2.2. Morphological Observation of Gluten-Degrading Bacteria Using a Scanning Electron Microscope

Morphology of the bacterium was observed using a scanning electron microscope (SEM; Nanoeye, SNE-3000M; SEC Co., Ltd., Suwon, Republic of Korea). An overnight culture (approximately 6 log CFU/mL, TSB, 30 °C, and 15 h) of the bacterium was transferred to fresh TSB and incubated at 30 °C for 8 h. Then, 100 µL of the bacterial culture was filtered using a sterile polycarbonate membrane (0.2 µm pore; Advantech Toyo Kaisha Ltd., Tokyo, Japan) and washed with phosphate-buffered saline (PBS; pH 7.2). The bacterium was fixed with 100 µL of 2% glutaraldehyde for 30 min, washed with PBS (pH 7.2), dehydrated in a graded ethanol series (25–95%), added with t-Butyl alcohol, allowed to stand for 30 min, and freeze-dried. After platinum coating, the bacterium was observed at ×10,000 magnification using SEM set at 30 kV.