PRESERVATION OF CHLOROFLEXUS BY DEEP-FREEZING AND LIQUID-DRYING METHODS

Long-term preservation methods for Chloroflexus are described. All tes ted strains of Chloroflexus aurantiacus and Chloroflexus aggregans wer e successfully preserved and reactivated within a relatively short tim e with full pigmentation, indicating that their viability, stability a nd ability to grow photoautotrophically were not affected. The culture s were preserved in liquid nitrogen under anaerobic conditions using 5 % dimethylsulfoxide, 5% methanol or 10% glycerol as cryoprotectants. F or easy storage and transport, the cultures were successfully dried in small glass ampoules directly from the liquid phase, without involvin g freezing under semiaerobic conditions. All tested cultures showed go od survival rates after drying and on long-term storage. Cryopreservat ion, liquid-drying and reactivation in the absence of oxygen proved ve ry effective, as, presumably, they reduce the chance of producing free radicals, which are considered as damaging to living cells. (C) 1998 Elsevier Science B.V.