Optimization of Fermentative Parameters for Hyperproduction of Protease from Aspergillus viridi using Lignocellulosic Byproducts as Sole Substrate

In this study various Aspergillus strains were explored for the production of protease using variety of agricultural byproducts as substrate. Aspergillus viridi was found to be the best among the selected strains with production of 83.0 U/mL of protease when grown on casein broth medium. Various agricultural byproducts were utilized for the growth of A. viridi and for the maximum protease production. Optimal production of enzyme 172.6 U/mL was recorded when PDB medium was supplemented with 3% banana peels powder as compared to 90.7, 84.7, 71.5, 68.7 and 47 U/mL when PDB medium was supplemented with pomegranate peels (3%), mustard oil cake (3%), arabic gum sawdust (2%), linseed oil cake (2%) and rosewood sawdust (3%) respectively. A. viridi could produce 172.6 U/mL when grown on 3% banana peels as sole substrate for growth. The protease production was increased with optimization of substrate water ratio (1:3), incubation time (72 h), inoculum size (2 mL), pH (8) and temperature (35 °C) from 172.6 to 178.1, 180.2, 182.9, 188.7 and 193.1 U/mL. Under optimal conditions, A. viridi produced 202.8 U/mL using agricultural byproducts as sole substrate. The strong potential of protease to remove hair from skin makes this enzyme a suitable candidate for its utilization in leather industry.