title: Effect of Evolutionary Adaption on Xylosidase Activity in Thermotolerant Yeast Isolates Kluyveromyces marxianus NIRE-K1 and NIRE-K3.
abstract: Efficient use of xylose along with glucose is necessary for the economic production of lignocellulosic based biofuels. Xylose transporters play an important role in the microorganisms for efficient utilization of xylose. In the present study, a novel method has been developed for a rapid assay of xylose transport activity in the xylose-utilizing isolates and other known yeasts. An assay was conducted to compare the activity of β-xylosidase using p-nitrophenyl-β-D-xylopyranoside (pNPX) in the intact, intracellular, and extracellular yeasts cells showing xylose transporter. Saccharomyces cerevisiae (MTCC 170) showed no xylosidase activity, while little growth was observed in the xylose-containing medium. Although other yeasts, i.e., Kluyveromyces marxianus NIRE-K1 (MTCC 5933), K. marxianus NIRE-K3 (MTCC 5934), and Candida tropicalis (MTCC 230), showed xylosidase activity in intact, intracellular, and extracellular culture. The xylosidase activity in intact cell was higher than that of extracellular and intracellular activity in all the yeast cells. The enzyme activity was higher in case of K. marxianus NIRE-K1 and K. marxianus NIRE-K3 rather than the C. tropicalis. Further, better xylosidase activity was observed in adapted K. marxianus cells which were 2.79-28.46 % higher than that of native (non-adapted) strains, which indicates the significant improvement in xylose transportation.
authors.affiliation: Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy (Formerly Sardar Swaran Singh National Institute of Renewable Energy), Kapurthala, Punjab, 144601, India.
authors.forename: Shuvashish
authors.initials: S
authors.lastname: Behera
authors.affiliation: Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy (Formerly Sardar Swaran Singh National Institute of Renewable Energy), Kapurthala, Punjab, 144601, India.
authors.forename: Nilesh K
authors.initials: NK
authors.lastname: Sharma
authors.affiliation: Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy (Formerly Sardar Swaran Singh National Institute of Renewable Energy), Kapurthala, Punjab, 144601, India.
authors.forename: Richa
authors.initials: R
authors.lastname: Arora
authors.affiliation: Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy (Formerly Sardar Swaran Singh National Institute of Renewable Energy), Kapurthala, Punjab, 144601, India. sachin.biotech@gmail.com.
authors.forename: Sachin
authors.identifier: http://orcid.org/0000-0002-6701-6889
authors.initials: S
authors.lastname: Kumar
mesh_terms: D056804:Biofuels; D002175:Candida / Q000201:enzymology; D004795:Enzyme Stability; D007716:Kluyveromyces / Q000201:enzymology; D008031:Lignin / Q000096:biosynthesis / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013696:Temperature; D014995:Xylosidases / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics
chemical_list: D056804:Biofuels; C036909:lignocellulose; D008031:Lignin; D014995:Xylosidases
keywords: Candida tropicalis; Kluyveromyces marxianus; Xylose transport; Yeast; pNPX; β-Xylosidase