Evaluation of the Viability of Pleurotus Spp. Strains After Liquid Nitrogen Cryopreservation

Abstract

Viability of 6 mushroom 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 (-196º) 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 60ºC) of the thawing system for mycelial recovery. The results showed a marked tendency toward faster mycelial recovery when samples were thawed at 30ºC, while at 60ºC 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.<br>A viabilidade de 6 cepas de fungos do gênero Pleurotus (2 de P. djamor var. djamor, 1 de P. ostreatus var. ostreatus, 2 de P. ostreatus var. columbinus e 1 de P. pulmonarius), foram avaliadas após congelamento em nitrogênio líquido (-196ºC). Foram estudados os efeitos do tempo de contato dos micélios com o criopreservativo (glicerol), antes do congelamento (por 1, 2 e 3 h), e o efeito do descongelamento sobre os mesmos, em diferentes tempos (5, 10 e 15 min) e temperaturas (30, 45 e 60ºC). Os resultados mostraram marcada tendência a uma maior recuperação dos micélios quando as amostras eram descongeladas a 30ºC, sem aparente influência dos tempos de contato com o criopreservativo e de descongelamento. A 60ºC não se observou nenhuma recuperação