AUTHOR=Zhu Jieni , Liu Wei , Wang Mengjiao , Di Haiyan , Lü Chuanjuan , Xu Ping , Gao Chao , Ma Cuiqing 

TITLE=Poly-3-hydroxybutyrate production from acetate by recombinant Pseudomonas stutzeri with blocked L-leucine catabolism and enhanced growth in acetate

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2023.1297431

DOI=10.3389/fbioe.2023.1297431

ISSN=2296-4185

ABSTRACT=<p>Acetate is a low-cost feedstock for the production of different bio-chemicals. Electrochemical reduction of CO<sub>2</sub> into acetate and subsequent acetate fermentation is a promising method for transforming CO<sub>2</sub> into value-added chemicals. However, the significant inhibitory effect of acetate on microbial growth remains a barrier for acetate-based biorefinery. In this study, the deletion of genes involved in <sc>L</sc>-leucine degradation was found to be beneficial for the growth of <italic>Pseudomonas stutzeri</italic> A1501 in acetate. <italic>P. stutzeri</italic> (Δ<italic>pst_3217</italic>), in which the hydroxymethylglutaryl-CoA lyase catalyzing <italic>β</italic>-hydroxy-<italic>β</italic>-methylglutaryl-CoA into acetyl-CoA and acetoacetate was deleted, grew faster than other mutants and exhibited increased tolerance to acetate. Then, the genes <italic>phbCAB</italic> from <italic>Ralstonia eutropha</italic> H16 for poly-3-hydroxybutyrate (PHB) biosynthesis were overexpressed in <italic>P. stutzeri</italic> (∆<italic>pst_3217</italic>) and the recombinant strain <italic>P. stutzeri</italic> (∆<italic>pst_3217</italic>-<italic>phbCAB</italic>) can accumulate 0.11 g L<sup>−1</sup> PHB from commercial acetate. Importantly, <italic>P. stutzeri</italic> (∆<italic>pst_3217</italic>-<italic>phbCAB</italic>) can also use CO<sub>2</sub>-derived acetate to produce PHB and the accumulated PHB accounted for 5.42% (w/w) of dried cell weight of <italic>P. stutzeri</italic> (∆<italic>pst_3217</italic>-<italic>phbCAB</italic>).</p>