Riboflavin synthesis from gaseous nitrogen and carbon dioxide by a hybrid inorganic-biological system

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 119; no. 37; p. e2210538119
• Main Authors: Sherbo, Rebecca S, Silver, Pamela A, Nocera, Daniel G
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 13.09.2022
• Subjects: Ammonia; Autotrophic microorganisms; Bacteria; Carbon dioxide; Carbon Dioxide - metabolism; Carbon sources; Energy efficiency; Food; Gas mixtures; Genetic engineering; Hybrid systems; Microorganisms; Nitrogen; Nitrogen - metabolism; Nitrogen fixation; Nitrogenation; Nutrient sources; Nutrients; Oxidation; Physical Sciences; Plasmids; Riboflavin; Riboflavin - biosynthesis; Sugar; Vitamin B; Water - chemistry; Water splitting; Xanthobacter - growth & development; Xanthobacter - metabolism; Xanthobacter; nitrogen fixation; sustainability; vitamin production; carbon fixation
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2210538119

Microbes can provide a more sustainable and energy-efficient method of food and nutrient production compared to plant and animal sources, but energy-intensive carbon (e.g., sugars) and nitrogen (e.g., ammonia) inputs are required. Gas-fixing microorganisms that can grow on H from renewable water splitting and gaseous CO and N offer a renewable path to overcoming these limitations but confront challenges owing to the scarcity of genetic engineering in such organisms. Here, we demonstrate that the hydrogen-oxidizing carbon- and nitrogen-fixing microorganism grown on a CO /N /H gas mixture can overproduce the vitamin riboflavin (vitamin B ). We identify plasmids and promoters for use in this bacterium and employ a constitutive promoter to overexpress riboflavin pathway enzymes. Riboflavin production is quantified at 15 times that of the wild-type organism. We demonstrate that riboflavin overproduction is maintained when the bacterium is grown under hybrid inorganic-biological conditions, in which H from water splitting, along with CO and N , is fed to the bacterium, establishing the viability of the approach to sustainably produce food and nutrients.