The Biotechnology Annual Review series aims at covering developments in the field of biotechnology in the form of comprehensive, illustrated and well-referenced reviews. Recent expansion in this field, both industrial and educational, along with the increase in the number of new journals reporting new results, has greatly increased the need for exactly this type of series, continuously providing reviews.Every volume, published yearly, will cover a different aspect of biotechnology.The "Editorial Board" of Biotechnology Annual Review encourages suggestions and contributions of articles from industry or from academic institutions that would constitute a comprehensive covering of a relevant topic in biotechnology.Proposals for contributions and/or suggestions for topics for future volumes in this series should be sent to the Editor:Professor M.R. El-Gewely Department of biotechnology University of Troms? IMB, MH-Bygget N-9037 Troms? Norway Tel: (+47) 77 644654 Fax: (+47) 77 645350