Expression of an Aspergillus niger xylanase in yeast: Application in breadmaking and in vitro digestion.
The cDNA of the β-1,4-endoxylanase of Aspergillus niger US368 was cloned and expressed in Pichia pastoris under the constitutive GAP promoter. The maximum activity obtained was 41 U mL(-1), which was about 3-fold higher than that obtained with the native species. The purified enzyme showed a specific activity of 910 U mg(-1) and a molecular mass of 24 kDa. It had an optimal activity at pH 4 and 50 °C, stable in a wide range of pH and in the presence of some detergents and organic solvents. r-XAn11-His6 (recombinant xylanase) was used as an additive in breadmaking. A decrease in water absorption, an increase in dough rising and improvements in volume and specific volume of the bread were recorded. The r-XAn11-His6 was also used in in vitro digestion of barley and wheat bran leading to a decrease of the viscosities and an increase of the reducing sugars and total sugars contents.
Laboratoire de Biotechnologie Microbienne et Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia.
Fatma
F
Elgharbi
Laboratoire de Biotechnologie Microbienne et Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia. Electronic address: aidahmida@yahoo.fr.
Aïda
A
Hmida-Sayari
Laboratoire de Biotechnologie Microbienne et Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia.
Youssef
Y
Zaafouri
Laboratoire de Biotechnologie Microbienne et Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia.
Samir
S
Bejar
D001234:Aspergillus niger / Q000737:chemistry* / Q000201:enzymology; D001939:Bread; D003001:Cloning, Molecular; D003296:Cooking / Q000379:methods; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics; D013696:Temperature; D014783:Viscosity
D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D043364:Endo-1,4-beta Xylanases
Breadmaking; In vitro digestion; Xylanase