Work

Synthesis, Structure, and Properties of Polyhydroxybutyrate Derived from Azotobacter Vinelandii N‐15

Year: 2025

Type: article

Abstract: Biodegradable polymers are of great interest in addressing the current pollution problem caused by synthetic petroleum‐based polymers. It is well known that various microorganisms synthesize and store high‐molecular‐weight polyhydroxyalkanoates in their cytoplasm as water‐insoluble inclusions. In this study, the bacterium Azotobacter vinelandii N‐15 strain is used for bioplastic production. The optimal polyhydroxybutyrate (PHB) yield (62% of biomass, 23.6 g L −1 dry cells) is achieved by cultivating the bacteria in Burke's medium with molasses as a carbon source (5 wt.%) at 30 °C, 220 rpm, for 50 h. The resulting polymer was characterized using thin‐layer chromatography, UV‐Vis, fourier transform infrared, nuclear magnetic resonance spectroscopy, gas chromatography, and X‐ray diffraction. The results confirmed that the polymer is PHB with a purity of 98.9%, a molecular weight of 1.2 MDa, a crystallinity of 73%, a melting point of 179 °C, a decomposition temperature of 275 °C, a density of 1.22 g cm − 3 , a melt flow index of 10 g 10 min −1 , a Shore hardness of 82, a tensile strength of 30 MPa, and a relative elongation at break of 4.5%. Thus, a bioplastic with properties suitable for practical applications is successfully obtained using molasses—a byproduct of sugar production.

Source: ChemistryOpen

DOI: 10.1002/open.202500150

Authors: Yang Liu, Dongwei Li, Xianghai Ran, Wei Nie, Ihor Semeniuk, Nataliia Koretska