S89 Microbial metabolism of levulinic acid in P. putida and E. coli
Tuesday, July 26, 2016: 10:30 AM
Grand Couteau, 5th Fl (Sheraton New Orleans)
J. Rand* and D. Agnew, University of Wisconsin-Madison, Madison, WI; J. Thiede, University of Minnesota, Minneapolis, MN; B. Pfleger, University of Wisconsin - Madison, Madison, WI
Non-enzymatic sugar production is a promising alternative for second-generation biofuel production over traditional enzymatic hydrolysis due to its potential for lower cost and better scalability.  Recently, it has been shown that biomass can be efficiently converted into a simple 5 carbon molecule, levulinic acid (LA).  A limited number of microbes possess the capability to consume  this molecule and the enzymes responsible have not been elucidated.  In this work, we have isolated an enzymatic operon that is capable of metabolizing LA to central metabolites (acetyl-CoA and propionyl-CoA).  The laboratory microbe, Pseudomonas putida can readily consume LA as a sole carbon source.  Transposon studies in P. putida identified an operon involved in the LA metabolic pathway and through knockout and complementation studies we have confirmed the involvement of the operon in LA catabolism.   We have also engineered various mutant E. coli strains for the utilization of LA as a carbon source, which has allowed us to isolate key mutations between two industrial relevant E. coli strains: MG1655 and LS5218 .  This research will allow microbial upgrading of a more cost effective biomass hydrolysis to a variety of fuels and chemicals in a potentially economically viable manner.