Synergistic production of highly active enzymatic cocktails from lignocellulosic palm wastes by sequential solid state-submerged fermentation and co-cultivation of different filamentous fungi

Lignocellulolytic enzymes were produced from industrial crop wastes, palm empty fruit bunches (EFB), through various fermentation modes and co-cultivation of different filamentous fungi. Among the fermentation modes and fungi tested, Aspergillus tubingensis TSIP9 produced enzymatic cocktails with the highest cellulase (89.6 +/- 5.7 U/g-EFB) and xylanase (196.8 +/- 3.6 U/g-EFB) activities through sequential solid-state and submerged fermentation (SoSF-SmF), while Trichoderma reesei QM 9414 showed the highest beta-glucosidase (47.9 +/- 0.9 U/g-EFB) activity through SmF. Interestingly, their co-cultivation in sequential SoSF-SmF significantly improved overall enzyme production possibly due to synergism of the enzymes produced by both strains and combined advantages of SoSF and SmF. After optimization and scale-up in bioreactor with helical impeller, the cellulase, xylanase and beta-glucosidase activities were enhanced up to 374.8 +/- 4.23 U/g-EFB (4.2 folds), 623.7 +/- 4.59 U/g-EFB (3.2 folds) and 161.87 +/- 1.74 U/g-EFB (3.4 folds), respectively. These enzymes are highly active and stable at pH 5-6 and temperature of 50-60 degrees C. These strategies could be viable options for effective and low-cost production of lignocellulolytic enzymes and further application in bioproduction and biorefinery.

Automated summary

In this study, lignocellulolytic enzymes were efficiently produced from industrial crop wastes, specifically palm empty fruit bunches (EFB), using different fermentation modes and co-cultivation of filamentous fungi. Aspergillus tubingensis TSIP9 showed the highest cellulase and xylanase activities, while Trichoderma reesei QM9414 exhibited the highest beta-glucosidase activity. Co-cultivation significantly improved overall enzyme production, leading to enhanced activities of cellulase, xylanase, and beta-glucosidase after optimization and scaling up in a bioreactor with a helical impeller. These enzymes are highly active and stable under specific pH and temperature conditions, making them promising for low-cost production and biorefinery applications.