Trehalose

Lactiplantibacillus plantarum WCFS1 was selected as the experimental strain. The concentrations (vol/vol) of oleic acid (Tansoole) selected for testing were 0.5, 0.1, 0.05, 0.01, 0.001, 0.0005, and 0.0001%. The seed liquid was inoculated into MRS liquid medium at a seeding rate of 1% and then cultured at 37°C for 12 to 16 h. Once the culture had reached an optical density of 1 at 600 nm (OD 600 = 1), a 2-mL aliquot was collected, pelleted by centrifugation at 7,378 × g for 5 min, washed twice with 1 mL of sterile physiological saline and then centrifuged (7,378 × g, 5 min) to collect bacterial masses. Each resulting bacterial mass was resuspended in 1 mL of sterilized trehalose (100 g/L), sorbitol (100 g/L), or PBS (pH 6.5), respectively (Sangon Biotech), each of which contained different concentrations of oleic acid (PBS was used as a control).

Maltotriose, isoMaltose, isomaltriose, panose, nigerose and kojibiose were purchased from Carbosynth (Suzhou, Jiangsu, China). Maltose and dextran 70 were bought from Sigma-Aldrich (St. Louis, MS, USA). 4-Nitrophenyl-α-D-glucopyranoside (pNPG) and methyl-α-glucopyranoside were obtained from Solarbio Life Science (Beijing, China). Sucrose, trehalose and soluble starch were purchased from Sangon (Shanghai, China). Restriction enzymes were obtained from Thermo Fisher Scientific (Shanghai, China). Phanta Max Super-Fidelity DNA Polymerase was purchased from Vazyme (Nanjing, Jiangsu, China). All other reagents and chemicals were analytical grade.