13.1 Introduction

Biotechnology was originally an entirely empirical process, pursued by human societies for many millennia. This classical form of biotechnology involved the creation of new products by harnessing biological systems, most particularly microbial fermentation. The raw materials for such biotechnological conversions were either naturally growing plants or, more commonly, were obtained from agricultural crops or livestock. Animal or microbial extracts were used to convert milk from cows, sheep, goats etc. into foodstuffs like cheese or yoghurt, while yeasts were used to make leavened bread from wheat flour. The poor quality of drinking water, particularly in urban areas, made it desirable to consume fermented drinks as a safer alternative beverage. Extracts of any sugar-containing raw material, including most fruits, grains and animal milks, could be used in conjunction with yeasts to produce a wide range of such alcoholic liquors. For example, malted barley can be made into beer, grapes into wine, rice into saki and yak's milk into chang. During the past fifty years, biotechnology has gradually come to have a rather different meaning, namely the scientific application of modern biological techniques, such as recombinant DNA technology, for...