Plants are important sources of many secondary metabolites including drugs, enzymes, fragrances, flavors, and pigments. The objective of this study was to investigate the potential for the production of strawberry flavor and pigment from a strawberry cell culture system. Immature strawberry fruits from strawberry cultivars (Fragaria x ananassa cv. Brighton, Earliglow, and Aptos) were cultured on modified Murashige and Skoog medium supplemented with 2,4-dichlorophenoxy acetic acid. Parameters that influenced callus formation including medium composition, concentration of phytohormone, and photoperiod were investigated. Medium composition, inoculum size, and type and concentration of phytohormones were found to have different degrees of influence on the growth rate of 'Brighton' cell suspension cultures.
Production of secondary metabolites from strawberry cell cultures were studied. Light illumination showed a strong effect on red pigment formation in strawberry callus cultures. Several organic acids were used as precursors to stimulate flavor synthesis from strawberry cell suspension cultures. Flavor components were analyzed by headspace gas chromatography with splitless injection and liquid nitrogen cold trapped techniques. Analysis of the headspace by gas chromatography revealed that when supplemented with butyrate and $alpha$-keto-valerate, strawberry cell suspension cultures were capable of producing low concentrations of ethyl butyrate, butanal, and butanol which are important components of strawberry flavors. No aroma compounds were produced in unsupplemented cell suspension cultures. The results indicated that esterase, decarboxylase, and alcohol dehydrogenase might exist in strawberry cell suspension cultures.
To investigate the potential of mass production of strawberry cultures, growth kinetics of cell suspension cultures in shake flasks, airlift bioreactors, stirred-jar and roller bottle bioreactors were studied. The specific growth rates of strawberry cell suspension cultures were higher in the baffled roller bottle system (0.15 day$sp{-1}$) than any other systems studied. We were not able to grow cell suspension cultures in the stirred-jar bioreactors. The baffled roller bottle showed the best potential for scale-up for mass production of cell.