Bio-based succinic acid production from durian husk: A rising Southeast Asia agricultural waste

Abstract

The spiking availability of durian husk in Southeast Asia reveals a promising yet underutilized lignocellulosic biomass. Compositional characterization via National Renewable Energy Laboratories protocols (NREL) showed that durian husk contained 40.96% glucan, 9.51% xylan, and 26.48% of lignin. Enzymatic hydrolysis of durian husk was improved upon dilute sulfuric acid pretreatment. The optimal conditions for particle size and pretreatment duration were determined to be − 80/+ 100 mesh size durian husk exposing to an hour of acid pretreatment, resulting in a maximum reducing sugar recovery of 37.29 and 24.32 g/L for acid and enzyme hydrolysate, respectively. Fermentability tests using Actinobacillus succinogenes 130Z for both acid and enzyme hydrolysates demonstrated succinic acid yields of 49% and 63% (g/g), respectively. A stoichiometry equation describing the formation of substrate and all products was established based on the results obtained from batch fermentation: C₆H₁₂O₆ + 0.377 C₅H₁₀O₅ + 0.130NH₃ + 0.238CO₂ → 0.864 C₄H₆O₄ + 0.224 C₂H₄O₂ + 0.134CH₂O₂ + 0.292CH₂.₀₉₆O₀.₁₁₁N₀.₆₅₈ + 0.231 H₂O. This equation serves as a useful reference for future investigations into succinic acid production reactions. The cost-effectiveness of succinic acid production and its environmental performance were evaluated to highlight the potential of durian husk as feedstock. This study presents the first report on the utilization of durian husk as an alternative and sustainable feedstock for the production of bio-based succinic acid.