Engineering of artificial microbial consortia of <i>Ralstonia eutropha</i> and <i>Bacillus subtilis</i> for poly(3-hydroxybutyrate-<i>co</i>-3-hydroxyvalerate) copolymer production from sugarcane sugar without precursor feeding

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P> <I>Ralstonia eutropha</I> is a well-known microbe reported for polyhydroxyalkonate (PHA) production, and unable to utilize sucrose as carbon source. Two strains, <I>Ralstonia eutropha</I> H16 and <I>Ralstonia eutropha</I> 5119 were co-cultured with sucrose hydrolyzing microbes (<I>Bacillus subtilis</I> and <I>Bacillus amyloliquefaciens</I>) for PHA production<I>.</I> Co-culture of <I>B. subtilis:R. eutropha</I> 5119 (BS:RE5) resulted in best PHA production (45% w/w dcw). Optimization of the PHA production process components through response surface resulted in sucrose: NH<SUB>4</SUB>Cl:<I>B. subtilis</I>: <I>R. eutropha</I> (3.0:0.17:0.10:0.190). Along with the hydrolysis of sucrose, <I>B. subtilis</I> also ferments sugars into organic acid (propionic acid), which acts as a precursor for HV monomer unit. Microbial consortia of BS:RE5 when cultured in optimized media led to the production of poly(3-hydroxybutyrate-<I>co</I>-3-hydroxyvalerate) (P(3HB-<I>co</I>-3HV) with 66% w/w of dcw having 16 mol% HV fraction<I>.</I> This co-culture strategy overcomes the need for metabolic engineering of <I>R. eutropha</I> for sucrose utilization, and addition of precursor for copolymer production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Ralstonia eutropha</I> 5119 strain unable to utilize sucrose as carbon source. </LI> <LI> <I>Bacillus subtilis</I> hydrolyze sucrose into free sugars and produce propionic acid. </LI> <LI> <I>Ralstonia eutropha</I> 5119: <I>Bacillus subtilis</I> produce P(3HB-<I>co</I>-3HV) by 66% w/w of dcw. </LI> <LI> Population dynamics study shows both microbes are compatible with each other. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>