Chemistry of bioplastic production by Alcaligenes faecalis NSBN10 using cane molasses: optimization and characterization

This study investigates the chemistry of bioplastic production by Alcaligenes faecalis strain NSBN10 using cane molasses as a low-cost carbon source. The bacterium capable of synthesizing polyhydroxybutyrate (PHB), a bioplastic, was screened using Sudan Black B dye and Nile Blue A staining, with the highest fluorescence level being observed for A. faecalis NSBN10. This strain was further identified through 16S rRNA gene sequencing. To optimize the bioplastic production, a statistically-based response surface methodology (RSM) was employed using a central composite design. The effects of cane molasses concentration (10–40 g/L), yeast extract content (0.1–2 g/L), and pH (6–9) on bioplastic yield and productivity were evaluated. The optimal conditions for the highest bioplastic yield (78.70%) were achieved with cane molasses at 25 g/L, yeast extract at 1.05 g/L, and a pH of 7.5, resulting in enhanced productivity. Fourier transform infrared spectroscopy (FTIR) analysis was used to characterize the bioplastic, confirming its composition. This study highlights the potential of utilizing cane molasses for cost-effective bioplastic production, with a focus on the underlying chemistry of the synthesis process.