Articoli di riviste: "Pretreatment"

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Adiandri, R. S., R. Purwadi, Hoerudin e T. Setiadi. "Recent Methods in the Pretreatment of Corncob Wastes for Value-Added Bioproducts Carbon Sources". IOP Conference Series: Earth and Environmental Science 1024, n. 1 (1 maggio 2022): 012032. http://dx.doi.org/10.1088/1755-1315/1024/1/012032.

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Abstract Corncobs are composed of cellulose, hemicellulose, and lignin. Cellulose and hemicellulose are monomeric sugars that can be utilized as carbon sources for microbial growth and bioproduct formation. However, corncobs present several challenges due to their complex and recalcitrant nature. Addressing these challenges for increased enzymatic and microbial accessibility requires pretreatment methods to break down resistant structures, thus enabling the recovery of fermentable sugars. Different pretreatment methods on corncob wastes have been studied extensively: chemical, physicochemical, and combined pretreatments. Among the developed pretreatment methods, combined pretreatments are the most widely used in the corncob pretreatment process to overcome various limitations in a single pretreatment method. Several combined pretreatment can increase sugar production, shorten processing time and repress inhibitor formation. This review article would assist in determining the best pretreatment method for corncobs according to the advantages, challenges, and effectiveness of various pretreatment methods

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Ethaib, Saleem, Rozita Omar, Mustapa Kamal Siti Mazlina e Awang Biak Dayang Radiah. "Evaluation of the Interactive Effect Pretreatment Parameters via Three Types of Microwave-Assisted Pretreatment and Enzymatic Hydrolysis on Sugar Yield". Processes 8, n. 7 (6 luglio 2020): 787. http://dx.doi.org/10.3390/pr8070787.

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This study aims to evaluate the sugar yield from enzymatic hydrolysis and the interactive effect pretreatment parameters of microwave-assisted pretreatment on glucose and xylose. Three types of microwave-assisted pretreatments of sago palm bark (SPB) were conducted for enzymatic hydrolysis, namely: microwave-sulphuric acid pretreatment (MSA), microwave-sodium hydroxide pretreatment (MSH), and microwave-sodium bicarbonate (MSB). The experimental design was done using a response surface methodology (RSM) and Box–Behenken Design (BBD). The pretreatment parameters ranged from 5–15% solid loading (SL), 5–15 min of exposure time (ET), and 80–800 W of microwave power (MP). The results indicated that the maximum total reducing sugar was 386 mg/g, obtained by MSA pretreatment. The results also illustrated that the higher glucose yield, 44.3 mg/g, was found using MSH pretreatment, while the higher xylose yield, 43.1 mg/g, resulted from MSA pretreatment. The pretreatment parameters MP, ET, and SL showed different patterns of influence on glucose and xylose yield via enzymatic hydrolysis for MSA, MSH, and MSB pretreatments. The analyses of the interactive effect of the pretreatment parameters MP, ET, and SL on the glucose yield from SPB showed that it increased with the high MP and longer ET, but this was limited by low SL values. However, the analysis of the interactive effect of the pretreatment parameters on xylose yields revealed that MP had the most influence on the xylose yield for MSA, MSH, and MSB pretreatments.

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Liu, Yutao, Xicun Chai e Mingmei Chi. "Effects of a Pretreatment Combining Rubbing with Dilute Alkali on the Enzymatic Hydrolysis-Reducing Sugar Yield and Structure of Rice Straw". Transactions of the ASABE 62, n. 6 (2019): 1705–11. http://dx.doi.org/10.13031/trans.13627.

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Abstract. Current pretreatments to digest cellulose straw are characterized by high energy consumption, environmental pollution, and other problems that limit straw biomass utilization. In this work, a rice straw rubbing pretreatment that is less energy-intensive than existing pretreatments is proposed to partly destroy the silicon layer. The rubbing pretreatment did not significantly increase the enzymatic hydrolysis-reducing sugar production rate of rice straw, but it enhanced the effect of subsequent dilute alkali pretreatment. The enzymatic hydrolysis-reducing sugar production rate after combined rubbing and alkali pretreatment was 33.63%, which was significantly higher than the rates achieved with original straw and with dilute alkali pretreatment alone. Rubbing pretreatment removed 33.40% of the surface silicon from the straw. This was significantly higher than the removal rates for original straw and dilute alkali pretreatment alone, but there was no marked difference in removal rate between the rubbing pretreatment and the combined rubbing and alkali pretreatment. The results indicate that rubbing pretreatment is an effective way to promote the efficiency of alkali pretreatment, and combined rubbing and alkali pretreatment greatly enhances the efficient utilization of rice straw.Highlights33.40% of the silicon layer on the surface of rice straw was removed by the rubbing pretreatment.Cracks caused by the rubbing pretreatment are beneficial for chemical reagents to access the inner composites.The rubbing pretreatment could enhance the efficiency of follow-up treatments for rice straw. Keywords: Rice straw, Rubbing pretreatment, Silicon layer, Sugar yield, Structure.

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Hendrasetiafitri, Citasari, Yong Joo Sung e Dong-Seop Kim. "Effects of pretreatments on the chemical composition and thermal conversion of oil palm empty fruit bunch". BioResources 17, n. 2 (28 marzo 2022): 2727–42. http://dx.doi.org/10.15376/biores.17.2.2727-2742.

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The combustion of oil palm empty fruit bunch (OPEFB) can cause severe fouling, slagging, and ash melt-down problems, which originate from its non-organic components such as potassium, calcium, and silicon. To improve the usability of OPEFB as raw materials for combustion energy generation, the effects of pretreatments with various solution on the chemical composition and the thermal degradation were investigated. Soaking pretreatments with alkali, acidic, and neutral conditions were applied. The acid soaking pretreatments resulted in the reduction of the alkaline ash materials, although the silicon and the chlorine were effectively reduced by the alkali or the water soaking pretreatment. The changes in the ash composition by the different pretreatment conditions resulted in the changes of thermal properties. The pretreated OPEFB showed increased thermal degradation temperatures, indicating the improvement of the thermal stability by the pretreatment. The results of the various pretreatments showed that the water soaking pretreatment of OPEFB could be a promising pretreatment method to improve the applicability for combustion as a bio-fuel, in terms of economic viability and environmental sustainability.

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Yao, Lan, Chang Geun Yoo, Yunqiao Pu, Xianzhi Meng, Wellington Muchero, Gerald A. Tuskan, Timothy J. Tschaplinski, Arthur J. Ragauskas e Haitao Yang. "Physicochemical changes of cellulose and their influences on Populus trichocarpa digestibility after different pretreatments". BioResources 14, n. 4 (21 ottobre 2019): 9658–76. http://dx.doi.org/10.15376/biores.14.4.9658-9676.

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Pretreatment is commonly used to reduce recalcitrance of the lignin-carbohydrate matrix. In this study, leading pretreatment technologies, including dilute sulfuric acid, liquid hot water, alkaline, and organosolv pretreatments, were applied to the selected Populus trichocarpa genotype with relatively low lignin content to elucidate cellulose physicochemical property changes and digestibility-related factors. Pretreated Populus trichocarpa (BESC 131) exhibited higher accessibility and glucose yield than the untreated biomass. Chemical composition and Fourier transform infrared (FTIR) analysis results revealed that hemicellulose and lignin were removed to a varying extent depending on the pretreatment techniques applied. The degree of polymerization of the cellulose was decreased to the largest extent after dilute acid pretreatment, followed by organosolv, alkaline, and liquid hot water pretreatments. Cellulose crystallinity index was slightly changed after the pretreatments; however, its differences were not remarkable between those pretreatment techniques. Among four different pretreatments, organosolv was the most effective pretreatment technology in terms of sugar release, which was three times higher than that of the untreated native biomass. Among all of the tested cell wall traits, the lignin content of Populus trichocarpa was the most remarkable feature associated with glucose release, though Populus trichocarpa recalcitrance was not solely dependent on any single factor.

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Liu, Chao, Rui Zhang, Jingjie Yu, Jing Chang e Wenjuan Zhang. "Comparative study of single stage and two-stage pretreatments on corn stover: A kinetic assessment". BioResources 17, n. 1 (5 gennaio 2022): 1257–69. http://dx.doi.org/10.15376/biores.17.1.1257-1269.

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The effects of two-stage pretreatment consisting of tepid water (first stage) and FeCl3 (second stage) pretreatments on hemicellulose hydrolysis were investigated. A kinetic comparison between the single stage (FeCl3-only pretreatment) and the two-stage pretreatment was evaluated. Compared with single stage pretreatment, the two-stage pretreatment decreased the activation energy Ea of hemicellulose hydrolysis by 38.3% and decreased the optimal reaction time by 34.8%. Besides, the xylose content increased by 14.9% and the catalyst dosage decreased by 31.9% in the two-stage pretreatment. This study provided an efficient pretreatment process for hemicellulose hydrolysis.

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Schroeder, Bruna Grosch, Havva Betül İstanbullu, Matthias Schmidt, Washington Logroño, Hauke Harms e Marcell Nikolausz. "Effect of Alkaline and Mechanical Pretreatment of Wheat Straw on Enrichment Cultures from Pachnoda marginata Larva Gut". Fermentation 9, n. 1 (11 gennaio 2023): 60. http://dx.doi.org/10.3390/fermentation9010060.

