Biodegradable polyester comprising: A) biodegradable aliphatic/aromatic copolyester (AAPE) comprising: a) an acid component comprising repeating units of: 1. 50 to 60 mol % of an aromatic polyfunctional acid; 2. 40 to 50 mol% of an aliphatic acid, at least 90 % of which is a long-chain dicarboxylic acid (LCDA) of natural origin selected from azelaic acid, sebacic acid, brassylic acid or mixtures thereof; b) at least one diol component; said aliphatic long-chain dicarboxylic acid (LCDA) and said diol component (b) having a number of carbon atoms according to the following formula: C LCDA • y LCDA / 2 + C b • y b > 7.5 where: - C LCDA is the number of carbon atoms of the LCDA and can be 9, 10 or 13; - y LCDA is the molar fraction of each LCDA on the total number of moles of LCDA; - C b is the number of carbon atoms of each diol component; - Y b is the molar fraction of each diol on the total number of moles of the diol component (b) said AAPE having: - a biodegradability after 90 days higher than 70%, with respect to pure cellulose according to the Standard ISO 14855 Amendment 1; - a density of equal to or less than 1.20 g/cc; - a number average molecular weight Mn of 40,000- 140,000; - an inherent viscosity of 0.8 - 1.5. B) chain extenders, in a quantity comprised between 0,05- 2,5 %; A) biodegradable aliphatic/aromatic copolyester (AAPE) comprising: a) an acid component comprising repeating units of: 1. 50 to 60 mol % of an aromatic polyfunctional acid; 2. 40 to 50 mol% of an aliphatic acid, at least 90 % of which is a long-chain dicarboxylic acid (LCDA) of natural origin selected from azelaic acid, sebacic acid, brassylic acid or mixtures thereof; b) at least one diol component; said aliphatic long-chain dicarboxylic acid (LCDA) and said diol component (b) having a number of carbon atoms according to the following formula: C LCDA • y LCDA / 2 + C b • y b > 7.5 where: - C LCDA is the number of carbon atoms of the LCDA and can be 9, 10 or 13; - y LCDA is the molar fraction of each LCDA on the total number of moles of LCDA; - C b is the number of carbon atoms of each diol component; - Y b is the molar fraction of each diol on the total number of moles of the diol component (b) said AAPE having: - a biodegradability after 90 days higher than 70%, with respect to pure cellulose according to the Standard ISO 14855 Amendment 1; - a density of equal to or less than 1.20 g/cc; - a number average molecular weight Mn of 40,000- 140,000; - an inherent viscosity of 0.8 - 1.5. a) an acid component comprising repeating units of: 1. 50 to 60 mol % of an aromatic polyfunctional acid; 2. 40 to 50 mol% of an aliphatic acid, at least 90 % of which is a long-chain dicarboxylic acid (LCDA) of natural origin selected from azelaic acid, sebacic acid, brassylic acid or mixtures thereof; 1. 50 to 60 mol % of an aromatic polyfunctional acid; 2. 40 to 50 mol% of an aliphatic acid, at least 90 % of which is a long-chain dicarboxylic acid (LCDA) of natural origin selected from azelaic acid, sebacic acid, brassylic acid or mixtures thereof; b) at least one diol component; - C LCDA is the number of carbon atoms of the LCDA and can be 9, 10 or 13; - y LCDA is the molar fraction of each LCDA on the total number of moles of LCDA; - C b is the number of carbon atoms of each diol component; - Y b is the molar fraction of each diol on the total number of moles of the diol component (b) - a biodegradability after 90 days higher than 70%, with respect to pure cellulose according to the Standard ISO 14855 Amendment 1; - a density of equal to or less than 1.20 g/cc; - a number average molecular weight Mn of 40,000- 140,000; - an inherent viscosity of 0.8 - 1.5. B) chain extenders, in a quantity comprised between 0,05- 2,5 %;