1. BACTERIAL GROWTH & REPRODUCTION
@ This is the division of one bacterium into two
daughter cells by binary fission.
@ The resulting daughter cells are identical to
the mother cell; hence "local doubling" of the
bacterial population occurs.

3. @ Bacteria increase in cell size and reproduce
by cell division.
@ Bacteria grow to a fixed size and then
reproduce through binary fission, which is
a form of asexual reproduction.
@ Under optimal conditions, bacteria can divide
rapidly, and bacterial populations can double
every 9.8 minutes, e.g. E. coli.

5. @ In cell division, two identical clone daughter
cells are produced.
@ Streptomyces produces aerial hyphae that
help to disperse the newly daughter cells.
@ Yeasts form budding which is a cell protrusion
that breaks away and forms a daughter cell

7. @ Some organisms live in communities (Biofilms)
that allow for increased nutrients supply and
protection from environmental stresses.
@ Some organisms (algae & cyanobacteria)
divide rapidly before nutrients become
limited.
@ Others produce antibiotic (Streptomyces) to
inhibit growth of other organisms.

9. Bacterial Growth Curve:
@ Bacterial growth in batch culture has seven
different phases:
# Lag phase
# Early log (exponential) phase
# Log phase
# Early stationery phase
# Stationary phase
# Early death phase
# Death phase

11. @ Lag phase:
# Bacterial adaptation to the growth conditions
# It is the period where the individual bacteria
are maturing and not yet able to divide.
@ Exponential phase:
# Called log phase or logarithmic phase.
# It is characterized by cell doubling at a
constant rate with each time period.
# Growth stops when the medium nutrients are
depleted or wastes products accumulate.

13. @ Stationary phase:
# The growth rate slows down due to nutrient
depletion and accumulation of toxic waste
products.
# This phase is reached as the bacteria begin
to exhaust the nutrients available to them.
# This phase is constant as the rate of
bacterial growth is equal to the rate of
bacterial death.
@ Death phase:
Bacteria run out of nutrients and die.

15. @ Specific growth rate:
It is number of divisions per cell per unit time
It depends upon the growth conditions, which
affect the frequency of cell division.
@ Bacterial growth is studied in batch culture
containing one medium, & in continuous culture
(chemostat) containing many media.
@ chemostat culture is done by incubating the
organism in a closed vessel.

17. Mathematical calculation of growth:
@ The number of organisms grown after a (t)
period can be calculated according to the
following equation:
Nt = N0 x 2n (1)
where
Nt = cell number at time t
N0 = starting number at time zero
n = number of doublings (generations).

19. Bacterial Counting Methods:
# Direct and individual counting by microscopy
and flow cytometry.
# Direct and bulk biomass measurement.
# Indirect and individual colony counting.
# Indirect and bulk counting by most probable
number (MPN), turbidity, & nutrient uptake.