Phases of Growth in Batch Culture

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Batch culture: A close system culture of algae in which there will be no supply of withdrawal of culture medium and biomass into or out of the culture vessel. In this type of culture the amount of medium and inoculum are known and specific.

Batch culture curve. Source (Details will be added later)

a. Lag phase

It is the phase where the inoculum acclimatize to the new environment. It is very crucial phase because in this phase, it is determined whether the organism is going to be metabolically active or inactive. There are physical and chemical factors which regulate this phase.

b. Acceleration phase

It is the shift up phase. Here cell divides and DNA replication occurs so cell number or biomass start to increase. Synthesis of growth parameter starts.

RNA – Enzyme – DNA – Cell division – Cell increase.

c. Log phase or exponential phase

All the requirements are present for further division of cell. Balalnced growth that is all the growth parameter uniformly increase. Organisms double in number agter regular intervals.

d. Decelaration phase

DNA synthesis reduces resulting the reduction of cell number. It is the shift down phase. Here synthesis of growth parameter stops.

No mRNA – No protein – No DNA – Cell division stops – Cell number doesn’t increase

e. Stationary phase

Number of dead cells is equal to the increase of the number of cell i.e. R/P = 1 i.e Rate of respiration and photosynthesis is equal.

f. Decline phase

Cell death and lysis occurs. The number of dead cells is higher than the number of cell division i.e. R/P is greater than 1.

 

Source:

    1. Textbook of Algae by O P Sharma