Improvement of bread making quality by supplementation with a recombinant xylanase produced by Pichia pastoris

• Published in: PloS one 2018-02, Vol.13 (2), p.e0192996-e0192996
• Main Authors: de Queiroz Brito Cunha, Carolina Cândida, Gama, Aline Rodrigues, Cintra, Lorena Cardoso, Bataus, Luiz Artur Mendes, Ulhoa, Cirano José
• Format: Article
• Language: English
• Subjects: Amino acids; Ascomycota; Avena; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Biology and Life Sciences; Bread; Bread - analysis; Bread mixes; Cloning; Cloning, Molecular; E coli; Electrophoresis, Polyacrylamide Gel; Endo-1,4-beta Xylanases - genetics; Endo-1,4-beta Xylanases - isolation & purification; Endo-1,4-beta Xylanases - metabolism; endo-1,4-β-Xylanase; Enzyme Stability; Enzymes; Escherichia coli; Fagus; Firmness; Food; Food Quality; Genetic aspects; Glycerol; Gram-positive bacteria; Growth hormone; Hydrogen-Ion Concentration; Innovations; Medicine and Health Sciences; Metal ions; Molecular weight; Physical Sciences; Pichia - genetics; Pichia - metabolism; Pichia pastoris; Potassium; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Research and Analysis Methods; Residues; Specific volume; Stiffness; Streptomyces; Streptomyces - enzymology; Streptomyces - genetics; Sugar; Supplementation; Supplements; Temperature; Xylan; Xylanase; Xylanases; Xylans - metabolism; Xylose; Yeast
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0192996

Xylanases (EC 3.2.1.8) are hydrolytic enzymes, which randomly cleave the β-1,4-linked xylose residues from xylan. The synthetic gene xynBS27 from Streptomyces sp. S27 was successfully cloned and expressed in Pichia pastoris. The full-length gene consists of 729 bp and encodes 243 amino acids including 51 residues of a putative signal peptide. This enzyme was purified in two steps and was shown to have a molecular weight of 20 kDa. The purified r-XynBS27 was active against beechwood xylan and oat spelt xylan as expected for GH 11 family. The optimum pH and temperature values for the enzyme were 6.0 and 75 °C, respectively. The Km and Vmax were 12.38 mg/mL and 13.68 μmol min/mg, respectively. The r-XynBS27 showed high xylose tolerance and was inhibited by some metal ions and by SDS. r-XynBS27 was employed as an additive in the bread making process. A decrease in firmness, stiffness and consistency, and improvements in specific volume and reducing sugar content were recorded.