Integrated rheological, morphological and biochemical approaches to investigate performances of an enzymatic secretome from Talaromyces sp. BRG1 to degrade pretreated sugarcane bagasse and paper-pulp

Exploring cellulolytic secretome is a promising strategy to produce a cost-effective enzyme preparation for biorefinery of lignocellulosic waste. In this study, a fungal secretome from Talaromyces sp. BRG1 was produced with pretreated sugarcane bagasse (SCB) as the inductive substrate. Hydrolysis capacity of BRG1 secretome and commercial enzyme Cellic® Ctec2 were compared on SCB and then applied to paper pulp (PP). Normalised activity profile of cocktails based on filter paper unit activity (FPU) indicated that BRG1 secretome exhibited a higher endo-glucanase (CMCU, 4.4) and endo-xylanase activities (EnXU, 1.6) but lower avicelase (AVCU, /8.4) and cellobiase (CBU, /3.4) activities. Lignocellulolytic cocktails were examined on SCB as reference before applied on PP at 3% w/v solid loading in batch mode for 24 h. For both substrates and enzyme loading ratio (0.3 and 3.0 FPU/g cellulose), the glucose yield by BRG1 secretome was 2 times higher than Cellic® Ctec2. In-situ viscometry confirmed the quicker liquefaction efficiency of secretome over Ctec2. At 0.3 FPU/g cellulose, the suspension viscosity of PP collapsed completely after 12 h with BRG1 secretome whereas a limited reduction to 44% was observed with Ctec2. Ex-situ particle size distribution revealed a stronger reduction of coarse and fine particles with BRG1 secretome compared to Ctec2.