Structural and Functional Characterisation of Xylanase Purified from Penicillium Chrysogenum Produced in Response to Raw Agricultural Waste

Commercial interest in plant cell wall degrading enzymes (PCWDE) is motivated by their potential for energy or bioproduct generation that reduced dependency on non-renewable (fossil-derived) feedstock. Therefore, underlying work analysed the Penicillium chrysogenum isolate for PCWDE production by employing different biomass as a carbon source. Among the produced enzymes, three xylanase isoforms were observed in the culture filtrate containing sugarcane bagasse. Xylanase (PcX1) presenting 35 kDa molecular mass was purified by gel filtration and anion exchange chromatography. Unfolding was probed and analysed using fluorescence, circular dichroism and enzyme assay methods. Secondary structure contents were estimated by circular dichroism 45% alpha-helix and 10% beta-sheet, consistent with the 3D structure predicted by homology. PcX1 optimally active at pH 5.0 and 30 degrees C, presenting t(1/2) 19 h at 30 degrees C and 6 h at 40 degrees C. Thermodynamic parameters/melting temperature 51.4 degrees C confirmed the PcX1 stability at pH 5.0. PcXI have a higher affinity for oat spelt xylan, K-M 41.2 mg.mL(-1) in comparison to birchwood xylan K-M 29.86 mg.mL(-1) activity was inhibited by Cu+2 and activated by Zn+2. PcXI exhibited significant tolerance for vanillin, trans-ferulic acid, rho-coumaric acid, syringaldehyde and 4-hydroxybenzoic acid, activity slightly inhibited (17%) by gallic and tannic acid. (C) 2019 Elsevier B.V. All rights reserved.