Itaconic Acid Production from Corn Stover Hydrolysate by Engineered Escherichia coli with the Weimberg Pathway and Carbon Flux Redirection

Abstract

To achieve itaconic acid production using non-food feedstocks, this study constructed an engineered Escherichia coli strain capable of efficiently synthesizing itaconic acid using corn stover hydrolysate as the carbon source. By heterologously expressing cis-aconitate decarboxylase, relieving carbon catabolite repression, eliminating by-product synthesis pathways, deleting isocitrate dehydrogenase, introducing the Weimberg pathway to reconstruct the α-ketoglutarate supply route, and incorporating a feedback-resistant citrate synthase from Corynebacterium glutamicum, the carbon flux was progressively optimized toward the directed synthesis of itaconic acid. Furthermore, this study employed a low-waste alkali pretreatment strategy to obtain corn stover cellulose hydrolysate, thereby reducing waste liquid discharge and minimizing the loss of cellulose and hemicellulose. Using the resulting non-detoxified hydrolysate as the substrate, the engineered strain BI18 achieved an itaconic acid titer of 57.1 g/L in fed-batch fermentation, with a total sugar conversion yield of 0.61 g/g. This production routeintegrating strain engineering, non-food feedstocks, and low-waste pretreatmentprovides a technical reference for itaconic acid biorefining from lignocellulosic biomass.