Recent advances in microalgae-driven carbon capture, utilization, and storage: Strain engineering through adaptive laboratory evolution and microbiome optimization

The potential of microalgae as a biological resource for carbon capture, utilization, and storage (CCUS) has been extensively discussed. Although genetic engineering methods have been employed to improve microalgal phenotypes, they often face challenges related to public concerns regarding genetically modified organisms. By contrast, adaptive laboratory evolution (ALE) and microbiome optimization have emerged as promising non-genetic modification strategies, with notable success in bacterial models. In microalgae, ALE has been employed to improve resilience against varying environmental and stress factors and increase carbon capture efficiency, and for the production of valuable bioproducts through gradual accumulation of beneficial mutations following manual or automated selection. Furthermore, advancements in the understanding of microbial symbiotic relationships in the phycosphere have facilitated microbiome optimization in microalgal cultivation systems, significantly improving their functionality and productivity. In this study, we provide a comprehensive overview of the latest advancements in ALE and microbiome optimization of microalgae for CCUS across different carbon emission scenarios, including flue gas, biogas, wastewater, and landfill leachate. We further discuss the current challenges and future directions for the integration of ALE with microbiome optimization, focusing on the potential synergies of these methodologies. Overall, ALE and microbiome optimization are promising approaches to direct microalgae for environmental and industrial CCUS applications, thereby reducing global carbon emissions and addressing climate change challenges.