Fermentation : Defination, Principle and Batch Fermentation Method

 The process of fermentation involves biochemical activity of organisms during their growth, development, reproduction, senescence, and death. Fermentation technology employs organisms to produce food, pharmaceuticals, and alcoholic beverages in industries on a large scale.

Principle of Fermentation

The principle involved in industrial fermentation technology is that organisms are grown under optimum conditions and are provided with raw materials and other necessary requirements like carbon, nitrogen, salts, trace elements, and vitamins. The end products formed due to their metabolism during their life span are released into the media. These end products are extracted by human beings as they are commercially valuable.

Some major end products of fermentation produced on a large scale industrial basis are wine, beer, cider, vinegar, ethanol, cheese, hormones, antibiotics, complete proteins, enzymes, and other beneficial products.

Batch Fermentation

In batch fermentation process, the microorganisms are inoculated in a fixed volume of batch culture medium. The organisms during their growth consume the nutrients, and the growth products (i.e., biomass and metabolites) start accumulating. Since the nutrient environment within the Fermenter is continuously changed, the rate of cell metabolism also changes, and ultimately, cell multiplication stops due to limitation of nutrients and accumulation of toxic excreted waste products.

Growth Characteristics in a Batch Culture of a Microorganism. 1) Lag Phase, 2) Transient Acceleration, 3) Exponential Phase, 4) Deceleration Phase, 5) Stationary Phase, 6) Death Phase

There is the complex nature of batch growth of microorganisms. In the initial lag phase, no apparent growth is observed; however, biochemical analyses show metabolic turnover signifying that the cells are acclimatising to the environmental conditions and will start growing. Then comes the transient acceleration phase when the inoculum begins to grow. This phase is quickly followed by the exponential phase where the organisms are growing at fastest rate as the nutrients are in excess, environmental conditions are optimum and growth inhibitors are absent.

In the batch fermentation process, the exponential growth occurs for a limited period. With the change in nutrient conditions, the growth rate decreases and begins deceleration phase followed by the stationary phase at which the growth sto completely because of nutrient exhaustion. The death phase when the grow rate has come to an end is the final phase of the cycle. Mostly t biotechnological batch processes are stopped before this stage because decreasing metabolism and cell lysis.

Advantages of Batch Fermentation

  1. It Requires less space.
  2. It Can be easily handled, and
  3. There is Less chances of contamination.

Disadvantages of Batch Fermentation

  1. It is time consuming method.
  2. It requires more time for cleaning, sterilisation, and cooling.
  3. Product yield is low.