Multiphase Bioreactor Design

CHAPTER FOURTEEN

BIOREACTOR DESIGN FOR PLANT

CELL SUSPENSION CULTURES

PATRICIA M.KIERAN

Department of Chemical Engineering, University College Dublin,

Belfield, Dublin 4, Ireland

ABSTRACT

Plants are the natural source of a vast array of phytochemicals which are

used as drugs, pesticides, flavourings and fragrances. In many cases, plant

cell suspension culture is a viable production alternative to traditional

cultivation methods or chemical synthesis. The use of suspension cultures

for biotransformations and for the production of heterologous proteins has

also been demonstrated. However, despite the obvious potential of these

systems, fewer than a dozen products have been produced at commercial

scale via the cell suspension route. Limited exploitation of the technology

is largely attributable to economic factors, associated with both biological

and engineering considerations. This chapter focuses on engineering

aspects of bioreactor design for plant cell suspension cultures. Adaptation

of bioreactor technology originally developed for microbial systems has

obviously proven successful for the commercial processes now in

existence. However, a fuller understanding of the distinguishing physical

and physiological characteristics of plant cell suspension cultures is

essential for the development of a broad-based and coherent strategy for

scale-up. System morphology, rheology and shear sensitivity are

identified as key factors for process design and optimisation. Existing and

emerging trends in cultivation practice are reviewed.

Keywords: plant cells, bioreactor, shear sensitivity, scale-up,

morphology, rheology

INTRODUCTION

Plant cell culture technology facilitates the production of valuable plant material and
phytochemicals under controlled and reproducible conditions; operation is independent of
the geographical and climatic constraints of conventional crop cultivation. Plant cell
cultures have traditionally been valued as a source of naturally occurring primary and
secondary metabolites, for use in medicinal, food and cosmetic products (Sahai, 1994).
They have been employed for biotransformations (Yokoyama, 1996) and it has been
established that they can be used for the production of heterologous proteins (Franken et