Preface The BIOTOL series of texts are designed to provide a self-study resource concerning the principles, practices and applications of biotechnology. This text is designed to explain how biotechnology may be applied to solve problems encountered in the production and use of organic chemicals in a wide range of business sectors. Although the success of the organic industry is undoubted, conventional industrial organic chemical enterprises are faced with two main problems. Firstly, there are limitations on the specificity of reactions that can be carried out by purely chemical processes. This reduces yields of desirable products and frequently generates harmful by-products. Secondly, many reactions are camed out under conditions, and via mechanisms, that are energy demanding and incompatible with living systems. Furthermore elements are often used in concentrations and in combinations with other elements in ways not encountered in living systems. The outcome is that purely chemical processes often require complex and expensive purification procedures, generate materials that are recalcitrant to degradation and, in many instances, are toxic to living systems. Although recalcitrance may, in some cases, be desirable, for example in producing insulation materials for electrical devices, it is often undesirable leading to accumulation of non-biodegradable end products and the removal of material from natural geoqcling processes. It is for these reasons that the chemical technologies are often regarded as environmentally "dirty" technologies. The advent of contemporary biotechnology offers the potential to solve many of these problems by providing new routes for producing traditional products or by enabling the production of new material to fulfil commercial and practical objectives hitherto either unattainable, or attainable only by the production of environmentally unsatisfactory products. The key to these is the utilisation of biologically mediated catalysis either by employing purified enzymes or by using whole organisms. In this text, the potential of the biotechnological approach to chemical synthesis is desuibed and the strategy and outcome of applying biotechnological processes and principles to the syntheses of organic products are explained. Inevitably, authors have had to be selective, it is impossible to include all of the possibilities in a single text. A careful selection of examples have been made to cover both bulk, intermediate volume products and low volume fine products. The style is to use a more-or-less case study approach to illustrate the principles involved and authors have taken the opportunity to emphasise different aspects of their study areas. Thus, some give quite extensive examinations of the economics of processes whilst others focus mainly on the purely technical areas. The text therefore provides opportunities to learn about a whole range of issues in an array of product areas. The product specific chapters are built upon a generic section dealing with the advantages and limitations of using biotechnological approaches for satisfying chemical objectives. This text is targeted at a senior undergraduate/postgraduate level and should be of value to all engaged, or seek to be engaged, in the organic chemical industry in a wide variety of business sectors. It is built upon the assumption that readers have quite extensive biochemical and microbiological knowledge, although authors have incorporated many helpful reminders into relevant sections of their contributions. X Our thanks to the authors whose experience as researchers and as teachers is reflected in their quality of their contributions. Professor M C E van Dam-Mieras Dr C K Leach Scientific and Course Advisors: