Utilizing wastewater and flue gas for enhancing biomass and high-value products from microalgae

Microalgae cultivation using wastewater has been conducted to treat wastewater and lower carbon footprints. Wastewater can contribute to microalgae culture by supplying nutrients such as nitrogen, phosphorus, and organic carbon sources. Meanwhile, greenhouse gas emissions from fossil fuel consumption are also increasing rapidly, and global warming is intensifying. To overcome this phenomenon, Carbon Capture, Utilization, and Storage technology, a highly efficient greenhouse gas treatment technology that can capture and separate CO₂, has been developed and comprehensively discussed in this review. As a technology for capturing carbon, microalgae are cultured by supplying high concentrations of CO₂ using industrial flue gas. In addition, microalgae are used for removing organic substances, phosphorus, and nitrogen in wastewater. Through such biological treatment processes, it is possible to simultaneously reduce CO₂, remove biocontaminants, and produce high-value-added substances. Recently, research has been conducted on promoting microalgae growth by supplying wastewater and flue gas by enabling mixotrophic cultivation of microalgae. The review finally provides that sewage and industrial flue gas have the potential to improve the productivity of microalgae, reduce cost, and encourage environmental sustainability. Graphical abstract: [Figure not available: see fulltext.].