Introduction :-

• Biotechnology deals with the techniques of using living organisms or enzymes or enzymes from organisms to produce products useful to humans.
• The term ‘Biotechnology’ was given by Karl Ereky (1919).
• According to European federation of biotechnology (EFB),biotechnology is the integration of natural science and organism, cells, parts thereof, and molecular analogues for products and services.

Principles of biotechnology

The two core techniques that developed moderns technology are :
i) Genetics engineering which is modification of chemical nature of DNA/RNA and their introduction into another host organism to change the phenotypic characters of the host.
ii) Sterilisation method to maintain growth and manipulation of only the desired microbes or cells in large quantities, for the manufacture of biotechnology products like antibiotics, vaccines, enzymes, etc.

The basic steps in genetic engineering include :

(i) Identification of DNA with desirable genes.
(ii) introduction of the DNA into host to form recombinant DNA (rDNA)
(iii) maintenance of DNA in host and gene cloning.
(iv) Gene transfer.

In 1972 , stanley cohen and herbert boyer constructed the first recombinant DNA.

Steps carried out in constructing first recombination DNA.

(i) A gene encoding antibiotic resistance in the native plasmid of salmonella typhi murium v. was identified, plasmid is an autonomously replicating circular extra-choroosmal DNA.
(ii) the desired DNA was cut at specific locations by restriction enzymes.
(iii) the cut DNA was linked to plasmid DNA and transferred to E.coli for gene multiplication.

Important tools of recombinant DNA technology are –

• Restriction enzymes-
  Restriction enzymes are called as molecular scissors because these enzymes cut DNA at specific sites.
• Cloning vector –
  Plasmids and bacteriophages have the ability to replicate within bacterial cells independent of the control of chromosomal DNA.
• Competent host –
  The host should be competent enough to take up the foreign DNA.
• Bioreactors –
  Bioreactor is the cylindrical vessel in which biological processes is carried out on a large scale.