Team:Toulouse INSA-UPS/Description

The perfume industry

Smell is a cultural and social phenomenon: animals bond over odors and associate perceived smells with certain memories (Arshamian et al. 2013). It is therefore not surprising that fragrance molecules are nowadays used in a wide variety of products of our everyday lives. The global perfume market reached a value of US$ 32.8 Billion in 2020 and is expected to grow steadily during the next few years (Perfume Market). Fragrances are used in perfumes but also in many other cosmetic and hygiene products (Fernandez and Antoniotti 2016). France holds a position of historical player in the perfume and cosmetics industry. French cosmetics are in fact acclaimed throughout the world, where they are associated with expertise, quality, safety, glamour and luxury (Emmanuel Laheux 2016).

Figure 1: France, an historical actor of the perfume industry (pictures taken at the International Museum of Perfume, Grasse)

Mute flowers

Lilies, lilacs, honeysuckles, peonies, freesias, gardenias, violets, hyacinths: the smell of these flowers is imprinted in our memories, but it is impossible to extract their perfume from a natural source since they yield nothing or so little (Fernandez and Antoniotti 2016). These are called “mute flowers”.

"Flowers from which it is impossible to extract the fragrance"

Nowadays, perfumers and formulators of cosmetic products use mixtures of so-called “synthetic” molecules, i.e. produced by chemical means to mimic the smell of these flowers in their compositions. This type of ingredient is not sustainable: these molecules are petroleum-based, produced under harsh physico-chemical conditions through very energy consuming processes (for more information on the possible origins of perfume ingredients see our Implementation page) (Cataldo et al. 2016; Fernandez and Antoniotti 2016). These molecules also cannot be considered natural, which is a major challenge for perfumers and cosmetic companies, as consumer demand for naturalness is constantly increasing (Bom et al. 2019; Norm ISO 16128 2016; Norm ISO 9235 1997).

Figure 2: “L’orgue à parfum”, the perfumer’s organ is a professional piece of furniture designed to store most of the bottles of raw materials used by perfumers.

Toulouse, city of violets

Figure 3: Toulouse, city in the South West of France

One of these flowers, the violet, is the symbol of our city. The particular link between the violet and the pink city began, according to the claims, in 1850 when a soldier of Napoleon III brought back a Parma violet to his beloved living in Toulouse. From that time onwards, the Toulousans started to grow this flower which now lends its image to local products ranging from cosmetics to confectionery (Chervin 2018). Violet scents, which are often described as sweet, powdery and woody floral notes, are furthermore highly desired in the cosmetics and perfume industry.

What molecules are responsible for the scent of violets?

The characteristic odorants of violet scent have been discovered progressively as analytical techniques have evolved. Analytical studies are available in the literature with particular interest in headspace chromatography methods which are valuable tools for the detection of volatile substances in a liquid or solid sample (Saint-Lary 2015; Chervin 2018).

Figure 4: The violet, symbol of Toulouse

The most prominent substances of the violet scent are ionones: α-ionone, β-ionone and, to a lesser extent, dihydro-β-ionone (Saint-Lary 2015; Chervin 2018). These molecules belong to the family of terpenes and more specifically are called C13-apocarotenoids. Their fragrance activities are exceptional as their odor threshold is below the parts-per-billion range (Larsen and Poll 1990). Analysis of violets in bloom showed that ionones make together about 75% of the global headspace (Gautschi et al. 2001). Another terpene, linalool which is present in the fragrance of many flowers has also been identified in the olfactive profile of the violet (Saint-Lary 2015; Chervin 2018). Finally, the C9-aldehyde family of molecules completes this olfactory landscape with greener notes. The dominant constituents of this family in violets are (2E,6Z)-nonadienal and (2E,6Z)-nonadienol which are commonly referred to as “violet leaf aldehydes” (Saint-Lary 2015; Chervin 2018).

ELIXIO:
a synthetic microbial consortium for sustainable violet fragrances

Biotechnological approaches such as bio-catalysis and metabolic engineering of microorganisms raise interesting opportunities for bio-production alternatives, especially in the fragrance industry. These processes are bio-sourced, occur in mild physicochemical conditions and with usually higher selectivity than chemical synthesis. Finally, fragrances obtained through biotechnological processes can be considered natural according to US and EU regulations, which is an extremely important factor in today's perfume and cosmetics market (Cataldo et al. 2016; Norm ISO 16128 2016; Norm ISO 9235 1997).

We are iGEM Toulouse and we are convinced synthetic biology has a lot to bring to the perfume world. To demonstrate this potential, we decided to give its voice back to our local flower, the violet, as a proof of concept of our approach.

