Mushroom mycelium as a sustainable high-protein food source: effects of submerged fermentation conditions on mycoprotein production and mycelial morphology

Abstract

Harnessing edible fungal mycelium as a source of health-promoting food presents a transformative pathway for enhancing global food security and meeting the nutritional demands of the world's growing population in the 21st century. The mycoprotein from fungal mycelium also serves as a sustainable alternative to resource-intensive animal-sourced protein. This study investigated how submerged fermentation influences the mycelial morphology and mycoprotein production of the edible fungus Pleurotus ostreatus. Key parameters including inoculum fragmentation, types of carbon sources, carbon-to-nitrogen (C/N) and carbon-to-phosphorus (C/P) ratios, and agitation rate were systematically evaluated. Principal component analysis (PCA) was employed to identify the most influential parameters and elucidate their correlations with production metrics. Controlled inoculum fragmentation, inoculum density and agitation were found to be crucial for achieving uniformity in pelletized mycelium and improving productivity. Protein content and production increased with a decreasing C/N ratio, achieving a maximum of 39.7% (of dry biomass) and 3.89 g L⁻¹, respectively, while they were not significantly influenced by the C/P ratio. Oleic acid, a plant-based fatty acid, was demonstrated for the first time as a sole non-sugar carbon source for P. ostreatus cultivation, achieving a biomass yield comparable to that of glucose. Maximum biomass production (12.9 g L⁻¹) and productivity (1.61 g L⁻¹ day⁻¹) were attained under optimized inoculum fragmentation level, an inoculum density of 40 mg L⁻¹, an agitation rate of 150 rpm, a carbon loading of 3.6 g L⁻¹, a C/N ratio of 2.6 and a C/P ratio of 52.9. These findings provide valuable insights into establishing an efficient and sustainable biorefinery for mycelium-based foods.