The document describes various types of microbial cultures, including batch, continuous, and synchronous cultures, which are methods for growing microorganisms under controlled conditions. It outlines the six phases of batch culture: lag, acceleration, exponential growth, deceleration, stationary, and death phases, as well as the mechanisms and devices used in continuous cultures, such as chemostats and turbidostats. Additionally, it highlights the importance of synchronous cultures for studying cell cycles and growth kinetics, emphasizing environmental factors that influence microbial growth.

1. BATCH ,CONTINOUS AND SYNCHRONOUS CULTURE
SUBMITTED TO;
DR DEEPTI DSOUZA
SUBMITTED BY;
TEJASWINI R
239232

2. WHAT ARE THESE CULTURE’S ?
A microbiological culture, or microbial culture, is a method of
multiplying microbial organisms by letting them reproduce in
predetermined culture medium under controlled laboratory
conditions. Microbial cultures are foundational and basic diagnostic
methods used as research tools in molecular biology.

3. 1) BATCH CULTURES
2) 6 PHASES
3) CONTINOUS CULTURE
4) SYNCHRONUS CULTURE
5) APPLICATION
6) ENVIRONMENTAL FACTORS ON GROWTH
CONTENTS

4. BATCH CULTURE
Batch culture is a closed culture system that contains limited amounts of
nutrients.
In batch culture the sterile growth medium is inoculated with appropriate
microorganisms and culture proceeds without addition of any fresh growth
medium.
• After inoculating the medium and start measuring the biomass at different time
intervals, you may find six different phases.
• Under this conditions usually six phases are observed.

5. Ⅰ. LAG PHASE
Ⅱ. ACCELERATED PHASE
Ⅲ. EXPONENTIAL GROWTH PHASE
Ⅳ. DECELERATED GROWTH PHASE
Ⅴ. STATIONARY PHASE
Ⅵ. DEATH PHASE
6 PHASES

6. Ⅰ. LAG PHASE
• The time between inoculation and beginning of multiplication is known as LAG PHASE.
• Lag phase is an initial phase period of cultivation during which the change of cell
number is zero or negligible.
• During this phase, there is an increase in size of bacteria but no appreciable increase
in number of bacterial cells.
• Even though the cell number doesn’t increases, the cells may grow in size during this
period.
• Duration- It may vary from 1 hour to several days.

7. Ⅱ. ACCELERATION PHASE
• At the end of lag phase, when growth begins the division rate
increases gradually and reaches a maximum value, and it is
called acceleration phase.

8. Ⅲ. LOG / EXPONENTIAL PHASE
• This phase is characterized by Rapid exponential cell growth (i.e.,1 to 2 to 4 to
8 and …..)
• The bacterial population doubles during every generation.
• Cell division occurs in this phase
• The bacterial cells are small and uniformly stained

9. • Under the log phase the cell mass undergoes several doublings and specific growth rate remains
constant due to enough nutrients.
• When plotted on logarithmic graph paper, the log phase appears as a steeply sloped straight line
• Log phase is expressed as,
dx/dt = µx
Where;
x = conc of microbial mass
t = time
µ = specific growth rate

10. IV. DECELERATED GROWTH PHASE
• The end of the exponential phase occurs when the nutrients depleted or toxic
metabolites accumulate in the system.
• During this phase growth rate decreases

11. V. STATIONARY PHASE
• During this phase that the culture is at its greatest population density.
• However, death rate of bacteria exceeds the rate of replication of bacteria
• Endospores start forming during this stage.
• Bacteria become gram variable and show irregular staining.
• Many bacteria start producing exotoxins

12. FACTORS AFFECTING THE PHASE
• Nutrient limitation –essential nutrient is severely depleted, population growth
will slow
• Aerobic organisms are often are limited by O2 availability
• The cells beneath the surface will not be able to grow unless the culture is
shaken or aerated in another way
• Due to accumulation of toxic waste products

13. VI. DEATH PHASE
• During this phase, the bacterial population declines due to death of cells.
• The decline phase starts due to
(A) accumulation of toxic products and autolytic enzymes and
(B) exhaustion of nutrients.
• Some cells assume various shapes, becoming long, filamentous rods or branching
• Some develop without a cell wall and are referred to as protoplasts, spheroplasts.
• Even when bacterial cells were transferred to fresh medium, no cellular growth was
observed. Because loss of viability was often not accompanied by loss in total cell
number, it was assumed that cells died but did not lyse.

