Biofiltration Incorporating Gene Silencing Technology for the Production of Methanol From Methane Containing Waste GasesEPA Grant Number: FP917175
Title: Biofiltration Incorporating Gene Silencing Technology for the Production of Methanol From Methane Containing Waste Gases
Investigators: Strickland, Matthew Robert
Institution: Duke University
EPA Project Officer: Zambrana, Jose
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Science & Technology for Sustainability: Energy
The objective of this research is to develop a new method by which methanol can be generated biologically from methane. Specifically, by using gene silencing techniques, the metabolism of the methanotroph can be altered allowing for control of critical gene expression. Some questions that remain to be answered include: How will antisense silencing be deployed? What is the effect of interrupting the metabolism in such a way? Is this method sustainable? Is this method scaleable for application in industry? Could this method be applied to other areas of interest, such as the production of noxious gasses (hydrogen sulfide) by other microorganisms?
At many landfills or other methane generating facilities, biogas that is not economically upgradeable for use as a fuel source is often vented to the atmosphere or flared. The goal of this research is to develop a novel method by which methanotrophic bacteria, microorganisms that consume methane as an energy source and carbon source, may be engineered to instead convert methane into methanol. The collected methanol may then be barreled and used as a fuel commodity.
How will antisense silencing be deployed? In order to produce the necessary antisense strands as depicted in the original fellowship proposal, a plasmid has been engineered that will produce said antisense strands. Trial studies will be conducted during the summer. What is the effect of interrupting the metabolism in such a way? Most importantly, the inhibition of the MDH gene will prevent the cell from producing new cell mass or from regenerating NADH. One solution is to supplement the cells with a different metabolite downstream from methanol (pyruvate). Another solution is to control silencing with a solid promoter on the plasmid. In that way, partial silencing can be achieved where cells still grow, but they still excrete methanol. Is this method sustainable? If the system can be optimized in such a way that no other compounds (such as pyruvate) must be added, yes, it is theoretically sustainable. Is this method scaleable for application in industry? Given the large scale production of methane at many mid- and large-scale landfills or composting facilities, which cannot economically upgrade their biogas for injection into the natural gas grid, this approach could be applicable for industry. Part of the research will include inoculation and operation within a laboratory scale biotrickling filter that is supplied with synthetic biogas (methane and CO2 supplemented with air). Could this method be applied to other areas of interest, such as the production of noxious gases (hydrogen sulfide) by other microorganisms? Yes, if this tool set is well developed, it could be applied to many biosystems where specific genes could enhance operations!
I expect the proposed and revised approach will work, as there are multiple examples of plasmid-based gene silencing systems in nature (HOK/SOK is a perfect example). The challenge will be in developing a strong plasmid for use in methanotrophs.
Potential to Further Environmental/Human Health Protection
Again, this technology could be applied to many systems where biological degradation is not favored due to the production of secondary noxious gases or other interfering compounds. In a sense, we will be able to create better, smarter microbes for closed-system bioremediation.