Advancing the Bio-Based Economy with LCAs on (Poly)Lactic Acid

Enabling the Bio-Based Economy with Transparent Environmental Data

The transition toward a bio-based economy is at the heart of the European Commission policy agenda. Through its Bioeconomy Strategy, the EU aims to reduce dependence on fossil resources, stimulate sustainable biomass use, and foster innovative bio-based materials such as lactic acid and polylactic acid (PLA).

However, bio-based does not automatically mean low impact. Life cycle impacts such as agricultural production, energy demand and transport logistics can significantly influence environmental performance.

Robust, transparent Life Cycle Assessment (LCA) is therefore essential. Only with sound methodological choices and high-quality data can companies demonstrate credible environmental benefits and identify meaningful improvement opportunities.

Over the past year, we have supported two leading players in the lactic acid and PLA value chain with cradle-to-gate assessments, each addressing different but complementary challenges.

Our Experience: LCA on Lactic Acid and Polylactic Acid (PLA)

At RDC Environment, we recently supported leading actors in the (poly)lactic acid value chain with cradle-to-gate environmental assessments, each tailored to their specific strategic questions.

• We conducted a Product Carbon Footprint (PCF) study on lactic acid products.
• We performed a multi-criteria cradle-to-gate LCA of polylactic acid (PLA) production.

Both studies focused on cradle-to-gate impacts (from raw material extraction through production). However, in the polylactic acid (PLA) production study we also compared the impacts of mechanical and chemical recycling, providing insights into the advantages and trade-offs of each technology.

Addressing Key Methodological Challenges

LCAs of lactic acid and PLA systems involve complex methodological considerations.

1. Multi-output fermentation processes

Like most bio-based systems, the manufacturing process generates multiple co-products, meaning that robust allocation is essential to correctly assign environmental impacts. The fermentation of glucose into lactic acid generates valuable co-products, including:

• Microbial biomass
• Gypsum (from the purification stage)

According to ISO 14044 guidelines, allocation should be avoided whenever possible by dividing the model into more smaller unit processes. However, sometimes the data is simply not available to do so. In the polylactic acid (PLA) production study, the fermentation process cannot be physically subdivided into independent sub-processes for each output. System expansion is theoretically possible but requires additional assumptions about substituted products.

Therefore, economic allocation was selected as the most relevant approach. The process is primarily operated to produce lactic acid for its economic value, not gypsum or microbial biomass. Economic allocation therefore better reflects the underlying production rationale compared to mass allocation.

2. Treatment of biogenic carbon

Within a cradle-to-gate scope, the uptake of biogenic carbon during the agricultural phase can lead to a substantial reduction in reported climate change impacts. Biomass absorbs CO₂ while growing, which is accounted for as a temporary carbon removal in the product system.

However, at the end of life (EoL), this biogenic carbon is typically released back into the atmosphere through degradation, incineration or other treatment processes. As these types of products do not result in long-term carbon storage, the initial uptake is effectively offset over the full life cycle. Consequently, no permanent carbon credit can be claimed.

Therefore, when presenting results for the climate change indicator where biogenic carbon is included, transparent communication is essential is key. Results should always be presented in disaggregated results that clearly distinguish between cradle-to-gate fossil emissions and the contribution of biogenic carbon uptake.

Assessing Recycled versus Virgin PLA

As part of the study for polylactic acid (PLA) production, we also evaluated the environmental performance of recycled PLA compared to virgin PLA production.The assessment was performed over five different cycles, reflecting a realistic material cascade:

• Cycle 1 : virgin PLA production
• Cycles 2–4: Mechanical recycling
• Cycle 5: Chemical recycling

For each cycle, we explicitly accounted for the progressive reduction in material quality compared to virgin PLA. Mechanical recycling can maintain polymer functionality for several loops, but with gradual degradation in mechanical properties. By the fourth cycle, the material quality was considered too low for further mechanical recycling, making chemical recycling the most appropriate recovery route to restore polymer performance.

The results clearly demonstrate that, for most environmental indicators, recycled PLA performs significantly better than virgin PLA. Avoiding primary biomass cultivation, fermentation and polymerisation steps leads to substantial reductions in impact, even when accounting for recycling-related energy use and processing.

These findings underline the importance of developing a strong and efficient recycling infrastructure for bio-based plastics. Closing the loop is essential to fully realise the environmental benefits of PLA, in line with the objectives of the European Commission Bioeconomy Strategy and the EU’s Circular Economy ambitions.

The Importance of a Strong Technical Partner

Bio-based value chains are inherently complex. From agricultural inputs to fermentation, polymerisation, allocation decisions and recycling scenarios, methodological rigor is critical.

Companies investing in bio-based materials need:

• Transparent and defensible LCA models
• Alignment with European methodological standards
• Sensitivity analyses to test key assumptions
• Clear identification of environmental hotspots

By combining technical expertise with a deep understanding of bio-based systems, we support our clients in making informed decisions, strengthening sustainability claims, and aligning with Europe’s transition toward a resilient bio-economy.