Which of the following microorganism is used for commercial production of dextran?
1. Baciluspolymyxa
2. Streptomyces olivaceus
3. Leuconostocmesenteroides
4. Bacillus thuringiensis

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Detailed Explanation:

Correct Answer: 3. Leuconostoc mesenteroides

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What is Dextran?

Dextran is a complex polysaccharide composed of glucose molecules linked together, and it has wide applications in the food, pharmaceutical, and biotechnology industries. It is especially known for its ability to improve the texture of certain foods and as a stabilizer in pharmaceutical formulations. Additionally, dextran is used as an anticoagulant in medical treatments and as a plasma volume expander in medical applications.

Microorganisms Used for Dextran Production:

Several microorganisms are capable of producing dextran, but Leuconostoc mesenteroides stands out as the primary microbe used in the commercial production of dextran. Let’s explore the role of various microorganisms:

1. Leuconostoc mesenteroides:

   • This bacterium is the most commonly used microorganism for the commercial production of dextran. It belongs to the group of lactic acid bacteria and is known for its ability to produce dextran from sucrose via fermentation. It produces dextran by utilizing sucrose and converting it into a polymer form, which has various industrial applications. Leuconostoc mesenteroides is preferred for its efficiency and consistency in producing high-quality dextran.

2. Bacillus polymyxa:

   • Bacillus polymyxa is not typically used for dextran production. While Bacillus species are well known for producing a variety of enzymes and compounds, this specific strain is not involved in commercial dextran production.

3. Streptomyces olivaceus:

   • Streptomyces olivaceus is not a dextran producer either. This bacterium is more commonly associated with the production of antibiotics like olivamycin, but not polysaccharides like dextran.

4. Bacillus thuringiensis:

   • Bacillus thuringiensis is primarily known for its use as a biopesticide. It produces insecticidal proteins that are toxic to certain insects, but it does not produce dextran or similar polysaccharides.

Why Leuconostoc mesenteroides is the Preferred Microorganism:

Leuconostoc mesenteroides is preferred in the industrial production of dextran due to its high efficiency in converting sucrose into dextran. The bacterium produces dextran in the presence of high sucrose concentrations, and the polysaccharide it produces has favorable properties for various commercial applications. The process is relatively simple, involving fermentation, and can be scaled up for large-scale production.

Applications of Dextran:

• Food Industry: Used as a stabilizer, emulsifier, and texturizing agent in products like salad dressings, sauces, and ice creams.

• Pharmaceuticals: Used as a plasma expander in medical treatments, especially during surgeries or traumatic injuries.

• Biotechnology: Employed in the separation of proteins and in the purification of biologics.

Conclusion:

Among the options provided, Leuconostoc mesenteroides is the microorganism most commonly used for the commercial production of dextran. Its ability to efficiently produce dextran from sucrose makes it an important microorganism in both food and pharmaceutical industries. Understanding its role in industrial production highlights its significance in biotechnology and medical applications.