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A biorefinery approach for spent coffee grounds valorization into multiple added value products, including phenols, lignin and polyhydroxybutyrate. [Display omitted] • Spent coffee grounds are upgraded into lignin, phenols, and fermentable sugars. • Deep eutectic solvents effectively allowed lignin extraction from defatted biomass. • Enzymatic saccharification of the polysaccharides was statistically-optimized. • An engineered E. coli strain converted the fermentable sugars in polyhydroxybutyrate. • All the recovered compounds can be potentially recombined as green active packaging. Coffee is one of the most popular beverages worldwide, whose consumption generates spent coffee grounds (SCGs) as one of the major by-products. A new biorefinery flowchart aimed at the integral valorization of SCGs in view of the possible implementation of a sustainable active packaging is proposed in this work. The cascade approach started with a delipidization step to get coffee oil (13.0 g/100 g SCGs). Then, a hydroalcoholic extraction followed by a treatment with a deep eutectic solvent (composed of choline chloride and lactic acid) allowed to recover low molecular weight phenolic compounds (9.6 g/100 g SCGs) and lignin (6.2 g/100 g SCGs), respectively. Both fractions were found to display promising antioxidant properties in chemical assays. The residual solid material was then submitted to saccharification through a statistical approach, enabling the optimization of the enzymatic cocktail needed to address biomass structural and compositional complexity. The process resulted in 57 % and 73 % saccharification yields for cellulose and hemicellulose respectively, corresponding to the recovery of 11.6 g of fermentable sugars per 100 g of SCGs, and led to a homogeneous residual solid (4.3 g/100 g SCGs) still endowed with antioxidant properties. Finally, the possible use of the inhibitory-free saccharification extract for the microbial production of polyhydroxybutyrate was demonstrated using a proper engineered Escherichia coli strain, achieving about 0.7 g/L of biopolymer (1.2 g/100 g SCGs). Overall, the combination of the sequential processes applied in this work allowed to recover functional compounds accounting for ca. 45 % w/w of the starting biomass, paving the way to the development of a coffee-biorefinery aimed at the designing of fully biobased materials composed of polyhydroxyalkanoates and active additives, i.e. phenols and lignin. [ABSTRACT FROM AUTHOR]