This document discusses biocatalysts and enzymes. It begins by listing five properties of useful industrial microbes, such as producing spores or being amenable to genetic manipulation. It then defines biocatalysts as enzymes or microbes that accelerate chemical reactions. Enzymes function as biocatalysts by lowering the activation energy of reactions. The document outlines the structure and function of enzymes, including their active sites, and compares enzymes to non-biological catalysts. It also discusses producing biocatalysts through fermentation and engineering enzymes to modify their properties.

1. Biotechnology
BIOC 22642
Dr. Chamila Kadigamuwa
25/01/2023
Lecture # 2

2. Quiz # 1
2. Name five (5) properties of useful industrial microbes ?

3. • Produces spores or can be easily inoculated
• Grows rapidly on a large scale in inexpensive medium
• Produces desired product quickly
• Should not be pathogenic
• Amenable to genetic manipulation
Properties of useful industrial microbes

4. How to increase the rate of a reaction:
1. Increase the concentration of a reactant.
2. Increase the temperature of the reactants.
3. Increase the surface area of a reactant.
4. Add a catalyst to the reaction.

5. • A catalyst is a substance which alters to promote the reaction, and a
substance especially an enzyme, that initiates or modifies the rate of
a chemical reaction in a living body is termed as biocatalyst.
• They are enzymes or microbes that initiate or accelerate chemical
reactions
• How enzyme can accelerate chemical reactions?
Enzymes as Biocatalysts

6. Effect of biocatalyst on activation energy

7. • Enzymes are chemical substances which are mostly proteins.
• Enzymes catalyze nearly all the biochemical reactions in the living cells.
• They have unique three dimensional shapes that fits the shape of reactants
• Enzymes are typically derived from plants, micro-organisms (yeast, bacteria or
fungi) or animal tissue (e.g. protease from pancreas).
Enzymes as Biocatalysts cont’d

8. Enzymes
Lower a
Reaction’s
Activation
Energy

9. Enzymes vs. Nonbiological catalysts

10. Enzymes vs. Nonbiological catalysts
Feature Enzyme Nonbiological catalyst
Structure Proteins Varies from metal ions to
complex molecules
Mode of action Catalysis occur via active
site
Catalysis takes part as a
whole
Specificity Highly specific Less specific/ can catalyze
different reactions
Saturation Can be saturated with
substrate
Most do not show
saturation
Sensitivity to
temperature & pH
Have optimum condition Not sensitive
Nature Generally produced by
living cells & acts inside
living cells
Reacts out side the living
cells

11. Enzyme structure
• Enzymes are proteins
which are chains of
amino acids.
• They are folded into a
complex 3-D structure.
• So they have a globular
shape.
• Their shape determine the
enzyme’s function.
Human pancreatic amylase

12. The active site

13. The active site cont’d
• The area on the enzyme where the substrate or
substrates attach to is called the active site.
• Enzymes are usually very large proteins and the active
site is just a small region of the enzyme molecule.

14. •Folded protein structure determine
the function of enzyme.

15. How enzyme work
https://www.youtube.com/watch?v=yk14dOOvwMk

16. Types of biocatalysts
• Microbes: e.g. yeast, and other anaerobic bacteria.
• Lipases: These are the most widely used class of enzymes in organic
synthesis, they are preferred widely because of their better stability
as compared to others.
• Proteases: Enzymes which break down proteins.
• Cellulases: Enzymes which break down cellulose.
• Amylases: which break down starch into simple sugars.

20. Types of enzymes depend on the function

23. Production of Biocatalists (Enzymes)
• Commercial sources of enzymes are obtained from three primary sources,
i.e. animal tissue, plants and microbes.
• These naturally occurring enzymes are quite often not readily
available in sufficient quantities for food applications or industrial use.
• However, by isolating microbial strains that produce the desired enzyme
and optimizing the conditions for growth, commercial quantities can be
obtained.

24. Why we use enzymes for industries?
• Enzymes speed up chemical reactions in a natural way.
• As they are not alive, they remain as inert mass of proteins.
• Enzymes work by weakening bonds which lowers activation energy.

26. Merits of using biocatalysts for industries

27. Enzyme engineering
• The process of improving the efficiency of an already
available enzyme or the formulation of an
advanced enzyme activity by altering its amino acid
sequence through the genetic engineering techniques.

28. Objectives
• Suitability for use in organic
solvents
• Modification of substrate
specificity
• Increased stability to oxidizing
agents
• Improved stability to heavy
metals
• Resistance to proteolytic
degradation
• Fusion of two or more enzymes
to create bi- and poly functional
enzymes

29. Steps involved in enzyme engineering

30. 1) Isolation of the concerned enzyme and
determination of its structure and properties.
2) The obtained data are analyzed together with the
known database.
3) Molecular modeling is performed to determine a
possible change in amino acid sequence.
4) Constructing a gene that will encode the amino acid
sequence specified at step 3.
5) Once the appropriate gene is constructed, it is
introduced and expressed in a suitable host, e.g. E.
coli.
6) The produced recombinant or mutant enzyme is
isolate, purified and used for determination of its
structure and faction.

31. Strategies for enzyme engineering

33. Application of enzyme engineering

34. Enzyme engineering
• Alteration of gene sequence to modify properties of gene product
(protein/enzyme)
• Amino acid replacement
Change codon nucleotides to give different amino acid
• Deletion mutant
Delete an amino acid by removing triplet codon
• Addition mutant
Insert new amino acid by adding triplet codon

35. Reasons for Enzyme Engineering
•Enhance protein thermostability
 Usually by inserting new intramolecular interactions such as covalent disulphide
(S-S) bonds or non-covalent salt bridges.
•Reduce oxidation sensitivity
 By deletion/replacement of oxidation sensitive amino acid residues (e.g., cysteine)
•Alter enzyme substrate specificity
 By altering the size and shape of the active site (e.g., by removing bulky side
chains)
•Increase catalytic activity
 By changing the environment of the active site (by random mutagenesis and
selection)

36. mRNA codon Amino acid Mutated codon New amino acid
Type of mutation/Result
of mutation
GCU Ala GCC Ala
Degenerate
codons/no change
GCU Ala GAU Asp
Amino acid
change/addition of
charged group
UCA Ser UGU Cys
Insertion of cysteine
(e.g., for S-S bond
formation)
UUG Phe GGG Gly
Removal of bulky
side chain
GAU Asp GAA Glu
Change in side chain
size with retention of
charge
Examples of simple mutations

37. Bioprocess Technology

38. Liquid Fermentation Systems
•The types of fermenter ranges from simple tank to
complex integrated system of automated control.
•Most fermentations use liquid media
•Some are non stirred, non aerated and non
aseptically operated (beer, wine) while others are
stirred, aerated and aseptic

39. Biotechnological process that involve the growth of
microorganisms on solid substrate in the absence or near
absence of water.
Solid fermentation Systems

40. Bioreactor / Fermenter
• Bioreactor is a vessel for the growth of microorganisms ( fermentation).
• Bioreactors provide the aseptic condition for fermentation by not
permitting contamination.
• A bioreactor can be defined as an apparatus, such as a large
fermentation chamber, for growing organisms such as bacteria or yeast
that are used in the biotechnological manufacture of substances such
as pharmaceuticals, antibodies, or vaccines, or for the bioconversion of
organic waste.