A tunable heterologous phosphatidylcholine biosynthetic system reveals distinct phosphatidylcholine requirements for strong and weak acid responses in Acetobacter pasteurianus

Acetic acid bacteria, including the genera Acetobacter and Komagataeibacter, utilize phosphatidylcholine (PC) as a major membrane component, which plays an important role in their membrane physiology. However, the significance of PC abundance within the membrane remains speculative. Here, we constructed a mutant strain of A. pasteurianus through genome modification, enabling choline-dependent PC production. This mutant exhibited different dependencies on PC levels in response to strong and weak acid stress, requiring higher PC levels under strong acid stress but lower levels under weak acid stress. These findings provide new insights into the membrane-based mechanisms of acid-stress response in A. pasteurianus.