Fed-batch production and characterization of polyhydroxybutyrate by Bacillus megaterium LVN01 from residual glycerol

Abstract

The operating conditions of polyhydroxybutyrate (PHB) production processes are among the factors that most influence yields. In this study, we evaluated PHB production synthesized by Bacillus megaterium LVN01. Batch and fed-batch cultures were used to produce PHB from residual glycerol. For this, dry cell weight (DCW) and PHB productivity were analyzed at a preliminary stage by central composite design using batch systems under different temperature, C/N ratio, and fermentation time conditions. The maximum PHB productivity occurred at 30.8 °C, 44.9 mol mol-1, and 39.9 h. The same conditions were tested for studies in fed-batch culture. Fed-batch experiments were comparable to each other, where the DCW was around 1.9 g L-1, with PHB productivities of 29.5 mg L-1 h-1 and 35.6 mg L-1 h-1 for bioreactors of 5 L and 14 L, respectively. The PHB was characterized by NMR, FTIR, DSC, TGA, and DTG analys