BioChem - DOS

The myo-inositol/proton symporter IolT1 contributes to D-xylose uptake in Corynebacterium glutamicum

Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformations, production technologies

Brü sseler, Christian; Radek, Andreas; Tenhaef, Niklas; Krumbach, Karin; Noack, Stephan; Marienhagen, Jan

<P><B>Abstract</B></P> <P> <I>Corynebacterium glutamicum</I> has been engineered to utilize <SMALL>D</SMALL>-xylose as sole carbon and energy source. Recently, a <I>C. glutamicum</I> strain has been optimized for growth on defined medium containing <SMALL>D</SMALL>-xylose by laboratory evolution, but the mutation(s) attributing to the improved-growth phenotype could not be reliably identified. This study shows that loss of the transcriptional repressor IolR is responsible for the increased growth performance on defined <SMALL>D</SMALL>-xylose medium in one of the isolated mutants. Underlying reason is derepression of the gene for the glucose/<I>myo</I>-inositol permease IolT1 in the absence of IolR, which could be shown to also contribute to <SMALL>D</SMALL>-xylose uptake in <I>C. glutamicum</I>. IolR-regulation of <I>iolT1</I> could be successfully repealed by rational engineering of an IolR-binding site in the <I>iolT1</I>-promoter. This minimally engineered <I>C. glutamicum</I> strain bearing only two nucleotide substitutions mimics the IolR loss-of-function phenotype and allows for a high growth rate on <SMALL>D</SMALL>-xylose-containing media (&micro;<SUB>max</SUB> = 0.24 &plusmn; 0.01 h<SUP>&minus;1</SUP>).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Deletion of <I>iolR</I> improves growth of <I>C. glutamicum</I> on <SMALL>D</SMALL>-xylose containing media. </LI> <LI> Permease IolT1 contributes to <SMALL>D</SMALL>-xylose uptake in <I>C. glutamicum.</I> </LI> <LI> Engineering of the <I>iolT1</I> promoter renders <I>iolR</I>-deletion unnecessary. </LI> <LI> Minimally engineered <I>C. glutamicum</I> WMB2 P<SUB>O6</SUB> <I>iolT1</I> allows for high growth rates on <SMALL>D</SMALL>-xylose. </LI> </UL> </P>

2018

Elsevier

0960-8524

249

pp.953-961

10.1016/j.biortech.2017.10.098

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART80375948

Corynebacterium glutamicum; D-xylose; Lignocellulosic biomass; Weimberg pathway; Isomerase pathway