Basic Knowledge of Microbiology

Biomass to Biogas Using Cascade Technology

Solid Wastes to Clean Energy Using Cascade technology

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IMPORTANCE OF MICROORGANISMS TO HUMANS

We live at the center of a microbial universe. Every breath we take brings thousands of microorganisms into our body. A single pinch of rich soil may contain a billion microorganisms.

The great majority of microorganisms benefit humans by recycling the elements of life, producing many foods and industrial products, and serving as research tools. Other microorganisms are the agents of disease. We here briefly survey some examples of how microorganisms influence the quality of our lives.

Over the centuries, social customs and traditions have led people to accept and enjoy certain foods produced by microorganisms. Through fermentation, microorganisms transform the organic constituents of food. For example, bacteria naturally present in cucumbers grow in the cucumbers

and partially digest the plant tissue into a flavorful pickle. Sausages are the product of microbial growth occurring within meat and spices. Different sausages can be made depending on the type of meat and spices used and the microorganisms that alter the chemistry of the meat. To bake

bread and rolls, the baker includes yeast in the dough to metabolize carbohydrates and form carbon dioxide, and the dough rises. Many dairy products are produced through the activity of microorganisms. For instance, cheese is manufactured by heating milk, adding enzymes to curdle the milk protein, and combining bacteria or molds with the milk curds. During the ripening process, microorganisms deposit the chemical compounds that give different cheeses their

distinctive tastes. For example, cheddar cheese takes its flavor from the acids produced by lactobacilli and streptococci growing within the ripening curd. Yogurt is a form of milk in which bacteria have produced acid from the milk sugar, and made the milk sour.

Microorganisms are nature's great recyclers of elements. Some bacteria, for example, release nitrogen from animal waste. Other microorganisms grow on the roots of pod-bearing

plants and bring nitrogen back into the cycle of life by using nitrogen to make organic compounds. These compounds are released into the soil where they are utilized as nutrients by plants, such as potatoes.

The range of industrial products of microorganisms is broad and includes such diverse products as perfumes and the antibiotic penicillin. Also, the bacterial enzyme protease removes organic debris from animal hides in the manufacture of leather. Certain bacteria produce enzymes that accelerate the transformation of organic compounds. For example, the enzyme pectinase decomposes the pectin fibers that bind cellulose fibers in plants. Once the pectin is dissolved, the cellulose can be spun to form linen. Other bacteria are employed to produce enzymes to form a starch used in the sizing of porous material during paper processing.

Many microorganisms are used as models and tools in research laboratories to study life processes. This is because the chemistry of microorganisms is similar to that of all other living organisms. In one technique, called genetic engineering, genes from other organisms are inserted into bacteria. This technique programs the bacteria with genetic instructions for the manufacture of a number of chemicals, such as insulin. Insulin is a hormone that maintains the metabolic machinery of the body and is essential to life. In juvenile onset diabetes mellitus, the hormone is in short supply. Insulin produced by genetically engineered bacteria can be taken by the sophisticated dispensing device.

Throughout history, microorganisms have posed formidable challenges to humans as infectious agents of disease. When transmitted from one person to another, certain microorganisms have been responsible for diseases such as plague, smallpox, typhoid fever, syphilis, and AIDS. Modem populations continue to be confronted with life-threatening, as well as irritating and inconvenient infections. One example of the latter is the fungal foot disease (athlete's foot).