Strain improvement is defined as the process of improving the production and yielding capacity of a microorganism through certain (deliberate) technological, microbiological, biotechnological, or biochemical process. Microorganisms of industrial importance must possess some certain qualities as aforementioned in this chapter – which will determine their usage for industrial productions. After their isolation from their natural habitat or environment, the microorganisms intended for industrial processes are usually tested and certified fit for the process. Generally, organisms for industrial productions are screened and isolated from the environment especially from the soil; and then these microbes are tested for the production of specific metabolites. Once deciphered, the isolated microorganism can be manipulated to produce its desired metabolite in a large amount for further industrial production. This is one of the main reasons of considering strain improvement in industrial microbiology. It is noteworthy to mention that the microorganisms isolated from the environment for industrial use may not fulfill all the requirements that are expected of an ideal industrial microbe. To make the isolated organism become more industrially important, the isolated organism must pass through certain deliberate technological manipulations aimed at improving its efficiency and productivity in industrial processes.

The main reason of carrying out strain improvement in industrial microbiology is to achieve a stable production with a high titer and ideal production profile. Microorganisms of industrial importance could be genetically manipulated to produce more of their metabolites under short time intervals while utilizing the minimal amount of substrates. Strain improvement is an important aspect of process development in most fermentation industries; and it is one of the major ways through which production costs in the industry can be reduced or made more effective and sustainable. It contributes to the maximization of profit in an industrial company pursuing industrial fermentation processes. This is partly because strain improvement helps to improve the product-yielding capacity of the industrial microbes – thereby cutting down on the cost of production. Slower-growing microbes and microbes that yield little amount of their metabolites are of no value in industrial productions because they lead to increased cost of production – which is against the objectives of industrial microbiology. However, through strain improvement, the yielding capacity and productivity of an underperforming microbe could be improved upon.

Since the primary and secondary metabolic pathways of these industrial microorganisms are mainly controlled by their genetic makeup – which determines the level and amount of metabolite that they produce under certain conditions; the alteration of their genome for the sole purpose of improved productivity will help in making such an organism an important asset in the industrial process. And this is what strain improvement does to wildtype industrial microorganisms, and make them to be more productive and efficient in industrial productions. Microorganisms of industrial importance could be manipulated to grow rapidly and use simple and cheaper substrates for growth during fermentation processes. Their genetic makeup could also be made to be more genetically stable; and industrial microbes could also be made to downregulate the production of a metabolite that is not of industrial importance. Through strain improvement, industrial microbes could be made to be resistant to certain substances in their environment that could affect their growth and overall metabolism. Some of the methods of achieving strain improvement of industrial microbes are through genetic recombinations, mutations or mutagenesis, and through recombinant DNA technology or genetic engineering techniques.


  • Strain improvement helps to improve the productivity of an organism.
  • It also improves the metabolic yield or output of microbes.
  • Strain improvement helps to maintain the strain purity of industrially important microbes.
  • It helps to produce or prepare a reliable inoculum for a given industrial process.
  • With strain improvement, the economic efficiency of industrial processes could be improved upon through the continuous development and improvement of selected industrial microbes.
  • Strain improvement alters the genetic makeup of an industrial microbe for economic reasons.
  • It is used to enhance the enzyme production capacity of an industrial microbe.
  • It is an important aspect in the isolation and purification of industrial microbes from their natural environment.


Bader F.G (1992). Evolution in fermentation facility design from antibiotics to   recombinant proteins in Harnessing Biotechnology for the 21st century (eds. Ladisch, M.R. and Bose, A.) American Chemical Society, Washington DC. Pp. 228–231.

Nduka Okafor (2007). Modern industrial microbiology and biotechnology. First edition. Science Publishers, New Hampshire, USA.

Parek S (2004). Strain Improvement. In: the motherland. The Desk Encyclopedia of Microbiology. M. Schaechter (ed.). Elsevier Amsterdam. Pp. 960-973.

Das H.K (2008). Textbook of Biotechnology. Third edition. Wiley-India ltd., New Delhi, India.

Latha C.D.S and Rao D.B (2007). Microbial Biotechnology. First edition. Discovery Publishing House (DPH), Darya Ganj, New Delhi, India.

Nester E.W, Anderson D.G, Roberts C.E and Nester M.T (2009). Microbiology: A Human Perspective. Sixth edition. McGraw-Hill Companies, Inc, New York, USA.

Steele D.B and Stowers M.D (1991). Techniques for the Selection of Industrially Important Microorganisms. Annual Review of Microbiology, 45:89-106.

Pelczar M.J Jr, Chan E.C.S, Krieg N.R (1993). Microbiology: Concepts and Applications. McGraw-Hill, USA.

Prescott L.M., Harley J.P and Klein D.A (2005). Microbiology. 6th ed. McGraw Hill Publishers, USA.

Steele D.B and Stowers M.D (1991). Techniques for the Selection of Industrially Important Microorganisms. Annual Review of Microbiology, 45:89-106.

Summers W.C (2000). History of microbiology. In Encyclopedia of microbiology, vol. 2, J. Lederberg, editor, 677–97. San Diego: Academic Press.

Talaro, Kathleen P (2005). Foundations in Microbiology. 5th edition. McGraw-Hill Companies Inc., New York, USA.

Thakur I.S (2010). Industrial Biotechnology: Problems and Remedies. First edition. I.K. International Pvt. Ltd. New Delhi, India.






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