The resin found in agarwood (described as liquid gold) is used to produce agarwood oil (Stock Photo)
The chemical complexity of the aromatic sesquiterpenoids found in the agarwood tree prevents them from being produced industrially, which has put pressure on these trees, which are threatened with extinction and are the main source of these compounds.
Obtaining these compounds, in the absence of an industrial form of production, depends on the gummy resin found in the wood of the “oud tree.” The resin is distilled to prepare “oud oil,” which represents a major component of high-end and expensive perfumes. The price of one kilogram of this is estimated. The resin costs about 300,000 Hong Kong dollars, making it more expensive than gold.
In order to find an environmentally friendly method that reduces dependence on this resin, and thus reduces the removal of trees, researchers from the Manufacturing Sustainability Team at King Abdullah University of Science and Technology in Saudi Arabia (KAUST) announced in a study published by the Green Chemistry journal, their success in finding a method. Aleppo allows a type of algae to extract aromatic sesquiterpenoids from it, after using genetic engineering techniques to push the algae to produce these compounds, which represents an innovative alternative to the perfume industry.
The resinous substance that is distilled to produce oud perfume, the price of a kilogram exceeds the price of gold (Bing.com)
Solving the mystery of sesquiterpenoids
The researchers started off by trying to decipher the chemical complexity of the sesquiterpenoids. In this context, they analyzed 58 samples of agarwood using advanced techniques, as follows:
2D chromatography or 2D chromatography
; The sample is passed over two chromatographic columns (a chromatographic column is a cylindrical column filled or coated with a substance through which the sample passes), and this two-dimensional separation allows for better analysis of compounds, and is used as a more advanced alternative to traditional chromatography when the compounds are complex, as is the case in sesquiterpenoids. ".
mass spectrometry
; This tool, combined with two-dimensional chromatography, provides additional information about the molecular structure of the separated compounds. As each compound leaves the cylindrical column for chromatography, it enters the mass spectrometer, where it is ionized and fragmented. The resulting mass spectra provide unique “fingerprints” that help identify the compound. High accuracy, allowing accurate determination of molecular weights of compounds.
From this stage, the researchers concluded by identifying nine basic structures for aromatic sesquiterpenoids, which are the basic compounds responsible for the smell, which are “agarofuran”, “agarospiran/phytispyran”, “cadinene”, “eremophilan/valensine”, “eudesman/selenin”, and "Guayanese", "Presizanes", "Guaini" and "Zayzane".
Image of product made using a new biomanufacturing process developed by KAUST (KAUST)
Metabolic engineering of algae
The unprecedented identification of essential aromatic structures in sesquiterpenoids led the research team to employ metabolic engineering techniques to genetically modify the single-celled alga Chlamydomonas reinhardtii, making them function as biological factories capable of producing these structures.
The researchers introduced using "gene editing" technology; Genes encoding enzymes responsible for the biosynthesis of aromatic compounds in the algae genome. Through the expression of these genes, the alga Chlamydomonas reinhardtii was able to produce the required aromatic structures.
These algae were chosen as a natural factory for producing aromatic structures for several reasons mentioned by the researchers in their study, which are:
First,
the single-celled alga Chlamydomonas reinhardtii is susceptible to genetic manipulation, making it an ideal candidate for metabolic engineering experiments.
Second:
its ability to photosynthesize, which means it can harness light energy to convert carbon dioxide into organic compounds, and this ability to photosynthesize provides a sustainable and renewable source of carbon for the biosynthesis of aromatic compounds.
Third:
Algae are generally considered safe organisms for laboratory research, and Chlamydomonas reinhardtii specifically are non-pathogenic and non-toxic, and their use in metabolic engineering reduces ethical concerns and safety risks associated with working with genetically modified organisms.
Agarwood, from which the precious resin is extracted (Getty)
Microbial milking technology
After genetic engineering techniques succeeded in causing the algae Chlamydomonas reinhardtii to produce aromatic structures, the stage of extracting these structures from the algae comes through an innovative, low-energy algae milking technology developed by the research team.
Like collecting honey from beehives without harming the bees, the developed technology recovers the target compounds while keeping the algae cells intact. This is achieved through methods that allow the compounds to diffuse outside the cells without causing them to rupture.
The researchers then used “solvent nanofiltration” technology to concentrate and purify the aromatic structures produced by the genetically engineered algae. This technology allowed them to retain those desired structures and selectively concentrate them while removing impurities and unwanted solvents, thus facilitating the final processing. This is an energy-saving process. Much like separating gold from sand, it concentrates the extracted aromatic structures, making them more accessible for further processing.
The chemical structures extracted from the algae underwent a processing phase - which is similar to cooking with organic ingredients in a sustainable kitchen - during which the researchers used the principles of green chemistry to modify and enhance those structures, resulting in the generation of 103 types of aromatic sesquiterpenes similar to those found in agarwood.
Abundant production and other advantages
“Their method for engineering the alga Chlamydomonas reinhardtii provided a high production of aromatic sesquiterpenoids that was up to 25 times greater than what has been reported in efforts to achieve high yields of aromatic sesquiterpenoids,” said KAUST Manufacturing Sustainability Team Leader and lead researcher on this study, Assistant Professor Kyle Laursen, in a statement issued by KAUST. Previous research.
He explains that this large production is essential for commercial viability, and ensures that sufficient quantities of aromatic compounds can be produced to meet industrial requirements. In addition to the important advantage of abundance, there are several important environmental and industrial advantages that Laursen points out, including:
Sustainable perfume production
; By harnessing metabolic engineering and green bioprocessing techniques, researchers have developed a sustainable alternative for perfume production that reduces reliance on environmentally harmful methods such as clearing trees to obtain agarwood.
Diversified composite production
; The researchers were able to produce a variety of 103 aromatic sesquiterpenoids. This represents a significant expansion of the chemical space available for perfume production, providing a wide range of compounds for perfumery applications.
Operation at room temperature
; The entire biological process - including metabolic engineering of algae and green chemical transformations - can take place at room temperature, eliminating the need for energy-intensive heating or cooling processes, reducing energy consumption and operating costs.
Minimal waste generation;
The green bio-process developed by the researchers produces minimal waste, making it an environmentally friendly and sustainable alternative to producing fragrance compounds.
Accessible technology
; The simplicity of the bioprocess allows for easy implementation in laboratories equipped with basic chemical infrastructure, and this accessibility enables researchers in diverse environments to participate in sustainable fragrance formulation.
Industrial production challenges
The amazing success at the laboratory level is considered a positive indication of the possibility of achieving success at the industrial and applied level of the method of producing perfumes through biosynthesis in algae, says Amr Abdel Mohsen, professor of chemistry at Ilmenia University (southern Egypt).
But in order for these signals to turn into a practical reality, Abdel Mohsen stresses the need for researchers to clarify many points related to industrial production in subsequent studies. He says that among the most important things that researchers must clarify in these subsequent studies are the following:
Comparison of aroma compounds produced
using the developed bioprocess; The traditionally extracted compounds are examined in terms of fragrance form, intensity, longevity, and consumer preference. A complete file must be prepared on the sensory properties and olfactory profiles of these compounds.
Explain the challenges and considerations related to industrial-scale production
, how they can be addressed to facilitate the commercialization of the technology, and whether there are ways to further improve algal metabolic engineering and green chemical transformations to enhance productivity, selectivity and efficiency.
Explaining the economic implications of adopting the developed bioprocess for producing perfume compounds
, how the cost of production can be compared to traditional methods, and what are the factors that affect the overall cost effectiveness and feasibility of the technology in the market.
Source: Al Jazeera + websites