Fractionation of sugarcane bagasse using hydrothermal and advanced oxidative pretreatments for bioethanol and biogas production in lignocellulose biorefineries

Pretreatment and enzymatic hydrolysis of coffee husk for the production of potentially fermentable sugars

“…The alkaline-extracted PCH solid fraction (experiment 6) after submitted to the AE step presented an EHY value of 32.6% ± 0.8%. This result was contrary to those reported by Wu et al, 65 who reported an increase of the EHY value from 36.0% to 83.0% for LHW pretreated wheat straw after AE step (0.2 mol L −1 NaOH solution) and Bittencourt et al, 42 who reported an increase of the EHY value from 34.6% to 46.8% for LHW pretreated sugarcane bagasse after AE step (0.2 mol L −1 NaOH solution).…”

“…Although the effect of an AE step was considered as positive for some pretreated biomasses, 42 for LHW pretreated CHs the effect of an AE step was not as effective as expected for the increase of the EHY value. The PCH solid fraction (experiment 6) presented an EHY value of 41.4% ± 0.3%.…”

“…The reactor vessel was loaded with NaOH (0.2 mol L −1 ) solution and PCHs to give a LSR of 10 mL g −1 . 42 At the end of the AE step, the solid fraction was washed under reduced pressure with distilled water until the washing water reached a neutral pH and then was stored at −4 °C in a freezer.…”

2-Hydroxy-1,4-naphthoquinone (Lawsone) as a Redox Catalyst for the Improvement of the Alkaline Pretreatment of Sugarcane Bagasse

“…Preservation of the carbohydrate fraction during the LB pretreatment is crucial for the viability of a biomass fractionation process to be implemented in a lignocellulose biorefinery. This allows maximization of added-value product generation, increasing process profitability . On the other hand, the pretreatment should be as selective as possible for removing lignin from solid fraction (LB) to liquid fraction (black liquor).…”

“…The effectiveness of a pretreatment step is based on reducing the degree of crystallinity ( X c ) and polymerization (DP) of polysaccharides, leading to an increase in enzyme accessibility to cellulose − without producing compounds that may inhibit the enzymatic hydrolysis and fermentation steps. , The major inhibitory compounds are (i) organic acids (acetic acid and formic acid) and furans (2-furfuraldehyde and 5-hydroxymethyl-2-furfuraldeyde) produced from hydrolysis of polysaccharides and degradation of C5 and C6 sugars, which interfere with yeast metabolism in the fermentation step and (ii) lignin fragments and lignin fragments condensed with furans, which may block the access of hydrolytic enzymes to cellulose and also promote unproductive adsorption of enzymes. , …”