Changes in poplar (Populus trichocarpa) wood porous structure after liquid hot water (LHW) pretreatment

Changes in poplar (Populus trichocarpa) wood porous structure after liquid hot water (LHW) pretreatment. The aim of this research was to investigate the effect of applying different hydrothermal pretreatment conditions on the porous structure of poplar wood. Porosity is recognised as an important factor considering efficiency of an enzymatic hydrolysis as a step of bioethanol production. Native poplar wood as well as solid fractions after pretreatment performed at different temperatures (160 °C, 175 °C and 190 °C) were analysed. Porous structure was examined with an inverse size-exclusion chromatography (ISEC) method. Results indicated a significant development of the porous structure of the biomass with increasing porosity along with the growing temperature of the LHW process. The temperature of 190 °C was chosen as the most promising condition of poplar wood LHW pretreatment in terms of the efficiency of the subsequent steps of bioethanol production. The obtained results were consistent with the previous experimental data procured during analysis of the LHW pretreated poplar wood and its subsequent enzymatic hydrolysis yield.

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Assessment of the effectiveness of liquid hot water and steam explosion pretreatments of fast-growing poplar (Populus trichocarpa) wood

Wood Science and Technology ◽

10.1007/s00226-021-01350-1 ◽

2021 ◽

Author(s):

Andrzej Antczak ◽

Jan Szadkowski ◽

Dominika Szadkowska ◽

Janusz Zawadzki

Keyword(s):

Chemical Composition ◽

Enzymatic Hydrolysis ◽

Solid Fraction ◽

Steam Explosion ◽

Populus Trichocarpa ◽

Hot Water ◽

Fast Growing ◽

Liquid Hot Water ◽

Porosity Analysis ◽

Pretreated Biomass

AbstractIn this paper, the influence of physicochemical pretreatment methods on the chemical composition, enzymatic hydrolysis efficiency and porosity of fast-growing Populus trichocarpa wood was compared. Among the pretreatment methods, the liquid hot water (LHW) and steam explosion (SE) were used, which were performed at three different temperatures (160 °C, 175 °C and 190 °C) and two residence times (15 min and 1 h). The chemical composition, enzymatic hydrolysis and porosity analysis were done for native wood and solid fraction obtained after LHW and SE pretreatments. The porosity analysis was performed by inverse size exclusion chromatography method. Additionally, inhibitors of hydrolysis and fermentation processes in the liquid and solid fractions obtained after pretreatments were examined. Based on the results, it was found that the tested pretreatments caused the greatest changes in the chemical content of hemicelluloses. It was found that after LHW and SE pretreatments up to 99.1% or 94.0%, respectively, of hemicelluloses were removed from the obtained solid fraction. Moreover, the LHW and SE processes greatly enhanced the enzymatic digestibility of fast-growing poplar wood. The highest glucose yield was achieved after 15 min of SE pretreatment at 190 °C and was 676.4 mg/g pretreated biomass, while in the case of xylose the highest value (119.3 mg/g pretreated biomass) was obtained after 15 min of LHW pretreatment at 160 °C. Generally, after SE pretreatment process, more inhibitors were formed, and a greater effect of porous structure development was noticed than after LHW pretreatment. Despite this difference, the average glucose contents and yields after enzymatic hydrolysis of pretreated biomass were generally similar regardless of the pretreatment used.

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Enzymatic Hydrolysis and Fermentation of Banana Pseudostem Hydrolysate to Produce Bioethanol

International Journal of Microbiology ◽

10.1155/2021/5543104 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Lesetja Moraba Legodi ◽

Daniel Coenrad LaGrange ◽

Elbert Lukas Jansen van Rensburg ◽

Ignatious Ncube

Keyword(s):

Saccharomyces Cerevisiae ◽

Enzymatic Hydrolysis ◽

Agricultural Waste ◽

Hot Water ◽

Fermentable Sugars ◽

Protein G ◽

Bioethanol Production ◽

Liquid Hot Water ◽

Separate Hydrolysis And Fermentation ◽

Holocellulose Content

Banana pseudostem (BPS) is an agricultural waste with a high holocellulose content, which, upon hydrolysis, releases fermentable sugars that can be used for bioethanol production. Different pretreatment methods, namely, 3% (w/v) NaOH, 5% (v/v) H2SO4, and liquid hot water, applied on the BPS resulted in the availability of 52%, 48%, and 25% cellulose after treatment, respectively. Saccharification of the pretreated BPS with 10 FPU/g dry solids (29.3 mg protein/g d.s) crude enzyme from Trichoderma harzianum LMLBP07 13-5 at 50°C and a substrate loading of 10 to 15% released 3.8 to 21.8 g/L and from T. longibrachiatum LMLSAUL 14-1 released 5.4 to 43.5 g/L glucose to the biomass. Ethanol was produced through separate hydrolysis and fermentation (SHF) of alkaline pretreated BPS hydrolysate using Saccharomyces cerevisiae UL01 at 30°C and 100 rpm. Highest ethanol produced was 17.6 g/L. Banana pseudostem was shown as a potentially cheap substrate for bioethanol production.

