Investigation On Sulfuric Acid Pretreatment And Enzymatic Hydrolysis Of Sugarcane Bagasse

China is the world’s third largest country in the sugar cane production. As the leftovers of the sugar industry, bagasse is also a kind of renewable biomass resources. In order to overcome the “biomass recalcitrance”, pretreatment methods have been applied. Due to the advantages of low cost, high reactivity and stability, dilute sulphuric acid pretreatment method is suitable for industrial application with application prospect. In this paper, dilute sulfuric acid pretreatment conditions and mechanism of bagasse has been studied in a systematic way.The composition content of the bagasse of 20-40 mesh size mainly used in this experiment are as follows: glucan 50.99±1.19%, xylan 25.39±0.89%, Klason lignin 20.03±0.66%, acid-soluble lignin 0.29±0.15%. Through the orthogonal design and single factor experiments, the optimum pretreatment conditions got are as follows:160 ℃, H2SO4 concentration 0.8%, 15 min, solid-liquid ratio 1:15. In this condition, the total reducing sugar yield was 60.1%, among which the reducing sugar yield was 30.4%(including 26.5% xylose yield) after pretreatment, 29.6%(including 29.4% glucose yield) after enzyme hydrolysis. The furfural conversion rate was 0.85% after pretreatment.Under the optimal pretreatment conditions, further study about the effect of the bagasse size, cellulose crystallinity and lignin content on the enzyme hydrolysis rate was processed. Results show that within a certain range, reducing the size does not improve reducing sugar yield. While the high content of Klason lignin in the enzyme substrates may be the main reason. Higher crystallinity of the enzyme substrate didn’t lead to lower enzyme hydrolysis rate, due to the influence of other enzyme substrate features. The optimal size of raw bagasse in this experiment was 10-20 mesh, during which the total reducing sugar yield was 61.5%, including 31.3% after pretreatment and 30.2% after enzyme hydrolysis.In the optimal conditions above, the optimum enzyme hydrolysis parameters were studied and obtained as follows: enzyme dosage 40FPU/g, substrate concentration 5%, reaction temperature 50℃, reaction time 24 h. The reducing sugar conversion rate obtained during enzyme hydrolysis was 51.4%, while the sugar concentration was 15.87g/L. Due to the reducing sugar conversion rate after the pretreatment was 31.3%, the maximum total reducing sugar conversion rate was 82.7% in the optimal conditions of pretreatment and enzyme hydrolysis.