How can bacteria and fungus be preserved in cryovials at-80degrees?

If you're looking to store E.coli long term at -80, then you can make glycerol stocks of your cultures.

You grow an overnight culture of your bacteria in an appropriate medium and then dilute a sample of the culture 50/50 with sterile 50% glycerol. Vortex and flash freeze the stock on dry ice and store at -80C.

To revive the culture, scrape a sterile toothpick through the frozen sample and then streak out an agar plate with appropriate selection antibiotic.

For fungus here is a reference from

Microbiologia. 1993 Apr;9(1):28-33
Pubmed shortcut

Storage of stock cultures of filamentous fungi at -80 degrees C: effects of different freezing-thawing methods.
Juarros E, Tortajada C, García MD, Uruburu F.

Departamento de Microbiología, Facultad de Biológicas, Universitat de Valencia, Spain.

Freezing and storage at -80 degrees C has been applied to the preservation of nonsporulated filamentous fungi Phytophthora, Pythium, Sclerotinia and Rhizoctonia, and the results are presented. We had tested different methods of freezing and thawing, finding that the best results were obtained pre-cooling at 4 degrees C during 1 hour followed by freezing at -80 degrees C. The best thawing method was achieved at 37 degrees C. The technique was found to be simple and reliable for the culture collections labours of fungi maintenance.

PMID: 8397963

A more rececnt reference for fungus would be

http://www.springerlink.com/content/37036wye5yxa1318/

A new method for the preservation of fungus stock cultures by deep-freezing.

Accession number;02A0787777

Title;A new method for the preservation of fungus stock cultures by deep-freezing.

Author;KITAMOTO Y(Tottori Univ., Tottori, Jpn) SUZUKI A(Chiba Univ., Chiba, Jpn) SHIMADA S(Hokuto Corp., Nagano, Jpn) YAMANAKA K(Hokuto Corp., Nagano, Jpn)
Journal Title;Mycoscience
Journal Code:X0034B
ISSN:1340-3540
VOL.43;NO.2;PAGE.143-149(2002)
Figure&Table&Reference;FIG.1, TBL.5, REF.17
Pub. Country;Japan
Language;English


Abstract;Recovery of 66 fungus stock cultures including Oomycota, Zygomycota, Ascomycota, Basidiomycota, and mitosporic mycetes were examined after cryopreservation. Almost all the stock cultures remained viable when the mycelia that had grown over the sawdust medium containing 10% glycerol as the cryoprotectant (65% moisture content, W/W) were frozen rapidly at -85.DEG.C. and then allow to thaw naturally at room temperature. Test stock cultures were preserved for more than 10 years by this preservation method without any programmed precooling and rapid thawing for their cryopreservation. Most of the test fungi could survive for 5 years in medium containing 10% glycerol even after alternate freezing and thawing at intervals of 6 months. When a strain of Flammulina velutipes was tested for mycelial growth rate and productivity of fruit-bodies after cryopreservation for 3 years, the fungus reproduced with its initial capability. These results demonstrate that the sawdust-freezing method using a cryoprotectant is expected to be a reliable and easy preservation method for fungus stock cultures. (author abst.)