The adopted bacterium - Lactobacillus casei

Lactobacillus casei are Gram-positive, facultatively anaerobic, non-motile and non-spore-forming, rod-shaped (cell size range = 0.7-1.1 x 2.0-4.0 micrometer).

Lactobacillus casei is found in different parts of the body, especially in the mouth and intestines. It therefore has a high tolerance for pH (acidity) and a wide range of temperatures. But pH and temperature are not the only differences between mouth and intestines. The biggest difference is the lack of oxygen in the intestines ( anaerobic ), while the mouth is full of oxygen ( aerobic ). L. casei is a facultative anaerobic organism, meaning that it can survive with or without oxygen. This is useful, since L. casei has all kinds of essential tasks in the anaerobic intestines.

One thing L. casei does is regulate the immune system of the intestines. The bacteria attach to the intestinal wall where they stimulate the intestinal lymph tissue that reinforces the body’s immune response. They also help keep some of the more harmful microorganisms under control. If you don’t have enough of the good bacteria, things can get out of balance and cause trouble. L. casei also protects the body against pathogens by competing with them for food and space. In addition, the bacteria reduce the growth of pathogens by lowering the pH with the acids they produce. They also make bacteriocins: antimicrobial proteins which kill pathogens.

.L. casei are a remarkably adaptive species, and may be isolated from raw and fermented dairy products, fresh and fermented plant products, and the reproductive and intestinal tracts of humans and other animals. Industrially, L. casei have application as human probiotics (health-promoting live culture), as acid-producing starter cultures for milk fermentation, and as specialty cultures for the intensification and acceleration of flavor development in certain bacterial-ripened cheese varieties.

Because L. casei is so important to health it is often used as a probiotic. Unlike the harmful bacteria that make you sick, probiotics like L. casei are beneficial to your digestive system. Probiotics are microbes which can have a beneficial effect on health if ingested in sufficient amounts. Actually, your body depends on them. Without them, it’s much harder to digest food and absorb important nutrients. L. casei can reduce the chance of intestinal infection and improve bowel movement. When you don’t have enough of the good bacteria, adding more L. Casei to your diet can help regulate your digestive system. Probiotic supplements containing L. Casei are used to prevent or treat diarrhea. This includes infectious diarrhea, traveler’s diarrhea, and antibiotic-associated diarrhea.

The most common application of L. casei is industrial, specifically for dairy production. Lactobacillus casei is typically the dominant species of nonstarter lactic acid bacteria (i.e. contaminant bacteria[1]) present in ripening cheddar cheese, and, recently, the complete genome sequence of L. casei ATCC 334 has become available. Lactobacillus casei ATCC 393 strain has been reported to have beneficial effects for cholesterol removal, reduction of the risk of osteoporosis, activity against cancer cell proliferation, beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects, survived the passage through the GI tract in a rat model and potential regulates intestinal microbiota. In addition L. casei ATCC 393 is a strain with satisfying technological characteristics and therefore has numerous applications in the production of food products such as cheese, sausages, fermented milks and yogurts. L. casei is also the dominant species in naturally fermented Sicilian green olives.

This slide is a smear of the gram-positive bacteria Lactobacillus Casei. This bacteria is a lactic acid producer that is used for dairy production.

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