Biological Reaction

8/10/2019 Biological Reaction

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SITI WAHIDAH BINTI PUASAPHONE NO: 03-55436327

011-32338927Reference: The Eng. Of Chemical

Reactions ( Schmidt)

Credit to: Pn. Norhasyimi, Pn.Sharmeela & Cik Faeqah

CPE624 Advanced Chemical Reaction Engineering

TOPIC 2Bio-reactors

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CPE624: ADVANCED CHEMICAL REACTION ENGINEERING

Biochemical reactions are characterized by the use ofenzymes or whole cells (micro-organisms) to carry outspecific conversions

Living organisms are capable ofcarrying out a wide range oftransformations which can often bemanipulated by controlling theirenvironment or by changing geneticconstitution. The primary interest oforganism is to replicate themselves

• Example:• Fermentation of fruit juices to make alcohol• Subsequent oxidation to vinegar




Major areas of biological sciences that are significance to the

process engineer.




Applications of biological processes will considering

systematics, genetics, biochemistry and physiology.

Outline of a biological process:




Important aspects to reactors:•

Nature and processing of raw materials• Choice and manipulation of the catalysts• Control of reaction process from which the product

must be recovered.

Bioprocesses are autocatalytic reactions . Cells is a group ofproteins that have catalytic properties (Enzymes)

Enzymes, similar to inorganic catalyst in some ways andvery powerful catalysts that capable to enhance the overallrate of reactions.




Enzymes are water-soluble but are frequently bound tomembranes within the cells or retained in the microbe bythe cell walls.

Enzymes usually retain their catalytic activity whenisolated from the cell

Bioreactors as an alternatives to conventional chemical

reactors, e.g in pharmaceutical industry, micro-organism& enzymes can be used to produce specific streo-isomersselectivity.


http://slidepdf.com/reader/full/biological-reaction 7/31CPE624: ADVANCED CHEMICAL REACTION ENGINEERING

Advantages

high selectivityFeasible for multistage separation in purificationReduced potential pollutionIncreased energy recovery and reduced greenhouse

emissions

Lower long-term maintenance cost

DisadvantagesProduct may formed in dilute aqueous solutionLow ratesRheological properties that difficult to handleLow interfacial tensions – difficulties in physical

separation of product









Organism must grow & reproduce itself using resources

from the surrounding environmentLiving systems capture & utilize energy from theenvironment to produce highly ordered structures to giverise to autocatalytic processes.

This allows the natural optimization of living processes forthe evolution of new biological information structures andnew life forms.

The complexity of the bacterial cell is thus a match forany chemical plant in the power and sophistication of itschemistry.



The basic of life lies in chemistry creates a variety ofnovel solutions to a set of problem associated with life.These includes:

The acquisition of food – provide energy and nutrientsthat make up the structure of the cellConversion of the food into the structure of the livingsystemRetention of information – chemical structures maybe reproduced when requiredIntroduction of variation in the biological information

- to encourage the adaptation of the organisms to theenvironment



6 majorelements,

make up 90%

of weight



Most of the elemental composition of cells is found in

proteins, nucleic acid and lipids.

Water is the major component of cells with 80 – 90% ofthe total weight

Most of the protein present in the form of enzymes.

Nucleic acid are found in various forms of Ribonucleic Acid (RNA) and Deoxyribonucleic Acid (DNA)

Polysaccharides and lipids are associated with wall &membrane structures & also act as energy-storagematerials within the cell.





Nucleic acid in the form of DNA forms the storedstructural and regulatory material for organism.

Protein is formed mainly of polymerised amino-acids.The primary structure is non-repetitive & require achemical template stored in DNA molecule for itsproduction.

Proteins have catalytic activity (enzymes) whilst other

proteins have roles in storage, trasportation, antibodies,chemical messengers (hormones) & in structure.



Nucleotides are the basic monomers of nucleic acid. It ismade from heterocyclic nitrogen compounds, purines &pyrimidines

Types of nucleic acid:

Ribonucleic acid (RNA)–

contain ribose with bases ofcytosine, adenine, guanine and a unique base uracil.Deoxyribonucleic acid (DNA) – contain deoxyribone

with bases of cytosine, adenine, guanine and a uniquebase thymidine.

The differences in the base structure affect the secondarystructures of these polymers.







Lipids – major components of membrane.

Complex structure of fatty acids esterified with alcohols toform glycerides

Sterols is also important lipid components

Hydophobic structure – provide entry & exit ports from

the interior of cell



Major structural components of the cell walls.

Cellulose is the most commom form.

Others – hemicellulose (hexose & pentose), pectins andchitin.

Also act as energy storage materials in living systems.

Glycogen & starch are the major carbohydrate stores inanimals & plants, respectively.



Derived from carbohydrates and polymeric materials.

Provide the cell with mechanical strength, provide rigidstructure againts which the membrane located.

The variable structure will change according toenvironment and surface properties are determined bythe cell wall materials.

The wall is negatively charges & can act as an ionexchanger.




Biological combustion

Oxygen transport

Photosynthesis

Genetic code




P n AnS n A P A s

A biological species i.e organism or cellsS substrate or food supplyP metabolic product

n A>1 organism growth (reproduction)n A=1 metabolism




Kinetics of Reproduction P AS A 2 S A

C kC r

If excess nutrient SOS C C

SO AC kC r




In batch reactor SO A A

C kC dt

dC

t kC

Ao A soeC C

exponential growthNatural for any living system to reproduceDesired exponential growth??Undesired exponential growth???




If growth is limited by food supply, S and Acan be related by

S

S SO

A

Ao A

n

C C

n

C C

1




A B B C k r

SO B kC k

2

AC k r D D

What is the reaction rate model for population whichincludes birth and death?

Model for steady state population; birth and death




Metabolism A is not reproducing, therefore n A =1

P AS A S A

C kC r

P S

CA is constant, AO A C C




In batch reactor, S Ao

S C kC dt

dC

t kC

SoS

Ao

eC C

P S SO C C C Material balance

)1( t kC

So P AoeC C



Kinetics is the study of the rated of chemical reactions.

The rates of biological reactions are greatly increased byenzyme catalysts.

Enzyme kinetics is based upon the elementary kinetics.

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Biological Reaction

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