Metabolic Engineering and Transhydrogenase Effects on NADPH Availability in Escherichia coli

The ultimate goal in the field of metabolic engineering is improving cellular processes in a rational manner using engineering design principles and molecular biology techniques. The syntheses of several industrially useful compounds are cofactor-dependent. The reducing equivalent NADPH is required in several enzymatic reactions leading up to the synthesis of high-value compounds like polymers, chiral alcohols, and antibiotics. However, it’s a highly costly compound with limited intracellular availability. This study focuses on the genetic manipulation of a whole-cell system using the two transhydrogenase isoforms pntAB and udhA. Two model systems are used: 1) the production of (S)-2-chloropropionate and 2) the production of poly(3-hydroxybutyrate). Results suggest that the presence of udhA increases product yield and NADPH availability while the presence of pntAB has the opposite effect. A maximum product yield of 1.4 mole-product/mole-glucose was achieved aerobically in a pntAB-deletion strain with udhA overexpression, a 150% improvement over the wild-type control strain.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Engineering

Grantor

Rice University

Year dc:date.issued

2012

Author dc:creator

• Jan, Joanna

Advisor dc:contributor.advisor

• San, Ka-Yiu

Committee members dc:contributor.committeemember

• Bennett, George N.
• Gonzalez, Ramon

• Metabolic engineering
• Escherichia coli
• Nadph
• Cofactor
• Transhydrogenase

Statement dc:rights

• Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1911/64664

OAI identifier oai:identifier

oai:repository.rice.edu:1911/64664