Abstract
1,2,4-butanetriol
(BT) is a compound of high interest with applications in pharmaceutical and
materials. In this work, we designed a novel biosynthetic pathway for BT from
glucose via a nonessential amino acid homoserine. This non-natural pathway used
an engineered phosphoserine transaminase (SerC
R42W/R77W) to achieve
the deamination of homoserine to 4-hydroxy-2-oxobutanoic acid (HOBA). Three
consecutive enzymes including a lactate dehydrogenase, a 4-hydroxybutyrate
CoA-transferase and a bifunctional aldehyde/alcohol dehydrogenase are used to
catalyze HOBA to BT. To enhance the carbon flux to homoserine, a
homoserine-producing
Escherichia coli was developed by improving the
overexpression of two relevant key genes
metL and
lysC (V339A).
The simultaneous overexpression of the genes encoding these enzymes for the
homoserine-derived BT pathway enabled production of 19.6 mg/L BT from glucose
in the homoserine-producing
E. coli.

© 2023 by the authors; licensee SCIEPublish, SCISCAN co. Ltd. This article is an open access article distributed under the CC BY license (http://creativecommons.org/licenses/by/4.0/).