Eco-Friendly Alternatives to Plastics Key to Sustainability Efforts: Are Biodegradable Plastics a Solution?

The presence and accumulation of microplastics in our ecosystem are well-documented, and recent evidence suggests they have detrimental effects on various biological processes. As we continue to discover microplastics in our lungs, arteries, and even placentas, we are still learning about their impact on the environment and human health. 

It is the ubiquity of plastic usage by humans that has led to microplastics, which tend to persist in the environment. Microplastics are tiny fragments, generally measuring between 5 millimeters (mm) and 500 micrometers (µm) in size, shed by everyday plastic products. 

These particles originated from bottles, bags, packaging, and other plastic sources, as well as tire wear, synthetic textiles, and microbeads from personal care products. Microplastics are usually formed through a variety of physical and chemical processes, including abrasion, UV degradation, manufacturing processes, and physical or chemical-induced fragmentation.

The accumulation of microplastics in the natural environment, including oceans, precipitation, and soil, is due to the chemical nature of petroleum-based plastic polymers. These polymers are large molecules consisting of many smaller ones called monomers. These widely used plastics are usually inaccessible to biological processing. 

Being nearly indestructible, taking anywhere from decades to centuries to break down, there is a growing need for an alternative to traditional petroleum-based plastics and microplastics. An answer to this solution is to develop plastics that do not generate persistent microplastics as part of their normal life cycle. 

Even if plastic is properly collected and recycled, it still generates microplastics as part of normal wear from everyday use or as a consequence of recycling or washing processes. So, in order to prevent this, we need to develop new plastic materials that are completely biodegradable, which means they decompose quickly by the action of living organisms in the environment.

So, to help with this, a new study by Algenesis Corporation and scientists and professors at the University of California San Diego created a plant-based polymer that biodegrades at the microplastic level within seven months.

Biodegradation is the process by which polymers are broken down into simpler molecules by microbes. These molecules can then be used as a source of carbon to produce biomass. However, for that to happen, the polymer needs to have chemical bonds, mainly in its primary backbone structure.

This is because they are then physically accessible to enzymes that naturally recognize these bonds as substrates. The underlying monomer molecules released through this enzymatic cleavage can then be consumed by microorganisms.

In our natural environment, this entire process is usually executed by a group of microbes such as bacteria and fungi. These microbes secrete hydrolytic enzymes, which break the polymer to release different oligomers and monomers to be utilized by microbes as a carbon nutrient source. 

Catabolism of polymer-derived monomers and oligomers happens next, which involves the breakdown of complex molecules. This process results in the production of organismal biomass and CO2 via respiration.  

The thing is, while biobased materials can be derived from natural renewable sources, their limited biodegradable ability makes them remain in the environment. Also, this persistence can be due to chemical processing that makes them inaccessible to biological cleavage.

Biodegradable materials can indeed be produced from petroleum and other fossil resources since biodegradability depends on the material’s properties rather than its source.

Achieving the Impossible

The study, which received funding support from the Department of Energy (DOE), aims to find biodegradable replacements for materials that already exist. However, finding materials that do not collect in the environment is “not easy,” said co-author Michael Burkart, who is also the co-founder of Algenesis. 

The material science company’s patented Soleic™ technology is the world’s first renewable, fully biodegradable, and high-performance plastic material made from plants. Algenesis utilizes its material technology to produce shoes, surfboards, and footwear. According to Burkart, a professor of Chemistry and Biochemistry at UC San Diego:

“We’re just starting to understand the implications of microplastics. We’ve only scratched the surface of the environmental and health impacts.” 

Talking about their work, co-author and co-founder of Algenesis Robert Pomeroy, who, like Bukart, holds an equity position in the company and serves as a professor of chemistry and biochemistry, noted that they first created algae-based polymers more than half a decade ago. They understood that this polymer would be completely biodegradable, capable of “disappearing in the compost.”

For the first time, though, the team got the chance to measure it at the microparticle level. For that, they grounded the material into fine microparticles, and to confirm that it was being digested by microbes, the team used three different measurement tools.

A respirometer was the first tool, which was used to measure the carbon dioxide (CO2) released when the material is broken down by microbes. When comparing the breakdown of cellulose with the industry standard of one hundred percent biodegradability, the results showed that the plant-based polymer matches the cellulose at almost 100%.

The second tool used was water floatation, a method leveraging the fact that plastics are insoluble and flat in the water, making them easy to remove from the surface. Tests conducted at intervals of 90 and 200 days showed that almost all the petroleum-based microplastics were recovered. In contrast, for algae-based microplastics, only 32% recovered after nine days and a mere 3% after 200 days, demonstrating they’re highly biodegradable.

In the chemical analysis through gas chromatography/mass spectrometry (GCMS), the presence of monomers was detected, indicating that the polymer was being broken into its initial plant materials. 

“This material is the first plastic demonstrated to not create microplastics as we use it.” 

– Co-author Stephen Mayfield, co-founder of Algenesis

He further added:

“This is more than just a sustainable solution for the end-of-product life cycle and our crowded landfills. This is actually plastic that is not going to make us sick.” 

