Consolidated bioprocessing of inulin-containing feedstock to succinic acid by newly isolated Enterobacter sp. GAP1

• Enterobacter strain which can directly utilize inulin was isolated from soil environment for succinic acid biosynthesis. • Co-fermentation cultures were done using seven carbon sources including inulin and glycerol. • The possibility of submerged and semi-solid fermentation was demonstrated, depending on the consistency of the inulin-containing substrate (liquid or solid-state biomass). • Up to 29.4 g/L SA from inulin Y SA = 0.43 g/g; P SA = 0.153 g/L*h and 17.9 g/L from ground and dried JA tubers Y SA = 0.47 g/g; P SA = 0.147 g/L*h were obtained. • Jerusalem artichoke was first used as a non-grain substrate for SA production in consolidated bioprocess (CBP). The novel Enterobacter sp. GAP1 strain was found to ferment inulin-containing carbohydrates in Jerusalem artichoke (JA) without the need for acidic or enzymatic pretreatment prior to fermentation. The GAP1 strain also possesses an efficient ability to produce succinic acid (SA). Using inulin as a carbon source in a liquid medium produced 29.4 g/L of SA. Using ground and dried JA tubers resulted in a SA concentration of 17.9 g/L, while adding freshly squeezed JA tuber juice resulted in a concentration of 24.7 g/L. In addition to tests using liquid media, the possibility of producing SA under conditions of limited water availability was also investigated, achieving a concentration of 27.7 g/L. Notably, the use of the Enterobacter sp. GAP1 strain is the first reported instance of a consolidated bioprocess for producing SA from inulin-containing materials both submerged and semi-solid state fermentation approach.