This study explores the production of polysaccharides (PS) in the strain Pf2289 of the food species Propionibacterium freudenreichii. Pf2289 presents characteristics atypical of the species: a molar-shaped morphotype upon plating, and cells strongly aggregative in liquid medium. When plating Pf2289, another morphotype was observed with a 4% frequency of appearance: round-shaped colonies, typical of the species. A clone was isolated, designated Pf456. No reversibility of Pf456 towards the molar-shaped morphotype was observed. Pf2289 was shown to produce a surface polysaccharide (PS) bound to the cell wall, mainly during the stationary growth phase. Meanwhile, Pf456 had lost the ability to produce the PS. AFM images of Pf2289 showed that entangled filaments spread over the whole surface of the bacteria, whereas Pf456 exhibited a smooth surface. Adhesion force maps, performed with concanavalin-A grafted probes, revealed twice as much adhesion of Pf2289 to concanavalin-A compared to Pf456. Furthermore, the length of PS molecules surrounding Pf2289 measured at least 7 μm, whereas it only reached 1 μm in Pf456. Finally, the presence of PS had a strong impact on adhesion properties: Pf2289 did not adhere to hydrophobic surfaces, whereas Pf456 showed strong adhesion.

这项研究探索了食品类弗氏丙酸杆菌的Pf 2289菌株中多糖（PS）的产生。Pf 2289表现出该物种的非典型特征：电镀后呈摩尔型形态，细胞在液体培养基中强烈聚集。电镀Pf 2289时，观察到另一种形态型，出现频率为4％：圆形菌落，典型的菌种。分离出克隆，命名为Pf456。未观察到Pf 456对臼齿形形态的可逆性。f已显示2289主要在固定生长期产生结合至细胞壁的表面多糖（PS）。同时，Pf 456失去了生产PS的能力。Pf 2289的AFM图像显示缠结的细丝遍布细菌的整个表面，而Pf 456则显示光滑的表面。用伴刀豆球蛋白A移植的探针进行的粘附力图显示，Pf 2289对刀豆球蛋白A的粘附力是Pf 456的两倍。此外，围绕Pf 2289的PS分子的长度至少为7μm，而仅达到1μm Pf 456中的厚度为μm。最后，PS的存在对粘合性能有强烈影响：Pf 2289不会粘附到疏水表面，而Pf 456则显示出很强的粘附力。