Starch-degrading gut microbes Ruminococcus bromii and Bifidobacterium adolescentis differ in their ability to degrade
C E Klostermann1,2, M Fassarella3, E G Zoetendal3
1Biobased Chemistry & Technology, 4508Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
Beneficial Microbes
|May 1, 2025
Summary
Ruminococcus bromii efficiently degrades resistant starch type 3 (RS-3), while Bifidobacterium adolescentis struggles with certain RS-3 types. This highlights the need for specific microbial enzymes for effective RS-3 breakdown in the gut.
Area of Science:
- Microbiology
- Nutritional Science
- Gastroenterology
Background:
- Resistant starch type 3 (RS-3) is a highly indigestible form of starch that reaches the colon intact.
- Gut microbes play a crucial role in fermenting undigested carbohydrates.
- Understanding the degradation of RS-3 by specific microbes is important for gut health and nutrition.
Purpose of the Study:
- To investigate the ability of Ruminococcus bromii and Bifidobacterium adolescentis to degrade intrinsic RS-3.
- To compare the degradation of RS-3 with different physico-chemical characteristics (crystal type, chain length).
- To explore the microbial mechanisms involved in RS-3 fermentation.
Main Methods:
- Incubation of intrinsic RS-3 (A-type and B-type) with R. bromii and B. adolescentis.
- Quantification of remaining glucose, malto-oligosaccharides, and RS-3 over time.
- Visualization of starch degradation using Scanning Electron Microscopy (SEM).
- Comparison with the degradation of granular maize and potato starch.
Main Results:
- R. bromii degraded all tested RS-3 substrates effectively, producing maltose and glucose.
- B. adolescentis failed to degrade B-type RS-3 and showed limited degradation of A-type RS-3.
- SEM revealed distinct degradation patterns of RS-3 by the two microbes.
- B. adolescentis readily fermented granular maize and potato starch.
Conclusions:
- Efficient degradation of intrinsic RS-3 requires specific microbial enzyme systems, as exemplified by R. bromii.
- The physico-chemical properties of RS-3 influence its fermentability by gut bacteria.
- Microbial composition and enzymatic capabilities are critical for harnessing the benefits of resistant starch.
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