The macroalgae aquaculture industry has grown up in the last years, and new applications for macroalgae should be considered. In this work, sequential biological treatments as solid-state fermentation (SSF) by Aspergillus ibericus and enzymatic hydrolysis (EH) were applied to washed and unwashed Ulva rigida. SSF of unwashed macroalgae showed higher xylanase (359.8 U/g), cellulase (73.07 U/g) and beta-glucosidase (14.9 U/g) activities per dry mass of macroalgae. After SSF, two strategies to carry out EH were assayed. The best process was SSF followed by EH by simply adding a buffer. The non-starch polysaccharides content was reduced by 93.2%, achieving a glucan conversion of 98%. In addition, the antioxidant activity was improved 2.8-fold and the protein concentration of macroalgae extracts increased from 16.9% to 29.8% (w/w). These biological treatments allowed to increase macroalgae value as feedstuff with potential for use in aquafeeds.