초록
<P><B>Abstract</B></P> <P>Solid acid is a new acid that is safe and green, which has been widely used in the fields of acid pickling. In this study, we adopted solid acid to pretreat corn stover and used the pretreated corn stover in the fermentation of <SMALL>D</SMALL>-lactic acid. Finally, we obtained optimal conditions for the pretreatment of corn stover by solid acid: digestion temperature of 120°C, digestion time of 80min, and solid acid concentration of 1.5%. Then adding cellulase of 30FPU/g, the conversion rate of glucose reached 71.06% after enzymatic hydrolysis for 72h. In addition, the changes of corn stover structure after pretreatment were further represented by using scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). At the same time, we used the pretreated corn stover as fermentation substrate and <I>Lactobacillus. delbrueckii</I> sp. <I>bulgaricus</I> as the starting strain to produce <SMALL>D</SMALL>-lactic acid. The yield reached 18g/L, with the optical purity being 99%e.e. This research has provided a new way to comprehensively utilizae corn stover.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Corn stover were pretreated with 1.5% (w/v) solid acid at 120°C. </LI> <LI> Pretreated corn stover showed 71.93% glucose yield in the enzymatic hydrolysis. </LI> <LI> Successive acid fermentation of pretreated corn stover gave 180g <SMALL>D</SMALL>-lactic acid kg<SUP>−1</SUP> CS. </LI> <LI> The final product optical purity was 99%e.e. </LI> </UL> </P>