Investigation of alkaline hydrogen peroxide pretreatment and Tween 80 to enhance enzymatic hydrolysis of sugarcane bagasse

Abstract

Background Due to the intact structure of lignocellulosic biomass, pretreatment was a prerequisite to improve the enzymatic hydrolysis by disrupting the recalcitrant lignocellulose and increasing the accessibility of cellulose to enzyme. In this study, an alkaline hydrogen peroxide (AHP) pretreatment of sugarcane bagasse with various loadings of H 2 O 2 (1.25–6.25 wt%) at temperatures of 60–160 °C was proposed to degrade hemicellulose/lignin and improve the enzymatic digestibility. Results It was found that increasing H 2 O 2 loadings during pretreatment lead to the enhancement of substrate digestibility, whereas the alkali (only NaOH)-pretreated solid generated higher glucose yield than that pretreated under AHP pretreatment with lower loading of H 2 O 2 . This enhancement of enzymatic digestibility was due to the degradation of hemicellulose and lignin. Furthermore, Tween 80 was added to promote enzymatic digestibility, however, the increased yields were different with various substrates and hydrolysis time. The highest glucose yield of 77.6% was obtained after pretreatment at 160 °C for 60 min with 6.25% H 2 O 2 and the addition of Tween 80, representing 89.1% of glucose in pretreated substrate. Conclusions This study demonstrated that the AHP pretreatment could greatly enhance the enzymatic saccharification. The addition of Tween 80 played remarkable performances in promoting the glucose yield during enzymatic hydrolysis by stabilizing and protecting the enzyme activity. This study provided an economical feasible and gradual process for the generation of glucose, which will be subsequently converted to bioethanol and bio-chemicals. Electronic supplementary material The online version of this article (10.1186/s13068-019-1454-3) contains supplementary material, which is available to authorized users.

Evaluation of Pretreatment Methods (Acid and Alkali) in Improving the Enzymatic Saccharification of Sugarcane Baggase: Structural and Chemical Analysis

“…However, peak disappear at 1,324, 1,514 and 1604 cm − 1 when bagasse subjected to alkali pretreatment was deligni ed more e ciently in comparison with the acid pretreatments and un-treated sugarcane bagasse. Chandel et al, [14] and Zhang et al, [32] also reported similar results for sugarcane bagasse.…”

“…Thus, one of the objectives of the pretreatment is to increase the porosity and available surface area for the enzymatic attack [51,43,32]. The morphological investigation in the present study showed a signi cant increase in the porosity and surface area after the pretreatment, thus contribute to the enhancement of subsequent enzymatic hydrolysis [37,43,32].…”

“…In other words, this sharp decrease in crystallinity due to the alkali pretreatment con rms that the regenerated products were highly amorphous and thus, cellulose surface accessibility and consequently the e ciency of enzymatic hydrolysis were considerably increased [12,45,41,43]. Figures (3a) clearly indicates that the untreated bagasse had highly compact, ordered and rigid bril morphology [32] when compare with acid and alkali pretreated bagasse samples ( Fig. 3b-e).…”

“…For instance, at 897 cm − 1 , the peak obtained was more intense in cases of acid-pretreated sugarcane bagasase compared with untreated and alkali-pretreated sample. In the presence of amorphous cellulose, the band at 897 cm − 1 , which characterizes the C-O-C stretching at β-1,4-glycosidic linkage, is strong and sharp [31,32]. The intensity of the regenerated cellulose band is relatively stronger than that of the original cellulose.…”

Assessment of a novel pretreatment techniques for enhancing the enzymatic saccharification of sugarcane baggase: Structural and chemical analysis

“…For instance, at 897 cm -1 , the peak obtained was more intense in cases of acid pretreated sugarcane bagasse compared with untreated and alkali-pretreated sugarcane bagasse. In the presence of amorphous cellulose, the band at 897 cm -1 , which characterizes the C-O-C stretching at β-1,4glycosidic linkage, is strong and sharp [44][45]17]. The intensity of the regenerated cellulose band is relatively stronger than that of the original cellulose.…”