Statistical optimization of physical process variables for bio-plastic (PHB) production by Alcaligenes sp.

► Utilization of cane molasses and urea for bio-plastic (PHB) production. ► Screening of PHB accumulating colony done by nile blue A staining. ► Optimum condition comprised: 34.5 °C temperature, 6.54 pH, 3.13 Hz agitation speed. ► PHB yield of 76.80% on dry cell mass obtained at optimized condition. ► PHB yield and productivity of 78% and 0.19 g L−1 h obtained on bioreactor.