AUTHOR=Kalantari Aida , Chen Tao , Ji Boyang , Stancik Ivan A. , Ravikumar Vaishnavi , Franjevic Damjan , Saulou-Bérion Claire , Goelzer Anne , Mijakovic Ivan 

TITLE=Conversion of Glycerol to 3-Hydroxypropanoic Acid by Genetically Engineered Bacillus subtilis

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00638

DOI=10.3389/fmicb.2017.00638

ISSN=1664-302X

ABSTRACT=<p>3-Hydroxypropanoic acid (3-HP) is an important biomass-derivable platform chemical that can be converted into a number of industrially relevant compounds. There have been several attempts to produce 3-HP from renewable sources in cell factories, focusing mainly on <italic>Escherichia coli, Klebsiella pneumoniae</italic>, and <italic>Saccharomyces cerevisiae</italic>. Despite the significant progress made in this field, commercially exploitable large-scale production of 3-HP in microbial strains has still not been achieved. In this study, we investigated the potential of <italic>Bacillus subtilis</italic> as a microbial platform for bioconversion of glycerol into 3-HP. Our recombinant <italic>B. subtilis</italic> strains overexpress the two-step heterologous pathway containing glycerol dehydratase and aldehyde dehydrogenase from <italic>K. pneumoniae</italic>. Genetic engineering, driven by <italic>in silico</italic> optimization, and optimization of cultivation conditions resulted in a 3-HP titer of 10 g/L, in a standard batch cultivation. Our findings provide the first report of successful introduction of the biosynthetic pathway for conversion of glycerol into 3-HP in <italic>B. subtilis</italic>. With this relatively high titer in batch, and the robustness of <italic>B. subtilis</italic> in high density fermentation conditions, we expect that our production strains may constitute a solid basis for commercial production of 3-HP.</p>