Identification and utilization of a 1,3-propanediol oxidoreductase isoenzyme for production of 1,3-propanediol from glycerol in Klebsiella pneumoniae

Abstract

In a previous study, we showed that 1,3-propanediol (1,3-PD) was still produced from glycerol by the Klebsiella pneumoniae mutant strain defective in 1,3-PD oxidoreductase (DhaT), although the production level was lower compared to the parent strain. As a potential candidate for another putative 1,3-PD oxidoreductase, we identified and characterized a homolog of Escherichia coli yqhD (88% homology in amino acid sequence), which encodes an alcohol dehydrogenase and is well known to replace the function of DhaT in E. coli. Introduction of multiple copies of the yqhD homolog restored 1,3-PD production in the mutant K. pneumoniae strain defective in DhaT. In addition, by-product formation was still eliminated in the recombinant strain due to the elimination of the glycerol oxidative pathway. An increase in NADP-dependent 1,3-PD oxidoreductase activity was observed in the recombinant strain harboring multiple copies of the yqhD homolog. The level of 1,3-PD production during batch fermentation in the recombinant strain was comparable to that of the parent strain; further engineering can generate an industrial strain producing 1,3-propanediol.

YqhD: a broad-substrate range aldehyde reductase with various applications in production of biorenewable fuels and chemicals

“…pneumonia has the inherent ability to produce 1,3-PD from glycerol via DhaB and DhaT. However, like with Emptage's work with recombinant E. coli, 1,3-PD production was observed even after deletion of dhaT (Seo et al 2010). A search of the K. pneumonia genome for a homolog of the E. coli YqhD found a match with 88% amino acid similarity.…”

“…Sulzenbacher's studies showed that Asp194, His267 and His281 coordinate the zinc ion (Figure 2). Note that these sites are conserved in Klebsiella (Seo et al 2010). The coenzyme binding is quite different from the classical Rossmann domain: NADP binds roughly perpendicularly to the parallel sheet of YqhD, instead of the parallel binding seen with horse liver ADH (Sulzenbacher et al 2004).…”

“…Increased expression of this homolog in a ∆dhaD K. pneumonia strain increased glycerol consumption and 1,3-PD yield. The final engineered strain produced 1,3-PD from glycerol at a titer of 7.7 g/L and yield of 0.438 g/g (Seo et al 2010). Alternatively, Zhu et al expressed the E. coli YqhD in K.…”

Metabolic Changes in Klebsiella oxytoca in Response to Low Oxidoreduction Potential, as Revealed by Comparative Proteomic Profiling Integrated with Flux Balance Analysis

“…not alter expression of 1,3-propanediol oxidoreductase (PDOR; EC 1.1.1.202, encoded by dhaT) (46,47). According to previous reports, HOR might be critically involved in 1,3-propanediol production from 3-hydroxypropionaldehyde (47,48). Thus, we postulated that HOR upregulation might contribute to increased 1,3-propanediol production.…”

Influences of 3-hydroxypropionaldehyde and lactate on the production of 1,3-propanediol by Klebsiella pneumoniae

“…The conventional chemical conversion of acrolein (also known as propenal) into 1,3-PD has several drawbacks [2]. Nevertheless, the bioconversion of 1,3-PD from glycerol by Klebsiella pneumoniae has attracted much attention worldwide, and numerous efforts have been made to enhance the 1,3-PD fermentation, such as construction of recombinant K. pneumoniae strains [1][2][3][4][5][6][7][8]. Due to the tremendous growth of the biofuel industry, a glycerol surplus has been created, resulting in a decrease in glycerol prices.…”