FERMENTATION

BY: ARCHANA PRIYADARSHINI JENA (MSIWM006)

SYNOPSIS:

  1. INTRODUCTION
  2. BACKGROUND OF FERMENTATION PROCESS
  3. FERMENTATION
  4. PRODUCT FORMATION
  5. TYPES OF FERMENTATION
  6. LARGE SCALE FERMENTATION
  7. DESIGN AND PARTS OF FERMENTORS
  8. INDUSTRIAL APPLICATIONS OF FERMENTATION PROCESS
  9. CONCLUSION

INTRODUCTION:

The science of fermentation is known as zymology. Microorganisms play an important role in the fermentation technology. Through their actions the fermentation process transforms and preserves food. Thousands of years ago, people have started fermenting food. Now we have other techniques to preserve food still the fermentation process persists. People are interested in fermented food due to its interesting flavours, their vitamins and enzymes, or organic acids and “good bacteria”.

BACKGROUND OF FERMENTATION TECHNOLOGY:

Fermentation comes under the umbrella of industrial microbiology (it’ the interdisciplinary study that uses microbes, to produce commercial products or carry out important chemical transformations usually grown on large scale). So fermentation can be carried out both in small scale and large scale production.

Now the microbial biotechnology joined with the industrial microbiology which leads to many fold increase of products and also to produce New products, by means of genetic manipulations of these microorganisms which are originally not produced by these microorganisms.

FERMENTATION:

Fermentation refers to any large scale process in which the commercial products like vitamins, enzymes, vaccines, organic acids are produced from the raw materials by using different microorganisms either aerobically or anaerobically.

In microorganisms, fermentation is the aerobic degradation of organic nutrients to produce adenosine triphosphate (ATP) for their growth.

PRODUCT FORMATION:

The product that is produced during fermentation(or microbial growth) was of two groups.

Primary metabolites : It’s the product which is formed during the active growth stage (log phase) of the microorganism.    

Ex. Alcohol produced by yeast. By the action of primary metabolic pathway of yeast (EMP         pathway), the alcohol is produced and will be accumulated during the active growth stage of yeast.

Secondary metabolites : These are the products which are formed either at the end of active growth stage or at the beginning of the stationary phase are referred to as secondary metabolites.

Example: Antibiotics are usually produced in the stationary phase. These are formed by the secondary       metabolic pathways That is not essential for the growth of microorganisms. Few organisms show this characteristic.

TYPES OF FERMENTATION :

There are various types of fermentation process based on its characteristics.

Based on the state, the fermentation process can be classified into two.

Submerged (liquid) fermentation : Fermentation is carried out in liquid forms.

Ex. From sugarcane industrial waste alcohol can be produced- Molasses by yeast.

Solid fermentation : With about 30-50% moisture level the Fermentation is carried out in solid condition.

Example: Gibberellic acid produced from grains by fungus Fusarium moniliformi

Based on the microbial growth (culturing method):

Batch fermentation : It is a closed system of microbial fermentation in which the volume is already fixed.

Fed batch fermentation : As the fermentation process is continuing the substrate for fermentation (raw material) is added in increments.

Continuous fermentation : It is an opened system of microbial fermentation in which the input (nutrients solutions or media) is added continuously with the withdrawal of equal portion of converted or fermented solution.

LARGE -SCALE FERMENTATIONS:

Fermentation process is carried out in a closed vessel which is called as Fermentor. The volume of the Fermentor may varies from 5-10 lit to 500,000 lit. Similarly the Fermentor model will vary for both aerobic and anaerobic process.

DESIGN AND PARTS OF FERMENTOR :

There are various types of Fermentor. But the basic structure of Fermentor is as follows:

 The components are:

  • Inlet : to add the the substrates for microorganisms etc
  • Outlet : to collect the products and check the samples
  • Stirrer : to mix the contents inside the Fermentor
  • Air sparger : by releasing small bubbles into the Fermentor to provide oxygen to the microorganisms
  • pH meter : to check the pH and maintaining by adding acid or alkali
  • Thermometer : to check the temperature
  • Outer jacket : for cooling process ( because during the Fermentation, lot of heat will be generated)
  • Sterilization unit : stem is supplied to sterilize the medium and container
  • Scale up : it refers to sequence wise step in any Fermentation to yield Maximum product

Fermentor Model

Scale up of fermentation

INDUSTRIAL APPLICATION OF FERMENTATION PROCESS :

Presently, “ Fermentation technology” is replaced by the word “Bioprocess technology” . The commercial products formed by the fermentation technology is very useful for the industrial purposes.

The following are the commercial products obtained through the fermentation process by different microorganisms.

 Antibiotics

Most of the antibiotics can be produced by microbial fermentations. Sometimes, the antibiotic needs to be modified through some chemical processes, referred as semi- synthetic antibiotics. Here are some antibiotics and the organisms involved in its production.

AntibioticsOrganism
CephalosporinCephalosporium
PenicillinPenicillium chrysogenum
StreptomycinSreptomyces griseus

Vitamins

Vitamin B12 and Riboflavin are vitamins which is commercially produced by pseudomonas denitrificans and Ashbya gossipii respectively.

Amino acids

L-glutamate, L- aspartate, glycine, cysteine, tryptophan etc are some common amino acids commercially produced by microbes.

Presently, these amino Acids can be produced by genetically modified bacteria.

Bio conversion

For conversion of one compound to another product the microorganisms act as bio-catalyst in bio conversion process.

Ex. Most of the steroids are produced by this process

Enzymes

Enzymes can also be produced by fermentation process which is mostly used in food industry and molecular biology.

The following table shows the enzymes and the involved organisms

EnzymeOrganism
LipaseAspergillus, Candida
ProteaseBacillus licheniformis
DNA polymeraseThermus aquaticus
AmylaseBacillus licheniformis, Aspergillus

Chemicals

Acetic acid, citric acid, acetone, butanol etc are produced by microorganisms.

ChemicalsOrganism
Acetic acidAcetobacter
Lactic acidLactobacillus
Citric acidAspergillus niger

 Single cell protein

By using fermentation technology protein is also  produced which can be used as food referred to as Single cell proteins (SCP)

Example: The yeast, chlorella, spirulina etc .

Alcohols and alcoholic beverages

The yeast play a major role in the alcohol industry. As we know it is a facultative aerobe it can be grown aerobically and anaerobically. When, yeast grows aerobically its biomass increased with low alcohol, used for the production of baker yeast while if it grows anaerobically, the alcohol production will be Maximum.

Example: Whiskey, rum, otka etc  are the commercial preparations of alcohol.

Food

The microorganisms itself can be used as food. Following are some of the foods obtained from microbes.

  • Mushroom : Agaricus bisflorus(button mushroom)
  • Bread : by yeast
  • Butter, yogurt, dairy products : Lactobacillus, Leuconostoc

Vaccines

Vaccines are the immunized antigens which has part of cell or whole cell or cell product. Presently viral DNA also act as vaccine which is referred as DNA vaccines are commercially produced.

CONCLUSION:

Downstream processing is the product recovery process that is to collect the final product after the fermentation process. Beside this the waste management need to be done after every fermentation.

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