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In order to partially mimic the efficient lignocellulose pretreatment process performed naturally in the gut system of Pachnoda marginata larvae, two wheat straw pretreatments were evaluated: a mechanical pretreatment via cutting the straw into two different sizes and an alkaline pretreatment with calcium hydroxide. After pretreatment, gut enrichment cultures on wheat straw at alkaline pH were inoculated and kept at mesophilic conditions over 45 days. The methanogenic community was composed mainly of the Methanomicrobiaceae and Methanosarcinaceae families. The combined pretreatment, size reduction and alkaline pretreatment, was the best condition for methane production. The positive effect of the straw pretreatment was higher in the midgut cultures, increasing the methane production by 192%, while for hindgut cultures the methane production increased only by 149% when compared to non-pretreated straw. Scanning electron microscopy (SEM) showed that the alkaline pretreatment modified the surface of the wheat straw fibers, which promoted biofilm formation and microbial growth. The enrichment cultures derived from larva gut microbiome were able to degrade larger 1 mm alkaline treated and smaller 250 µm but non-pretreated straw at the same efficiency. The combination of mechanical and alkaline pretreatments resulted in increased, yet not superimposed, methane yield.

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Mahmood, Hamayoun, Saqib Mehmood, Ahmad Shakeel, Tanveer Iqbal, Mohsin Ali Kazmi, Abdul Rehman Khurram e Muhammad Moniruzzaman. "Glycerol Assisted Pretreatment of Lignocellulose Wheat Straw Materials as a Promising Approach for Fabrication of Sustainable Fibrous Filler for Biocomposites". Polymers 13, n. 3 (26 gennaio 2021): 388. http://dx.doi.org/10.3390/polym13030388.

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Glycerol pretreatment is a promising method for the environmentally-friendly transformation of lignocellulosic materials into sustainable cellulose-rich raw materials (i.e., biopolymer) to fabricate biocomposites. Here, a comparison of aqueous acidified glycerol (AAG) pretreatment of wheat straw (WS) with alkaline, hot water, and dilute acid pretreatments on the thermal and mechanical characteristics of their fabricated composite board is presented. A comparison of total energy expenditure during WS pretreatment with AAG and other solutions was estimated and a comparative influence of AAG processing on lignocellulosic constituents and thermal stability of WS fiber was studied. Results imply that AAG pretreatment was superior in generating cellulose-rich fiber (CRF) as compared to other pretreatments and enhanced the cellulose contents by 90% compared to raw WS fiber. Flexural strength of acidic (40.50 MPa) and hot water treated WS composite (38.71 MPa) was higher compared to the value of 33.57 MPa for untreated composite, but AAG-treated composites exhibited lower values of flexural strength (22.22 MPa) compared to untreated composite samples. Conversely, AAG pretreatment consumed about 56% lesser energy for each kg of WS processed as compared to other pretreatments. These findings recognize that glycerol pretreatment could be a clean and new pretreatment strategy to convert agricultural waste into high-quality CRF as a sustainable raw material source for engineered biocomposite panels.

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Alba-Galvín, Juan, Leandro González-Rovira, Manuel Bethencourt, Francisco Botana e José Sánchez-Amaya. "Influence of Aerospace Standard Surface Pretreatment on the Intermetallic Phases and CeCC of 2024-T3 Al-Cu Alloy". Metals 9, n. 3 (12 marzo 2019): 320. http://dx.doi.org/10.3390/met9030320.

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A standard three-step surface pretreatment employed in the aerospace sector for Al alloys have been investigated prior to the generation of cerium conversion coatings (CeCC) on aluminium-copper alloy 2024. Two pretreatments were analysed, one without final acid etching (Pretreatment 1) and another with this step (Pretreatment 2). Both pretreatments affect the alloy intermetallic phases, playing a key role in the development of the CeCC, and also in the susceptibility to localised corrosion in NaCl medium. Scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX) revealed that after Pretreatment 2, Al(Cu,Mg) phases were partially or totally removed through dealloying with their subsequent copper enrichment. Conversely, none of these intermetallic phases were affected when the final acid step was not employed (Pretreatment 1). Meanwhile, Al-Cu-Fe-Mn-(Si) phases, the other major Al–Cu alloys intermetallics, suffers minor changes through the whole pretreatments chain. The protective efficiency of CeCC was evaluated using electrochemical techniques based on linear polarisation (LP) and electrochemical impedance spectroscopy (EIS). Samples with CeCC deposited after the Pretreatment 1 gave higher polarisation resistance and impedance module than CeCC deposited after Pretreatment 2. SEM-EDX and X-ray photoelectron spectroscopy analysis (XPS) indicate that the main factors explaining the corrosion resistance of the coatings is the existence of Al(Cu,Mg) intermetallics in the surface of the alloy, which promote the deposition of a cerium-based coating rich in Ce4+ compounds. These Al(Cu,Mg) intermetallics were kept in the 2024 alloy when acid etching was not employed (Pretreatment 1).

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Rezania, Shahabaldin, Hossein Alizadeh, Jinwoo Cho, Negisa Darajeh, Junboum Park, Beshare Hashemi, Mohd Fadhil Md Din et al. "Changes in composition and structure of water hyacinth based on various pretreatment methods". BioResources 14, n. 3 (12 giugno 2019): 6088–99. http://dx.doi.org/10.15376/biores.14.3.6088-6099.

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The deconstruction of cellulose, hemicellulose, and lignin has varying effects on lignocellulosic biomass. To understand and evaluate these effects it is important to conduct compositional and structural analyses. In this study, the effect of different pretreatments on the composition and structure of water hyacinth (WH) was investigated. The pretreatment methods investigated were acid, alkali, ionic liquid (IL), and microwave-alkali. The structural analysis was completed before and after the pretreatment using scanning electron microscopy. In addition, the biomass recovery rate was measured to evaluate the composition of the WH biomass. Based on the results, all pretreatment methods effectively disrupted the crystalline structure and enhanced the digestibility of the WH through increasing the cellulose and hemicellulose content and reducing the lignin content. The acid pretreatment resulted in high cellulose digestibility while the microwave-alkali pretreatment destroyed only the lignin structure of the WH. The alkali and IL pretreatments increased the cellulose and hemicellulose content of the WH. The highest recovery rate was obtained via IL pretreatment. The acid, microwave-alkali, and alkali pretreatments had the second, third, and fourth highest recovery rates, respectively. This study showed that the biomass recovery rate, compositional makeup, and structural analysis are important to use WH for bioenergy production.

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Antczak, Andrzej, Jan Szadkowski, Dominika Szadkowska e Janusz Zawadzki. "Assessment of the effectiveness of liquid hot water and steam explosion pretreatments of fast-growing poplar (Populus trichocarpa) wood". Wood Science and Technology 56, n. 1 (6 dicembre 2021): 87–109. http://dx.doi.org/10.1007/s00226-021-01350-1.

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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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Penmatsa, Varun, Hiroshi Kawarada, Yin Song e Chunlei Wang. "Comparison of Different Oxidation Techniques for Biofunctionalization of Pyrolyzed Carbon". Material Science Research India 11, n. 1 (30 agosto 2014): 01–08. http://dx.doi.org/10.13005/msri/110101.

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Pyrolyzed carbon micro/nano-structures have great potential as functional units in biosensors where biofunctionalization of the carbon surface is a requisite. In this work, we present a comparison of four different oxidation pretreatments, i.e. vacuum ultraviolet (VUV), electrochemical activation (EA), oxygen reactive ion etching (RIE), and ultraviolet/ozone (UV/O3) pretreatments on pyrolyzed carbon surface. X-ray photoelectron spectroscopy (XPS) results indicated that all the oxidation techniques except UV/O3 pretreatment yielded identical oxidation levels. The percentage of the carboxyl group which is suitable for covalent attachment of amine terminated biomolecules increased with pretreatment time, and was highest in the case of VUV pretreatment (15%) followed by oxygen RIE (12.5%) and EA pretreatments (12.5%) and UV/O3 pretreatment showed significantly lower carboxyl group percentage at 6%. This study helps to optimize the surface functionalization conditions for covalent binding of bioreceptors on the pyrolyzed carbon substrate for biosensing applications.

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Augustina, Sarah, Imam Wahyudi, Wahyu Dwianto e Teguh Darmawan. "Effect of Sodium Hydroxide, Succinic Acid and Their Combination on Densified Wood Properties". Forests 13, n. 2 (11 febbraio 2022): 293. http://dx.doi.org/10.3390/f13020293.

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The effect of NaOH, succinic acid and their combination used as pretreatments on selected properties of densified wood samples of pisang putih (Mezzettia spp.), nyatoh (Palaquium spp.) and sepetir (Sindora spp.) has been studied. The properties of these samples were then compared with those of untreated wood (control) and densified wood samples without any pretreatment (HD wood). For alkali-pretreatment, after immersion in 10% NaOH (w/w) for 1, 2 and 3 h, the samples were immediately compressed; for acid-pretreatment, the sample was impregnated with 10% succinic acid (w/w) using a vacuum of −50 kPa for 30 min and a pressure of 7 bar for 2 h before pressing; while for the combination-pretreatment, the sample was initially immersed in 10% NaOH then impregnated with 10% succinic acid (w/w) and finally densified/compressed. Compression was applied in a radial direction and carried out in an open system using a hot press machine at 180 °C and 7 MPa specific pressure for 30 min with a 40% compression ratio. The results showed that densified wood with or without pretreatment had a higher specific gravity (SG) than the control, whereas sepetir wood showed the greatest increase in SG. The alkali- and combination-pretreatments resulted in a higher C-set value than in the control, HD and acid-pretreated samples. Acid-pretreatment resulted in the best improvement in dimensional stability compared to the other pretreatments. Increasing the immersion time in NaOH solution was proven to be able to increase dimensional stability both in alkali- and combination-pretreatments, although water absorption values varied.

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Yang, Xiaorui, Xiaotong Li, Jinhua Liang e Jianliang Zhu. "Comparative Study of Effective Pretreatments on the Structural Disruption and Hydrodepolymerization of Rice Straw". Sustainability 15, n. 6 (7 marzo 2023): 4728. http://dx.doi.org/10.3390/su15064728.

