Abstract

Present study aims at sustainable utilization of sugarcane bagasse (SCB) for production of valuable prebiotic xylooligosaccharides (XOS) along with second generation ethanol. Fractionation of SCB into hemicellulose rich liquid fraction and cellulose rich solid residue was achieved using alkaline treatment. Carbohydrate rich precipitate obtained from liquid fraction was utilized for XOS production using inhouse produced endoxylanase. XOS production from SCB xylan was optimized by employing response surface methodology. Under optimized conditions, maximum XOS yield was 227.72 mg/g of carbohydrate rich precipitates. The solid residue obtained after alkaline pretreatment was used for ethanol fermentation by prehydrolysis and simultaneous saccharification and fermentation (P-SSF) process using cellulolytic enzyme cocktail and Saccharomyces cerevisiae SM1. Maximum ethanol concentration, productivity and yield were 79.76 ± 0.16 g/L, 0.83 g/L/h and 69.38%, respectively by employing P-SSF process. Based on the experimental data it can be predicted that bioconversion of 100 g raw SCB can yield 6.26 g of XOS (DP 2-DP 5), 15.95 g ethanol and 1.44 g of xylitol. Present investigation reports an integrated process for effective bioconversion of SCB into value added products by maximum utilization of cellulosic and hemicellulosic fractions simultaneously using indigenously produced fungal enzymes.

摘要

目前的研究旨在可持续利用甘蔗渣（SCB）来生产有价值的益生元低聚木糖（XOS）以及第二代乙醇。使用碱处理将SCB分级分离成富含半纤维素的液体部分和富含纤维素的固体残渣。从液体部分获得的富含碳水化合物的沉淀物被用于使用内部生产的木聚糖内切酶生产低聚木糖。采用响应面法优化了 SCB 木聚糖的 XOS 生产。在优化条件下，最大 XOS 产量为 227.72 mg/g 富含碳水化合物的沉淀物。碱预处理后获得的固体残渣通过预水解和同时糖化发酵（P-SSF）工艺使用纤维素分解酶混合物进行乙醇发酵，酿酒酵母SM1。采用P-SSF工艺，最大乙醇浓度、生产率和收率分别为79.76±0.16 g/L、0.83 g/L/h和69.38%。根据实验数据可以预测，100 g粗SCB生物转化可产生6.26 g低聚木糖（DP 2-DP 5）、15.95 g乙醇和1.44 g木糖醇。目前的研究报告了一种通过同时使用本土生产的真菌酶最大限度地利用纤维素和半纤维素部分，将 SCB 有效生物转化为增值产品的综合过程。