Conventional and New Approaches to Increase the Alkaloid Production of Plant Cell Cultures

Abstract

The commercial production of natural compounds from plant cell cultures has repeatedly been envisaged [1, 14,19, 23]. Recently the development of the first commercial process, the production of shikonin derivatives from suspension cultures of Lithospermum erythrorhizon, has been announced by Japanese scientists [7]. This first demonstration that plant cell cultures can indeed serve as a source of natural products must not conceal, however, the fact that we are still far away from a breakthrough in this area of biotechnology [2]. The conventional approaches (e.g. screening for highly productive variants, development of production media) were not really successful and thus not sufficient for many culture systems [2]. More knowledge on the molecular level about regulatory controls in the expression of secondary metabolism under cell culture conditions seems to be urgently needed. Our group has been involved in this area of biotechnology for 6 years. Here we would like to summarize briefly our experiences in increasing alkaloid formation of plant cell cultures by conventional methods. We also describe a new approach by which we hope to obtain a first insight into how to manipulate the expression of secondary pathways in plant cell cultures.