SGER: Genetic Engineering of Archaeoglobus Fulgidus
The carbon source requirements of all known methanogens are limited to simple C1 and C2 compounds such as CO2, methanol, formate, and acetate despite the fact that methanogenesis from higher molecular weight carbon sources would be sufficiently exergonic for growth. Current anaerobic digestion processes for methane production involve three basic steps: solubilization, acidogenesis, and methanogenesis. These processes are carried out by different microbial consortia with different pH optima. The goal of this project is to engineer a microbe capable of methanogenesis from complex substrates. This will improve the rate and efficiency of anaerobic digestion processes for methane production. The organism, Archaeoglobus fulgidus, is an extremely thermophilic (83 degrees C) sulfate-reducing Archaeon that grows on a broad range of carbon sources including peptone, starch, and gelatin. A. fulgidus has been referred to as "the evolutionary missing link" between the methanogens and the sulfate metabolizers as it utilizes all but the final enzymes involved in methanogenesis. In this exploratory project, both mutation/selection strategies and gene transfer techniques are being used to create a broad-substrate-range methanogen from A. fulgidus. Success in genetically engineering Archaeolglobus should lead to a major improvement in the rate and efficiency of production of methane, a desirable energy source.