Evaluation of the viability of pleurotus spp. strains after liquid nitrogen cryopreservation

RESUMO

Viability of 6 mushrooms strains of the Pleurotus genus (2 from P. djamor var. djamor, 1 from P. ostreatus var. ostreatus, 2 from P. ostreatus var. columbinus and 1 from P. pulmonarius) after liquid nitrogen cryopreservation (-196§) was evaluated. The contact time for the mycelia of these strains with the cryoprotectant (glycerol) was studied 1,2 and 3 hours before freezing. We also tested the effect of different times (5, 10 and 15 minutes) and temperatures (30, 45 and 60§C) of the thawing system for mycelial recovery. The results showed a marked tendency toward faster mycelial recovery when samples were thawed at 30§C, while at 60§C no recovery was observed. A change in thawing and contact times with the cryoprotectant did not affect the results significantly, as the thawing temperature and strain employed affected