Carob pod water extracts as feedstock for succinic acid production by Actinobacillus succinogenes 130Z

Carob pods are a by-product of locust bean gum industry containing more than 50% (w/w) sucrose, glucose and fructose. In this work, carob pod water extracts were used, for the first time, for succinic acid production by Actinobacillus succinogenes 130Z. Kinetic studies of glucose, fructose and sucrose consumption as individual carbon sources till 30 g/L showed no inhibition on cell growth, sugar consumption and SA production rates. Sugar extraction from carob pods was optimized varying solid/liquid ratio and extraction time, maximizing sugar recovery while minimizing the extraction of polyphenols. Batch fermentations containing 10–15 g/L total sugars resulted in a maximum specific SA production rate of 0.61 Cmol/Cmol X.h, with a yield of 0.55 Cmol SA/Cmol sugar and a volumetric productivity of 1.61 g SA/L.h. Results demonstrate that carob pods can be a promising low cost feedstock for bio-based SA production.