Single-step purification and characterization of an extreme halophilic, ethanol tolerant and acidophilic xylanase from Aureobasidium pullulans NRRL Y-2311-1 with application potential in the food industry

•An extracellular xylanase from Aureobasidium pullulans was produced on wheat bran.•A single step, low cost chromatographic procedure was applied for purification.•Xylanase was purified 3.4 fold with 80% recovery to apparent homogeneity.•Novel properties of the Aureobasidium pullulans xylanase were elucidated.•The enzyme was extreme halophilic, ethanol tolerant and acidophilic.

An extracellular xylanase from Aureobasidium pullulans NRRL Y-2311-1 produced on wheat bran was purified by a single-step chromatographic procedure. The enzyme had a molecular weight of 21.6 kDa. The optimum pH and temperature for xylanase activity were 4.0 and 30-50°C, respectively. The enzyme was stable in the pH range of 3.0-8.0. The inactivation energy of the enzyme was calculated as 218 kJ mol−1. The xylanase was ethanol tolerant and kept complete activity in the presence of 10% ethanol. Likewise, it retained almost complete activity at a concentration range of 0-20% NaCl. In general, the enzyme was resistant to several metal ions and reagents. Mg2+, Zn2+, Cu2+, K1+, EDTA and β-mercaptoethanol resulted in enhanced xylanase activity. The Km and Vmax values on beechwood xylan were determined to be 19.43 mg ml−1 and 848.4 U ml−1, respectively. The enzyme exhibits excellent characteristics and could, therefore, be a promising candidate for application in food and bio-industries.

Graphical abstractDownload high-res image (156KB)Download full-size image