三元低共熔溶剂预处理甘蔗渣的酶解性能研究

Enzymatic Digestibility of Ternary Deep Eutectic Solvent Pretreated Sugarcane Bagasse

以制糖工业副产物甘蔗渣(SCB)作为木质纤维原料,使用具有优异相转移催化能力的三乙基苄基氯化铵(TEBAC)、无毒无害的甘油(GL),以及高价态路易斯酸六水合氯化铝(ACH)组成的三元低共熔溶剂(DES)对SCB进行预处理,系统考察了DES物质的量之比、预处理温度、预处理时间、固液质量比对SCB中各组分含量和纤维素酶解效率的影响。研究结果表明:最佳预处理条件为n TEBAC∶n GL∶n ACH为1∶2∶0.05、预处理时间30 min、预处理温度120℃和固液质量比1∶15,此优化条件下木质素去除率达到(86.23±2.11)%,纤维素保留率为(94.51±2.03)%,酶解纤维素转化率达到(98.21±1.02)%,相较于未处理SCB提高了2倍,葡萄糖得率高达(81.94±1.98)%,提高了1.5倍。SEM、FT-IR和XRD分析结果表明:三元DES预处理能够有效去除SCB中的木质素和半纤维素,从而使纤维素的结晶度由未预处理的41.19%提高到预处理后的65.87%。DES经过5次循环利用后,纤维素转化率和葡萄糖得率仍达到(92.36±1.64)%和(74.45±1.12)%,依旧保持了较好的预处理效果。

Sugarcane bagasse(SCB),a by-product of the sugar industry,was used as a lignocellulosic raw material.In the present study,a ternary deep eutectic solvent(DES)composed of triethylbenzyl ammonium chloride(TEBAC)with strong phase transfer catalytic ability,non-toxic and harmless glycerol(GL)and high-valence Lewis acid aluminum chloride hexahydrate(ACH),was used to pretreat SCB.The effects of molar ratio of ternary DES,reaction temperature,reaction time and solid-liquid mass ratio on the content of each component in SCB and cellulase enzymatic digestibility were systematically investigated.The results showed that the optimal pretreatment conditions were as follows:the molar ratio of n TEBAC∶n GL∶n ACH was 1∶2∶0.05,the pretreatment time was 30 min,the pretreatment temperature was 120℃and the solid-liquid ratio was 1∶15.Under these conditions,the lignin removal rate was(86.23±2.11)%,and the cellulose retention rate was(94.51±2.03)%.The conversion of enzymatic hydrolysis cellulose was(98.21±1.02)%,which was 2 times higher than that of untreated SCB,and the yield of glucose was(81.94±1.98)%,which was increased by 1.5 times.The results of SEM,FT-IR and XRD analysis showed that ternary DES pretreatment could effectively remove lignin and hemicellulose from SCB,and the crystallinity of cellulose increased from 41.19%to 65.87%after pretreatment.Importantly,DES still maintained good pretreatment performance after 5 cycles of recycling,and the cellulose conversion rate and glucose yield reached(92.36±1.64)%and(74.45±1.12)%,respectively.