Preservation Techniques for Industrially Important Microorganisms

Question: What are the preservation techniques for maintenance of the industrially important microorganisms ?

Answer:

For industrially important microorganisms, maintenance of the desirable strains is very much important. Preservation of these strains ensure optimal long time viability, genetic stability and purity of the microorganism. Several  preservation methods have been developed and they are as follows,

1. Periodic Transfer to Fresh Media: Strains can be maintained by periodically preparing a fresh subculture from previous stock culture. The culture medium, the storage temperature and the time interval at which the transfer undergoes , varies depending upon the species. The temperature and the growth medium should  support a slow growth rather than a rapid one in order to make the time interval between transfers as long as possible.

Artificial Transformation and the role of calcium chloride-heat shock treatment

Question: What are the roles of CaCl2  and heat shock in artificial transformation ? 

Answer: 

Artificial transformation is accomplished by inducing competence in cells by using chemicals or electroporation. The most common method of making competent cells is CalCl2 and heat shock treatment. In this technique an early log phase culture is centrifuges and re-suspended in a cold, hypo-tonic CalCl2 solution, and after that DNA is added to these cells, followed by a brief heat shock, which allows transportation of the DNA into the cell. The roles that CalCl2 and heat shock play in accomplishing this, are as follows-