The syngas platform for conversion of lignocellulosic biomass to liquid biofuels involves a thermochemical conversion step to produce syngas (H2 + CO) followed by biological conversion of syngas to liquid biofuels. Combining the two steps overcomes the limitations of sequential conversion steps for producing second-generation biofuels, but only when the syngas bioreactor allows high rates of gas delivery to the homoacetogenic bacteria responsible for syngas conversion. The PIs propose a collaborative project aiming to adapt the hollow-fiber membrane biofilm reactor (MBfR), now used for water treatment, to deliver the low-solubility gases directly to a biofilm that grows on the outer surface of a hollow-fiber membrane and utilizes the gas as a substrate. The membrane-based biofilm avoids direct gas-liquid mass transfer, which normally slows the rate of H2 and CO delivery. The over-arching goal is to adapt the MBfR for the production of valuable chemicals from syngas.
The proposed collaborative project aims to develop the scientific and engineering foundations for a new environmental-biotechnology platform that allows rapid and cost-effective conversion of syngas to valuable organic products. The proposed research will be focused on developing a fundamental mechanistic understanding of the novel material properties of asymmetric membranes useful in the MBfR, the physiology of homoacetogens that work well in a biofilm, and the interactions of biokinetic, ecological, and mass-transfer processes in biofilms fed with H2 and CO. The proposed research, if successful, will contribute to the foundation of a new environmental biotechnology platform for the production of valuable products from syngas (H2 and CO). The project will involve an experimental investigation focused on the development of membranes and the selection and characterization of suitable microorganisms (homoacetogens). It will also involve the development of a theoretical model, based on the experimental data, to describe and optimize the performance of biofilm reactors. The project will include a STEM education and workforce development effort by involving under-represented community-college students in research. An outreach effort to high school students will be focused on sustainability and green chemistry demonstrations in high school science laboratories and on hosting teachers and students for summer research internships.
National Science Foundation, Division of Chemical, Bioengineering, Environmental, and Transport Systems