One-pot conversion of industrial hemp residue into fermentable feedstocks using green catalyst and enzyme cocktails generated by solid-state fermentation

Abstract

This study isolated fascinating novel fungal consortium from pomelo peel (PP) to discover its potential for on-site production of lignocellulose degrading enzymes through solid-state fermentation (SSF). SSF strategy was developed to use low and high recalcitrant substrates including PP and industrial hemp residue (IHR), respectively. The result revealed that SSF using a mixture of these substrates was significantly enhanced as compared with the corresponding individual substrate. IHR was pretreated with autohydrolysis, thermal hydrolysis, and thermochemical hydrolysis. A green and sustainable catalyst, oxalic acid, was employed to further optimize the thermochemical pretreatment of IHR. Pretreatment with 3% (w/v) oxalic acid resulted the highest sugar which is 8.3 and 3.24 folds compared to autohydrolysis and thermal hydrolysis, respectively. Finally, a novel approach dubbed one-pot pretreatment and saccharification was implemented using IHR treated with 2% oxalic acid and enzymes generated by SSF of mixed substrates. This strategy resulted the highest sugar production of 39.49 g/L. The current study can be considered as a proof-of-concept for sustainable and economic production of bio-based products from waste biomass resources.