Optimization of Phenolic Compounds Extraction and Enzymatic Hydrolysis of Spent Coffee Grounds (SCG)

Spent coffee grounds (SCG) represent a valuable byproduct, naturally rich in lipids, polyphenols, and fermentable sugars. This study presents an integrated valorization approach, starting with lipid extraction and characterization of the resulting defatted matrix. It then focuses on the extraction of phenolic acids—particularly chlorogenic acid (5-CQA) and its derivatives—as well as non-phenolic compounds, with a specific focus on caffeine—was optimized by evaluating different ethanol–water ratios and temperatures, with the aim of identifying the most effective extraction conditions. Finally, enzymatic hydrolysis was performed using cellulolytic and accessory enzymes to improve fermentable sugars recovery. The results demonstrate the efficiency of this fractionation strategy and confirm the potential of SCG as a sustainable feedstock for green biorefinery applications.