Anammox bacteria regulate a mixotrophic lifestyle in response to osmotic stress

Anaerobic ammonium-oxidizing (anammox) bacteria were long regarded as strictly chemolithoautotrophic, yet recent evidence indicates that they can also utilize organic compounds, revealing a mixotrophic lifestyle. This capacity for organic substrate utilization may enhance their resilience under energy-limited or stressful conditions by supplying additional reducing power and metabolic precursors. In this study, we demonstrate that organotrophic metabolism is integrated with the osmoadaptive responses of anammox bacteria, providing mechanistic and operational insights for applying anammox processes in organic-rich saline wastewaters.