Viability of Agaricus blazei after long-term cryopreservation

Agaricus blazei is a basidiomycete of medicinal and gastronomic importance, but few publications have appeared on preservation. We have evaluated cryopreservation at -70A degrees C using different cryoprotectants and freezing protocols. Malt extract agar disks containing grown mycelia were transferred to cryotubes containing different cryoprotective solutions. Freezing protocols were from 25A degrees C to: (1) 4A degrees C for 30 min and then to -70A degrees C or (2) directly to -70A degrees C. The results demonstrate that it is the cryoprotective agent-and not the freezing protocol-which was the most important variable for maintaining mycelial viability after cryopreservation. Long-term cryopreservation (4 years) was effective when saccharose or glucose was used as cryoprotectant regardless of the freezing protocol, dimethyl sulfoxide was effective when a slow freezing protocol was used, and glycerol, polyethylene glycol, and malt extract were ineffective as cryoprotectants regardless of the freezing protocol. All of the cryoprotectants tested were effective for the short-term cryopreservation (1 year) of , with the exception of malt extract.