Development of a bioprocess for the production of actinomycin-D
I then tested the effect of other amino acids and observed that lysine was the idiophase-trophophase relationship of secondary metabolism. TROPHOPHASE-IDIOPHASE RELATIONSHIPS IN THE PRODUCTION OF SECONDARY PRODUCTS: From studies on Penicillium urticae the. and metabolism influence both the temporal relationship between trophophase and idiophase and the final titre of antibiotic achieved by producing cultures.
The products are called as secondary metabolites idioliteswhich are produced at the end of the process. This phase occurs at the period of the limited nutrient or when there is the accumulation of the waste products. Although the compounds like antibiotics, alkaloids, steroids, gibberellins, toxins, etc. Hence secondary metabolites are considered as the end products of the primary metabolites.
Importance of the secondary metabolites Secondary metabolites are produced by very specific microorganisms only, mainly antibiotics and other products are used.
Generally microorganisms synthesize numerous group of secondary metabolites compounds instead of one, for example, a strain of Streptomyces produces 35 anthracyclines at a time, instead of one.
These are not required for the growth, reproduction, and development of the cell. As stated above, that secondary metabolites do not directly benefit the cell growth and development, but they perform some unknown function which supports the cell survival.
Key Differences Between Primary and Secondary Metabolites Following are the noteworthy points which distinguish the primary metabolites to that of the secondary metabolites: The primary metabolites are considered as the products that are produced during the growth phase of organisms and are primarily involved in the growth and development of an organism. On the other hand, secondary metabolites are said to be as the end products of the primary metabolites, involved in the stationary phase during the growth of a microorganism and play a role in ecological functions.
Primary metabolism pathway occurs at the growth phase and is also known as trophophase while the secondary metabolism pathway occurs at the stationary phase and is also known as idiophase.
Primary metabolites are produced in large quantities, and their extraction is easy, in fact, the products are same in every species, whereas secondary metabolites are produced in small quantities, and their extraction is difficult, even their products are different for different species. The products manufactured during the primary metabolism pathway are useful in industries for various purpose and also plays very important role in the cell growth, reproduction and development.
Whereas secondary metabolites such as antibiotics, gibberellins are also important and they also indirectly support the cell, in their survival for a long time. Several metabolic products, collectively referred to as primary metabolites, are produced in trophophase i. The primary metabolites are divided into two groups: These are the compounds produced in adequate quantizes to sustain cell growth e.
The native microorganisms usually do not overproduce essential primary metabolites, since it is a wasteful exercise. However, for industrial overproduction, the regulatory mechanisms are suitably manipulated. Primary metabolic end products: These are the normal and traditional end products of fermentation process of primary metabolism.
Primary Metabolites, Secondary Metabolites and Bioconversions
The end products may or may not have any significant function to perform in the microorganisms, although they have many other industrial applications e. Carbon dioxide is a metabolic end product of Saccharomyces cerevisiae. This CO2 is essential for leavening of dough in baking industry.
However, the metabolism does not stop. It continues as long as the cell lives, but the formation of products differs. Overproduction of primary metabolites: Excessive production of primary metabolites is very important for their large scale use for a variety of purposes. Overproduction of several metabolites has been successfully accomplished by eliminating the feedback inhibition as briefly described below: By using auxotrophic mutants with a block in one of the steps in the biosynthetic pathway concerned with the formation of primary metabolite this should be an intermediate and not the final end product.
Difference Between Primary Metabolites and Secondary Metabolites
In this manner, the end product E formation is blocked, hence no feedback inhibition. But overproduction of the required metabolite C occurs as illustrated below. In the above example, an un-branched pathway is shown. This type of manipulation for overproduction of metabolites can be done for branched metabolic pathways also.
Mutant microorganisms with antimetabolite resistance which exhibit a defective metabolic regulation can also overproduce primary metabolites. As the exponential growth of the microorganisms ceases i. Idiophase is characterized by secondary metabolism wherein the formation of certain metabolites, referred to as secondary metabolites idiolites occurs.How Do You Love? A New Personality Test
These metabolites, although not required by the microorganisms, are produced in abundance. The theories in currency are discussed below; even then none of these can be said to be water tight. In this theory which refers to antibiotics specifically, secondary metabolites antibiotics enable the producing organism to withstand competition for food from other soil organisms.
METABOLIC PATHWAYS FOR BIOSYNTHESIS OF INDUSTRIAL MICROBIOLOGY PRODUCTS CONTD..
In support of this hypothesis is the fact that antibiotic production can be demonstrated in sterile and non-sterile soil, which may or may not have been supplemented with organic materials.
As further support for this theory, it is claimed that the wide distribution of Beta-lactamases among microorganisms is to help these organisms detoxify the Beta-lactam antibiotics. The obvious limitation of this theory is that it is restricted to antibiotics and that many antibiotics exist outside Beta-lactams. Secondary metabolism usually occurs with the exhaustion of a vital nutrient such as glucose.
It is therefore claimed that the selective advantage of secondary metabolism is that it serves to maintain mechanisms essential to cell multiplication in operative order when that cell multiplication is no longer possible. Thus by forming secondary enzymes, the enzymes of primary metabolism which produce precursors for secondary metabolism therefore, the enzymes of primary metabolism would be destroyed.
In this hypothesis therefore, the secondary metabolite itself is not important; what is important is the pathway of producing it. Similar to the maintenance theory, this hypothesis states that control mechanisms in some organisms are too weak to prevent the over synthesis of some primary metabolites. These primary metabolites are converted into secondary metabolites that are excreted from the cell.
If they are not so converted they would lead to the death of the organism. This hypothesis states that molecules accumulated in the cell are detoxified to yield antibiotics.