Question

Source of vitamin and mimerals in fermentation media

Answer 1

Fermentation media consists of major and minor components.

Major components include Carbon and Nitrogen source.

Minor components include inorganic salts, vitamins, growth factors, anti-foaming agents, buffers, dissolved oxygen, other dissolved gases, growth inhibitors and enzymes.

Nutrients required for fermentation media also depend upon the type of fermentation organisms as well as the type of fermentation process to be used. Poor choice of fermentation media might result in poor yield of output. Types of nutrients present in the fermentation media always determine the yield of the product.

There are two uses of fermentation media

Growth media

Fermentation media

Growth medium contains low amounts of nutrients.It is useful in creating raw material for further fermentation processes.

Fermentation media contains high amounts of nutrients. It is used in creating final products using fermentation.

For example, growth of yeast requires 1% carbon. But during fermentation of alcohol, yeast requires 12 to 13 % carbon in the medium.

What is the role of Fermentation Media?

During the fermentation process, media contains high amounts of nutrients, micro-organism and optimum conditions. When these micro-organisms are incubated at the desired optimum conditions, they enjoy luxurious metabolism. Here, the fermentation organisms become hyperactive due to presence of high quantities of nutrients, thus it results in consumption of excess nutrients and partial degradation of fermentation media. The waste effluents excreted by the microbes could be the desired output product of the fermentation process.

The amount of substrate given to microbes should not reach inhibitory concentration levels because excess substrate inhibits vital enzymes and may results in death of cells. Also, water present in cytoplasm is important for metabolism process. If excess sugar or salt is available in the fermentation media, it would tie up cytoplasm water and may result in lack of water for metabolism and cause death of microbes, thus affecting fermentation output.

Excess substrate may increase osmotic pressure and effect enzyme activities in a cell. Microbes excrete this excess substrate in the form of partially digested fermentation media. It is converted to an insoluble inert compound in the form of reserve food material and this reserve food material is harmless to cells.

There are two types of fermentation media used in industries.

Synthetic media

Crude media

Let us discuss these types of media.

Synthetic media

Synthetic media is useful in the field of research as each and every component is chemically known and the exact composition of nutrients is predetermined. So, in case of synthetic media, variation in levels and concentration of nutrients can be controlled. Here, by experimentation with synthetic media, the effect of nutrients on growth and yield of product can be analysed. We can redesign the synthetic media as per our needs. It is very useful in controlling the  growth and yield of product in a lab environment. We can also use it to determine the metabolic pathway used in the synthesis of products.

Crude Media

Crude media is generally used on an industrial scale for fermentation process. Crude media contains a rough composition of media required for fermentation. It gives high yield of product and contains undefined sources of ingredients. Crude media contains high level of nutrients, vitamins, proteins, growth factors, anti-foaming agents and precursors. It is important to ensure that crude media should not contain toxic substances that could effect the growth of bacteria and yield of product.

Ingredients of Crude Media

1) Inorganic nutrients

Crude media contains inorganic salts containing cations and anion along with a carbon source. Sometimes, fermentation micro-organisms have a specific requirement of ions like magnesium ions, phosphates or sulphates. These requirements are fulfilled by addition of these ions to balance the crude media.

2) Carbon source

Simple to complex carbohydrates can be added to media as a source of carbon.

Simple carbohydrates – simple sugars are semi purified polysaccharides and sugar alcohol are added. Sources of simple carbohydrates are Black strap molasses, Corn molasses, Beet molasses, sulphite waste liquor, Hydrol (corn sugar molasses), Cannery waste.

Complex carbohydrates – Source of complex carbohydrates are Starch, Corn, Rice, Rye, Milo, wheat potatoes etc.