Geobacter strains that use alternate organic compounds, methods of making, and methods of use thereof
Inventors
Lovley, Derek R. • Summers, Zarath Morgan • Haveman, Shelley Annette • Izallalen, Mounir
Assignees
Publication Number
US-9273280-B2
Publication Date
2016-03-01
Expiration Date
2029-08-08
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
In preferred embodiments, the present invention provides new isolated strains of a Geobacter species that are capable of using a carbon source that is selected from C3 to C12 organic compounds selected from pyruvate or metabolic precursors of pyruvate as an electron donor in metabolism and in subsequent energy production. The wild type strain of the microorganisms has been shown to be unable to use these C3 to C12 organic compounds as electron donors. The inventive strains of microorganisms are useful for improving bioremediation applications, including in situ bioremediation (including uranium bioremediation and halogenated solvent bioremediation), microbial fuel cells, power generation from small and large-scale waste facilities (e.g., biomass waste from dairy, agriculture, food processing, brewery, or vintner industries, etc.) using microbial fuel cells, and other applications of microbial fuel cells, including, but not limited to, improved electrical power supplies for environmental sensors, electronic devices, and electric vehicles.
Core Innovation
The present invention provides new isolated strains of Geobacter species capable of using carbon sources selected from C3 to C12 organic compounds, including pyruvate and metabolic precursors of pyruvate, as electron donors for metabolism and energy production. Wild type strains of these microorganisms are unable to use such compounds as electron donors. The inventive strains comprise a functional mutation in a gene encoding a repressor of succinyl-CoA synthetase activity, enabling activation of this enzyme and thereby expanding substrate utilization.
This invention addresses the limitation in the metabolic range of wild-type Geobacter sulfurreducens strains, which hinders their ability to oxidize compounds beyond simple molecules like acetate, hydrogen, and some aromatics. This limitation restricts applications such as bioremediation and microbial fuel cell power production to narrow substrates. The inventive strains overcome these challenges by acquiring mutations—specifically a single nucleotide polymorphism in the gene encoding the transcriptional repressor GSU0514—that derepress succinyl-CoA synthetase, allowing utilization of a broader range of organic compounds including lactate, glucose, glycerol, and xylose.
The inventive strains improve efficiency in bioremediation applications by enabling use of electron donors not metabolizable by wild-type strains, including for uranium and halogenated solvent remediation. Additionally, these strains enhance electricity production in microbial fuel cells by oxidizing diverse, more energy-dense organic compounds derived from various waste sources. Methods of making these adapted strains involve serial culture transfers selecting for growth on alternative electron donors, and methods of use include deployment in fuel cells, waste facility power generation, and in situ environmental remediation.
Claims Coverage
The patent contains several independent claims covering methods of making adapted Geobacter strains, isolated strains with specific mutations, and methods of using these strains in microbial fuel cells and bioremediation.
Method of making adapted Geobacter strains
A serial culture adaptation method starting with parent Geobacter sulfurreducens strain ATCC-51573 involving sequential transfers to growth media where an alternative organic compound replaces the preferred electron donor. Growth is monitored through exponential phases with transfers repeated under defined performance criteria until an adapted strain capable of efficiently utilizing the alternative donor is isolated.
Adapted Geobacter strains with mutation in transcriptional repressor
Isolated Geobacter sulfurreducens strains with a single nucleotide polymorphism (G to A at position 548250) in GSU0514 gene encoding a transcriptional repressor of succinyl-CoA synthetase, resulting in an E to K amino acid change and activation of succinyl-CoA synthetase enzyme enabling effective utilization of pyruvate and C3 to C12 metabolic precursors as electron donors.
Method of improving electricity production using adapted Geobacter strains
Providing a microbial fuel cell comprising an anode, cathode, conductive connection, and an isolated anodophilic Geobacter strain capable of utilizing pyruvate or C3 to C12 metabolic precursors as electron donors. The oxidation of these compounds by the strain results in improved electricity generation to power devices such as environmental sensors, electronics, or electric vehicles.
Method of generating electrical power at waste facilities using adapted strains
Providing waste compartments with anode and cathode connections and inoculating with adapted Geobacter strains capable of utilizing pyruvate or C3 to C12 metabolic precursors in biomass waste from industries (e.g., dairy, agriculture, brewery). Oxidation of these compounds by the strains generates electrical power at waste facilities.
Method of improving in situ bioremediation using adapted Geobacter strains
Providing electrodes in contaminated soil or groundwater, adding organic compounds like lactate and an adapted Geobacter strain capable of effective utilization of these compounds as electron donors, resulting in enhanced reduction of contaminants such as halogenated solvents or toxic metals including uranium via electron transfer that promotes bioremediation.
The claims cover the invention's core concept of generating and using Geobacter strains with mutations in a transcriptional repressor gene enabling the utilization of a broader range of electron donors, including methods of making such strains and using them for enhanced electricity generation and bioremediation.
Stated Advantages
Broader substrate utilization by Geobacter strains enables oxidation of more energy-dense compounds than wild-type strains.
Improved growth rates and efficient utilization of alternative electron donors such as lactate, glucose, glycerol, and xylose.
Enhanced electricity production in microbial fuel cells using adapted strains oxidizing diverse waste-derived substrates.
More effective and sustainable in situ bioremediation of contaminated sites including uranium and halogenated solvents by utilizing efficient electron donors.
Use of less expensive and more readily available organic compounds as electron donors for industrial and environmental applications.
Genetic characterization confirming the functional linkage between mutations in the transcriptional repressor and expanded metabolic capabilities facilitates targeted strain development.
Documented Applications
Improving bioremediation of contaminated sites including uranium bioremediation and halogenated solvent bioremediation by using adapted Geobacter strains capable of utilizing lactate and related compounds as electron donors.
Use of adapted Geobacter strains in microbial fuel cells for power generation from small and large-scale waste facilities such as biomass waste from dairy, agriculture, food processing, brewery, and vintner industries.
Powering environmental sensors, electronic devices, and electric vehicles through improved microbial fuel cells employing the adapted strains with broader substrate utilization.
Generating electrical power at waste facilities by combining adapted Geobacter strains with waste products containing pyruvate or metabolic precursors as fuel sources.
Interested in licensing this patent?