Degree Type

Thesis

Date of Award

2008

Degree Name

Master of Science

Department

Chemical and Biological Engineering

First Advisor

Jacqueline V. Shanks

Second Advisor

Julie A. Dickerson

Third Advisor

Monica H. Lamm

Abstract

In recent years, metabolic flux analysis (MFA) has become an important tool in metabolic engineering. The MFA involves the quantification of intracellular metabolic fluxes in a microorganism. The result of MFA is a metabolic flux map that allows the systematic study of cellular responses to genetic and environmental perturbations. Carbon isotope labeling based MFA, with analysis by NMR or GC/MS, have gained wide use in the metabolic engineering community for estimating metabolic fluxes in central carbon metabolism. We are using MFA as a tool to engineer Escherichia coli sugar utilization regulatory (SURS) for the efficient consumption of sugar mixture.;E. coli SURS controls the utilization of different sugars as well as many other cellular functions. The SURS consist of the phosphoenolpyruvate (PEP)-dependent carbohydrate phosphotransferase system (PTS) and by several global regulators including CRP (cAMP receptor protein), Mlc (controlling several glycolytic, gluconeogenic and glucose-related genes), and Cra (catabolite repressor/activator protein). The tight control of sugar utilization in E. coli by SURS results in the sequential consumption of other sugars in the presence of glucose, which results in low yields and productivities of the desired product.;We have constructed E. coli strain devoid of gene encoding ptsG. The ptsG is involved in the transport of glucose and plays an important role in carbon catabolite repression. The ptsG-strain didn't show diauxic growth and consumed glucose and xylose simultaneously. It grew slower than wild type grown on glucose and had a long lag time. Our flux analysis revealed that slow growth of ptsG mutant is due less efficient transport of xylose and glucose in the mutant which results in less available ATP for biomass synthesis.

DOI

https://doi.org/10.31274/rtd-180813-16544

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Madhuresh Kumar Choudhary

Language

en

Proquest ID

AAI1453128

OCLC Number

244436448

ISBN

9780549541981

File Format

application/pdf

File Size

130 pages

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