Everyone by now knows of the damage that plastic can do to our planet. Whether it be the abundance of plastic in the ocean harming marine life, or the inability to biodegrade resulting in plastic littering the natural environment, we collectively agree that we need to phase out single-use plastics. A lesser-known drawback of plastic is the high emissions produced during their production. Listen to the short audio piece below to find out about plastic’s emissions, and the surprising truth about alternatives to plastic too(1).
So from the perspective of global warming, plastic production is a large contributor to greenhouse gas emissions. However the alternatives to plastic, such as paper and glass, actually create even more emissions in their production! Obviously this does not mean plastic should continue to be used, due to the environmental impacts such as seen in the ocean, although as heard in the audio piece global warming poses a very significant threat to the ocean (as well as to the rest of the planet)(1). As a result, we therefore need an alternative that can be used to produce our necessary materials, is able to biodegrade in oceans and on land while having low/zero carbon emissions in production. Though this sounds rather ambitious, it turns out we are closer to achieving this than you may think.
Newlight(2) is a company aiming to create exactly what the planet needs, an environmentally friendly alternative to plastic. In recent years they have had great success with their aim, and they have now created ‘AirCarbon’. AirCarbon is carbon negative, which is very beneficial, and is versatile in the sense that it can be used to make a vast range of materials and products, just like plastic. Additionally, it’s properties enable it to be used for other things, such as replacing leather and fibre. Unlike plastic, it biodegrades both in the sea and on land(2). You may expect that the process to produce AirCarbon is complicated and difficult to reproduce. However, they use something that nature uses every day in every ecosystem, including us.
AirCarbon is PHB (Polyhydroxybutyrate), a biodegradable polymer which is a part of the PHA (Polyhydroxyalkanoate) family. PHB is readily synthesised in nature by certain microorganisms. It is thought that they produce and store PHB for the same reason we store fat, for use as an energy source. Particularly, microorganisms found in the ocean were consuming methane and carbon dioxide and converting this to PHB. Newlight saw this and wanted to emulate the process on land to mass produce the PHB biomaterial. After years of work, they have developed a process which combines greenhouses gases with air in a saltwater solution to create PHB. The microorganisms are then collected and filtered, separating them from the PHB, which is dried and processed into pellets to give AirCarbon(2, 3).A similar production method of PHAs can be found in the paper here(4).
As touched on previously, PHB offers a great number of benefits compared to plastic. One of its main positives is its ability to biodegrade in virtually any environment, and when considering that it is carbon negative (takes CO2 out of the atmosphere as opposed to emitting any), it is clear to see why PHB is thought of as the leading alternative to plastic for the future(5). This has not gone unnoticed either, due to AirCarbon’s versatility it is able to be used for a variety of applications. Nike have recently formed a partnership with Newlight to reduce their carbon footprint and produce a range of carbon negative products that would previously have been made using plastic and leather(6).
As usual, this new technology comes with a high production cost. This is increased further since Newlight buy renewable gas and energy, which while great for the environment increases their costs(2). Due to AirCarbon’s properties, it isn’t able to be employed for every use. For example, in its biological production, PHB has a very regular structure where the individual polymer chains are able to pack together well forming the crystal structure. As a result of this however, the polymer is brittle and stiff. Despite this, the PHB production process can be modified to produce PHB-PHV, a similar polymer which uses PHV (polyhydroxyvalerate) making it less brittle, but vitally still biodegradable. The PHB-PHV is then able to be used in ways which AirCarbon is perhaps less suited to(7).
Overall, it is clear to see why AirCarbon (and PHB) is such a promising material for the future. It offers a crucially carbon negative alternative to plastic which is able to biodegrade or be melted down and reused multiple times for different purposes. Despite higher costs than plastic production currently, as the price of petroleum (used to make plastic) increases and the production process of AirCarbon is scaled up and refined, AirCarbon will prove to become both a more environmentally and economically friendly material(7). Undoubtedly in the future we will find even further ways to produce plastic alternatives for a variety of uses, so we can finally rid the world of damaging plastics.
Author: Oliver Pearce
Bibliography:
- Joyce C. Plastic Has A Big Carbon Footprint — But That Isn’t The Whole Story. 2019.
- Newlight. Newlight [Available from: https://www.newlight.com/.
- Bentley T. How Tiny Ocean Microorganisms Could Kill Your Plastic Fork 2021 [Available from: https://www.popularmechanics.com/science/green-tech/a36232993/carbon-negative-manufacturing/.
- Liu L-Y, Xie G-J, Xing D-F, Liu B-F, Ding J, Ren N-Q. Biological conversion of methane to polyhydroxyalkanoates: Current advances, challenges, and perspectives. Environmental Science and Ecotechnology. 2020;2:100029.
- McAdam B, Brennan Fournet M, McDonald P, Mojicevic M. Production of Polyhydroxybutyrate (PHB) and Factors Impacting Its Chemical and Mechanical Characteristics. Polymers (Basel). 2020;12(12):2908.
- Laird K. Newlight’s AirCarbon PHB offers carbon-reduction opportunities for Nike2021 18/09/2021.
- Gwynne J. Polyhydroxybutyrate 2021 [Available from: https://www.chemistryworld.com/podcasts/polyhydroxybutyrate/3005910.article.