Forty years in liquid nitrogen: an investigation into cryobank management and culture viability

Effective and accurate resource management is an essential aspect to tissue banks and culture collections, in particular for cryopreserved specimens. The Culture Collection for Algae and Protozoa (CCAP), based in Scotland, has been maintaining and expanding its collection of cryopreserved strains since the late 1970’s, and now houses approximately 800 strains of microalgae and protozoa in liquid nitrogen. Over the past 40 years, methods of record keeping have progressed from paper-based card-index inventories to computer databases, just as the collection has been moved between storage vessels in order to preserve the collection to accommodate for improving technologies. The work presented here examines the common errors and implications of maintaining a database that is concordant with the collection’s status. An alternative barcoding system is tested to investigate the functionality of the system in terms of ease of use and practicality, and how the system can help to alleviate common database errors discussed. The viabilities of old cultures from a variety of microalgae strains were also tested to detect any loss of viability after 20-40 years in storage for samples that have been consistently stored at ultra-low temperatures and those that underwent a short, accidental, rewarming 10 years ago.