Keywords

1. Exopolysaccharides
2. Lactic Acid Bacteria
3. Tempeh Benefits
4. Anti-Adhesion
5. Enterotoxigenic Escherichia coli

In an era where the prevalence of antibiotic resistance is escalating, finding alternative approaches to combat pathogenic organisms is becoming of utmost importance. The traditional Indonesian soy food, known as tempeh, might offer an innovative solution—thanks to a groundbreaking study focusing on an array of favorable microorganisms that naturally occur within it. Researchers from renowned institutions have recently unravelled a mechanism intrinsic to tempeh’s microflora that potently counters a notorious diarrhea-causing perpetrator: enterotoxigenic Escherichia coli (ETEC).

According to the study published in the ‘Carbohydrate Polymers’ journal on March 15, 2024, investigators from the Laboratory of Food Chemistry, Wageningen University & Research, in collaboration with Atma Jaya Catholic University of Indonesia and NutriLeads B.V., have identified certain strains of lactic acid bacteria (LAB) that synthesize exopolysaccharides (EPS) with significant anti-adhesion activity against ETEC—a much-needed bioactivity in fighting infections without relying on conventional antibiotics.

DOI: 10.1016/j.carbpol.2023.121700

The research, led by Pramudito Theodorus Eko, Krishna Desai, Camiel Voigt, Eddy J. Smid, and Henk A. Schols, pinpoints how LABs from tempeh, such as Pediococcus pentosaceus TL and various Leuconostoc species, secrete sizable quantities of dextran and levan—two types of EPS known for their health benefits. Dextran is an α-1,6 linked glucan, while levan is a β-2,6 linked fructan, both renowned for their prebiotic properties.

The Study’s Highlights

Conducted with rigorous scientific methodologies, the study involved isolating LABs from sources related to tempeh, using state-of-the-art approaches to identify the bacteria and elucidate the structure of the EPS they produced. Subsequently, the team evaluated the bioactivity of these EPS molecules against ETEC, discovering their capacity to adhere to ETEC cells and preemptively block their auto-aggregation—a critical step in ETEC’s pathogenesis mechanism.

In particular, EPS-PpTL, EPS-LmWA, and EPS-LmWN exhibited pronounced bioactivity towards pig-associated ETEC K88, whereas EPS-LcTR showed higher efficacy against the human-associated ETEC strain H10407. These observations mark the first recorded instance wherein dextran and levan demonstrate this form of bioactivity.

This work underlines the significance of the LABs present in tempeh and their invaluable role in synthesizing bioactive molecules with the potential of serving as natural supplements to enhance health or even as biotherapeutics. Among the LAB strains identified and their associated EPS bioactivities were:

1. Pediococcus pentosaceus TL
2. Leuconostoc mesenteroides WA
3. Leuconostoc mesenteroides WN
4. Leuconostoc citreum TR

Their EPS products ranged from high-molecular-weight dextrans to versatile levans, with potent bioactivity exhibited by each.

Implications and Future Applications

The discovery of these anti-adhesion EPS molecules inaugurates a new vantage point in preventive strategies and possible treatments against ETEC-related diarrhea, which remains a leading cause of mortality in developing countries, especially among the pediatric population. The potential applications transcending mere human benefit, extending to animal husbandry, are also part of the broader impacts of this research—particularly relevant for swine, which are frequently affected by ETEC.

Besides their direct impact on health, these EPS have other attractive qualities, such as being produced from a sustainable and natural food source—soybeans in the form of tempeh. This taps into the global trend towards eco-friendly and renewable solutions in various industries.

The study also emphasizes the utility of tempeh beyond its nutritional value, revealing that this fermented food could be a reservoir of potentially beneficial LABs and their metabolic products.

Recommendations and Considerations

Going forward, it is crucial to evaluate the safety, efficacy, and production scalability of these EPS in a broader spectrum of environments and organisms. Additionally, socio-economic factors playing into the industrial feasibility of utilizing tempeh-derived LABs on a mass scale must be thoroughly considered.

This research sets the stage for more in-depth exploration into the pharmacological potential of exopolysaccharides beyond gut health, including immunomodulation and cancer therapy, given the known beneficial effects of prebiotics on overall health.

Copyright Notice

The study and its outcomes are protected by copyright laws, with exclusive rights held by Elsevier Ltd. and the contributing researchers, ensuring the findings are disseminated with proper credit to the originators of the work.

References

1. Pramudito, T. E., Desai, K. K., Voigt, C. C., Smid, E. J., & Schols, H. A. (2024). Dextran and levan exopolysaccharides from tempeh-associated lactic acid bacteria with bioactivity against enterotoxigenic Escherichia coli (ETEC). Carbohydrate Polymers, 328, 121700. https://doi.org/10.1016/j.carbpol.2023.121700

2. Patel, S., & Goyal, A. (2012). The current trends and future perspectives of prebiotics research: a review. 3 Biotech, 2(2), 115–125. https://doi.org/10.1007/s13205-012-0044-5

3. Gibson, G. R., & Roberfroid, M. B. (1995). Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics. Journal of Nutrition, 125(6), 1401-1412. https://doi.org/10.1093/jn/125.6.1401

4. Lebeer, S., Vanderleyden, J., & De Keersmaecker, S. C. J. (2008). Genes and molecules of lactobacilli supporting probiotic action. Microbiology and Molecular Biology Reviews, 72(4), 728–764. https://doi.org/10.1128/MMBR.00017-08

5. Byndloss, M. X., & Bäumler, A. J. (2018). The germ-organ theory of non-communicable diseases. Nature Reviews Microbiology, 16(2), 103-110. https://doi.org/10.1038/nrmicro.2017.158

Declaration of Competing Interest

The authors have disclosed no competing interests in relation to this study and its publication. The study was conducted with the highest standards of academic integrity and transparency.