano² ; ³
• 关键词：Meyerozyma caribbica ; Alcohol fermentation starter ; l-Arabitol dehydrogenase ; Broad polyol specificity ; Xylitol dehydrogenase
• 刊名：Journal of Bioscience and Bioengineering
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：123
• 期：1
• 页码：20-27
• 全文大小：469 K
• 卷排序：123

文摘

Meyerozyma caribbica strain 5XY2, which was isolated from an alcohol fermentation starter in Thailand, was found to catabolize l-arabinose as well as d-glucose and d-xylose. The highest production amounts of ethanol from d-glucose, xylitol from d-xylose, and l-arabitol from l-arabinose were 0.45 g/g d-glucose, 0.60 g/g d-xylose, and 0.61 g/g l-arabinose with 21.7 g/L ethanol, 20.2 g/L xylitol, and 30.3 g/l l-arabitol, respectively. The enzyme with l-arabitol dehydrogenase (LAD) activity was purified from the strain and found to exhibit broad specificity to polyols, such as xylitol, d-sorbitol, ribitol, and l-arabitol. Xylitol was the preferred substrate with Km = 16.1 mM and kcat/Km = 67.0 min−1mM−1, while l-arabitol was also a substrate for the enzyme with Km = 31.1 mM and kcat/Km = 6.5 min−1 mM−1. Therefore, this enzyme from M. caribbica was named xylitol dehydrogenase (McXDH). McXDH had an optimum temperature and pH at 40°C and 9.5, respectively. The McXDH gene included a coding sequence of 1086 bp encoding a putative 362 amino acid protein of 39 kDa with an apparent homopentamer structure. Native McXDH and recombinant McXDH exhibited relative activities toward l-arabitol of approximately 20% that toward xylitol, suggesting the applicability of this enzyme with the functions of XDH and LAD to the development of pentose-fermenting Saccharomyces cerevisiae.