Temperature

1
Temperature Microbial Growth

• Temperature affects
• Enzyme activity
• Membrane fluidity
• Nutrient transport
• Ribosomes protein synthesis
• Pigment production (prodigiosin in Serratia
  marcescens)
• Pyschrophiles optimal growth temp -5 to 20?C
  (arctic antarctic)
• Mesophiles optimal growth temp 20 to 50 ?C
  (most bacteria)
• Thermophiles optimal growth temp 50 to 80?C
  (soil compost)
• Hyperthermophiles optimal growth gt 80?C
  (thermal vents volcanoes)

2
Osmotic Pressure

• Water activity availability of water to a cell
  for metabolism
• Osmosis water diffuses from areas of low to
  areas of high solute
• Hypotonic solute (NaCl) concentration lt on
  outside (water moves in)
• Hypertonic solute (NaCl) concentration gt on
  outside (water moves out)
• Plasmolysis cell shrinks lyses due to loss of
  water
• Halophiles require high salt concentrations
  (15-30)
• Archaea in salt water Halobacterium salinarium
• Halotolerant grow in moderate concentrations
  (11)
• Staph aureus on skin
• Osmophiles grow in excessive sugar
  concentrations