Bioreactors for the cultivation of red beet hairy roots

Abstract

Since hairy root cultures of red beet were obtained at the end of the twentieth century, they have been intensively investigated over the past decade as producers of biologically active compounds, including food colorants (betacyanin and betaxanthin pigments), phenolic compounds, enzymes and other proteins and for understanding basic cellular physiologies as well as for engineering their container designs, such as bioreactors. The analyses of available data concerning their growth potential, nutrient needs and secondary metabolite pro fi les outline these types of in vitro cultures as effective producers of biologically active colorants for the food and pharmaceutical industries, although commercial scales are yet to be realized. The main limitation for the development of such technologies is the cost-effectiveness of the process and the need for re fi nement of an appropriate bioreactor system suitable for further scale-up. This chapter summarizes the recent advances in bioreactor cultivation of beet hairy root cultures. The application of bioreactor systems with different designs, optimization of the cultivation conditions, monitoring and assessment of the cultivation process, methods for enhancement of pigment production and strategies for on-line product recovery are reviewed, compared and discussed with the purpose of assessing their effectiveness for the development of an effective industrial process. The advantages of biotechnologically produced red beet colorants, their possible applications and the law frame for their regulation are discussed as well.