Today’s (chemical) industry is founded on fossil-based raw materials (i.e., coal, gas, and oil), despite their negative impacts on our all future, including global warming. A change from fossil to sustainable raw materials is required since the demand for food, energy, and chemicals will keep increasing for the next decades. Using renewable carbon sources (i.e., biomass, CO2, organic waste) will allow a future independent of fossil carbon.Ustilaginaceae, a family of smut fungi, displays a broad product spectrum featuring organic acids (e.g., itaconate, malate, succinate), polyols (e.g., erythritol, mannitol), and extracellular glycolipids (ustilagic acid, mannosylerythritol lipids). These molecules are considered value-added chemicals with potential applications in the pharmaceutical, food, and chemical industry. Importantly, in combination with feeding alternative C-sources as (co-)substrates (e.g., acetate, formate, glycerol, lignocellulose), these microorganisms offer excellent potential for reducing CO2 emissions and land use. Organic acids, such as itaconic acid, can function as sustainable alternatives to fossil-based chemicals, since their functional groups enable their use as building blocks. This work focused on bioprocess optimization and metabolic engineering strategies to establish a sustainable, industrially relevant Ustilaginaceae itaconate production host competitive to Aspergillus terreus. Concerning the bioprocess optimization aspect, acetate and formate were presented Investigating the biodiversity using 72 Ustilaginaceae, Ustilago maydis MB215 and Ustilago cynodontis NBRC 9758 were identified as potential production hosts using the displayed co-substrates. Metabolic engineering was performed using CRISPR/Cas9 genome editing and the FLP/FRT system with marker recycling. This way, a novel itaconate-producing chassis strain was designed characterized by a reduced by-product spectrum (ΔUA, ΔMEL) and the insertion of an overexpressed mttA gene of A. terreus. The wildtype and metabolically engineered strains of U. maydis and U. cynodontis were further optimized by applying the Design of Experiment (DoE) methodology. The established empirical models were used for predicting itaconate production (titer, yield), focusing on the glucose/co-substrate ratio. Acetate assimilation in U. maydis was investigated using off-gas analysis and a 13C-labeling approach. While acetate was not incorporated into itaconate when glucose was present, the induction of the glyoxylate shunt for increased acetate utilization seemed promissing. Extra electrons from formate were supplied from biphasic Ru-catalysed CO2 hydrogenation reactions without any purification, highlighting the many possibilities of chemo- and biocatalysis for carbon capture and utilization. Long-term itaconate production during the stationary phase (weeks rather than days) was achieved using an external ceramic membrane to avoid product inhibition. The here presented results contribute to the production of itaconate from sustainable carbon sources, with the overall goal of reducing land use and carbon footprints.