Chemical and morphological characterization of sugar cane bagasse

The sugar cane industry in Brazil is expanding, leading to great interest in using the leftover bagasse for other uses, beyond burning it for its energy. A thorough physical and chemical characterization of bagasse, particularly regarding its lignin structure, is relevant for a more rational utilization of the bagasse in the production of printing and writing pulp grades, dissolving pulp, ethanol, and power. The main goals of this study were characterizing the chemical (pith and fibers fractions) and morphologic (fibers fraction) properties of the sugar cane bagasse and the structure of the depithed bagasse lignin by two-dimensional nuclear magnetic resonance spectroscopy. Industrial whole bagasse was separated into two fractions: pith and depithed bagasse. The pith was only characterized chemically. The depithed bagasse was chemically and morphologically characterized. The cellulose, hemicelluloses, and lignin contents of the two materials varied significantly. The lignin composition of the depithed bagasse showed very high contents of phenolic cinnamic acids (PCAs). The depithed bagasse lignin presented fractions with different structural monomer distributions. The morphological analyses of the depithed bagasse indicated a short fiber material, similar to hardwoods.