Fundamentals of Biomass Pretreatment at High pH

Sierra, R.; Holtzapple, Mark T.; Piamonte, Natalia

doi:10.1002/9780470975831.ch8

Cited by 15 publications

(16 citation statements)

References 69 publications

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“…Ammonia is used in many methods, such as ammonia recycled percolation (ARP), aqueous ammonia soaking (AAS), and ammonia fiber explosion (AFEX). Alkaline pretreatment mainly entails delignification, which has three stages: initial, bulk, and terminal (residual) [ 30 , 31 ]. The initial stage occurs at low activation energy (61 kJ/mol) and temperature (<170 °C), where α-aryl ether and β-aryl ether bonds in phenolic units are cleaved rapidly.…”

Section: One-step Pretreatmentmentioning

confidence: 99%

Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass

Kim

Dien

2016

Biotechnol Biofuels

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Production of advanced biofuels from woody and herbaceous feedstocks is moving into commercialization. Biomass needs to be pretreated to overcome the physicochemical properties of biomass that hinder enzyme accessibility, impeding the conversion of the plant cell walls to fermentable sugars. Pretreatment also remains one of the most costly unit operations in the process and among the most critical because it is the source of chemicals that inhibit enzymes and microorganisms and largely determines enzyme loading and sugar yields. Pretreatments are categorized into hydrothermal (aqueous)/chemical, physical, and biological pretreatments, and the mechanistic details of which are briefly outlined in this review. To leverage the synergistic effects of different pretreatment methods, conducting two or more pretreatments consecutively has gained attention. Especially, combining hydrothermal/chemical pretreatment and mechanical refining, a type of physical pretreatment, has the potential to be applied to an industrial plant. Here, the effects of the combined pretreatment (combined hydrothermal/chemical pretreatment and mechanical refining) on energy consumption, physical structure, sugar yields, and enzyme dosage are summarized.

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Section: One-step Pretreatmentmentioning

confidence: 99%

Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass

Kim

Dien

2016

Biotechnol Biofuels

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“…In order to assess the best pretreatment condition, two lime (Akdolit ® Q90; purity ≥ 92%) doses were tested: 4 and 10% CaO on a TS basis, based on the common doses used when applying this pretreatment [21]. According to the literature, lime pretreatment requires long exposure times, ranging from several days to weeks, which can be reduced by increasing temperature [18]. For this reason, the following combinations of temperature and exposure time were tested: 4 days at room temperature (25°C) and 24 h at 55 and 72°C.…”

Section: Microalgae Pretreatmentmentioning

confidence: 99%

“…In fact, the combination of alkali and temperature could induce cellulose swelling, increasing the internal surface area and reducing the degree of crystallinity and polymerization [30]. Moreover, the hydrolysis of CH may occur through a variety of reactions induced by lime, including the disruption of H-bonds and saponification of intermolecular ester bonds in cellulose and hemicelluloses and crosslinking hemicellulose with other polymeric components [18]. Indeed, carbohydrate release after thermo-chemical pretreatment of microalgae has already been reported [10,28].…”

Section: Carbohydrate and Protein Solubilisationmentioning

confidence: 99%

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Enhancement of microalgae anaerobic digestion by thermo-alkaline pretreatment with lime (CaO)

et al. 2017

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The aim of this study was to evaluate for the first time the effect of a thermo-alkaline pretreatment with lime (CaO) on microalgae anaerobic digestion. The pretreatment was carried out by adding different CaO doses (4 and 10%) at different temperatures (room temperature (25 °C), 55 and 72 °C). The exposure time was 4 days for pretreatments at 25 °C, and 24 h for pretreatments at 55 and 72 °C. Following, a biochemical methane potential test was conducted with pretreated and untreated microalgae. According to the results, the pretreatment enhanced proteins solubilisation by 32.4% and carbohydrates solubilisation by 31.4% with the highest lime dose and temperature (10% CaO and 72 °C). Furthermore, anaerobic digestion kinetics were improved in all cases (from 0.08 to 0.14 day- 1 for untreated and pretreated microalgae, respectively). The maximum biochemical methane potential increase (25%) was achieved with 10% CaO at 72 °C, in accordance with the highest biomass solubilisation. Thus, lime pretreatment appears as a potential strategy to improve microalgae anaerobic digestion.Peer ReviewedPostprint (author's final draft

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“…Pretreatment methods have significant impact on the efficiency of ethanol production from biomass (Singh et al, ) because they change, in different ways depending of the pretreatment, some properties of the pretreated material, such as specific surface area, cellulose crystallinity index, polymerization degree, lignin, and acetyl content in the biomass (Kumar et al, ). Alkaline pretreatment processes remove acetyl and uronic acid groups present on hemicelluloses (Chang and Holtzapple, ; Garlock et al, ; Ramirez et al, ) and can be attractive, since hydrolyzates free of acetic acid can be obtained after enzymatic hydrolysis of the pretreated material, which avoids the need for a detoxification step.…”

Section: Introductionmentioning

confidence: 99%

Fermentation strategy for second generation ethanol production from sugarcane bagasse hydrolyzate by Spathaspora passalidarum and Scheffersomyces stipitis

Nakanishi

Soares

Biazi

et al. 2017

Biotech & Bioengineering

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Alcoholic fermentation of released sugars in pretreatment and enzymatic hydrolysis of biomass is a central feature for second generation ethanol (E2G) production. Saccharomyces cerevisiae used industrially in the production of first generation ethanol (E1G) convert sucrose, fructose, and glucose into ethanol. However, these yeasts have no ability to ferment pentose (xylose). Therefore, the present work has focused on E2G production by Scheffersomyces stipitis and Spathaspora passalidarum. The fermentation strategy with high pitch, cell recycle, fed-batch mode, and temperature decrease for each batch were performed in a hydrolyzate obtained from a pretreatment at 130°C with NaOH solution (1.5% w/v) added with 0.15% (w/w) of anthraquinone (AQ) and followed by enzymatic hydrolysis. The process strategy has increased volumetric productivity from 0.35 to 0.38 g · L · h (first to third batch) for S. stipitis and from 0.38 to 0.81 g · L · h for S. passalidarum (first to fourth batch). Mass balance for the process proposed in this work showed the production of 177.33 kg ethanol/ton of sugar cane bagasse for S. passalidarum compared to 124.13 kg ethanol/ton of sugar cane bagasse for S. stipitis fermentation. The strategy proposed in this work can be considered as a promising strategy in the production of second generation ethanol. Biotechnol. Bioeng. 2017;114: 2211-2221. © 2017 Wiley Periodicals, Inc.

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Fundamentals of Biomass Pretreatment at High pH

Cited by 15 publications

References 69 publications

Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass

Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass

Enhancement of microalgae anaerobic digestion by thermo-alkaline pretreatment with lime (CaO)

Fermentation strategy for second generation ethanol production from sugarcane bagasse hydrolyzate by Spathaspora passalidarum and Scheffersomyces stipitis

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