Delignification efficiency of various types of biomass using microwave-assisted hydrotropic pretreatment

Mikulski, D.; Kłosowski, Grzegorz

doi:10.1038/s41598-022-08717-9

Cited by 24 publications

(11 citation statements)

References 41 publications

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“…However, to make the process economically viable, the selectivity must be increased, the pretreatment time reduced, and the chemicals recycled [ 41 , 45 ]. Furthermore, by separate usage or combining the alkaline treatment with physical techniques, such as microwave [ 46 , 47 , 48 , 49 ], ultrasound irradiation [ 18 , 19 , 41 , 49 , 50 , 51 ], or freeze–thaw (FT) cycles [ 44 , 47 , 52 ], the alkaline extraction can be improved even further taking into account the final objectives.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Alkaline Extraction of Xylan-Based Hemicelluloses from Wheat Straws: Effects of Microwave, Ultrasound, and Freeze–Thaw Cycles

et al. 2023

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The alkaline extraction of hemicelluloses from a mixture of three varieties of wheat straw (containing 40.1% cellulose, 20.23% xylan, and 26.2% hemicellulose) was analyzed considering the following complementary pre-treatments: freeze–thaw cycles, microwaves, and ultrasounds. The two cycles freeze–thaw approach was selected based on simplicity and energy savings for further analysis and optimization. Experiments planned with Design Expert were performed. The regression model determined through the response surface methodology based on the severity factor (defined as a function of time and temperature) and alkali concentration as variables was then used to optimize the process in a multi-objective case considering the possibility of further use for pulping. To show the properties and chemical structure of the separated hemicelluloses, several analytical methods were used: high-performance chromatography (HPLC), Fourier-transformed infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H-NMR), thermogravimetry and derivative thermogravimetry analysis (TG, DTG), and scanning electron microscopy (SEM). The verified experimental optimization result indicated the possibility of obtaining hemicelluloses material containing 3.40% glucan, 85.51% xylan, and 7.89% arabinan. The association of hot alkaline extraction with two freeze–thaw cycles allows the partial preservation of the hemicellulose polymeric structure.

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Section: Introductionmentioning

confidence: 99%

Optimization of Alkaline Extraction of Xylan-Based Hemicelluloses from Wheat Straws: Effects of Microwave, Ultrasound, and Freeze–Thaw Cycles

et al. 2023

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“…20%) and wheat straw (a reduction by ca. 45%) biomasses, but the results presented herein indicate that the application of a higher pressure significantly intensifies the process of the lignin removal [ 28 ]. Microwave-assisted pretreatment was conducted for 60 min, because in our earlier study delignification of different types of lignocellulosic biomass was conducted using microwaves and NaCS for 15, 30 and 60 min.…”

Section: Resultsmentioning

confidence: 99%

“…The extension of the duration of pretreatment from 15 to 60 min at 117 PSI resulted in an increase in the level of delignification, which increased the reduction of the content of lignins from 12.21 to 36.58% in pine chips biomass, from 22.49 to 57.68% in beech chips biomass and from 25.43 to 74.08% in wheat straw biomass. The coefficient of regression of the growth of the level of reduction of the lignin content over time in lignocellulosic biomass of different origin ranged from 0.8485 to 0.9679 [ 28 ]. Other authors have indicated that pretreatment using microwave radiation and 0.75% w/v NaOH leads to a reduction of lignin content by ca.10% in the biomass of catalpa sawdust [ 29 ].…”

Section: Resultsmentioning

confidence: 99%

High-pressure microwave-assisted pretreatment of softwood, hardwood and non-wood biomass using different solvents in the production of cellulosic ethanol

