A review on microbial metabolic engineering for the improvement of itaconic acid production

Itaconic acid (IA), also known as methylene-butanedioic acid, is one of the top 12 platform chemicals in the world and demand for it is growing worldwide. The itaconic acid molecule contains one reactive double bond and two carboxyl groups, endowing it with chemical reactivity. It is widely used in fields such as light industry, agriculture, energy, and medical applications. The recent progress in understanding the biosynthesis, the regulation and the cellular transport of itaconic acid has facilitated the optimisation of existing processes as well as the construction of new microbial platforms. However, there is still need for further optimisation to increase the space-time yield, to achieve higher final concentrations and to use a broader range of low cost sustainable raw materials. In this review article, we have summarized the current status of itaconic acid production by natural microbial strains, recent advances in research on genetically engineered modified strains, and further analyzed the gene clusters associated with itaconic acid biosynthesis in Aspergillus terreus, Ustilago maydis, as well as similar genetic clusters identified in A. niger. Genetic engineering and process development need to apply intelligent screening platforms to obtain as much information as possible in small scale so as to provide more detailed basic information and newer improvement ideas for subsequent research.