Kinetic and thermodynamic analysis of dilute acid hydrolysis of sugarcane bagasse

Tizazu, Belachew Zegale; Moholkar, Vijayanand S.

doi:10.1016/j.biortech.2017.11.032

Cited by 65 publications

(40 citation statements)

References 19 publications

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“…Most cellulases are inhibited in the presence of this lignocellulose-derived compounds ( Ximenes et al, 2010 , 2011 ; Maruthamuthu and Van Elsas, 2017 ), however, cellulases are found to be more sensitive to inhibition by some phenolic compounds than β-glucosidases ( Berlin et al, 2006 ; Ximenes et al, 2010 ). Furfural and 5-HMF concentrations in sugarcane bagasse hydrolysates pretreated by acid solution are 0.1–1.25% (w/v) and less than 0.1%, respectively ( Chen et al, 2012 ; Tizazu and Moholkar, 2018 ), whereas in corn stover the levels of 5-HMF and furfural were 0.001–0.004% and 0.0026–0.02% (w/v), respectively ( Du et al, 2010 ). Vanillin and 4-HBA appears in lower concentrations in corn stover hydrolysates, being vanillin ranging from 2.8 to 4.0 mg/L and 4-HBA around 0.028 mg/L.…”

Section: Discussionmentioning

confidence: 99%

Novel Ethanol- and 5-Hydroxymethyl Furfural-Stimulated β-Glucosidase Retrieved From a Brazilian Secondary Atlantic Forest Soil Metagenome

et al. 2018

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Beta-glucosidases are key enzymes involved in lignocellulosic biomass degradation for bioethanol production, which complete the final step during cellulose hydrolysis by converting cellobiose into glucose. Currently, industry requires enzymes with improved catalytic performance or tolerance to process-specific parameters. In this sense, metagenomics has become a powerful tool for accessing and exploring the biochemical biodiversity present in different natural environments. Here, we report the identification of a novel β-glucosidase from metagenomic DNA isolated from soil samples enriched with decaying plant matter from a Secondary Atlantic Forest region. For this, we employed a functional screening approach using an optimized and synthetic broad host-range vector for library production. The novel β-glucosidase – named Lfa2 – displays three GH3-family conserved domains and conserved catalytic amino acids D283 and E487. The purified enzyme was most active in pH 5.5 and at 50°C, and showed hydrolytic activity toward several pNP synthetic substrates containing β-glucose, β-galactose, β-xylose, β-fucose, and α-arabinopyranose, as well as toward cellobiose. Lfa2 showed considerable glucose tolerance, exhibiting an IC50 of 300 mM glucose and 30% of remaining activity in 600 mM glucose. In addition, Lfa2 retained full or slightly enhanced activity in the presence of several metal ions. Further, β-glucosidase activity was increased by 1.7-fold in the presence of 10% (v/v) ethanol, a concentration that can be reached in conventional fermentation processes. Similarly, Lfa2 showed 1.7-fold enhanced activity at high concentrations of 5-hydroxymethyl furfural, one of the most important cellulase inhibitors in pretreated sugarcane bagasse hydrolysates. Moreover, the synergistic effect of Lfa2 on Bacillus subtilis GH5-CBM3 endoglucanase activity was demonstrated by the increased production of glucose (1.6-fold). Together, these results indicate that β-glucosidase Lfa2 is a promissory enzyme candidate for utilization in diverse industrial applications, such as cellulosic biomass degradation or flavor enhancement in winemaking and grape processing.

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Section: Discussionmentioning

confidence: 99%

Novel Ethanol- and 5-Hydroxymethyl Furfural-Stimulated β-Glucosidase Retrieved From a Brazilian Secondary Atlantic Forest Soil Metagenome

et al. 2018

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“…[1,10] Hemicellulose has a random and amorphous structure, which can be easily hydrolyzed to pentoses (mainly xylose) at relative mild acidic reaction conditions, and further to furfural. [11] The cellulose is a polymer of glucose with crystalline structures, and hydrolysis of cellulose to LA requires a severer reaction condition. [1,10] Lignin, a phenolic polymer, is hard to be hydrolyzed in acidic hydrolysis conditions, though acid-soluble lignin can be dissolved.…”

Section: Introductionmentioning

confidence: 99%

“…Cellulose, hemicellulose and lignin, the three main organic constituents of lignocellulose, have different stability, generally hemicellulose < cellulose < acid‐insoluble lignin in hydrolysis conditions ,. Hemicellulose has a random and amorphous structure, which can be easily hydrolyzed to pentoses (mainly xylose) at relative mild acidic reaction conditions, and further to furfural . The cellulose is a polymer of glucose with crystalline structures, and hydrolysis of cellulose to LA requires a severer reaction condition ,.…”

