The invention relates to a method for producing a
solid transformation product of a substrate comprising the following steps: • preparing a substrate of
biomass comprising carbohydrates and proteinaceous matter that originates from
soya bean,
rape seed, or mixtures thereof, optionally in further mixture with carbohydrates and proteinaceous matter originating from fava beans, peas,
sunflower seeds, lupine, cereals, and / or grasses, • mixing said substrate with a live
microorganism or a combination of live microorganisms, which live
microorganism or mixture of live microorganisms is not live
yeast, and adding water in an amount which provides an initial incubation mixture having a
water content from 30 to 70% by weight, and a ratio of wet
bulk density to dry
bulk density from 0.60 to 1.45 in the resulting mixture; • incubating said initial incubation mixture for 1-240 hours at a temperature of 15-70° C.; and thereafter recovering wet
solid transformation product from the incubation mixture; further comprising that the incubating step is performed as a continuous plug-flow process in a vertical, non-agitated incubation tank with inlet means for said mixture and additives and outlet means for said
solid transformation product.