biological reaction naj

CPE624

Advanced Chemical Reaction Engineering

TOPIC 2 Bio-reactors

CPE624: ADVANCED CHEMICAL REACTION ENGINEERING

Biochemical reactions are characterized by the use of enzymes or whole cells (micro-organisms) to carry out specific conversions

Living organisms are capable of carrying out a wide range of transformations which can often be manipulated by controlling their environment or by changing genetic constitution. The primary interest of organism 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 of proteins that have catalytic properties (Enzymes)

Enzymes, similar to inorganic catalyst in some ways and very powerful catalysts that capable to enhance the overall rate of reactions.


Enzymes are water-soluble but are frequently bound to membranes within the cells or retained in the microbe by the cell walls.

Enzymes usually retain their catalytic activity when isolated 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-isomers selectivity.


Advantages high selectivity Feasible for multistage separation in purification Reduced potential pollution Increased energy recovery and reduced greenhouse emissions Lower long-term maintenance cost

Disadvantages Product may formed in dilute aqueous solution Low rates Rheological properties that difficult to handle Low interfacial tensions difficulties in physical separation of product


Each components are divided by bilayer phospholipids membranes.

Transportation of reactants & products to & from cells produces concentration gradients because of transport resistances within & without the cell.


Organism must grow & reproduce itself using resources from the surrounding environment

Living systems capture & utilize energy from the environment to produce highly ordered structures to give rise to autocatalytic processes.

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

The complexity of the bacterial cell is thus a match for any chemical plant in the power and sophistication of its chemistry.


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

The acquisition of food provide energy and nutrients

that make up the structure of the cell Conversion of the food into the structure of the living

system Retention of information chemical structures may

be reproduced when required Introduction of variation in the biological information

- to encourage the adaptation of the organisms to the environment


6 major

elements, 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 8090% of the 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-storage materials within the cell.


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

Protein is formed mainly of polymerised amino-acids. The primary structure is non-repetitive & require a chemical template stored in DNA molecule for its production.

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 is made from heterocyclic nitrogen compounds, purines & pyrimidines

Types of nucleic acid:

Ribonucleic acid (RNA) contain ribose with bases of cytosine, adenine, guanine and a unique base uracil. Deoxyribonucleic acid (DNA) contain deoxyribone with bases of cytosine, adenine, guanine and a unique base thymidine.

The differences in the base structure affect the secondary structures of these polymers.


Lipids major components of membrane.

Complex structure of fatty acids esterified with alcohols to form 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 and chitin.

Also act as energy storage materials in living systems.

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


Derived from carbohydrates and polymeric materials. Provide the cell with mechanical strength, provide rigid structure againts which the membrane located. The variable structure will change according to environment and surface properties are determined by the cell wall materials. The wall is negatively charges & can act as an ion exchanger.

CPE624

Advanced Chemical Reaction Engineering

Dr Najmiddin Yaakob 03-55448006

[email protected]


Biological combustion Oxygen transport Photosynthesis Genetic code


PnAnSnA PAs

Abiological species i.e organism or cells Ssubstrate or food supply Pmetabolic product nA>1 organism growth (reproduction) nA=1 metabolism


Kinetics of Reproduction

PASA 2 SACkCr

If excess nutrient SOS CC

SOACkCr


In batch reactor SOA

A CkCdt

dC

tkC

AoAsoeCC

exponential growth Natural for any living system to reproduce Desired exponential growth?? Undesired exponential growth???


Metabolism A is not reproducing, therefore nA=1

PASA SACkCr

PS

CA is constant, AOA CC


In batch reactor, SAoS CkC

dt

dC

tkC

SoSAoeCC

PSSO CCC Material balance

)1(tkC

SoPAoeCC


Kinetics is the study of the rated of chemical reactions. The rates of biological reactions are greatly increased by

enzyme catalysts. Enzyme kinetics is based upon the elementary kinetics.

biological reaction naj

Documents

chemical plant

conventional chemical

bioreactors cpe624

use of enzymes

microorganism enzymes

autocatalytic processes

cells microorganisms

cell bioreactors