Petry S, Furlan S, Crepeau M J, Cerning J, Desmazeaud M
Unité de Recherches Laitières et Génétique Appliquée, INRA, Jouy-en-Josas Cedex, France.
Appl Environ Microbiol. 2000 Aug;66(8):3427-31. doi: 10.1128/AEM.66.8.3427-3431.2000.
We developed a chemically defined medium (CDM) containing lactose or glucose as the carbon source that supports growth and exopolysaccharide (EPS) production of two strains of Lactobacillus delbrueckii subsp. bulgaricus. The factors found to affect EPS production in this medium were oxygen, pH, temperature, and medium constituents, such as orotic acid and the carbon source. EPS production was greatest during the stationary phase. Composition analysis of EPS isolated at different growth phases and produced under different fermentation conditions (varying carbon source or pH) revealed that the component sugars were the same. The EPS from strain L. delbrueckii subsp. bulgaricus CNRZ 1187 contained galactose and glucose, and that of strain L. delbrueckii subsp. bulgaricus CNRZ 416 contained galactose, glucose, and rhamnose. However, the relative proportions of the individual monosaccharides differed, suggesting that repeating unit structures can vary according to specific medium alterations. Under pH-controlled fermentation conditions, L. delbrueckii subsp. bulgaricus strains produced as much EPS in the CDM as in milk. Furthermore, the relative proportions of individual monosaccharides of EPS produced in pH-controlled CDM or in milk were very similar. The CDM we developed may be a useful model and an alternative to milk in studies of EPS production.
我们开发了一种化学成分明确的培养基（CDM），其中含有乳糖或葡萄糖作为碳源，该培养基能够支持两株德氏乳杆菌保加利亚亚种的生长和胞外多糖（EPS）产生。研究发现，影响该培养基中EPS产生的因素包括氧气、pH值、温度以及培养基成分，如乳清酸和碳源。EPS在稳定期产量最高。对在不同生长阶段分离的、在不同发酵条件（不同碳源或pH值）下产生的EPS进行成分分析，结果表明其组成糖类相同。德氏乳杆菌保加利亚亚种CNRZ 1187菌株产生的EPS含有半乳糖和葡萄糖，而德氏乳杆菌保加利亚亚种CNRZ 416菌株产生的EPS含有半乳糖、葡萄糖和鼠李糖。然而，各个单糖的相对比例有所不同，这表明重复单元结构可能会根据特定的培养基变化而有所不同。在pH值控制的发酵条件下，德氏乳杆菌保加利亚亚种菌株在CDM中产生的EPS与在牛奶中产生的一样多。此外，在pH值控制的CDM或牛奶中产生的EPS的各个单糖的相对比例非常相似。我们开发的CDM可能是研究EPS产生的一个有用模型，并且可替代牛奶。
