Tag: biotechnology

S. cerevisiae is known for its role in food production. It is the critical component in the fermentation process that converts sugar into ethyl alcohol (ethanol), an ingredient shared in beer, wine and distilled beverages. It is also used in the baking process as a leavening agent; yeast releasing gas into their environment results in the spongy-like texture of breads and cakes. 

In a bread dough, where the oxygen supply is limited, the yeast can only partially breakdown the sugar. Alcohol and carbon dioxide are produced in this process known as alcoholic fermentation. The carbon dioxide produced in these reactions causes the dough to rise, and the alcohol produced mostly evaporates from the dough during the baking process. During fermentation, each yeast cell forms a centre around which carbon dioxide bubbles form. Thousands of tiny bubbles, each surrounded by a thin film of gluten form cells inside the dough piece. The increase in dough size occurs as these cells fill with gas.

Yogurt is a food produced by bacterial fermentation of milk. The bacteria used to make yogurt are known as yogurt cultures. Fermentation of lactose by these bacteria produces lactic acid, which acts on milk protein to give yogurt its texture and its characteristic tang. Some representative strains of yogurt cultures are Streptococcus lactis, S. cremoris, S. thermophilus, Lactobacillus bulgaricus, L. acidophilus, and L. plantarum.

Vitamin B$ _{12}$ cannot be made by plants or animals as only bacteria have the enzymes required for its synthesis. Members of the genus Propionibacterium are widely used in the production of vitamin B$ _{12}$.

Baker's yeast is the common name for the strains of yeast commonly used as a leavening agent in baking bread and bakery products, where it converts the fermentable sugars present in the dough into carbon dioxide and ethanol. Baker's yeast is of the species Saccharomyces cerevisiae, which is the same species (but a different strain) commonly used in alcoholic fermentation, which is called as brewer's yeast.

Microorganisms isolated based on their ability to degrade hydrocarbons often belong to the genus Pseudosmonas. These bacteria have several catabolic pathways and are easily handled and grown in the laboratory. Pseudomonas putida, a Gram-negative proteobacterium, possesses the outstanding ability to tolerate high concentrations of different hydrocarbons.

Useful antibiotics are often discovered using a screening process. To conduct such a screen, isolates of many different microorganisms are cultered and then tested for production of products that inhibit the growth of test organisms.They are tested for their selective toxicities and therapeutic activities, and the best candidates are examined and modified. Once the process is complete, the antibiotic must be extracted and purified to a crystalline product. The copies of genes coding for enzymes involved in the antibiotic production can be inserted into a cell, via vectors such as plasmids.

Scientic theories about the origin-of-life theories have historically been characterized by the chicken-and-egg problem of which essential aspect of life was the rst to appear, replication or self-sustenance. RNA, the other nucleic acid, contained building blocks very similar to DNA, so biologists recognized early that RNA could store information in its linear sequences. With the discovery in the 1980s that RNA molecules were capable of biological catalysis, a function till now ascribed to proteins alone, RNA took on the role of the single entity that could act as both chicken and egg. Within a few years of the discovery of these catalytic RNAs (ribozymes) scientists had formulated an RNA hypothesis that posited an early phase in the evolution of life where all key functions were performed by RNA molecules. 

Beverages of low alcoholic content (less than about 9% alcohol) are fermented from grains and are usually considered to be beers. Wines, on the other hand, are fermented to a higher percentage of alcohol (10 - 18% alcohol) and are usually fermented from fruit juice. Higher levels of alcohol kill or inhibit bacteria stopping spoilage as well as fermentation. Vodka, whiskey, and other alcoholic beverages with alcohol contents well above 20% are produced by distilling alcohol from a yeast-fermented beverage. Many liquors are produced by using distilled alcohol (as high as 95% alcohol) to extract various flavoring materials after which the resulting extract is diluted with water and often sugar to make a flavored alcoholic beverages. Unless the alcoholic content of the resulting beverage is well above 15%, the material will not be stable and may start to ferment or even decay in storage. Hence, most liquors are atleast 20% alcohol.

Biotechnology has a long history of use in food production and processing. For ten thousand years fermentation, a form of biotechnology, has been used to produce wine, beer and bread. Selective breeding of essential foods such as rice, corn and wheat have created thousands of local varieties with improved yield compared to their wild ancestors.