The mycelial growth speed of Pleurotus ostreatus (POS 09/100) and Lentinula edodes (LED 96/13) was evaluated in four substrates based on Simarouba amara sawdust, Anacardium giganteum sawdust, Euterpe precatoria seeds and Musa sp. AAB stems. The loss of organic matter of the substrates and the mycelial vigor of the strains studied were also evaluated. The greatest mycelial growth for P. ostreatus occurred in the substrates formulated with S. amara sawdust (29.45 cm 3 /day) and A. giganteum (27.58 cm 3 /day). The best performance for L. edodes occurred in the substrate of A. giganteum (13.22 cm 3 /day), followed by the S. amara (11.30 cm 3 /day). The most intense rates of vigor were presented in the E. precatoria substrate which was added with brans. The most significant loss of organic matter for both mushrooms occurred in the substrate formulated with a supplement of A. giganteum (54% for P. ostreatus and 61% for L. edodes). There was no mycelial growth in the formulation prepared with banana stem in both mushrooms tested.

Mycelial growth strains of POS 98/38, POS 09/100, POS 09/101, and POS 09/102 of Pleurotus ostreatus were evaluated in culture media with various compositions based on extracts of substrates formulated with sugar cane bagasse together with straws and grasses, and with or without nitrogen supplementation. The evaluation was performed during incubation regularly with a ruler graduated in millimeters until total colonization of the culture medium contained in Petri dishes. The statistical model explaining the kinetics of mycelial growth of mushroom strains of P. ostreatus as a deterministic component has an exponential Gompertz function. The results show that the culture medium with sugar cane straw and brizantha grass (supplemented) showed the highest rates of mycelial growth, regardless of strain used compared to wheat straw-based culture media with had the lowest velocities of growth, regardless of supplementation and strains studied.

We evaluated the effect of gamma irradiation doses (0, 125, 250, and 500 Gy) in control of psychrotrophic bacteria in different strains of Agaricus bisporus (ABI-07/06, ABI-05/03, and PB-1) during storage, cultivated in composts based on oat straw (Avena sativa) and Brachiaria spp. The experimental design was completely randomized in a factorial scheme 4  2  3 (irradiation doses  composts  strains), with 24 treatments, each consisting of 2 replicates, totaling 48 experimental units (samples of mushrooms). The mushrooms collected from all culture conditions were packaged in plastic polypropylene with 200 g each and subjected to Cobalt-60 irradiator, type Gammacell 220, and dose rate 0.740 kGy h -1 , according to the treatments. Subsequently, the control (nonirradiated) and other treatments were maintained at 4 ± 1°C and 90% relative humidity (RH) in a climatic chamber to perform the microbiological analysis of mushrooms on the 1st and 14th day of storage. According to the results, it was found that the highest mean colony psychotrophic count, after 14 days of storage, was observed in strain ABI-07/06 1.30 × 10 8 g -1 most probable number (MPN) in nonirradiated mushrooms, coming from Brachiaria grass-based compost, and this same strain under the same storage conditions, coming from the same type of compost that underwent a dose of 500 Gy, obtained a significant reduction in mean colonies of psychrotrophic bacteria (2.25 × 10 4 g -1 MPN). Thus, the irradiation doses tested favored reducing the number of colonies of psychrotrophic bacteria, regardless of the type of compound and strain of A. bisporus.