吐温-80及碱预处理对饲用稻草木质素含量和纤维素酶解产糖的影响

探讨了添加1‰吐温-80非离子表面活性剂和不同浓度碱预处理对稻草秸秆木质素及纤维素的影响,并对预处理前后的稻草进行了X射线衍射光谱(XRD)分析,从结晶度的变化综合分析了预处理对纤维素酶解的影响。实验结果表明:在30℃下添加1‰吐温-80非离子表面活性剂时,用4%NaOH预处理稻草秸秆,木质素含量降至6.5%(较未处理稻草下降了41.9%),灰分值仅占6.9%,具有较好的粗饲料价值;在121℃(0.1 MPa)下添加1‰吐温-80非离子表面活性剂时,用4%NaOH预处理稻草秸秆,木质素含量降至2.8%(较未处理稻草下降了74.5%),酶解还原糖达到393.9 mg/g,纤维素糖化率为59.3%(较未处理稻草提高了2.4倍)。XRD分析显示,在较温和的条件下,低浓度碱预处理稻草秸秆,对纤维素结晶区带来的影响相对于无定形区弱,不足以引起纤维素结晶度的降低。

Effects of Tween-80 and Alkali Pretreatment on the Content of Lignin of Straw and Enzymatic Hydrolysis

Abstract： The effects of alkali pretreatment conditions on the content of lignin, cellulose of straw by addition of tween-80 at 1‰ were studied, the crystallinity of straw before and after pretreatrnents was estimated by X-ray diffraction （XRD）, effects of different pretreatments on variations of composition and enzymatic hydrolysis of cellulose were seen from the results. The results show that the content of lignin was 6.5% （41.9% lower than the untreated sample） and the content of ash was merely 6.9% by pretreatment （4% NaOH by addition of Tween-80 at 1%0, 30℃）, this pretreatment was applied to get rough feed; the content of lignin was 2.8% （74.5% lower than the untreated sample） by alkaline pretreatment （4% NaOH by addition of Tween-80 at 1%0, 121 ℃）, the maximum yield of reducing sugars from rice straw was 393.9 mg per g and the ratio of conversion of cellulose was 59.3% （increasing 2.4 times than the untreated sample）. XRD showed that after the low concentration of alkali pretreated rice straw in relatively mild conditions, crystalline of cellulose was destroyed weaker than amorphous area, therefore it was not enough to decrease the crystallinity index （CrI） of cellulose.