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1.
Int J Biol Macromol ; 259(Pt 2): 129140, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38199558

RESUMEN

Plastic wastes accumulated due to food packaging pose environmental threats. This study proposes biopolymeric films containing lignins extracted from potato crop residues (PCR) through organosolv treatment as a green alternative to non-degradable food packaging. The isolation process yielded 43.9 wt% lignins with a recovery rate of 73.5 wt% achieved under optimum conditions at 180 °C with 50 % v/v ethanol. The extracted lignins were then incorporated into a starch matrix to create biocomposite films. ATR-FTIR analysis confirmed interactions between the starch matrix and extracted lignins, and XRD analysis showed the amorphous structure of lignins, reducing film crystallinity. The addition of 1 wt% of extracted lignins resulted in a 87 % reduction in oxygen permeability, a 25 % increase in the thermal stability of the film, and a 78 % enhancement in antioxidant. Furthermore, introducing 3 wt% lignins led to the lowest water vapor transmission rate, measuring 9.3 × 10-7 kg/s·m2. Morphological studies of the films demonstrated a homogeneous and continuous structure on both the surface and cross-sectional areas when the lignins content was below 7 wt%. These findings highlight the potential of using organosolv lignins derived from potato crop residues as a promising additive for developing eco-friendly films designed for sustainable food packaging.


Asunto(s)
Lignina , Solanum tuberosum , Lignina/química , Solanum tuberosum/química , Almidón/química , Embalaje de Alimentos , Antioxidantes/química
2.
Sci Total Environ ; 912: 168733, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38013097

RESUMEN

A novel third-generation biorefinery approach, including two paths of Ethanol/methane production pathway (EMP) and the direct methane production pathway (DMP), for astaxanthin and ethanol and biogas production from the freshwater microalgae Haematococcus pluvialis was developed previously. To ensure its environmental sustainability, a comprehensive life cycle assessment (LCA) study was conducted based on 1-GJ energy generation from biomethane as the functional unit. Results indicate that the EMP pathway had higher environmental impacts on all categories due to more stages and chemicals/energy consumption (at least five times greater effect). Results showed that while the enzymatic hydrolysis step followed by the fermentation stage was the main contributor to all environmental categories in the EMP route, astaxanthin induction dominated all environmental categories in the DMP route. The results showed that sodium nitrate, phosphate salts, inoculum sludge, acetone, and electricity had considerable environmental impacts. Moreover, despite low enzyme usage in enzymatic hydrolysis, these proteins significantly impacted all environmental categories in this stage. The baseline analysis concluded that to produce 1 GJ energy from methane, about 88 kg and 13 kg CO2 were generated from the EMP and DMP pathways, respectively. A sensitivity analysis was also conducted to compare various ratios of chemicals, such as phosphate salts, with high contributions to enzymatic hydrolysis and astaxanthin induction stages in the EMP and DMP routes, respectively. Finally, the LCA results revealed that the DMP pathway is more environmentally friendly with the same economic value of biomethane and astaxanthin production. This LCA study updated the data related to the environmental assessment of processes to utilize H. pluvialis to produce biofuels and astaxanthin simultaneously.


Asunto(s)
Biocombustibles , Sales (Química) , Ambiente , Etanol , Metano , Fosfatos , Xantófilas
3.
Sci Total Environ ; 899: 165751, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37499830

RESUMEN

Life cycle assessment was used to evaluate the environmental impacts of phytoplanktonic biofuels as possible sustainable alternatives to fossil fuels. Three scenarios were examined for converting planktonic biomass into higher-value commodities and energy streams using the alga Scenedesmus sp. and the cyanobacterium Arthrospira sp. as the species of interest. The first scenario (Sc-1) involved the production of biodiesel and glycerol from the planktonic biomass. In the second scenario (Sc-2), biodiesel and glycerol were generated from the planktonic biomass, and biogas was produced from the residual biomass. The process also involved using a catalyst derived from snail shells for biodiesel production. The third scenario (Sc-3) was similar to Sc-2 but converted CO2 from the biogas upgrading to methanol, which was then used in synthesizing biodiesel. The results indicated that Sc-2 and Sc-3 had a reduced potential (up to 60 % less) for damaging human health compared to Sc-1. Sc-2 and Sc-3 had up to 61 % less environmental impact than Sc-1. Sc-2 and Sc-3 reduced the total cumulative exergy demand by up to 44 % compared to Sc-1. In conclusion, producing chemicals and utilities within the biorefinery could significantly improve environmental sustainability, reduce waste, and diversify revenue streams.


