It briefs the roles of microbes in industry

1. Chapter 3
Application of microbes in industrial
biotechnology

2. Mixed acid
fermentation

3. 3.1. Organic acid production
o Principal constituent of vinegar.
o The first vinegar was spoiled wine,
o Consisting the Latin word acetum means sour or
sharp wine.
o Produced by acetic acid bacteria
o These Gram-negative bacteria Acetobacter, Asaia,
Acidomonas, Gluconobacter, Gluconacetobacter,
and Kozakia.
o With the exception of Asaia, they produce large
quantities of acetic acid from ethanol, and can grow
in the presence of 0.35% acetic acid
1. Acetic Acid

4. ANAEROBIC PROCESS

5. 2.Lactic Acid
 Lactic acid (LA) is
 Catabolic products of Primary metabolism by
microbes
 Mainly produced by lactic acid bacteria
 A lactic starter is a basic starter culture with
widespread use in the dairy industry.
 For cheese making of all kinds, lactic acid
production is essential, and the lactic starter is
employed for this purpose.

6. THE LACTIC ACID BACTERIA (LAB)
 They are formicates group, non-spore
forming, Rods or cocci shaped.
 Carnobacterium Oenococcus
Enterococcus
Pediococcus Paralactobacillus
Lactobacillus Streptococcus
Lactosphaera Tetragenococcus
Leuconostoc Vagococcus
Lactococcus
 Grow anaerobically but are not killed by
oxygen. (as is the case with many
anaerobes).
 They obtain their energy from sugars and are
found in environments where sugar is

7. Lactic Acid Bacteria Into Two Major
Groups
 HOMOFERMENTATIVE GROUP : Produce lactic acid as
the sole product of the fermentation of sugars.
 HETEROFERMENTATIVE GROUP : Besides lactic acid also
produce ethanol, as well as CO2.

8. Choice of a Particular Lactic Acid Bacterium
Lactic Acid Bacterium Is Able to Ferment
Lactobacillus delbreuckii
subspecies delbreuckii
Sucrose
Lactobacillus delbreuckii
subspecies bulgaricus
Lactose
Lactobacillus helveticus Both lactose and galactose
Lactobacillus amylophylus and
L. amylovirus
Starch
Lactobacillus lactis Glucose, sucrose and
galactose
Lactobacillus pentosus Sulfite waste liquor

9. PRODUCTION OF LACTIC ACID
 The organisms responsible for the production of
lactic acid includes
 Bacteria : Lactobacillus helveticus, L. salivarus. L. brevis. L viridescens.
L. plantarurn and Pediococcus damnosus.
 Fungi : Candida krusei, Saccharomyces cerevisiae, Rhizopus sp,
 It requires only a simple medium and produces L (+) lactic acid. It
also requires vigorous aeration.
 Rhizopus sp : Utilize glucose aerobically to produce lactic acid.
 Rhzopus species such as R. oryzae and R. arrhizus have
amylolytic enzyme activity, which enables them to convert starch
directly to L (+)-lactic acid.
 In fungal fermentation, the low production rate
 The lower product yield from fungal fermentation is attributed partially to
the formation of by-products, such as fumaric acid and ethanol.

10. 3.Citric acid production
In 1917, James Currie discovered certain strains of the mold Aspergillus
niger could be efficient citric acid producers,

11. Citric Acid Production by Aerobic Bioprocesses

12.  Microorganism: Aspergillus niger (mainly), Candida yeast (from
carbohydrates or n-alkanes)
 Citric acid production is mixed growth associated, mainly take place
under nitrogen and phosphate limitation after growth has ceased.
 Medium requirements for high production:
- Carbon source: molasses or sugar solution.
- Na-ferrocyanide is added to reduce Iron and manganese.
- High dissolved oxygen concentration
- High sugar concentration
- pH<2
- Temperature: 30oC
Industrial Production of Citric acid

13. 3.2. Amino Acid production by
Fermentation
 Amino acids
 Used as feed additives in the food industry
 Used as nutritional supplements in nutraceutical
industry
 Used as starting materials in the chemical industry
 Examples include
 Glutamic acid
 Aspartic acid and phenylalanine
 Lysine
 Methionine
• All produced by process of fermentation used to be
produced by chemical synthesis
• Amino acids (glutamic acid) production was primary
produced by Japanese scientists

14. Glutamic Acid Fermentation
1. Media
o Carbon glucose, the acid hydrolysate of starch, molasses, or a
mixture of these substances.
o Nitrogen source: urea
2. Microorganism
 First Micrococcus glutamicum
 Now a days Coryneform sp
 Others are Brevibactirium
3. pH, temperature, and aeration rate
4. The fermentation broth is hydrolyzed with hydrochloric
acid.

