Estudo da recalcitrância da biomassa derivada de cana-deaçúcar por técnicas avançadas de imagem

Abstract

The search for new renewable sources has been motivating research in order to overcome the scarcity of fossil fuels, and the use of lignocellulosic materials, such as sugarcane bagasse, has been gaining prominence since, from it, it is possible to obtain the second generation ethanol. These materials are basically composed of cellulose, hemicellulose and lignin. The cellulose present in the material is encapsulated by complex bonds between hemicellulose and lignin that make it difficult for enzymes to access cellulose microfibrils. One of the barriers that makes using this material for the production of ethanol second generation is its recalcitrance, which is linked to the resistance that the vegetable has against the attacks of microorganisms from sugars inside the cell walls. This work aims to study the recalcitrance of biomass derived from sugarcane by advanced imaging techniques. Sugarcane bagasse, in natura and submitted to acid pretreatment (diluted solution of 1% H2SO4) and pre-treated alkaline (dilute solution of NaOH 1%) were characterized, assisted by microwave, at temperatures 130 ° C and 160 ° C for 30 minutes. The biomass samples were analyzed by characterization techniques such as Scanning Electron Microscopy (SEM) that provided information on morphological heterogeneity through sugarcane substrates, Electron Transmission Electron Microscopy (TEM) provided information on cell walls, Microscopy (XRD) that quantified the amount of crystalline cellulose present in lignocellulosic materials, Spectroscopy in the Infrared Region with Fourier Transform (FTIR) provided qualitative information on the chemical changes in sugarcane bagasse and Phase Contrast X-ray Tomography (TCF) provided information on the tissue architecture of sugarcane bagasse as well as the mapping of the lignin distribution