Optimization of fermentation medium for succinic acid production using Basfia succiniciproducens

Abstract

The development of cost-competitive bioprocesses is dependent on the formulation of low cost and efficient fermentation medium. Thus, optimization of nutrient composition in fermentation media combining efficient metabolic product formation with cost-competitiveness is needed. Within this context, the main novelty of this study was to optimize the nutrient composition of a fermentation medium used for bio-based succinic acid production by the wild-type bacterial strain Basfia succiniciproducens JF4016 combining low cost with high succinic acid production efficiency. Two Plackett–Burman​ Designs, a central composite design and constraint optimization were sequentially implemented to estimate the optimum and cost-competitive fermentation medium composition. The two Plackett–Burman Designs identified NaH 2 PO 4 , Na 2 HPO 4 and NaCl as the most important medium components. Central composite design identified the optimum concentrations of NaH 2 PO 4 , Na 2 HPO 4 , NaCl, yeast extract and corn steep liquor leading to the highest productivity. Constraint optimization was employed to maximize productivity using constraints on the final succinic acid concentration, yield, by-products to succinic acid ratio and fermentation medium cost. Validation of the model predictions was carried out in a bioreactor culture at ca. 30 g/L initial glucose concentration. The optimum fermentation medium containing 19.4 g/L CSL, 9.2 g/L yeast extract, 3 g/L NaCl and 4.32 g/L sodium phosphates led to the production of 19 g/L succinic acid concentration, 0.62 g/g yield and 1.9 g/(L ⋅ h) productivity. • Experimental design to optimize fermentation medium for succinic acid production by Basfia succiniciproducens . • Succinic acid production reached 19 g/L with 0.62 g/g yield and 1.9 g/(L⋅h) productivity. • Reduced fermentation medium cost ($1.22/kg SA ) was estimated at the optimal medium composition.