Biotechnology is one of those difficult terms that can mean different things to different people. In essence, it is the use of an organism (usually a microorganism) or a biologically derived substance (usually an enzyme) in a production or conversion process. Thus brewing and wine-making, food processing and manufacture, the production of pharmaceuticals and even the treatment of sewage can all be classed as aspects of biotechnology. In many cases the organism or enzyme is used in its natural form, and is not modified apart from perhaps having been subjected to selection methods to enable the best strain or type of enzyme to be used for a particular application. However, despite its traditional roots, modern biotechnology is often associated with the use of genetically modified systems. In this chapter we will consider the impact that gene manipulation technology has had on some biotechnological applications, with particular reference to the production of useful proteins.

The products of biotechnological processes are destined for use in a variety of fields such as medicine, agriculture and scientific research. It is perhaps an arbitrary distinction to separate the production of a therapeutic protein from its clinical application, as both could be considered as ‘biotechnology’ in its broadest sense. In a similar way, the developing area of transgenic plants and animals is also part of biotechnology, and undoubtedly the information provided by genome sequencing will give rise to many more diverse biotechnological applications.