PHB (Polyhydroxybutyrate) is a non-toxic and biodegradable microbial biopolymer with thermoplastic-like properties with growing relevance for biomedical applications. However, PHB is inherently brittle, and requires a plasticizer to enhance mechanical performance. In the present study, a fully natural biopolymer with anti-quorum sensing and bactericidal properties was synthesized and evaluated for its physico-mechanical properties and biocompatibility. PHB films were fabricated with Coconut oil (CO) as plasticizer resulting in substantial improvement in flexibility, with elongation at break increasing from 1.713% in pure PHB films to over 8% in the CO plasticized blend. To confer bioactive property, Thyme essential oil (TEO) was incorporated, which also improved wettability, protein adsorption, and resulted in average surface roughness of 338.215 nm. This blend showed enhanced biocompatibility with L929 fibroblasts. In vitro TEO release studies revealed initial burst release followed by sustained release over 48 hours indicating an early and prolonged antimicrobial activity. The TEO blend showed effective bactericidal and anti-quorum activity with Chromobacterium violaceum confirming preservation of bioactivity during blend fabrication. The sustainable, antimicrobial biopolymer formulated in this work presents a promising candidate for development of eco-friendly biomedical products such as sutures, wound dressings and scaffolds.