초록
<P><B>Abstract</B></P> <P>Xylose-assimilating pathways were constructed in the parental <I>Pediococcus acidilactici</I> strain and evolutionarily adapted to yield a highly stable co-fermentation strain for <SMALL>L</SMALL>-lactic acid production. The phosphoketolase pathway (PK) was blocked for reduction of acetic acid generation by disrupting phosphoketolase (<I>pkt</I>) gene. The pentose phosphate pathway (PPP) was reconstructed for xylose assimilation by integrating four heterologous genes encoding transketolase (<I>tkt</I>), transaldolase (<I>tal</I>), xylose isomerase (<I>xylA</I>) and xylulokinase (<I>xylB</I>) into the <I>P. acidilactici</I> chromosome. The xylose-assimilating ability of the constructed strain was significantly improved by long term adaptive evolution. The engineered strain was applied to the simultaneous saccharification and co-fermentation (SSCF) under high solids loading of wheat straw. The <SMALL>L</SMALL>-lactic acid titer, productivity and xylose conversion reached the record high at 130.8±1.6g/L, 1.82±0.0g/L/h, and 94.9±0.0%, respectively. This study provided an important strain and process prototype for production of high titer cellulosic <SMALL>L</SMALL>-lactic acid.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Xylose assimilation to <SMALL>L</SMALL>-lactic acid was engineered in <I>Pediococcus acidilactici</I>. </LI> <LI> Adaptive evolution significantly accelerated xylose assimilation. </LI> <LI> SSCF of wheat straw leads to record high cellulosic <SMALL>L</SMALL>-lactic acid and xylose conversion. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>