Microspectrophotometry applied to the study of lignocellulose recalcitrance

Abstract

The aim of this project is to study the topochemical distribution of lignin and hydroxycinnamic acids in the cell walls of lignocelulosic materials. Modem methods will be developed to determine lignin structural characteristics and localization in cell walls using UV - microspectrophotometric techniques. The technique is based on the use of an especially designed optical microscope able to work in the UV spectral wavelengths (Zeiss/J&M). The microscopic technique will also permit to map lignin and hydroxycinnamic acids in pre-defined areas of the cellular complex by means of an automatic scanning stage device. The lignocellulosic materials to be studied include several sugar cane samples selected to cover commercial varieties and experimental hybrids containing varied concentrations of lignin and extractives. Samples with reduced lignin contents will be also prepared by selective delignification procedures. In all cases, the samples will be digested by a mixture of commercial cellulases aiming to correlate the recalcitrance of sugar cane cell walls with their lignin and hydroxycinnamic acid contents as well as their topochemical distribution. (AU)