Fenton联合微波/超声波预处理凤眼莲和甘蔗渣及其酶解产糖工艺

Fenton combined with microwave/ultrasonic pretreatment of Eichhornia crassipes and sugarcane bagasse and their sugar production by enzymatic hydrolysis

选取凤眼莲和甘蔗渣为代表性木质纤维素,以Fenton联合微波/超声波的化学-物理方法,对2种生物质进行预处理,并进行基质化学组分和基质特性、酶解产糖特性及其相互关系研究。对凤眼莲来说,最佳的Fenton-微波预处理为420 W微波预处理3 min+Fenton预处理,预处理后基质的72 h酶解还原糖产率为33.18%;最佳的Fenton-超声波预处理是360 W超声波预处理40 min+Fenton预处理,预处理后基质的72 h酶解还原糖产率为32.61%。甘蔗渣最佳预处理条件分别为:420 W微波预处理3 min+Fenton预处理和480 W超声波预处理50 min+Fenton预处理,预处理后基质的72 h酶解还原糖产率分别为26.47%和24.05%。预处理后样品的保水值相比原料均有提高,纤维素和半纤维素的含量之和也有提高,两者与生物质样品的预处理强度及72 h酶解还原糖产率呈正相关,但预处理前后生物质的结晶度指数与72 h酶解还原糖产率并无明显相关。

Eichhornia crassipes and sugarcane bagasse which were selected as two kinds of typical lignocellulose, were subjected to Fenton reagent combined with microwave/ultrasonic pretreatment. The chemical composition, structural characteristics of the substrate before and after pretreatment, together with the sugar production proper- ties by enzymatic hydrolysis of the substrate were investigated. And the relationships between substrate properties and sugar production properties were analysed. For Eichhornia crassipes, the optimum Fenton-microwave pre- treatment was microwave of 420 W pretreating for 3 min followed by Fenton process. Under this pretreatment, the highest reducing sugar yield of 33.18% could be obtained at enzymatic hydrolysis time of 72 h. The optimum Fenton-ultrasonic pretreatment was ultrasonic wave of 360 W pretreating for 40 rain combined with Fenton pre- treatment. Under this pretreatment, the highest reducing sugar yield of 32.61% could be obtained at enzymatic hydrolysis time of 72 h. For sugarcane bagasse, the optimum pretreatments were microwave of 420 W pretreating for 3 rain followed by Fenton pretreatment and ultrasonic wave of 480 W pretreating for 50 min combined with Fenton pretreatment, respectively. Under these pretreatments, the reducing sugar yields at enzymatic hydrolysis of 72 h were 26.47% and 24.05% , respectively. Compared with those of raw materials, the water retention values, the sum contents of cellulose and hemicellulose of biomass samples after pretreatment all increased, and both were positively correlated to the pretreatment intensity and 72 h reducing sugar yield by enzymatic hydrolysis. However, the crystallinity index （CrI） of biomass before and after the pretreatment had no significant correlation with the 72 h reducing sugar yield by enzymatic hydrolysis.