Thermoplastic starch (TPS) is starch from corn, potato or other crops that has been plasticised and blended with biodegradable polyesters such as PBAT or PLA so it can be extruded into film and moulded parts.
It replaces PE carrier bags, produce bags, bin liners, agricultural mulch film, cutlery and food-service items. The reference producer is Novamont (Italy) with its Mater-Bi range; every grade is certified EN 13432 and ASTM D6400 for industrial composting and some grades are certified home compostable. Novamont states renewable content of up to 100 percent, but many grades are far lower because of the fossil-based PBAT they contain.
End of life is industrial composting, with home composting for specific grades only. The University College London (UCL) Big Compost Experiment found that compostable bags frequently fail to break down in real home compost heaps, so the disposal route matters more than the certificate.
Drawbacks: often blended with fossil PBAT, so always check the biobased percentage; lower strength and moisture resistance than PE; certified compostable bags still need an organics collection that accepts them. Cost is a premium over PE but no verified figure was found.