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Read the following statements regarding preservation of microorganisms
(A) . For preservation of microorganisms cryopreservation and lyophilization are highly utilized for culture collections and
industry.
(B) . In cryopreservation and lyophilization, cells are subjected to cryogenic temperatures which promote ice crystal formation
in the suspension medium and within the cell interior, and resulting osmotic imbalance induces biophysical and biochemical
changes and causes cryo-injuries and cell death, which can be prevented by use of cryo or lyo protectants
(C) . Propanol (10-15%) and proline (5%) are frequently used in cryopreservation of microorganisms, and they do not
penetrate cell
(D) . Preservation of cells at -20 °C is recommended for long-term preservation and it is considered ideal because the
chances of DNA mutations are almost zero at that temperature.
(E) . Lyophilization is the preferred long-term preservation method in most microbial resource centers due to the low cost of
maintenance and ease of transportation of lyophilized cultures.
Choose the correct answer from the options given below: