Formulation and optimization of a novel media comprising rubber seed oil for PHA production

Formulation and optimization of a media comprising rubber seed oil1 (RSO) as a low cost substrate for polyhydroxyalkanoates (PHA) biosynthesis in the bacterial strain Bacillus cereus was implemented. The formulation study using general full factorial design concluded that 1.5% (v/v) RSO in distilled water is sufficient to obtain PHA content as high as 604.77 mg/g cell dry weight and a total yield of 2.16 g/L within a growth period of 72 h at 150 rpm. Response surface methodology based design was used for the optimization of production parameters. Accordingly, PHA content of 641.14 mg/g cell dry weight and a total PHA yield 2.56 g/L were obtained in 69.2 h with RSO concentration of 1.567% (v/v) and an agitation of 130 rpm. Characterization of the polymer was performed by Fourier transform infrared spectroscopy, X-ray diffraction crystallography, scanning electron microscopy, differential scanning calorimetry and thermogravimetric analysis. Scale up studies and industrialization of this media for PHA production will result in value addition to rubber seeds that are currently commercially insignificant.