초록
<P><B>Abstract</B></P> <P>Rice straw was pretreated with sodium hydroxide (NaOH) before subsequent use for succinate production by <I>Escherichia coli</I> KJ122 under simultaneous saccharification and fermentation (SSF). The NaOH pretreated rice straw was significantly enhanced lignin removal up to 95%. With the optimized enzyme loading of 4% cellulase complex + 0.5% xylanase (endo-glucanase 67 CMC-U/g, β-glucosidase 26 pNG-U/g and xylanase 18 CMC-U/g dry biomass), total sugar conversion reached 91.7 ± 0.8% (w/w). The physicochemical analysis of NaOH pretreated rice straw indicated dramatical changes in its structure, thereby favoring enzymatic saccharification. In batch SSF, succinate production of 69.8 ± 0.3 g/L with yield and productivity of 0.84 g/g pretreated rice straw and 0.76 ± 0.02 g/L/h, respectively, was obtained. Fed-batch SSF significantly improved succinate concentration and productivity to 103.1 ± 0.4 g/L and 1.37 ± 0.07 g/L/h with a comparable yield. The results demonstrated a feasibility of sequential saccharification and fermentation of rice straw as a promising process for succinate production in industrial scale.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This report is a pioneer study in fermentative succinate production from rice straw. </LI> <LI> Enzymatic saccharification of NaOH pretreated rice straw achieved 90% sugar yield. </LI> <LI> Succinate at 103 g/L (0.84 g/g pretreated rice straw) was obtained by <I>E. coli</I> KJ122. </LI> <LI> The overall succinate production yield of 0.49 g/g rice straw has been proposed. </LI> <LI> Rice straw is a promising agricultural feedstock for an economic succinate production. </LI> </UL> </P>