Analysis of the Cell Surface Hydrophobicity of Yoghurt Fermentation Bacteria

The cell surface hydrophobicity (CSH) of lactic acid bacteria was considered to colonization and adhesion, and playing a prebiotic function in the digestive tract. Therefore, CSH of yoghurt fermentation bacteria most commonly used was analyzed, such as Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus to identify initially CSH and the influencing factors of CSH of these strains and provided a theoretical basis for the future production of high-quality dairy fermentation agents and probiotics. The method of bacterial adhesion to hydrocarbons (BATH) was utilized to determine CSH of these strains and used the different conditions to process the cell. Through this research, the results was that L. acidophilus had a strong CSH, greater than L. bulgaricus and S. thermophilus. And the influencing factors of CSH of L. acidophilus were time, temperature, pH, concentration, Ca2+ and protease. But CSH was significantly reduced by trypsin and pepsin. CSH L. acidophilus was connected with the adhesion ability. In addition, it was speculated that some substances which could mediate CSH of L. acidophilus may be a class of proteins. Therefore, in the process of dairy fermentation agent, these factors could be controlled to obtain high-quality products.