Section: Introductionmentioning

confidence: 99%

Sequential Production of Xylose, Levulinic Acid and Activated Carbon from Pine Wood

et al. 2018

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In this work, a sequential production of bioenergy platform intermediates (i. e., xylose and levulinic acid (LA)) and carbon materials from pine wood was developed by a three‐step conversion technology. Firstly, the hemicellulose in pine wood was hydrolyzed, obtaining 12.8 wt% xylose and 68.9 wt% solid products containing cellulose and lignin. Secondly, the solid products were hydrolyzed, obtaining 30.6 wt% LA and 42.0 wt% solid residues containing humins and lignin. Thirdly, the solid residues were used for activated carbon (AC) production through potassium hydrate (KOH) activation followed by pyrolysis from 400–800 oC. An AC obtained at a pyrolysis temperature of 800 oC had a high Brunauer‐Emmett‐Teller (BET) surface area of 2436 m2/g and pore volume of 0.91 cm3/g, which exhibited an excellent reactive brilliant red X‐3B (RBRX‐3B) adsorption capacity of 892 mg/g. As a case, 1000 g of pine wood finally produced 128 g xylose, 211 g LA and 39 g high‐performance activated carbon.

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“…Finally, the kinetics of reducing and total sugar release was evaluated using artichoke wastes and cassava bagasse as examples of biomass. Kinetics analysis represents an interesting and complementary tool for identifying optimal conditions and permits the comparison of different technologies (Tizazu and Moholkar, 2018).…”

Section: Discussionmentioning

confidence: 99%

“…The direct treatment of artichoke by-product into acid solutions also demonstrated the higher efficiency of ultrasound application for releasing both reducing and total sugars. Tizazu et al (2018) reported that xylans from hemicellulose dissolves faster in acid medium and are quickly hydrolyzed, promoting a synergistic effect for sugar release. Changes in the acoustic fields and rheological behavior obtained showed the need to address these facts when developing ultrasound-assisted pretreatments with constant acoustic intensity application over the process.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the acid pretreatment of agroindustrial waste assisted by high-intensity ultrasound for further bioethanol production

Polachini¹

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ACKNOWLEDGMENTSThis study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior -Brasil (CAPES) -Finance Code 001. This study was also financed by CAPES to develop part of this PhD thesis in Spain under the grant number 88881.132626/2016-01. Thanks to the São Paulo Research Foundation (FAPESP) (Grant number 2017/06518-2) for their financial support to develop this project.At first, I would like to thank the Universitat Politècnica de València (UPV) and ASPA de amido) e no comportamento reológico (maior viscosidade) das suspensões prétratadas na presença de ultrassom. O campo acústico produzido nas suspensões sofreu uma redução durante a hidrólise, possivelmente devido às referidas alterações. Assim, pode-se concluir que o ultrassom de alta intensidade é uma tecnologia interessante para intensificar os pré-tratamentos de resíduos da agroindústria para a produção de bioetanol.Palavras-chave: Biomassa. Propriedades físicas. Campos acústicos. Hidrólise.Cinética. ABSTRACTThe pre-treatment of agroindustrial wastes is one of the most complex steps of their conversion process into bioethanol. This step consists basically of applying physical or chemical treatments in biomass in order to obtain carbohydrates partially hydrolyzed and more accessible for future action of enzymes and microorganisms. In this sense, the use of high-intensity ultrasound has been shown as a technology with an interesting potential, in combination with conventional methods, to enhance the mass and energy transfer processes. In the present study, it was characterized agroindustrial residues such as cassava bagasse, peanut shells and artichoke residues as potential materials for the production of bioethanol after acid pretreatment with and without the application of ultrasound. Thus, the different biomass/acid solutions systems were characterized according to their thermophysical properties (density, specific heat, thermal diffusivity and thermal conductivity) and rheological behavior. The acoustic fields generated in these different systems during ultrasound application were also characterized by a calorimetric method. Then, the ultrasonic intensity obtained in each case was related to the termophysical and reological properties. Subsequently, the kinetics of reducing and total sugar release and the structural changes produced in the suspensions considered during the pretreatments in acid solutions with conventional agitation or assisted by ultrasound were determined. The results obtained indicated that suspensions with higher acid concentration and higher solids content showed lower heat transfer capacity, given by the higher values for specific heat, thermal diffusivity, thermal conductivity. The same suspensions presented higher values of density and viscosity, which leads to greater resistance to flow. This fact was attributed, not only to the high viscosity, but also to the appearance of non-Newtonian rheological behavior as showed by the fitting of Herschel-Bulkley model. In these cases, the suspensions cont...

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Kinetic and thermodynamic analysis of dilute acid hydrolysis of sugarcane bagasse

Cited by 65 publications

References 19 publications

Novel Ethanol- and 5-Hydroxymethyl Furfural-Stimulated β-Glucosidase Retrieved From a Brazilian Secondary Atlantic Forest Soil Metagenome

Novel Ethanol- and 5-Hydroxymethyl Furfural-Stimulated β-Glucosidase Retrieved From a Brazilian Secondary Atlantic Forest Soil Metagenome

Sequential Production of Xylose, Levulinic Acid and Activated Carbon from Pine Wood

Evaluation of the acid pretreatment of agroindustrial waste assisted by high-intensity ultrasound for further bioethanol production

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