Basic concepts of Microbial fermentation

1. Basic Concepts of Fermentation
Dr. Dhanya KC
Assistant Professor
Department of Microbiology
St. Mary’s College, Thrissur-
680020
Kerala

2. The word fermentation - Latin word ‘fervere’ - to boil
Boiling appearance of fruit juice or malted grain by the
action of yeast - generation of CO2 bubbles
Biochemistry
- Energy generation by anaerobic catabolism
Industrial microbiology
- Process for production by culture of microbe
- Both aerobic and anaerobic processes

3. 5 major groups of commercial fermentations
1. Microbial cells (biomass) as the product
2. Produce microbial enzymes
3. Produce microbial metabolites
4. Produce recombinant products
5. Transformation process

4. 1. Microbial biomass
Production of yeast – inoculum for other fermentations
Production of microbial cells - single-cell protein- food
2. Microbial enzymes
Highly utilized
Microbial system possess high productivity
Recombinant DNA technology - microbial synthesis of
enzymes of animal origin

5. 3. Microbial Metabolites
Intermediates and products of metabolism
1o metabolites - Synthesis
during exponential phase, Part of
normal growth
• Intermediates and products of
anabolism - building blocks
e.g. amino acids, nucleotides, vitamins
• Intermediates from catabolism -
not building blocks, but related to
energy production
e.g. citric acid, acetic acid, ethanol
2o metabolites
Synthesis during Stationary
phase
Not directly involved in the
normal growth, Role in defense
system
e.g. antibiotics, pigments,
toxins

6. 4. Recombinant products
Genes from higher organisms - introduced in microbial cells
Recombinant microbe- synthesize heterologous protein
E coli, S cerevisiae, filamentous fungi - insulin, interferon, human
serum albumin, factors VIII and IX, epidermal growth factor,
bovine somatostatin.

7. 5. Transformation processes
• Microbes behave as chiral catalysts
• convert a compound to more valuable compound
• Addition, removal or modification of functional groups at
specific sites on a complex molecule.
• Catalyze dehydrogenation, oxidation, hydroxylation,
dehydration and condensation, decarboxylation, amination,
deamination and isomerization.
• Operate at relatively low temperatures and pressures
• No need of heavy-metal catalysts
• Production of vinegar, steroids, antibiotics and prostaglandins

8. Component parts of a fermentation Process
6 basic components
1. Formulation of media – for inoculum and in production
fermenter
2. Sterilization of the medium, fermenters and ancillary
equipment
3. Production of inoculum
4. Growth of organism in fermenter under optimum conditions
5. Extraction and purification of product.
6. Disposal of effluents

9. Principles of fermentation technology, PF Stanbury, A Whittakker, SJ Hall, 1995, Butterworth-Heinemann publications

10. References
• Principles of fermentation technology, PF Stanbury, A Whittakker, SJ Hall
• Industrial microbiology –Casida L. E. J. R.