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Rice straw (RS) is the most potentially renewable agricultural waste resource widely distributed in nature. Considering the complex recalcitrant structure and components of RS, three pretreatment methods, including high-temperature hydrothermal, medium-temperature microwave, and low-temperature cryocrushing pretreatment were performed. The components and structure of RS residues were examined and analyzed after the pretreatments. Pretreatment with hydrothermal yielded the lowest rice straw recovery (59.0%); after being pretreated at 180 °C for 10 min, the hemicellulose recovery was only 14.1%, and the removal efficiency of lignin was the largest (32.2%), which was 18.8% higher than that achieved from cryocrushing and microwave pretreatment, respectively. Pretreatment with cryocrushing yielded the highest recovery rates of rice straw (92.9%), hemicellulose and cellulose (88.8% and 90.4%, respectively). Results of scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and the analysis of specific surface area and apertures demonstrated that all three pretreatments could effectively disrupt the structure of RS and reduce its cellulose crystallinity. The three pretreatments were found to enhance the hydrodepolymerization of RS residues. Furthermore, cryocrushing pretreatment yielded the highest cellulose conversion rate (56.8%), and the yields of glucose, xylose, and arabinose were 29.6%, 56.2%, and 17.8%, respectively. Apart from the use of acids and enzymes, hydrodepolymerization of RS was among the few methods that can effectively degrade cellulose, presenting an ideal solution for the degradation of biomass.

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Odisi, Estácio Jussie, André Oliveira de Souza Lima, Vivian Colonetti, Rômulo Couto Alves, Andressa Gilioli e Mara Gabriela Novy Quadri. "Enzymatic Saccharification of Sugarcane Bagasse Using Ash - Supplemented Hydrogen Peroxide as Pre-Treatment". International Journal of Advanced Engineering Research and Science 9, n. 11 (2022): 200–214. http://dx.doi.org/10.22161/ijaers.911.26.

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Purpose: Enzymatic saccharification of sugarcane bagasse with cellulases was investigated after hydrogen peroxide pretreatment. Methods: Two pretreatments, alkaline hydrogen peroxide and hydrogen peroxide supplemented with ash were compared in their performance in the improvement of the susceptibility of bagasse to enzymatic action. The reaction yield was evaluated by the reducing sugar content released from the pretreated bagasse after 48 hours of enzymatic hydrolysis, and the best condition was found for both treatments. Results: The yield, expressed in reducing sugars for the alkaline hydrogen peroxide pretreatment was 217.6 mg g-1 bagasse, and 179.9 mg g-1 bagasse for hydrogen peroxide ash pretreatment; the untreated bagasse provided 74.3 mg g-1 bagasse yield, showing the effectiveness of the two pretreatments. Conclusion: The pretreatment with hydrogen peroxide supplemented with ashes appears more feasible for implementation since alkali addition in the pretreatment delivers many caustic residues that need expensive washing process and generate aggressive effluents into the environment; besides alkali addition promotes partial degradation of hemicellulose.

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Wei, Hui, Wei Wang, Peter N. Ciesielski, Bryon S. Donohoe, Min Zhang, Michael E. Himmel, Xiaowen Chen e Melvin P. Tucker. "Ferrous and Ferric Ion-Facilitated Dilute Acid Pretreatment of Lignocellulosic Biomass under Anaerobic or Aerobic Conditions: Observations of Fe Valence Interchange and the Role of Fenton Reaction". Molecules 25, n. 6 (20 marzo 2020): 1427. http://dx.doi.org/10.3390/molecules25061427.

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Ferrous ion co-catalyst enhancement of dilute-acid (DA) pretreatment of biomass is a promising technology for increasing the release of sugars from recalcitrant lignocellulosic biomass. However, due to the reductive status of ferrous ion and its susceptibility to oxidation with exposure to atmosphere, its effective application presumably requires anaerobic aqueous conditions created by nitrogen gas-purging, which adds extra costs. The objective of this study was to assess the effectiveness of oxidative iron ion, (i.e., ferric ion) as a co-catalyst in DA pretreatment of biomass, using an anaerobic chamber to strictly control exposure to oxygen during setup and post-pretreatment analyses. Remarkably, the ferric ions were found to be as efficient as ferrous ions in enhancing sugar release during DA pretreatment of biomass, which may be attributed to the observation that a major portion of the initial ferric ions were converted to ferrous during pretreatment. Furthermore, the detection of hydrogen peroxide in the liquors after DA/Fe ion pretreatment suggests that Fenton reaction chemistry was likely involved in DA/Fe ion pretreatments of biomass, contributing to the observed ferric and ferrous interchanges during pretreatment. These results help define the extent and specification requirements for applying iron ions as co-catalysts in DA pretreatments of biomass.

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Johannes, Lovisa Panduleni, e Tran Dang Xuan. "Comparative Analysis of Acidic and Alkaline Pretreatment Techniques for Bioethanol Production from Perennial Grasses". Energies 17, n. 5 (22 febbraio 2024): 1048. http://dx.doi.org/10.3390/en17051048.

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This review paper examines acid and alkaline pretreatments on perennial grasses for second-generation (2G) bioethanol production, a relatively unexplored area in this field. It compares the efficiency of these pretreatments in producing fermentable sugar and bioethanol yield. This study finds that alkaline pretreatment is more effective than acidic pretreatment in removing lignin and increasing sugar yield, leading to higher ethanol yields. However, it is costlier and requires longer reaction times than acidic pretreatment, while acidic pretreatment often leads to the formation of inhibitory compounds at higher temperatures, which is undesirable. The economic and environmental impacts of lignocellulosic biomass (LCB) are also assessed. It is revealed that LCB has a lower carbon but higher water footprint and significant costs due to pretreatment compared to first-generation biofuels. This review further explores artificial intelligence (AI) and advanced technologies in optimizing bioethanol production and identified the gap in literature regarding their application to pretreatment of perennial grasses. This review concludes that although perennial grasses hold promise for 2G bioethanol, the high costs and environmental challenges associated with LCB necessitate further research. This research should focus on integrating AI to optimize the pretreatment of LCB, thereby improving efficiency and sustainability in 2G biofuel production.

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Alvarez-Barreto, Jose F., Fernando Larrea, Maria C. Pinos C, Jose Benalcázar, Daniela Oña, Daniela A. Viteri, Marco Leon e Daniela Almeida-Streitwieser D. "Chemical Pretreatments on Residual Cocoa Pod Shell Biomass for Bioethanol Production". Bionatura 6, n. 1 (15 febbraio 2021): 1490–500. http://dx.doi.org/10.21931/rb/2020.06.01.9.

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Cocoa pod shell is an essential agricultural residue in Ecuador, and this study addressed its potential valorization for bioethanol production. For this, three types of pretreatments, acid, alkaline, and autohydrolysis, were applied to pod shells from two different cocoa types, national and CCN-51. to remove the lignin. Untreated and treated biomasses were characterized by composition, thermal stability, Fourier transformed infrared spectroscopy (FITR), and scanning electron microscopy (SEM). The treated biomass was then enzymatically hydrolyzed with cellulase. Reducing sugars were quantified after pretreatments and enzymatic hydrolysis, and the pretreatment liquors and the enzymatic hydrolysates were subjected to alcoholic fermentation with Saccharomyces cerevisiae. There were substantial differences in composition between both biomasses, particularly in lignin content, with national cocoa having the lowest values. All pretreatment conditions had significant effects on biomass composition, structure, and thermal properties. After alkaline pretreatment, the biomass presented the highest cellulose and lowest lignin contents, resulting in the highest reducing sugar concentration in the pretreatment liquor. The highest lignin content was found after the acid pretreatment, which resulted in low, reducing sugar concentrations. Autohydrolysis produced similar results as the acid pretreatment; however, it resulted in the highest sugar concentration after enzymatic hydrolysis, while the acid-treated sample had negligible levels. After fermentation, there were no differences in productivity among the pretreatment liquors, but autohydrolysis had the largest ethanol yield. In the hydrolysates, it was also autohydrolysis that resulted in higher productivity and yield. Thus, there is an indication of the formation of inhibitors, both enzymatic activity and ethanol production, in the acid and alkaline pretreatments, and this should be tackled in future research. Nonetheless, given the crucial changes observed in biomass, we believe that cocoa pod shell pretreatment has potential for the generation of reducing sugars that could be further used in different bioprocesses, nor only bioethanol production.

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Jia, Zhixin, Ying Zheng e Jinghong Zhou. "Effects of different pretreatment methods on the enzymatic hydrolysis of cassava residue". BioResources 14, n. 3 (12 giugno 2019): 6060–78. http://dx.doi.org/10.15376/biores.14.3.6060-6078.

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The enzymatic hydrolysis of cassava residue treated by a hot water (HW) pretreatment, an extreme-low acid (ELA) pretreatment, and an alkaline hydrogen peroxide (AHP) pretreatment was investigated. The results showed that the ELA pretreatment dissolved greater xylan and glucose quantities than the HW pretreatment under the same conditions, and the xylan and glucan contents of the pretreated substrate affected the subsequent cellulase hydrolysis. The conversion to glucose by cellulase hydrolysis reached 81.4% after the HW pretreatment, while the glucose yields under the ELA and AHP pretreatment conditions were 78.3% and 71.0%, respectively. In addition, supplementation with xylanase improved cellulase efficiency. At an equal xylanase dosage, a higher glucose yield (i.e., 91.3%) was achieved for the ELA-pretreated substrates that contained a lower xylan content. Xylanase supplementation in the AHP pretreatment had little effect on the glucose conversion. Finally, X-ray diffraction studies showed that the HW and ELA pretreatments increased the cassava residue crystallinity, while the AHP pretreatment had little effect.

