Screening strains of genus Pleurotus for biomass production in solid state fermentation of agricultural residues

The ability of several strains belonging to Pleurotus ostreatus and P. eryngii mushroom genera to grow on various agricultural residues was examined and their mycelium growth rates and biomass production (estimated as glucosamine content) were compared. Four P. ostreatus (AMRL 137, 144, 147, 150) and four P. eryngii (AMRL 160, 163, 166, 173-6) strains were cultivated on wheat, barley and oat straw, oak- and beech-wood sawdust, cotton and coffee residues, corn-cobs, rice bark, olive cake supplemented with wheat bran on a final C/N 20-30. Colonization rate measurements of mycelium demonstrated faster colonization on wheat, oak, barley and oat, corn-cobs and rice with values of ~1.5 mm/day, yet the faster colonizers were P. ostreatus 144, 150 and P. eryngii 166, 173-6. Glucosamine content was similar for P. ostreatus and P. eryngii strains and the most pronouncing substrates for more biomass production were barley and oat straw, beech-wood sawdust, cotton and coffee residues, corn-cobs (max 170 mg/g d.w.). However, in most of the cases, glucosamine content was opposite to mycelial growth rate, as strains with high colonization rates produced the least biomass. These results are evaluated in the view of bio-converting agricultural wastes into mushrooms, an added value food with medicinal properties.