초록
<P><B>Abstract</B></P> <P> <I>Alternanthera philoxeroides</I>, a notorious invasive aquatic weed, is a typical lignocellulosic feedstock for fermentative biohydrogen production. To improve the dark fermentation performance, steam-heated acid pretreatment and enzymolysis were employed to release reducing sugars from <I>A. philoxeroides</I>, and <I>Enterobacter aerogenes</I> ZJU1 mutagenized by <SUP>60</SUP>Co-γ irradiation was used as the inoculum. Dilute acid accompanied by steam heating significantly disrupted the fiber structures of <I>A. philoxeroides</I>. Scanning electron microscopic images revealed that many pores and fissures were generated in the surface of <I>A. philoxeroides</I> after pretreatment. X-ray diffraction and Fourier transform infrared spectroscopy analyses showed that the pretreatment facilitated the transformation of cellulose I to cellulose II in <I>A. philoxeroides</I> biomass, resulting in the increase of amorphous regions and the decrease of crystallinity. Under the optimum pretreatment condition (1.0 v/v% H<SUB>2</SUB>SO<SUB>4</SUB>, 135 °C for 15 min), the reducing sugar yield reached 0.354 g/g <I>A. philoxeroides</I>, which was further increased to 0.575 g/g <I>A. philoxeroides</I> after enzymolysis. The biohydrogen yield increased by 59.9% from 38.9 mL/g volatile solids (VS) of raw <I>A. philoxeroides</I> to 62.2 mL/gVS of the pretreated one. As compared to the wild strain, <I>E. aerogenes</I> ZJU1 contributed to an increase of 31.8% in the biohydrogen yield from pretreated <I>A. philoxeroides</I>. Further optimization of bacteria suspensions significantly increased the maximum biohydrogen production rate from 1.42 to 4.64 mL/gVS/h, advanced the biohydrogen production peak, and resulted in an increase of 42.8% in biohydrogen yield to 89.8 mL/gVS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Alternanthera philoxeroides</I> was firstly used for fermentative hydrogen production. </LI> <LI> <SUP>60</SUP>Co-γ mutagenized <I>Enterobacter aerogenes</I> ZJU1 was employed as inoculum. </LI> <LI> Steam-heated acid pretreatment led to high reducing sugars from <I>A. philoxeroides</I>. </LI> <LI> SEM, XRD, and FTIR revealed microstructural changes of biomass after pretreatment. </LI> <LI> Highest biohydrogen yield of 89.8 mL/gVS was obtained using actual biomass waste. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>