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Box-Behnken design for the optimization of bioethanol production from rice straw and sugarcane bagasse by newly isolated Pichia occidentalis strain AS.2

Energy & Environment ◽

10.1177/0958305x211045010 ◽

2021 ◽

pp. 0958305X2110450

Author(s):

Ahmed K. Saleh ◽

Yasser R. Abdel-Fattah ◽

Nadia A. Soliman ◽

Maha M. Ibrahim ◽

Mohamed H. El-Sayed ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Rice Straw ◽

Sugarcane Bagasse ◽

Lignin Content ◽

Inoculum Size ◽

Hot Water ◽

Bioethanol Production ◽

Box Behnken Design ◽

Pretreatment Conditions ◽

Hydrolysis Of

This study investigated bioethanol production from rice straw (RS) and sugarcane bagasse (SCB) which containing 72.8 and 73.2% holocellulose, 56.8 and 58.6% α-cellulose, and 14.9 and 25.1% lignin for RS and SCB, respectively. To eliminate the lignin content, different pretreatment conditions, such as hot water, dilute acid, and acid-alkali, were designed. Acid-alkali was characterized as the best pretreatment for removing ∼79 and 70% of lignin, α-cellulose increased 91.4 and 91%, and holocellulose reached 90.8 and 90% for RS and SCB, respectively. The results revealed that acid-alkali was highly efficient than other pretreatment used for both RS and SCB. After enzymatic hydrolysis of acid-alkali-treated RS and SCB with cellulase, glucose concentrations reached 45 and 42 g/l, respectively. Pichia occidentalis AS.2 was isolated and identified based on 18S rRNA sequencing as a bioethanol producer. Maximization of bioethanol production by P. occidentalis AS.2 using the resulting glucose as a carbon source from RS and SCB was studied using an experimental design. The pH, incubation period, and inoculum size were optimized using Box-Behnken designs (BBD), the final conditions for bioethanol production used 100 g/l acid-alkali-treated fibers, 10 ml cellulase enzyme at 50°C for 5 days at 75 rpm for enzymatic hydrolysis. After time consumed and adjusting the pH to 6, the mixture was inoculated with 2.5% P. occidentalis AS.2 and incubated at 35°C for 24 h at 200 rpm to increase the bioethanol yield by 1.39-fold to 23.7 and 21.4 g/l compared to initial production (17 and 15.3 g/l) between RS and SCB, respectively.

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Diverse Banana Pseudostems and Rachis Are Distinctive for Edible Carbohydrates and Lignocellulose Saccharification towards High Bioethanol Production under Chemical and Liquid Hot Water Pretreatments

Molecules ◽

10.3390/molecules26133870 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3870

Author(s):

Jingyang Li ◽

Fei Liu ◽

Hua Yu ◽

Yuqi Li ◽

Shiguang Zhou ◽

...

Keyword(s):

Soluble Sugars ◽

Enzymatic Saccharification ◽

Hot Water ◽

Biofuel Production ◽

Bioenergy Crops ◽

Bioethanol Production ◽

Factors Affecting ◽

Liquid Hot Water ◽

Biomass Processing ◽

Banana Crops

Banana is a major fruit crop throughout the world with abundant lignocellulose in the pseudostem and rachis residues for biofuel production. In this study, we collected a total of 11 pseudostems and rachis samples that were originally derived from different genetic types and ecological locations of banana crops and then examined largely varied edible carbohydrates (soluble sugars, starch) and lignocellulose compositions. By performing chemical (H2SO4, NaOH) and liquid hot water (LHW) pretreatments, we also found a remarkable variation in biomass enzymatic saccharification and bioethanol production among all banana samples examined. Consequently, this study identified a desirable banana (Refen1, subgroup Pisang Awak) crop containing large amounts of edible carbohydrates and completely digestible lignocellulose, which could be combined to achieve the highest bioethanol yields of 31–38% (% dry matter), compared with previously reported ones in other bioenergy crops. Chemical analysis further indicated that the cellulose CrI and lignin G-monomer should be two major recalcitrant factors affecting biomass enzymatic saccharification in banana pseudostems and rachis. Therefore, this study not only examined rich edible carbohydrates for food in the banana pseudostems but also detected digestible lignocellulose for bioethanol production in rachis tissue, providing a strategy applicable for genetic breeding and biomass processing in banana crops.