Asunto(s)
Biocombustibles , Fitoplancton , Humanos , Glicerol , Combustibles Fósiles , Ambiente , Biomasa , Plancton
4.
Bioresour Technol ; 384: 129370, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37343805

RESUMEN

This work aimed to study an integrated pretreatment technology employing p-toluenesulfonic acid (TsOH)-catalyzed liquid hot water (LHW) and short-time ball milling for the complete conversion of poplar biomass to xylooligosaccharides (XOS), glucose, and native-like lignin. The optimized TsOH-catalyzed LHW pretreatment solubilized 98.5% of hemicellulose at 160 °C for 40 min, releasing 49.8% XOS. Moreover, subsequent ball milling (20 min) maximized the enzymatic hydrolysis of cellulose from 65.8% to 96.5%, owing to the reduced particle sizes and cellulose crystallinity index. The combined pretreatment reduced the crystallinity by 70.9% while enlarging the average pore size and pore volume of the substrate by 29.5% and 52.4%, respectively. The residual lignin after enzymatic hydrolysis was rich in ß-O-4 linkages (55.7/100 Ar) with less condensed structures. This lignin exhibited excellent antioxidant activity (RSI of 66.22) and ultraviolet absorbance. Thus, this research suggested a sustainable waste-free biorefinery for the holistic valorization of biomass through two-step biomass fractionation.


Asunto(s)
Lignina , Populus , Lignina/química , Glucosa , Biomasa , Celulosa/química , Hidrólisis , Agua/química , Catálisis
5.
Compr Rev Food Sci Food Saf ; 22(5): 4147-4185, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37350102

RESUMEN

The development of biodegradable packaging is a challenge, as conventional plastics have many advantages in terms of high flexibility, transparency, low cost, strong mechanical characteristics, and high resistance to heat compared with most biodegradable plastics. The quality of biodegradable materials and the research needed for their improvement for meat packaging were critically evaluated in this study. In terms of sustainability, biodegradable packagings are more sustainable than conventional plastics; however, most of them contain unsustainable chemical additives. Cellulose showed a high potential for meat preservation due to high moisture control. Polyhydroxyalkanoates and polylactic acid (PLA) are renewable materials that have been recently introduced to the market, but their application in meat products is still limited. To be classified as an edible film, the mechanical properties and acceptable control over gas and moisture exchange need to be improved. PLA and cellulose-based films possess the advantage of protection against oxygen and water permeation; however, the addition of functional substances plays an important role in their effects on the foods. Furthermore, the use of packaging materials is increasing due to consumer demand for natural high-quality food packaging that serves functions such as extended shelf-life and contamination protection. To support the importance moving toward biodegradable packaging for meat, this review presented novel perspectives regarding ecological impacts, commercial status, and consumer perspectives. Those aspects are then evaluated with the specific consideration of regulations and perspective in the European Union (EU) for employing renewable and ecological meat packaging materials. This review also helps to highlight the situation regarding biodegradable food packaging for meat in the EU specifically.


Asunto(s)
Embalaje de Alimentos , Poliésteres , Unión Europea , Poliésteres/química , Carne , Celulosa , Plásticos
6.
Bioresour Technol ; 371: 128591, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36627085

RESUMEN

A new cutting-edge lignocellulose fractionation technology for the co-production of glucose, native-like lignin, and furfural was introduced using mannitol (MT)-assisted p-toluenesulfonic acid/pentanol pretreatment, as an eco-friendly process. The addition of optimized 5% MT in pretreatment enhanced the delignification rate by 29% and enlarged the surface area and biomass porosity by 1.07-1.80 folds. This increased the glucose yield by 45% (from 65.34 to 94.54%) after enzymatic hydrolysis relative to those without MT. The extracted lignin in the organic phase of pretreatment exhibited ß-O-4 bonds (61.54/100 Ar) properties of native cellulosic enzyme lignin. Lignin characterization and molecular docking analyses revealed that the hydroxyl tails of MT were incorporated with lignin and formed etherified lignin, which preserved high lignin integrity. The solubilized hemicellulose (96%) in the liquid phase of pretreatment was converted into furfural with a yield of 83.99%. The MT-assisted pretreatment could contribute to a waste-free biorefinery pathway toward a circular bioeconomy.


