Introduction

The fragrance industry has expanded beyond perfumes and air fresheners, with scent marketing playing a significant role in the retail and hospitality sectors. The market is expected to reach US$ 6.0 billion by 2032[1]. Essential oils (EOs) are greatly valued in this industry for their aromatic properties. These oils capture the essence of a plant’s fragrance and are frequently used in the cosmetics and hospitality industry. However, we noticed the unfortunate floral waste from fresh flowers that needs to be changed and replaced as they do not smell good or look presentable after one to two weeks. Moreover, conventional extraction methods like hydro-distillation and steam extraction have limitations such as loss of volatile compounds and inclusion of undesired products. Due to low production efficiency, huge swathes of farmland are needed to grow sufficient amounts of floral feedstock just for EO production. To address these issues, our proposed approach focuses on enzymatic facilitation of extraction of essential oils.


Essential oil utilisation

In Macao, a city heavily supported by the hospitality industry, a hotel may host intricate floral displays and landscaping comprising as many as 1.5 million plants[2] and seasonal flowers. However, the large-scale implementation of floriculture scent marketing in hotels is generating flower waste at an increasing rate. Rather than throwing away these wastes, we believe they can be further repurposed into essential oil which can then be used in the hotel again for scent or self-branded cosmetic products.


Besides its usage in the hospitality industry, EOs have been used throughout history for therapeutic, aromatic, recreational, flavouring and many other purposes. We believe that the improvement of EO production can greatly benefit multiple industries across the globe.


Limitations of traditional essential oil production

Most essential oils currently on the market are extracted by one of the following two methods: Hydro-distillation and steam extraction. Other developed extraction techniques include enfleurage of roses, cold pressing for citrus peel, and solvent extraction. These techniques have several downsides, including limited yield, loss of volatile compounds, long extraction times, and dangerous solvent residues. The total annual byproduct of the traded amounts of essential oils should have been approximately 52 million tons of vegetal material[3], most of which end up in landfills.


Our proposal

Improve yield efficiency

To offset the ever-growing wastage from industries, we propose an alternative method of essential oil production. Our project utilises engineered bacteria that produce cellulase cex and cenA (previous BBa_K118022 and BBa_K118023, now BBa_K5193002), pectinase pelA_therm ( BBa_K5193000) and pelA ( BBa_K5193001), and beta-glucosidase (previous BBa_K2929003) capable of breaking down plant cell walls, thus releasing essential oils. The enzymes are also thermostable[5][6][9][4], allowing further degradation under the high temperature of the steam distillation environment. This can be very useful in practice because most of the current EO extractions are done by steam extraction (93%)[7]. The ultra-specific nature of enzymes allows the essential oils to be liberated from the plant cells without damage to their native structure, and controlling the bioreactor at the optimum pH and temperature for enzymatic activity can maximise the degradation of the cell wall, achieving the primary aims of essential oil extraction.


Prolonging scent longevity

Another challenge in essential oil extraction is the inherent toxicity of certain chemicals, particularly terpenes, which limits their applications in various industries. To overcome this issue, we introduce candida rugosa lipase (lip4) to esterify the primary extraction product, thereby removing toxicity and enhancing the terpenes' volatility and olfactory characteristics[8].

Figure 1. Mechanism of our enzymatic EO facilitation system.

Aim and target

Our primary objectives revolve around two key aspects: flower upcycling and enhancing the quality of essential oil. Firstly, we aim to efficiently extract essential oils from flower waste, maximising resource utilisation and mitigating environmental impact due to discarded flowers. Secondly, we strive to enhance the quality of the extracted oils by prolonging their scent duration through the application of biotechnology, such as enzyme incorporation and esterification processes.


Our vision is to foster a more sustainable and responsible fragrance industry. By embracing cutting-edge technologies and promoting upcycling within local industries, we aspire to nurture a responsible consumption culture. We seek to reshape waste management strategies, focusing on reducing waste at the source and promoting the efficient recycling of resources.


Advantages

Our proposal improves essential oil extraction by using enzymes to efficiently break down plant cell walls, increasing yield and preserving the quality of the oils. This method is more environmentally friendly, as it repurposes floral waste and reduces the need for extensive land use. Additionally, the use of thermostable enzymes allows for seamless integration with steam distillation, the industry standard. By esterifying the extracted oils, we enhance their scent longevity, making them more suitable for various applications. Overall, our approach offers a sustainable and efficient solution for the fragrance industry.


References

  1. https://www.businessresearchinsights.com/market-reports/scent-marketing-market-112686
  2. https://macaudailytimes.com.mo/geg-supports-to-build-a-sustainable-future.html February 6, 2023
  3. Elena S. and Jairo RM. Essential Oils and the Circular Bioeconomy. 06 November 2023. DOI: 10.5772/intechopen.112958
  4. Ramani G, Meera B, Vanitha C, Rajendhran J, Gunasekaran P. Molecular cloning and expression of thermostable glucose-tolerant β-glucosidase of Penicillium funiculosum NCL1 in Pichia pastoris and its characterization. J Ind Microbiol Biotechnol. 2015 Apr;42(4):553-65. doi: 10.1007/s10295-014-1549-6. Epub 2015 Jan 28. PMID: 25626525.
  5. Saxena H, Hsu B, de Asis M, Zierke M, Sim L, Withers SG, Wakarchuk W. Characterization of a thermostable endoglucanase from Cellulomonas fimi ATCC484. Biochem Cell Biol. 2018 Feb;96(1):68-76. doi: 10.1139/bcb-2017-0150. Epub 2017 Oct 5. PMID: 28982013. https://pubmed.ncbi.nlm.nih.gov/28982013/
  6. Chen, Y.-P., Hwang, I.-E., Lin, C.-J., Wang, H.-J., & Tseng, C.-P. (2012). Enhancing the stability of xylanase from Cellulomonas fimi by cell-surface display on Escherichia coli. Journal of Applied Microbiology, 112(3), 455–463. doi:10.1111/j.1365-2672.2012.05232.x
  7. Zoubeida S. Essential Oil Extraction Process. 06 December 2023. DOI: 10.5772/intechopen.113311
  8. Tang SJ, Sun KH, Sun GH, Chang TY, Lee GC. Recombinant expression of the Candida rugosa lip4 lipase in Escherichia coli. Protein Expr Purif. 2000 Nov;20(2):308-13. doi: 10.1006/prep.2000.1304. PMID: 11049754.
  9. Berensmeier, S., Singh, S.A., Meens, J. et al. Cloning of the pelA gene from Bacillus licheniformis 14A and biochemical characterization of recombinant, thermostable, high-alkaline pectate lyase. Appl Microbiol Biotechnol 64, 560–567 (2004). https://doi.org/10.1007/s00253-003-1446-9