Mikulski

Kłosowski

2023

Biotechnol Biofuels

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Background Pretreatment is an indispensable stage of the preparation of lignocellulosic biomass with key significance for the effectiveness of hydrolysis and the efficiency of the production of cellulosic ethanol. A significant increase in the susceptibility of the raw material to further degradation can be attained as a result of effective delignification in high-pressure conditions. With this in mind, a method of high-pressure pretreatment using microwave radiation and various solvents (water, 40% w/v NaCS, 1% v/v H2SO4, 1% w/v NaOH or 60% v/v EtOH with an addition of 1% v/v H2SO4) was developed, enabling the acquisition of biomass with an increased susceptibility to the process of enzymatic hydrolysis. The medium obtained in this way can be used for the production of cellulosic ethanol via high-gravity technology (lignocellulosic media containing from 15 to 20% dry weight of biomass). For every type of biomass (pine chips, beech chips and wheat straw), a solvent was selected to be used during the pretreatment, guaranteeing the acquisition of a medium highly susceptible to the process of enzymatic hydrolysis. Results The highest efficiency of the hydrolysis of biomass, amounting to 71.14 ± 0.97% (glucose concentration 109.26 ± 3.49 g/L) was achieved for wheat straw subjected to microwave-assisted pretreatment using 40% w/v NaCS. Fermentation of this medium produced ethanol concentration at the level of 53.84 ± 1.25 g/L. A slightly lower effectiveness of enzymatic hydrolysis (62.21 ± 0.62%) was achieved after high-pressure microwave-assisted pretreatment of beech chips using 1% w/v NaOH. The hydrolysate contained glucose in the concentration of 91.78 ± 1.91 g/L, and the acquired concentration of ethanol after fermentation amounted to 49.07 ± 2.06 g/L. In the case of pine chips, the most effective delignification was achieved using 60% v/v EtOH with the addition of 1% v/v H2SO4, but after enzymatic hydrolysis, the concentration of glucose in hydrolysate was lower than in the other raw materials and amounted to 39.15 ± 1.62 g/L (the concentration of ethanol after fermentation was ca. 19.67 ± 0.98 g/L). The presence of xylose and galactose was also determined in the obtained fermentation media. The highest initial concentration of these carbohydrates (21.39 ± 1.44 g/L) was observed in beech chips media after microwave-assisted pretreatment using NaOH. The use of wheat straw after pretreatment using EtOH with an addition of 1% v/v H2SO4 for the preparation of fermentation medium, results in the generation of the initial concentration of galactose and xylose at the level of 19.03 ± 0.38 g/L. Conclusion The achieved results indicate a high effectiveness of the enzymatic hydrolysis of the biomass subjected to high-pressure microwave-assisted pretreatment. The final effect depends on the combined use of correctly selected solvents for the different sources of lignocellulosic biomass. On the basis of the achieved results, we can say that the presented method indicates a very high potential in the area of its use for the production of cellulosic ethanol involving high-gravity technology.

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“…The details of the Klason lignin method and the UV-vis spectroscopic method are described in the ESI Method S4. † On the basis of the LP value determined by either the Klason lignin or the UV-vis spectroscopic method, the change in the LP of each sample was calculated according to eqn (3), 39 where LP 0 is the initial LP of MBW, and LP is the LP of each sample.…”

Section: Methodsmentioning

confidence: 99%

Enhanced depolymerization of beech wood lignin and its removal with peroxidases through continuous separation of lignin fragments

Teo,

Kondo,

Saito

et al. 2023

Green Chem.

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Delignification efficiency of various types of biomass using microwave-assisted hydrotropic pretreatment

Cited by 24 publications

References 41 publications

Optimization of Alkaline Extraction of Xylan-Based Hemicelluloses from Wheat Straws: Effects of Microwave, Ultrasound, and Freeze–Thaw Cycles

Optimization of Alkaline Extraction of Xylan-Based Hemicelluloses from Wheat Straws: Effects of Microwave, Ultrasound, and Freeze–Thaw Cycles

High-pressure microwave-assisted pretreatment of softwood, hardwood and non-wood biomass using different solvents in the production of cellulosic ethanol

Enhanced depolymerization of beech wood lignin and its removal with peroxidases through continuous separation of lignin fragments

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