Carbohydrate Source, Biomass Productivity and Natural Product Yield in Cell Suspension Cultures

Abstract

A large number of carbon sources have now been tested for their ability to support the growth of plant cell cultures (Stepan-Sarkissian and Fowler 1984). The materials tested range from refined sources such as sucrose, glucose, and galactose to often complex carbohydrate containing waste materials such as milk whey and molasses (Table 1). They also cover a wide spectrum in regard to structure, properties, and molecular size. Of all the different carbon sources tested, however, none has been found to be as effective as sucrose or glucose in supporting both high growth rates and biomass yields. The use of these sugars also tends to result in high carbon conversion efficiency, often approaching and exceeding levels of 50%. In spite of this, it would appear that the two sugars, although structurally related, do not necessarily affect or influence the physiological status of all cell cultures in quite the same way. For instance in the case of Catharanthus roseus cell cultures maximum biomass yields were achieved in shorter periods of time with glucose than with sucrose (Fowler 1982). At the same time the efficiency of sucrose utilisation declined with increasing sugar concentration. In contrast, it has been shown that sycamore cells will utilise sucrose or glucose with equal facility (Simpkins et al. 1970). In this case the biomass yield and conversion efficiency rose [up to 6% (w/v) sucrose] as the level of sucrose supplied was increased.