白腐真菌血红密孔菌漆酶复合酶预处理烟梗丝的响应面法优化

烟梗是烟草工业的重要副产物,也是宝贵的自然资源。本研究首先利用白腐菌漆酶对烟梗丝进行预处理,提升了添加烟梗丝的卷烟品质;然后分别以木质素、纤维素、半纤维素和果胶的降解率为响应值,采用Box-Behnken设计建立方程模型,对漆酶、纤维素酶、半纤维素酶和果胶酶组成的复合酶预处理烟梗丝条件进行了优化。结果表明：每100g烟梗丝加入30U漆酶,在料液比为35%、温度为30℃、酶解pH为5处理48h的条件下预处理的烟梗丝对提升卷烟品吸效果最佳,烟梗丝中木质素、纤维素、半纤维素和果胶的降解率分别为20.16%、15.10%、7.20%和12.40%;为获得与之相同的各组分降解率,响应面法优化漆酶复合酶最佳处理条件为：每100g烟梗丝加入漆酶14.72U、纤维素酶1.00U、半纤维素酶1.00U、果胶酶8.45U。验证发现烟梗丝各组分降解率实测值与理论值无显著性差异,且显微结构观察显示复合酶处理后的烟梗丝表面致密结构被破坏,孔洞数量明显增加。本研究获得的白腐菌漆酶预处理后的烟梗丝在卷烟中的添加能有效改善卷烟品质,且漆酶复合酶的使用大幅减少了漆酶的用量,降低了漆酶预处理烟梗丝的成本,为废弃烟梗生物质的资源化利用提供了重要依据。

Optimization of pretreatment of tobacco stem by laccase complex enzymes produced by white-rot fungus Pycnoporus sanguineus using response surface methodology

Tobacco stems are the important by-products in the tobacco industry. In this study, the tobacco stems were pretreated with laccase produced by white-rot fungus Pycnoporus sanguineus to improve the quality of cigarette products incorporated with tobacco stems. Using Box-Behnken design, the degradation rates of lignin, cellulose, hemicellulose and pectin were adopted as the response values to build the equation models and optimize the conditions for pretreatment of tobacco stems by complex enzymes consisting of laccase, cellulase, hemicellulase and pectinase. The results showed that the best pretreatment to improve the commodity quality of cigarettes is addition of 30U laccase per 100g tobacco stems. Under the condition of material to liquid ratio 35%, 30°C and pH 5, the degradation rates of lignin, cellulose, hemicellulose and pectin in tobacco stems in 48h were 20.16%, 15.10%, 7.20% and 12.40%, respectively. For obtaining the similar degradation rate, the conditions optimized by response surface method were addition of 14.72U laccase, 1.00U cellulase, 1.00U hemicellulase and 8.45U pectinase per 100g tobacco stems. There was no significant difference between the measured values and the theoretical values of the degradation rate of each component of tobacco stems. Under the treatment of complex enzymes, the fine structure of the tobacco stem surface was destroyed and cavities were increased significantly. It was proved that the quality of cigarettes incorporated with tobacco stems pretreated with laccase produced by P. sanguineus was effectively improved, and the laccase complex enzymes could significantly reduce the applying quantity of laccase and thereby reduced the cost of production.