Enzyme recycling in a simultaneous and separate saccharification and fermentation of corn stover: A comparison between the effect of polymeric micelles of surfactants and polypeptides

Eckard, Anahita Dehkhoda; Muthukumarappan, Kasiviswanathan; Gibbons, William R.

doi:10.1016/j.biortech.2013.01.018

Cited by 31 publications

(20 citation statements)

References 32 publications

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“…According to Eckard et al [52], after two steps recycling of fermentation liquor containing enzymes, the ethanol yield was improved by 80% and 130% with the aid of Tween and liquid casein micelles, respectively. Polymeric micelles (PMs) of PEG-Tween and PEG-Casein improved enzyme recycling further, such that the ethanol yield was improved by 50% and 108% beyond that obtained with only Tween and casein, respectively.…”

Section: Impact Of Amphiphiles On Enzyme Recyclingmentioning

confidence: 99%

A Review of the Role of Amphiphiles in Biomass to Ethanol Conversion

2013

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Abstract:One of the concerns for economical production of ethanol from biomass is the large volume and high cost of the cellulolytic enzymes used to convert biomass into fermentable sugars. The presence of acetyl groups in hemicellulose and lignin in plant cell walls reduces accessibility of biomass to the enzymes and makes conversion a slow process. In addition to low enzyme accessibility, a rapid deactivation of cellulases during biomass hydrolysis can be another factor contributing to the low sugar recovery. As of now, the economical reduction in lignin content of the biomass is considered a bottleneck, and raises issues for several reasons. The presence of lignin in biomass reduces the swelling of cellulose fibrils and accessibility of enzyme to carbohydrate polymers. It also causes an irreversible adsorption of the cellulolytic enzymes that prevents effective enzyme activity and recycling. Amphiphiles, such as surfactants and proteins have been found to improve enzyme activity by several mechanisms of action that are not yet fully understood. Reduction in irreversible adsorption of enzyme to non-specific sites, reduction in viscosity of liquid and surface tension and consequently reduced contact of enzyme with air-liquid interface, and modifications in biomass chemical structure are some of the benefits derived from surface active molecules. Application of some of these amphiphiles could potentially reduce the capital and operating costs of bioethanol production by reducing fermentation time and the amount of enzyme used for saccharification of biomass. In this review article, the benefit of applying amphiphiles at various stages of ethanol production (i.e., OPEN ACCESSAppl. Sci. 2013, 3 397 pretreatment, hydrolysis and hydrolysis-fermentation) is reviewed and the proposed mechanisms of actions are described.

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Section: Impact Of Amphiphiles On Enzyme Recyclingmentioning

confidence: 99%

A Review of the Role of Amphiphiles in Biomass to Ethanol Conversion

2013

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“…However, the economics of enzymatic saccharification still remain a problem. After enzymatic saccharification, the enzymes are distributed within the liquid phase and solid lignocellulose (Pribowo et al 2012;Eckard et al 2013). The recovery and recycling of enzymes bound to the substrate and hydrolysate Japan).…”

Section: Introductionmentioning

confidence: 99%

Influence of High-Pressure Steam Pretreatment on the Structure of Rice Husk and Enzymatic Saccharification in a Two-Step System

et al. 2017

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This study aimed at developing an operational high-pressure steam pretreatment (HPSP) to effectively modify rice husk for enzymatic saccharification. The HPSP was performed at 160 to 200 °C under 0.3 to 2.8 MPa for 2 to 10 min. The efficiency of this method was based on the chemical composition, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD) analyses. Optimum pretreatment conditions (200 °C, 1.85 MPa for 7 min), enzyme concentration at 30 FPU/g and temperature at 60 °C for 48 h of continuous saccharification effectively produced sugar (21.1 g/L = 0.422 g/g dry substrate) at a saccharification degree of 53.87%. Conducting a secondstep enzymatic saccharification resulted in additional sugar production (7.9 g/L = 0.158 g/g substrate) and a 20.44% saccharification degree. In contrast, the two-step saccharification process (48 and 24 h) achieved optimal sugar yield of 0.581 g/g substrate and saccharification degree of 73.5%. Additionally, the process improved the yield of monomeric sugars of glucose (0.465 g/g), xylose (0.010 g/g), and cellobiose (0.063 g/g). Therefore, the combination of the high-pressure steam pretreatment with thermostable cellulase from Bacillus licheniformis 2D55 in a two-step enzymatic saccharification process is an economically viable method in rice husk bioprocessing for sugar production.

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“…After air drying, the cornstalks were cut into 5 cm to 10 cm sections and then treated by stream explosion at 1.7 MPa and 205 °C for 6 min. In the following fermentation process, the cellulose of the pretreated cornstalks was used as the raw material for conversion into bio-ethanol using the SSF (simultaneous saccharification and fermentation) method (Eckard et al 2013). Additionally, EHL was purified from ER using an alkali-solution and acid-isolation method (Guo et al 2013); all chemicals used were analytical-grade reagents.…”

Section: Experimental Materialsmentioning

confidence: 99%

Hydrothermal Degradation of Enzymatic Hydrolysis Lignin in Water-Isopropyl Alcohol Co-Solvent

Qiao

et al. 2016

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The effect of hydrothermal conditions on enzymatic hydrolysis lignin (EHL) degradation in water-isopropyl alcohol co-solvent and optimal conditions were investigated. The yields and reactivity toward formaldehyde of degraded enzymatic hydrolysis lignin (DEL) were determined. The optimal conditions of temperature, time, and ratio of solids to liquids were 250 °C, 60 min, and 1:10 (w/v), respectively. The EHL and DEL were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), 1 H nuclear magnetic resonance ( 1 H NMR), thermal gravity (TG), and differential scanning calorimetry (DSC) analyses. The results revealed that the molecular weight and polydispersity of DEL were lower than that of EHL. Although the fundamental structure of lignin before and after hydrothermal degradation was retained, the ether (β-O-4, α-O-4, etc.) content decreased, while that of hydroxyl (phenolic and aliphatic) increased. The DTGmax and Tg values shifted from 334 and 117 °C to 304 and 105 °C, respectively.

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Enzyme recycling in a simultaneous and separate saccharification and fermentation of corn stover: A comparison between the effect of polymeric micelles of surfactants and polypeptides

Cited by 31 publications

References 32 publications

A Review of the Role of Amphiphiles in Biomass to Ethanol Conversion

A Review of the Role of Amphiphiles in Biomass to Ethanol Conversion

Influence of High-Pressure Steam Pretreatment on the Structure of Rice Husk and Enzymatic Saccharification in a Two-Step System

Hydrothermal Degradation of Enzymatic Hydrolysis Lignin in Water-Isopropyl Alcohol Co-Solvent

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