During the last century, excessive usage of plastic products has caused serious waste of energy and fossil resources. Moreover, inefficient waste management and inadequate recycling has resulted in high accumulation of plastics in the environment, having thus a significant impact on living organisms. Our purpose is the identification, isolation and characterization of plastic degrading microorganisms, as well as the secreted enzymes that take part in the biodegradation process. Another main goal is the designing of a novel host strain that could degrade multiple targeted plastic wastes (PHA, PET, PU, PS, PE), using metabolic engineering technology. In order to make the process more sustainable, the development of stabilized biocatalysis technologies, which can increase enzymatic activity, is also studied. Meanwhile, in terms of a circular economy plan, the exploitation of the degradation monomers and their conversion via microbial fermentation into useful biomolecules, such as bio-plastics, is investigated.