Generation of fermentable sugars from Eucalyptus sp. sawdust treated with white rot fungi

RODRIGUEZ, MD; CASTRILLO, ML; KRAMER, GR; VELAZQUEZ, JE; ZAPATA, PD; VILLALBA, LL

Iguazu

Simposio; Simposio Internacional de Materiales Lignocelulosicos; 2013

Cellulose is the main component of plant cell wall, the most abundant polymer on the earth and a major renewable resource. Rot fungi, for their enzymatic capacity, are excellence organisms capable of degrading lignocellulosic material. The cellulase enzyme system consists of three main enzymes (endoglucanases, exoglucanases y β-glucosidases), which act synergistically to degrade cellulose to glucose. One of these are endoglucanase, which acts on reducing ends of cellulose. The aim of the present work was assay the Eucalyptus sp. sawdust as a substrate for obtaining fungal endoglucanases, and determines appropriate conditions for cultivation. For this, was used two different genre strains of Basidiomycetes Phyllum: Phlebia sp. and Pycnoporus sp .. Inoculum was used as the disintegrated microorganism, which was added to the various assays. The culture media were composed by Czapeck -peptone and Eucaliptus sp sawdust, as unique carbon source. The variables studied were: two culture temperatures and three different conditions of liquid / solid ratio: 0.75, 9.75 and 18.75. All assays were performed in duplicate. The incubation time was 32 days, where a first wash was performed and then allowed incubate for 24 days more. The determination of enzymatic activity was performed by measuring reducing sugars as glucose at 32 and 56 days of incubation. As result, the activity values obtained in solid assays were higher than those reported by other authors in lignocellulosic substrates and SSF. However, the amounts were low, when compared with data obtained under induction conditions. There are not significant differences between the two culture temperatures. The most favorable conditions corresponded with the solid substrate assay using Phlebia sp.. In conclusion it can be reported that  the biotreatment of Eucalyptus sp. sawdust with white rot fungi can easily render simple fermentable sugars.  .