Microbial fermentation involves microorganisms like yeast and bacteria breaking down substances and converting them into simpler products. Fermentation is used to produce foods and beverages like beer, wine, bread, and yogurt. The document discusses fermentation processes like the types of fermenters used, fermentation media composition, inoculation, and techniques. Some important fermentation products mentioned are ethanol, lactic acid, enzymes, and cheeses. Challenges in microbial fermentation can include bacterial, viral, and fungal contamination that reduce yields and productivity.

1. MICROBIAL FERMENTATION
ROMANCE MANNA

2. INTRODUCTION
• Fermentation is the process in which a substance breaks down into a simpler
substance. Microorganisms like yeast and bacteria usually play a role in the
fermentation process, creating beer, wine, bread, yogrut and otherfoods
Fermentation comes from the Latin word fermentare, meaning ‘to leaven.’

3. What is fermentation?
 Pasteur’s definition: “Life without air”,
anaerobe red ox reactions in organisms.
 New definition: A form of metabolism in
which the end products could be further
oxidized .
 For example: A yeast cell obtains 2 molecules
of ATP per molecule of glucose when it
ferments it to ethanol.

4. What is fermenter & its types
 The heart of the fermentation process is the fermenter.
TYPES: Simple fermenters (batch and continuous)
Fed batch fermenter
Air-lift or bubble fermenter
Cyclone column fermenter
Tower fermenter
The size is few liters (laboratory use)
>500 m3 (industrial applications)

5. Fermentation medium
 Define medium :- nutritional, hormonal, and
substratum requirement of cells.
 In most cases, the medium is independent of the
bioreactor design and process parameters.
 The type: complex and synthetic medium (mineral
medium).
 Even small modifications in the medium could change
cell line stability, product quality, and downstream
processing.

6. MEDIUM COMPOSITION
Fermentation medium consists of:
 Macronutrients (C, H, N, S, P, Mg sources water,
sugars, lipid, amino acids, salt minerals)
 Micronutrients (trace elements/ metals, vitamins)
 Additional factors: growth factors, attachment proteins,
transport proteins, etc) For aerobic culture, oxygen is
sparged.

7. INOCULUMS
A small amount of substance containing bacteria from
a pure culture which is used to start a new culture.
Inoculum is prepared for the inoculation before the
fermentation starts.
It needs to be optimized for better performance:
 Adaptation in the medium.
 Mutation (DNA recombinant, radiation, chemical
addition).

8. FERMENTATION TECHNIQUES
Techniques for large-scale production of
microbial products. It must both provide an
optimum environment for the microbial
synthesis of the desired product and be
economically feasible on a large scale.
They can be divided into surface (emersion)
and submersion techniques

9. Fermentation techniques 1
Surface/Emersion technique
 In the surface techniques, the microorganisms are
cultivated on the surface of a liquid or solid substrate.
These techniques are very complicated and rarely used in
industry

10. Fermentation techniques 2
Submersion processes,
 The microorganisms grow in a liquid medium. Except
in traditional beer and wine fermentation, the
medium is held in fermenters and stirred to obtain a
homogeneous distribution of cells and medium.
Most processes are aerobic, and for these the
medium must be vigorously aerated. All important
industrial processes (production of biomass and
protein, antibiotics, enzymes and sewage treatment)
are carried out by submersion processes.

11. Some important fermentation products
Product Organism Use
Ethanol Saccharomyces cerevisiae Industrial solvents, beverages
Glycerol Saccharomyces cerevisiae Production of explosive
Lactic acid Lactobacillus bulgaricus Food and pharmaceutical
Acetone and butanol Clostridium
acetobutylicum
Solvents
α-amylase Bacillus subtilis Starch hydrolysis

12. Some important fermentation products
Amasi : fermented milk that
tastes like cottage cheese or plain
yogurt. Traditionally prepared by
storing unpasturized cow's milk in
a calabash container or hide sack
To allow it toferment.

13. WINE : Wine is an alcoholic drink
made from fermented grapes. Yeast
consumes the sugar in the grapes and
converts it to ethanol, carbon dioxide,
and heat. Different varieties of grapes
and strains of yeasts produce different
styles of wine.

14. CALPIS : An uncarbonated soft drink,
manufactured by Calpis Co., Ltd.
that is produced using
lactic acid fermentation

15. CHEESE: It is a dairy product derived from milk
that is produced in a wide range of flavors,
textures, and forms by coagulation of the milk protein
casein. It comprises proteins and fat from milk,

16. WINE MAKING FERMENTOR

17. Problems faced in microbial fermentation

18. Bacterial contamination
 This is the most common type of contaminant in
bacterial cultures. In all cases, one may expect reduced
yield of product, and possible contamination by
metabolites of contaminating bacteria
 In some cases toxins may be produced by contaminants
 The probability of occurrence of a particular type of
contaminations caused by bacteria may differ, depending
on the organism used in the process

19. Virus contamination
 Viruses are the most dangerous contaminant in this type
of fermentation.
 Due to small sizes, they are the toughest enemy to
prevent entering the process, and their occurrence may
result in very long lasting even several months,
paralysis of whole facility productivity.

20. Fungal infection
 Fungal cultures can be contaminated
also by other fungi. As this type of
contamination may be relatively hard to
detect, good measures of precaution
should be undertaken to prevent it.

21. Thank
you