氢氧化钠预处理对甘蔗渣酶解和发酵性能的影响

Impacts of NaOH Pretreatment on Enzymolysis and Fermentation Performance of Sugarcane Bagasse

采用氢氧化钠预处理甘蔗渣,通过单因素和正交试验考察了不同预处理条件对甘蔗渣酶解和发酵性能的影响,并进一步分析了比表面积和木质素含量对酶解性能的影响。结果表明:预处理温度、氢氧化钠质量分数及预处理时间对酶解和发酵效率影响较为显著,最佳的预处理条件为:温度85℃、时间11 h、NaOH质量分数4.5%,在此优化条件下预处理的甘蔗渣,含纤维素56.46%,与原料相比提高了46.16%;半纤维素20.30%、Klason木质素5.79%,与原料相比分别降低了15.77%和72.87%,酶解36 h的还原糖得率为0.69 g/g(以甘蔗渣质量计)。经过氢氧化钠预处理后的甘蔗渣比表面积显著增加(由原料的0.07 m^2/g最大可增加到1.07 m^2/g),木质素显著降低,有利于提高酶解和发酵效率。当比表面积超过0.30 m^2/g时,酶解初始速率和酶解效率达到平衡;当木质素低于11%时,酶解效率达到平衡。

The impacts of different pretreatment conditions on enzymolysis and fermentation performance of sugarcane bagasse（ SCB） pretreated by NaOH were investigated by single factor analysis and orthogonal experimental design. The effects of specific surface area and lignin content on enzymolysis of SCB were further studied. The results showed that the pretreatment temperature,time and mass fraction of NaOH significantly affected the enzymolysis and fermentation efficiency of the pretreated SCB. The optimal conditions for NaOH pretreatment were mass fraction of NaOH 4. 5 %,11 h and 85 ℃. Under these conditions,the cellulose content of the pretreated SCB reached 56. 46 % and increased by 46. 16 % compared with the raw SCB. And the xylan and Klason lignin contents reached 20. 30 % and 5. 79 %,which decreased by 15. 77 % and 72. 87 %,respectively. The reducing sugar yield reached 0. 69 g/g substrate after 36 h enzymolysis. The specific surface area of pretreated SCB significantly increased（ the maximum value of 1. 07 m^2/g from 0. 07 m^2/g of the raw was obtained）,while the lignin content decreased significantly. Both of them were beneficial for the enhancement of the enzymolysis and fermentation efficiency. It was found that when the specific surface area surpassed 0. 30 m^2/g,the initial enzymolysis rate and final efficiency could reach a balance. Besides,when the the lignin content was lower than 11 %,the enzymolysis efficiency reached a balance.