Valorization of organic waste with simultaneous biogas upgrading for the production of succinic acid

Increased awareness on environmental drawbacks of petroleum-based industries are promoting transition from fossil-based succinic acid to its bio-based alternative. However, due to low price of oil the economic feasibility of the bio-succinic acid production is still challenged. The current study focuses on valorization of organic fraction of household kitchen waste pretreated by enzymatic hydrolysis to produce succinic acid with process CO2 supply from biogas. The total sugar content of 119.3 +/- 1.7 g/L with 15% xylose and 85% glucose was obtained by enzymatic hydrolysis. Moreover, based on substrate inhibition tests with glucose, lower glucose concentration was more efficient in terms of succinic acid yield and production rate. Through fermentation of hydrolysate (17 g/L sugar) with Basfia succiniciproducens succinic acid was produced in 0.46 +/- 0.0 and 0.25 +/- 0.0 g(sA)/g(glucose), using magnesium carbonate and raw biogas, respectively. Batch fermentation in the bioreactor with raw biogas resulted in glucose consumption rate of 2.22 +/- 0.25 g(Glu)/g(DCW).h, and 8.0% (v/v) of CO2 decrease compared to raw biogas. This study shows a proof of concept of organic waste valorization and raw biogas application in succinic acid production.