[Microbiology] Transformannt Yeast Cell Bank

[Mahmoud Ibrahim]

Hi,

I have a recombinant yeast strain on a petri dish that I wish to preserve. Does anyone have a protocol for performing a master cell bank for transformant yeast so that the viability of the cells and the stability of thhe transformation is maintained for a long time? 

I also have another question: if such a strain was kept on an agar plate for more than three months, will it loose its viability and will the transformation become unstable? 

Thanks a lot for your help in advance!

Best Regards,
Mahmoud Ibrahim