Polylactic Acid (PLA): The environmentally responsible plastic
Read our guide to PLA bioplastic to learn all about PLA material including how it is produced, the environmental and economic advantages of PLA and how it fits into the circular economy.
What is PLA bioplastic?
Polylactic acid or polylactide (PLA) is a polyester derived from renewable biomass, typically from fermented plant starch, such as corn, cassava, sugarcane or sugar beet pulp. While the feedstock currently doesn’t compete with food production, manufacturers are already investigating the use of non-agricultural feedstocks. The environmental advantages of PLA bioplastics over those plastics derived from petroleum are measurable and significant.
How PLA is produced
PLA is a polyester (polymer containing the ester group) made with two possible monomers or building blocks: lactic acid, and lactide. Lactic acid can be produced by the bacterial fermentation of a carbohydrate source under controlled conditions. In the industrial-scale production of lactic acid, the carbohydrate source of choice can be corn starch, cassava roots, or sugarcane, making the process sustainable and renewable.
Research is ongoing to come up with even more eco-friendly and cheaper methods of producing PLA. In addition, the agricultural produce itself, crop residues such as stems, straw, husks, and leaves, can be processed and used as alternative carbohydrate sources. The residue that cannot be fermented can be used as a heat source to lessen the use of fossil fuel-derived hydrocarbons.
Environmental advantages of PLA
PLA is biodegradable under commercial composting conditions and will breakdown within twelve weeks, making it a more environmentally choice when it comes to plastics in contrast to traditional plastics which could take centuries to decompose and end up creating microplastics.
The manufacturing process for PLA is also more environmentally friendly than that of traditional plastics made from finite fossil resources. According to research, the carbon emissions associated with PLA production are 80% lower than that of traditional plastic (source).
PLA can be recycled as it can be broken down to its original monomer by a thermal depolymerization process or by hydrolysis. The outcome is a monomer solution that can be purified and used for subsequent PLA production without any loss of quality.
However, the recycling infrastructure for PLA hasn’t been scaled up yet, mainly because end markets for the recycled material haven’t been developed.
While recycling PLA might be a viable solution in the future, we currently recommend composting as a preferred end-of-life option, especially as foodservice packaging is often contaminated with food scraps, making recycling impractical.
There are plenty of advantages to PLA, but there are some disadvantages, too. These include the environmental impact on land and water than growing crops and using fertiliser causes (even though in 2019, bioplastics represented 0.016% of total land use and 2024 projection is 0.021%, see next section (source).
Additionally, PLA plastic packaging can be more expensive than its conventional plastic counterparts due to the number of steps required in the production process. However, as PLA becomes more widely available efficiencies of scale come into play which means the cost can decrease.
PLA: from plants to the soil, a truly circular option
The production of bioplastic has little to no effect on food prices or supply. In 2018 the global production capacities for bioplastics amounted to around 2.1 million tonnes. This translates into approximately 790,000 hectares of land. The surface area required to grow sufficient feedstock for today’s bioplastic production is therefore about 0.01% of the global agricultural area of 5 billion hectares. This ratio correlates with the size of an average cherry tomato next to the Eiffel Tower (based on market data by EUBP/IfBB/nova-Institute, 2014).
In 2023, assuming continued high growth in the bioplastics market, at the current stage of technological development, a market of around 2.6 million tonnes accounting for about 975,000 hectares of land could be achieved. This market equates to approximately 0.016% of the global agricultural area.
In fact, leading PLA manufacturer, Natureworks, has announced that 100% of its feedstock will be third-party certified sustainable feedstock by 2020.
NatureWorks was the first biopolymers manufacturer to become certified to the new ISCC PLUS standard in 2012, and currently has more than 40% of its agricultural feedstock certified. At full capacity, more than 90 farms will be involved in the program by 2020.
Every farm entering the program receives training in adhering to the ISCC PLUS certification’s principles, which are the following:
- Protect highly biodiverse and high carbon stock areas.
- Implement best agricultural practices for the use of fertilizers and pesticides, irrigation, tillage, soil management, and the protection of the surrounding environment.
- Promote safe working conditions.
- Comply with human, labour, and land rights.
- Comply with laws and international treaties.
- Implement good management practices and continuous improvement.
Natureworks is also committed to feedstock diversification, and to using the most abundant, locally available, and sustainable source of biobased carbon, wherever they produce. They are also committed to critically assessing and assuring the sustainability of each and every feedstock they use.
Natureworks is now developing PLA from lignocellulosic: sugars from bagasse, wood chips, or straw, as well as assessing CO2 (carbon dioxide) to lactic acid technology and CH4 (methane) to lactic acid technology (read more).