l Another approach involves targetted gene transfer. It uses
homologous recombination to replace the endogenous gene
with the functional introduced gene. It may be used either to
inactivate a functional endogenous gene or to correct a
defective one.Applications of Industrial Biotechnology
l When an organic compound is modified by chemically defined
reactions, catalysed by enzymes present in cells, into a product
that is recoverable is called biotransformation. It is performed
by microbes, plants as well animal cells. Both the substrate and
the product are not involved in primary or secondary
metabolism of organism employed.
l Biotransfromation is routinely used for commercial production
of several useful antibiotics. Semisynthetic antibiotics,
e.g. semisynthetic penicillin and cephalosporins are produced
by chemical modification of penicillin nucleus, i.e.
6-aminopenicillanic acid.
l Steroid biotransformation is the most important microbial
process yielding pharmaceuticals including adrenocortical
hormones, e.g. corticosterone, cortisone and hydrocortisone,
other therapeutic derivatives as prednisone, triamcinolone, etc.
l Microbes are employed to recover valuable metals from low
grade ores and from dilute solutions for which conventional
metallurgical processes are uneconomical. The process is
referred to as bio-leaching or microbial ore leaching.
l The process involves bacteria mainly Thiobacillus ferrooxidans
which in duces leach ing of metal sul phate from low grade ores
con tain ing in sol u ble metal sulphides, e.g. cop per or iron, zinc,
etc. It re quires ex tremely low pH for growth and ac tiv ity and
de rives en ergy by oxi dis ing metal sulphides.Applications of Environmental Biotechnology
l The use of biological agents or their components to convert relatively
diffuse and inconvenient to use sources of energy (e.g. bio mass and
sun light) into more en ergy dense and con ve nient to use fu els such as
meth ane, ethanol, butanol, biodiesel and hydrogen, constitutes
Fuel Biotechnology. Such biologically produced fuels are called biofuels.
l Plant species that are efficient users of solar energy for converting CO
2
into biomass which can be used as a source of energy called energy
crops.
l The biomass may be available in the form of wood (lignocellulose)
e.g. Butea monosperma, casuarina, Eucalyptus, Melia and Tamarix
diocia, etc produce firewood.
l Starch, e.g. cereals, millets, root, tuber crops produce bioethanol.
l Sugar, e.g. sugarcane and sugarbeet also produce bioethanol.
l Hydrocarbons, e.g. Euphorbia lathyris, Asclepia, Copaifera, algae, etc.
proudce biodiesel.
l Hydrogen, e.g. algae like Chlamydomonas, bacteria like Clostridium is stored
as metal hydride and produce hydrogen which is a pollution free fuel.
l Superbug is a modified strain of oil eating bacteria developed by
prof. Anand M. Chakraborty. The process of working of these GMOs
which clean up several contaminants from the environment is called
bioremediation.
l Biodegradation is the chemical dissolution of materials by bacteria,
fungi or other means. It is different from the process of decomposition
occurring naturally. It is usually done for vast range of organic
compounds including hydrocarbons, polyaromatic hydrocarbons,
antibiotics, xenobiotics, etc.
l The compounds that resist biodegradation and persist in the
environment are called recalcitrants.AIPMT 2016
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