scholarly journals Microwave-assisted Dilute Acid Pretreatment and Enzymatic Hydrolysis of Sago Palm Bark

BioResources ◽  
2016 ◽  
Vol 11 (3) ◽  
Author(s):  
Saleem Ethaib ◽  
Rozita Omar ◽  
Mustapa Kamal Siti Mazlina ◽  
Awang Biak Dayang Radiah ◽  
Syams Syafiie
2021 ◽  
Author(s):  
Wenqian Lin ◽  
Jinlai Yang ◽  
Yayue Zheng ◽  
Caoxing Huang ◽  
Qiang Yong

Abstract Background: During dilute acid pretreatment, pseudo lignin and lignin form droplets which deposit on the surface of lignocellulose, and further inhibit its enzymatic hydrolysis. However, how this lignin interacts with cellulase enzymes and then affects enzymatic hydrolysis is still unknown. In this work, different fractions of surface lignin (SL) obtained from dilute acid pretreated bamboo residues (DAP-BR) were extracted by various organic reagents and the residual lignin in extracted DAP-BR was obtained by milled wood lignin (MWL) method. All the obtained lignin fractions from DAP-BR were used to investigate the interaction mechanism between lignin and cellulase using surface plasmon resonance (SPR) technology in order to understand how they affect enzymatic hydrolysisResults: Results showed that removing surface lignin significantly decrease the enzymatic hydrolysis of DAP-BR from 36.5% to 18.6%. The addition of MWL samples to Avicel decreased enzymatic hydrolysis of Avicel, while different SL samples showed a slight increase to its enzymatic digestibility. Due to the higher molecular weight and hydrophobicity of MWL samples versus the SL samples, stronger affinity for MWL (KD = 6.8-24.7 nM) was found versus that of SL (KD = 39.4-52.6 nM) by SPR analysis. The affinity constant of all tested lignin had good correlations (R2>0.6) with their effects on enzymatic digestibility of extracted DAP-BR and Avicel.Conclusions: This work reveals that the surface lignin on DAP-BR is necessary towards maintaining enzyme digestibility levels, and its removal has a negative impact on the substrate’s digestibility.


2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Robinson Timung ◽  
Narendra Naik Deshavath ◽  
Vaibhav V. Goud ◽  
Venkata V. Dasu

This work was aimed at investigating the effect of process parameters on dilute acid pretreatment and enzymatic hydrolysis of spent citronella biomass (after citronella oil extraction) and sugarcane bagasse on total reducing sugar (TRS) yield. In acid pretreatment, the parameters studied were acid concentration, temperature, and time. At the optimized condition (0.1 M H2SO4, 120°C, and 120 min), maximum TRS obtained was 452.27 mg·g−1and 487.50 mg·g−1for bagasse and citronella, respectively. Enzymatic hydrolysis of the pretreated biomass usingTrichoderma reesei26291 showed maximum TRS yield of 226.99 mg·g−1for citronella and 282.85 mg·g−1for bagasse at 10 FPU, 50°C, and 48 hr. The maximum crystallinity index (CI) of bagasse and citronella after acid pretreatment obtained from X-ray diffraction analysis was 64.41% and 56.18%, respectively. Decreased CI after enzymatic hydrolysis process to 37.28% and 34.16% for bagasse and citronella, respectively, revealed effective conversion of crystalline cellulose to glucose. SEM analysis of the untreated and treated biomass revealed significant hydrolysis of holocellulose and disruption of lignin.


2006 ◽  
Author(s):  
Yi Zhenga ◽  
Zhongli Pana ◽  
Ruihong Zhanga ◽  
Donghai Wangc ◽  
John Labavitchd ◽  
...  

2012 ◽  
Vol 503-504 ◽  
pp. 190-193
Author(s):  
Jing Jing Zhao ◽  
Hai Yan Yang ◽  
Bo Li ◽  
Fu Ming Chen

Sulfite pretreatment was explored in enzymatic hydrolysis of bagasse for the first time, and was compared with dilute acid pretreatment. The results showed that enzymatic hydrolysis yield of bagasse after sulfite treatment was lower than that of the bagasse pretreated with dilute acid. Meanwhile, complexity of sulfite pretreatment and its high cost made it infeasible for industrialized production. Results also showed positive correlation of bagasse pretreatment weight loss to enzymatic hydrolysis yield in dilute acid pretreatment processes, which made substrate weight loss a plausible parameter in pretreatment evaluation.


Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 195 ◽  
Author(s):  
Manuel Cuevas ◽  
Marwa Saleh ◽  
Juan F. García-Martín ◽  
Sebastián Sánchez

Olive stones are an abundant lignocellulose material in the countries of the Mediterranean basin that could be transformed to bioethanol by biochemical pathways. In this work, olive stones were subjected to fractionation by means of a high-temperature dilute-acid pretreatment followed by enzymatic hydrolysis of the pretreated solids. The hydrolysates obtained in these steps were separately subjected to fermentation with the yeast Pachysolen tannophilus ATCC 32691. Response surface methodology with two independent variables (temperature and reaction time) was applied for optimizing D-xylose production from the raw material by dilute acid pretreatment with 0.01 M sulfuric acid. The highest D-xylose yield in the liquid fraction was obtained in the pretreatment at 201 °C for 5.2 min. The inclusion of a detoxification step of the acid prehydrolysate, by vacuum distillation, allowed the fermentation of the sugars into ethanol and xylitol. The enzymatic hydrolysis of the pretreated solids was solely effective when using high enzyme loadings, thus leading to easily fermentable hydrolysates into ethanol. The mass macroscopic balances of the overall process illustrated that the amount of inoculum used in the fermentation of the acid prehydrolysates strongly affected the ethanol and xylitol yields.


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