Lactic acid and PLA

Lactic acid is fermented from sugar; polymerised, it becomes PLA, the largest compostable bioplastic, worth about $2 billion and costing roughly double fossil plastics.

Bio-based chemicals · Fermentation products · No. 110

• Single chemical
• Feedstock: Crops and biomass
• PLA: not published by the sources reached; a few hundred kt a year, within 1.67 Mt of all bioplastics produced in 2025 (European Bioplastics). Lactic acid: about 1-2 Mt a year (indicative)
• 0.6 t CO₂e per t
• HS 291811, 390770

Bacteria that sour milk can also make a plastic cup that composts, starting from a bowl of sugar.

Chart: Illustration: Lactic acid and PLA

Where it comes from

Chart: Map of where it comes from

Bacteria ferment sugar into lactic acid, which is turned into a ring-shaped lactide and strung into PLA; each tonne needs about 1.5-1.7 t of sugar.

Three things to know

1. All bioplastics together were only about 0.5% of the 431 Mt of plastics made in 2025.
2. Balrampur Chini is building an 80 kt a year PLA plant in Uttar Pradesh for Rs 2,850 crore.
3. PLA softens at about 55-60 C unless crystallised, which rules it out for hot drinks without extra treatment.

The journey

1. 1 CropCane, maize or cassava supplies the sugar
2. 2 FermentationBacteria turn glucose into L-lactic acid
3. 3 LactidePurified acid cracked into a ring monomer
4. 4 PolymerisationRing-opening makes PLA pellets
5. 5 ProductsCups, films, tea bags, 3D-printing filament

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