Lactobacillus alimentarius

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1. Classification

Higher order taxa

Bacteria; Bacillota; Bacilli; Lactobacillales; Lactobacillaceae (1)

Species

Companilactobacillus (1)

2. Introduction

Description & Significance

Companilactobacillus alimentarius (also known as Lactobacillus alimentarius) is a lactic acid bacteria, which belongs to the family Lactobacillaceae. They are one of the most abundant groups of bacteria that are associated with humans, due to their use in fermentation to improve the taste and texture of food products. L. Alimentarius was discovered during an investigation on fish products, where it was identified as a spoilage organism in marinated herring (2). Although details relating to the genome and metabolism of L. alimentarius are unknown, it possesses a wide range of antimicrobial capabilities against Gram-positive and Gram-negative food-borne pathogens and several yeasts (3). Its heat-resistant properties and ability to withstand a broad range of pH allow it to be used as a natural food preservative, particularly for meats and dairy products (3). L. alimentarius is predominantly used in food spoilage prevention and safety in the food production industry.

3. Genome structure

The full genome of L. alimentarius is 2.34 Mbp, and the percent G+C content of DNA is 35.4%. (4). L. alimentarius has nine “signature genes” that are unique to the lineage, but they have not been described in detail (4). 213 strains of Lactobacilli have had their genomes analyzed: among these, the core genome consists of 73 genes, with the majority of them responsible for encoding essential proteins that are necessary for cell growth and replication (5). Lactobacilli also exhibit genes and molecules that support their probiotic function (7) Specifically, they encode genes involved in carbohydrate and protein metabolism, adherence mechanisms, and bacteriocin secretion (7). A large majority of the genome consists of a variety of phage and plasmid sequences. (5).

4. Cell Structure/Morphology

L. alimentarius are Gram-positive, motile, and non-spore-forming, bacilli (8)(6). The length of L. alimentarius is dependent on the growth environment. The presence of citric acid, gluconic acid, or their combination promotes cellular elongation of L. alimentarius, but the bacterium does not show cellular elongation in the presence of NaCl (salt) (9), suggesting two different adaptation mechanisms by which cells respond to these substances (9). The cell wall of Lactobacilli consists of a thick, 20-100 nm, multi-layered peptidoglycan layer with teichoic acids, S-layer proteins, and other types of cell surface proteins that aid in structural integrity and protection (7).

5. Metabolic Processes

L. Alimentarius are facultative hetero-fermentative bacteria (9) that ferment glucose and produce lactic acid, ethanol, and carbon dioxide as major byproducts (11). Growth of L. alimentarius occurs between 15°C and 37°C, and pentoses, hexoses, and disaccharides are primarily used as carbon sources (4). L. alimentarius can produce high concentrations of lactic acid in food products to reduce the pH enough to cause an antibacterial effect (12). L. Alimentarius contains many probiotic properties such as nitrite degradation, cholesterol removal, and antioxidant activity (13). The species within the genus Lactobacillus are predominantly oxygen-tolerant anaerobes, yet several strains can use oxygen in flavin oxidase-mediated reactions (14). Lactobacilli can degrade indigestible polysaccharides and protein, catabolize amines, and transform undesirable food ingredients into flavor substances (15). These flavor substances include organic acids, alcohols, ketones, and esters, which depend on the metabolic pathways (15). In the manufacturing of fermented foods and flavor development, the three main metabolic processes Lactobacilli partake in include glycolysis (sugar degradation), proteolysis (protein degradation), and lipolysis (fat degradation).

6. Ecology

L. alimentarius is mostly found in nutrient-rich habitats (16), such as fermented or spoiled foods and animal feed. Animal feed includes the body of invertebrate and vertebrate animals, as well as the surface of plants and soil. L. alimentarius is restricted by specific growth conditions, such as temperature and pH. Optimal growth temperatures range from 30-40 degrees Celsius and optimal pH ranges from 5.5-6.2 (8). Species of the Lactobacillus genus have been found throughout human bodies, specifically in the mouth, gastrointestinal tract, and female genital tract (17). However, existing research has not provided evidence that L. alimentarius inhabits the human body.

