Pre-treatment and enzymatic hydrolysis of sugar cane bagasse

Author(s)

Sandra Marcela Gómez Rueda

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
• Defense date: 2010-06-14

Examining board members

Rubens Maciel Filho; Carlos Eduardo Vaz Rossell; Charles Dayan Farias de Jesus

• Advisor: Rubens Maciel Filho; Aline Carvalho da Costa

Abstract

In this work the production of fermentable sugars from sugar cane bagasse pretreated with diluted sulfuric acid and phosphoric acid and delignified with NaOH was estudied. 23 Factorial designs were performed to evaluate the influence of pretreatment time (h), temperature (°C) and acid concentration (H2SO4 or H3PO4). After pretreatment bagasse was delignified for 1 hour at 100 ° C with 1% p/v NaOH. The results have shown that both pre-treatments can lead to high glucose yields at enzymatic hydrolysis. The best results for the pretreatment with phosphoric acid was when bagasse was pretreated at 140 ° C, 120 min and 0.5% p/v H3PO4. After delignification with NaOH and enzymatic hydrolysis with 15 FPU/g of cellulase and 7,5 CBU/g of ?-glicosidase, 367 mg glucose/g untreated bagasse were released, corresponding to a 88% yield. When sulfuric acid was used, the best results were obtained for pretreatment at 100°C, for 15 min and with 0,5%p/v of H2SO4. After delignification and hydrolysis at the same conditions used in the phosporic acid pretreatment, glucose release was of 380,6 mg glucose/g non pretreated bagasse, corresponding to a 92% yield. Due to the good results obtained using phosphoric acid and because pretreatment with this acid is less studied than with sulfuric acid, it was chosen for the posterior stages of the study. In this stage experimental assays were performed to determine the influence of cellulase and ?-glucosidase loads on glucose yield at hydrolysis. Bagasse was pretreated with diluted phosphoric acid at the best conditions, delignified with NaOH and hydrolysed with cellulase and ?-glucosidase loads varying according to a central composite factorial design. Yield of 97.17% was obtained with 30 FPU/g of cellulase and 25 CBU/g of ?- glucosidase. Yield of 95.10%, only a little lower, was obtained with 25.85 FPU/g of cellulase and 7.33 CBU/g of ?-glucosidase (AU)