Batch culture involves adding nutrients and microorganisms to a closed fermenter with nothing added or removed until the end of the process. Continuous culture maintains microorganisms in exponential growth by constantly adding nutrients and removing product from an open fermenter. Batch culture is easier to set up and control but can lose an entire batch to contamination, while continuous culture uses smaller vessels but is more difficult to control environmental factors.

1. Batch and continuous culture
• Batch culture:
– Fermentation carried out in a closed or batch fermenter
– Microorganisms and nutrient medium added and left for a period
of time
– Nothing added to or removed from the fermenter during the
process (except for venting of waste gases)
– Product separated at the end
– Temperature controlled and nutrients usually depleted at the
end
• Continuous culture:
– Fermentation carried out in an open fermenter
– Nutrients added and product removed at a steady rate
throughout the process
– Maintain microorganisms at exponential phase of growth
– pH, temperature and oxygen concentration as well as nutrient
and product levels should be kept constant
ALBIO9700/2006JK

2. • Advantage of batch culture over
continuous culture:
– The culture is easy to set up
– The environmental conditions are relatively
easy to control
– The types of vessels used can be used for
different processes at different times
– If the culture becomes contaminated, it is
only one batch that is lost
– The level of nutrients drops, which can create
the conditions necessary for the
microorganism to manufacture secondary
metabolite such as penicillin
ALBIO9700/2006JK

3. • Advantages of continuous culture:
– It can be carried out in smaller vessels (productivity
high)
– The high productivity for biomass and intra- and
extra-cellular enzymes is more cost effective
• Disadvantages of continuous culture:
– Microbial growth, clumping of cells and foaming tend
to block up inlet pipes
– Can be difficult to control all the environmental
factors – could lead to considerable amount of waste
– Not possible to create the low-nutrient, high-stress
conditions under which secondary metabolites such
as penicillin are produced
ALBIO9700/2006JK

4. ALBIO9700/2006JK