Dr. Lisa Stein > Associate Professor
Contact
Room: M 528, Biological Sciences
Phone: (780) 492-4782
Fax: (780) 492-9234
Email: lisa.stein@ualberta.ca
Academic Training
PhD: Oregon State University
BA (Magna cum laude): University of Colorado
Research Interests
- Physiology, genomics, and ecology of nitrification and denitrification.
- Influence of microbial metabolism on greenhouse gas production.
- Nitrogen and methane remediation in industrial processes.
Work in our laboratory focuses on the numerous and diverse pathways of inorganic nitrogen metabolism and assimilation in prokaryotes. Using the tools of comparative genomics, molecular biology, physiology, and biochemistry we study how microorganisms process nitrogen at the molecular, whole-cell, and ecosystem levels. Our goals are to track the evolution of nitrogen metabolism and to predict how and when deleterious nitrogen oxide products are released to the environment. The greenhouse gas nitrous oxide, the ozone depleting nitric oxide, and the groundwater polluting nitrate are the most significant of the nitrogen oxide pollutants created and released by microbial nitrogen metabolism.
Current Projects
MOB Squad: a) Methane-oxidizing bacteria produce a sizeable amount of nitrous oxide when exposed to non-limiting concentrations of inorganic nitrogen and lower than atmospheric oxygen levels. Through the collaborative Organization for Methanotroph Genome Analysis (OMeGA), we have gained access to tens of genome sequences of methanotrophic bacteria, allowing us to test and map functional pathways responsible for nitrous oxide production. The capacity for any given methanotroph to resist and metabolize excess nitrogen is a strong indicator for its survival in N-impacted ecosystems such as agricultural soils, thawing permafrost, compost, or landfills. Methanotrophic species that thrive in N-impacted ecosystems likely contribute significantly to the global greenhouse gas budget.
b) Ammonia-oxidizing bacteria possess similar nitrous oxide producing pathways to methanotrophs, but differ in that nitrous oxide production is intrinsic to their metabolism. We are continuing a decades-long study of nitrous oxide generating pathways in ammonia-oxidizers to understand their evolution, variability, and necessity to the nitrification process. Assisting this effort is the continued generation and analysis of ammonia oxidizer genome sequences in collaboration with an international team of scientists.
c) The City of Edmonton is testing the utility of biofilters to remove excess biogas (methane) from an anaerobic digestor for certain types of municipal waste. The methanotrophs in the biofilter remove the methane a reasonable rates so long as the temperature and moisture regimes remain favorable. We are working with the City to monitor methanotrophic populations in biofilters and test ways to maximize their activity.
Agent Green: Like the methanotrophs, the fungus Fusarium oxysporum produces a sizeable amount of nitrous oxide under hypoxic conditions and in the presence of formate and nitrate. F. oxysporum is a well known plant pathogen and is widely distributed in soils. In collaboration with Dr. Steven Siciliano at the Univ. of Saskatchewan, we are comparing the ability of several F. oxysporum and other fungal strains to produce nitrous oxide alone and in partnership with various bacterial species. We are also attempting to generate molecular marker sequences that can be used to assess the relative contribution of fungi to nitrous oxide production in the environment, with particular emphasis on Arctic and agricultural soils.
Aquaponics: In collaboration with Dr. Andrew Keddie at the Univ. of Alberta, we are studying the nitrogen cycling organisms in self-contained systems that grow both fish and plants.
Ice Diamond: We are working with Diavik Diamond Mines Inc. to maximize ammonium and nitrate removal from a tailings pond at near-freezing temperatures using molecular and traditional microbiological approaches.
|
Last Modified:2011-05-30 |