Parthenium hysterophorus Weed as a Novel Substrate for β-Glucosidase Production by Penicillium citrinum NAF5: Application of the Crude Extract to Biomass Saccharification

Fungal cellulases are well-studied enzymes with various industrial applications. The key goal of this work was to evaluate the possibility of non-conventional P. hysterophorus weed biomass valorization by using it to produce β-glucosidases using the fungus P. citrinum NAF5. For a comparative analysis, three independent variables selected from the ‘one variable at a time’ approach were subjected to response surface methodology. To assess the interacting outcome of the significant factors, the central composite design (CCD) was used. The CCD was applied by considering carbon source (lactose % w/v), nitrogen source (peptone % w/v), and pH as the model factors for the present analysis. The maximum β-glucosidase production (2.48 U/ml) was obtained with lactose 1.50% (w/v), peptone 1.50% (w/v), and pH 6. The crude enzyme preparations from P. citrinum NAF5 were used to saccharify sodium carbonate (1% w/v) pretreated P. hysterophorus biomass. After 7 h enzymatic hydrolysis of sodium carbonate pretreated P. hysterophorus biomass, a maximum release of reducing sugars of 92.48 mg/g substrate was observed, which is 3.3-fold higher than that of untreated biomass (28.02 mg/g substrate), indicating that P. citrinum NAF5 has the potential to produce the crude enzyme for lignocellulosic biomass hydrolysis.