Wang, Q;
Jiang, W;
Cai, Y;
Tišma, M;
Baganz, F;
Shi, J;
Lye, GJ;
... Hao, J; + view all
(2024)
2-Hydroxyisovalerate production by Klebsiella pneumoniae.
Enzyme and Microbial Technology
, 172
, Article 110330. 10.1016/j.enzmictec.2023.110330.
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Abstract
2-Hydroxyisovalerate is a valuable chemical that can be used in the production of biodegradable polyesters. In nature, it was only produced at a very low level by Lactococcus lactis. 2-Ketoisovalerate is an intermediate metabolite of the branched-chain amino acid biosynthesis pathway, and Klebsiella pneumoniae ΔbudAΔldhA (Kp ΔbudAΔldhA) was a 2-ketoisovalerate producing strain. In this research, 2-hydroxyisovalerate was identified as a metabolite of Kp ΔbudAΔldhA, and its synthesis pathway was revealed. It was found that 2-ketoisovalerate and 2-hydroxyisovalerate were produced by Kp ΔbudA and Kp ΔbudAΔldhA, but not by Kp ΔbudAΔldhAΔilvD in which the 2-ketoisovalerate synthesis was blocked. budA, ldhA, and ilvD encode α-acetolactate decarboxylase, lactate dehydrogenase, and dihydroxy acid dehydratase, respectively. Thus, it was deduced that 2-hydroxyisovalerate was synthesized from 2-ketoisovalerate. Isoenzymes of ketopantoate reductase PanE, PanE2, and IlvC were suspected of being responsible for this reaction. Kinetic parameters of these enzymes were detected, and they all hold the 2-ketoisovalerate reductase activities. PanE and PanE2 use both NADH and NADPH as co-factors. While IlvC only uses NADH as a co-factor. Over-expression of panE, panE2, or ilvC in Kp ΔbudAΔldhA all enhanced the production of 2-hydroxyisovalerate. Accordingly, 2-hydroxyisovalerate levels were reduced by knocking out panE or panE2. In fed-batch fermentation, 14.41 g/L of 2-hydroxyisovalerate was produced by Kp ΔbudAΔldhA-panE, with a substrate conversion ratio of 0.13 g/g glucose.
| Type: | Article |
|---|---|
| Title: | 2-Hydroxyisovalerate production by Klebsiella pneumoniae |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.enzmictec.2023.110330 |
| Publisher version: | https://doi.org/10.1016/j.enzmictec.2023.110330 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions. |
| Keywords: | Klebsiella pneumoniae, 2-Hydroxyisovalerate, 2-Ketoisovalerate, panE, ilvC |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Biochemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10181590 |
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