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Kazeem, M. O., K. A. Ajijolakewu, A. M. Ahmed El - Imam e R. B. Salau. "Tamarind extract pretreatment: Valorization of sugarcane bagasse for cellulase production by Aspergillus flavus". Ife Journal of Science 23, n. 2 (16 novembre 2021): 25–34. http://dx.doi.org/10.4314/ijs.v23i2.3.

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Effective pretreatment is crucial for cellulase production from sugarcane bagasse. Pretreatment with tamarind extract could reduce the hazardous effect associated with chemical pretreatment. The present work investigated tamarind (Tamarindus indica) extract in combination with H2SO4 and thermal pretreatment of sugarcane bagasse for cellulase production by Aspergillus flavus. The sugarcane bagasse was pretreated with tamarind extract pH 2 and pH 4, followed by 1% H2SO4 and thermal treatment at 121°C for 15 min. The pretreatment slurry was analysed for reducing sugar while solid bagasse was analysed for weight loss. Aspergillus flavus grew on sugarcane bagasse under solid state fermentation and the Carboxy Methyl Cellulase (CMCase) and Filter Paper Assay (FPA) activities were compared on the various pretreatments. The pretreatments changed the visible morphology of the sugarcane bagasse observed by the swelling, fibrous appearance and colour change. Pretreatment slurry yielded highest soluble reducing sugar at 60.01 mg/ml in tamarind extract (pH 4/1% H2SO4 ) and highest weight loss of solids at 73.70% in tamarind extract (pH 2/1% H2SO4 /thermal 121°C). Aspergillus flavus performed better on tamarind extract (pH 2/1% H2SO4 ) by producing optimal CMCase and FPA activities at 0.100 U/ml and 0.409 U/ml respectively after 3 days of fermentation. Cellulase was maximally active at temperature of 50 °C. The tamarind extract pretreatment successfully proved to be an alternative organo-chemical pretreatment of sugarcane bagasse as evidenced by the physical properties, soluble reducing sugars and cellulase activities. Keywords: Aspergillus flavus, Cellulase, Pretreatment, Sugarcane bagasse, Tamarind extract

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21

Arif, Abdur Rahman, Andi Evi Erviani, Hasnah Natsir, Ilham Haidir e Maudy Audina Affandy. "Optimasi Pretreatment melalui Metode Hydrothermal Pressure dan Pelarut Alkali pada Produksi Bioetanol dari Lemna minor". ALCHEMY Jurnal Penelitian Kimia 14, n. 1 (15 febbraio 2018): 111. http://dx.doi.org/10.20961/alchemy.14.1.15986.111-123.

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Produk bioetanol dengan bahan dasar biomassa lignoselulosa perlahan banyak dikembangkan sebagai sumber energi alternatif. Tantangan utama dalam produksi lignoselulosa etanol berada pada tahap pretreatment. Pretreatment merupakan tahap yang memegang peranan penting dalam mendegradasi lignoselulosa menjadi selulosa. Pada penelitian ini digunakan Lemna minor yang merupakan gulma perairan dengan kombinasi dua tahap pretreatmen untuk melihat efektivitas degradasi lignoselulosa dalam sampel. Tahap pertama dengan metode hydrothermal pressure pada suhu pemanasan uap 121 ºC dan tekanan 15-20 psi dengan variasi waktu proses selama 5; 15; 30; 45; dan 60 menit. Tahap kedua pretreatment dengan metode kimiawi menggunakan NaOH dengan variasi konsentrasi 0,5; 1; 1,5; 2; dan 2,5 M. Hasil penelitian menunjukkan 60 menit merupakan waktu optimum dari metode hydrothermal pressure pada sampel Lemna minor dengan kadar lignin 11,32 %, kadar selulosa 17,39 %, kadar hemiselulosa 16,73 % dan kadar gula total 0,82 %. Untuk tahapan pretreatment dengan pelarut alkali (NaOH) kandungan kadar lignin Lemna minor setelah pretreatment dengan NaOH 2,0 M sebesar 5,36 %, kadar. Kandungan kadar selulosa, hemiselulosa dan gula total optimum diperoleh pada konsentrasi 2,5 M dengan nilai kadar 31,03 %; 5,57 % dan 1,74 %. Efektivitas penurunan kadar lignin pada pretreatment hydrothermal pressure sebesar 37,04 % sedangkan pretreatment dengan NaOH sebesar 70,18 %. Kombinasi proses pretreatment memberikan hasil yang cukup baik terhadap proses degradasi lignin yang terkandung dalam sampel Lemna minor sehingga sangat efektif digunakan dalam proses pembuatan bioetanol dengan bahan dasar biomassa. Bioethanol products with lignocellulosic biomass base ingredients have been developed as an alternative energy source. The main challenge in the production of lignocellulosic ethanol is on the pretreatment stage. Pretreatment is a stage that plays an important role in degrading lignocellulose into cellulose. In this study, we used a Lemna minor which is a water weed with a combination of two stages of pretreatmentt to see the effectiveness of lignocellulosic degradation in the sample. The first stage is hydrothermal pressure method of steam heating temperature 121 ºC and pressure 15-20 psi with variation of processing time for 5; 15; 30; 45; and 60 minutes. The second stage of pretreatment with chemical methods using NaOH with a concentration variation of 0.5; 1; 1.5; 2; and 2.5 M. The results showed that 60 minutes was the optimum time of the hydrothermal pressure method in the L.minor sample with the lignin level of 11.32 %, the cellulose 17.39 %, the hemicellulose 16.73 % and the total sugar 0.82 %. For the pretreatment stage with alkaline solvent (NaOH) the content of Lemna minor lignin after pretreatment with 2.0 M NaOH was 5.36 %. The content of cellulose, hemicellulose and total sugars was obtained at a concentration of 2.5 M with a grade value of 31.03 %; 5.57 % and 1.74 %. The effectiveness of lignin decrease in pretreatment hydrothermal pressure was 37.04 % while pretreatmentt with NaOH was 70.18 %. The combination of pretreatment process gives a good result to the lignin degradation process contained in the Lemna minor sample in order that it is very effective in the process of making bioethanol with biomass feedstock.

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22

Wang, Wen, Gang Luo, Li Xie e Qi Zhou. "Enhanced thermophilic fermentative hydrogen production from cassava stillage by chemical pretreatments". Water Science and Technology 68, n. 1 (1 luglio 2013): 59–67. http://dx.doi.org/10.2166/wst.2013.218.

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Acid and alkaline pretreatments for enhanced hydrogen production from cassava stillage were investigated in the present study. The result showed that acid pretreatment was suitable for enhancement of soluble carbohydrate while alkaline pretreatment stimulated more soluble total organic carbon production from cassava stillage. Acid pretreatment thereby has higher capacity to promote hydrogen production compared with alkaline pretreatment. Effects of pretreatment temperature, time and acid concentration on hydrogen production were also revealed by response surface methodology. The results showed that the increase of all factors increased the soluble carbohydrate production, whereas hydrogen production was inhibited when the factors exceeded their optimal values. The optimal conditions for hydrogen production were pretreatment temperature 89.5 °C, concentration 1.4% and time 69 min for the highest hydrogen production of 434 mL, 67% higher than raw cassava stillage.

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23

Shishesaz, Mohammad Reza, Moslem Ghobadi, Najmeh Asadi, Alireza Zarezadeh, Ehsan Saebnoori, Hamed Amraei, Jan Schubert e Ondrej Chocholaty. "Surface Pretreatments of AA5083 Aluminum Alloy with Enhanced Corrosion Protection for Cerium-Based Conversion Coatings Application: Combined Experimental and Computational Analysis". Molecules 26, n. 24 (7 dicembre 2021): 7413. http://dx.doi.org/10.3390/molecules26247413.

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The effects of surface pretreatments on the cerium-based conversion coating applied on an AA5083 aluminum alloy were investigated using a combination of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), polarization testing, and electrochemical impedance spectroscopy. Two steps of pretreatments containing acidic or alkaline solutions were applied to the surface to study the effects of surface pretreatments. Among the pretreated samples, the sample prepared by the pretreatment of the alkaline solution then acid washing presented higher corrosion protection (~3 orders of magnitude higher than the sample without pretreatment). This pretreatment provided a more active surface for the deposition of the cerium layer and provided a more suitable substrate for film formation, and made a more uniform film. The surface morphology of samples confirmed that the best surface coverage was presented by alkaline solution then acid washing pretreatment. The presence of cerium in the (EDS) analysis demonstrated that pretreatment with the alkaline solution then acid washing resulted in a higher deposition of the cerium layer on the aluminum surface. After selecting the best surface pretreatment, various deposition times of cerium baths were investigated. The best deposition time was achieved at 10 min, and after this critical time, a cracked film formed on the surface that could not be protective. The corrosion resistance of cerium-based conversion coatings obtained by electrochemical tests were used for training three computational techniques (artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine regression (SVMR)) based on Pretreatment-1 (acidic or alkaline cleaning: pH (1)), Pretreatment-2 (acidic or alkaline cleaning: pH (2)), and deposition time in the cerium bath as an input. Various statistical criteria showed that the ANFIS model (R2 = 0.99, MSE = 48.83, and MAE = 3.49) could forecast the corrosion behavior of a cerium-based conversion coating more accurately than other models. Finally, due to the robust performance of ANFIS in modeling, the effect of each parameter was studied.

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24

Orlando, Meneses-Quelal, e Velázquez-Martí Borja. "Pretreatment of Animal Manure Biomass to Improve Biogas Production: A Review". Energies 13, n. 14 (10 luglio 2020): 3573. http://dx.doi.org/10.3390/en13143573.

