Chemical and bioenergetic characterization of sorghum agronomic groups1

Abstract

ABSTRACT The global demand and production of primary energy is expected to grow at a rate of 1.4 % per year by 2035. In the same period, the production of renewable energy is expected to grow at a rate of 6.6 % per year, rising from 3 % to 9 % of world primary energy. Therefore, the biofuels supply assumes a strategic role for world energy security. In this context, sorghum is a promising alternative in the bioenergetic sector, due to its agronomic characteristics and adaptability to limiting edaphoclimatic conditions. This study aimed at evaluating the productive potential of three sorghum agronomic groups (biomass, saccharin and forage), as well as chemically characterizing the biomass of these materials. For that, a field experiment was carried out using a randomized block design, where agronomic and chemical characteristics (cellulose, hemicellulose, lignin and ash), as well as moisture contents, were evaluated. The biomass sorghum cultivars presented a high yield (about 30 t ha-1 of dry stalk), being, for this reason, more suitable for the generation of solid biofuels, i.e., direct burning. On the other hand, the forage sorghum cultivars presented a lower lignin content in the stalks, in relation to the other cultivars, being indicated for the generation of liquid biofuels. It is also worth mentioning the possibility of producing second-generation bioethanol from saccharin sorghum bagasse. Therefore, sorghum presents different use potentials that may be exploited by the bioenergy sector according to the agronomic group and plant physical part.