Lactobacillus delbrueckii subsp. bulgaricus facts for kids
Quick facts for kids Lactobacillus Bulgaricus subsp. ' |
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| Lactobacillus Bulgaricus from a sample of yogurt. Numbered ticks are 11 μm apart. | |
Scientific classification  |
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| Domain: | Bacteria |
| Phylum: | Firmicutes |
| Class: | Bacilli |
| Order: | Lactobacillales |
| Family: | Lactobacillaceae |
| Genus: | Lactobacillus |
| Species: |
L. Bulgaricus
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| Trinomial name | |
| Lactobacillus Bulgaricus subsp. ' (Orla-Jensen 1919) Rogosa & Hansen 1971 Weiss et al. 1984
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Lactobacillus bulgaricus (scientific name: Lactobacillus delbrueckii subsp. bulgaricus) is a type of bacterium that is very important for making food. It is the main ingredient used to turn milk into yogurt. It also helps make certain types of cheese.
This bacterium is known as a probiotic, which means it is a "friendly" germ that can be good for your health. It eats the sugars found in milk and turns them into lactic acid. This process is called fermentation. Because it helps make healthy foods, it is grown and used in many countries around the world.
Contents
What is Lactobacillus bulgaricus?
This bacterium is a microscopic organism. Under a microscope, it looks like a long rod. It does not have legs or flagella, so it cannot move around on its own.
Living conditions
To grow well, Lactobacillus bulgaricus needs a specific environment:
- Temperature: It loves warmth. It grows best at temperatures between 40°C and 44°C (104–111°F).
- Acidity: It prefers an acidic environment with a low pH (around 4.6 to 5.4).
- No Oxygen: It is an anaerobe, meaning it lives and grows best in places without oxygen.
It finds all these conditions inside warm milk. As it eats the milk sugar, it produces acid, which keeps the environment perfect for itself and stops bad bacteria from growing.
Where is it found?
This bacterium was first found in the Bulgarian region. It lives naturally in the digestive systems of mammals in that area. It can also be found on plants. For example, one special type called GLB44 is found on the leaves of the snowdrop flower (Galanthus nivalis) in Bulgaria.
History of discovery
The story of this bacterium goes back more than 100 years.
The young scientist
In 1905, a Bulgarian doctor named Stamen Grigorov was studying yogurt. He looked at samples under a microscope and discovered the rod-shaped bacteria that caused the milk to ferment. He was the first person to identify it.
The secret to long life?
A famous scientist named Ilya Metchnikoff, who worked at the Pasteur Institute in Paris, became very interested in Grigorov's discovery. Metchnikoff noticed that people in Bulgarian villages lived very long lives. He wondered if their diet had something to do with it.
Metchnikoff believed that eating yogurt every day helped these people live longer. He thought the "good" bacteria in yogurt fought against "bad" bacteria in the intestines that produced toxins. Although later studies showed the bacteria don't stay in the human body forever, his ideas started the modern study of probiotics.
National symbol
Because of its importance to the country's history and food, this bacterium is very famous in Bulgaria. In 2012, it was even declared the national microbe of India, showing how important it is for making dairy products like dahi (curd) around the world.
How it is used
The most common job for Lactobacillus bulgaricus is making yogurt. It usually works with a partner bacterium called Streptococcus thermophilus.
The yogurt team
These two bacteria help each other grow in a process called symbiosis:
- Lactobacillus bulgaricus breaks down milk proteins to make amino acids, which the other bacterium needs.
- Streptococcus thermophilus makes other nutrients that help the Lactobacillus grow.
Together, they turn milk into yogurt. They produce lactic acid, which does two things:
- It gives yogurt its sour, tart taste.
- It makes the milk proteins clump together (coagulate), which makes the yogurt thick.
This process also creates natural preservatives, so the yogurt stays fresh longer than plain milk.
Economic importance
Because so many people eat yogurt and cheese, this bacterium is very valuable. Countries like Japan, the United States, and nations in the European Union import large amounts of it to produce food.
Scientific research
Scientists are still studying this bacterium to learn more about how it works and how it can help us.
Helping with milk allergies
Some children and infants have a cow's milk protein allergy. This means their bodies react badly to the proteins in milk. In 2012, a study looked at whether fermenting milk with Lactobacillus bulgaricus could help.
The researchers found that the fermentation process changed some of the milk proteins. This made them less likely to cause an allergic reaction in some cases. However, it is important to always talk to a doctor about food allergies.
Surviving the cold
Bacteria are living things, and extreme cold can hurt them. Scientists want to keep these bacteria alive for a long time so they can be shipped to factories to make yogurt. The most common method is freeze-drying (removing water while frozen).
However, freezing can damage the bacteria's outer shell (membrane). Studies have shown that adding certain ingredients, like salt or natural sugars (sorbitol), can act like a shield. This helps the bacteria survive the freezing process so they can wake up and get to work when they are put into warm milk.
