Tracing metabolism from lignocellulosic biomass and gaseous substrates to products with stable-isotopes

Engineered microbes offer a practical and sustainable alternative to traditional industrial approaches. To increase the economic feasibility of biological processes, microbial isolates are engineered to take up inexpensive feedstocks (including lignocellulosic biomass, syngas, methane, and carbon dioxide), and convert them into substrates of central metabolism and further into value-added products. To trace the metabolism of these feedstocks into products, isotopic tracers are applied together with isotopomer analysis techniques such as 13 C-metabolic flux analysis to provide a detailed picture of pathway utilization. Flux data is then integrated with kinetic models and constraint-based approaches to identify metabolic bottlenecks, propose novel metabolic engineering strategies, and improve process performance.