Boosting Algal Bloom by Five-Fold with AIEgens: Towards the Development of Biofactory

Human population is now faced with grand challenges such as global warming, food shortage and energy sustainability, which could be partially solved by massively increasing the growth and yield of photosynthetic organisms which capture the light energy to convert carbon dioxide and water into usable chemical energy. Cyanobacteria and eukaryotic microalgae are considered as attractive targets to be exploited by the algal factory because of their fast growth, low cost cultivation, less arable land and the diversity of high-value chemical substances produced. Many optical approaches have been introduced to increase the efficiency in artificial culturing systems, such as adding a luminescent layer that absorbs ultraviolet light and emits photosynthetic active radiation for cyanobacteria. In this work, we introduced luminogens with aggregation-induced emission characteristics (AIEgens) into the growth medium of a marine cyanobacteria. These hydrophobic AIEgens formed highly emissive luminogenic aggregates in the aqueous <a>medium and</a> dispersed around the cyanobacteria. Remarkedly, the number of cyanobacteria incubated in the medium with AIE aggregates was 5-fold more than the control group after 14-day culturing. The increased photosynthetic active radiation and the change of cyanobacteria protein expression in photosynthesis and metabolism might be the reason. Our study is the first using organic luminogenic aggregates as optical engineering inside the growth medium to dramatically increase the growth of cyanobacteria and demonstrated that AIEgens is promising technologies in the development of algal factories.