Heterologous β-glucosidase in a fungal cellulase system: Comparison of different methods for development of multienzyme cocktails

•Aspergillus niger β-glucosidase (AnBGL) boosts hydrolytic performance of cellulases.•Cofermentation of cellulase and AnBGL-expressing Penicillium strains was carried out.•113% increase in glucose yield in Avicel hydrolysis was achieved using this approach.•Cofermentation of two strains of the same fungus is promising.

Three approaches for enrichment of Penicillium verruculosum cellulase multienzyme cocktails with a heterologously expressed Aspergillus niger β-glucosidase (AnBGL) for boosting the hydrolytic performance of cellulases were tested. The best boosting effects (73–113%) on glucose yield in 72-h hydrolysis of milled aspen wood and Avicel provided the enzyme preparation obtained by cofermentation of two P. verruculosum strains, one of which was a basic high-cellulase strain, while the other was capable to produce the heterologously expressed AnBGL (up to 80% of the total protein when used in a separate fermentation). Two other approaches, based on individual fermentations of P. verruculosum strains, carrying the heterologous AnBGL under the control of either a strong cbh1 gene promoter or a weaker hist4 gene promoter, also provided notable boosting effects, although they were less pronounced than in the first mentioned case.

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