Cross-feeding is a phenomenon that occurs within microbial communities, such as those found in the human gut, where one species of microorganism produces a substance that is used by another species as a nutrient. It’s a form of interaction and cooperation between different microbial species, where the byproducts of one become the food for another, facilitating growth and complex interactions within the ecosystem.1Smith, N. W., Shorten, P. R., Altermann, E., Roy, N. C., & McNabb, W. C. (2019). The Classification and Evolution of Bacterial Cross-Feeding. Frontiers in Ecology and Evolution, 7, 435231. doi: 10.3389/fevo.2019.001532Giri S, Oña L, Waschina S, Shitut S, Yousif G, Kaleta C, Kost C. Metabolic dissimilarity determines the establishment of cross-feeding interactions in bacteria. Curr Biol. 2021 Dec 20;31(24):5547-5557.e6. doi: 10.1016/j.cub.2021.10.019.
Here are some examples of of cross-feeding in the human gut:
Fermentation of dietary fibres:
Bacteria such as Bacteroides thetaiotaomicron break down complex dietary fibres into simple sugars. Other bacteria like Faecalibacterium prausnitzii consume these sugars, producing short-chain fatty acids (SCFAs) such as butyrate.3Murakami R, Hashikura N, Yoshida K, Xiao JZ, Odamaki T. Growth-promoting effect of alginate on Faecalibacterium prausnitzii through cross-feeding with Bacteroides. Food Res Int. 2021 Jun;144:110326. doi: 10.1016/j.foodres.2021.110326.
Lactic acid metabolism
Lactic acid bacteria like Lactobacillus acidophilus produce lactic acid. Other bacteria, such as the Megasphaera group and the Eubacterium hallii group can utilise this lactic acid, converting it into other compounds like propionate and butyrate.Shetty SA, Marathe NP, Lanjekar V, Ranade D, Shouche YS. Comparative genome analysis of Megasphaera sp. reveals niche specialization and its potential role in the human gut. PLoS One. 2013 Nov 18;8(11):e79353. doi: 10.1371/journal.pone.0079353.[/ref]4Duncan SH, Louis P, Flint HJ. Lactate-utilizing bacteria, isolated from human feces, that produce butyrate as a major fermentation product. Appl Environ Microbiol. 2004 Oct;70(10):5810-7. doi: 10.1128/AEM.70.10.5810-5817.2004.
Hydrogen metabolism
Bacteria like Clostridium species are well-known fermenters and producers of hydrogen gas. Methane products like Methanobrevibacter smithii consume hydrogen, and this enables Clostridium bacteria to continue their metabolism.5Smith NW, Shorten PR, Altermann EH, Roy NC, McNabb WC. Hydrogen cross-feeders of the human gastrointestinal tract. Gut Microbes. 2019;10(3):270-288. doi: 10.1080/19490976.2018.1546522.
Syntrophic Interactions:
Certain bacteria like Proteus species produce ammonia during protein metabolism. Other microbes such as Clostridium species can convert this ammonia to other nitrogen-containing compounds like nitrite, thereby helping to detoxify it.6Leclerc M, Bedu-Ferrari C, Etienne-Mesmin L, Mariadassou M, Lebreuilly L, Tran SL, Brazeau L, Mayeur C, Delmas J, Rué O, Denis S, Blanquet-Diot S, Ramarao N. Nitric Oxide Impacts Human Gut Microbiota Diversity and Functionalities. mSystems. 2021 Oct 26;6(5):e0055821. doi: 10.1128/mSystems.00558-21.7Amon, J., Titgemeyer, F., & Burkovski, A. (2010). Common patterns – unique features: Nitrogen metabolism and regulation in Gram-positive bacteria. FEMS Microbiology Reviews, 34(4), 588-605. doi: 10.1111/j.1574-6976.2010.00216.x
Where to find cross-feeding in the Chuckling Goat Gut Microbiome Test
You will find examples of cross-feeding throughout the Chuckling Goat Gut Micobiome Test. Cross-feeding creates a dynamic and balanced ecosystem in the gut, where different species support each other’s growth and survival, contributing to the overall health of the host. By highlighting this concept, we aim to illustrate the complex and cooperative nature of the microbial community, where the metabolic activity of one organism directly impacts others, leading to a more diverse and stable community.
Synonyms: Syntrophic relationships, syntrophy, commensal interactions, cooperative metabolism, interspecies cooperation, metabolic cooperation, metabolic coupling, mutualistic feeding, metabolic symbiosis.
Important disclaimer
The Chuckling Goat Gut Microbiome Handbook is an educational resource built to translate complex science into plain English. The information provided on this page is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your GP or other qualified health provider with any questions you may have regarding a medical condition. Always check with your GP for interactions with medications/health conditions before changing your diet or starting to take food supplements.
References
- 1Smith, N. W., Shorten, P. R., Altermann, E., Roy, N. C., & McNabb, W. C. (2019). The Classification and Evolution of Bacterial Cross-Feeding. Frontiers in Ecology and Evolution, 7, 435231. doi: 10.3389/fevo.2019.00153
- 2Giri S, Oña L, Waschina S, Shitut S, Yousif G, Kaleta C, Kost C. Metabolic dissimilarity determines the establishment of cross-feeding interactions in bacteria. Curr Biol. 2021 Dec 20;31(24):5547-5557.e6. doi: 10.1016/j.cub.2021.10.019.
- 3Murakami R, Hashikura N, Yoshida K, Xiao JZ, Odamaki T. Growth-promoting effect of alginate on Faecalibacterium prausnitzii through cross-feeding with Bacteroides. Food Res Int. 2021 Jun;144:110326. doi: 10.1016/j.foodres.2021.110326.
- 4Duncan SH, Louis P, Flint HJ. Lactate-utilizing bacteria, isolated from human feces, that produce butyrate as a major fermentation product. Appl Environ Microbiol. 2004 Oct;70(10):5810-7. doi: 10.1128/AEM.70.10.5810-5817.2004.
- 5Smith NW, Shorten PR, Altermann EH, Roy NC, McNabb WC. Hydrogen cross-feeders of the human gastrointestinal tract. Gut Microbes. 2019;10(3):270-288. doi: 10.1080/19490976.2018.1546522.
- 6Leclerc M, Bedu-Ferrari C, Etienne-Mesmin L, Mariadassou M, Lebreuilly L, Tran SL, Brazeau L, Mayeur C, Delmas J, Rué O, Denis S, Blanquet-Diot S, Ramarao N. Nitric Oxide Impacts Human Gut Microbiota Diversity and Functionalities. mSystems. 2021 Oct 26;6(5):e0055821. doi: 10.1128/mSystems.00558-21.
- 7Amon, J., Titgemeyer, F., & Burkovski, A. (2010). Common patterns – unique features: Nitrogen metabolism and regulation in Gram-positive bacteria. FEMS Microbiology Reviews, 34(4), 588-605. doi: 10.1111/j.1574-6976.2010.00216.x
