13-16: Enzymatic hydrolysis and fermentation of sugarcane bagasse after the electron beam and hydrothermal pretreatments

Monday, April 29, 2013
Exhibit Hall
Antonio J. G. Cruz1, Manoel N. Mori2, Luciano J. Correa3, Renata B. A. Souza3, Raquel L. C. Giordano4 and Celina L. Duarte5, (1)Chemical Engineering, Universidade Federal de São Carlos (UFSCar), São Carlos, Brazil, (2)Radiation technology Center, Institute for Nuclear and Energetic Research - IPEN, Sao Paulo, Brazil, (3)Laboratório de Desenvolvimento e Automação de Bioprocessos (LaDABio) – Depto. Eng. Química, Universidade Federal de São Carlos (UFSCar), São Carlos, Brazil, (4)Chemical Engineering Department, Federal University of Sao Carlos, Sao Carlos, Brazil, (5)Radiation Technology Center, Institute for Nuclear and Energetic Research - IPEN, Sao Paulo, Brazil
This study presents the evaluation of enzymatic hydrolyses and fermentations of sugarcane bagasse after electron beam processing, followed by hydrothermal pretreatment. The reactive species generated by the interaction of ionizing radiation with water (oxidant OH radical, reductants e-aq, and H radical)  can modify the structure of biomass making cellulose more accessible to conversion  the carbohydrate polymers into fermentable sugars. Sugarcane bagasse was irradiated using a Radiation Dynamics Electron Beam Accelerator with 1.5 MeV and 37 kW, in batch systems at 30 kGy and 50 kGy absorbed doses. The pretreated biomass was then submitted to thermal hydrolysis for 10 minutes at 190⁰C, 200 rpm, with a solid-liquid ration of 1:10 m/v (Parr reactor). The compositional analyses of the samples were run after each step (NREL standard method). The enzymatic assays were carried out with 10 % of solid loading (m/v) in 0.05 M sodium citrate buffer, 250 rpm, pH 4.8, at 50°C. A commercial cellulolytic enzyme preparation (Cellic CTec-2, Novozymes) with 10 FPU/g of dry biomass was used. Experimental results showed an increasing in cellulose conversion for samples that were subjected to irradiation when compared to the hydrothermal pretreated only. It was obtained 53.3%, 74.9% and 63.2% of glucose conversion (in 48h) for hydrothermal, 30 kGy and 50 kGy, respectively. Fermentation assays using glucose (test experiment) and the resulting sugar syrups were conducted in shake flasks (S. cerevisiae, 200 rpm, 30oC). The yield obtained ranges from 60 to 72% of the theoretical yield.