Asunto(s)
Glucosa , Lignina , Lignina/química , Glucosa/metabolismo , Furaldehído , Pentanoles , Manitol , Simulación del Acoplamiento Molecular , Hidrólisis , Biomasa
7.
Bioresour Technol ; 368: 128316, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36375700

RESUMEN

The organic fraction of municipal solid waste (OFMSW) is a widely-available promising feedstock for biofuel production. However, the presence of different inhibitors originating from fruit and food/beverage wastes as well as recalcitrant lignocellulosic fractions hampers its bioconversion. This necessitates a pretreatment to augment the biodigestibility and fermentability of OFMSW. Hence, this review aims to provide the in-vogue inhibitory compound removal and pretreatment techniques that have been employed for efficient OFMSW conversion into biofuels, i.e., hydrogen, biogas, ethanol, and butanol. The techniques are compared concerning their mode of action, chemical and energy consumption, inhibitor formation and removal, economic feasibility, and environmental sustainability. This critique also reviews the existing knowledge gap and future perspectives for efficient OFMSW valorization. The insights provided pave the way toward developing energy-resilient cities while addressing environmental crises related to generating OFMSW.


Asunto(s)
Eliminación de Residuos , Residuos Sólidos , Residuos Sólidos/análisis , Biocombustibles/análisis , Eliminación de Residuos/métodos , Anaerobiosis , Reactores Biológicos , Frutas/química , Metano
8.
Environ Res ; 215(Pt 1): 114291, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36103929

RESUMEN

Fermentable sugar production from lignocellulosic biomass has received considerable attention and has been dramatic progress recently. However, due to low enzymatic hydrolysis (EH) yields and rates, a high dosage of the costly enzyme is required, which is a bottleneck for commercial applications. Over the last decades, various strategies have been developed to reduce cellulase enzyme costs. The progress of the non-catalytic additive proteins in mitigating inhibition in EH is discussed in detail in this review. The low efficiency of EH is mostly due to soluble lignin compounds, insoluble lignin, and harsh thermal and mechanical conditions of the EH process. Adding non-catalytic proteins into the EH is considered a simple and efficient approach to boost hydrolysis yield. This review discussed the multiple mechanical steps involved in the EH process. The effect of physicochemical properties of modified lignin on EH and its interaction with cellulase and cellulose are identified and discussed, which include hydrogen bonding, hydrophobic, electrostatic, and cation-π interactions, as well as physical barriers. Moreover, the effects of different conditions of EH that lead to cellulase deactivation by thermal and mechanical mechanisms are also explained. Finally, recent advances in the development, potential mechanisms, and economic feasibility of non-catalytic proteins on EH are evaluated and perspectives are presented.


Asunto(s)
Celulasa , Lignina , Biomasa , Celulasa/química , Celulasa/metabolismo , Celulosa/química , Celulosa/metabolismo , Hidrólisis , Lignina/química , Estudios Prospectivos , Azúcares
9.
Bioresour Technol ; 361: 127701, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35905873

RESUMEN

The current study investigated the effect of elevating gas pressure on biomethanation in trickle-bed reactors (TBRs). The increased pressure led to successful biomethanation (CH4 > 90 %) at a gas retention time (GRT) of 21 min, due to the improved transfer rates of H2 and CO2. On the contrary, the non-pressurized TBR performance was reduced at GRTs shorter than 40 min. Metagenomic analysis revealed that the microbial populations collected from the lower and middle parts of the reactor under the same GRT were more homogeneous compared with those developed in the upper layer. Comparison with previous experiments suggest that microbial stratification is mainly driven by the nutrient provision strategy. Methanobacterium species was the most dominant methanogen and it was mainly associated with the bottom and middle parts of TBRs. Overall, the increased pressure did not affect markedly the microbial composition, while the GRT was the most important parameter shaping the microbiomes.


