An Eco-friendly Method of Purification for Xylanase from Aspergillus niger by Polyelectrolyte Precipitation

PODESTÁ, MARÍA VICTORIA; MORILLA, ESTEBAN AMADOR; ALLASIA, MARÍA BELÉN; WOITOVICH VALETTI, NADIA; TUBIO, GISELA; BOGGIONE, MARÍA JULIA

JOURNAL OF POLYMERS AND THE ENVIRONMENT

SPRINGER/PLENUM PUBLISHERS

Año: 2019

1566-2543

The separation of xylanase (Xyl) from a fungal extract obtained by submerged fermentation (SmF) was carried out usingprecipitation with natural polyelectrolytes ɩ-carrageenan (Carr) and chitosan (CHS). Xyl activity determined from the fungalextract at different times was modeled by mixed linear model for longitudinal data considering the factors as fixed effectsand the experimental units as random effects. A spline regression was used to model the Xyl activity with knots at days 2and 3 and interaction between three factors (p < 0.0001 in each section). High purification factors were reached with bothpolymers. Mass spectrometry analysis and zymogram analysis revealed that the Xyl that precipitated with both polymershad a molecular weight of 24 kDa and an isoelectric point (pI) of 5.45. The purification factor (PF) of Xyl in the precipitateof the fungal extract from SmF with 0.05% w/v CHS (pH 8.00) was around 5.6 for a mass ratio of 1.8 × 10−5 mg CHS/mgprotein and with 0.5% w/v Carr (pH 7.00) it was 9.0 for a mass ratio of 0.03 mg Carr/mg protein. These results make thisprecipitation method suitable to be included in a downstream process, providing such advantages as simplicity, scalability,ability to concentrate the enzyme in a single step process as well as the use non-toxic reagents. Taking into account that theprocess of purification of macromolecules is a decisive step with a profound impact on their final market cost, the developedmethodology has a high potential to be used in the purification of Xyl.