Harvesting with High Electric Field
A high electric field based harvestor for extracting taxoids from Taxus species was designed. The project was an interdisciplinary work involving botanist, electronics engineers, gardener, industrial designers and ecosophists.
Client: Botanical Garden, Delft, The Netherlands ; Master's Graduation Project at TU Delft; April - August 2010
Sustainable Harvesting: Taxoids are a group of anticancer drugs obtained from taxus species by cutting down the trees or from the needles (leaves) through chemical extraction. Thus the species is at the verge of extinction. Marijnissen & Roos (1999) devised a technique in which if a high voltage is applied perpendicular to a needle tip, the needle gave the pure chemicals eliminating the need for chemical extraction. If done properly this can be non-destructive and renewable source of the drug. The aim of the project was to convert this lab setup into a commercially viable system.
About the Project: The project was an interdisciplinary work involving botanist, electronics engineers, gardener, industrial designers and ecosophists. The major challenge of the project was to convert the single needle harvester to a branch harvester (around 3000 needles in natural arrangement) by bringing in coherence the expertise of the multidisciplinary team.
Usage: In this project, a single unit of the harvester was designed. The commercial setup needs to be a fully automated system consisting of more than 200,000 of these single entities.
Challenges: The major challenges tackled were very low yield (in picograms per needle), short-circuiting between needles and electrode which killed the needles and multitude of unknown factors like hedge shaping, species selection, environmental impact, relationship between harvesting and the voltage and current required.
USP of the concept: This harvester can be used across 8 different species of Taxus (which are very different structurally) and does not need any hedge trimming or shaping.
How Does it work?: A thorough study of branch and needle structures was done and the most suited geometrical shape, that can distribute the needles best, was conceptualized. Different geometrical modifications were done to this shape to achieve a uniform electric field in the harvesting zone. Selection of the insulator material was one of the most crucial steps in the process. A functional prototype was constructed and tested to prove the efficacy of all calculations and material properties.