Nutrient-Dependent Metabolism and Cycling of Carbon Mixtures in Pseudomonas Species

Abstract: Bacterial processing of organic matter, both in natural carbon cycling and in engineered bioconversion, represents an important component in environmental sustainability. Cellular metabolism has the potential to recycle organic matter to yield biofuel products, bioplastic monomers, antibiotic molecules, and other valuable products. Of special interest is the cellular metabolism of soil Pseudomonas species, which include plant growth-promoting bacteria and bioplastic producers, that thrive in diverse nutritional environments due to their extensive metabolic capabilities. These bacterial species thus represent model candidates for understanding carbon utilization and exploiting new avenues for biotechnology. Using mass spectrometry-based metabolomics combined with stable isotope labeling and flux analysis, my research group has gained insights on the underlying metabolism that determines selective carbon utilization towards biosynthetic pathways in Pseudomonas putida, P. protegens, and P. fluorescens. This talk will focus on our elucidation of the metabolic network for simultaneous processing of aromatic and carbohydrate carbons. To scavenge iron from soil minerals, the cells rewire the metabolic network and promote the biosynthesis of structurally-diverse specialized peptides. Our data shed light on how constitutive reprogramming of cellular carbon metabolism couples metal availability with carbon recycling in Pseudomonas species. These findings are important in predicting the metabolic controls of natural carbon cycling and exploring new biotechnological platforms for bioconversion.

Bio: Dr Aristilde's interest in environmental issues stemmed from her experiences growing up in Haiti. After emigrating to the States, she went to Cornell University to obtain a B.S. in Science of Earth Systems and then to the University of California-Berkeley for her M.S. in Environmental Engineering and Ph.D. in Molecular Toxicology. After Berkeley, she went to Grenoble (France) as an American Fulbright Scholar to advance her knowledge of surface spectroscopic techniques to study mineral trapping of organic matter. Prior to starting her faculty position as an Assistant Professor at Cornell University, she spent three years as a NSF Postdoctoral Fellow at Princeton University where she studied molecular biology tools to address research questions at the interface of environmental chemistry and environmental biological processes.