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The objective of this research is to present a review of the current technologies and pretreatments used in the fermentation of cow, pig and poultry manure. Pretreatment techniques were classified into physical, chemical, physicochemical, and biological groups. Various aspects of these different pretreatment approaches are discussed in this review. The advantages and disadvantages of its applicability are highlighted since the effects of pretreatments are complex and generally depend on the characteristics of the animal manure and the operational parameters. Biological pretreatments were shown to improve methane production from animal manure by 74%, chemical pretreatments by 45%, heat pretreatments by 41% and physical pretreatments by 30%. In general, pretreatments improve anaerobic digestion of the lignocellulosic content of animal manure and, therefore, increase methane yield.

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25

Gao, Ming, Juan Wang, Xiaoyu Ma, Na Song, Wenbin Zhu, Qunhui Wang e Chuanfu Wu. "Pretreatment of Sophora flavescens residues to produce fermentable sugars for lactic acid production: Optimization and mechanism analysis". BioResources 15, n. 2 (1 aprile 2020): 3636–50. http://dx.doi.org/10.15376/biores.15.2.3636-3650.

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The effects of three different pretreatments (H2SO4-heat, NaOH-heat, and hydrothermal pretreatment) on the enzymatic hydrolysis efficiency of Sophora flavescens residues (SFRs) were studied. After NaOH-heat pretreatment, the cellulose content of SFRs increased from 46.6% to 59.4%, and hydrolysis efficiency was 2.3 times higher than that of direct enzymatic hydrolysis without pretreatment. Moreover, the optimum pretreatment conditions were NaOH concentration of 1.00%, solid-liquid ratio of 1:10, temperature of 80 °C, and pretreatment time of 60 min. Under these conditions, 85.0% hydrolysis efficiency was obtained. When SFRs with NaOH-heat pretreatment were used as feedstocks in fermentation, the maximum lactic acid concentration was 33.7 g/L, which was twice that produced by SFRs without pretreatment. Mechanism analysis suggested that the lignin of SFRs was removed by NaOH solution, and the deacetylation reaction of hemicellulose occurred, which made the original smooth and dense structure become rough and loose, thus improving the accessibility of cellulose to enzymes.

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26

Dimitrellos, George, Gerasimos Lyberatos e Georgia Antonopoulou. "Does Acid Addition Improve Liquid Hot Water Pretreatment of Lignocellulosic Biomass towards Biohydrogen and Biogas Production?" Sustainability 12, n. 21 (27 ottobre 2020): 8935. http://dx.doi.org/10.3390/su12218935.

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The effect of liquid hot water (LHW) pretreatment with or without acid addition (A-LHW) on the production of hydrogen—through dark fermentation (DF)—and methane—through anaerobic digestion (AD)—using three different lignocellulosic biomass types (sunflower straw (SS), grass lawn (GL), and poplar sawdust (PS)) was investigated. Both pretreatment methods led to hemicellulose degradation, but A-LHW resulted in the release of more potential inhibitors (furans and acids) than the LHW pretreatment. Biological hydrogen production (BHP) of the cellulose-rich solid fractions obtained after LHW and A-LHW pretreatment was enhanced compared to the untreated substrates. Due to the release of inhibitory compounds, LHW pretreatment led to higher biochemical methane potential (BMP) than A-LHW pretreatment when both separated fractions (liquid and solid) obtained after pretreatments were used for AD. The recovered energy in the form of methane with LHW pretreatment was 8.4, 12.5, and 7.5 MJ/kg total solids (TS) for SS, GL, and PS, respectively.

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27

Paengkanya, Suwit, Surapit Tabtiang, Somkiat Prachayawarakorn e Somchart Soponronnarit. "Comparative Study of Effects of Hot Water and Steaming Blanching on Crisp Banana Qualities". ASEAN Journal of Scientific and Technological Reports 24, n. 1 (27 aprile 2021): 49–60. http://dx.doi.org/10.55164/ajstr.v24i1.241389.

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Abstract (sommario):

Crisp banana processed by hot air drying combined puffing provides low volumetric shrinkage and high crisp texture, but crisp product has more brown colour. The hot water blanching and steaming pretreatments could reduce brown colour of puffed product. From previous reports, the comparative study of effects of hot water blanching and steaming pretreatments on crisp banana qualities were limited. Therefore, this work was interested in a comparative study of the effects of hot water blanching and steaming pretreatments on crisp banana. The fresh bananas were cross sectional sliced to 2.5 mm and then they were pretreated by hot water or steaming. After that, it was dried by hot air and puffed by hot air. The experimental results showed that both pretreatments by hot water and steaming could reduce the firmness of raw material structure, resulting in the larger volumetric and lower hardness of pretretment product than that of the non-pretreatment banana product. In addition, the both pretreatment also retarded browning reaction of crisp banana product as compared to non-pretreatment product. However, it was not observed the difference in qualities of both pretreatment crisp banana methods. Increasing puffing temperature provided lower hardness of product, however, the color of puffed banana was more browning. Therefore, the banana should be pretreated by hot water blanching or steaming before processing and using of puffing temperature not exceeding 170 oC.

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28

de Oliveira, Maria C., Isabelli D. Bassin e Magali C. Cammarota. "Microalgae and Cyanobacteria Biomass Pretreatment Methods: A Comparative Analysis of Chemical and Thermochemical Pretreatment Methods Aimed at Methane Production". Fermentation 8, n. 10 (29 settembre 2022): 497. http://dx.doi.org/10.3390/fermentation8100497.

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Anaerobic digestion of microalgae and cyanobacteria was first proposed as a destination for algal biomass accumulated on stabilization ponds since it could not be disposed of directly in the environment. Now, the versatility of algal biomass makes them a suitable candidate to produce biofuels and other biomolecules in biorefineries. Anaerobic digestion of biomass is advantageous because it does not require the extraction of specific cellular constituents or drying of the biomass. Nevertheless, challenges remain regarding biomass concentration and their resistant cell walls, which are factors that could hamper methane yield. Many pretreatment methods, including chemical and thermochemical, have been proposed to break down the complex polymers present on the cell wall into smaller molecules. Unfortunately, the relationship between biomass solubilization and methane yield is not well defined. This article intends to review the anaerobic digestion of algal biomass and the role of chemical and thermochemical pretreatments in enhancing methane production. Several pretreatment conditions selected from the scientific literature were compared to verify which conditions actually improve methane yield. The severity of the selected pretreatments was also assessed using the combined severity factor. Results suggest that thermochemical pretreatment in less severe conditions is the most efficient, leading to a greater increase in methane yield. Only enzymatic pretreatments and some thermal pretreatments result in a positive energy balance. The large-scale implementation of pretreatment methods requires technological innovations to reduce energy consumption and its integration with other processes in wastewater treatment plants.

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29

Arif, Abdur Rahman, Andi Evi Erviani, Hasnah Natsir, Ilham Haidir e Maudy Audina Affandy. "Optimasi Pretreatment melalui Metode Hydrothermal Pressure dan Pelarut Alkali pada Produksi Bioetanol dari Lemna minor". ALCHEMY Jurnal Penelitian Kimia 14, n. 1 (15 febbraio 2018): 95. http://dx.doi.org/10.20961/alchemy.14.1.15986.95-106.

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Abstract (sommario):

Produk bioetanol dengan bahan dasar biomassa lignoselulosa perlahan banyak dikembangkan sebagai sumber energi alternatif. Tantangan utama dalam produksi lignoselulosa etanol berada pada tahap pretreatment. Pretreatment merupakan tahap yang memegang peranan penting dalam mendegradasi lignoselulosa menjadi selulosa. Pada penelitian ini digunakan Lemna minor yang merupakan gulma perairan dengan kombinasi dua tahap pretreatmen untuk melihat efektivitas degradasi lignoselulosa dalam sampel. Tahap pertama dengan metode hydrothermal pressure pada suhu pemanasan uap 121 °C dan tekanan 15-20 psi dengan variasi waktu proses selama 5, 15, 30, 45, dan 60 menit. Tahap kedua pretreatment dengan metode kimiawi menggunakan NaOH dengan variasi konsentrasi 0,5; 1; 1,5; 2; dan 2,5 M. Hasil penelitian menunjukkan 60 menit merupakan waktu optimum dari metode hydrothermal pressure pada sampel L. minor dengan kadar lignin 11,32%, kadar selulosa 17,39%, kadar hemiselulosa 16,73% dan kadar gula total 0,82%. Untuk tahapan pretreatment dengan pelarut alkali (NaOH) kandungan kadar lignin L. minor setelah pretreatment dengan NaOH 2,0 M sebesar 5,36%, kadar. Kandungan kadar selulosa, hemiselulosa dan gula total optimum diperoleh pada konsentrasi 2,5 M dengan nilai kadar 31,03%; 5,57% dan 1,74%. Efektivitas penurunan kadar lignin pada pretreatment hydrothermal pressure sebesar 37,04% sedangkan pretreatment dengan NaOH sebesar 70,18%. Kombinasi proses pretreatment memberikan hasil yang cukup baik terhadap proses degradasi lignin yang terkandung dalam sampel Lemna minor sehingga sangat efektif digunakan dalam proses pembuatan bioetanol dengan bahan dasar biomassa. Optimization Pretreatment through Hidrothermal Preassure and Alkaline Solvent Methods in Bioethanol Production from Lemna minor. Bioethanol products with lignocellulosic biomass feedstock have been developed as an alternative energy source. The main challenge in the production of lignocellulosic ethanol is on the pretreatment stage. Pretreatment is a stage that plays an important role in degrading lignocellulose into cellulose. In this study, we used a Lemna minor which is a water weed with a combination of two stages of pretreatmentt to see the effectiveness of lignocellulosic degradation in the sample. The first stage is hydrothermal pressure method of steam heating temperature 121 °C and pressure 15-20 psi with variation of processing time for 5, 15, 30, 45, and 60 minutes. The second stage of pretreatment with chemical methods using NaOH with a concentration variation of 0.5; 1; 1.5; 2 and 2.5 M. The results showed that 60 minutes was the optimum time of the hydrothermal pressure method in the L. minor sample with the lignin content of 11.32%, the cellulose 17.39%, the hemicellulose 16.73% and the total sugar 0.82%. For the pretreatment stage with alkaline solvent (NaOH) the content of L. minor lignin after pretreatment with 2.0 M NaOH was 5.36%. The content of cellulose, hemicellulose and total sugars was obtained at a concentration of 2.5 M with a grade value of 31.03%, 5.57%, and 1.74%. The effectiveness of lignin decrease in pretreatment hydrothermal pressure was 37.04% while pretreatmentt with NaOH was 70.18%. The combination of pretreatment process gives a good result to the lignin degradation process contained in the L. minor sample in order that it is very effective in the process of making bioethanol with biomass feedstock.

