揉搓与稀碱联合预处理对水稻秸秆酶解产糖率及结构的影响

Study on the effects of rubbing-alkali pretreatment on enzymatic hydrolysis reducing sugar yield and structure of rice straw

为了提高水稻秸秆中木质纤维素的利用率,尽可能减少预处理过程中化学物质的使用量,开展了揉搓与稀碱联合预处理对水稻秸秆酶解产糖率及结构影响的研究,并通过正交试验获得最佳预处理效果的条件。研究采用3,5-二硝基水杨酸法测定不同预处理酶解还原糖的含量,并通过硅含量测定,傅立叶变换红外光谱(FTIR),X射线衍射(XRD)和秸秆成分测定对预处理后的水稻秸秆进行成分和结构分析。结果表明,揉搓预处理不能明显提升水稻秸秆的酶解产糖率,但能够加强稀碱的作用效果,揉搓与稀碱联合预处理后的秸秆酶解产糖率达33. 63%,明显高于原始秸秆和单独稀碱预处理秸秆;揉搓预处理能够去除秸秆表面33. 40%的硅,与原始秸秆及单独稀碱预处理秸秆之间差异显著,但与揉搓和稀碱联合预处理之间差异不明显; FTIR、XRD和成分测定结果显示,揉搓和稀碱联合预处理能够有效去除秸秆中的木质素,使纤维素的结晶度提升;正交试验发现氢氧化钙质量浓度6%、反应温度40℃,反应时间6 d时,联合预处理酶解产糖率最佳。研究结果将为秸秆高效资源化利用提供理论依据和指导。

In order to increase the utilization ratio of lignocellulose in rice straw and reduce the amount of chemicals used in pretreatment process,the effects of combined pretreatment with rubbing and dilute alkali on the sugar yield and structure of rice straw were studied,and the optimum pretreatment conditions were obtained through orthogonal experiment.3,5-two nitro salicylic acid method was used to determine the content of enzymatic hydrolysis reducing sugar in different pretreatments,and the composition and structure of the pretreated rice straw were analyzed by silica content determination,Flourier transformation infrared spectroscopy(FTIR),X ray diffraction(XRD)and composition determination.The results showed that the rubbing pretreatment did not significantly increase the rate of enzymatic hydrolysis sugar of rice straw,but it could enhance the effect of dilute alkali.The enzymatic hydrolysis sugar rate of straw pretreated with rubbing-alkali was 33.63%,which was significantly higher than that of the original straw and straw pretreated with dilute alkaline alone.Rubbing pretreatment could remove 33.40%of the surface silicon of straw,which was significantly higher than that of the original straw and the straw pretreated with dilute alkali alone,but there was no obvious difference between straw pretreated with rubbing and rubbing-alkali.The results of FTIR,XRD and composition determination showed that the combined pretreatment could dissolve lignin efficiently,and increase the crystallinity of cellulose.The orthogonal experiment results showed that the yield of reducing sugar was highest when the concentration of calcium hydroxide was 6%,the reaction temperature was 40℃and the reaction time was six days.The results would provide a theoretical basis and guidance for efficient utilization of straw.