Lactoserum as a moistening medium and crude inducer for fungal cellulase and hemicellulase induction through solid-state fermentation of apple pomace

Abstract

Abstract Objectives The potential of lactoserum as a crude inducer and moistening medium for fungal cellulase and hemicellulase induction was tested through solid-state fermentation. Methodology Solid-state fermentation was conducted in Erlenmeyer flasks and plastic trays using apple pomace (AP) as solid substrate by Aspergillus niger NRRL 567 and A. niger NRRL 2001. Results Solid-state tray fermentation resulted in cellulase activities (IU g−1 dry weight basis) of 383.7 ± 17.9, 425.3 ± 21.3, 336.1 ± 16.2 and 4868 ± 39.8, respectively for FPase (filter paper cellulase), CMCase (carboxymethyl cellulase), BGL (β-glucosidase) and xylanase using A. niger NRRL 567. Similarly, A. niger NRRL 2001 resulted in enzyme activities (IU g−1) of 401 ± 23.8, 544.7 ± 24.5, 285.4 ± 11.7 and 4580.7 ± 34.5, respectively for FPase, CMCase, BGL and xylanase. The enzyme loading of FPase 50 IU g−1 substrate in the hydrolysis of AP resulted in (g kg−1): 509.3 ± 22.9 total sugar (48 h), 109.3 ± 5.7 reducing sugar (48 h), 16.1 ± 0.8 glucose (60 h) and 10.4 ± 2.0 xylose, respectively whereas hydrolysis of BSG resulted in (g kg−1): 375.7 ± 16.2 total sugars (36 h), 114.6 ± 4.0 reducing sugar (60 h), 18.1 ± 0.9 glucose (60 h) and 19.8 ± 2.0 xylose (48 h), respectively. Conclusions This study demonstrated the potential of SSF as a simple and cheap technology for higher cellulase and hemicellulase production using negative cost AP waste which could eventually help to utilize abundant lignocellulosic biomass for production of biofuels and other value-added products.