Reimagining the Circular Economy: How Plant Waste Could Transform Pharma and Cosmetics

[Un article de The Conversation écrit par Maher Abla – Enseignant-chercheur en chimie à l”ESTBB et membre du groupe de recherche “Biotechnologies, Santé, Ethique” de l’unité de recherche UR CONFLUENCE: Sciences et Humanités (EA 1598), UCLy (Lyon Catholic University) – Grégory Chatel – Enseignant-chercheur en chimie verte au laboratoire EDYTEM, Université Savoie Mont Blanc – Philip Lawrence – Professeur de l’UCLy en virologie, responsable du groupe de recherche “Biotechnologies, Santé, Éthique” de l’UR CONFLUENCE : Sciences et Humanités (EA 1598), UCLy (Lyon Catholic University) – Thanh-Nhat Pham – Enseignant-chercheur en chimie et biochimie à l’ESTBB et membre du Groupe de recherche ” Biotechnologies, Santé, Éthique ” de l’Unité de recherche CONFLUENCE : Sciences et Humanités (EA 1598), UCLy (Lyon Catholic University) ]

Beyond climate change alone and pollution, there are now several planetary limits that are about to be crossed. In this context, it is urgent to limit the use of raw materials derived from petrochemical products.

For this, a way is that of the circular economy. The latter, requested by the United Nations 2030 Agenda and supported by regulations such as the Circular Economy Action Plan (PAEC) of the European Commission and the anti-gaspillage law for a circular economy (AGEC), is more virtuous for the environment. They aim to limit the production of waste and the preservation of natural resources.

The valuation of plant waste from the exploitation of biomass represents a major opportunity for the circular economy. Often wrongly qualified as industrial waste, these by-products are still largely under-exploited, being mainly intended for composting, methanization or incineration. However, they conceal great potential for the food, cosmetics, even pharmaceutical industry, as sources of high -added molecules, whose production by conventional processes remains expensive and not very durable.

Biomass waste in the circular economy

The circular economy describes the process by which resources are extracted to make products, and where we will then recover and recycle the materials used at the end of the life of the product.

In this context, unused products – or become unusable – are transformed into new raw materials allowing their turn to create new products. The search for new renewable resources and eco -responsible revaluation processes is thus an important dimension of the cicular economy.

In this aspect, the valuation of biomass by-products, often wrongly qualified as industrial waste, is crucial.

The food and agricultural industries present an interesting potential in this regard. Biomass by-products can be classified into two main categories:

• Those generated in the fields (on the farm). Agricultural by-products, also known as harvesting residues, include stems, leaves and seeds of agricultural plants, as well as roots and envelopes derived from agricultural residues and processes of transformation of raw materials;
• and those generated by industrial transformation (outside the farm). Non-agricultural by-products, generated during industrial transformation, include peels, oils and marcs.

Each year, millions of tonnes of by-products from biomass, from the food industry, forestry and other industrial sectors, is considered to be waste. These by-products are generally eliminated by incineration, discharged, composted or used for energy production (methanization, for example).

These methods, even when they allow the valuation of waste, for example by producing fertilizers (composting) or energy (methanization), pose important environmental, social and economic problems.

The real issue is that, in this context, the by-products of biomass are not perceived as potential sources of rewardable biomolecules.

However, one can extract by-products from the biomass of the molecules with high added value. They can be useful in many industrial sectors, for example cosmetics, pharmaceuticals, food, biomaterials or water treatment. In addition, these molecules and biopolymers such as polyphenols, cellulose, hemicellulose and lignin are often difficult and/or expensive to produce Novo.

“Waste” rich in precious biomolecules

For example, tea waste is rich in bioactive molecules such as catechins, such as epigallocatechine gallate (EGCG) which has antioxidant, anti-pigmentation and protective effects against photodmages induced by UV. This makes them interesting for skin care products. Likewise, ginger marc is rich in antioxidants, making it a natural source of food preservatives.