15.  The metabolic pathway for biosynthesis of L- glutamic
acid GLUCOSE -->ACETYL Coa CITRIC ACID Alpha
ketoglutaric acid
 AMINATION: GLUTAMATE DEHYDROGENASE
(M.Glutamicus possesses this enzyme) L –GLUTAMIC
ACID

16. Aspartate Aspartate
semialdehyde
Diaminopimelate
Aspartyl-P
Methionine
Threonine
Isoleucine
Feedback
inhibition
ATP
Lysine
Lysine:
AEC:
Aspartokinase

17. Sources of Enzymes
Biologically active enzymes may be extracted from
any living organism:
Of the hundred enzymes being used industrially,
- over a half are from fungi
- over a third are from bacteria with the
remainder divided between animal (8%) and
plant (4%) sources .
3.3. Production of enzymes

18. Sources f Enzymes
Microbes are preferred to plants and animals as
sources of enzymes because:
- They are generally cheaper to produce.
- Their enzyme contents are more predictable and
controllable.
- Plant and animal tissues contain more potentially
harmful materials than microbes, including
phenolic compounds (from plants).

19. Enzyme EC Sources Application
a-Amylase 3.2.1.1 Aspergillus E Baking
Catalase 1.11.1.6 Aspergillus I Food
Cellulase 3.2.1.4 Trichoderma E Waste
Dextranase 3.2.1.11 Penicillium E Food
Glucose oxidase 1.1.3.4 Aspergillus I Food
Lactase 3.2.1.23 Aspergillus E Dairy
Lipase 3.1.1.3 Rhizopus E Food
Rennet 3.4.23.6
Mucor
miehei
E Cheese
Pectinase 3.2.1.15 Aspergillus E Drinks
Protease 3.4.23.6 Aspergillus E Baking
E: extracellular enzyme; I: intracellular enzyme
Fungal Enzymes

20. Enzyme Sources Application
a-Amylase 3.2.1.1 Bacillus E Starch
b-Amylase 3.2.1.2 Bacillus E Starch
Asparaginase 3.5.1.1
Escherichia
coli
I Health
Glucose
isomerase
5.3.1.5 Bacillus I
Fructose
syrup
Penicillin
amidase
3.5.1.11 Bacillus I
Pharmace
utical
Protease 3.4.21.14 Bacillus E Detergent
Bacterial Enzymes

21. Enzyme Production

22. 3.4. Microbial transformation
 Biotransformations are structural modifications in a
chemical compound by organisms /enzyme systems
that lead to the formation of molecules with relatively
greater polarity.
 This mechanism has been developed by microbes to
acclimatize to environmental changes and it is useful
in a wide range of biotechnological processes.
 The most significant aspect of biotransformation is that
it maintains the original carbon skeleton after
obtaining the products

23. Biotransformation is of two types:
1. Enzymatic: Microsomal biotransformation is caused by enzymes
present within the lipophilic membranes of smooth endoplasmic
reticulum .
2. Nonenzymatic: Non-Microsomal Biotransformation involves the
enzymes which are present within the mitochondria
BIOTRANSFORMATION REACTION
Any structural change in a molecule
Phase I - creates site for phase II reaction
o Oxidation (adds O) e.g. microsomes
o Reduction
o Hydrolysis (e.g. by plasma esterases)
o Others
Phase II - couples group to existing (or phase I formed) conjugation
site
o Glucuronide (with glucuronic acid)
o Sulphate
o Others

24. Microbial cells are ideal choice for
biotransformation due to certain reasons like:
I. Surface-volume ratio: Microbial biotransformation
has high surface-volume ratio.
II. Growth Rate: Higher growth rate of microbial cells
reduces the time of biomass transformation.
III. Metabolism Rate: Higher rate of the metabolism in
microbes leads to efficient transformation of substrate.
IV. Sterility: It is easier to maintain sterile conditions
when microbes are used

25. Applications of Microbial Biotransformation
 Transformation of steroids and sterols.
 Transformation of Pollutants.
 Transformation of Non-Steroid Compounds.
 Transformation of Antibiotics.
 Transformation of Pesticides.
 Petroleum Biotransformation.

26. Example of microbial biotransformation
Oxidation
Halogenation