Preservation of Mycoplasma strains by freezing in liquid nitrogen and by lyophilization with sucrose

Procedures for maintaining Mycoplasma strains are described. Liquid nitrogen storage provided an adequate means for keeping stock cultures stable. Over 74 strains of approximately 26 species have been preserved in this way, some for as long as 9 years. Mycoplasma strains can also be recovered satisfactorily from the freeze-dried state when the procedure described includes the use of 12% (v/v) sucrose as an additive. Fifteen strains representing 12 or more species were subjected to a freeze-drying program with and without sucrose added to concentrated cell suspensions in growth medium. Cell counts indicate improved survival with sucrose.