The potential microalgae-based strategy for attaining carbon neutrality and mitigating climate change: A critical review

Hao Cheng¹Yi Liu¹Ziai Deng¹Xiulan Xie¹Chenglong Yang²Heer Baloch¹Zhanke Qin³Weicheng Xu¹Haojie Zhang³Jiayi Gao¹Abdul Jaleel^4*Maozhi Ren^5*

• ¹Institute of Urban Agriculture Chinese Academy of Agriculture, Chengdu, China
• ²Zhengzhou University School of Agricultural Sciences, Zhengzhou, China
• ³Department of Agricultural Engineering, Kizilsu Vocational Technical College, Kizilsu, China
• ⁴United Arab Emirates University College of Agriculture and Veterinary Medicine, Al Ain, United Arab Emirates
• ⁵Chinese Academy of Agricultural Sciences (CAAS), Beijing, China

In recent years, the impacts of global warming, including glacial melting, extreme weather events, food crises, and epidemics, have become increasingly severe, posing significant challenges to global sustainability. The primary driver of the current climate crisis is the substantial emission of greenhouse gases (GHGs), particularly carbon dioxide (CO2). Microalgae, as photoautotrophic microorganisms, offer a promising solution by utilizing CO2 for biosynthesis. Previous research indicates that microalgae can fix CO2 at rates exceeding 1.5 kg/m2/year under optimal conditions, and produce lipids with high content of unsaturated fatty acids. This review delves into recent advancements understanding the causes and effects of global warming, with a particular focus on agricultural GHG emissions. It critically examines the carbon sequestration mechanisms of microalgae and their potential as single-cell biofactories for carbon neutralization and biomanufacturing. The review highlights their ability to fix CO2 and produce high-value products such as biofuels, chemicals, pharmaceuticals, and foods. Among these species, the characteristics and value of seven edible microalgae are also described. We outline the technical and economic challenges associated with scaling up microalgae cultivation from laboratory to industrial scale, including the optimization of cultivation systems and the improvement of harvesting and processing techniques. This review serves as a useful and informative reference for the application of CO2 capture and high-value bioproducts by microalgae, aiming to provide a reference for the realization of carbon neutrality and the mitigation of climate change.