Enhancement and modeling of enzymatic hydrolysis on cellulose from agave bagasse hydrothermally pretreated in a horizontal bioreactor

Abstract

A B S T R A C TOne of the major challenges in biofuels production from lignocellulosic biomass is the generation of high glucose titers from cellulose in the enzymatic hydrolysis stage of pretreated biomass to guarantee a cost-effective process. Therefore, the enzymatic saccharification on cellulose at high solid loading is an alternative. In this work, the agave bagasse was hydrothermally pretreated and optimized at 194°C/30 min, obtaining a pretreated solid rich in cellulose content (> 46.46%), and subjected to enzymatic hydrolysis at high solid levels. A horizontal bioreactor was designed for enzyme saccharification at high solid loadings [25% (w/v)]. The bioreactor improved mixing efficiency, with cellulose conversions up to 98% (195.6 g/L at 72 h). Moreover, mathematical modeling of cellulase deactivation demonstrated that cellulases lose most of their initial activity in the first hours of the reaction. Also, cellulose was characterized by X-ray diffraction, and the pretreated solids were visualized using scanning electron microscopy.

Engineering aspects of hydrothermal pretreatment: From batch to continuous operation, scale-up and pilot reactor under biorefinery concept

“…The degradation of cellulose at relatively high hydrothermal pretreatment severity has also been explored to understand its degradation behavior in deep (Pino et al, 2019). Normally, the crystalline cellulose is more difficult to be hydrolyzed than the amorphous cellulose.…”

“…In the process of the following enzymatic hydrolysis, the redeposited lignin hinders the accessibility of cellulase to cellulose via physical barrier and nonspecific adsorption of cellulase on the lignin. Thus, the pseudo-lignin and re-deposition of the formed lignin droplets significantly impact the cellulose hydrolysis (Selig et al, 2007;Ruiz et al, 2011a;Ruiz et al, 2012a;Hu et al, 2012;Pino et al, 2019).…”

Rapid mechanoenzymatic saccharification of lignocellulosic biomass without bulk water or chemical pre-treatment

“…Compared to conventional slurry or solution processes which require a harsh pre-treatment, RAging does not require any chemical pre-treatment, while leading to higher reaction rates (Tables S1, S2). 29,32,62,[54][55][56][57][58][59][60][61] In addition to providing the crude product with the highest reported monosaccharide concentration (second highest for glucose alone), the space-time yield (mass of sugar produced per litre of reaction per hour, see Tables S1 and S2) of our enzymatic RAging process is at least twice higher than that of any other reported method (Tables S1 and S2).…”

Enhancing biomass hydrolysis for biofuel production through hydrodynamic modeling and reactor design

“…Mechanical mixing is often used to study the HSEH operation for a range of lignocellulosic substrates. [5][6][7][8][9][10] The advantages of mechanical mixing are its flexibility and simplicity of operation, good control over parameters, and the wealth of experience associated with this unit operation. Biomass feeding methods, on the other hand, have the potential to manage the viscosity in the system, 5,6,11 and the two systems combined have been shown to enhance the overall conversion of sugars.…”

“…[5][6][7][8][9][10] The advantages of mechanical mixing are its flexibility and simplicity of operation, good control over parameters, and the wealth of experience associated with this unit operation. Mechanical mixing is often used to study the HSEH operation for a range of lignocellulosic substrates.…”