Fumaric Acid Production from Crop Residues
Fumaric acid is a four-carbon unsaturated dicarboxylic acid that is widely used in food, chemical, and pharmaceutical industries. In the last two decades, because of its nontoxic nature, fumaric acid has found two new exciting applications in medicine and greenhouse gas mitigation. As a medicine, fumaric acid can treat the skin disease psoriasis. For greenhouse gas mitigation, recent studies show that up to 70% of CH4 emission from cattle can be reduced by feeding them with a fumaric acid supplemented diet. This finding is of extreme significance as the world is striving to reduce the total emission of CH4 (a notorious greenhouse gas), of which farm animals (mainly cattle) account for 14%. However, these benefits of fumaric acid in improving human health and tempering climate change can only be reaped if fumaric acid can be produced in a sustainable manner. Fumaric acid is currently produced chemically from maleic anhydride (a product from petroleum resources). With depleting fossil fuel reserves and rising crude price, continuing to rely on petrochemicals to produce fumaric acid is neither economically nor environmentally sustainable. Thus, use of renewable resources for such purpose will become the only alternative. Among the renewable resources, lignocellulosic biomass is considered to be the most promising option due to large volumes generated from crop production that can be hydrolyzed to oligosaccharide and further converted to value-added products by microbes. In Arkansas, the major waste lignocellulosic biomass is rice straw together with corn production residues, which is an excellent renewable feedstock for sustainably producing fumaric acid if effective technologies are developed.