Microalgae-based carbon capture and utilization: A critical review on current system developments and biomass utilization

Abstract

Carbon capture and utilization (CCU) is an emerging technology with commercial potential to convert atmospheric carbon dioxide (CO₂) into net zero or negative emission products. In microalgae-based CCU, microalgae utilize CO₂ and sunlight to generate biomass for commercial applications. This paper reviews the current state of microalgal culture development for CCU and highlights its potential contribution to addressing climate change challenges. Current microalgal culture systems have not been designed for high throughput biomass growth and carbon capture. Raceways, high-rate algal ponds, and photobioreactors are the most widely used for microalgal cultivation at a large-scale. The limitations of these systems are related to microalgal growth requirements. Ponds are operated at narrow depth to ensure sufficient light distribution and thus need a large land surface. CO₂ gas needs to be in a dissolved form for efficient utilization by microalgae. Innovative system designs to achieve optimized distribution of light, nutrient, and CO₂ utilization for enhanced biomass production are crucial to achieve large-scale CO₂ capture by microalgae. Data corroborated in this review highlights several innovative techniques to deliver CO₂ effectively and enhance light illumination to microalgal cells. Submerged and internal illuminations can enhance light distribution without compromising culture volume and land requirements. CO₂ delivery technique selections mainly depend on CO₂ sources. The carbonation column appears to be the best option regarding efficiency, easy operation, and simple design. The downstream processes of microalgal culture (i.e. harvesting, biomass utilization, and water reuse) are important to make microalgae-based CCU a significant contribution to global carbon mitigation solutions.

Graphical abstract

Keywords:

• Biomass utilization
• carbon capture and utilization
• carbon dioxide delivery
• light distribution
• microalgae
• microalgal harvesting

HANDLING EDITORS:

• Amit Bhatnagar and Yong Sik Ok

Acknowledgements

Luong N. Nguyen acknowledges the University of Technology Sydney for the Vice-Chancellor’s Postdoctoral Research Fellowship.

Disclosure statement

No potential conflict of interest was reported by the authors.