A MINIATURIZED METHOD FOR FREEZE-DRYING OF MICROORGANISMS IN GLASS-CAPILLARY TUBES

A successful method for freeze-drying of various sensitive bacteria an d yeasts in glass capillary tubes for long-term preservation is descri bed. The dried microbiological cells proved viable and stable after re activation. In the case of capillaries which were not sealed under vac uum, poor viabilities were demonstrated after storage at relatively hi gher temperatures (above 4 degrees C). However, only a slight drop in viability occurred during 6-12 months of storage at -80 degrees C, whe reas during storage at -30 degrees C the viability drops were relative ly higher. The capillaries sealed under vacuum proved better for stora ge at relatively higher temperatures as compared to the unsealed capil laries. For recovery, a single sealed capillary was removed without di sturbing the parallel samples. The method is first of its kind which d escribes optimal freeze-drying on miniaturized scale. For long-term st orage the pre-dried sensitive microorganisms in glass capillary tubes are ideal for cryopreservation or dry-freezing involving no controlled freezing and thawing. The dried cells in glass capillary tubes can be stored for long-terms at relatively low cost due to less storage spac e required and it is economical with respect to the transport costs. N o immediate reactivation is required before mailing. For the automatic inoculation of fermenters surface sterilized capillary tubes can be c rushed mechanically in the growth medium.