A process for the production of expandable pellets with bulk density from 500 to 800 kg/m 3 comprising polylactic acid, comprising the following steps: a) melting and incorporation by mixing of the following components: i) from 59.9 to 79.9% by weight, based on the total weight of components i to iii, of polylactic acid, ii) from 20 to 40% by weight, based on the total weight of components i to iii, of a polybutylene succinate, polybutylene succinate-co-adipate, polybutylene succinate-co-sebacate, polybutylene adipate-co-terephthalate, or polybutylene sebacate-co-terephthalate, iii) from 0.1 to 2% by weight, based on the total weight of components I to iii, of a chain extender, and iv) from 0 to 10% by weight, based on the total weight of components i to iii, of one or more additives, b) incorporation by mixing of v) from 3 to 7% by weight, based on the total weight of components i to iv, of a physical blowing agent into the polymer melt by means of a static or dynamic mixer at a temperature of at least 140°C, c) discharge through a die plate with holes, the diameter of which at the exit from the die is at most 1.5 mm, and d) underwater pelletization of the melt comprising blowing agent directly downstream of the die plate at a pressure in the range from 1 to 25 bar, and e) coating of the resultant pellets vi) with from 0.1 to 0.45% by weight, based on the total weight of the pellets, of amorphous polylactic acid, which is applied to the pellets by means of an aqueous dispersion. a) melting and incorporation by mixing of the following components: i) from 59.9 to 79.9% by weight, based on the total weight of components i to iii, of polylactic acid, ii) from 20 to 40% by weight, based on the total weight of components i to iii, of a polybutylene succinate, polybutylene succinate-co-adipate, polybutylene succinate-co-sebacate, polybutylene adipate-co-terephthalate, or polybutylene sebacate-co-terephthalate, iii) from 0.1 to 2% by weight, based on the total weight of components I to iii, of a chain extender, and iv) from 0 to 10% by weight, based on the total weight of components i to iii, of one or more additives, i) from 59.9 to 79.9% by weight, based on the total weight of components i to iii, of polylactic acid, ii) from 20 to 40% by weight, based on the total weight of components i to iii, of a polybutylene succinate, polybutylene succinate-co-adipate, polybutylene succinate-co-sebacate, polybutylene adipate-co-terephthalate, or polybutylene sebacate-co-terephthalate, iii) from 0.1 to 2% by weight, based on the total weight of components I to iii, of a chain extender, and iv) from 0 to 10% by weight, based on the total weight of components i to iii, of one or more additives, b) incorporation by mixing of v) from 3 to 7% by weight, based on the total weight of components i to iv, of a physical blowing agent into the polymer melt by means of a static or dynamic mixer at a temperature of at least 140°C, c) discharge through a die plate with holes, the diameter of which at the exit from the die is at most 1.5 mm, and d) underwater pelletization of the melt comprising blowing agent directly downstream of the die plate at a pressure in the range from 1 to 25 bar, and e) coating of the resultant pellets vi) with from 0.1 to 0.45% by weight, based on the total weight of the pellets, of amorphous polylactic acid, which is applied to the pellets by means of an aqueous dispersion.