These organisms are selleck chemicals often termed preservation recalcitrant. The need for improved preservation procedures has given rise to the field of preservation technology. However, few collections are actively involved in preservation protocol research and development.Some workers advocate the use of bead systems for the cryopreservation of bacteria. In this technique, bacteria are inoculated into a commercially available ��bead system�� which are then frozen according to the manufacturer’s instructions. Beads can then be removed and directly placed onto an appropriate nutrient media. Unused beads are then often refrozen. While the method may be very simple, repeated freeze thaw cycles can potentially compromise the genetic integrity of the organisms.5.1.

Technology TransferMany technologies used for the cryopreservation of microorganisms, have been developed in the allied fields of medicine, animal, and plant cell biotechnology and zoology. The techniques employed include vitrification cryopreservation [38, 39], encapsulation [40], and cryopreservation with a host substrate [31]. Vitrification is a technique involving the application of highly concentrated, potentially toxic solutions of cryoprotectants, and has been applied to organisms of many cell types, especially plant cells [41] and human gametes [42] often using the Crytop method [43]. Typically, the vitrification solution that surrounds the cells forms an amorphous glass upon cooling; this prevents the onset of cryoinjury. Samples are rapidly cooled in liquid nitrogen which negates the need for controlled rate cooling.

On resuscitation from the frozen state, samples are warmed and then ��liquefy.�� Care must be taken to ensure that samples do not crack which could cause physical damage to the specimen, and samples must be immediately washed to remove the toxic vitrification mixture. The technique has been applied to a range of fungi with some success [40]. Encapsulation cryopreservation is a technique where cells are embedded in calcium alginate beads prior to cryopreservation, the use of which is now well documented for microorganisms, for example, Serpula lacrymans [44] and monoxenically produced spores of the Glomeromycota [45]. The application of encapsulation has two main benefits; firstly the water content of cells can be reduced by osmotic treatment or drying which decreases the prospects of ice damage or concentration effects during the cooling stage of the cryopreservation procedure and secondly, it allows cells to be easily handled GSK-3 and manipulated by providing a suitable suspending matrix. Specimens are then rapidly ��plunge�� cooled with no need for controlled rate cooling.