Enhancing enzymatic saccharification of sugarcane bagasse by combinatorial pretreatment and Tween 80

Abstract

BackgroundThe recalcitrant structure of lignocellulosic biomass made it challenging for their bioconversion into biofuels and biochemicals. Pretreatment was required to deconstruct the intact structure by the removal of hemicellulose/lignin, improving the cellulose accessibility of enzyme. Combinatorial pretreatments with liquid hot water/H2SO4 and ethanol/NaOH of sugarcane bagasse were developed to improve enzymatic hydrolysis under mild conditions.ResultsAfter one-step 60% ethanol containing 0.5% NaOH pretreatment with solid to liquid ratio of 1/10, the glucose yield after hydrolysis for 72 h with enzyme dosage of 20 FPU/g substrate was enhanced by 41% and 205% compared to that of NaOH or 60% ethanol pretreated solids, respectively. This improvement was correlated with the removal of hemicellulose and lignin. However, using combinatorial pretreatments with 1% H2SO4 followed by 60% ethanol containing 0.5% NaOH, the highest glucose yield with Tween 80 reached 76%, representing 84.5% of theoretical glucose in pretreated substrate. While retaining similar glucose yield, the addition of Tween 80 capacitated either a reduction of enzyme loading by 50% or shortening hydrolysis time to 24 h. However, the enhancement with the addition of Tween 80 decreased as hydrolysis time was extended.ConclusionsThis study demonstrated that a combinatorial pretreatment with 1% H2SO4 followed by 60% ethanol containing 0.5% NaOH had significant effects on improving the enzymatic hydrolysis of sugarcane bagasse. The addition of Tween 80 enabled reducing the enzyme loading or shortening the hydrolysis time. This study provided an economically feasible and mild process for the generation of glucose, which will be subsequently converted to bioethanol and biochemicals.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1313-7) contains supplementary material, which is available to authorized users.

Recent advances in understanding the effects of lignin structural characteristics on enzymatic hydrolysis

“…have also been reported that can decrease the non-productive adsorption of cellulase onto lignin. For example, Tween 80 and BSA could mitigate the unproductive adsorption of cellulase on lignin by binding with lignin, thus improving the access of enzymes to cellulose [ 10 , 11 ]. Lin et al [ 12 ] found that the addition of PEG could reduce the non-productive adsorption of cellulase onto lignin by forming the PEG–cellulase complex, which could disperse cellulase and avoid cellulase aggregation.…”

β‐Glucosidase produced by Moniliophthora perniciosa: Characterization and application in the hydrolysis of sugarcane bagasse

“…By delignifying the bagasse by a single step with 0.5% NaOH in ethanol, Zhang et al 47 . obtained a 17.9% removal of lignin.…”

“…By delignifying the bagasse by a single step with 0.5% NaOH in ethanol, Zhang et al 47 obtained a 17.9% removal of lignin. Lignin removal was more efficient in the alkaline and sulfite-alkaline treatments carried out by Siqueira et al, 27 with removal rates of 26.3% and 48.8%, respectively, after 60 min of reaction.…”

“…Siqueira et al 27 obtained a glucose yield of 82-92% after hydrolyzing the sugarcane bagasse delignified by sulfitealkaline pretreatment. Zhang et al 47 carried out enzymatic hydrolysis of sugarcane bagasse and obtained the highest glucose yields in the samples treated with 0.5% NaOH solu-F I G U R E 5 Pareto chart for optimization of the hydrolysis of delignified sugarcane bagasse tion in ethanol, with 72% of glucose after 72 h of hydrolysis. Monte et al 45 compared the efficiency of sulfite-acid and sulfite-alkaline pretreatments for sugarcane bagasse, obtaining a conversion of about 65% in the sulfite-alkaline pretreatment carried out with a 7.5% sulfite load.…”

Emerging Strategies for Modifying Lignin Chemistry to Enhance Biological Lignin Valorization

“…In the first phase, dilute acid (i. e., 1 % w/v H 2 SO 4 ) or hydrothermal pretreatment is applied to primarily remove hemicelluloses, extractives, ash, and other non‐structural compositions from biomass . In the second phase, dilute alkali (i. e., 1 % w/v NaOH) is employed to depolymerize and dissolve lignin into the liquid stream and thereby separating it from cellulose . As shown in Table , this combinatorial pretreatment increased glucose and xylose percent yield by 9.8 % and 8.1 %, respectively, compared with the single alkali pretreatment control.…”