The use of bioplastic, such as polycaprolactone, to substitute conventional plastic remains a problem to solve. The bioplastic degradation time is still relatively low when compared to the rate of plastic consumption by the public. Therefore, exploration of indigenous bacteria with plastic-degrading potential is needed. This study aims to reveal the potential of indigenous bacteria isolated from Wonorejo Mangrove as plastic-degrading bacteria based on their growth in selective media and biofilm formation. Bacterial isolates obtained from water bodies and sediments of Wonorejo’s mangrove were inoculated on minimum salt media with the addition of 0.25% polycaprolactone as the sole carbon source and then incubated for four weeks to determine the bacterial growth based on its total number. The total number of bacteria was calculated by the direct counting method using a hemocytometer. The results indicated a slight decrease in the number of cells for each isolate. Isolate T1A.1 obtained from mangrove water samples encountered a decrease in the total number of bacteria by 2 times the initial number. Meanwhile, isolate T2.1, which was isolated from mangrove sediments, was decreased by 1.4 times from the initial number. However, the enumeration did not cover the cells that formed the biofilm, which was observed in this study. Based on the ability of the isolates to live in the minimum media and the biofilm formation indicated their potential as plastic-degrading agents, specifically for polycaprolactone. Identification and further studies of both isolates are needed to get a better insight into their potential as polycaprolactone-degrading agents.
