Bioprocess development for production of a process-apt xylanase with multifaceted application potential for a range of industrial processes

Abstract

Discovery of new/novel enzymes with process-apt features has been a continuous practice. A wide range pH-stable and thermostable xylanase was reported hitherto from a newly isolated fungal strain Aspergillus terreus S9, from mushroom compost. This is the first ever report where-in a pH-stable and thermostable xylanase is being reported from a strain of A. terreus. Solid state fermentation was executed on agro-industrial residues for xylanase production. Maximum xylanase production was supported by wheat bran (40 U/ml), however, substantial xylanase yield was observed on other residues like corn cob powder (38.4 U/ml), cotton cake (38 U/ml), malt (37.6 U/ml) and almond hulls (35.2 U/ml). Almond hulls are being reported for the first time as the substrate for xylanase production. Plackett–Burman design was used to earmark the most effective process variables (wheat bran, medium pH, and incubation time), and the same were optimized by design of experiments (DoE) based on response surface methodology to achieve a yield enhancement of 1.82-fold. A. terreus S9 xylanase exhibited an excellent and brisk clarification of mosambi and orange juices. DoE based optimization of process parameters (enzyme dose, treatment time and incubation temperature) resulted in 1.23-fold and 1.28-fold enhanced orange and mosambi juice clarification, respectively. Furthermore, admirable dough raising capacity and pulp brightening ability of A. terreus S9 xylanase shows its promising potential for bread making, and eco-friendly biobleaching processes, respectively. The xylanase must be in-depth investigated to decipher the molecular mechanisms of diverse applications.