title: High level expression of a recombinant xylanase by Pichia pastoris NC38 in a 5 L fermenter and its efficiency in biobleaching of bagasse pulp.
abstract: A genetically modified XynA gene from Thermomyces lanuginosus was expressed in Pichia pastoris under the control of GAP promoter. P. pastoris expressed greater levels of xylanase (160 IU ml(-1)) on BMGY medium without zeocin after 56 h. The xylanase production by recombinant P. pastoris was scaled up in a 5L fermenter containing 1% glycerol and the highest xylanase production of 139 IU ml(-1) was observed after 72 h. Further studies carried out in fermenter under controlled pH (5.5) yielded a maximum xylanase production of 177 IU ml(-1) after 72 h. The biobleaching efficacy of crude xylanase was also evaluated on bagasse pulp and a brightness of 47.4% was observed with 50 IU of crude xylanase used per gram of pulp, which was 2.1 points higher in brightness than the untreated samples. Reducing sugars (24.8 mg g(-1)) and UV absorbing lignin-derived compounds values were considerably higher with xylanase treated samples.
authors.affiliation: Department of Biotechnology and Food Technology, Faculty of Applied Sciences, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa.
authors.forename: Natasha
authors.initials: N
authors.lastname: Birijlall
authors.forename: Ayyachamy
authors.initials: A
authors.lastname: Manimaran
authors.forename: Kuttanpillai Santhosh
authors.initials: KS
authors.lastname: Kumar
authors.forename: Kugen
authors.initials: K
authors.lastname: Permaul
authors.forename: Suren
authors.initials: S
authors.lastname: Singh
mesh_terms: D002482:Cellulose / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism; D010843:Pichia / Q000201:enzymology* / Q000254:growth & development; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D002482:Cellulose; C027433:bagasse; D043364:Endo-1,4-beta Xylanases; D005990:Glycerol