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30

Zhong, Weixin, Hongbo Yu, Lili Song e Xiaoyu Zhang. "Combined pretreatment with white-rot fungus and alkali at near room-temperature for improving saccharificaiton of corn stalks". BioResources 6, n. 3 (26 luglio 2011): 3440–51. http://dx.doi.org/10.15376/biores.6.3.3440-3451.

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Abstract (sommario):

Although biological pretreatment has the advantages of being environmentally friendly and having low-energy consumption, it usually requires a relatively long incubation time. In this study, a novel combined pretreatment with white-rot fungus and alkali at near room-temperature for saccharification of corn stalks was investigated to speed up the biological process. Biological pretreatment with Irpex lacteus or Echinodontium taxodii can improve enzymatic hydrolysis of corn stalk greatly, but the process requires a long time (60 days) to achieve a satisfactory sugar yield. The combination processes with the fungi were compared with the sole pretreatments. The results showed that the time of the biological process could be shortened to 15 days when the bio-treatment with I. lacteus was combined with alkali pretreatment. The efficiency of alkali pretreatment can be also enhanced significantly by biological treatment. 271.1mg/g of final glucose yield was obtained for the combination pretreatment, which was an improvement of 50.4% and 28.3% in comparison with the sole alkali pretreatment at the same and optimum reaction time, respectively. In conclusion, the combination of biological pretreatment with alkali processes not only speeded up the biological process, but also improved the sugar yield in comparison to the sole pretreatment and is favorable for the development of biological pretreatment.

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31

He, Wenting, Weiming Guo e Zhongchun Jiang*. "Effects of Ultrasonic Wave on Water Conditions, Antioxidases, and Free Radical in Cut Nymphaea tetragona During Cold Wet Storage". HortScience 39, n. 4 (luglio 2004): 760B—760. http://dx.doi.org/10.21273/hortsci.39.4.760b.

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Effects of two pretreatments, i.e., ultrasonic wave (UW) and ultrasonic wave plus preservative solution (UW+PS), on water conditions of flower stem and membrane stability of petals in Nymphaea tetragona during 6-d cold wet storage. Compared with no pretreatment control, the two pretreatments prolonged the vase life and improved water conditions of the cut flower during cold storage to different degrees. Fresh weight of flower stems and relative water content of petals increased during cold storage. The water utilization efficiency of flower stem and water potential in different parts of flower stem were improved significantly as a result of the pretreatments. Although both pretreatments helped the cut flowers maintain favorable water relations, the effects of UW + PS combined pretreatment were better than UW pretreatment alone. In addition, UW and UW+PS inhibited the increase in the contents of lipid peroxidation product malondialdehyde (MDA) and superoxide anion in petals. UW + PS promoted superoxide dismutase (SOD) and catalase (CAT) activities in petals during cold storage to a greater degree than did UW.

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32

MANOKHOON, PITIPORN, KHATHAPON PINPATTHANAPONG, NITHINART C. JUNTADECH e THANEEYA RANGSEESURIYACHAI. "EFFECTS OF COMBINED CHEMICAL AND HYDROTHERMAL PRETREATMENT ON PAPYRUS CELLULOSE STRUCTURE". Cellulose Chemistry and Technology 57, n. 9-10 (15 dicembre 2023): 1041–51. http://dx.doi.org/10.35812/cellulosechemtechnol.2023.57.92.

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Abstract (sommario):

"Papyrus (Cyperus papyrus L.) is a lignocellulosic plant suitable for many applications when properly pretreated. This study explores the potential of a two-stage pretreatment (combining hydrothermal and chemical methods) on the characteristics of cellulose fibers derived from papyrus. One-stage and two-stage pretreatments were compared, utilizing sodium hydroxide (NaOH) and ferric chloride (FeCl3) chemical solutions at a 3% (w/v) concentration. Chemical pretreatment was employed for one-stage processing, while hydrothermal pretreatment was introduced prior to chemical pretreatment. As the liquid hot-water process intensified, significant changes in chemical composition and morphology occurred. Hydrothermal pretreatment partially eliminates hemicelluloses and lignin, while increasing the cellulose content and enhancing fiber crystallinity. Following the pulping and bleaching stages, it was determined that the FeCl3-based two-stage pretreatment exhibited the greatest potential for cellulose recovery and hemicelluloses and lignin removal, yielding the highest crystallinity index."

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33

Widiyati, Nova Ellya, Iffah Muflihati, Rini Umiyati e Arief Rakhman Affandi. "Pretreatment of Aloe Vera and Its Effect on the Properties of Flour and Vermicelli Produced". Jurnal Berkala Ilmiah Sains dan Terapan Kimia 17, n. 2 (23 ottobre 2023): 22. http://dx.doi.org/10.20527/jstk.v17i2.14900.

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Abstract (sommario):

Aloe vera powder has a less bright color due to the browning reaction. Pretreatment was carried out to improve the quality of aloe vera flour. Aloe vera flour can be used to manufacture food products, one of which is vermicelli. This study aimed to determine the effect of different pretreatments, namely blanching, sodium metabisulfite immersion, sodium bisulfite immersion, and steam blanching, on the characteristics of aloe vera flour and its application to vermicelli. The research steps included aloe vera pretreatment and aloe vera flour production, vermicelli production with aloe vera flour substitution, and analysis. The results showed that the pretreatment produced aloe vera and vermicelli flour with a brighter color. Pretreatment also affects water content, water-holding capacity, oil-holding capacity, and cooking properties. But the pretreatment did not affect the sensory properties of vermicelli.

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34

Boontian, Nittaya, Thunchanok Phorndon, Chatlada Piasai e Mohamad Padri. "Combination of Alkaline and Heat Pretreatments with Zero-Valent Iron Application in Cassava Pulp and Wastewater for Methane Generation: Development from Batch to Continuous Systems". Fermentation 9, n. 2 (23 gennaio 2023): 108. http://dx.doi.org/10.3390/fermentation9020108.

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Abstract (sommario):

Pretreatment with the addition of metals to anaerobic digestion in biogas production is crucial to address improper degradation of organic compounds with low methane production. Biogas production from a combination of cassava pulp and cassava wastewater in the batch system under the variation of alkaline and heat conditions as a pretreatment was investigated with the zero-valent iron (ZVI) addition after the pretreatment. It was found that alkaline pretreatment at pH 10 with the heat at 100 °C for 30 min combined with 50 g of ZVI kg of TVS−1 showed the highest methane production up to 4.18 m3 CH4 kg TVS−1. Nevertheless, chemical oxygen demand (COD) and volatile fatty acid (VFA) removals were slightly reduced when ZVI was added to the system. Furthermore, application in the continuous system showed increased COD and VFA removals after applying alkaline and heat pretreatments. On the other hand, additional ZVI in the substrate after the pretreatments in the continuous system increased the methane production from 0.58 to 0.90 and 0.19 to 0.24 of CH4 m3 kg TVS−1 in 20 and 60 days of hydraulic retention times (HRTs), respectively. Thus, a suitable combination of alkaline and heat pretreatments with ZVI is essential for increasing methane production in batch and continuous systems.

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35

Galal Shams El-Din, Nihal, Nayrah A. Shaltout, Mustafa A. Ghazal, Alaa E. Ali e Doha M. Beltagy. "PHYSICAL PRETREATMENT OF ULVA FASCIATA FOR ENHANCINGBIODIESEL PRODUCTION AND QUALITY". International Journal of Advanced Research 9, n. 03 (31 marzo 2021): 347–63. http://dx.doi.org/10.21474/ijar01/12591.

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Abstract (sommario):

The green algae Ulva faciata was subjected to different physical pretreatments comprising thermal and mechanical techniques at different experimental conditions to state the most appropriate method of cell disruption for increasing the quantity of the extracted lipid and hence improve the quality of the produced biodiesel with low cost. Thermal pretreatment was autoclaving of either wet or dry algal biomass, while mechanical pretreatments include microwave and ultrasonication at different time intervals. The control was the alga without pretreatment extracted at optimum conditions: 60 min, 55oC, shaking speed at 250 rpm, < 0.16 mm particle size with 25:1 v/w solvent to solid ratio. The results showed that the quantity of extracted lipids in case of using all physical pretreatments increased the Total fatty acids yield significantly by about 2-folds of the control for wet algae in hydrothermal treatment with optimum time of treatment 40 minutes, and 1.4 folds for dry algae in thermal pretreatment of the dried alga for 60minutes autoclaving period. The sharp increase by 2.2 folds of extracted lipids was recorded by microwave pretreatment for radiation period (5 min), while ultrasonication showed 2.1-fold increase in lipid yield at 15minutes ultrasound exposure time. Concerning the physical properties of the produced biodiesel after all physical pretreatments, the results indicated that the produced biodiesel had very high quality as all its properties are almost complied with the ASTM D6751 and EN14214 standards. These results were confirmed statistically where all physical pretreatments had high significant effect on fatty acids yield and Biodiesel properties.

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36

Wang, Xiujun, Deliang Fan, Yutong Han e Jifei Xu. "Multivariable Analysis Reveals the Key Variables Related to Lignocellulosic Biomass Type and Pretreatment before Enzymolysis". Catalysts 12, n. 10 (29 settembre 2022): 1142. http://dx.doi.org/10.3390/catal12101142.

