Fermentation of cellobiose to ethanol by industrial Saccharomyces strains carrying the β-glucosidase gene (BGL1) from Saccharomycopsis fibuligera

► Constitutive actin promoter drives efficient expression of BGL1 in Saccharomyces. ► Saccharomyces genetic background affects heterologous β-glucosidase synthesis yields. ► The efficiency to synthesize Bgl1 affects ethanol yields from cellobiose fermentation. ► Ethanol production depends also on the genetic background of the host strain.