Lignocellulosic biomass from agro‐industrial residues in South America: current developments and perspectives

Abstract

South America is a pivotal supplier of agricultural commodities for a growing world population. This large-scale production generates a substantial amount of lignocellulosic residue. Inadequate disposal of this material can lead to putrefaction and leaching, and can attract insects and rodents. Solid residues can be treated by incineration or composting -both causing greenhouse gas emissions. Biotransformation of lignocellulosic residues into valuable products has been proposed as a more sophisticated alternative to burning. However, pretreatment steps are necessary to obtain fermentable sugars for biological or thermochemical transformation into value-added products. In this review, we noted trends in lignocellulosic biomass generation and potential uses, with special attention to the procedures necessary for the generation of fermented products and bio-oil. This survey pointed out that sugarcane bagasse, cereal straws, bananas, and oil-palm biomass can generate about 900 million tonnes of biomass by 2025. Based on production data from several researchers it was estimated that these raw materials have the potential for annual production of more than 550 million tonnes of fermentable sugars (i.e., glucose and xylose), 670 million tonnes of bio-oil, or 4000 TWh of thermal energy. We describe procedures and strategies for the conversion of these residues to produce higher value-added biomolecules and to promote more sustainable application of lignocellulosic biomass

Microorganisms and Enzymes Used in the Biological Pretreatment of the Substrate to Enhance Biogas Production: A Review

“…The molecules for lignin, cellulose, and hemicellulose are presented, as well as the three lignin monomers, coniferyl (G) alcohols, coumaryl (H) and sinapyl (S), and, with a detailed image of the crystalline cellulose. [45,46]).…”

“…Figure 1. Lignocellulosic biomass substrate structure, representing plant structure and lignin, cellulose, hemicellulose molecule and carbohydrate polymers and aromatic polymers of lignocellulosic biomass (adapted from[45,46]). …”

Characterization of β-mannanase extracted from a novel Streptomyces species Alg-S25 immobilized on chitosan nanoparticles

“…Lignocellulosic wastes have been generated via the forest and agricultural residues and during the processing of plant biomass in various industries, including pulp and papers, food and agriculture (extracts of coffee bean, copra meal, palm kernel, konjac gum) and timber (sawmills, furniture, plywood) [6,7]. Among the lignocellulosic wastes, agro-industrial residues have received special attention as the sustainable feedstocks for the biorefinery because of their abundance and cost-effectiveness [8][9][10]. Reports indicate that cellulose and hemicellulose constitute greater than 50% of the dry weight of agro-industrial wastes [10,11].…”

On the production cost of lignocellulose‐degrading enzymes

“…The microorganisms most commonly used for producing cellulases, in both industrial and academic settings, are filamentous fungi of the genus Trichoderma, particularly T. reesei. 7,8,11,45,46 Trichoderma fungi can secrete high levels of cellulase cocktails while using a variety of cellulosic materials as carbon sources, such as agri-food wastes, 47 streams from the pulp and paper industry, 48 and domestic wastewater. 49 In fact, substrate characteristics have been recognized as an important factor affecting not only enzyme titers but also the composition of the enzymatic cocktail produced by T. reesei, as recently reviewed.…”