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In this study, partial least square (PLS), a multivariable analysis, was used to simultaneously quantitatively evaluate the effects of variables related to three pretreatments (alkaline, hot water and acid) and the biomass properties of poplar, salix and corncob. The results showed that biomass type was the most important variable influencing enzymolysis reducing sugar yield (ERSY). The biomass compositions affected the ERSY more than the pretreatment conditions, among which hemicellulose and lignin played vital roles. The alkaline pretreatment had a more positive effect on the ERSY than the acid and hot water pretreatments, in which alkaline content had more influence than temperature. This work provides a deeper understanding of the material properties and the pretreatment conditions in different complex systems before enzymolysis, which might be a guidance to future study.

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37

Niño López, Lilibeth, Alejandro Acosta Cárdenas e Ricardo Gelves Zambrano. "Evaluation of chemical pretreatments for enzymatic hydrolysis of lignocellulosic residues cassava (Manihot esculenta Crantz)". Revista Facultad de Ingeniería Universidad de Antioquia, n. 69 (20 gennaio 2014): 317–26. http://dx.doi.org/10.17533/udea.redin.18158.

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The effect of different chemical pretreatment with sulfuric acid (H2SO4), sodium hydroxide (NaOH) and hydrogen peroxide (H2O2) were evaluated by quantifying total reducing sugars produced during enzymatic hydrolysis step of lignocellulosic residues cassava (Manihot esculenta Crantz) and lignin removal percentage after pretreatment. The amount of waste used (1 to 5%) (w/v) in different particle sizes (1.18 and 0.6 mm) were pretreated separately (leaves and stems) with H2SO4, NaOH and H2O2 at varying concentrations (1 and 5%) (w/v). Plant residues were hydrolyzed with enzyme Accellerase 1500 with 50 ° C, pH 5 and 140 rpm. NaOH pretreatment enables higher total reducing sugars released during enzymatic hydrolysis (3.7 g/L) followed by leave pretreatments using H2SO4 (2.11 g/L) and H2O2 (1.54 g/L). Sugar concentrations were lower in stem pretreatments.

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38

Hren, Robert, Aleksandra Petrovič, Lidija Čuček e Marjana Simonič. "Determination of Various Parameters during Thermal and Biological Pretreatment of Waste Materials". Energies 13, n. 9 (4 maggio 2020): 2262. http://dx.doi.org/10.3390/en13092262.

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Pretreatment of waste materials could help in more efficient waste management. Various pretreatment methods exist, each one having its own advantages and disadvantages. Moreover, a certain pretreatment technique might be efficient and economical for one feedstock while not for another. Thus, it is important to analyze how parameters change during pretreatment. In this study, two different pretreatment techniques were applied: thermal at lower and higher temperatures (38.6 °C and 80 °C) and biological, using cattle rumen fluid at ruminal temperature (≈38.6 °C). Two different feedstock materials were chosen: sewage sludge and riverbank grass (Typha latifolia), and their combinations (in a ratio of 1:1) were also analyzed. Various parameters were analyzed in the liquid phase before and after pretreatment, and in the gas phase after pretreatment. In the liquid phase, some of the parameters that are relevant to water quality were measured, while in the gas phase composition of biogas was measured. The results showed that most of the parameters significantly changed during pretreatments and that lower temperature thermal and/or biological treatment of grass and sludge is suggested for further applications.

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39

Hamonangan Panjaitan, Jabosar Ronggur, e Misri Gozan. "TECHNO-ECONOMIC EVALUATION OF NITROCELLULOSE PRODUCTION FROM PALM OIL EMPTY FRUIT BUNCHES". ASEAN Engineering Journal 11, n. 4 (28 novembre 2021): 246–54. http://dx.doi.org/10.11113/aej.v11.18037.

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Nitrocellulose is a cellulose derivative that has many potential applications. Nitrocellulose can bemade through nitration reactions by reacting cellulose and nitric acid at low temperatures. Cellulose can be obtained from lignocellulose biomass such as palm oil empty fruit bunches (POEFBs). In this study, techno-economic evaluation of nitrocellulose production from POEFBs was investigated with various types of alkaline and acid pretreatments. Pretreatment of POEFBs with alkaline and acid was used to purify cellulose fraction as raw material for nitrocellulose. The combination process of POEFBs pretreatment with alkaline and acid can be classified into 4 process routes such as ammonium hydroxide and sulfuric acid pretreatment (Route-1), ammonium hydroxide and acetic acid pretreatment (Route-2), sodium hydroxide and sulfuric acid pretreatment (Route-3), and sodium hydroxide and acetic acid pretreatment (Route-4). The results showed that ammonium hydroxide and sulfuric acid pretreatment (Route-1) was the most profitable route to produce nitrocellulose. Economic parameter values such as return of investment (ROI), payback period (PBP), net present value (NPV) and internal rate of return (IRR) from ammonium hydroxide and sulfuric acid pretreatment (Route-1) were 11.49%, 5.85 years, US$ 442,427 and 13.35%.

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Nkemka, Valentine Nkongndem, Yongqiang Li e Xiying Hao. "Effect of thermal and alkaline pretreatment of giant miscanthus and Chinese fountaingrass on biogas production". Water Science and Technology 73, n. 4 (29 ottobre 2015): 849–56. http://dx.doi.org/10.2166/wst.2015.559.

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Giant miscanthus (Miscanthus×giganteus) and Chinese fountaingrass (Pennisetum alopecuroides (L.) Spreng), cultivated for landscaping and soil conservation, are potential energy crops. The study investigated the effect of combined thermal and alkaline pretreatments on biogas production of these energy crops. The pretreatment included two types of alkali (6% CaO and 6% NaOH) at 22, 70 and 100 °C. The alkaline pretreatment resulted in a greater breakdown of the hemicellulose fraction, with CaO more effective than NaOH. Pretreatment of giant miscanthus with 6% CaO at 100 °C for 24 h produced a CH4 yield (313 mL g−1 volatile solids (VS)) that was 1.7 times that of the untreated sample (186 mL g−1 VS). However, pretreatment of Chinese fountaingrass with 6% CaO or 6% NaOH at 70 °C for 24 h resulted in similar CH4 yields (328 and 302 mL g−1 VS for CaO and NaOH pretreatments) as the untreated sample (311 mL g−1 VS). Chinese fountaingrass was more easily digestible but had a low overall CH4 yield per hectare (1,831 m3 ha−1 y−1) compared to giant miscanthus (6,868 m3 ha−1 y−1). This study demonstrates the potential of thermal/alkaline pretreatment and the use of giant miscanthus and Chinese fountaingrass for biogas production.

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Zahoor, Wen Wang, Xuesong Tan, Qiang Yu, Yongming Sun, Zhenhong Yuan, Kyoungseon Min, Jinsuk Lee, Zi Shang Bai e Xinshu Zhuang. "Comparison of Low-Temperature Alkali/Urea Pretreatments for Ethanol Production from Wheat Straw". Journal of Biobased Materials and Bioenergy 15, n. 3 (1 giugno 2021): 399–407. http://dx.doi.org/10.1166/jbmb.2021.2062.

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NaOH/urea (NU) pretreatment at lower than 0 °C has been frequently applied for improving bio-conversion of lignocellulose, but the wastewater generated from the pretreatment process is hard to dispose. KOH/urea (KU) pretreatment for enhancing bioconversion of lignocellulose has recently attracted researchers’ attention due to the recycling of wastewater for facilitating crops’ growth. This study compared the effects of NU and KU pretreatments at cold conditions on the enzymatic hydrolysis and bioethanol yield from wheat straw (WS). By using response surface methodology an optimal pretreatment with an equal ratio of alkali/urea (4% w/v) at −20 °C for 3 h was established. The enzymatic hydrolysis of KU-treated WS was 81.17%, which was similar to that of NU-treated WS (83.72%) under the same condition. It means that KU pretreatment has equal ability to NU pretreatment to improve enzymatic saccharification of lignocellulose. KU pretreatment has the promising potential to replace NU pretreatment for facilitating bioconversion of lignocellulose in cold conditions due to the clean way to recycle its wastewater as fertilizer for crop growth. Hence, KU pretreatment combined with enzymatic hydrolysis and fermentation could be a promising green way to cellulosic ethanol production with zero waste emission.

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42

Edmunds, Charles W., Perry Peralta, Ratna R. Sharma-Shivappa, Stephen S. Kelley, Vincent L. Chiang, Zachary D. Miller, Richard L. Giles et al. "Fungal pretreatment and enzymatic hydrolysis of genetically-modified Populus trichocarpa". BioResources 15, n. 3 (6 luglio 2020): 6488–505. http://dx.doi.org/10.15376/biores.15.3.6488-6505.

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Fungal pretreatment of Populus trichocarpa wood genetically modified to reduce lignin and alter lignin chemistry is investigated for its effectiveness as an alternative to common pretreatment methods. The goal of this work is to improve biomass utilization for biofuel and biochemical applications by increasing sugar release. Sugar release after enzymatic hydrolysis was measured after various biomass pretreatments (including wood-rot fungus, hot water, and dilute acid). In the wildtype, and in constructs downregulated in PAL, 4CL, and C3H, the fungal pretreatment resulted in substantial improvements in sugar yields, up to 2.4-fold increase in glucose yield and 6-fold increase in xylose yield after enzymatic hydrolysis compared to the unpretreated control. However, the effects of fungal pretreatment were inconsistent, and in genetic lines down-regulated in 4CL, CCoAOMT, CAld5H, and C3H, fungal pretreatment yielded similar or decreased sugar release after enzymatic hydrolysis.

