A method for manufacturing a protein-rich biomass comprising at least one fermented substrate and at least one strain of an edible filamentous fungus, said method comprising the steps of: a) providing at least one substrate to be fermented, said substrate(s) having total solid loading of from 51% to 85%; wherein said at least one substrate is selected from a group consisting of root vegetables and residues and derivatives thereof, grains and residues and derivatives thereof, legumes and residues and derivatives thereof, marine organisms and residues and derivatives thereof, potato protein liquor (PPL), distillers dried grain with solubles (DDGS) as well as precursors and residue thereof, and mixtures thereof; b) inoculating said at least one substrate with at least one strain of an edible filamentous fungus thus obtaining at least one inoculated substrate; c) setting a set of conditions, wherein said set of conditions comprises humidity level of from 20% to 100%, flow rate of a second gaseous fluid of from 0.25 to 4 vvm, temperature of from 30°C to 45°C, light intensity of from 4.0 x 10 14 to 5.0 x 10 14 Hz and pH of from 3 to 7; d) fermenting said at least one inoculated substrate at said set of conditions while continuously monitoring at least one parameter, thus obtaining a protein-rich biomass comprising at least one fermented substrate and at least one strain of an edible filamentous fungus; wherein said at least one strain of an edible filamentous fungus is selected from a group consisting of Rhizopus spp., Aspergillus spp., Neurospora spp., Monascus spp. and Rhizomucor spp., and wherein said set of conditions is amended as a function of said at least one parameter. a) providing at least one substrate to be fermented, said substrate(s) having total solid loading of from 51% to 85%; wherein said at least one substrate is selected from a group consisting of root vegetables and residues and derivatives thereof, grains and residues and derivatives thereof, legumes and residues and derivatives thereof, marine organisms and residues and derivatives thereof, potato protein liquor (PPL), distillers dried grain with solubles (DDGS) as well as precursors and residue thereof, and mixtures thereof; b) inoculating said at least one substrate with at least one strain of an edible filamentous fungus thus obtaining at least one inoculated substrate; c) setting a set of conditions, wherein said set of conditions comprises humidity level of from 20% to 100%, flow rate of a second gaseous fluid of from 0.25 to 4 vvm, temperature of from 30°C to 45°C, light intensity of from 4.0 x 10 14 to 5.0 x 10 14 Hz and pH of from 3 to 7; d) fermenting said at least one inoculated substrate at said set of conditions while continuously monitoring at least one parameter, thus obtaining a protein-rich biomass comprising at least one fermented substrate and at least one strain of an edible filamentous fungus; wherein said at least one strain of an edible filamentous fungus is selected from a group consisting of Rhizopus spp., Aspergillus spp., Neurospora spp., Monascus spp. and Rhizomucor spp., and wherein said set of conditions is amended as a function of said at least one parameter. <EOS>