Principles of Processes of Biotechnology

The European Federation of Biotechnology (EFB) defined biotechnology as ‘the integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services.’

Modern biotechnology is based on two core techniques.

These are:

• Genetic engineering.
• Bioprocess engineering/chemical engineering/sterilisation methods.

Genetic engineering deals with the alteration of the chemistry of genetic material, that is, DNA and RNA, and their introduction into host organisms so that the phenotype of the host organism changes.

Bioprocess engineering involves maintaining sterile, microbial-contamination-free conditions so that only the desired microbe or eukaryotic cell grows in large quantities.

This is done to manufacture useful products such as antibiotics, vaccines, enzymes, antibodies, organic acids, vitamins, therapeutics, and hormones.

Genetic engineering is the manipulation of genetic material in a directed, predetermined way using in vitro processes to achieve a desired end.

It includes:

• Creation of recombinant DNA.
• Gene cloning.
• Gene transfer.

It helps isolate and introduce only one or a selected set of desirable genes into the target organism, without introducing undesirable genes.

Genetic Engineering Involves:

• Repairing defective genes.
• Replacing defective genes with healthy or normal genes.
• Artificially synthesising a totally new gene.
• Transfer of genes into a new location or into a new organism.
• Introducing new genes altogether.
• Combining genes from two organisms.
• Altering the genotype.
• Improvement of living organisms.
• Gene cloning.

Note: Genetic engineering is also called recombinant DNA technology. It is also called gene cloning.

• A piece of alien DNA transferred into another organism usually cannot multiply in the progeny cells on its own.
• If it integrates into the recipient's genome, it can replicate and be inherited along with the host DNA.
• This is because chromosomes can replicate.
• In a chromosome, there is a specific DNA sequence called the origin of replication.
• The origin of replication initiates replication.
• Therefore, for the multiplication of any alien piece of DNA, it must become associated with a DNA sequence having an origin of replication.
• When alien DNA is linked with the origin of replication, it can replicate and multiply in the host organism.
• Making multiple identical copies of a DNA template is called cloning.

• The first artificial recombinant DNA molecule was formed by linking a gene encoding antibiotic resistance with a native plasmid of Salmonella typhimurium.
• A plasmid is an autonomously replicating circular extrachromosomal DNA.
• This work was accomplished in 1972 by Stanley Cohen and Herbert Boyer.
• The antibiotic resistance gene was isolated by cutting out a piece of DNA from a plasmid responsible for conferring antibiotic resistance.

• DNA can be cut at specific locations by restriction enzymes.
• Restriction enzymes are called molecular scissors.
• The cut DNA fragment was linked with plasmid DNA.
• Plasmid DNA acts as a vector to transfer the attached DNA into the host organism.
• DNA ligase acts on cut DNA molecules and joins their ends.
• Joining the antibiotic resistance gene to the plasmid vector was made possible by DNA ligase.
• The new combination of circular autonomously replicating DNA formed in vitro is called recombinant DNA.

• When recombinant DNA is introduced into Escherichia coli, it replicates using the host DNA polymerase.
• As a result, multiple copies are produced.
• This multiplication of the antibiotic resistance gene in E. coli is called cloning of the antibiotic resistance gene in E. coli.

1. Identification of DNA with desirable genes.
2. Introduction of the identified DNA into the host.
3. Maintenance of the introduced DNA in the host and transfer of the DNA to its progeny.

• Two Core Techniques - Modern biotechnology is based on (i) Genetic Engineering and (ii) Chemical Engineering.
• Genetic Engineering - Deals with the alteration of DNA and RNA to achieve desired results in a directed, predetermined way using in vitro processes.
• Chemical Engineering - Maintains a sterile environment for manufacturing useful products like vaccines, antibodies, enzymes, vitamins, and therapeutics.
• What Genetic Engineering Involves - Repairing/replacing defective genes, synthesising new genes, transferring genes, combining genes from two organisms, and altering genotype.
• Other Names for Genetic Engineering - Also called Recombinant DNA (rDNA) Technology or Gene Cloning, as it involves transferring a gene via a suitable vector to a new location or organism.