Moens F, De Vuyst L
1 Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
Benef Microbes. 2017 May 30;8(3):473-490. doi: 10.3920/BM2016.0142.
Four selected butyrate-producing colon bacterial strains belonging to Clostridium cluster IV (Butyricicoccus pullicaecorum DSM 23266 and Faecalibacterium prausnitzii DSM 17677) and XIVa (Eubacterium hallii DSM 17630 and Eubacterium rectale CIP 105953) were studied as to their capacity to degrade inulin-type fructans and concomitant metabolite production. Cultivation of these strains was performed in bottles and fermentors containing a modified medium for colon bacteria, including acetate, supplemented with either fructose, oligofructose, or inulin as the sole energy source. Inulin-type fructan degradation was not a general characteristic among these strains. B. pullicaecorum DSM 23266 and E. hallii DSM 17630 could only ferment fructose and did not degrade oligofructose or inulin. E. rectale CIP 105953 and F. prausnitzii DSM 17677 fermented fructose and could degrade both oligofructose and inulin. All chain length fractions of oligofructose were degraded simultaneously (both strains) and both long and short chain length fractions of inulin were degraded either simultaneously (E. rectale CIP 105953) or consecutively (F. prausnitzii DSM 17677), indicating an extracellular polymer degradation mechanism. B. pullicaecorum DSM 23266 and E. hallii DSM 17630 produced high concentrations of butyrate, CO, and H from fructose. E. rectale CIP 105953 produced lactate, butyrate, CO, and H, from fructose, oligofructose, and inulin, whereas F. prausnitzii DSM 17677 produced butyrate, formate, CO, and traces of lactate from fructose, oligofructose, and inulin. Based on carbon recovery and theoretical metabolite production calculations, an adapted stoichiometrically balanced metabolic pathway for butyrate, formate, lactate, CO, and H production by members of both Clostridium cluster IV and XIVa butyrate-producing bacteria was constructed.
选取了四株产丁酸盐的结肠细菌菌株,分别属于梭菌属IV簇(普氏丁酸球菌DSM 23266和普拉梭菌DSM 17677)和XIVa簇(哈氏真杆菌DSM 17630和直肠真杆菌CIP 105953),研究它们降解菊粉型果聚糖的能力以及伴随的代谢产物生成情况。这些菌株在装有改良结肠细菌培养基的瓶子和发酵罐中培养,该培养基含有乙酸盐,并分别添加果糖、低聚果糖或菊粉作为唯一能源。菊粉型果聚糖降解并非这些菌株的普遍特征。普氏丁酸球菌DSM 23266和哈氏真杆菌DSM 17630只能发酵果糖,不能降解低聚果糖或菊粉。直肠真杆菌CIP 105953和普拉梭菌DSM 17677发酵果糖,并且能够降解低聚果糖和菊粉。低聚果糖的所有链长部分同时被降解(两种菌株均如此),菊粉的长链和短链部分要么同时被降解(直肠真杆菌CIP 105953),要么依次被降解(普拉梭菌DSM 17677),这表明存在一种细胞外聚合物降解机制。普氏丁酸球菌DSM 23266和哈氏真杆菌DSM 17630从果糖中产生高浓度的丁酸盐、一氧化碳和氢气。直肠真杆菌CIP 105953从果糖、低聚果糖和菊粉中产生乳酸、丁酸盐、一氧化碳和氢气,而普拉梭菌DSM 17677从果糖、低聚果糖和菊粉中产生丁酸盐、甲酸盐、一氧化碳和微量乳酸。基于碳回收率和理论代谢产物生成计算,构建了一个适用于梭菌属IV簇和XIVa簇产丁酸盐细菌成员产丁酸盐, 甲酸盐, 乳酸, 一氧化碳和氢气的化学计量平衡代谢途径。