Environmental Engineering Reference
In-Depth Information
Chapter II
B
IOTECHNOLOGICAL
P
LATFORMS
A.
G
ENETIC
E
NGINEERING
1. Introduction
The diversity of biological activity and biological products offered by nature is a great
resource for biotechnology; inevitably, however, the limits of natural products or activities are
eventually found, and ways are sought to improve them. In these cases, either the
environment can be manipulated (as in bioreactors, described separately) or the organism
itself can be manipulated physiologically or genetically. The possibilities offered by genetic
engineering have grown dramatically in recent decades, and it is currently possible to alter the
capabilities of organisms, especially of microbes and plants, such that they exhibit activities
and generate products vastly different from those of their genetic precursors. While a
thorough review of current genetic engineering technology is beyond the scope of this report,
it is nevertheless useful to consider the methods most widely utilized in the development of
biofuels and bioplastics. These methods include:
•
The cloning of key genes (regions of deoxyribonucleic acid (DNA) that encode
enzymes) so that they may be moved and changed at will;
•
The detection of gene expression patterns by microarray analysis (facilitating the
controlled expression or over-expression of desired genes in native or heterologous
hosts);
•
The corresponding deletion or repression of expression of undesired genes;
•
The use of genomic techniques to predict functions of genetic loci;
•
The mutagenesis of genes to provide variants with altered activities, specificities,
environmental sensitivities, etc.; and
•
The integration of the above methods to construct new biosynthetic pathways.
2. State of the Science
2.1. Cloning and Sequencing
The “cloning” of a gene refers to the physical isolation of a sequence of DNA that
encodes a complete polypeptide in a form that can be replicated and manipulated easily.
