Rice: Unconventional Wisdom
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Metabolic Engineering and Synthetic & Systems Biology Laboratory

Ashutosh Gupta


Yandi Dharmadi

Education

B.S., Chemical Engineering, Indian Institute of Technology, Kanpur, India, 2001
Ph.D., Chemical Engineering, Rice University, 2007 (expected)


Project Description

Anaerobic fermentation of glycerol by E coli: a proteomics study
The large surplus of glycerol generated as inevitable by-product of biodiesel fuel production offers the opportunity to use this compound to produce reduced chemicals and fuels via fermentation. Realizing this potential would require the anaerobic fermentation of glycerol in the absence of external electron acceptors, a metabolic process that is restricted to small group of microorganisms. E. coli, considered the workhorse of modern biotechnology, is thought to metabolize glycerol only via respiration. However, we have found out that E. coli can indeed ferment glycerol, when grown under appropriate conditions. This discovery called for the investigation of the pathways that mediate the anaerobic fermentation of glycerol by E. coli cells. Although there is some knowledge available about glycerol metabolism in E. coli, a lot is still unknown. Respiratory metabolism of glycerol in E. coli is mediated by enzymes glycerol kinase and glycerol 3 phosphate dehydrogenase. In these steps glycerol is converted to dihydroxy acetone phosphate, which in turn can be converted to methylglyoxal, a toxic electrophile. Methylglyoxal detoxification occurs via its conversion to D-lactate, acetol and 1,2 propanediol. Production and consumption of redox equivalents plays an important role in this conversion process.  In this study, we will try to elucidate the metabolic pathways involved in anaerobic fermentation of glycerol by E. coli through characterization of mutant and recombinant strains by extensive fermentation profiling under different culture conditions. Some of these strains, showing significant differences in glycerol fermentation, will also be evaluated by two dimensional electrophoresis technology to elucidate the metabolic pathways involved under those conditions


Contact Information

C124 Abercombie
Rice University
Houston, TX, 77005
Phone (713) 348-2933
agupta@rice.edu