7. Pathology

L. alimentarius has a very limited pathogenic potential and the research on this topic is limited. Many species of the Lactobacilli genus are considered to have beneficial effects on human health, often used in probiotics; however, occasionally they can cause infections, including endocarditis, bacteremia, neonatal meningitis, dental caries, pleuropneumonia, and intra-abdominal abscesses (18). Serious infections due to Lactobacilli, such as primary bacteremia and endocarditis, have been observed in elderly individuals and immunocompromised patients, particularly those who have undergone organ transplantation (19). Endocarditis stands out as the most prevalent clinical condition associated with these infections and poses a significant risk to mortality rates (19). Other infections associated with Lactobacilli include intra-abdominal abscesses, meningitis, oral infections, conjunctivitis, bacteremia, and pleuropneumonia (19).

8. Current Research

Notable studies in recent years have shown that L. alimentarius could be beneficial to human gut health due to its role in fermented food. Although there is evidence that associates Lactobacilli probiotics with gut health, further research is being done to understand the mechanism behind its probiotic effects (20). Because the effects may vary from person to person, more clarification on the specific processes by which they influence health is needed for individuals to know how much benefit or value difference they can expect to gain when Lactobacillus probiotics are consumed. Researchers have also isolated Lactobacilli to evaluate their antagonistic effects against various pathogens such as Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa (21). It has been shown that Lactobacilli can eliminate pathogens through microbial competition, which can now be incorporated into various foods and pharmaceutical products (21).

9. References

[1] [Taxonomy. Taxonomy Browser (Companilactobacillus Alimentarius). https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1602]

[2] [Lyhs, U., Korkeala, H., Vandamme, P., & Björkroth, J. (2001). Lactobacillus alimentarius: a specific spoilage organism in marinated herring. International journal of food microbiology, 64(3), 355–360. https://doi.org/10.1016/s0168-1605(00)00486-4]

[3] [Hu, Y., Liu, X., Shan, C., Xia, X., Wang, Y., Dong, M., & Zhou, J. (2017). Novel bacteriocin produced by Lactobacillus alimentarius FM-MM 4 from a traditional Chinese fermented meat Nanx Wudl: Purification, identification and antimicrobial characteristics. Food Control, 77, 290–297. https://doi.org/10.1016/j.foodcont.2017.02.007]

[4] [Zheng, Jinshui, et al. “A Taxonomic Note on the Genus Lactobacillus: Description of 23 Novel Genera, Emended Description of the Genus Lactobacillus Beijerinck 1901, and Union of Lactobacillaceae and Leuconostocaceae.” International Journal of Systematic and Evolutionary Microbiology, vol. 70, no. 4, 1 Apr. 2020, pp. 2782–2858, https://doi.org/10.1099/ijsem.0.004107. Accessed 11 Aug. 2020.]

[5] [Sun, Z., Harris, H., McCann, A. et al. Expanding the biotechnology potential of lactobacilli through comparative genomics of 213 strains and associated genera. Nat Commun 6, 8322 (2015). https://doi.org/10.1038/ncomms9322]

[6] [​​Cai, Yimin, et al. “Lactobacillus Paralimentarius Sp. Nov., Isolated from Sourdough.” International Journal of Systematic and Evolutionary Microbiology, vol. 49, no. 4, 1 Oct. 1999, pp. 1451–1455, https://doi.org/10.1099/00207713-49-4-1451. Accessed 13 Mar. 2023.]

[7] [Lebeer, S., Vanderleyden, J., & De Keersmaecker, S. C. J. (2008b). 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]

[8] [Salvetti, E., Torriani, S., & Felis, G. E. (2012). The Genus Lactobacillus: A Taxonomic Update. Probiotics and antimicrobial proteins, 4(4), 217–226. https://doi.org/10.1007/s12602-012-9117-8]

[9] [Bintsis T. (2018). Lactic acid bacteria as starter cultures: An update in their metabolism and genetics. AIMS Microbiology, 4(4), 665–684. https://doi.org/10.3934/microbiol.2018.4.665]

[10] [Lemay, M., Rodrigue, N., Gariépy, C., & Saucier, L. (2000). Adaptation of Lactobacillus alimentarius to environmental stresses. International Journal of Food Microbiology 55(1-3), 249-253. https://doi.org/10.1016/S0168-1605(00)00181-1.]

