LEDitSHAKE – A Lighting System to Optimize the Secondary Metabolite Content of Plant Cell Suspension Cultures

Abstract

1.1 Background Plant secondary metabolites are widely used in the food, cosmetic and pharmaceutical industries. They can be extracted from naturally grown plants or plant cell suspension cultures grown under sterile conditions. In the latter case, yields and quality strongly depend on the cultivation environment, including optimal illumination. Current shaking incubators do not allow different light wavelengths, intensities and photoperiods to be tested in parallel. We therefore developed a system for multiplexed customized illumination within a single shaking incubator, and used it to optimize anthocyanin production in grapevine cell suspension cultures. 1.2 Results We used 3D printing to integrate light-emitting diode assemblies into flask housings to develop the LEDitSHAKE system, allowing 12 different lighting conditions (spectrum, intensity and photoperiod) to be tested simultaneously in a single shaking incubator. We used a Design of Experiments approach to determine the effect of 24 different light compositions on the total anthocyanin content of replicate grapevine cell suspension cultures. All tested conditions achieved higher yields than standard illumination or dark cultivation, and the optimal spectrum (8.3 µmol m− 2 s− 1 red, 8.3 µmol m− 2 s− 1 green, 33.3 µmol m− 2 s− 1 blue, and UV turned on) increased the total anthocyanin concentration by 2.42-fold after 4 weeks. Based on the resulting model, we predicted the optimal lighting conditions for the upregulation and downregulation of 30 anthocyanins, and found that short-wavelength light (blue, UV) maximized the concentration of most anthocyanins, whereas long-wavelength light (red) had the opposite effect. For example, the cyanidin glucoside concentration was predicted to increase 2.99-fold compared to the source culture with optimized illumination (12 µmol m− 2 s− 1 green, 38 µmol m− 2 s− 1 blue, and UV turned on for 1 h/day). 1.3 Conclusions The LEDitSHAKE system enables the screening of up to 12 different lighting conditions in terms of spectrum, intensity and photoperiod within a single shaking incubator using a Design of Experiments approach, as exemplified by the optimization of the anthocyanin content and composition in grapevine cell suspension cultures. Our results demonstrate proof of principle that the LEDitSHAKE system is suitable for the optimization of processes based on plant cell suspension cultures.