title: Functional characterisation of a recombinant xylanase from Pichia pastoris and effect of the enzyme on nutrient digestibility in weaned pigs.
abstract: The xyn2 gene of a filamentous mesophilic fungus, Trichoderma reesei, coding xylanase 2 (Xyn2) was previously expressed in Pichia pastoris. In the present study, the recombinant Xyn2 was prepared from a 15 litre fermenter, and subsequently characterised. It has been confirmed to have a molecular mass of 21 kDa, an optimal pH of 6.0 and an optimal temperature of 60 degrees C. When tested using oat-spelt xylan, it showed a Km and catalytic rate constant (kcat) of 1.1 mg/ml and 512.4/s, respectively. Analysis of the products from oat-spelt xylan degradation confirmed that the enzyme was an endoxylanase with xylotriose and xylobiose as the main degradation products. The unprocessed Xyn2 was supplemented to a xylan-containing diet to determine its influences on performance and nutrient digestibilities by weaned pigs. Results showed that the average body-weight gain increased 16.9 % when piglets received Xyn2 at a concentration of 500 U/kg diet. There also was a positive (0.05 < P < 0.10) effect on the digestibility values of crude protein, ash, Ca and acid-detergent fibre with Xyn2 supplementation. The potential benefits of Xyn2 in the nutrition of weaned pigs should make it an alternative applicant for industrial xylanase production.
authors.affiliation: Institute of Animal Nutrition, Sichuan Agricultural University, Yaan, Sichuan 625014, China.
authors.forename: Jun
authors.initials: J
authors.lastname: He
authors.forename: Jia
authors.initials: J
authors.lastname: Yin
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Bing
authors.initials: B
authors.lastname: Yu
authors.forename: Daiwen
authors.initials: D
authors.lastname: Chen
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary; D004063:Digestion / Q000502:physiology*; D005260:Female; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008297:Male; D010843:Pichia / Q000201:enzymology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D013552:Swine / Q000254:growth & development / Q000502:physiology*; D013696:Temperature; D014886:Weaning; D014995:Xylosidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D014995:Xylosidases