A thermophilic and acid stable family-10 xylanase from the acidophilic fungus Bispora sp. MEY-1

Abstract

A complete gene, xyl10C, encoding a thermophilic endo-1,4-beta-xylanase (XYL10C), was cloned from the acidophilic fungus Bispora sp. MEY-1 and expressed in Pichia pastoris. XYL10C shares highest nucleotide and amino acid sequence identities of 57.3 and 49.7%, respectively, with a putative xylanase from Aspergillus fumigatus Af293 of glycoside hydrolase family 10. A high expression level in P. pastoris (73,400 U ml(-1)) was achieved in a 3.7-l fermenter. The purified recombinant XYL10C was thermophilic, exhibiting maximum activity at 85 degrees C, which is higher than that reported from any fungal xylanase. The enzyme was also highly thermostable, exhibiting approximately 100% of the initial activity after incubation at 80 degrees C for 60 min and >87% of activity at 90 degrees C for 10 min. The half lives of XYL10C at 80 and 85 degrees C were approximately 45 and 3 h, respectively. It had two activity peaks at pH 3.0 and 4.5-5.0 (maximum), respectively, and was very acid stable, retaining more than 80% activity after incubation at pH 1.5-6.0 for 1 h. The enzyme was resistant to Co(2+), Mn(2+), Cr(3+) and Ag(+). The specific activity of XYL10C for oat spelt xylan was 18,831 U mg(-1). It also had wide substrate specificity and produced simple products (65.1% xylose, 25.0% xylobiose and 9.9% xylan polymer) from oat spelt xylan.

Biodiversity, evolution and adaptation of fungi in extreme environments

“…In general, extremozymes have attracted a great deal of interest due to their potential for practical applications. However, studies on fungal acidic enzymes still remain limited with a few exceptions including mannanase, xylanase (Luo et al 2009a(Luo et al , 2009b, and polygalacturonase (Yang et al 2011) from the acidophilic Bispora sp. strain MEY-1, or laccase from H. acidophila (Tetsch et al 2005).…”

Thermostability Improvement of a Streptomyces Xylanase by Introducing Proline and Glutamic Acid Residues

“…A number of thermostable GH10 xylanases have been reported for thermophilic Thermotoga maritima MSB8 (90°C) (10), Thermotoga petrophila RKU-1 (90°C) (11), and Thermobifida alba UL JB1 (80°C) (12) and for acidomesophilic Bispora sp. strain MEY-1 (85°C) (13). The available sequences and structures of these thermophilic xylanases (i.e., 1VBU and 3NIY [10,11]) provide valuable information for better understanding of the structural and functional characters of thermostable enzymes.…”

A Xylanase Gene Directly Cloned from the Genomic DNA of Alkaline Wastewater Sludge Showing Application Potential in the Paper Industry

“…For instance, xylanase XYL10C from acidophilic Bispora sp. MEY-1 that was isolated from the acidic wastewater of a uranium mine had high activity and good stability under acidic conditions (pH 1.5-6.0) [17]. The alkaliphilic Bacillus sp.…”