Izawa Naoki, Hanamizu Tomoko, Iizuka Ryoko, Sone Toshiro, Mizukoshi Harumi, Kimura Kazumasa, Chiba Katsuyoshi
Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi-shi, Tokyo, 186-8650, Japan.
J Biosci Bioeng. 2009 Feb;107(2):119-23. doi: 10.1016/j.jbiosc.2008.11.007.
Hyaluronic acid (HA) is an important material for medical, cosmetic and food applications. HA is obtained commercially from rooster combs and the fermentation of streptococci. However, the safety problems such as hyaluronidase or exotoxin contamination remain controversial. To reduce the risk of hyaluronidase or exotoxin contamination, we attempted to isolate strains of Streptococcus thermophilus with high productivity of useful exopolysaccharides (EPSs) including HA from traditional dairy food products. Forty-six S. thermophilus strains were isolated from dairy food products, and examined of their HA production using a HA binding protein method. According to the results, six S. thermophilus strains produced EPSs including HA. S. thermophilus YIT 2084 had a markedly high HA productivity (approximately 8 mg/l). We focused on the high-molecular-mass fraction of EPS (2000 kDa) from S. thermophilus YIT 2084. By using high-performance liquid chromatography, it was found that a high-molecular-mass fraction of EPS included N-acetylglucosamine (54.4%) and glucuronic acid (45.6%), which are components of HA. Furthermore, 13C-nuclear magnetic resonance spectroscopy showed that the spectra of the high-molecular-mass fraction corresponded well to those of commercial HA. Here, we described for the first time that S. thermophilus, which is a generally recognized safe bacterium, produces HA. The novel HA-producing bacterium S thermophilus YIT 2084 has great potential for applications in the medical, cosmetic and food fields, although its culture conditions remain to be improved.
透明质酸（HA）是一种用于医学、化妆品和食品领域的重要材料。商业上，HA是从公鸡鸡冠和链球菌发酵中获得的。然而，诸如透明质酸酶或外毒素污染等安全问题仍存在争议。为降低透明质酸酶或外毒素污染的风险，我们试图从传统乳制品中分离出能高产包括HA在内的有用胞外多糖（EPSs）的嗜热链球菌菌株。从乳制品中分离出46株嗜热链球菌菌株，并使用HA结合蛋白法检测它们的HA产量。结果显示，有6株嗜热链球菌菌株产生了包括HA在内的EPSs。嗜热链球菌YIT 2084的HA产量显著较高（约8mg/l）。我们聚焦于嗜热链球菌YIT 2084的EPS高分子质量部分（2000kDa）。通过高效液相色谱法发现，EPS的高分子质量部分包含N - 乙酰葡糖胺（54.4%）和葡萄糖醛酸（45.6%），它们是HA的组成成分。此外，13C - 核磁共振光谱表明，该高分子质量部分的光谱与商业HA的光谱非常吻合。在此，我们首次报道了一般认为安全的嗜热链球菌能产生HA。新型HA产生菌嗜热链球菌YIT 2084在医学、化妆品和食品领域具有巨大的应用潜力，尽管其培养条件仍有待改进。
