Fungal pretreatment: An alternative in second-generation ethanol from wheat straw

7 páginas, 3 figuras, 2 tablas -- PAGS nros. 7500-7506The potential of a fungal pretreatment combined with a mild alkali treatment to replace or complement current physico-chemical methods for ethanol production from wheat straw has been investigated. Changes in substrate composition, secretion of ligninolytic enzymes, enzymatic hydrolysis efficiency and ethanol yield after 7, 14 and 21 days of solid-state fermentation were evaluated. Most fungi degraded lignin with variable selectivity degrees, although only eight of them improved sugar recovery compared to untreated samples. Glucose yield after 21 days of pretreatment with Poria subvermispora and Irpex lacteus reached 69% and 66% of cellulose available in the wheat straw, respectively, with an ethanol yield of 62% in both cases. Conversions from glucose to ethanol reached around 90%, showing that no inhibitors were generated during this pretreatment. No close correlations were found between ligninolytic enzymes production and sugar yieldsThis work was supported mainly by the CENIT I+DEA project (funded by CDTI, Spain) and carried out in collaboration with Abengoa Bionergía Nuevas Tecnologías. Authors thank also the Galician government (I. Barreto program), DEMO-2 and Lignodeco EU projects for additional supports, and Novozymes for providing commercial enzymes. D.S. thanks a FPU fellowship from the MICINNPeer reviewe