Enhanced Enzymatic Saccharification of Mixed Sawdust Wastes: Comparison of SPORL, Dilute Acid, Formic Acid, and Ethanol Organosolv Pretreatments

Abstract. Utilization of the huge quantity of sawdust wastes is urgent. In this study, SPORL, dilute acid pretreatment (DA), formic acid pretreatment (FA), ethanol pretreatment (EtOH/H2O), and sulfuric acid catalyzed ethanol pretreatment (EtOH/H2O/H2SO4), on improving enzymatic hydrolysis of mixed sawdust wastes were comprehensively compared. EtOH/H2O/H2SO4 was the most effective pretreatment in lignin removal from sawdust fiber cell wall, while FA was much more effective in hemicellulose removal. After the pretreatments, the crystallinity of cellulose increased because of the removal of amorphous hemicellulose and lignin. Moreover, the fiber surface became coarse and porous, especially after EtOH/H2O/H2SO4, the structure was destroyed into fragments, which enhanced the cellulase accessibility of cellulose. Therefore, the glucose yield of EtOH/H2O/H2SO4 pretreated substrate was highest among these five pretreatments, achieved at 91.4% with a cellulase loading of only 10 FPU/g glucan. Resumen. Es urgente aprovechar la gran cantidad de residuos de aserrín. En este estudio, SPORL, pretratamiento con ácido diluido (DA), pretratamiento con ácido fórmico (FA), pretratamiento con etanol (EtOH/H2O) y pretratamiento con etanol catalizado con ácido sulfúrico (EtOH/H2O/H2SO4), sobre la mejora de la hidrólisis enzimática de residuos de aserrín mezclado fueron comparados de manera integral. EtOH/H2O/H2SO4 fue el pretratamiento más eficaz para eliminar la lignina de la pared celular de la fibra de aserrín, mientras que el FA fue mucho más eficaz para eliminar la hemicelulosa. Después de los pretratamientos, la cristalinidad de la celulosa aumentó debido a la eliminación de hemicelulosa amorfa y lignina. Además, la superficie de la fibra se volvió gruesa y porosa, especialmente después de EtOH/H2O/H2SO4, la estructura se destruyó en fragmentos, lo que mejoró la accesibilidad de celulasa de la celulosa. Por lo tanto, el rendimiento de glucosa del sustrato pretratado con EtOH/H2O/H2SO4 fue el más alto entre estos cinco pretratamientos, alcanzado al 91,4% con una carga de celulasa de solo 10 FPU / g de glucano.

Download Full-text

Role of hemicellulose removal during dilute acid pretreatment on the cellulose accessibility and enzymatic hydrolysis of compositionally diverse sugarcane hybrids

Industrial Crops and Products ◽

10.1016/j.indcrop.2017.11.053 ◽

2018 ◽

Vol 111 ◽

pp. 722-730 ◽

Cited By ~ 27

Author(s):

Victor Tabosa de Oliveira Santos ◽

Germano Siqueira ◽

Adriane Maria Ferreira Milagres ◽

André Ferraz

Keyword(s):

Enzymatic Hydrolysis ◽

Dilute Acid Pretreatment ◽

Dilute Acid ◽

Acid Pretreatment ◽

Cellulose Accessibility ◽

Hemicellulose Removal ◽

Sugarcane Hybrids ◽

Hydrolysis Of

Download Full-text

Investigation of interaction between cellulase and residual lignin fractions in acid-pretreated bamboo residues and their effect on enzymatic digestibility

10.21203/rs.3.rs-371092/v1 ◽

2021 ◽

Author(s):

Wenqian Lin ◽

Jinlai Yang ◽

Yayue Zheng ◽

Caoxing Huang ◽

Qiang Yong

Keyword(s):

Enzymatic Hydrolysis ◽

Negative Impact ◽

Interaction Mechanism ◽

Dilute Acid Pretreatment ◽

Affinity Constant ◽

Residual Lignin ◽

Dilute Acid ◽

Enzymatic Digestibility ◽

Acid Pretreatment ◽

Hydrolysis Of

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.

Download Full-text

Effect of Subsequent Dilute Acid and Enzymatic Hydrolysis on Reducing Sugar Production from Sugarcane Bagasse and Spent Citronella Biomass

Journal of Energy ◽

10.1155/2016/8506214 ◽

2016 ◽

Vol 2016 ◽

pp. 1-12 ◽

Cited By ~ 20

Author(s):

Robinson Timung ◽

Narendra Naik Deshavath ◽

Vaibhav V. Goud ◽

Venkata V. Dasu

Keyword(s):

Enzymatic Hydrolysis ◽

Sugarcane Bagasse ◽

Crystallinity Index ◽

Sem Analysis ◽

Reducing Sugar ◽

Dilute Acid Pretreatment ◽

Crystalline Cellulose ◽

Dilute Acid ◽

Acid Pretreatment ◽

Hydrolysis Of

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.

Download Full-text