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

Autor: Wiphat Sukpipat, Hidenobu Komeda, Poonsuk Prasertsan, Yasuhisa Asano
Rok vydání: 2017
Předmět:
Zdroj: Journal of Bioscience and Bioengineering. 123:20-27
ISSN: 1389-1723
DOI: 10.1016/j.jbiosc.2016.07.011
Popis: 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.
Databáze: OpenAIRE
Externí odkaz: