8.2.3. Chemicals, Enzymes and other Bioactive Molecules

Microbes are also used for commercial and industrial production of certain chemicals like organic acids, alcohols and enzymes. Examples of acid producers are Aspergillus niger (a fungus) of citric acid, Acetobacter aceti (a bacterium) of acetic acid; Clostridium butylicum (a bacterium) of butyric acid and Lactobacillus (a bacterium) of lactic acid.

Microorganisms play a crucial role in manufacturing a variety of essential chemicals. Different types of microbes are used based on the specific chemical that needs to be produced. For instance:

• Aspergillus niger is a fungus renowned for producing citric acid, used widely in food and beverages as a flavoring and preservative.
• Acetobacter aceti is a bacterium that helps convert alcohol into acetic acid, commonly found in vinegar.
• Clostridium butylicum produces butyric acid, which has applications in food processing.
• Lactobacillus produces lactic acid, essential in dairy products like yogurt and some fermented foods.

Think of microbes as tiny factories. Just like different factories specialize in making specific products, such as a car factory or a furniture factory, various microbes specialize in producing specific chemicals. For example, when you enjoy a tangy soda, it might have citric acid produced by fungi like Aspergillus niger, similar to how a car has unique parts made by specific machines.

Yeast (Saccharomyces cerevisiae) is used for commercial production of ethanol. Microbes are also used for production of enzymes. Lipases are used in detergent formulations and are helpful in removing oily stains from the laundry.

Microorganisms also synthesize various enzymes that have significant commercial applications.

• Saccharomyces cerevisiae, or baker's yeast, not only helps in making bread but is also utilized for producing ethanol, an important alcohol used in beverages and as a fuel.
• Enzymes like lipases are derived from microbes and are crucial in the formulation of detergents, where they act on fats in stains, breaking them down and allowing for easier cleaning.

Consider yeast as a sugar-transforming magician: when it gets sugar, it not only creates delicious bread but also brews alcohol like a talented chef. Similarly, think of lipases in detergent like a specialized cleaner that knows exactly how to tackle tricky grease stains on your clothes!

You must have noticed that bottled fruit juices bought from the market are clearer as compared to those made at home. This is because the bottled juices are clarified by the use of pectinases and proteases.

In commercial juice production, the use of enzymes like pectinases and proteases is common to improve clarity and shelf life.

• Pectinases break down pectin, a component in plant cell walls that can cloud juices, resulting in a clearer and more appealing product.
• Proteases break down proteins that could lead to cloudiness or sediment in juice, allowing for a smoother final product.

If you've ever tried to make juice at home, you might have noticed that it can be pulpy and thick, whereas commercial juices are often crystal clear. Imagine pectinases and proteases as clear-out agents, like skilled housekeepers that tidy up your juice by removing all the unnecessary clutter!

Streptokinase produced by the bacterium Streptococcus and modified by genetic engineering is used as a ‘clot buster’ for removing clots from the blood vessels of patients who have undergone myocardial infarction leading to heart attack.

Certain microbial products are of great importance in medicine. For example, Streptokinase is an enzyme derived from Streptococcus bacteria, which can dissolve blood clots in medical emergencies, particularly in heart attack cases.

• This enzyme works quickly to break down the clot, restoring blood flow and potentially saving lives. Genetic engineering techniques allow for scaling up its production safely for use in hospitals.

Think of Streptokinase as an emergency rescue team for clogged roads. Just like a combination of skilled personnel and machinery works together to clear an obstructed route after an accident, Streptokinase quickly clears blood clots, opening up pathways for blood to flow freely again.

Another bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Trichoderma polysporum. Statins produced by the yeast Monascus purpureus have been commercialised as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.

Microbes are also sources of bioactive compounds with therapeutic effects.

• Cyclosporin A, derived from the fungus Trichoderma polysporum, suppresses the immune system responses, which is crucial for patients receiving organ transplants to prevent rejection.
• Statins, produced by yeast, are used to manage cholesterol levels in the blood, helping reduce the risk of heart disease by inhibiting cholesterol production in the liver.

Consider cyclosporin A as a gentle bouncer at a club, ensuring that only authorized guests (transplanted organs) are allowed to stay without interference. On the other hand, think of statins like a traffic cop, managing and controlling the flow of cholesterol in the bloodstream to ensure everything runs smoothly and safely.

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