Purification and characterization of xylitol dehydrogenase with l-arabitol dehydrogenase activity from the newly isolated pentose-fermenting yeast Meyerozyma caribbica 5XY2.
J Biosci Bioeng
; 123(1): 20-27, 2017 Jan.
Article
in En
| MEDLINE
| ID: mdl-27506274
ABSTRACT
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.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pentoses
/
Sugar Alcohol Dehydrogenases
/
Saccharomycetales
/
D-Xylulose Reductase
/
Fermentation
Language:
En
Journal:
J Biosci Bioeng
Journal subject:
ENGENHARIA BIOMEDICA
/
MICROBIOLOGIA
Year:
2017
Document type:
Article
Affiliation country: