Movement Mechanisms Harness Lévy Flight for Energy-Efficient Wastewater Treatment in Microalgae-Bacteria Systems.

Microalgae-bacteria symbiosis system is significant for sustainable and low-carbon wastewater treatment, with self-aggregation being key to its stable operation and effective pollutant removal. Cellular motility is the main driving force behind self-aggregation, crucial for symbiosis stability, but the characteristics and patterns involved still remain largely unexplored. Here, cellular movement dynamics into the microalgae-activated sludge model (ASM3) is incorporated, enabling synchronized simulation of metabolic activities and movement behaviors through physical and biochemical interactions in bioreactor systems. These findings indicate that microalgae induce bacterial movement towards Lévy flights, thereby increasing the bacterial encounter rate by 12.20%, augmenting signaling molecule concentration and biomass by 20.0% and 27.3%, respectively, which in turn strengthens the bacteria self-aggregation effect. Through practical reactor operations with metagenomic analysis, the efficacy of this model in elucidating self-aggregation is further corroborated, improving system stability and pollutant removal efficiency. An optimized microalgae-bacteria system reduces energy costs associated with cellular aggregation processes, economizing on the cost of chemotaxis-related proteins. This study not only elucidate the unique role of Lévy flight in self-aggregation, enhancing the understanding of microalgae-bacteria symbiosis, but also establish response mechanisms between motility patterns and operation dynamics. This allows for targeted regulation across various biosystems, ensuring cost-effective wastewater treatment and proactive prediction.