Cultivating Pleurotus ostreatus and Pleurotus eryngii mushroom strains on agro-industrial residues in solid-state fermentation. Part II: Effect on productivity and quality of carposomes

The potential of selected Pleurotus ostreatus and P. eryngii wild-type and commercial strains to colonize and produce carposomes after solid-state fermentation of five substrates constituted of agro-residues namely wheat straw (WS), beech wood shavings (BWS), coffee residue (CR), barley and oats straw (BOS), rice bark (RB), supplemented with wheat bran was investigated. The effect of substrate composition on bioprocess feasibility was assessed for the different strains by quantitative (i.e., mushroom yield and Biological Efficiency-BE %) and carposome qualitative parameters (i.e., weight, size, colour, firmness). P. ostreatus strains produced carposomes earlier than P. eryngii ones. Early fruiting formation was promoted in WS for P. ostreatus strains, whereas for P. eryngii the lowest values of earliness were observed on BOS substrate. As for crop productivity, P. ostreatus strain AMRL 150 provided the highest BE (>70%) in all substrates except for RB, while P. ostreatus strain AMRL 144 achieved the highest yield and BE in BOS and BWS (75.30 and 64.26%, respectively). P. eryngii stains produced less number but heavier carposomes. The highest values of BE% for these strains were recorded on WS and BOS substrates. The BE was further correlated to growth parameters of fungal vegetative phase. As for mushroom colour, P. ostreatus were lighter than P. eryngii and BOS substrate promoted lightness in both strains. Firmer P. ostreatus mushrooms were produced at CR. No differences in the whiteness and firmness were detected among P. eryngii mushrooms and at any substrate used. The data included in this paper showed that Pleurotus mushrooms can be cultivated on low- or zero-value agro-industrial residues of great financial and environmental importance towards the production of value-added food products.

Automated summary

This study investigated the potential of different Pleurotus strains to colonize and produce carposomes on various agro-residue substrates. The results showed that P. ostreatus strains produced fruiting bodies earlier than P. eryngii strains, and P. ostreatus strain AMRL 150 had the highest biological efficiency in most substrates except for rice bark. P. eryngii strains produced fewer but heavier carposomes. The substrate composition also affected mushroom color and firmness.