A robust fed-batch feeding strategy independent of the carbon source for optimal polyhydroxybutyrate production

作者：Mozumder Md Salatul Islam^*; De Wever Heleen; Volcke Eveline I P; Garcia Gonzalez Linsey

来源：Process Biochemistry, 2014, 49(3): 365-373.

DOI：10.1016/j.procbio.2013.12.004

• Automatic substrate feeding
• Polyhydroxybutyrate (PHB)
• Fed-batch fermentation
• Biomass growth
• PHB accumulation
• Waste glycerol

A three-stage control strategy independent of the organic substrate was developed for automated substrate feeding in a two-phase fed-batch culture of Cupriavidus necator DSM 545 for the production of the biopolymer polyhydroxybutyrate (PHB). The optimal feeding strategy was determined using glucose as the substrate. A combined substrate feeding strategy consisting of exponential feeding and a novel method based on alkali-addition monitoring resulted in a maximal cell concentration in the biomass growth phase. In the PHB accumulation phase, a constant substrate feeding strategy based on the estimated amount of biomass produced in the first phase and a specific PEIB accumulation rate was implemented to induce PHB under limiting nitrogen at different biomass concentrations. Maximal cell and PHB concentrations of 164 and 125 g/L were obtained when nitrogen feeding was stopped at 56 g/L of residual biomass; the glucose concentration was maintained within its optimal range. The developed feeding strategy was validated using waste glycerol as the sole carbon source for PHB production, and the three-stage control strategy resulted in a PHB concentration of 65.6 g/L and PHB content of 62.7% while keeping the glycerol concentration constant. It can thus be concluded that the developed feeding strategy is sensitive, robust, inexpensive, and applicable to fed-batch culture for PHB production independent of the carbon source.

• 出版日期2014-3