Generalities
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1. Lag phase: it corresponds to the time needed for microalgae to adapt to new
environmental conditions. The growth rate during this period is very low (Yuan-Kun
& Hui, 2004).
2. Exponential phase: during this phase, the growth rate of microalgae is at its
maximum, thanks to optimal environmental conditions (Andersen, 2005).
3. Stationary phase: is the period when the microalgae population reaches equilibrium
and undergoes no net growth, the rate of growth is being balanced by the rate of cell
death or inactivation (Yuan-Kun &Hui, 2004).
4. Death phase: After a complete halt in cell division, cells that die will not be replaced
(Fernandez-Reiriz et al., 1989).
Microalgal growth can be influenced by a number of factors and parameters that affect
the growth and productivity of microalgal biomass (Figure 4).
Figure 4: Schematic diagram of microalgae growth parameters (Razzak et al., 2017).
1.1.7. Microalgae culture systems
There are several microalgae cultivation systems used for commercial production or
laboratory research. Among the main cultivation systems, we distinguish: