Tratamentos térmicos do calxisto para uso como camada de cobertura no cultivo de Agaricus brasiliensis

The preservation of Agaricus blazei is generally done by mycelial subculturing, but this technique may cause genetic degenerations. Despite this, there is not an efficient protocol established to preserve this fungus and cryopreservation could be an alternative. This study aimed to evaluate two freezing protocols for cryopreservation at -80°C of A. blazei strains. Five fungus strains grown on rice grains with husk and were transferred to glycerol (10%) in cryovials. Next, the cryovials were submitted to two freezing temperature protocols: (1) cryopreservation starting at 25°C, then at 8°C for 30 min and kept at -80°C;(2) cryopreservation starting at 25°C, then 8°C for 30 min, -196°C for 15 min and kept at -80°C. After 1 year of cryopreservation, the cryovials were thawed in a water bath at 30°C for 15 min and transferred to malt extract agar medium. It was concluded that the one-year cryopreservation process of A. blazei, grown on rice grains and cryopreserved at -80°C in glycerol 10%, is viable. The slow freezing, from 8 to -80°C, is effective whereas the fast freezing, from 8 to -196°C and then to -80°C, is ineffective. The different genetic characteristics among the strains of this fungus do not interfere in the cryopreservation process.

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