Microbial Conversion of Greenhouse Gases into Fermentation-Ready Sugars

San Diego State University Foundation, San Diego CA

Investigators

Abstract

1605031 Kalyuzhnaya, Marina Human-related activities, such as fossil fuel production, agriculture, landfill use, and municipal wastewater are major contributors to global methane emission. Widespread and steady growth of these man-made emissions make methane not only a major contributor to climate change but also the primary target for near-term climate regulation. In this project a new dry fermentation process for biological methane utilization will be developed. This process is based on the unique ability of salt-loving, methane-consuming bacteria to not only stay active in an immobilized state without water supplementation but also to accumulate sugar in response to low water availability. Dry fermentation merges the full potential of biological systems with technology development to address affordable methane mitigation. Proposed is the development of an array of micro-fibers with active methane-consuming cells engineered to convert methane into extractable sucrose. The specific aims of the proposal include (i) the rational modification of microbial catalysts to enhance sucrose production capabilities by reducing ectoine, glycogen and (exo)polysaccharides synthesis; (ii) the rational modification of the microbial catalyst to reduce oxygen consumption, including overexpression of bacteriohemerythrin to improve oxygen consumption, and development of strain-specific vectors for rapid integration of large DNA fragments; (iii) the lab-scale design and validation of the developed Dry Fermentation Module by investigating water-stress impacts on methane consumption and sucrose accumulation rates in methanotrophic 'living' micro-fibers. The proposed modules could represent a transformative solution for methane conversion into useful products. The module could be developed further into air-purifying cartridges that could be implemented at any hot-spot of methane emission, as a sustainable alternative to gas flare. The metagenomic libraries constructed in this project represent a novel approach for natural products discovery with a non-traditional host. The project will actively involve graduate, undergraduate, and high school students and encourage cross-disciplinary collaboration and establish partnerships with industry. This award by the Biotechnology and Biochemical Engineering Program of the CBET Division is co-funded by the Systems and Synthetic Biology Program of the Division of Molecular and Cellular Biosciences.