Traditional industrial biotechnology approaches usually focus on the production of a single molecule. Here, we have designed a modular platform to reconstitute the olfactory profile of the violet in a biomimetic perspective. We therefore chose to focus on the molecules previously identified: on one hand, terpenes (α-ionone, β-ionone, dihydro-β-ionone and linalool) and on the other hand, violet leaf aldehydes ((2E,6Z)-nonadienal and (2E,6Z)-nonadienol). These two families of molecules are produced in different metabolic pathways. We therefore imagined a synthetic microbial consortium between two different chassis by taking advantage of their metabolic and physiological specificities. The production of the violet terpenes is ensured by the yeast Saccharomyces cerevisiae, while the violet leaf aldehydes are produced by the fast-growing cyanobacterium Synechococcus elongatus UTEX 2973. Our cyanobacterial strain has also been engineered to secrete sucrose, which is used as a carbon source by the yeast, making co-culture possible. The combination of these two microorganisms, one autotrophic and one heterotrophic, makes it possible to obtain truly sustainable fragrances as they are derived from CO₂.

Figure 5: ELIXIO, a synthetic microbial consortium for sustainable violet fragrances. Sucrose secreting Syn UTEX 2973 provides a carbon source for the yeast. The production of molecules of interest is shared between the two organisms by taking advantage of their physiological specificities.

Since the olfactory properties from a mix of molecules are very dependent on their proportions, we decided to include induction systems to control the expression of the key enzymes of our pathways. Our idea is to allow “tailor-made” mixes of fragrances that could then, after extraction, be characterized by expert perfume formulators (also known as “noses” in the industry). This empirical approach would enable us to get as close as possible of a convincing violet smell. By combining synthetic biology with the art of perfume creation, we hope to provide a sustainable equivalent of violet essential oil to enrich the formulators' palette.

References

Arshamian A, Iannilli E, Gerber JC, Willander J, Persson J, Seo H-S, Hummel T, Larsson M. 2013. The functional neuroanatomy of odor evoked autobiographical memories cued by odors and words. Neuropsychologia. 51(1):123–131. doi:10.1016/j.neuropsychologia.2012.10.023.

Bom S, Jorge J, Ribeiro H, Marto J. 2019. A Step Forward on Sustainability in the Cosmetics Industry: a review. Journal of Cleaner Production. 225. doi:10.1016/j.jclepro.2019.03.255.

Cataldo VF, López J, Cárcamo M, Agosin E. 2016. Chemical vs. biotechnological synthesis of C13-apocarotenoids: current methods, applications and perspectives. Appl Microbiol Biotechnol. 100(13):5703–5718. doi:10.1007/s00253-016-7583-8.

Chervin J. 2018. Etude de la spéciation chimique de la collection nationale de violettes et mise en place d’un agro-raffinage de la violette de Toulouse. :299.

Emmanuel Laheux. 2016. Globalisation du marché cosmétique : Géoanalyse des principales marques nationales dans le monde. :149.

Fernandez X. et Antoniotti S. 2016 Jan 10. Parfums : matières premières, formulations et applications. Ref : TIP453WEB - “Formulation.” [accessed 2021 Feb 17]. https://www-techniques-ingenieur-fr.gorgone.univ-toulouse.fr/base-documentaire/42689210-cosmetiques-produits/download/j2304/parfums-matieres-premieres-formulations-et-applications.html.

International standard ISO 9235 - Aromatic raw materials. 1997. https://www.iso.org/obp/ui/#iso:std:iso:9235:ed-2:v1:en.

International standard ISO 16128- Lignes directrices relatives aux définitions techniques et aux critères applicables aux ingrédients et produits cosmétiques naturels et biologiques. 2016. https://www.iso.org/fr/standard/65197.html.

Gautschi M, Bajgrowicz JA, Kraft P. 2001. Fragrance Chemistry — Milestones and Perspectives. CHIMIA International Journal for Chemistry. 55(5):379–387.

Larsen M, Poll L. 1990. Odour thresholds of some important aroma compounds in raspberries. Z Lebensm Unters Forch. 191(2):129–131. doi:10.1007/BF01202638.

Perfume Market: Industry Trends, Size, Share, Analysis & Forecast 2021-2026. [accessed 2021 Jul 6]. https://www.imarcgroup.com/perfume-manufacturing-plant.

Saint-Lary L. 2015. Évaluation de l’approche métabolomique pour l’authentification des extraits naturels utilisés dans le secteur arômes et parfums [phdthesis]. Université Nice Sophia Antipolis. [accessed 2021 Mar 17]. https://tel.archives-ouvertes.fr/tel-01189109.