前处理对玉米秸秆蒸汽爆破效果的影响

为提高纤维乙醇生产过程中秸秆的预处理效果,该文研究了水预浸和CaO前处理对蒸汽爆破和酶解糖化的影响,并利用场发射扫描电镜(FE-SEM)、X-射线衍射仪(XRD)及傅里叶红外光谱仪(FTIR)对其影响机制进行了分析。结果表明:玉米秸秆经30%水(水料质量比30:100)预浸5d、经2%CaO(CaO与秸秆质量比2:100)处理3d或经30%水和2%CaO协同处理1d后再进行蒸汽爆破均可显著提高蒸汽爆破对木质素的降解,降解率由单独蒸汽爆破的20.6%分别提高到27.8%、35.1%和30.9%。玉米秸秆经3种复合预处理和酶解糖化后总糖浓度分别为3.81、3.59和3.46g/100mL,糖得率分别为42.2%、39.8%和38.3%,比单独蒸汽爆破预处理分别提高了23.7%、16.6%和12.3%。水预浸或CaO复合蒸汽爆破预处理后秸秆结构破坏严重,秸秆相对结晶度由单独蒸汽爆破的42.6%分别提高到47.0%和54.5%。水浸泡或CaO前处理可提高蒸汽爆破预处理效果和后期糖化效果,且所用试剂价格低廉,可以应用推广。

Effects of pretreatments on steam exposition efficiency of corn stalk

To enhance the pretreatment effect for production of cellulose ethanol, the influences of water immersion and CaO treatments before steam explosion on the structure destruction of corn stalks and enzymatic saccharification were studied. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were involved in this study. The results showed that compared to the control (corn stalks pretreated with steam explosion), corn stalk immersed with 30% water (mass ratio of water to corn stalk was 30:100) for 5 days, or treated with 2% CaO(mass ratio of CaO to corn stalk is 2:100) for 3days, or treated with 2% CaO and 30% water for 1 day before steam explosion enhanced the lignin degradation rate from 20.7% to 27.8%, 35.1% and 30.9%, respectively; the concentrations of reducing sugars in the three pretreatments were 3.81, 3.59 and 3.46 g/100mL respectively; and the sugar yields in the three pretreatments were 42.2%, 39.8% and 38.3% and increased by 23.7%, 16.6% and 12.3% respectively compared with the control. Pretreatment with 30% water immersion for 5 days and 2% CaO for 3 days intensified the destruction of surface structures and the degradation of lignin, the relative crystallinity of which increased by 47.0% and 54.5% respectively compared to the control(42.6%). Pretreatment with 30% water or 2%CaO exhibited high efficiency and sugar yields. It is benefit for the promotion of this technology with low-price and non-contaminating reagents.