The present study aimed to evaluate the influence of solid-state fermentation on the antioxidant activity of mangaba seeds substrate (Hancornia speciosa Gomes). Solid-state fermentation (SSF) was performed at 40 °C in an incubator for 18 h using a bacterium of the Bacillaceae family. After fermentation, the substrate was lyophilized. Extraction of the bioactive compounds from the substrate was performed using ultrasound and ethanol as solvent at the ratio of 1:10 (m/m). Total phenols analysis were carried out using the Folin-Ciocalteu method and the DPPH radical (2,2-diphenyl-1-picrylhydrazyl) inhibition capacity. Total phenols concentration was 467.82 ± 32.14 mg GAE/100 g sample and a 50% reduction capacity of DPPH (IC50 ) obtained was 879.7 ± 13.2 µg mL-1.