15. CONTINUOUS CULTURE
• A process where inputs and outputs flow continuously through duration of
process
• Continuous culture is to keep a culture growing indefinitely.
• This can be done if :
1. Fresh nutrients are continuously supplied
2. Accumulated cells and waste products are removed at the same rate
3. Temp and ph are maintained

16. • The Cultured vessel designed for Continuous Culture is called as CHEMOSTAT
This has a fixed volume and flow rate and thus having fixed dilution rate.
Medium displaces equal volume of culture for Continuous production of cell.
Formation of new biomass balanced by loss of cells from vessel.

17. CHEMOSTAT
The cultured vessel designed for continuous
culture is called as CHEMOSTAT

18. TURBIDOSTAT
• Another device, also used in this method called
Turbidostat
• Turbidostat differs from Chemostat in several
ways
• This dynamically adjust the flow rate to make
turbidity constant
• Photoelectric device is used to monitor the cell
density

19. • Photocell measures the turbidity of the culture in the growth vessel. The flow
rate of media is automatically regulated to maintain the cell density
• The dilution rate in this varies rather than remaining constant, and medium
contains excess nutrients.
• Turbidostat operates best at high dilution rates; whereas chemostat is most
stable and effective at lower dilution rates.

21. Advantages
•Growth rate is higher as nutrients are continuously added to the fermentation
tank
•Continuous cultures are more efficient as the fermenter operates continuously
•Very useful for processes involving the production of primary metabolites
Disadvantages
•Set up is more difficult, the maintenance of required growing conditions can
be difficult to achieve
•If contamination occurs, huge volumes of product may be lost

22. SYNCHRONOUS CULTURE
• A synchronous culture is a cell culture which contains the cells that are all in the
same growth stage.
• Synchronized cultures must be composed of cells which are all at the same
stage of the bacterial cell cycle.
• Measurements made on synchronized cultures are equivalent to
measurements made on individual cells

23. • Synchronous Culture = cells of the culture remain at the
same stage of growth
• The cells of this culture divide at a time
• Their growth curve forms a zig zag pattern.

24. • The easiest way to synchronize bacterial growth is to add some cytostatic agents so
that cells don’t divide and they all maintain the same state of metabolism and cell
cycle.
• When the cytostatic agent is removed, all cells start to divide at the same time.
Cytostatic agents slow down or stop the growth of specific cells by inhibiting their cell
division
Ex ; Bendamustine, Chloromethine , Mitomycin

25. HOW CAN WE OBTAIN SYNCHRONOUS CULTURE
• Synchronous culture can be obtained by eliminating the essential nutrient
from the growth medium and later re-introduce it.
• The chemical growth inhibitors can be used to stop cell growth.
• When the growth is completely stopped for all cells, then remove the inhibitor
from the culture and the cells will begin to grow synchronously.

26. Application of synchronous culture
• Synchronous culture helps in the separation of the smallest cells from an
exponentially growing culture.
• In the laboratory it is used to study the cell cycle.
• Important in the study of genetics and metabolism.

28. KINETICS OF GROWTH CULTURE
• During the exponential phase each microorganism is dividing at constant intervals . Thus the
Population will double in number during a specific length of time called as GENERATION TIME or
DOUBLING TIME
log N - log N
t 0
0.301
n =
Where n = the number of generation in time t
No= the initial population
Nt = the population at time t

29. The rate of growth during the exponential phase in batch culture can be expressed in terms of
Specific Growth Rate Constant (k )
k = n/t
k =log Nt – log No
0.301 t
The time it takes a population to double in size i.e. the mean generation time or doubling time ( g )
where (t=g)
Nt = 2N0
Therefore,
k = log 2N0 – log No
0.301 t
k = 1/g OR g = 1/k
Therefore, mean generation time g = 1/k

30. INFLUENCE OF ENVIRONMENTAL FACTORS ON GROWTH
1. Solutes and water activity
2. pH -6.5 to 8.0
3. Temperature
4. Oxygen concentration
5. Pressure

32. REFERENCE
• Powar C B , Daginawala H F, ‘General Micro vol III’ (2003). Himalaya Publishing
House, Mumbai, page no 472-482
• Willey ,Sherwood , ‘Prescott 7th Edition’ (2008).McGraw Hill , New York, page
no 123-127
• https://www.studocu.com/in/document/manonmaniam-sundaranar-
university/microbial-microbiology/continuous-and-synchronous-culture-of-
bacteria/53996607