The breakdown of plant biomass having a high lignin content using the Pleurotus ostreatus fungus allows the conversion of 36-42% of said biomass into edible mushrooms of high nutritional value, the remaining 58-64% being a plant biomass massively invaded by the structures of the fungus and in which the lignin has broken down by 90-99%. This natural process has been optimised by means of potentiation of the inoculum, stimulation of the degradative enzymes and control of factors such as oxygenation, moisture and light, thereby facilitating the colonisation by the fungus and limiting the conditions necessary for contamination. This optimisation dispenses with the use of growth promoters, antibiotics or complex methods, allowing the production of mushrooms suitable for human consumption that include a high protein index (25-34% of the dry weight, 18-23% animal protein and 7-11% vegetable) and an enriched compost suitable for use in farming. This process, which is 100% organic, provides an environmentally friendly and effective solution to the problem of hard-to-break-down agroindustrial waste, such as, for example, waste from the African oil palm (Elaeis guineensis) sector.La degradación de biomasa vegetal con alto contenido de lignina a través del hongo Pleurotus ostreatus, permite la conversión del 36-42% de dicha biomasa en setas comestibles de alto valor nutricio, el restante 58-64% es una biomasa vegetal invadida masivamente por las estructuras del hongo y cuya lignina ha sido degradada en un 90-99%. Este proceso natural se ha optimizado a través de la potenciación del inoculo, la estimulación de las enzimas degradadoras y el control de factores como la oxigenación, humedad y la luz, facilitando así la colonización por parte del hongo y limitando las condiciones necesarias para una contaminación. Mediante dicha optimización no es necesario recurrir a promotores de crecimiento, antibióticos o métodos complejos, lo que permite dar lugar a setas aptas para el consumo