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Liquid Hot Water Pretreatment and Enzymatic Hydrolysis as a Valorization Route of Italian Green Pepper Waste to Delivery Free Sugars

Foods ◽

10.3390/foods9111640 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1640

Author(s):

M.A. Martín-Lara ◽

L. Chica-Redecillas ◽

A. Pérez ◽

G. Blázquez ◽

G. Garcia-Garcia ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Liquid Fraction ◽

Hot Water ◽

Effect Of Temperature ◽

Green Pepper ◽

Free Sugars ◽

Liquid Hot Water Pretreatment ◽

Liquid Hot Water ◽

Water Pretreatment ◽

Hot Water Pretreatment

In this work, liquid hot water pretreatment (autohydrolysis) was used to improve enzymatic hydrolysis of a commonly consumed vegetable waste in Spain, Italian green pepper, to finally produce fermentable sugars. Firstly, the effect of temperature and contact time on sugar recovery during pretreatment (in insoluble solid and liquid fraction) was studied in detail. Then, enzymatic hydrolysis using commercial cellulase was performed with the insoluble solid resulting from pretreatment. The objective was to compare results with and without pretreatment. The results showed that the pretreatment step was effective to facilitate the sugars release in enzymatic hydrolysis, increasing the global sugar yield. This was especially notable when pretreatment was carried out at 180 °C for 40 min for glucose yields. In these conditions a global glucose yield of 61.02% was obtained. In addition, very low concentrations of phenolic compounds (ranging from 69.12 to 82.24 mg/L) were found in the liquid fraction from enzymatic hydrolysis, decreasing the possibility of fermentation inhibition produced by these components. Results showed that Italian green pepper is an interesting feedstock to obtain free sugars and prevent the enormous quantity of this food waste discarded annually.

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Optimizing Liquid Hot Water pretreatment conditions to enhance sugar recovery from wheat straw for fuel-ethanol production

Fuel ◽

10.1016/j.fuel.2008.06.009 ◽

2008 ◽

Vol 87 (17-18) ◽

pp. 3640-3647 ◽

Cited By ~ 163

Author(s):

J.A. Pérez ◽

I. Ballesteros ◽

M. Ballesteros ◽

F. Sáez ◽

M.J. Negro ◽

...

Keyword(s):

Ethanol Production ◽

Wheat Straw ◽

Fuel Ethanol ◽

Hot Water ◽

Sugar Recovery ◽

Liquid Hot Water Pretreatment ◽

Liquid Hot Water ◽

Water Pretreatment ◽

Pretreatment Conditions ◽

Hot Water Pretreatment

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Optimization of steam pretreatment conditions for enzymatic hydrolysis of poplar wood

Holzforschung ◽

10.1515/hf.2011.066 ◽

2011 ◽

Vol 65 (4) ◽

Cited By ~ 21

Author(s):

Fokko Schütt ◽

Jürgen Puls ◽

Bodo Saake

Keyword(s):

Enzymatic Hydrolysis ◽

Raw Material ◽

Steam Pretreatment ◽

Alkaline Extraction ◽

Poplar Wood ◽

Steam Refining ◽

Severity Factor ◽

Short Rotation ◽

Pretreatment Conditions ◽

Hydrolysis Of

Abstract Steam refining was investigated as a pretreatment for enzymatic hydrolysis of poplar wood from a short rotation plantation. The experiments were carried out without debarking to use an economically realistic raw material. Steam refining conditions were varied in the range of 3–30 min and 170–220°C, according to a factorial design created with the software JMP from SAS Institute Inc., Cary, NC, USA. Predicted steaming conditions for highest glucose and xylose yields after enzymatic hydrolysis were at 210°C and 15 min. Control tests under the optimized conditions verified the predicted results. Further pretreatments without bark showed that the enzymes were not significantly inhibited by the bark. The yield of glucose and xylose was 61.9% of theoretical for the experiments with the whole raw material, whereas the yield for the experiments without bark was 63.6%. Alkaline extraction of lignin from the fibers before enzymatic hydrolysis resulted in an increase of glucose yields from mild pretreated fibers and a decrease for severe pretreated fibers. The extracted lignin had a high content of xylose of up to 14% after very mild pretreatments. On the other hand, molecular weights of the extracted lignin increased substantially after pretreatments with a severity factor above 4. Hence, alkaline extraction of the lignin seems only attractive in a narrow range of steaming conditions.

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