## 2 Materials and Methods
### GC-MS Analysis of CMFA Composition  
The cell membrane debris was freeze-dried to prepare fatty acid methyl ester. The 100 mg of cell membrane debris was put into a clean EP tube, and 4 mL (1:1, vol/vol) chloroform methanol solution and 2 mL 0.88% NaCl solution were successively added into EP tube (marked as No. 1), and they were mixed by vortexing for 30 s. The mixture was centrifuged at room temperature at 3500 r/min for 15 min, and stood for 10 min. The lower layer liquid was pipetted and transferred to another clean test tube (marked as No. 2). The 2 mL of methylene chloride was added into the test tube (No. 1), vortexed for 30 s, and centrifuged at 3500 r/min for 15 min. Subsequently, the lower layer liquid from second time centrifugation was transferred into to the same test tube (No. 2) containing liquid from the first-time centrifugation. The lower layer liquid from the two centrifugations was mixed and dried under a flow of nitrogen. After nitrogen drying, 2 mL of methylation reagent (H\({}_{2}\)SO\({}_{4}\)+MeOH) was added into the mixture, and vortexed for 30 s and incubated in water bath at 80 for 2 h. The mouth of the bottle containing the mixture was covered with a low temperature gauze during the water bath to prevent gas from escaping. After the water bath incubation, 2 mL of n-hexane and 1 mL of water were added to the solution, and vortexed for 30 s. The obtained mixture solution was centrifuged for 5 min at 2000 r/min. The up-layer liquid was pipetted and transferred to another clean bottle, 1 mL of ultrapure water was added into the bottle, and vortexed for 30 s, centrifuged at 2000 r/min for 5 min.  
Subsequently, the resultant supernatant was dried under a flow of nitrogen. The 200 uL of isooctane was added into the dried supernatant, vortexed for 30 s, and then stood for 5 min. The solution was then transferred to the sample bottle for test. GC-MS analysis of samples was completed by Meji Biotechnology Co., Ltd. (Shanghai, China).  
Measurement of Intracellular pH(pH\({}_{i}\)), ATP Concentration, Activity of ATPase and Glutathione Reductase  
The intracellular pH (pH\({}_{i}\)) in bacterial suspensions was measured by the fluorescence method developed by [PERSON] et al. (2018) using 2',7\"-Bis(2-carboxyethyl)-5(6)-carboxyfluorescein tetrakis (acetoxymethyl) ester as the fluorescent probe (MedChemExpress LLC).  
After cell crushing, ATP concentration and were determined using an ATP assay kit (Beytotime, Shanghai, China) according to the manufacturers' instruction. The ATP concentration was expressed as micromode per milligram protein (uM/mg protein).  
H\({}^{+}\)-ATPase can decompose ATP to produce ADP and inorganic phosphor. H\({}^{+}\)-ATPase activity was determined with the H\({}^{+}\)-ATPase assay kit (NJ)CBIO, China), and the content of inorganic phosphorus was measured at OD\({}_{\text{660 nm}}\), according to the manufacturers' instructions. The results were expressed as U/mg protein. One unit of ATPase referred to the amount of ATPase that produced 1 uM inorganic phosphorus from 1 mg tissue protein per hour at 37 \({}^{\circ}\)C by decomposing ATP.  
Glutathione reductase (GR) activity was determined by monitoring glutathione-dependent oxidation of NADPH at OD\({}_{\text{340 nm}}\) using the glutathione reductase assay kit (Beytotime, China) according to the manufacturers' instructions. NADPH oxidation corrections were conducted in the absence of GSSG, and the results were expressed as U/mg protein. One unit of GR represented the amount of GR that oxidized 1 nM NADPH per minute at 2 \({}^{\circ}\)C.  
Protein content was determined using a BCA protein assay kit (Beytotime, China) with bovine serum albumin as standard.