Purification and characterization of xylitol dehydrogenase with L-arabitol dehydrogenase activity from the newly isolated pentose-fermenting yeast Meyerozyma caribbica 5XY2
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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DOI：
10.1016/j.jbiosc.2016.07.011
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发表时间：
2017-01-01
影响因子：
2.8
通讯作者：
Asano, Yasuhisa
中科院分区：
文献类型：
--
作者：
Sukpipat, Wiphat;Komeda, Hidenobu;Asano, Yasuhisa
从泰国的一种酒精发酵剂中分离到一株产L-阿拉伯糖、α-葡萄糖和D-木糖的卡里毕卡酵母（Meyerozyma caribbica）5XY 2。当乙醇浓度为21.7 g/L、木糖醇浓度为20.2 g/L、L-阿拉伯糖醇浓度为303 g/L时，D-葡萄糖、木糖醇和L-阿拉伯糖的最高乙醇产量分别为0.45 g/g D-葡萄糖、0.60 g/g D-木糖和0.61 g/g L-阿拉伯糖。从该菌株中纯化出具有L-阿拉伯糖醇脱氢酶（LAD）活性的酶，发现该酶对木糖醇、D-山梨糖醇、核糖醇和L-阿拉伯糖醇等多元醇具有广泛的特异性。木糖醇是优选的底物，K-m = 16.1 mM和k（cat）/K-m = 67.0 min（-1）mM（-1），而L-阿拉伯糖醇也是该酶的底物，K-m = 31.1 mM和k（cat）/K-m = 6.5 min（-1）mM（-1）。因此，该酶从M.将其命名为木糖醇脱氢酶（McXDH）。McXDH的最适温度和pH分别为40 ℃和9.5。McXDH基因全长1086 bp，编码362个氨基酸，分子量为39 kDa，具有明显的同源五聚体结构。天然McXDH和重组McXDH对L-阿拉伯糖醇的相对活性约为对木糖醇的20%，这表明该酶具有XDH和LAD的功能，可用于戊糖发酵酿酒酵母的开发。(C)2016年，日本生物技术学会。All rights reserved.
Meyerozyma caribbica strain 5XY2, which was isolated from an alcohol fermentation starter in Thailand, was found to catabolize L-arabinose as well as a-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 xylitol, and 303 g/1 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 K-m = 16.1 mM and k(cat)/K-m = 67.0 min(-1)mM(-1), while L-arabitol was also a substrate for the enzyme with K-m = 31.1 mM and k(cat)/K-m = 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 degrees 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. (C) 2016, The Society for Biotechnology, Japan. All rights reserved.