酸性亚硫酸盐预处理对棉杆糖化效率的影响

Effects of Bisulfite Pretreatment on Enzymatic Saccharification of Cotton Stalk

采用酸性亚硫酸盐法预处理棉杆进行生物质转化,研究了硫酸用量、亚硫酸氢钠用量、预处理温度和保温时间等对棉杆底物酶水解效率和棉杆组分溶出的影响,并研究了棉杆酶水解过程中添加木素磺酸盐对棉杆底物酶水解效率的影响。结果表明,硫酸用量的增加可以明显提高半纤维素的降解溶出,亚硫酸氢钠用量的提高可以增加木素的磺化溶出,一定的预处理温度和保温时间是必要的,但过高的预处理温度和过长的保温时间对棉杆酶解效率没有益处。综合考虑,酸性亚硫酸盐预处理棉杆的最佳条件为:硫酸用量2.2%,亚硫酸氢钠用量8.0%,预处理温度170℃,保温时间40 min。纤维素酶用量为15 FPU/g(绝干底物)时,棉杆底物酶水解糖化率为83.9%。只添加商品木素磺酸盐,添加量为3.0%(对绝干底物),棉杆底物纤维酶水解转化率达到93.4%,基本达到工业生产的标准;黑液可以取代部分商品木素磺酸盐,但全部取代,效果略差。

Bisulfite pretreatment （SPORL） on bioconversion of cotton stalk was investigated. The dosages of H2SO4 and NaHSO3, pretreatment temperature, and duration time were the main factors of bisulfite pretreatment on enzymatic saccharification of cotton stalk and compositions＇ dissolution from cotton stalk. The effects of adding lignosulfonate during enzymatic hydrolysis of cotton stalk were also studied in this study. Hemicelluloses＇ degradation was significantly improved by increasing the dosage of sulfuric acid, and lignin dissolution was improved by increasing the amount of sodium bisulfite. The suitable pretreatment temperature and duration time was necessary. Considering all factors, the optical pretreatment conditions were as follows： sulfuric acid dosage of 2.2%, sodium bisulfite charge of 8.0%, pretreatment temperature of 170℃, and duration time of 40 min. The highest cellulose conversion of 83.9% from cotton stalk substrate pretreated by the above optical conditions by adding enzyme dosage of 15 FPU/g （on o.d. substrate）. It was also found that the cellulose enzymatic hydrolysis yield of 93.4% was obtained by adding market lignosulfonate of 3.00, and the waste liquor from pretreatment could take part of market ligosulfonate.