Optimum synthesis of polyhydroxybutyrate-Co₃O₄ bionanocomposite with the highest antibacterial activity against...

Increased multidrug resistant (MDR) bacteria are considered one of the most challenging problems of the present century. The present study aimed to identify the optimum conditions for synthesis of Polyhydroxybutyrate-Co₃O₄ bionanocomposite with the highest antibacterial activity via in situ synthesis. Nine experiments with different amounts of polyhydroxybutyrate (PHB) biopolymer and Co₃O₄ nanoparticles and different stirring times were designed using Taguchi method. The antibacterial activity of synthesized nanocomposites against Staphylococcus aureus and Escherichia coli was evaluated using colony forming units (CFU) and disc diffusion methods. The characterizations of products were studied by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The synthesized bionanocomposites completely prevented the growth of bacteria under the conditions of experiments 5 (Co₃O₄ 4 mg/ml, PHB 1 mg/ml and stirring time: 90 min) and 9 (Co₃O₄ 8 mg/ml, PHB 2 mg/ml and stirring time: 60 min). The results showed that nanocomposite formation improved structural properties, thermal stability and antibacterial activity. PHB-Co₃O₄ bionanocomposite can be used in various fields of pharmacy, medicine and dentistry due to its desirable antibacterial properties.