Harnessing agro-industrial waste: Enzyme-driven biosynthesis in Itaconic acid production☆

Itaconic acid (IA) is a highly soluble and stable bio-based chemical with diverse industrial applications, particularly in sustainable material production. Despite the growing demand for bio-based IA, efficient and sustainable production methods remain a challenge, particularly in optimizing fungal fermentation and byproduct utilization. This study explores the synergistic use of solid-state fermentation utilizing Aspergillus awamori for enzyme production and hydrolysis, combined with submerged fermentation to optimize IA bioproduction from wheat bran by-products. The optimal levels of enzyme production observed on the third day were closely related to moisture's vital role in synthesis dynamics, influencing glucose concentration and enzyme activities. The activities of glucoamylase, cellulase, and endoglucanase exceeded 50 U/g, 55 FPU/g, and 15 U/g, respectively. Subsequent IA bioproduction using A. terreus was optimized under various initial pH levels, with pH 4 and 5 demonstrating superior IA yields of 8.082 +/- 0.19 g/L and 10.782 +/- 0.98 g/L, respectively. Scaling up challenges highlight the need for a 30 % enzyme extract in wheat bran hydrolysis, with economic favorability and achieving a 52 % IA conversion efficiency from citric acid. This approach underscores sustainable IA production from agro-industrial by-products, aiding the circular economy and bio-based processes.