Environmental needs require intensive efforts concerning recycling, reprocessing and reuse of polymer materials to avoid pollution of soil and water. Also biodegradable polymers like polylactide (PLA) increasingly attain the plastics waste streams because of their application in packaging and other short term usages. Although PLA is one of the bio-based and simultaneously biodegradable polymers, the biodegradation needs a longer time, thus PLA has to be separated from the waste streams and recycled too, either in a mixed plastics fraction or in a fully separated lot. The assessment of recyclability can be performed by the analysis of its thermostability and viscoelastic behavior under specific consideration of the molecular degradation mechanisms running in this biobased thermoplastic polyester. Multi-processing experiments were performed using a laboratory single screw extruder with a 19/25D screw with varied cylinder temperature profile and screw rate. Measurements of molecular mass as well as thermogravimetric and rheological studies were performed for the characterization of changes of the molecular structure and flow properties in dependence on the number of processing cycles, temperature and screw rate as well as moisture. Undried and dried PLA pellets were inserted in the experiments. It could be shown that multiple reprocessing of PLA lead to drastic loss of molecular weight and viscosity with increasing number of extrusion cycle and temperature. Water accelerates the molecular destruction of this bio-polyester essentially because of hydrolytic determined degradation mechanisms, while the heat sensitivity of the dried PLA is higher than the undried. Finally, the so-called plastics recycling cascade is applicable for PLA recycling too, i.e. type-clean and low polluted PLA fractions should be recycled by means of melt processing supported recycling processes, whereas mixed and strong polluted fractions containing PLA should be conveyed to energetically use.