A Highly Thermostable Xylanase fromStenotrophomonas maltophilia: Purification and Partial Characterization

Abstract

Seven xylanolytic bacterial strains were isolated from saw-dust dump soil. The bacterial strain X6 was selected on the basis of the highest xylanase activity with no cellulase contamination. It was identified as Stenotrophomonas maltophilia by biochemical tests and 16S rRNA gene sequencing approach. Xylanase production studies by S. maltophilia on different commercial xylans and agro-industrial residues suggested that wheat bran was the best carbon source for xylanase production (26.4 ± 0.6 IU/mL). The studies with inorganic and organic nitrogen sources suggested yeast extract as the best support for xylanase production (25 ± 0.6 IU/mL). Maximum xylanase production was observed at initial medium pH = 8.0 (23.8 ± 0.4 IU/mL) with production at pH = 7.0 and pH = 9.0 being almost comparable. Xylanase produced by S. maltophilia was purified to homogeneity using ammonium sulfate precipitation, gel filtration, and ion exchange chromatography. The final purification was 5.43-fold with recovery of 19.18%. The molecular weight of the purified xylanase protein was ~142 kDa. Both crude and purified xylanase had good stability at pH = 9.0 and 80°C with activity retention greater than 90% after 30 min incubation. The enzyme stability at high temperature and alkaline pH make it potentially effective for industrial applications.

A detailed overview of xylanases: an emerging biomolecule for current and future prospective

“…(Thomas (Karlsson et al 2004), Streptomyces sp. (Sukhumsirichart et al 2014), Stenotrophomonas maltophila (Raj et al 2013), Thermotoga thermarum (Shi et al 2013). Psychrophilic xylanases are not very common but found to be isolated from several bacteria such as Clostridium sp.…”

Purification, characterization and thermostability improvement of xylanase from Bacillus amyloliquefaciens and its application in pre-bleaching of kraft pulp

“…The supernatant (8000 rpm for 10 min, at 4 °C) were assayed by procedures described by Raj et al (2013a). The quantification of the reducing sugars released from both assays was done according to the DNS method developed by Miller (1959), using calibration curve of d -xylose and d -glucose.…”

“…Although xylanases are produced by a wide range of different microorganisms, yet bacteria, due to their ability to grow and produce xylanases at high pH and temperature with minimum or no cellulase production, are widely exploited for xylanase production for industrial applications (Bajaj and Manhas 2012; Dhiman et al 2008; Raj et al 2013a). Despite the extensive search for microbial diversity for novel xylanase producers, however, xylanases with thermo and alkali stability are limited (Bajaj et al 2011) and there remains a strong need for thermostable xylanases.…”

Screening of Culture Conditions for Production of Xylanase from Landfill Soil Bacteria

“…This information is important to further the works into the optimization stage to give positive impact in the growth of microorganisms and to synthesize the desirable xylanase at maximum level with improvement in its production process [12]. Previously, xylanase was produced either by using commercial substrates such as xylan [13], birchwood xylan [14][15], and glucose [7] or by utilizing cheaper substrates such as rice straw [16], rice bran [17], wheat bran [5,[17][18][19][20], wheat straw [21], orange peel, banana peel, mango peel, apple pulp, oil cake [7], grass extract [22], sugarcane sheath leaf extract [22], Prosopis juliflora pods [23], olive mill waste, olive leaves, sawdust, corn cobs [18], barley husk [6], sugarcane bagasse [24] and apple pomace [25] supplemented with other nutrient sources in submerged fermentation [7,[13][14][15][16][17][20][21][22][23][24] or in solid state fermentation [5,[18][19]25] modes. The xylanase is produced by microorganisms such as Streptomyces thermovulgaris TISTR1948 [16], Bacillus sp.…”