Bioprocess development using organic biowaste and sustainability assessment of succinic acid production with engineered Yarrowia lipolytica strain

The utilization of crude waste streams and the development of novel bioprocessing routes are necessary in order to expand the industrial implementation of bio-based succinic acid production. This work focuses on the utilization of zero cost municipal organic biowaste for the production of bio-based succinic acid using the engineered yeast strain Yarrowia lipolytica PSA02004. Fermentation advances focused on pH regulation towards reduced NaOH requirements. Optimum initial carbon source concentration (100–120 g/L) in crude hydrolysates was estimated in shake flask cultures. Optimum k_Lα (183.2 h⁻¹) in fed-batch cultures resulted in 42.2 g/L succinic acid with 0.38 g/g yield and 0.84 g/L/h productivity. A two-stage pH regulation strategy was employed to enhance succinic acid production efficiency and reduce NaOH requirements. The gradual reduction of pH from 6 to 5.5 resulted in 54.4 g/L succinic acid with 0.44 g/g yield and 0.82 g/L/h productivity and 43% lower NaOH consumption. The minimum selling price of succinic acid was estimated at $2.7/kg and $2.94/kg at annual production capacity of 50,000 t when the production cost of organic biowaste derived sugars were considered at $10/t_TS and $110/t_TS, respectively. The global warming potential and abiotic depletion potential were estimated at 2.72 kgCO₂-eq/kg_SA and 33.4 MJ/kg_SA, respectively. Results showed that pH regulation is an important operating parameter towards the sustainable succinic acid production using municipal organic biowaste.