Characterization of multiple xylanase forms from Aspergillus tamarii resistant to phenolic compounds

Aspergillus tamarii was cultivated in different textile wastes. Xylanases with high levels of enzymatic activity were produced after two days cultivation, with constant production for up to seven days. Two xylanases, namely Xyl-1 and Xyl-2, with molecular masses of 35.5 and 22 kDa, respectively, were isolated from the crude extract and purified by ultrafiltration and gel filtration chromatography. Xyl-1 and Xyl-2 were more active at pH 6.0, and 60 degrees C and 40 degrees C, respectively. The respective K-M and V-max values on soluble oat spelt xylan were 4.30 mg. mL(-1) and 0.249 IU. mL(-1) (Xyl-1) and 18.92 mg. mL(-1) and 1.103 IU. mL(-1). s(-1) (Xyl-2). Dynamic light scattering (DLS) was used to evaluate purification steps, effective in assessing the degree of purity of the samples, the presence of aggregations and the size of the enzymes. Tween-80 at 0.1% was an efficient dispersing agent for avoiding aggregation of proteins and did not influence enzyme activity. Purified and partially purified xylanases were activated with auto-hydrolysis liquor from corncob and with ferulic acid, a phenolic compound derived from lignocellulosic biomass. These findings of this study indicate that A. tamarii produces multiple forms of xylanases with considerable potential in different biotechnological applications.