Tuesday, April 30, 2013
Exhibit Hall
In this work, the ethanol production by Kluyveromyces marxianus NRRL Y-6860 and Saccharomyces cerevisiae in simultaneous saccharification and fermentation (SSF) from rice straw cellulignin (RSC) was evaluated at 30 and 45 °C. The cellulignin was obtained after dilute acid pre-treatment (100 mg H2SO4/g dry matter) at 120 °C for 30 min. SSF experiments were carried out in 125-mL Erlenmeyer flasks, containing 8 % (m/v) of RSC, enzyme loading of 25 FPU (Cellubrix) and 25 UI (Novozyme 188) for each gram of dry RSC, at 100 rpm. The highest ethanol volumetric productivity (QP) and ethanol yield from the potential glucose (YP/S) were obtained with K. marxianus at 45oC. On the other hand, S. cerevisiae did not show this same behavior, since higher YP/S value was attained at 30 °C, whereas QP was higher at 45oC. Under the evaluated conditions, the best results of ethanol yield from the potential glucose (YP/S) and the ethanol volumetric productivity (QP) were, respectively, 0.24 g/g and 2.69 g/L.h for K. marxianus at 45oC and 0.22 g/g at 30oC and 0.52 g/L.h at 45oC for S. cerevisiae. Based on the experimental results, it can be concluded that K. marxianus NRRL Y-6860 represents a potential microorganism for application on ethanol production from lignocellulosic materials in SSF process due to its high fermentative ability at elevated temperatures.
Supported by FAPESP, CNPq and CAPES (BRAZIL)