Utilizing nanobubble technology to improve Chlorella sorokiniana growth efficiency

Microalgae, as one of the major aquaculture products throughout the globe, is becoming more and more popular due to the plasticity of its applications. Like many aquaculture industries, microalgae production seeks for better yields but often faces challenges. Carbon dioxide insufficiency is one of the common bottlenecks of microalgae production due to the inefficient injection of CO 2 into the culture medium. This study investigates the impact of CO 2 nanobubble injection on the growth of Chlorella sorokiniana in outdoor photobioreactors. Given the unique properties of nanobubble, injecting CO 2 using a nanobubbler successfully increased the carbonate levels compared to the CO2 applied through an air stone (i.e. in the second treatment up to 113%). The enhancement of CO 2 injection efficiency promoted the growth of Chlorella sorokiniana and resulted in an 18% higher algal density than the traditional CO 2 injection method through air stones. Further, CO 2 nanobubbles had a 65% better algal density compared to only providing aeration. This study highlights the potential of CO 2 nanobubble technology in industrial applications, providing a cost-effective and efficient method for enhancing microalgae production.