title: Generation of xylooligosaccharides from microwave irradiated agroresidues using recombinant thermo-alkali-stable endoxylanase of the polyextremophilic bacterium Bacillus halodurans expressed in Pichia pastoris.
abstract: The recombinant Pichia pastoris harboring the endoxylanase gene (TSEV1xyl) of Bacillus halodurans TSEV1 yielded a high titer of extracellular xylanase (502±23 U ml(-1)) on induction with methanol. The purified recombinant xylanase (TSEV1xyl) displayed optimal activity at 80°C and pH 9.0. The glycosylated recombinant xylanase exhibited higher thermostability (T1/2 of 45 min at 80°C) than the native enzyme (T1/2 of 35 min at 80°C). The agroresidues subjected to pretreatment (soaking in alkali followed by microwave irradiation) liberated xylooligosaccharides (XOS) upon hydrolysis with the recombinant xylanase. The removal of unhydrolyzed agroresidues, xylanase and xylose from the hydrolysate by two-step ultrafiltration led to the purification of XOS as confirmed by TLC as well as HPLC analysis.
authors.affiliation: Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India. Electronic address: vikash.udsc@gmail.com.
authors.forename: Vikash
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India. Electronic address: tsnarayana@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Satyanarayana
mesh_terms: D000383:Agriculture; D000468:Alkalies / Q000494:pharmacology; D001407:Bacillus / Q000187:drug effects / Q000201:enzymology*; D019149:Bioreactors / Q000382:microbiology; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D004043:Dietary Fiber; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D004795:Enzyme Stability / Q000187:drug effects; D005285:Fermentation / Q000187:drug effects; D005965:Glucuronates / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008872:Microwaves; D009844:Oligosaccharides / Q000096:biosynthesis*; D010843:Pichia / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism*; D013696:Temperature
chemical_list: D000468:Alkalies; D004043:Dietary Fiber; D005965:Glucuronates; D009844:Oligosaccharides; D011994:Recombinant Proteins; C570991:xylooligosaccharide; D043364:Endo-1,4-beta Xylanases
keywords: Bacillus halodurans; Microwave irradiation; Pichia pastoris; Polyextremophilic; Xylooligosaccharides