Strain Improvement

Strain Improvement

Improvement of the production strain(s) offers the great opportunities for cost reduction without significant capital outlay in industries. Moreover, success in making and keeping a fermentation industry competitive depends greatly on continuous improvement of the production strain(s). Improvement usually resides in increased yields of the desired metabolite. The science and technology of manipulating and improving microbial strains, in order to enhance their metabolic capacities for biotechnological applications, are referred to as strain improvement.

Need for strain improvement

Microbes exist in the nature produce certain compounds of biological interest. However the industrial application of producing those compounds by natural strains is not an economical one so, wild strains are changed by the changing their gene pattern or by regulating their enzymes production. As a result, the specific product is produced in excess.

Knowledge of the function of enzymes, rate limiting steps in pathways, and environmental factors controlling synthesis further helps in designing screening strategies.

Attributes of Improved strains

1. Assimilate inexpensive and complex raw materials efficiently.

2. Alter product ratios and eliminate impurities or by products in downstream processing.

3. Reduce demand on utilities during fermentation (air, cooling water, or power).

4. Provide cellular morphology in a form suitable for product separation.

5. Create tolerance to high product concentration.

6. Shorten fermentation times.

7. Overproduce natural products or bioactive molecules not synthesized naturally for example insulin.

8. Excrete the product to facilitate product recovery.

Generally wild strains of microorganisms produce low quantities of commercially important metabolites. So, genetic improvements have to be made and new strains need to be developed for any substantial increase in the product formation in a cost effective manner.

Protoplast fusion is defined as fusion of two different protoplasts. A cell wall less nature of plant, bacteria, fungal is called protoplast. It is re moved by either mechanical or enzymatic means. Protoplast has nucleus other protoplasmic contents which are surrounded by cytoplasmic membrane.

HOTS

An organism is isolated from soil, which is a very low yielding one. How will you enhance the production activity?

The following techniques at practical genomic level help to improve the microbial strain. They are:

1. Selection of mutants

2. Recombination

3. Regulation

4. Genetic engineering

5. Protoplast fusion