[11] [Ibrahim, S. A. (2016). Lactic Acid Bacteria: Lactobacillus spp.: Other Species. In Elsevier eBooks. https://doi.org/10.1016/b978-0-08-100596-5.00857-x]

[12] [Juven, B., Barefoot, S. F., Pierson, M., Mccaskill, L., Smith, B. (1998) Growth and Survival of Listeria monocytogenes in Vacuum-Packaged Ground Beef Inoculated with Lactobacillus alimentarius FloraCarn L-2, Journal of Food Protection 61(5), 551-556. https://doi.org/10.4315/0362-028X-61.5.551]

[13] [Tang, W., Hu, W., Wang, J., Wang, J., & Wang, Y. (2016). Wei sheng wu xue bao = Acta microbiologica Sinica, 56(6), 932–942. https://pubmed.ncbi.nlm.nih.gov/29727550/]

[14] [Zotta, T., et al. “Aerobic Metabolism in the GenusLactobacillus: Impact on Stress Response and Potential Applications in the Food Industry.” Journal of Applied Microbiology, vol. 122, no. 4, 16 Feb. 2017, pp. 857–869, https://doi.org/10.1111/jam.13399.]

[15] [Wang, Y., Wu, J., Lv, M., Shao, Z., Hungwe, M., Wang, J., Bai, X., Xie, J., Wang, Y., & Geng, W. (2021). Metabolism characteristics of lactic acid bacteria and the expanding applications in the food industry. Frontiers in Bioengineering and Biotechnology, 9. https://doi.org/10.3389/fbioe.2021.612285]

[16] [Duar, R. M., Lin, X. B., Zheng, J., Martino, M. E., Grenier, T., Pérez-Muñoz, M. E., Leulier, F., Gänzle, M., & Walter, J. (2017). Lifestyles in transition: evolution and natural history of the genus Lactobacillus. FEMS microbiology reviews, 41(Supp_1), S27–S48. https://doi.org/10.1093/femsre/fux030]

[17] [Goldin, Barry R., et al. “Survival Of Lactobacillus Species (Strain GG) in Human Gastrointestinal Tract.” Digestive Diseases and Sciences, vol. 37, no. 1, Jan. 1992, pp. 121–128, link.springer.com/article/10.1007%2FBF01308354, https://doi.org/10.1007/bf01308354.]

[18] [Rossi, F., Amadoro, C., & Colavita, G. (2019). Members of the Lactobacillus Genus Complex (LGC) as Opportunistic Pathogens: A Review. Microorganisms, 7(5), 126. https://doi.org/10.3390/microorganisms7050126]

[19] [Goudoever V (2022) Pathogenesis and Functions of Lactobacillus as Probiotic. J Prob Health. 10:279.]

[20] [Dempsey, E., & Corr, S. C. (2022). Lactobacillus spp. for Gastrointestinal Health: Current and Future Perspectives. Frontiers in Immunology, 13, 840245. https://doi.org/10.3389/fimmu.2022.840245]

[21] [Karami, S., Roayaei, M., Hamzavi, H., Bahmani, M., Hassanzad-Azar, H., Leila, M., & Rafieian-Kopaei, M. (2017). Isolation and identification of probiotic Lactobacillus from local dairy and evaluating their antagonistic effect on pathogens. International Journal of Pharmaceutical Investigation, 7(3), 137–141. https://doi.org/10.4103/jphi.JPHI_8_17]

Edited by Nicole Agwu, Kimberly Chen, Nathalie Prebich, Kitty Xia, & Kathleen Wei students of Jennifer Bhatnagar for BI 311 General Microbiology, 2020, Boston University.

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