Pretreatment strategies for delignification of sugarcane bagasse: a review

Abstract

The valorization of agro-residues by biological routes is a key technology that contributes to the development of sustainable processes and the generation of value-added products. Sugarcane bagasse is an agro-residue generated by the sugar and alcohol industry in Brazil (186 million tons per year), composed essentially of cellulose (32-44%), hemicellulose (27-32%) and lignin (19-24%). The conversion of sugarcane bagasse into fermentable sugars requires essentially two steps: pretreatment and hydrolysis. The aim of the pretreatment is to separate the lignin and break the structure of lignocellulose, and it is one of the most critical steps in the process

Isolation and characterization of a novel Penicillium oxalicum strain Z1-3 with enhanced cellobiohydrolase production using cellulase-hydrolyzed sugarcane bagasse as carbon source

“…Importantly, during cellulose saccharification, the conversion is often limited to 80-90% due to the recalcitrance of biomass residues to enzymatic hydrolysis (Karp et al, 2013;Van Dyk and Pletschke, 2012). Few studies have designed schemes to increase the conversion rate of such biomass residues.…”

“…Previously, studies showed that plant species and/or varieties affected the pretreatment applications, resulting in a wide range of enzymatic hydrolysis efficiencies (Huang et al, 2015;Kumar et al, 2013;Li et al, 2014). Similarly, the conversion of SB into single sugars also cannot satisfactorily reach 100% as a result of the recalcitrance of the residues to enzymatic hydrolysis (Karp et al, 2013). Therefore, it is necessary to design an experiment to screen, based on specific substrates such as cellulolytic enzyme-hydrolyzed sugarcane bagasse residues (SBRs) as carbon source, for potential fungal strains that efficiently produce cellulolytic enzymes.…”

Chemical characteristics and enzymatic saccharification of lignocellulosic biomass treated using high-temperature saturated steam: Comparison of softwood and hardwood

“…However, because cellulosic components (i.e., substrates for ethanol production) are strongly covered with lignin in the lignocellulosic biomass, pretreatment (delignification) is necessary for efficient enzymatic saccharification followed by alcohol fermentation to increase the accessibility of cellulose to cellulases (Karp et al, 2013). Various pretreatment methods have been developed and applied to target the conversion of biomass to biofuel including: acid treatment (Torget et al, 1988), alkaline treatment (Ucar, 1990), ammonia fiber expansion (Dale et al, 1996), organosolv treatment (Bonn et al, 1987), liquid hot water treatment (Sreenath et al, 1999), microwave irradiation (Ooshima et al, 1984), superheated steam treatment (Bahrin et al, 2012), and steam explosion (Ramos et al, 1992).…”

Production of extra cellular enzymes by microbial strains in molasses and additives supplemented fermentation media

“…The growing demand for lower cost in industrial processes that are also highly specific and environmentally safe has stimulated the search for new enzymes. The use of agro-industrial residues in bioprocesses has enabled the production of enzymes employing alternative substrates at low cost as well as reducing environmental degradation caused by the disposal of these residues (Elisashvili et al, 2008;Karp et al, 2013).…”