The present invention describes a bio-based process to produce high quality protein concentrate (HQPC) by converting plant derived celluloses into bioavailable protein via aerobic incubation, including the use of such HQPC so produced as a nutrient, including use as a fish meal replacement in aquaculture diets.Una composición de un concentrado de proteína que comprende proteínas de base no animal y exopolisacáridos y un bajo contenido de estaquiosa; alimento que lo contiene; método de producción; y cepas de Aureobasidium pullulans