Sustainability
Consideration
In the investigation of Paclitaxel production, we considered how the current semi-synthetic pathway would be unable to meet increasing future demands sustainably. We sought to apply Synthetic Biology to address these main areas:
- Precursor's used in production are rare - 10-DAB is found at 0.1%, and Baccatin III at 0.0005% in the Yew Tree.
- Demand is supplemented through logging and debarking the yew tree
We also considered, beyond Synthetic Biology, the potential impacts of our pathway. We noticed a particularly pressing issue:
- An increase in demand for the Yew Tree's leaves. This will likely result in the exploitation of communities in the Himalaya, as well as over farming of the already endangered Himalayan Yew.
Engagement
To address the issues above, we researched into the potential to use more abundant pre-cursors to produce Paclitaxel. This guided our following Human Practices work - finding and working with Professor Ping Zhu's lab at the Peking Union Medical College. Professor Zhu research focus is around the possibility of producing Paclitaxel from Xylose De-acetyl Taxol, a more abundant analogue.
The next engagement in our investigation saw us work with environmentalists, botanists, Nepali Academics, and communities in the Himalaya. Here we aimed to proactively address the increasing demand for the Yew Trees leaves, through developing a sustainable farming guideline. This would help prevent exploitation of the endangered Himalayan Yew.
In the development of the guide, we first worked with environmentalists/botanists to develop farming techniques specific to the Himalayan Yew, that would ensure regeneration and genetic diversity within the species.
Then, through engagement with communities in the Himalaya, and Nepali Academics, we adapted the project to be more relevant to the area, and directly encourage the regeneration of the endangered Himalayan Yew.
Integration
Through our engagements seen above, we were able to achieve a few integrations summarised here. To learn more, click on iteration II of our IHP page.
- We applied Assemblase to improve upon the pathway to produce Paclitaxel from a more abundant pre-cursor Xylose Deacetyl Taxol. This moves increasing demand away from logging the Yew Tree, and towards the leaves.
- Working closely with Ping Zhu's lab to integrate their research into our pathway, and make it more efficient. We were taught how to better design and express an enzyme in the pathway called Xylosidase.
- Development of a Yew Tree farming guideline, that proactively addresses increasing demand for the Yew Trees leaves. By working with communities in the Himalaya and Nepali Academics, we could integrate their concerns and desires into the program, and hence better educate them on how to sustainable farm the Yew Tree.
Reducing our long term environmental impacts
Consideration
In our investigations and Education/Public Engagement work, we received social feedback about the potential harm adding another synthesis pathway would do to the environment. We considered how this would impact not just the environment, but also how it would concern society in general - especially with recent talks about climate change. In this investigation, we sought to consult with climate activists and green chemists to reduce our proposed pathways impact on the environment.
Through talking with green chemists, we received confirmation that our pathway was already a greener alternative to the current semi-synthesis. This was because it used only 2 reagents, none of which are toxic. This was a big improvement over the current semi-synthetic pathway, which uses 13 different solvents and reagents some of which are hazardous and toxic.
We continued to work with them to further reduce our impact, by incorporating concepts of green chemistry to our pathway. It aimed to improve upon these areas:
- Improve energy efficiency. The current semi-synthetic pathway uses a lot of energy.
- Reusing byproducts produced by our pathway.
- Making use of Biomass waste produced through extracting pre-cursors from the leaves
- Making use of Xylosidase, a byproduct in our pathway
Engagement
We engaged with Maddy, the social and climate activist who helped bring to our attention the need to reduce our pathways environmental impact. Following this, we collaborated with Dr. Douglass Macfarlane from the Australian centre of Green Chemistry, and the directors of the Green Chemistry Centre of Excellence (UK), Professor James Clark and Dr. Avtar Matharu. Through consistent back and forth engagement with these centres, we could continually push our project towards zero waste and impact on the environment.
Integration
Through engaging with the 2 Centres of Green Chemistry and the Climate Activist, we were able to make these integrations:
- Implementing the concept of atom economics, through recycling a byproduct produced from our proposed pathway into the current semi-synthetic pathway
- Identifying methods for Xylose extraction, and that it is a high value product.
- New lab practices that reduce our pathways energy consumption.