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Appl Environ Microbiol, January 1998, p. 98-105, Vol. 64, No. 1
Department of Chemical Engineering,
University of Wisconsin
Received 3 March 1997/Accepted 5 September 1997
The genes for the production of 1,3-propanediol (1,3-PD) in
Klebsiella pneumoniae, dhaB, which encodes
glycerol dehydratase, and dhaT, which encodes 1,3-PD
oxidoreductase, are naturally under the control of two different
promoters and are transcribed in different directions. These genes were
reconfigured into an operon containing dhaB followed by
dhaT under the control of a single promoter. The operon
contains unique restriction sites to facilitate replacement of the
promoter and other modifications. In a fed-batch cofermentation of
glycerol and glucose, Escherichia coli containing the
operon consumed 9.3 g of glycerol per liter and produced 6.3 g of 1,3-PD per liter. The fermentation had two distinct phases. In the
first phase, significant cell growth occurred and the products were
mainly 1,3-PD and acetate. In the second phase, very little growth
occurred and the main products were 1,3-PD and pyruvate. The first
enzyme in the 1,3-PD pathway, glycerol dehydratase, requires coenzyme
B12, which must be provided in E. coli
fermentations. However, the amount of coenzyme B12 needed
was quite small, with 10 nM sufficient for good 1,3-PD production in
batch cofermentations. 1,3-PD is a useful intermediate in the
production of polyesters. The 1,3-PD operon was designed so that it can
be readily modified for expression in other prokaryotic hosts;
therefore, it is useful for metabolic engineering of 1,3-PD pathways
from glycerol and other substrates such as glucose.
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Construction and Characterization of a
1,3-Propanediol Operon
and
Madison, Madison, Wisconsin 53706
*
Corresponding author. Mailing address: Department of
Chemical Engineering, 1415 Engineering Dr., University of
Wisconsin
Madison, Madison, WI 53706-1691. Phone: (608) 262-8931. Fax:
(608) 262-5434. E-mail: cameron{at}engr.wisc.edu.
Present address: Department of Chemical Engineering, University of
Rochester, Rochester, NY 14627-0166.
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