The development of microbial metabolic engineering has largely been based on a limited number of recombinant hosts (e.g., Escherichia coli, Saccharomyces cerevisiae) because of the substantial knowledge of the physiology of these microorganisms and availability of associated molecular genetic tools. However, as metabolic engineering is directed at more and more innovative bioprocessing objectives, there is a pressing need to expand the range of potential microbial hosts. Because extremophiles are already endowed with properties that are amenable to the harsh conditions characteristic of industrial processes, it makes sense to develop metabolic engineering capabilities for this group of microorganisms. This direction would have been implausible until very recently, but newly developed molecular genetic tools and genomics studies have opened up the prospects for metabolic engineering of extremophiles. As such, this proposed project will demonstrate the efficacy of metabolically engineering the hyperthermophilic archaeon, Pyrococcus furiosus, which grows optimally at 100°C. To demonstrate that this microorganism can, indeed, be metabolically engineered, the work will build upon recent success in temperature-dependent biochemical processing and will now produce a specialty chemical, succinate, from cellobiose and maltose. Genes encoding transporters and metabolic enzymes identified from less thermophilic organisms with optimum temperature values near 70°C will be imported into a recombinant P. furiosus strain. Novel approaches for gene regulation and product formation that strategically exploit hyperthermophilicity will be utilized to optimize yields and efficiencies for bioproduct formation near 70°C. Providing a paradigm for metabolically engineering a hyperthermophilic host to produce a non-physiological product will pave the way for thermally-based, bioprocessing opportunities.
Broader impacts will result from the interdisciplinary training of students in molecular biochemistry, functional genomics and biomolecular engineering for studying extremophile biology and biotechnology. Two undergraduate researchers will be recruited during each fall semester and be supported subsequently for a summer research experience in the PI's laboratories (one biochemist at UGA and one chemical engineer at NCSU). These students will spend two weeks during the summer at the other collaborating lab to foster interdisciplinary training. All students on this and related projects at NCSU and UGA will participate in an annual extended 'Hyperthermophile Group Meeting' during the summer to be hosted at NSCU and UGA on an alternating basis. This will foster interdisciplinary training and collegiality, as well as provide a mechanism for exchange of research ideas and methodologies.
