The ecological impact of non-bio-based plastics has accelerated the demand for natural bio-based resins like polyhydroxyalkanoates (PHAs), biodegradable compounds with industrial and medical applications. This study focuses on the isolation and molecular identification of PHB-synthesizing bacteria from mangrove forest ecosystems in Kerala, India. Thirty-two microbial species were isolated from four mangrove rhizospheric soil sites. Sudan Black B and Nile Blue A staining confirmed lipid inclusions and PHB accumulation in sixteen isolates. Bacillus velezensis, identified through Crotonic acid quantification and 16S rRNA sequence analysis, showed the highest PHB concentration. Phylogenetic analysis revealed Bacillus species dominated the