BioChem - DOS

Constructing xylose-assimilating pathways in Pediococcus acidilactici for high titer D-lactic acid fermentation from corn stover feedstock

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

Qiu, Zhongyang; Gao, Qiuqiang; Bao, Jie

<P><B>Abstract</B></P> <P>Xylose-assimilating pathway was constructed in a <SMALL>D</SMALL>-lactic acid producing <I>Pediococcus acidilactici</I> strain and evolutionary adapted to yield a co-fermentation strain <I>P. acidilactici</I> ZY15 with 97.3g/L of <SMALL>D</SMALL>-lactic acid and xylose conversion of 92.6% obtained in the high solids content simultaneous saccharification and co-fermentation (SSCF) of dry dilute acid pretreated and biodetoxified corn stover feedstock. The heterologous genes encoding xylose isomerase (<I>xylA</I>) and xylulokinase (<I>xylB</I>) were screened and integrated into the <I>P. acidilactici</I> chromosome. The metabolic flux to acetic acid in phosphoketolase pathway was re-directed to pentose phosphate pathway by substituting the endogenous phosphoketolase gene (<I>pkt</I>) with the heterologous transketolase (<I>tkt</I>) and transaldolase (<I>tal</I>) genes. The xylose-assimilating ability of the newly constructed <I>P. acidilactici</I> strain was significantly improved by adaptive evolution. This study provided an important strain and process prototype for high titer <SMALL>D</SMALL>-lactic acid production from lignocellulose feedstock with efficient xylose assimilation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Xylose-assimilating pathways were constructed in the chromosome of <I>Pediococcus acidilactici</I>. </LI> <LI> Xylose assimilation was significantly accelerated by adaptive evolution. </LI> <LI> High corn stover solids content SSCF was conducted. </LI> <LI> 97.3g/L of <SMALL>D</SMALL>-lactic acid with 92.6% of xylose conversion ratio was obtained using corn stover. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

2017

Elsevier

0960-8524

245

2

pp.1369-1376

10.1016/j.biortech.2017.05.128

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART78806238

Pediococcus acidilactici; Xylose-assimilating pathway; D-Lactic acid; Adaptive evolution; Lignocellulose