1,4-butanediol (BDO) is an important commodity molecule that is used as a platform
chemical for the production of polybutylene terephthalate (PBT), elastic fibres (Spandex)
and other materials. The homologous enzyme of E. coli, succinyl-CoA synthetase (sucCD)
and the heterologous malonyl-CoA reductase from Chloroflexus aurantiacus (mcr) are
key enzymes in a heterologous pathway leading to BDO production, which were introduced
into a genome-engineered E. coli MG1655(DE3) Delta ldhA, Delta pflB strain. Knowing
that the expression of recombinant proteins and gene deletions can significantly influence
cellular viability, the present study was carried out to investigate the impact of
the two key enzyme expression on deletion strains, helping us to analyze the physiological
changes of E. coli strains and providing directions for further optimizations in order
to achieve satisfying target product yields.