Bark as underutilized material. Prospects of its application in active packaging.

Bark’s inherent strength and solid temperature tolerance make it suitable for a variety of applications, especially in renewable rigid packaging, creating a new high-potential niche. Image courtesy of Bpacks

By Nikolay Semenov, Chief Scientific Officer & Co-Founder of Bpacks and Aleksandra Nešić, Head of Innovations at Bpacks

Nature is the best creator. So why do people always strive towards artificial solutions when nature has it all? The wood industry is witnessing steady annual growth, since the demand for wood-based products has increased in recent years. This is driven by both emerging laws and directives towards zero waste products and heightened consumer awareness of the environmental impact of non-sustainable products.

One of the by-products of the wood industry is tree bark, which is, at the same time, a highly valuable and underutilized raw material. In the life of a tree, the bark plays a very important role. Bark accounts for approximately 5-10% of the total weight of a tree and serves a protective function against environmental conditions such as extreme temperatures, as well as against microbial contamination. Beyond its mechanical protective role, bark (depending on the tree variety) contains very potent anti-inflammatory, antioxidant, and antimicrobial components.

In general, bark consists of biopolymers, lignin, tannins, suberin and polysaccharides (such as cellulose and hemicellulose). The ratio of these components varies depending on the tree species. Lignin, constituting almost 40% of the bark, plays a key role in maintaining the tree’s structure and shape.  Tannins, the second major component, give the bark a color and protect it against various agents due to their antioxidant properties. Tannins, being polyphenolic compounds, exhibit significant activity and hold great potential applications. Suberin acts as a natural shield against microbial contamination of trees. This lipophilic biopolymer serves as a biochemical precursor for synthesizing a variety of antimicrobial compounds. Additionally, cellulose and other fibrous materials are present in the bark, but in smaller quantities compared to other parts of the tree. These levels impact the bark’s fibrosity.

Throughout history,bark has been utilized in folk medicine as a pain relief agent, wound care material, and chewed to treat some medical conditions. All of this was done without really understanding where the positive effect came from. Maybe the most known variation of bark is Salix alba or Willow, which, for centuries,  was used for treating pain, fever and inflammation due to its salicin content, a component similar to aspirin. Furthermore, wild cherry bark is used for cough, while white oak bark is used for ailments such as arthritis, diarrhea, colds, fever, cough, and bronchitis, as well as for stimulating appetite and improving digestion. Black and white birch bark contain betulin and betulinic acid in smaller amounts, which have strong antiviral properties that can combat viruses like influenza and HIV. It can also have anti-allergic, anti-inflammatory, hepatoprotective, and antituberculosis effects.

Today, around 300-400 million m3 of bark are produced annually, and a huge part of it ends up as waste. While a small amount of bark is used for decorative purposes and in the civil engineering sector, primarily as insulation material, the majority of wasted bark finds its way to various disposal methods. Some of this waste is repurposed for chemical production, mainly for extracting active components usable in cosmetics, medicine, and other industries. However, due to its origin as a byproduct of the wood industry, bark is sometimes incinerated as a bio-source of energy. Yet, compared to other tree parts it serves as a relatively low-caloric energy source. Unfortunately, in most of these cases, bark refining involves the utilization of chemicals, which can be harmful to the environment.

The protective qualities of bark, capable of withstanding a wide range of environmental conditions, prompt the question: why couldn’t it protect something else? We propose harnessing bark as a packaging material, not only for food but also for other products such as electronics, leveraging its exceptional properties. Unlike other biopolymer materials, bark can be equally degradable, biodegradable and compostable, whether at home or industrial composting facilities.  When discarded in nature, it enriches the soil with valuable nutrients, fostering plant growth. Its inherent strength and solid temperature tolerance make it suitable for a variety of applications, especially in renewable rigid packaging, creating a new high-potential niche.  While bio-industries have primarily focused on flexible materials, and many replacements for petroleum-based polymers have already been developed, rigid materials are still a challenge. Additionally, due to its previously explained properties, bark makes packaging active, extending the shelf life of packed products and decreasing the amount of food waste.

There are several bark startups trying to revitalize bark waste by creating value-added products.  They are involved in extracting bark extracts, processing bark into raw materials for various industries, using bark as an active additive in adaptive packaging and even to produce polymeric materials.

Nikolay Semenov 

Chief Scientific Officer & Co-Founder of Bpacks 

Nikolay Semenov, Ph.D., is the Chief Scientific Officer at Bpacks, a startup that has developed the world’s first bark-based packaging technology to seamlessly replace plastic pellets. Nikolay is an expert in the field of materials science, boasting more than 15 years of experience in polymer research and over 35 scientific publications.  Visit https://bpacks.eco/ for more information.

Aleksandra Nešić

Head of Innovations at Bpacks

Aleksandra Nešić is an experienced scientist and entrepreneur, and the Head of Innovations at Bpacks. With over 22 scientific publications to her name, she leads the development of new, high-performance, bio-based packaging materials. Aleksandra has a Ph.D. in Materials Engineering from the University of Novi Sad, Faculty of Technology, and is driven by the idea of promoting female entrepreneurship in deeptech. Prior to Bpacks, she launched the app UseAllFood, which addressed the pressing issue of food waste. Visit https://bpacks.eco/ for more information.