Caracterização de genes lignocelulolíticos e produção de etanol de segunda geração

Abstract

Brazil is the largest producer of sugarcane in the world and produces up to tons per year, and each ton produces approximately 140 kg of bagasse in the process. Part of this bagasse is burned to generate electricity in power plants. The excess of this waste causes environmental and storage problems. Bagasse of sugarcane can be a raw material of second generation ethanol, due to its availability and lignocellulosic composition. The use of this residue needs to pre-treatment so that their structure need to be broken and the cellulose, hemicellulose and lignin are exposed to hydrolysis, and the sugars available for fermentation. lignocellulosic enzymes are the most efficient in degrading wood and lignocellulosic materials, among them: laccase, lignin peroxidase and manganese peroxidase, all produced by fungi basidiomycetes. This work aimed to verify the production of ethanol by wild yeast taken from ruminant animals and verify the genes of lignocellulosic enzymes of fungi basidiomycetes for the hydrolysis of sugarcane bagasse. To evaluate the fermentative capacity of the CBA-524 yeast and CBA-519 and Pichia stipitis, they were first inoculated in synthetic media containing D-xylose and D-glucose, and then hydrolyzed through sugarcane bagasse, produced by acid hydrolysis 1% H2SO4. The basidiomycete fungi Hexagonia glabra, Pycnoporus sanguineus, Trametes sp. and Pleurotus sp. had their lignocellulosic enzymes genes sequenced and compared in GenBank. The CBA-524 and CBA-519 yeasts were identified as Meyerozyma guilliermondii and Pichia kudriavzevii, respectively, they produced ethanol from sugarcane bagasse hydrolysate. The four fungi (Hexagonia glabra UEA, Pycnoporus sanguineus UEA, Trametes sp. UEA and Pleurotus sp. UEA) amplified the laccase gene, but with low similarity. The identified yeasts showed good production of second generation bioethanol.