Project Description

OVERVIEW

The fashion and cosmetics industries are highly consumer-centric, impacting nearly everyone worldwide. These industries consume vast quantities of raw materials and can significantly harm the environment. In the face of escalating plastic pollution and the pressing need for environmental conservation, our project, PETAL , presents a novel solution by seamlessly integrating plastic waste management with the preservation of Indigenous sandalwood trees through the power of synthetic biology. Here, we will employ engineered microorganism to uptake plastic (PET) monomers and then utilize them to produce sandalwood oil.

Plant terpenoids and applications

Isoprenoids, also known as terpenoids, are a class of organic compounds categorized based on their structure and pathways for their biosynthesis. All terpenoids are derived from dimethylallyl diphosphate (DAPP), and isopentyl diphosphate (IPP) can exist as mono- (C10), sesqui- (C15), di- (C20), sester- (C25), tri- (C30), tetra-(C40) to polyterpenes of greater than C40−C5×103−4 units [1]. Plant terpenoids have a wide range of applications in cosmetics and perfumery industries [2]. Terpenoids are the major components of plant essential oils that give them aromatic and therapeutic value. Many biotic and abiotic factors largely affect a plant's ability to produce essential oils (EOs), affecting the oil's yield and bioactive components [3].

Sandalwood oil, known for its high cost among plant essential oils, is reputed for its therapeutic and pharmacological benefits. These include antioxidant, anticancer, anti-inflammatory, antiviral, antibacterial, antifungal, hepatoprotective, and cardioprotective properties [4]. The price of Indian sandalwood oil is around Rs. 1,50,000 per kg as per the Government of India (GoI) rate [5]. It is especially prized in perfumery, offering a unique oriental, woody scent that also boosts and preserves the aromatic qualities of other fragrance ingredients.

Sandalwood depletion and its causes

Sandalwood plays a vital role in all aspects of human life within Indian culture and civilizations, ranging from the cradle to cremation, from the ancient Indus Valley civilization to the present day. Known as the 'king of woods', Indian sandalwood is a precious species with a long and sacred history. It has high demand in the cosmetic and perfumery industries worldwide. Santalum album (Indian sandalwood) is particularly preferred due to its higher concentrations of α-santalol and β-santalol than other species.

India reigns as the largest exporter of sandalwood in the world, with nearly 26,000 shipments. However, due to overexploitation and illegal harvesting of trees, we are slowly losing this precious treasure from our country. The International Union for Conservation of Nature (IUCN) recently declared sandalwood vulnerable. Since then, the Government of India (GoI) has imposed certain regulations on sandalwood farming and trade to eradicate the smuggling and corruption of wood.

Additionally, to meet the demand for products that use sandalwood oil, India began importing oil from Australia. Therefore, PETAL has taken the initiative to produce sandalwood oil through synthetic biology, helping to conserve native species of the tree while also meeting the demand for the oil.

Plastic pollution

Plastic pollution is a persistent issue worldwide. Despite being aware of its non-biodegradable nature and its environmental hazards, eliminating plastic is challenging. Its widespread use in industries and everyday life makes complete removal impractical. There is also a strong economic incentive, with plastics losing 95% of their material value after a single use, leading to an estimated annual loss of $110 billion to the global economy [6]. Without innovative approaches, the problem of plastic pollution will keep escalating. India recycles only 30% of its 3.4 million tonnes of annual plastic waste [7]. Innovative solutions are necessary to create a circular plastics economy. Hence, to work on this issue, we aim to engineer bacteria to utilize plastic monomers and further synthesize value-added products like plant essential oil.

Our Solution: PETAL

PETAL employs an innovative way to synthesize highly demanded sandalwood oil by upcycling waste plastic using engineered microbes.

Polyethylene terephthalate (PET), a commonly used plastic, comprises Terephthalic acid (TPA) and Ethylene glycol (EG) as monomers. We have imagined/designed a synthetic biology model where plant essential oils are produced by microbes feeding on PET monomers. This is ensured by engineered Pseudomonas putida, which can metabolize and grow solely on TPA and EG as carbon sources [8],[9] and can also synthesize terpenoids [10]. Natural sandalwood oil comprises sesquiterpenoids, majorly α-Santalol (45.8%) and β-Santalol (20.6%). We will be incorporating the Santalol synthesis pathway in P. putida for the first time, which has been previously demonstrated in E. coli and yeast [11],[12],[13]. This project can be a pioneering step towards microbial factories synthesizing plant secondary metabolites from plastic and can be extended to other essential oils with high therapeutic or fragrant properties.

Impact

PETAL holds significant potential for environmental benefits and positive impacts on society and the scientific community. Polyethylene terephthalate (PET), commonly used in plastic bottles, films, and other products, is a carbon chain that remains outside nature’s carbon cycle despite its abundance. Our solution degrades this waste plastic, releasing these carbons and transforming them into valuable products. This approach provides an advantage over other feedstocks due to its low cost and widespread availability, ultimately revolutionizing plastic recycling.

