Mathematical model of steady-state countercurrent bed-shrinking reactor in dilute acid

2021 ◽  
Vol 1 (2) ◽  
pp. 001-011
Author(s):  
Saranya Jaganathan ◽  
Rajendran Lakshmanan
Keyword(s):  
Mathematical Model ◽  
Nonlinear Differential Equations ◽  
Perturbation Technique ◽  
Dilute Acid Pretreatment ◽  
Rate Equations ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Dimensional Parameters ◽  
The Mathematical Model ◽  
Analytical Expressions

The mathematical model of bed-shrinking in a countercurrent reactor proposed by Lee (Bioresource Technology 71 (2000) 29 - 39) is explored. This model is based on system of nonlinear differential equations. Analytically, the coupled nonlinear rate equations are solved. To produce approximate analytical expressions for hemicelluloses, oligomers, and xylose concentrations for all the values of non-dimensional parameters and , the homotopy perturbation technique is applied. Our analytical results were compared to existing experimental data and found to be very similar. The dilute-acid pretreatment/hydrolysis of lignocellulosic biomass is studied using this mathematical model in the reactor.

scholarly journals Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Wenqian Lin ◽  
Jinlai Yang ◽  
Yayue Zheng ◽  
Caoxing Huang ◽  
Qiang Yong
Keyword(s):  
Enzymatic Hydrolysis ◽  
Negative Impact ◽  
Dilute Acid Pretreatment ◽  
Residual Lignin ◽  
Dilute Acid ◽  
Enzymatic Digestibility ◽  
Acid Pretreatment ◽  
Organic Reagents ◽  
Milled Wood Lignin ◽  
Affinity Constants

Abstract Background During the dilute acid pretreatment process, the resulting pseudo-lignin and lignin droplets deposited on the surface of lignocellulose and inhibit the enzymatic digestibility of cellulose in lignocellulose. However, how these lignins interact with cellulase enzymes and then affect 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 the milled wood lignin (MWL) method. All of the lignin fractions obtained from DAP-BR were used to investigate the mechanism for interaction between lignin and cellulase using surface plasmon resonance (SPR) technology to understand how they affect enzymatic hydrolysis Results The results showed that removing surface lignin significantly decreased the yield for enzymatic hydrolysis DAP-BR from 36.5% to 18.6%. The addition of MWL samples to Avicel inhibited its enzymatic hydrolysis, while different SL samples showed slight increases in enzymatic digestibility. Due to the higher molecular weight and hydrophobicity of MWL samples versus SL samples, a 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 constants of all tested lignins exhibited good correlations (r > 0.6) with the effects on enzymatic digestibility of extracted DAP-BR and Avicel. Conclusions This work revealed that the surface lignin on DAP-BR is necessary for maintaining enzyme digestibility levels, and its removal has a negative impact on substrate digestibility.

scholarly journals A Process Study of Lactic Acid Production from Phragmites australis Straw by a Thermophilic Bacillus coagulans Strain under Non-Sterilized Conditions

Processes ◽  
2018 ◽  
Vol 6 (10) ◽  
pp. 175 ◽  
Author(s):  
Yuming Zhang ◽  
Mengran Li ◽  
Tian Nie ◽  
Zhihua Ni
Keyword(s):  
Lactic Acid ◽  
Phragmites Australis ◽  
Lactic Acid Production ◽  
Scale Up ◽  
Bacillus Coagulans ◽  
Dilute Acid Pretreatment ◽  
Integrated Process ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Process Study

Phragmites australis straw (PAS) is an abundant and renewable wetland lignocellulose. Bacillus coagulans IPE22 is a robust thermophilic strain with pentose-utilizing capability and excellent resistance to growth inhibitors. This work is focused on the process study of lactic acid (LA) production from P. australis lignocellulose which has not been attempted previously. By virtue of thermophilic feature of strain IPE22, two fermentation processes (i.e., separated process and integrated process), were developed and compared under non-sterilized conditions. The integrated process combined dilute-acid pretreatment, hemicellulosic hydrolysates fermentation, and cellulose utilization. Sugars derived from hemicellulosic hydrolysates and cellulose enzymatic hydrolysis were efficiently fermented to LA in a single vessel. Using the integrated process, 41.06 g LA was produced from 100 g dry PAS. The established integrated process results in great savings in terms of time and labor, and the fermentation process under non-sterilized conditions is easy to scale up for economical production of lactic acid from PAS.

scholarly journals Hemicellulose–Cellulose Composites Reveal Differences in Cellulose Organization after Dilute Acid Pretreatment

2018 ◽  
Vol 20 (2) ◽  
pp. 893-903 ◽  
Author(s):  
Riddhi Shah ◽  
Shixin Huang ◽  
Sai Venkatesh Pingali ◽  
Daisuke Sawada ◽  
Yunqiao Pu ◽  
...  
Keyword(s):  
Dilute Acid Pretreatment ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Cellulose Composites

Dilute Acid Pretreatment of Softwoods Scientific Note

1998 ◽  
pp. 77-87 ◽  
Author(s):  
Q. A. Nguyen ◽  
M. P. Tucker ◽  
B. L. Boynton ◽  
F. A. Keller ◽  
D. J. Schell
Keyword(s):  
Dilute Acid Pretreatment ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Scientific Note
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