Effects of Temperature on Growth Characteristics of Bacillus Stearothermophlus

Abstract

SummaryThe maximum temperature at which B. 8tearothermophilu8 will grow is considerably decreased if a simple medium free of cofactors is used.Such an increase of thermosensitivity could be caused by an imbalance of the cellular system or a shortage of essential components which the organisms cannot produce from the simple medium at all or at the rate required, or by both of these factors.The length of the lag period is determined probably by both the adaptation mechanism to a different temperature and the recovery period from a thermal shock during the harvesting procedure.The number of generations which will grow in a simple, defined medium (MgS04 .7H20 0·08%, CaCh.2H20 0·018%, KN0 3 0·05%, NH4CI 0·28%, glycerol 4%, sodium glycerophosphate O· 6%, and glucose monohydrate 1 % in distilled water) at a given temperature is probably determined by the presence of an inhibitory mater:~l produced and sustained inside the cell as well as other factors. If the rate of formation of such a material is temperature-dependent, growth would be limited to fewer generations at higher temperatures. Experimental evidence supports such a suggestion.

Thermophilic blue-green algae and the thermal environment.

“…Medium D, with the addition of 0.1% tryptone and 0.1 % yeast extract, was also used successfully (46 to 79 C) for the culture of the nonsporulating bacterium T. aquaticus, obtained from hot springs and hot tap water (42). Sporulating, thermophilic bacteria (e.g., B. stearothermophilus) from hot springs and many other sources have been grown in a variety of complex and defined organic culture media (5), as well as in relatively simple medium composed of distilled water containing 0.08% MgSO4.7 H20, 0.018% CaCl2-2 H20, 0.05% KNO3, 0.28% NH4Cl, 4% glycerol, 0.6% sodium glycerophosphate, and 1 % glucose monohydrate, which was adjusted to pH 6.8 and sterilized by filtration through a membrane filter (47).…”