Bioplastic (Polyhydroxybutyrate) Synthesis Using Orange Wastes by the Marine Bacterium Bacillus sp. Caspian04

Abstract

The production and development of bioplastics are necessary to solve the crisis originating from the accumulation of non-biodegradable plastics in the environment. This study aimed to synthesize polyhydroxybutyrate (PHB) using orange wastes by the bacterium separated from the Caspian Sea. Seven PHB synthesizing bacterial isolate were isolated from Caspian Sea water. The initial screening for PHB synthesis was performed with a dye-based method. The most powerful marine bacterium with the synthesis of 1.73 g/L PHB was identified via 16S rRNA gene sequencing as Bacillus sp. Caspian04 and its nucleotide sequence was preserved with the accession number OR999904.1 in GeneBank. PHB synthesis increased in the presence of ammonium chloride, 4% orange wastes extract, and 3% NaCl, at temperature of 35 °C and pH 8.0. Using the orange wastes extract (4% w/v) led to the synthesis of 5.22 g/L PHB, which can help reduce the cost of PHB synthesis. FTIR, ¹H NMR, ¹³C NMR, XRD, and TGA were used to evaluate extracted PHB’s characterization. The present study is the first attempt to bioplastic synthesis by bacteria isolated from the Caspian Sea. Furthermore, with the biotechnological production of PHB from orange wastes by Bacillus sp. Caspian04, the way will be paved for the development of management strategy of solid wastes and highlights the role of marine bacteria in the production of polymers with commercial value.