保加利亚乳杆菌和嗜热链球菌生物膜形成研究

采用置片法和菌落计数法对嗜热链球菌(Streptococcus thermophilus)和保加利亚乳杆菌(Lactobacillus bulgaricus)在不同载体表面(椰果粒、不锈钢网布、塑料片、陶瓷片和玻璃片)上形成生物膜的能力进行研究。结果表明：椰果粒和不锈钢网布是适宜乳酸菌单菌生物膜形成的载体，培养7d椰果粒和不锈钢网布上的单菌生物膜初始菌密度可达107CFU/cm2，并且在后续培养中能稳定在3.2×106CFU/cm2左右；混菌生物膜菌密度连续7d稳定在1×107CFU/cm2左右。利用扫描电镜对S. thermophilus和L. bulgaricus形成的混菌生物膜进行观察，结果表明在椰果粒和不锈钢网布表面上S. thermophilus和L. bulgaricus形成典型的混菌生物膜结构。

Biofilm-forming Capabilities of Lactobacillus bulgaricus and Streptococcus thermophilus

The biofilm-forming capabilities of Streptococcus thermophilus and Lactobacillus bulgaricus on different carriers (coconut, stainless steel mesh, plastic sheet, glass sheet or ceramic parts) was studied by using placed slice and plate culture count methods. The results showed that stainless steel mesh and coconut were suitable carriers for biofilm formation. During 7 days, the CFU (colony-forming units) of the single-species biofilm on coconut and stainless steel mesh initially reached 1 × 107 CFU/cm2 and then was kept at 3.2 × 106 CFU/cm2. The mixed-species biofilm was stable at approximately 1 × 107 CFU/cm2 in continuous seven days. In addition, scanning electron microscope was used to observe mixed-species biofilm formed by S. thermophilus and L. bulgaricus, and a typical mixed-species biofilm was observed on coconut and stainless steel mesh.