Investigation of Ultralow Temperature for Fungal Cultures III. Viability and Growth Rate of Mycelial Cultures Following Cryogenic Storage

SUMMARY

One hundred and two fungal strains remained viable by cryogenic preservation for nine years. Two strains survived for only six years. Of the two suspending media used, dimethyl sulfoxide was significantly better than glycerol as a cryoprotectant for eight strains. During storage, seven viability checks were performed. Variability was examined in relation to storage time, frozen-thawed cultures vs. first subcultures, mycelial plugs (discs), and vials. Variation in radial growth of colonies was a function of innate properties of an organism, and there was no evidence that variation was influenced by cryogenic conditions (freezing and storage). The proposed method of preservation was demonstrated to be suitable for long- term conservation of these strains and is presumably applicable to other mycelial cultures.