Fungal Production of Itaconic Acid From Palm Kernel Cake in Submerged Fermentation By Aspergillus niger and Aspergillus terreus

Abstract

Agricultural wastes often accumulate in the environment resulting in pollution and loss of biomass which could serve as substrate for production of other value-added products. In this study, two fungi; Aspergillus niger (ATCC 16404) and Aspergillus terreus (ATCC 20542) were used to ferment palm kernel cake (PKC); an agro-industrial waste to produce itaconic acid (IA). The proximate composition was determined. PKC was pre-treated with alkali and steam and fermented in mineral salt medium with inocula of A. niger and A. terreus. Fermentation parameters were pH 5.4; 10% substrate concentration; 10% inocula at 29±1 °C for 5 days. Fermentation was optimized by varying fermentation parameters. Proximate analysis of PKC showed carbohydrates (45.5%), crude protein (4.50%) and lipids (9.21%).  IA yield of 47.0 g/L and 42.27 g/L was produced by A. niger and A. terreus from PKC respectively. Optimization produced higher IA yields of 100.33 g/L and 105.00 g/L by A. niger and A. terreus respectively at pH 4.0; substrate concentration of 10g; inocula size of 10% at 29±1°C on Day 5 of the fermentation representing 53.15% (A. niger) and 59.74% (A. terreus) increase over the pre-optimization levels. The results support the potential use of PKC for the industrial production of IA.