ABSTRACT
Lignocellulosic residues are abundant, renewable and inexpensive energy sources, and the increasing expansion of the agro-industrial sector has led to the accumulation of a large quantity of these residues from agricultural (e.g., sugarcane bagasse, corn stover, rice straw, wheat straw, barley straw and olive stones), forestry (e.g., sawdust, thinnings, and mill waste), herbaceous (e.g., switchgrass, coastal Bermuda grass and alfalfa hay), hardwood (aspen,
1IBB Institute for Biotechnology and Bioengineering, Center of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal. 2Department of Biology, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, 14040-901 Ribeirão Preto, SP, Brazil. 3Institute of Technology and Research, University Tiradentes, Campus Farolândia, 49032-490 Aracaju, SE, Brazil. 4Federal University of Sergipe, Nucleus of Production Engineering NPR/UFS, São CristovãoSE, 49100-000, Brazil. *Corresponding author: mimichelin.bio@gmail.com
poplar), softwood (pine, spruce), municipal solid wastes (e.g., waste paper) and various industrial wastes all over the world (Sánchez 2009). It is worth noting that crop residues encompass all agricultural wastes such as straw, husk, shell, peel, stem, stalk, leaves, seed and others.
