The main subject of the "Ill. Rotenburger Fermentation Symposium" is enzyme technology. Enzyme technology could be simply defined as the scientific study of proteinaceous catalysts derived from living organisms and the application of the knowledge to solve specific problems. The scope of the application of enzyme technology ranges from medical to industrial uses and in the future even living organisms as a source of enzymes may be replaced by fully synthetic enzymes - "synzymes". Although enzyme technology still remains a particular field of biotechnology, the extremely rapid rate of expansion and the enormous increase in the diversifica­ tion of all aspects of enzyme technology during the immediate past has created a certain tendency to separate biotechnology and enzyme technology from each other. Certainly, those areas of biotechnology characterized by astounding advances are enzyme technology, bioreactor development and genetic manipulation as related to biotechnological processes. However, a glance at many of the common problems of biotechnology and enzyme technology such as diffusion barriers, reactor design, mass transport, substrate or product inhibition pheno­ mena and the effect of physical-chemical parameters on process kinetics reveals that these two fields are inseparable with respect to research and application.