Raffinose has become a major focus of research interest and recent studies have shown that besides beneficial bifidobacteria and lactobacilli, Escherichia coli, Enterococcus faecium and Streptococcus pneumoniae can also utilize raffinose and raffinose might lead to flatulence in some hosts. Therefore, it is required to find out the raffinose-metabolizing bacteria in the gut and the bacteria responsible for the flatulence. The BLASTP search results showed that the homologous proteins of glycosidases related to raffinose utilization are widely distributed in 196 of the 528 gut bacterial strains. Fifty-nine bacterial strains belonging to nine species of five genera were isolated from human feces and were found to be capable of utilizing raffinose; of these species, Enterococcus avium and Streptococcus salivarius were reported for the first time. High-performance liquid chromatography (HPLC) analysis of the supernatants of the nine species revealed that the bacteria could utilize raffinose in different manners. Glucose and melibiose were detected in the supernatants of Enterococcus avium E5 and Streptococcus salivarius B5, respectively. However, no resulting saccharides of raffinose degradation were detected in the supernatants of other seven strains, indicating that they had different raffinose utilization types from Enterococcus avium E5 and Streptococcus salivarius B5. Gas was produced with raffinose utilization by Escherichia coli, Enterococcus faecium, Streptococcus macedonicus, Streptococcus pasteurianus and Enterococcus avium. Thus, more attention should be paid to the raffinose-utilizing bacteria besides bifidobacteria and further studies are required to reveal the mechanisms of raffinose utilization to clarify the relationship between raffinose and gut bacteria.

中文翻译：

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人类肠道细菌对棉子糖的体外发酵†

棉子糖已成为研究兴趣的主要焦点，最近的研究表明，除了有益的双歧杆菌和乳杆菌外，大肠杆菌，粪肠球菌和肺炎链球菌也可以利用棉子糖，棉子糖可能会导致某些宿主的肠胃气胀。因此，需要找出肠道中的棉子糖代谢细菌和引起肠胃气胀的细菌。BLASTP搜索结果表明，与棉子糖利用有关的糖苷酶的同源蛋白广泛分布在528种肠道细菌中的196种中。从人类粪便中分离出属于五个属的九个物种的五十九个细菌菌株，发现它们能够利用棉子糖。这些物种中，鸟肠球菌和唾液链球菌是第一次报道。高效液相色谱（HPLC）分析这9个物种的上清液表明，细菌可以不同方式利用棉子糖。在鸟肠球菌E5和唾液链球菌B5的上清液中分别检测到葡萄糖和美利比糖。然而，在其他七个菌株的上清液中未检测到所得的棉子糖降解糖，这表明它们与禽肠球菌E5和唾液链球菌B5的棉子糖利用类型不同。大肠杆菌，粪肠球菌，棉子糖利用产生了气体。链球菌macedonicus，链球菌巴氏和肠球菌鸟。因此，除双歧杆菌外，应更加重视利用棉子糖的细菌，需要进一步研究以揭示棉子糖利用的机理，以阐明棉子糖与肠道细菌之间的关系。