β-Glucosidase production by Trichoderma reesei and Thermoascus aurantiacus by solid state cultivation and application of enzymatic cocktail for saccharification of sugarcane bagasse

Abstract

For degradation of sugarcane bagasse (SCB), several enzymes are needed but β-glucosidase is rate limiting in cellulose hydrolysis. Since different microorganisms synthetize characteristic pool of enzymes, mixing extracts produced by different species may increase hydrolytic efficiency due to synergism between enzymes in cocktails. This paper reports the study of β-glucosidase production in solid state cultivation (SSC) of two filamentous fungi, thermophilic Thermoascus aurantiacus and mesophilic Trichoderma reesei, and application of the enzymatic extracts on non-pretreated SCB saccharification. Enzyme extract obtained from the thermophilic fungus presented higher β-glucosidase and FPU activities (1.8 U/mL and 10 FPU/mL) than the one from mesophilic (0.2 U/mL and 6 FPU/ mL). Optimal SCB hydrolysis was achieved when applying enzymatic cocktail composed of equal volumes of both fungal extracts (3.6 FPU/g SCB , filter paper units per gram SCB, 2.25 FPU/g SCB provided by extract from T. aurantiacus and 1.35 FPU/g SCB from T. reesei) at 65°C. The hydrolysis yield applying the enzyme cocktail, 124 mg total reducing sugars (TRS) per g SCB , was higher than any yield achieved when using the enzyme extracts separately (105 mg TRS /g SCB using 12.5 FPU per g SCB from T. aurantiacus at 65°C; 79 mg TRS /g SCB using 7.5 FPU per g SCB from T. reesei at 45°C). Therefore, the use of the cocktail (3.6 FPU/g SCB ) at 65°C released 18 and 57% more TRS respectively than when extracts from T. aurantiacus or from T. reesei were applied alone, respectively, even reducing enzyme load (FPU) by 70%, corroborating the synergistic effect when both extracts are used together.

Brewer’s spent grain biotransformation to produce lignocellulolytic enzymes and polyhydroxyalkanoates in a two-stage valorization scheme

“…This way, transportation costs could be reduced, process efficiency is improved, and the valorization of the produced leftovers in such industries is promoted. Having this in mind, the lignocellulolytic enzymes produced from the SSF of BSG could serve to hydrolyze the same leftover sustainably as previously done with other lignocellulosic wastes [30]. Then, the released fermentable sugars could be used as a source for PHA production by specific microorganisms, consequently obtaining value-added products from a lowcost substrate, achieving a two-stage valorization of the residue, and presenting an advance on the development of this bio-based industry.…”

Optimization of Endoglucanase Synthesis by Trichoderma harzianum via Taguchi Approach

“…Lignocellulolytic biomass waste is commonly used as the readily available substrate or carbon source for fungal fermentation activity. As established by the previous reports, various kinds of biomass waste such as sugarcane bagasse [12], wheat bran [12,13], corn straw [7], groundnut shell [14], and oil palm biomass [8,9,15,16] would result in enzyme production showing different enzymatic activities. The higher cellulose content in oil palm leaves (OPL) (40%) than other biomass such as trunks (34%) and empty fruit bunches (23%) [17] shows its potential to produce cellulolytic and xylanolytic enzymes.…”

Fungal cellulases: production by solid-state cultivation in packed-bed bioreactor using solid agro-industrial by-products as substrates and application for hydrolysis of sugarcane bagasse

“…At central points, 5 mL of enzyme extract were applied and hydrolysis last 4 h; levels ± 1.41 (2.2 and 7.8 mL; 1.2 and 6.8 h) and ± 1 (3.0 and 7.0 mL; 2 and 6 h) of both factors were tested. The levels of both variables were chosen based on Frassatto et al (2020), who analyzed the kinetics of enzymatic saccharification of BIN for up to 24 h. For BIN and BOU, individual (but identical) designs were run independently. The response variable was TRS released, in mg per g of BIN or of BOU.…”