Transcript Bacterial growth

Bacterial growth:
• Bacterial Growth Curve: The schematic
growth curve shown below is associated
with simplistic conditions known as a batch
culture. It refers to a single bacterial
culture, introduced into and growing in a
fixed volume with a fixed (limited) amount
of nutrient. Industrial situations involving
MIC tend to be much more complex in
nature than such a simplified model.
Lag Phase:
• Bacteria are becoming "acclimated" to the
new environmental conditions to which
they have been introduced (pH,
temperature, nutrients, etc.). There is no
significant increase in numbers with time.
Exponential Growth Phase:
• The living bacteria population increases
rapidly with time at an exponential growth
in numbers, and the growth rate increasing
with time. Conditions are optimal for
growth.
Stationary Phase:
• With the exhaustion of nutrients and buildup of waste and secondary metabolic
products, the growth rate has slowed to
the point where the growth rate equals the
death rate. Effectively, there is no net
growth in the bacteria population.
Death Phase:
• The living bacteria population decreases
with time, due to a lack of nutrients and
toxic metabolic by-products.
Other stuff:
Metabolites:
• Primary:
e.g. amino acids, proteins, nucleic acids.
They are substances produced by an
organism as part of it’s normal growth.
Matches the growth curve of the
bacterium.
• Secondary metabolites
e.g. antibiotic chemicals. Growth is different
.. Growth starts later than the normal
growth phase.
Not all micro-organisms produce secondary
metabolites