Lactobacillus casei It is a species of bacteria that is part of the group called lactic bacteria. It was discovered by Eli Metchnikoff in the year 1900, who described the role of this microorganism in intestinal digestion, which opened the way for this bacterium to be considered a probiotic. That is, it is capable of exerting health benefits, beyond the inherent basic nutrition.
Lactobacillus casei It belongs to the group of lactic acid bacteria, because it is useful in the fermentation of products that contain milk, such as yogurt, kefir, zeer wash and a variety of cheeses such as Parmesan and Manchego, among others..
From there it comes that in 1919 it was designated the name "casei", whose nomenclature is mainly related to the word cheese, that is, to the Latin word "caseus ", which means cheese, and also with casein, which is the main protein in milk.
With the techniques of molecular biology it has been possible to elucidate that this microorganism is really a group of species, which can even be subdivided into sub-species.
These species, although genetically similar, have dissimilar characteristics. For example, there is variation in the ability to ferment carbohydrates and in optimal temperature growth.
Lactobacillus casei can be used alone or in association with other bacteria of the same group, in order to provide different organoleptic properties to the foods in which they are included.
Lactobacillus casei inhabits the oral and intestinal mucosa of humans. It is also widely distributed in the environment, in fermented vegetables, meat and milk..
They are generally heterofermentative, which means that they not only produce lactic acid, but also C0two, small amounts of ethanol and other aromatic substances.
In relation to the optimal growth temperature is at 37 ° C, therefore they are mesophiles, although some subspecies can resist high temperatures for a certain time.
They are considered aerotolerant anaerobes, that is, they grow perfectly under anaerobic conditions (without oxygen), but they can grow in the presence of it. In the same way, they will obtain ATP through the fermentation of carbohydrates..
Its ability to resist oxygen will depend on being able to eliminate or degrade the two highly toxic products that are derived from the use of oxygen, such as hydrogen peroxide and superoxide ion. This is possible with the production of enzymes such as catalase and superoxide dismutase..
They resist bile acids and salts, being able to live in a range from pH 3 to pH7. These characteristics are necessary to be able to inhabit the intestine. Something important is that to exert their probiotic action in the intestine they must be in sufficient and viable quantities to achieve the desired benefits.
Among the main biochemical characteristics of some of the subspecies of L. casei you have:
It grows at 10-40ºC and ferments Ribose, Sucrose and D-turanose.
It grows at 10-40ºC and ferments a wide variety of carbohydrates.
Optimal growth at 10-37ºC, but it is able to resist temperatures of 70ºC for 40 min. Ferment very few carbohydrates.
It grows at 15-45ºC and ferments rhamnosa
Members of this group lack porphyrins and cytochromes, do not perform oxidative phosphorylation, and the energy they require is obtained by phosphorylation at the substrate level..
Most lactic acid bacteria can obtain energy only from the metabolism of carbohydrates and related compounds, for this reason their habitat must contain them.
The biosynthetic capacity of Lactobacillus casei it is very limited. Their nutritional requirements are complex, because to grow they need the presence of vitamins, purines and pyrimidines.
They also require lipoic acid for their growth, as they use it to form Acetyl Coenzyme A from pyruvate..
Very rarely, L. casei has been implicated as a causal agent of any disease.
Very few cases have been reported where it is attributed to have caused endocarditis, but whose source has never been food.
The Lactobacillus casei they are characterized by being Gram positive rods, immobile and do not form spores.
They are smaller than other species, such as L. bulgarícus, L. acidophilus and L. helveticus, although some authors describe it as bacilli of great variability in shape, size and grouping with a great tendency to form chains.
Lactobacillus casei provides a variety of benefits discussed below:
Its presence in the intestine is healthy, since in healthy individuals it is capable of maintaining the balance of the intestinal microbiota.
In patients with diarrhea caused by prolonged antibiotic therapies or gastrointestinal infections by enteropathogenic bacteria, they are capable of restoring the intestinal microbiota and fighting the infection..
Especially it has been seen that it is very useful in infections by Clostridium difficile in the intestine and by rotavirus.
It is also useful for the prevention of colon cancer by reducing enzymes that are directly related to this type of cancer.
The enzymes involved are glucuronidase, nitroreductase, and glycocholic acidhydrolase. These enzymes in high concentrations increase the rate of conversion of procarcinogenic to carcinogenic cells in the intestine, increasing the risk of colon cancer..
The consumption of yogurt and fermented milk with L. casei It is recommended for people who do not have lactase in their body, since in these foods the lactose is more digested and it is easier for them to tolerate it.
Increases innate immune response promoting the immunoenhancing capacity of nonspecific immune system cells, including macrophages.
Increases the acquired immune response by increasing B lymphocytes, production of tumor necrosis factor, interferon gamma e interleukin 12. Also regulatory cytokines (IL-4, IL-10).
It also improves both systemic and mucosal immunity. In the latter it increases secretory immunoglobulins A.
That is how L. casei maintains homeostasis in the mucosa, stimulating the immune system in various permanent and effective surveillance mechanisms. One of these mechanisms is the stimulation of the secretory immune system through IgA antibodies..
Likewise, L. casei, together with the rest of the protective microbiota, prevent the invasion and colonization of pathogenic microorganisms by competing for receptors and / or metabolic substrates..
The mechanism is not known but it has been seen that people who consume products containing L. casei do not increase your plasma cholesterol levels.
Therefore, it is beneficial to prevent cardiovascular diseases such as atherosclerosis.
Consumption of fermented foods with L. casei improves tolerance of strong combined antibiotic treatment in this pathology, as it helps the intestinal microbiota not lose its balance and thus avoid diarrhea caused by antibiotic therapies.