The increasing growth of agro-industrial activity resulting in excessive amounts of agri-waste has led to the accumulation of a large quantity of lignocellulosic residues all over the world, in particular, deforestation initiatives for the removal of invasive trees in South Africa. These lignocellulosic residues are rich in energy resources consisting of a mixture of natural polymers based on lignin, cellulose and hemicellulose. The use of lignolytic fungi such as mushrooms in solid-state fermentation could sufficiently degrade the indigestible lignocellulosic components and add medicinal and nutritional value to otherwise unusable, high-energy waste material. The digestive type of animal for which the potential feed is developed must be identified and considered before deciding on the bioconversion method and process, since the outcomes for obtaining potentially high-quality feeds for non-ruminant and ruminant animals are different. The current study presents the data of the bioconversion of lignocellulosic substrate using solid-state fermentation with the edible and medicinal mushrooms, Ganoderma lucidum, Pleurotus ostreatus, and a possible new species, to increase digestibility and nutritional value to be applied as ruminant animal feed. The solid-state fermentation process was optimised and the resulting product analysed for the degradation of the lignocellulosic components. Results indicated that the solid-state fermentation duration and mushroom species were key components in achieving significant degradation. Data obtained after 18 weeks of degradation indicated a significant (p < 0.05) reduction in the acid detergent fibre, acid detergent lignin and neutral detergent fibre fractions of the biomass, with up to 20% reduction in indigestible components.