Introduction

Biotechnology may be defined as "the application of scientific and engineering principles to the processing of materials by biological agents to provide goods and services" (OECD, 1982). The earliest examples of biological processing include the production of fermented foods and beverages, even though they pre-date any understanding of the nature of the biological agents or the scientific principles involved. The early history of biotechnology is therefore immersed in the history of the food industry. Today, the food industry is the biggest user of bulk enzymes, accounting for 50% of world sales (Harlander, 1989). It can therefore claim to have a substantial interest in commercial biotechnology. The scope and value of enzyme use in the food industry is shown by the data in Table 1.

In recent years, a rapid expansion has taken place in biotechnology, brought about by a substantial increase in knowledge of the biochemistry and physiology of living organisms and their control. In particular, the elucidation of the structure of DNA and the genetic code, and the development of the means of genetic manipulation have given unprecedented potential for the industrial exploitation of living systems.

Biological processes are a particularly attractive means of carrying out industrial syntheses and transformations. As enzyme-catalysed reactions are highly specific, they are less likely than equivalent chemical processes to produce side products. Enzymes or whole cells can often carry out in a single step complex chemical reactions which would require several steps if carried out by conventional means. In addition, such reactions usually occur under mild conditions of temperature, pressure and pH. There exists in nature thousands of enzymes which catalyse the different biochemical reactions involved in the metabolism of all living organisms. This represents a vast pool of potential industrial catalysts. The techniques of genetic manipulation now make it possible for many of these enzymes to be produced on a large scale by well-characterised industrial cell systems. Methods of "protein engineering" are also being developed which enable the structure and function of enzymes to be manipulated by site-specific mutagenesis to improve their suitability for industrial use (Goodenough & Jenkins, 1991; Pickersgill & Goodenough, 1991).

Table 1

The use of enzymes by the food industry

(Data from Pilnik & Voragen, 1990)

Industry

Enzymes

Million US $

Sugar & Starch Industry a-Amylase

Glucoamylase

Isomerase

Pullulanase

Isoamylase

Oligoamylases

Cycloglucosyl transferase

Xylanase

0 0

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