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Regulation of 3-hydroxypropionaldehyde accumulation in Klebsiella pneumoniae by overexpression of dhaT and dhaD genes

Paper ID Volume ID Publish Year Pages File Format Full-Text
17692 42689 2009 5 PDF Available
Title
Regulation of 3-hydroxypropionaldehyde accumulation in Klebsiella pneumoniae by overexpression of dhaT and dhaD genes
Abstract

3-Hydroxypropionaldehyde (3-HPA), an important intermediary metabolite of 1,3-propanediol (PDO) production, would be toxic to the cell growth and led to the abnormal cessation of the fermentation process. In this study, the dhaD gene encoding glycerol dehydrogenase (GDH) and dhaT gene encoding 1,3-propanediol oxidoreductase (PDOR) were overexpressed in Klebsiella pneumoniae ACCC 10082 to decrease the 3-HPA accumulation and increase the coenzyme NADH supply. By the construction of pTD plasmid, GDH and PDOR were both overexpressed and their enzyme activities were increased by 2.6- and 3.2-fold, respectively. The enzyme activity ratio of PDOR/GDHt (glycerol dehydratase) also was increased. On the other hand, NADH production was enhanced and the ratio of NADH/NAD+ exceeded 1 after the inducement of IPTG for the constructed strain. The two factors enhanced the transformation of 3-HPA to PDO. In the batch and fed-batch fermentation by the constructed strain, the peak of 3-HPA accumulation reduced by 52.2% and 33.3%, respectively, compared with the control. The PDO concentration and yield reached 59.2 g/L and 0.48 mol/mol, respectively. Furthermore, the fed-batch fermentation process appeared easier to be regulated. This work is considered helpful for the further understanding on the PDO metabolic mechanism of K. pneumoniae and also useful for the PDO fermentation in a large-scale bioreactor.

Keywords
dhaT; dhaD; 3-Hydroxypropionaldehyde; 1,3-Propanediol; Klebsiella pneumoniae
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Regulation of 3-hydroxypropionaldehyde accumulation in Klebsiella pneumoniae by overexpression of dhaT and dhaD genes
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 45, Issue 4, 7 October 2009, Pages 305–309
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us