Identification of Cost-Relevant Factors in the Production of a Triterpenoid Saponin in Hydroponically Grown Soapwort: A Case Study

The economically efficient, reproducible cultivation of plants containing valuable ingredients for pharmaceutical or cosmetic purposes is a challenge today. Although greenhouse cultivation is much more expensive than field cultivation, this may be justified by the high level of control over environmental conditions. However, a careful analysis of costs and the investigation of potential cost-reducing measures are essential. Here, soapwort (Saponaria officinalis) was grown in a greenhouse to identify factors influencing the production costs of the pharmaceutically relevant saponin SO1861 in the roots. The plants were grown hydroponically to facilitate harvesting. Three factors were identified as having a significant impact on production costs: the genotype of the plants, the method of propagation, and the type of lighting used in the greenhouse. Commercially available soapwort seeds do not have a defined genetic background. Cost simulations suggest that the cost of producing SO1861 can be significantly reduced by pre-testing plants for SO1861 production capacity, propagating plants from cuttings rather than seeds, and using light-emitting diodes instead of the more traditional high-pressure sodium lamps. The impact of these factors on the total production costs was calculated and discussed. A simplified version of the cost model, which can be used as a blueprint for estimating the costs of any other greenhouse crop, was also included in the supporting data.