Certain invasive plant species, such as the Renouted of Japan (Fallopia Japanica) or the Spanish broom (Spartium JUnceum) are also promising sources of bioactive molecules. For example, Japanese Renouée is rich in resveratrol, a polyphenol widely used in cosmetics for its antioxidant properties and its beneficial effects on the skin.

Biomass by-products can also constitute a nutritive substrate for microorganisms capable of producing biomolecules of interest.

Biosourced products can also replace numerous petroleum products, particularly in the production of bioplastics or biopolymers, thus contributing to the development of more ecological industries. The progress of biotechnologies and green chemistry will play a crucial role in this new approach to circular bioeconomy.

Another issue: that of treating and enhancing locally biomass waste to contribute to the resilience of the territories and to reduce transport -related emissions. The organization of the sector, as our research group recently pointed out during half a scientific day in the ways of better valuing biomass in the Auvergne-Rhône-Alpes region, is crucial.

The contribution of unconventional approaches

Conventional extraction techniques such as maceration, infusion, percolation or SOXHLET extraction require up to several days to produce interesting bioactive molecules from bio -waste. These methods often involve the use of extreme conditions, such as high temperatures and, in some cases, high pressure processes to accelerate extraction. Organic solvents are also frequently used, as target compounds are generally not very soluble in water.

These conventional processes have fairly low yields as well as other drawbacks. They generally consume a lot of energy, resulting in substantial greenhouse gas emissions and the use of toxic solvents derived from petrochemical sources.

In addition, the extreme conditions associated with these processes can alter the stability of the compounds, resulting in their degradation and a loss of bioactivity, especially for polyphenols, which limits the potential applications of the extracts obtained.

Inspired by the principles of green chemistry, eco-extraction offers alternatives to reduce these problems and contribute to the objective of sustainability. By that we mean, new approaches with a lower environmental impact, such as ultrasound, microwave irradiation, non-thermal plasma, mechanimal and other eco-innovations.

These methods require more environmentally friendly conditions and materials, including greener solvents. It may be alternative water or solvents to petroleum solvents, for example natural natural eutectics, English Natural Deep Eutectic Solvent (Nades). These are mixtures of natural compounds such as sugars, organic acids, amino acids, polyols or vitamins, which form a homogeneous liquid capable of replacing conventional organic solvents.

Supercritical fluids – such as supercritical co₂ can also be excellent substitutes for conventional solvents. The latter combine liquid and gas properties, thanks to an adjustment of pressure and temperature, to create an effective, non -toxic and more easily recyclable solvent for the extraction of natural molecules. The extraction assisted by microwave, finally, can even be performed without solvents.

Let's go back to our example of tea waste: the application of powerful ultrasound with crushed black tea waste increases the quantity of extracted polyphenols, which makes it more effective as an antioxidants compared to the extracts obtained using conventional techniques such as maceration.

Similar results have been obtained for the enhancement of apple marc, used coffee grounds and other industrial waste thanks to various innovative processes developed in the laboratory or semi-pilot scale.

Bioraffinery, a key model for the valuation of bio -waste

The approach of biofillerie is a promising model for the revaluation of agrifood bio -waste. This process aims to transform these residues into high value compounds thanks to a succession of targeted extraction stages. Each generated co -produced can thus serve as a raw material for the following steps, optimizing the use of resources.

To be effective, this model is based on technologies with low environmental impact and the use of green solvents such as water, natural natural eutectics (nades) or co₂ Supercritical. A rigorous organization of the sector, including local availability of raw materials and optimized management of waste flows, is also essential.

To reach a zero waste objective in these facilities remains a challenge. According to the applications targeted, the purification stages and the treatment of bioactive molecules after extraction are major issues. It is also crucial to develop reliable indicators to assess the environmental impact, to carry out life cycle analyzes from the laboratory scale and to anticipate economic and regulatory constraints slowing down industrialization.

The generalization of these green processes will depend on the ability to overcome these obstacles. By integrating these innovations into a circular economy model, plant waste can be transformed into precious resources, thus contributing to a more sustainable industry.