Biochemical properties of a new thermo- and solvent-stable xylanase recovered using three phase partitioning from the extract of Bacillus oceanisediminis strain SJ3

Nawel Boucherba,Mohamed Yacine Kerbous,Amel Bouanane-Darenfed,Khelifa Bouacem,Cilia Bouiche,Yacine Maafa,Mohammed Gagaoua,Said Benallaoua

doi:10.1186/s40643-017-0161-9

Abstract

The present study investigates the production and partial biochemical characterization of an extracellular thermostable xylanase from the Bacillus oceanisediminis strain SJ3 newly recovered from Algerian soil using three phase partitioning (TPP). The maximum xylanase activity recorded after 2 days of incubation at 37 °C was 20.24 U/ml in the presence of oat spelt xylan. The results indicated that the enzyme recovered in the middle phase of TPP system using the optimum parameters were determined as 50% ammonium sulfate saturation with 1.0:1.5 ratio of crude extract: t-butanol at pH and temperature of 8.0 and 10 °C, respectively. The xylanase was recovered with 3.48 purification fold and 107% activity recovery. The enzyme was optimally active at pH 7.0 and was stable over a broad pH range of 5.0–10. The optimum temperature for xylanase activity was 55 °C and the half-life time at this temperature was of 6 h. At this time point the enzyme retained 50% of its activity after incubation for 2 h at 95 °C. The crude enzyme resist to sodium dodecyl sulfate and β-mercaptoethanol, while all the tested ions do not affect the activity of the enzyme. The recovered enzyme is, at least, stable in tested organic solvents except in propanol where a reduction of 46.5% was observed. Further, the stability of the xylanase was higher in hydrophobic solvents where a maximum stability was observed with cyclohexane. These properties make this enzyme to be highly thermostable and may be suggested as a potential candidate for application in some industrial processes. To the best of our knowledge, this is the first report of xylanase activity and recoverey using three phase partitioning from B. oceanisediminis.

Highlights

Hemicellulose is the second most abundant renewable biomass after cellulose in nature (Collins et al 2005)
Xylan is the major component of hemicelluloses in wood from angiosperms, where it accounts for 15–30% of the total dry weight
At 95 °C the profile obtained for thermostability showed that 50% of the original activity was retained after 2 h exposure, the results clearly indicated that the suitable temperature range for industrial application for xylanase

Summary

Introduction

Hemicellulose is the second most abundant renewable biomass after cellulose in nature (Collins et al 2005). (2017) 4:29 the bioconversion of lignocellulosic material and agrowastes to fermentative products, clarification of juices, improvement in consistency of beer, and the digestibility of animal feed stock (Badhan et al 2007; Elgharbi et al 2015a, b; Shameer 2016; Jain and Krishnan 2017). Due to their important activity at alkaline pH (8.0–11) and high temperature (50–90 °C), thermostable alkaline xylanases have attracted special attention in the pulp biobleaching industry (Techapun et al 2003; Bouacem et al 2014; Boucherba et al 2014; Bouanane-Darenfed et al 2016). Some Bacillus strains have been reported as xylanolytic enzymes producers (Lindner et al 1994; Seo et al 2013; Tarayre et al 2013; Elgharbi et al 2015a; Zouari et al 2015)

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Results

Conclusion