BIOTECHNOLOGY - Inshyna N.M. - 2009

INTRODUCTION

Objects of Biotechnology

The objects of biotechnology are living organisms, as well as their cellular components. The Earth's biosphere is extremely diverse. To date, about 300,000 different plant species and over 1 million animal species are known (Table 1).

Class="center">Table 1

Number of biological species inhabiting the modern Earth

The main objects of biotechnology include: subcellular structures (viruses, Plasmids, Cell/39.html">Mitochondrial and Chloroplast DNA, nuclear DNA), microorganisms (bacteria and cyanobacteria, fungi, algae, Protozoa), insect, plant, and animal cell lines, and Multicellular Organisms (plants, animals).

Bacteria and Cyanobacteria

Among bacteria, the bacterium Escherichia coli is most frequently used in biotechnological research. E. coli is a Gram-negative bacterium of the Enterobacteriaceae family and a facultative anaerobe. It is a non-pathogenic, motile bacterium less than 1 — 2 µm in length. E. coli is a resident of the normal intestinal microflora of mammals and also inhabits soil and Water. It reproduces by binary fission every 22 minutes.

In 1922, the E. coli K-12 strain was isolated and is now used in experimental research. This strain has lost its viability in the human intestine and cannot reproduce or persist for long periods outside the laboratory. The E. coli K-12 strain is non-toxic and non-pathogenic to humans.

E. coli serves as a producer of many useful substances. It is estimated that the Cytoplasm of E. coli contains 200 million carbohydrate molecules, 30 million amino acid molecules, 1 million protein molecules (of 5,000 different types), and 25 million lipid molecules. Each bacterial cell contains 10,000 Ribosomes.

Bacteria are used in the industrial production of the following compounds:

- vinegar (Acetobacter and Gluconobacter suboxidans);

- lactic acid products (Lactobacillus, Leuconostoc);

- PROTEIN AND AMINO acids (Methylomonas, Corynebacterium);

- Vitamins (Clostridium);

- Solvents and organic acids (Clostridium).

Bacteria are also used for biogas production, ore leaching and mining waste disposal, biotransformation of industrial and municipal waste, and fixation of

atmospheric nitrogen. In Introduction/32.html">Genetic Engineering, bacteria are used to construct Genomic Libraries.

Fungi

Among eukaryotic microorganisms, the Yeast Saccharomyces cerevisiae is most commonly used in biotechnology. These are non-pathogenic microorganisms approximately 5 µm in length. S. cerevisiae reproduce by budding.

In 1996, The Genome of S. cerevisiae was fully sequenced. It was established that most S. cerevisiae genes regulating Cell Division are similar to human genes.

Out of 500 known yeast species, S. cerevisiae

was the first to be cultivated for alcohol production. Over 1 million tons of these Yeasts are used worldwide annually.

In the biotechnology industry, fungi are used to produce the following products:

- Antibiotics (Penicillum, Streptomyces);

- plant growth Hormones - Auxins and Gibberellins (Fusarium);

- carotenoids (Rhaffia rhodozima);

- protein (Saccharomyces lypolitica, Candida);

- Enzymes (Penicillum);

- soy sauce (Aspergillus oryzae);

- cheeses such as Roquefort and Camembert.

Food products based on soybeans or wheat fermented with the mold fungi Rhizopus oligosporus contain 5 to 7 times more vitamins (riboflavin, nicotinic acid) and several times more protein.

Protozoa

Protozoa are unconventional biotechnology objects, most commonly used as a component of activated sludge in wastewater Treatment. Flagellated protozoa are utilized for Lipid Biosynthesis, while euglenid flagellates serve as producers of Polysaccharides.

Representatives of the genera Astasia and Euglena synthesize the polysaccharide paramylon (50% of cell dry weight), which acts as an immune system stimulant for mammals and exhibits antitumor activity. Euglenids are producers of glucans—structural Heteropolysaccharides (containing glucose, mannose, xylose, arabinose, ribose, galactose, rhamnose, fructose, and glucosamine) used in medicine, the food industry, and the textile industry.

Algae

The primary application of algae is protein production. At least 100 species of algae are used for food (kelp, Alaria, Porphyra, Rhodymenia, Chondrus, Undaria). Protein hydrolysates from unicellular algae of the genera Chlorella and Scenedesmus are used in medicine and the food industry.

Algae are producers of polyhydric alcohols. For example, the unicellular alga Dunaliella bardawil synthesizes significant amounts of glycerol (85% of cell dry weight). Brown algae synthesize the hexahydric alcohol mannitol, which is used in the food and paper industries, Pharmaceuticals, and the manufacturing of explosives.

Algae are the sole source of Agar, agaroids, carrageenan, and alginates. Red algae (Laurencia, Gracilaria, Gelidium) are used to produce the polysaccharide agar. The agar content ranges from 30–40% of the algal dry weight.

Brown algae are a source of alginates—salts of alginic acid used to manufacture the following Materials:

- high-quality lubricants for machine parts;

- medical preparations;

- synthetic fibers and plastics;

- durable coatings and paints;

- silk;

- adhesives and building materials;

- food products (fruit juices, ice cream).

In agriculture, algae are used as fertilizers; their biomass enriches the soil with Phosphorus, Potassium, Iodine, and Trace Elements, while also supporting bacterial nitrogen-fixing microflora.

Eukaryotic Cell Cultures

Eukaryotic cell cultures are used to study the biochemical properties of various Tissues, as well as to produce valuable substances. The subjects of biotechnology include plant, animal, and human cell lines.

Cell cultures capable of unlimited growth in vitro are referred to as cell lines. Cell lines are utilized for virus propagation, as well as for The production of recombinant Proteins and Vaccines.