Accession Number : AD0456166

Title :   FREEZING AND FREEZE-DRYING OF SERRATIA MARCESCENS SUSPENDED IN SODIUM CHLORIDE,

Corporate Author : ARMY BIOLOGICAL LABS FREDERICK MD

Personal Author(s) : Zimmerman, Leonard

Report Date : DEC 1964

Pagination or Media Count : 11

Abstract : Studies were made of the effects of NaCl upon the survival of Serratia marcescens after freezedrying or freeze-thawing. Freeze-dried cells showed lowest survival in the presence of 5% NaCl; higher and lower concentrations yielded higher recovery levels. Cell suspensions containing varied concentrations of NaCl were then frozen so that phase-transition crystallization of the salt took place. Upon thawing, these samples yielded a pattern of survival levels that was about a log higher but otherwise similar to that of the freeze-dried cells. When samples of the NaCl-containing suspensions were frozen so that phase-transition crystallization did not occur, little loss in the viable population of any suspension was observed. Other inorganic chlorides that underwent phase-transition crystallization on freezing were as toxic as NaCl to S. marcescens, but other chlorides (such as MgCl2) that did not separate out in this manner were nontoxic. Mixtures of NaCl and MgCl2 did not undergo phase-transition crystallization on freezing and also were nontoxic to S. marcescens. (Author)

Descriptors :   (*SERRATIA MARCESCENS, FREEZING), FREEZE DRYING, SODIUM COMPOUNDS, CHLORIDES, VIABILITY, TOXICITY, SURVIVAL(PERSONNEL), PHYSIOLOGY, MAGNESIUM COMPOUNDS, CRYSTALLIZATION.

Distribution Statement : APPROVED FOR PUBLIC RELEASE