Our research focuses on synthesizing sandalwood oil from plastic monomers, providing sustainable solutions in synthetic biology by engineering bacteria to produce secondary metabolites and essential oils. This project demonstrates the potential of large-scale microbial use and supports a circular economy by upcycling waste into valuable resources, enhancing environmental sustainability.

Besides addressing plastic pollution and conserving sandalwood trees, we plan to expand into the cosmetics and perfumery industries. By refining our methodology through a design-of-experiments approach and utilizing large-batch culturing-based bioreactors, we aim to scale up production for cosmetic products such as perfumes, soaps, creams, incense sticks, and other therapeutic items.

References

  1. Tetali, S.D. Terpenes and isoprenoids: a wealth of compounds for global use. Planta 249, 1–8 (2019). https://doi.org/10.1007/s00425-018-3056-x
  2. Butnariu, M. (2021). Plants as Source of Essential Oils and Perfumery Applications. In Bioprospecting of Plant Biodiversity for Industrial Molecules (eds S.K. Upadhyay and S.P. Singh). https://doi.org/10.1007/s00425-018-3056-x
  3. Umra Aqeel, Tariq Aftab, M.M.A. Khan, M. Naeem, Regulation of essential oil in aromatic plants under changing environment, Journal of Applied Research on Medicinal and Aromatic Plants, Volume 32, 2023, 100441, ISSN 2214-7861, https://doi.org/10.1016/j.jarmap.2022.100441
  4. Shailja Choudhary & Gitika Chaudhary. (2021). SANDALWOOD (SANTALUM ALBUM): ANCIENT TREE WITH SIGNIFICANT MEDICINAL BENEFITS. International Journal of Ayurveda and Pharma Research, 9(4), 90-99. https://doi.org/10.47070/ijapr.v9i4.1895
  5. Sandalwood Information System, Institute of Wood Science and Technology (IWST)
  6. Sadler, Joanna C, and Stephen Wallace. “Microbial synthesis of vanillin from waste poly(ethylene terephthalate).” Green chemistry: an international journal and green chemistry resource: GC vol. 23,13 4665-4672. 10 Jun. 2021, doi:10.1039/d1gc00931a
  7. India recycles only 30 per cent of 3.4 MT plastic waste generated annually: Report (The Economic Times, 2023) https://economictimes.indiatimes.com/news/india/india-recycles-only-30-per-cent-of-3-4-mt-plastic-waste-generated-annually-report/articleshow
  8. Brandenberg et al. Microbial Cell Factories (2022) 21:119 https://doi.org/10.1186/s12934-022-01849-7
  9. Bao, T., Qian, Y., Xin, Y. et al. Engineering microbial division of labor for plastic upcycling. Nat Commun 14, 5712 (2023). https://doi.org/10.1038/s41467-023-40777-x
  10. Hernandez-Arranz, Sofía et al. “Engineering Pseudomonas putida for isoprenoid production by manipulating endogenous and shunt pathways supplying precursors.” Microbial cell factories vol. 18,1 152. 9 Sep. 2019, doi:10.1186/s12934-019-1204-z
  11. Yan Wang, Shenting Zhou, Qian Liu, Seong-Hee Jeong, Liyan Zhu, Xiangming Yu, Xiaojian Zheng, Gongyuan Wei, Seon-Won Kim, and Chonglong Wang Journal of Agricultural and Food Chemistry 2021 69 (44), 13135-13142 DOI: 10.1021/acs.jafc.1c05486
  12. Diaz-Chavez ML, Moniodis J, Madilao LL, Jancsik S, Keeling CI, et al. (2013) Biosynthesis of Sandalwood Oil: Santalum album CYP76F Cytochromes P450 Produce Santalols and Bergamotol. PLOS ONE 8(9): e75053. https://doi.org/10.1371/journal.pone.0075053
  13. Celedon, J.M., Chiang, A., Yuen, M.M.S., Diaz-Chavez, M.L., Madilao, L.L., Finnegan, P.M., Barbour, E.L. and Bohlmann, J. (2016), Heartwood-specific transcriptome and metabolite signatures of tropical sandalwood (Santalum album) reveal the final step of (Z)-santalol fragrance biosynthesis. Plant J, 86: 289-299. https://doi.org/10.1111/tpj.13162

Other References

  1. https://quintis.com.au/q-lab-knowledge-centre/sandalwood/indian-sandalwood
  2. https://www.volza.com/p/sandalwood/export/export-from-india/
  3. https://www.newindianexpress.com/states/karnataka/2023/Dec/17/felling-smuggling-of-sandalwood-trees-force-maker-of-mysore-sandal-soapto-import-oil-from-australia-2642338.html#:~:text=The%20company%20is%20importing%20the,of%20land%20to%20grow%20sandalwood.
  4. https://www.researchgate.net/publication/338434850_Sandalwood_in_India_Historical_and_cultural_significance_of_Santalum_album_L_as_a_basis_for_its_conservation
  5. https://faolex.fao.org/docs/pdf/ton158188.pdf
  6. https://www.urban-farmers.co/government-approvals-required-for-chandan.html