Another cryo problem

[LYTTLE at BOTN.CANTERBURY.AC.NZ]

     Dear all,
     The comments over the last week or so about cryopreservation 
of microorganisms have prompted me to put my own problem before the 
net.
     I am working with four Comamonadaceae able to degrade 
in pure culture the nitrogen heterocyclic compound isoquinoline as 
sole 
carbon, nitrogen and energy source. Unfortunately they have a nasty 
tendency to lose the phenotype, especially when grown 
in a complex medium such as nutrient broth, LB medium and so forth. 
My problem is that to restore the cultures from stock at -80 C the 
organisms currently have to be grown in a complex medium or they won't 
provide a large enough inoculum for study.
      Does anyone know of a method of cryopreservation and 
restoration that may get round this? At the moment I am using the 
"Protect" bacterial preservers from Technical Service Consultants in 
the UK which use beads and a cryopreservative fluid. Any suggestions 
would be leapt upon with great glee and gusto!! Thanx in advance.

Trevor C Lyttle
Plant & Microbial Sciences Dept
University of Canterbury
Christchurch 
New Zealand