Expression and Characterization of Hyperthermotolerant Xylanases, SyXyn11P and SyXyn11E, in Pichia pastoris and Escherichia coli

• Published in: Applied biochemistry and biotechnology Vol. 172; no. 7; pp. 3476 - 3487
• Main Authors: Li, Jianfang, Zhang, Huimin, Wu, Minchen, Wang, Chunjuan, Dong, Yunhai, Zhu, Lijuan, Zhang, Peng
• Format: Journal Article
• Language: English
• Published: Boston Springer-Verlag 01.04.2014; Springer US; Springer Nature B.V
• Subjects: Amino Acid Sequence; Base Sequence; Biochemistry; Biotechnology; Chemistry; Chemistry and Materials Science; Cloning, Molecular; corn cobs; E coli; EDTA (chelating agent); Endo-1,4-beta Xylanases - chemistry; Endo-1,4-beta Xylanases - genetics; Endo-1,4-beta Xylanases - metabolism; Enzyme Stability; Enzymes; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Gene Expression; genes; Genes, Synthetic; glycosides; high performance liquid chromatography; Hot Temperature; Hydrogen-Ion Concentration; Kinetics; Liquid chromatography; manganese; metal ions; Molecular Sequence Data; Pichia - genetics; Pichia - metabolism; Pichia pastoris; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; silver; temperature; xylan; xylanases; vector; pPIC9K; Hyperthermotolerant xylanase; Xylooligosaccharides; Codon optimization
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1007/s12010-014-0786-5

Both Syxyn11P and Syxyn11E, two codon-optimized genes encoding glycoside hydrolase (GH) family 11 hyperthermotolerant xylanases (designated SyXyn11P and SyXyn11E), were synthesized and inserted into pPIC9Kᴹ and pET-28a(+) vectors, respectively. The resulting recombinant expression vectors, pPIC9Kᴹ-Syxyn11P and pET-28a(+)-Syxyn11E, were transformed into Pichia pastoris GS115 and Escherichia coli BL21, respectively. The maximum activities of two recombinant xylanases (reSyXyn11P and reSyXyn11E) expressed in P. pastoris and E. coli reached 30.9 and 17.8 U/ml, respectively. The purified reSyXyn11P and reSyXyn11E displayed the same pH optimum at 6.5 and pH stability at a broad range of 4.5–9.0. The temperature optimum and stability of reSyXyn11P were 85 and 80 °C, higher than those of reSyXyn11E, respectively. Their activities were not significantly affected by metal ions tested and EDTA, but strongly inhibited by Mn²⁺ and Ag⁺. The K ₘ and V ₘₐₓ of reSyXyn11P toward birchwood xylan were 4.3 mg/ml and 694.6 U/mg, whose K ₘ was close to that (4.8 mg/ml), but whose V ₘₐₓ was much higher than that (205.6 U/mg) of reSyXyn11E. High-performance liquid chromatography analysis indicated that xylobiose and xylotriose as the major products were excised from insoluble corncob xylan by reSyXyn11P.