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43

Edmunds, Charles W., Perry Peralta, Ratna R. Sharma-Shivappa, Stephen S. Kelley, Vincent L. Chiang, Zachary D. Miller, Richard L. Giles et al. "Fungal Pretreatment and Enzymatic Hydrolysis of Genetically-modified Populus trichocarpa". BioResources 15, n. 3 (6 luglio 2020): 6488–505. http://dx.doi.org/10.15376/biores.15.3.6488-6506.

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Abstract (sommario):

Fungal pretreatment of Populus trichocarpa wood genetically modified to reduce lignin and alter lignin chemistry is investigated for its effectiveness as an alternative to common pretreatment methods. The goal of this work is to improve biomass utilization for biofuel and biochemical applications by increasing sugar release. Sugar release after enzymatic hydrolysis was measured after various biomass pretreatments (including wood-rot fungus, hot water, and dilute acid). In the wildtype, and in constructs downregulated in PAL, 4CL, and C3H, the fungal pretreatment resulted in substantial improvements in sugar yields, up to 2.4-fold increase in glucose yield and 6-fold increase in xylose yield after enzymatic hydrolysis compared to the unpretreated control. However, the effects of fungal pretreatment were inconsistent, and in genetic lines down-regulated in 4CL, CCoAOMT, CAld5H, and C3H, fungal pretreatment yielded similar or decreased sugar release after enzymatic hydrolysis.

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44

Yu, Qun, e Kun Zhang. "Experimental Study on the Effect of Different Pretreatment Methods on Rubber Concrete Work Performance and Compressive Strength". Applied Mechanics and Materials 507 (gennaio 2014): 421–24. http://dx.doi.org/10.4028/www.scientific.net/amm.507.421.

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In untreated, clean water, NaOH solution to clean, CCl4 solution to clean the rubber particles of different pretreatments as the main influencing factors, by 51 rubber concrete block pilot study reached different pretreatment methods on different rubber particle size and dosage of rubber concrete workability and compressive strength were investigated. The results show that: water, NaOH solution, CCl4 pretreatment solution, such as a rubber concrete workability and compressive strength were improved, and the rubber particles larger pretreatment on rubber compressive strength of concrete work to improve performance and more obvious.

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45

Li, Qiang, Xu Ding Gu, Geng Sheng Ji, Juan Juan Fei, Yuan Yuan Feng e You Ting Wu. "Ionic Liquid 1-Ethyl-3-Methylpyridinium Diethyl Phosphate Pretreatment of Mulberry Residue". Applied Mechanics and Materials 253-255 (dicembre 2012): 777–80. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.777.

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The IL 1-ethyl-3-methylpyridinium diethyl phosphate ([EPyM][EMP]) and 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) were compared in view of thier superority in pretreatment toward accelerating enzymatic hydrolysis of cellulosic biomass, and they could be recyclable. Efficient ionic liquid pretreatments of cellulose can be obtained with short duration times (20 min) at 50-120 °C with [EPyM][EMP] and [EMIM]OAc. And [EPyM][EMP] showed preferable cellulosic biomass pretreatment capability. The short time and mild temperature of cellulose solubilization allowed a in situ processing of [EPyM][EMP] IL-pretreatment and saccharification.

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46

Varrone, Cristiano, Lei Zhao, Guang Li Cao, Tao Sheng, Nan Qi Ren e Ai Jie Wang. "Comparison of Different Pretreatment Methods to Increase Hydrogen Production from Cornstalk". Advanced Materials Research 724-725 (agosto 2013): 216–21. http://dx.doi.org/10.4028/www.scientific.net/amr.724-725.216.

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Lignocellulosic biomass can be an ideal feedstock for fermentative hydrogen production if properly pretreated and hydrolyzed. In this research, to enhance hydrogen production from cornstalk, acid and alkali pretreatments were performed. Alkali pretreatment was conducted at 80°C for 60 min and room temperature for 7 days with the addition of 4% NaOH; acid pretreatments at 190°C, and 120°C for 10 min and 120 min, respectively, with the addition of 1.7% H2SO4. All the chemical components change of the substrates was detected. The highest lignin reduction of 75.6%, compared to untreated samples, was found at 80°C with 4% NaOH dosage. Under this pretreatment condition, highest increase in reducing sugar and hydrogen yield (up to 11.8 g/L and 71.8 ml/g-pretreated cornstalk) was obtained. The present results suggested an efficient pretreatment method to increase hydrogen production from lignocellulosic biomass.

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47

Novia, Novia, Hasanudin Hasanudin, Hermansyah Hermansyah e Ahmad Fudholi. "Kinetics of Lignin Removal from Rice Husk Using Hydrogen Peroxide and Combined Hydrogen Peroxide–Aqueous Ammonia Pretreatments". Fermentation 8, n. 4 (1 aprile 2022): 157. http://dx.doi.org/10.3390/fermentation8040157.

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The rice husk has the potential to be used for converting agricultural wastes into renewable energy. Therefore, this study aims to improve the hydrolysis of rice husk through Hydrogen Peroxide (HP) and Combined Hydrogen Peroxide–Aqueous Ammonia (CHPA) pretreatments. The removal of lignin from rice husks was determined using SEM–EDS examination of the samples. At a specific concentration of H2O2, (CHPA) pretreatment eliminated a significantly larger amount of lignin from biomass. The percentage of lignin removal of HP varied from 48.25 to 66.50, while CHPA ranged from 72.22 to 85.73. Hence, the use of batch kinetics of lignin removal of both pretreatments is recommended, where the kinetic parameters are determined by fitting the experimental data. Based on the results, the activation energies for HP and CHPA pretreatments were 9.96 and 7.44 kJ/mol, which showed that the24 model is appropriate for the experimental data. The increase in temperatures also led to a higher pretreatment value, indicating their positive correlation. Meanwhile, CHPA pretreatment was subjected to enzymatic hydrolysis of 6% enzyme loading for the production of 6.58 g glucose/L at 25 h.

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Novia, Novia, Vishnu K. Pareek, Hermansyah Hermansyah e Asyeni Miftahul Jannah. "Effect of Dilute Acid - Alkaline Pretreatment on Rice Husk Composition and Hydrodynamic Modeling with CFD". Science and Technology Indonesia 4, n. 1 (27 gennaio 2019): 18. http://dx.doi.org/10.26554/sti.2019.4.1.18-23.

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The high cellulosic content of rice husk can be utilized as a feedstock for pulp and biofuel. Pretreatment is necessary to break the bonds in the complex lignocellulose matrices addressing the cellulose access. This work aims to utilize the rice husk using dilute acid and alkaline pretreatment experimentally and CFD modeling. The study consists of three series of research. The first stage was the dilute acid pretreatment with sulfuric acid concentration of 1% to 5% (v/v) at 85°C for 60 minutes, and alkaline pretreatment with NaOH concentration of 1% to 5% (w/v) at 85oC for 30 minutes separately. The second stage used the combination of both pretreatment. Moreover the last stage of research was hydrodynamic modeling of pretreatment process by CFD (ANSYS FLUENT 16). The experimental results showed that the lowest lignin content after acid pretreatment was about 10.74%. Alkaline pretreatment produced the lowest lignin content of 4.35%. The highest cellulose content was 66.75 % for acid-alkaline pretreatment. The lowest content of lignin was about 6.09% for acid-alkaline pretreatment. The lowest performance of alkaline pretreatment on HWS (hot water solubility) of about 7.34% can be enhanced to 9.71% by using a combination alkaline-acid. The combined pretreatments result hemicellulose of about 9.59% (alkaline-acid) and 9.27% (acid-alkaline). Modeling results showed that the mixing area had the minimum pressure of about -6250 Pa which is vortex leading minimum efficiency of mixing. The rice husk flowed upward to the upper level and mixed with reagent in the perfect mixing.

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49

Li, Hui Yong, Ke Long Huang, Mi Jin, Qin Qin Wei e Zhi Guang Li. "Effect of Two Mild Alkaline Oxidative Pretreaments of Rice Straw on Enzymatic Hydrolysis". Advanced Materials Research 396-398 (novembre 2011): 1636–39. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.1636.

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Two mild alkaline oxidative pretreatments of rice straw followed by enzymatic hydrolysis were investigated. In addition to measuring the composition variance, the pretreated rice straw solutions were analysed by the UV/Vis spectra. These two mild oxidative pretreatment of rice straw cause the removal of lignin, hemicellulose and neutral detergent solubles (NDS), where the H2O2/NaOH pretreatment solubilize the lignin and the O3/NaOH pretreatment oxidative degrade the lignin. These two mild oxidative pretreatment of rice straw enhance susceptibility to enzymatic hydrolysis, and speed-up the enzymatic hydrolysis. The conversion yield of cellulose and hemicellulose presented in the O3/NaOH pretreated rice straw was 92.6%, compared to 82.3% and 52.5% in the H2O2/NaOH pretreated and untreated rice straw, respectively.

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Cai, Hong, Yi Bo Wen e Ji Li. "Effect of Composting, Leaching and Carbonizing on Alleviating Phytotoxicity of Sewage Sludge". Advanced Materials Research 518-523 (maggio 2012): 1733–36. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.1733.

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Sewage sludge (SS) contains deleterious constituents that strongly inhibited seed germination. Pretreatment methods of composting, leaching and carbonizing were thus evaluated to alleviate the phytotoxicity. All the pretreatments improved germination rate, root length and germination index of radish seeds. The best performances were presented by composting pretreatment and the pretreatment of carbonizing plus leaching. Composting greatly alleviated phytotoxicity of SS and improved seed germination, however, it also showed stunted root length and germination index compared with the soil control. The adverse effects of composted SS on seed germination were completely eliminated by leaching, while carbonizing had little effect on reversing the stunt. These results indicated that the most effective pretreatment method to alleviate phytotoxicity of SS were composting plus leaching.

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