Bioprocessing presentation

DIFFERENCES BETWEEN BATCH AND CONTINUOUS CULTURES INDEX BATCH CULTURE CONTINUOUS CULTURE DIFFERENCES BETWEEN BATCH AND CONTINUOUS CULTURES

BATCH CULTURE It is a closed culture system which contains an initial limited amount of nutrients. Bacteria will grow until necessary growth factor becomes exhausted and becomes limiting. No additional nutrients are added to the closed system called as batch culture.

Batch culture divided into 4 phases LAG PHASE LOG PHASE STATIONARY PHASE DECLINE PHASE

CONTINUOUS CULTURE This is an open process in which microbial cultures also grow continuously in log phase. The exponential growth in batch cultures can be prolonged by the addition of more substrate but it will lead to the overflow device is fitted to the fermentor such that the added medium displace an equal volume of culture from the vessel than the continuous production of the cell is achieved such types of system are called as continuous culture .

DIFFERENCES BATCH CULTURE CONTINUOUS CULTURE It is a closed culture system which contain an initial limited amount of nutrients. It is open culture system where nutrients are continuously fed.

Batch culture undergo four phases i. e Batch culture undergo four phases i.e., lag , log ,stationary ,decline. The change in cell biomass can be represented as follows : dx =µx dt Exponential phase can be prolonged by the addition of fresh nutrients. The change in cell biomass can be represented as follows : dx=µx ̶ dx dt

The chances of contamination are less The chances of contamination are less. The Biomass productivity represented as follows: Rbatch =xmax - x ti- tii The productivity is maximum only towards the end of the process. The chances of contamination are more. The biomass productivity represented as follows: Rconti=dx[1-tiii] T If operated at optimum diluted rate under steady state conditions productivity is always constant and maximum

The culture requirements vary during the process i The culture requirements vary during the process i.e,in the beginning oxygen requirement and agitation requirement is less and as process proceed due to the increase in the cell density .oxygen demand and agitation requirement increases . Extensive labour is required only at the start and end of the process. The culture requirement remains constant i.e., constant amount of oxygen and agitation is required during the process. Extensive labour is required throughout the the process.

They can not be easily scaled up. The growth curve is j shaped. They can be easily scaled up. The effect of unproductive time i.e., tiii is less. The growth curve is sigmoidal. They can not be easily scaled up. The effect of unproductive time i.e.,tiii is more.

Simple control. it is easier to control reaction conditions (ph,pressure,temperature.). Complex control automatic control must be used .control of reactor conditions is more difficult .control must be exercised over the rate of flow of the material.

Preferable when production of small quantities of specific material are planned . Extraction of material only after all the actions are finished with the conclusion of reaction. Production of primary metabolites only. Examples : alcohol ,amino acids etc . Growth ,product formation and substrate utilization all terminate after a certain time interval. Preferable for large scale production. continuous extraction of products at all times during the reaction. Production of primary as well as secondary metabolites. Examples: antibiotics. Growth and product formation can be maintained for prolonged periods of time .

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