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Xiang S, Ye K, Li M, Ying J, Wang H, Han J, Shi L, Xiao J, Shen Y, Feng X, Bao X, Zheng Y, Ge Y, Zhang Y, Liu C, Chen J, Chen Y, Tian S, Zhu X. Xylitol enhances synthesis of propionate in the colon via cross-feeding of gut microbiota. Microbiome 2021; 9:62. [PMID: 33736704 PMCID: PMC7977168 DOI: 10.1186/s40168-021-01029-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 02/05/2021] [Indexed: 05/12/2023]
Abstract
BACKGROUND Xylitol, a white or transparent polyol or sugar alcohol, is digestible by colonic microorganisms and promotes the proliferation of beneficial bacteria and the production of short-chain fatty acids (SCFAs), but the mechanism underlying these effects remains unknown. We studied mice fed with 0%, 2% (2.17 g/kg/day), or 5% (5.42 g/kg/day) (weight/weight) xylitol in their chow for 3 months. In addition to the in vivo digestion experiments in mice, 3% (weight/volume) (0.27 g/kg/day for a human being) xylitol was added to a colon simulation system (CDMN) for 7 days. We performed 16S rRNA sequencing, beneficial metabolism biomarker quantification, metabolome, and metatranscriptome analyses to investigate the prebiotic mechanism of xylitol. The representative bacteria related to xylitol digestion were selected for single cultivation and co-culture of two and three bacteria to explore the microbial digestion and utilization of xylitol in media with glucose, xylitol, mixed carbon sources, or no-carbon sources. Besides, the mechanisms underlying the shift in the microbial composition and SCFAs were explored in molecular contexts. RESULTS In both in vivo and in vitro experiments, we found that xylitol did not significantly influence the structure of the gut microbiome. However, it increased all SCFAs, especially propionate in the lumen and butyrate in the mucosa, with a shift in its corresponding bacteria in vitro. Cross-feeding, a relationship in which one organism consumes metabolites excreted by the other, was observed among Lactobacillus reuteri, Bacteroides fragilis, and Escherichia coli in the utilization of xylitol. At the molecular level, we revealed that xylitol dehydrogenase (EC 1.1.1.14), xylulokinase (EC 2.7.1.17), and xylulose phosphate isomerase (EC 5.1.3.1) were key enzymes in xylitol metabolism and were present in Bacteroides and Lachnospiraceae. Therefore, they are considered keystone bacteria in xylitol digestion. Also, xylitol affected the metabolic pathway of propionate, significantly promoting the transcription of phosphate acetyltransferase (EC 2.3.1.8) in Bifidobacterium and increasing the production of propionate. CONCLUSIONS Our results revealed that those key enzymes for xylitol digestion from different bacteria can together support the growth of micro-ecology, but they also enhanced the concentration of propionate, which lowered pH to restrict relative amounts of Escherichia and Staphylococcus. Based on the cross-feeding and competition among those bacteria, xylitol can dynamically balance proportions of the gut microbiome to promote enzymes related to xylitol metabolism and SCFAs. Video Abstract.
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Affiliation(s)
- Shasha Xiang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Kun Ye
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua, 324302 China
| | - Jian Ying
- Nutrition and Health Research Institute, COFCO Ltd., Beijing, 102209 China
| | - Huanhuan Wang
- School of Medicine, Hangzhou Normal University, Hangzhou, 310018 China
- Laboratory of Aging and Cancer Biology of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121 China
| | - Jianzhong Han
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Lihua Shi
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua, 324302 China
| | - Jie Xiao
- Nutrition and Health Research Institute, COFCO Ltd., Beijing, 102209 China
| | - Yubiao Shen
- Yangtze Delta Institute of Tsinghua University, Jiaxing, 314000 China
| | - Xiao Feng
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Xuan Bao
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Yiqing Zheng
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Yin Ge
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Yalin Zhang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Chang Liu
- School of Food Science and Technology, Jiangnan University, Wuxi, 214122 China
| | - Jie Chen
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Yuewen Chen
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Shiyi Tian
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
| | - Xuan Zhu
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018 China
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