Clostridia: Biotechnology and Medical Applications

In the public eye, bacteria of the genus Clostridium are often misconceived as being a biological threat and thus a foe to mankind. However, only a few of the more than 150 validly described clostridial species produce potent natural toxins, such as botulinum or tetanus. Furthermore, even these have since become valuable tools in the treatment of severe diseases.

Clostridia belong to the avant-garde of biotechnologically important microbes. In the past, they were used for the production of industrial solvents, indigo dyeing, and flax retting. Nowadays, they exhibit enormous potential as producers of industrially important enzymes and in biotechnological processes such as the cleaning up of dumping sites or raw oil recovery. Therapeutic applications are, for example, the treatment of muscle spasms and cancer therapy.

This book will correct the misconception of generally bad clostridia by providing a comprehensive and up-to-date overview, while also detailing applications of these bacteria, whether already in use or soon to be introduced in the fields of biotechnology and medicine.

PREFACE

What a bad smell! a typical reaction when students in our laboratories open a tube in which Clostridium strain is growing. The odor of butyric acid is not the only bad reputation clostridia have. In the general public, clostridia are synonymous with pathogens, since everybody has to vaccinated against tetanus, and food is jeopardized to be poisoned by clostridia through one of the most potent natural toxins, botulinum. In science, many researchers do not like working with obligatory anaerobic bacteria (special techniques for cultivation have to be applied) and they prefer investigating easy to handle model organisms such as Escherichia coli or Bacillus subtilis.

In this book the other (good) side of clostridia is highlighted. After a historical perspective and a general overview, the diversity of clostridia is presented to the reader in two chapters. In the following chapter, the industrial acetone-butanol fermentation by Clostridium acetobutylicum is described, as performed in South Africa up to the 1970s. Since the possible re-introduction of the applied acetone-butanol fermentation will depend on the ability to engineer the metabolism of C. acetobutylicum, genetic tools developed in the last decade for these clostridia are reviewed in another chapter. Molecular analysis of clostridia in general is a prerequisite for the application of their different potentials. The last part of the book deals with clostridial toxins, neurotoxins and their medical applications. Furthermore, the use of recombinant clostridia in cancer therapy as outlined in the final chapter is another exciting example showing how bacteria, misconceived as being a biological threat to humans, can be very beneficial.

We are indebted to each of the contributors for making this book possible. Finally, we hope that this book will contribute to a wider appreciation of the useful capabilities which are present in members of the genus Clostridium.

Rostock and Ulm,

Hubert Bahl

Peter Durre

February 2001