Abstract

This study proposed investigates the role of forced aeration flow and humidification pulses during solid-state fermentation (SSF) of spent coffee grounds (SCG) in optimizing fungal growth, metabolic activity, and bioactive compound release. Five fermentation conditions with aeration flows (0.5–1.5 L/min) and moisturizing pulses (30–90 mL/d) were evaluated. Chlorogenic acid (CGA), caffeic acid (CA), and quinic acid (QA) were quantified via HPLC, while antioxidant activities (AA) were assessed using ORAC, DPPH, and FRAP methods. The highest CGA yield (76.1 ± 5.2 mg/g SCGinitial) occurred between days 8–13 under 0.5LA-30LM conditions, while QA peaked at 89.5 ± 4.8 mg/g SCGinitial during days 27–30 under 0.5LA-90HM. AA reached 79,000 ?mol TEAC/100 g SCGinitial at late fermentation stages. Low aeration and controlled moisture enhanced fungal colonization, enzymatic hydrolysis, and bioactive compound recovery. These findings evidence the potential of SSF for SCG valorization and offer a framework for process optimization in industrial applications. © 2025 Elsevier Ltd