Tuesday, May 3, 2011
Recent technological and agronomical investigations have pointed out many plants as possible sources of 2nd generation bioethanol and, in Europe, the giant reed (Arundo donax L.) has been selected as one of the more interesting. This perennial species has high mass productivity, contains about 40% of cellulose, is very hardy and does not need fertilizers nor herbicides during growth. In this work we report data about the enzymatic saccharification of Arundo donax by cocktails of commercial and/or innovative thermostable enzymes optimizing the biomass pretreatment and the hydrolytic process conditions. To increase the saccharification yield the biomass has been subjected to a steam explosion pretreatment at 210 °C for 10 min in a 10 L batch reactor. The exploded substrate was recovered with a 91% yield, and washed with hot water to separate the soluble hemicellulose and degradation products from the insoluble residue. The pretreated material, having a cellulose content of 51%, was hydrolyzed with mixtures of enzymes at different incubation times, pH and temperatures. The highest yield achieved for the conversion of glucan in glucose was 95% and was obtained on steam exploded biomass with a pool of cellulase and beta-glucosidase at 50°C and pH 5.0. Other pretreatments (acid and alkaline), and different concentrations of substrate and/or enzymes have been investigated and reported.