Biotechnological applications of extremophiles for biofuel production, bioremediation, and crop improvement

This project is focused on using extremophiles for biotechnical applications for improved biofuel production, bioremediation and crop improvement. Extremophiles are microorganisms that are capable of thriving in diverse extreme environmental conditions (i.e. high or low temperatures, high salinity, acidic or alkaline environments) and as a result these microbes have genes/proteins which can have attributes that are valuable to the development of novel biotechnological applications. Currently there are biologically imposed limitations to plant metabolism that constrain plant productivity, and thereby the amount of biofuel that can be generated from these plants. Several of the goals of this research (Objectives 1, 2, and 5) are targeted at improving plant productivity using select extremophile genes. Specifically, we are addressing the limitations of plant-based carbon fixation by designing a new carbon fixation cycle that can be used in plants in conjunction with the traditional Calvin-Benson cycle to convert atmospheric carbon dioxide to plant biomass and biofuel precursor molecules (Objective 1). In addition, extremophile genes are being used to enhance carbon dioxide uptake and nutrient recycle in algal biofuel systems (Objective 2). We are also introducing an antioxidant gene coding for superoxide reductase (SOR) into plants to improve the ability of plants to cope with environmental stresses such as temperature, drought, metal, radiation and pathogen stresses (Objective 5). Biofuels can also be generated from conversion of waste gas streams (CO and CO2 containing synthesis gas that can be produced from gasification of waste agriculture biomass) using microbial catalysts. We have developed a synthesis gas fermentation platform employing a modified strain of clostridium ljungdahlii and are using gene expression data and fermentation profiles to further improve this system (Objective 3). Much progress has also been made in recent years to use microbial catalysis to aid in critical efforts of biodecontamination of toxic substances in the environment. In particular recent research has demonstrated the great potential for using enzymes from extremophiles to provide efficient biocatalysis under a variety of potentially harsh process conditions. Continued research is required to identify and characterize suitable extremophile enzymes in order to develop robust microbial catalysis processes that would otherwise be impossible using standard enzyme systems or chemical methods. In particular, we are investigating the use of a proline dipeptidase enzyme called prolidase from the high temperature organism Pyrococcus furiosus to degrade toxic organophosphate compounds found in some nerve agents such as soman and sarin and in some pesticides (Objective 4). We have bioengineered highly active recombinant versions of the Pyrococcus prolidase enzymes that are active over a broad range of temperatures and are evaluating their ability to degrade nerve agent and pesticide analogs.