Quorum sensing for carbon-neutral wastewater treatment: Mechanisms, challenges, technological pathways, and future prospects

Global climate targets demand a rapid transition to carbon neutrality across all industrial sectors, including wastewater management. Wastewater treatment plants are historically energy-intensive and remain significant sources of potent greenhouse gases, primarily nitrous oxide (N₂O) and methane (CH₄). Recent biological interventions have targeted quorum sensing (QS)—a microbial communication mechanism regulating gene expression and community behavior—to optimize biological treatment efficiency. However, the highly context-dependent and sometimes paradoxical effects of QS on simultaneous greenhouse gas mitigation and energy recovery remain poorly resolved. Here we synthesize recent advancements to show that QS operates as a master biological regulator of both direct emissions and energy consumption in wastewater ecosystems. Evidence indicates that QS distinctly modulates N₂O production through concentration- and signal-dependent pathways, while actively suppressing CH₄ escape and enhancing aerobic granulation to cut aeration energy demands. Furthermore, targeted QS deployment in anaerobic digestion accelerates direct interspecies electron transfer, substantially boosting methane recovery to offset operational energy use. These insights reveal that manipulating microbial social networks presents a viable, albeit complex, biological lever for balancing emission reductions with energy optimization. Ultimately, precision control of QS systems offers a transformative technological pathway for achieving carbon-positive wastewater infrastructure.