The application of bubble column photobioreactor for algal cultivation

Microalgae are the potential photosynthetic microorganisms that offer applications in the energy, food and feed sectors for a sustainable and green future. However, the utilization of microalgae in various sectors cannot assure scalability and economic sustainability because of its high cultivation costs. Developing cost-effective and high biomass-producing cultivation systems is a prerequisite for the commercialization of microalgal products. The use of photobioreactors has gained interest as it provides suitable conditions for high biomass productivity. Among different photobioreactors, the bubble column is more suitable due to its easy and energy-efficient operation, simple design, and convenient scalability. The first part of this chapter comprehensively covers the factors that affect the growth of microalgae in the bioreactor including light intensity and photoperiod, nutrient transport mechanisms, the impact of light exposure, CO2, and temperature on the cultivation system. This chapter mainly focuses on bubble column bioreactor its operational parameters, design principles, and process analytical technology (PAT) for lipids, proteins, and biomass concentration of microalgae to digitally automate and control the cultivation process. The scalability of bubble column PBRs requires a deeper understanding of the complex dynamics involved in the growth and development of photosynthetic microorganisms within a bubble column bioreactor. The second part covers the hydrodynamics of bubble column bioreactors involved in the interactions between the gas and liquid phases within the systems, and mechanisms involved in the dispersion of gas within a liquid medium.