Currently, cell culture of higher plants is an alternative method for obtaining biomass of rare medicinal plants. Compared with the use of conventional plants, the application of plant cell technology has several advantages, in particular:
- the possibility of obtaining the necessary quantities of a quality product with reproducible characteristics under sterile controlled conditions;
- climate independence and political independence;
- the possibility of making changes in the structure and biochemistry of plant tissues to obtain new substances that are not characteristic of a wild plant;
- ease of production and cleaning of the product.
Biotechnology and plant cell culture
Biotechnology is a discipline that studies the possibilities of using living organisms, their systems or their metabolic products to solve technological problems, as well as the possibility of creating living organisms with the necessary properties Biotechnology is based on genetics, molecular biology, biochemistry, embryology and cell biology, as well as applied disciplines - chemical and information technology and robotics.
is the process by which individual cells (or a single cell) are artificially grown under controlled conditions. In practice, the term "cell culture" refers mainly to the cultivation of cells belonging to the same tissue, derived from multicellular eukaryotes, animals or plants. The historical development of technology and methods of growing cell cultures is inextricably linked with the cultivation of tissue cultures and whole organs.
Due to this property, each cell of the plant is able to ensure the development of the whole plant. It should be noted that, unlike an animal, a plant cell imposes less stringent requirements on cultivation conditions. Changing conditions (adding certain hormones to the nutrient medium) can cause the differentiation of non-deterministic cells. The culture of plant tissue allows to obtain numerous populations in a relatively short time and in a limited space.
The main type of cultivated plant cell is callus. Callus tissue is one of the types of cell differentiation, it occurs by the unorganized proliferation of undifferentiated cells of plant organs. In plants, callus tissue in nature occurs in exceptional circumstances (for example, in case of injuries) and functions for a short time. This tissue protects the site of injury, can accumulate nutrients for anatomical regeneration or regeneration of a lost organ. Normal cells in culture can exist in two forms: in the form of a suspension in a liquid nutrient medium and on the surface of a solid nutrient medium in the form of callus.
Suspension cultures are individual cells or groups of cells grown in suspension in a liquid medium. They are a relatively homogeneous cell population that is easily exposed to chemicals. For the cultivation of suspensions on an industrial scale, an apparatus developed for the microbiological industry is used, but recent studies have shown that, due to their specific characteristics, plant cells require special vessels for cultivation. Plant cells are dozens, hundreds of times larger than bacteria and fungi, in addition, their sizes change during ontogenesis. If at the beginning of the growth of the culture they are small and dense, then in the next growth phase they greatly increase in size. The larger the cell becomes, the greater the risk of its mechanical damage during mixing. At the same time, plant cells, large and heavy, require efficient mixing. Their sedimentation leads to the appearance of "dead" zones in the vessels, in which there is a rapid accumulation and aging of cells. The resistance of the strain to mechanical stress is an important requirement for culture and a difficult task for researchers. Soft mixing and aeration provides by a stream of compressed sterile air supplied to the fermenter with an upward current of air. Unfortunately, this method also has its drawback, because there is an excess of air in the culture medium, leading to oxygen starvation. The growth and secondary metabolism of cells depend on the concentration of oxygen in the medium. Periodic, or accumulative, cultivation is the easiest way to grow cells, which is still traditional. Suspension cultures are used for industrial production of secondary metabolites. Substances produced by plant cells are used in medicine, the perfume industry, the plant industry and other industries. These include: alkaloids, terpenoids, glycosides, polyphenols, polysaccharides, essential oils, pigments, anticarcinogens (phtothecin, harringtonin), peptides (phytovirus inhibitors). Currently in different countries about a hundred species of plants used in the biosynthetic industry to produce economically important substances, among them - ginseng, Rauwolfia serpentina, digitalis lanata and purple, Dioscorea deltoid, lithospermum, belladonna, nightshade lobed, Datura stramonium, lily of the valley, castor , agave and others.
Obtaining secondary metabolites
Cell division, leading to an increase in cellular biomass, and the synthesis of secondary metabolites are separated in time. The accumulation of secondary metabolites increases in the phase of slow growth of the cell population and reaches a maximum in the stationary phase. Some alkaloids are actively synthesized in the phase of maximum mitotic activity (exponential growth), which is an exception. The knowledge of such laws allows to regulate the processes of obtaining valuable substances. Mechanisms and conditions that block active cell growth and cell proliferation simultaneously activate secondary metabolism enzymes. Nonspecific stress conditions affecting cells at the end of the exponential phase can stimulate the transition to the synthesis of secondary metabolites and increase their yield. It should be borne in mind that the question of the interaction of the primary and secondary metabolism, which we considered in a simplified form, is much more complicated.
Used in our company for the production of plant biomass on an industrial scale. In them mechanically there is a constant mixing of undifferentiated plant cells so that they constantly divide and do not form tissues and organs. Thus, the cells are constantly increasing their biomass and, accordingly, are constantly synthesizing nutrients, which are used in the production of our products.