Although significant progress has been made, this is just the beginning. The next step involves adapting the new material for use with the existing manufacturing equipment built for traditional plastic. To this end, Algenesis has secured partnerships with several companies to make products using plant-based polymers. These collaborations include Trelleborg’s use of algae-based polymers in coated fabrics and the production of mobile phone cases with RhinoShield.

According to Burkart:

“When we started this work, we were told it was impossible. Now, we see a different reality. There’s a lot of work to be done, but we want to give people hope. It is possible.” 

Are Biodegradable Plastics the Future?

As we can see, the plastic sector is undergoing a transformation. This is important because plastic accounts for about 14% of our waste, and the vast majority of it ends up in the sea. Statistically speaking, we currently produce over 350 million metric tons of plastic waste per year, which is projected to reach one billion metric tons by 2060 if no changes are made to current policies.

Looking at the life cycle of most plastic materials reveals that 79% of all plastic produced gets dumped into landfill sites or reaches the environment, while only 12% is incinerated and 9% is recycled. Despite a considerable increase in recycling over the last four decades, non-fiber plastic recycling is stuck at 18%, with almost no textile fibers recycled. This stagnation is largely due to the limitations of the dominant form of recycling, which is all about converting waste plastics into new shapes through heat & mechanical force, where input quality is of importance. 

Amidst this backdrop, more and more companies around the world are taking steps to reduce the use of conventional plastic and replace it with more sustainable and environmentally responsible alternatives.

Biodegradable plastics involve bioplastics whose components are derived from renewable raw materials and plastics with biodegradable additives to improve their biodegradation.

Bioplastics are typically manufactured from bio-based polymers and stand to contribute to more sustainable commercial plastic life cycles. Here, polymers are made from renewable or recycled raw materials. Bio-based plastics tend to have a lower carbon footprint compared with fossil-based plastics. They also demonstrate advantageous material properties and can further be compatible with existing recycling streams.

All of this, along with growing awareness, research, and investment in the plastics industry, has led to the increasing presence of biodegradable plastics in our daily lives.

While we are far from meaningfully removing conventional plastic from our lives, many encouraging moves are being made. This includes finding biodegradable materials to manufacture products. Of course, it is hard to replace plastic in many applications, but in the near future, many products will be manufactured in a more eco-friendly manner. 

Environmentally friendly products have gained the most popularity in the food packaging sector, which accounts for approximately 39% of the total plastics produced. This clearly highlights the great scope for biodegradable plastics in the industry. For example, depending on the product, plastic bottles could be substituted with biodegradable materials, finding applications not just in food packaging but also in nutraceuticals.

Food trays are another good example (in addition to spoons, teaspoons, forks, and cups) where the use of biodegradable materials could make it possible to dispose of both the container and its contents in a single garbage can. Other products embracing biodegradable materials include coffee capsules, bags for fruit and vegetables, and garbage bags.

Biodegradable plastics offer a wide range of possibilities for manufacturing a diverse range of packaging while better serving the needs of many packaging applications, such as flexibility, printability, and barrier enhancements.

Recent data indicates that the worldwide market for biodegradable packaging has enormous growth potential; in 2022, it was valued at about $87 billion, and by 2029, it is projected to expand at a CAGR of 6.96%. And among all subsegments, plastic is the most lucrative and is predicted to expand at a faster pace than any other material type.

In particular, bioplastic, a promising alternative to petroleum-based polymers, has the potential to lessen both our dependency on fossil fuels and the emissions that contribute to climate change.

The most common biodegradable plastics now available are derived from starch or cellulose, including polylactic acid (PLA), poly-3-hydroxybutyrate (PHB), and polyhydroxyalkanoates (PHA). These materials are often used in the beverage, pharmaceutical, personal, and home care industries, as they are recyclable and biodegradable.

Beyond packaging, biodegradable plastics can find their application in the agriculture industry, where they can be used in mulch, which is pretty expensive to recycle. Compostable mulch here would eliminate the need to collect the waste as it would disappear in a few months without leaving microplastics that would persist for so many decades.

While there are many benefits and applications, biodegradable plastics have trade-offs in terms of higher costs and negative agricultural impacts. However, emerging biological and chemical methods, technological advances, financial incentives, and clear regulations can help with the large-scale application of bioplastics and bring sustainable impact.

As such, researchers are actively investigating better materials and cleaner production methods for enhanced properties and new-generation applications. At 43.5%, Europe is currently leading the commercial manufacturing of bioplastics, which is projected to reach 7.6 million tonnes by 2026. 

Conclusion

After years of studies, it is now well-known that microplastics accumulate in all physical environments, such as water bodies, soil, and precipitation, and are even dispersed in the air. Due to their ubiquity, microplastics are now part of the food chain, and evidence suggests they can cause significant harm to humans, animals, and ecosystems.

This has spurred research into biodegradable materials, which present a more environmentally friendly alternative to traditional plastics. In addition to the development of new materials, efforts are underway to implement universal standards. Moreover, there is a need for behavioral changes towards using less plastic and increasing the use of products made from bioplastics.  

Together, they certainly have the potential to bring a positive impact by mitigating the plastic waste crisis and carbon emissions. However, it’s important to note that even biodegradable plastic needs proper composting conditions to ensure that it lives up to its promise. Overall, we are making gradual steps towards a greener future.

Click here for the list of the five best bioplastics companies.