Applied microbiology is the application of basic knowledge of microbiology into the betterment of human society. Any process which is done using microorganism from the simple curdling process to the complex bioremediation process, all come under the umbrella of applied microbiology.
In this blog, we will consider some of the latest application of microbiology some of which are the production of beer, production of vitamin B12, bioleaching, biosurfactants, MEOR, biogenic nanoparticles, yeast production, mushroom production, biogas and bioethanol production, microbial polysaccharides, microbial pigments, microbial production of PHB.
Before we dig into the applications some of the fundamental topics should be cleared first such as primary and secondary metabolites, ideal characteristics of microorganism used in industries, basics of upstream and downstream processes, fermenter design, laboratory design in the industry.
The life cycle of microorganism follow major four stages of life cycle, namely lag phase, log phase or exponential phase, stationary phase and death or decline phase.
- Primary metabolites are those metabolites essential for the growth and development of microorganisms.
- These are produced during the active growth period that is the log phase when the microorganisms are exponentially multiplying.
- These are usually extracellularly produced and exoenzymes are essential in breakdown and intake of food material.
- For example ethanol, lactic acid, amino acids such as Glutamic acid etc.
- These metabolites may not be directly essential for growth and division of microbial cells but are important for the survival of cells.
- These are produced during the stationary phases of the life cycle and are important for maintenance of microorganisms.
- These are extracellularly produced.
- For example antibiotics, microbial polysaccharides, polyhydroxyalkanoates etc.
Ideal characteristics for industrially important microorganisms
- Growth requirement: the microbe being used must not require a very expensive growth media, rather should be able to grow and extract the available nutrients from complex medium in other industrial wastes such as molasses(sugar industry waste), cotton waste, sugarcane waste, agricultural waste(corn cob, straw, husk etc.). The microorganism should also be able to grow and sustain in a wide range of growth conditions such as temperature, pH, redox potential, aeration etc.
- Growth type: the microbe used should show vigorous and luxuriant growth i.e. it should multiply rapidly over a short period of time. The shorter the generation time the better would be the profit for the industry.
- Product development: the organism must show profluent growth as well as should produce the desired product in high concentrations.
- By-products: production of the desired products requires energy and the raw material and when the organism uses this expense in the generation of an excess of by-products it turns out to be a huge loss for the respective industry. It is also essential that the organism being used must not produce any toxic compounds which increase the cost of down streaming process.
- Stability: stability is an important aspect in microbiology as the organisms used mostly are genetically engineered to produce a product or the organism is modified using other techniques to be used in an industry and when such an organism mutates it leads to generation of toxins, reduced or no production of desired products, or excess production of byproducts. Usually, extremophilic microorganisms are used as they are stable under extream conditions and have lesser chances of mutation in production conditions.
- Harvesting method: in the industrial production of any microbially produced product the cost of down streaming weighs one-third of the total production cost as the separation and purification of the product has various complex steps require expensive machinery. So it is important to have an easy recovery and purification method with the best level of purification possible.