Productive potential and quality of rice husk and straw for biorefineries

The use of lignocellulosic biomass to obtain high value-added products and biofuels has been highlighted in the last years, introducing the biorefinery concept. Among the types of lignocellulosics that can be used in biorefineries, there are rice husk and rice straw, byproducts of rice production usually treated as waste. Every year, 650-975 million tons of rice straw and 800 million tons of rice husk are generated during cultivation and processing of rice. This paper accomplishes a review of potential utilization of rice husk and rice straw in biorefineries approaching its chemical, biochemical, and thermochemical conversions in biofuels, biomaterials, biochemicals, bioenergy, and other high value-added products. The composition of lignocellulosic biomass, as well as the intra and intermolecular interactions among cellulose, hemicelluloses, and lignin in the biomass structure responsible for its recalcitrant characteristics are discussed. The need of performing a pretreatment prior to bioconversion due to biomass recalcitrance and different possible bioconversion processes are approached.