[Recent progress in algal-bacterial symbiotic and mutualistic systems]

Algal-bacterial symbiotic and mutualistic systems enhance community stability and functional performance through interspecies cooperation and signal exchange, demonstrating considerable potential in environmental remediation and sustainable biomanufacturing. This review systematically summarizes the fundamental interaction types and underlying mechanisms of algal-bacterial symbiosis and mutualism, with a particular focus on enabling technologies for the rational reconstruction of engineered mutualistic consortia and their emerging applications in environmental remediation and biomanufacturing. Different interaction modes, including mutualism, commensalism, parasitism, and endosymbiosis, are comparatively discussed, together with key regulatory mechanisms such as chemical signaling, nutrient exchange, horizontal gene transfer, and homeostasis maintenance under abiotic stress conditions. At the technical level, this paper introduces the recent advances in single-cell dynamic monitoring approaches, artificial intelligence-driven design platforms, and synthetic community engineering strategies integrating both top-down and bottom-up methodologies. Furthermore, this paper discusses the potential applications of algal-bacterial mutualistic systems in wastewater remediation, aquaculture, bioenergy recovery, and sustainable bioproduction and points out the current research challenges related to mechanism understanding, species specificity, long-term system stability, and ecological risk assessment. Finally, this review proposes that interdisciplinary approaches integrating multi-omics analyses, computational modeling, and controllable environmental validation will facilitate the development of efficient, robust, and sustainable algal-bacterial symbiotic systems, thereby providing theoretical guidance and technical support for advancing synthetic biology-driven resource utilization and green biomanufacturing.