Maximizing algal growth in batch reactors using sequential change in light intensity

Area of Science:

• Biotechnology
• Algal Biotechnology
• Photobioreactor Engineering

Background:

• Algal growth is dependent on optimal light irradiance, which varies with culture density in photobioreactors.
• Photoinhibition and light limitation occur at low and high culture densities, respectively, impacting growth.
• Efficient light supply strategies are crucial for maximizing algal biomass production and photon use efficiency.

Purpose of the Study:

• To investigate the impact of light supply strategies on the growth of Neochloris oleoabundans in batch photobioreactors.
• To compare biomass concentration and growth rates under constant versus sequentially increasing light intensities.
• To determine the effect of tailored light strategies on photon use efficiency in dense algal cultures.

Main Methods:

• Cultivation of Neochloris oleoabundans in batch photobioreactors under controlled conditions.
• Measurement of growth rates and biomass concentrations for cultures under constant light.
• Comparison with cultures grown under sequentially increasing light intensities correlated with culture density.

Main Results:

• Sequential increase in irradiance levels resulted in up to a 2-fold higher biomass concentration compared to constant light.
• Tailored light supply did not negatively impact algal growth rates.
• Optimized light strategies led to reduced overall photon use per unit mass of generated algal biomass.

Conclusions:

• Light intensity management based on culture density is essential for efficient algal cultivation in photobioreactors.
• Sequential light increase strategies significantly enhance biomass yield and photon efficiency.
• This approach offers a viable method for optimizing large-scale algal biomass production.