Asunto(s)
Euryarchaeota , Microbiota , Biocombustibles , Reactores Biológicos , Hidrógeno , Metano , Microbiota/genética
10.
Bioresour Technol ; 360: 127609, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35840021

RESUMEN

Potato is the fourth most abundant crop harvested annually worldwide. Potato peel waste (PPW) is the main waste stream of potato-processing industries which is generated in large quantities and is a threat to the environment globally. However, owing to its compositional characteristics, availability, and zero cost, PPW is a renewable resource for the production of high-value bioproducts. Hence, this study provides a state-of-the-art overview of advancements in PPW valorization through biological and thermochemical conversions. PPW has a high potential for biofuel and biochemical generation through detoxification, pretreatment, hydrolysis, and fermentation. Moreover, many other valuable chemicals, including bio-oil, biochar, and biosorbents, can be produced via thermochemical conversions. However, several challenges are associated with the biological and thermochemical processing of PPW. The insights provided in this review pave the way toward a PPW-based biorefinery development, providing sustainable alternatives to fossil-based products and mitigating environmental concerns.


Asunto(s)
Biocombustibles , Solanum tuberosum , Fermentación , Hidrólisis
11.
Bioresour Technol ; 359: 127503, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35728765

RESUMEN

To valorize whole lignocellulosic biomass, this study proposed a biphasic solvent system using dilute acid (DA)/pentanol pretreatment. Effects of the key factors, i.e., temperature and pentanol concentration, on aspen were evaluated. Under identified optimal pretreatment conditions (160 °C, 60% pentanol), 85% and 91% of lignin and hemicellulose were solubilized in separate organic and liquid phases, respectively, while 91.1% of cellulose was retained in solid fraction. Enzymatic digestibility efficiency of pretreated cellulose was âˆ¼ 6.4-times higher than that of untreated biomass. Notably, excellent pentanol recovery rates were obtained after four-times recycling (84%) with great cellulose digestibility (81%) and delignification (71%) performance. The recovered lignin contained low levels of contaminated sugars (<1%), while it could stabilize and protect high amounts of ß-O-4 bonds. Besides, high phenolic OH content was found in lignin, which could be utilized for lignin-based biomaterials. Therefore, DA/pentanol pretreatment is an innovative promising technology for lignocellulosic valorization towards biorefinery.


Asunto(s)
Lignina , Azúcares , Ácidos , Biomasa , Carbohidratos , Celulosa , Hidrólisis , Lignina/química , Pentanoles
12.
J Environ Manage ; 303: 114138, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34838385

RESUMEN

Vinasse and whey are wastewaters that are produced in large quantities in the sugar-to-ethanol and dairy industries, respectively. They pose a considerable threat to the environment due to the high concentration of nutrients and COD. In this study, the potential of producing protein-rich fungal biomass and biomethane from vinasse and whey through a two-stage biorefinery was examined. In the first stage, an edible and safe for human filamentous fungus, Neurospora intermedia, was cultivated on these wastewaters. To maximize the fungal biomass yield, the cultivation parameters, i.e., pH, vinasse to whey ratio, incubation time, and nutrients supplementation, were optimized. The highest yield of 12.0 g biomass per L of wastewaters was obtained by cultivation at pH 6.5 and vinasse to whey ratio of 25:75 (v/v) for 96 h with nitrogen source supplementation. The N. intermedia biomass contained about 45% protein and noticeable essential amino acid contents, comparable to commercial sources of protein for aquatic feed such as soybean meal and fishmeal. In the second stage, the effluent of fungal cultivation was anaerobically digested to produce 425 mL/g VS biomethane. Overall, 1 m3 of wastewater yielded 5.4 kg crude protein and 10.3 m3 methane, accompanied by 93.3% COD removal.


Asunto(s)
Biocombustibles , Suero Lácteo , Biomasa , Reactores Biológicos , Humanos , Metano
13.
Sci Total Environ ; 802: 149842, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34455274

RESUMEN

Global environmental awareness has encouraged further research towards biofuel production and consumption. Despite the favorable properties of biofuels, the sustainability of their conventional production pathways from agricultural feedstocks has been questioned. Therefore, the use of non-food feedstocks as a promising approach to ensure sustainable biofuel production is encouraged. However, the use of synthetic solvents/chemicals and energy carriers during biofuel production and the consequent adverse environmental effects are still challenging. On the other hand, biofuel production is also associated with generating large volumes of waste and wastewater. Accordingly, the circular bioeconomy as an innovative approach to ensure complete valorization of feedstocks and generated waste streams under the biorefinery scheme is proposed. In line with that, the current study aims to assess the environmental sustainability of bioethanol production in a safflower-based biorefinery using the life cycle assessment framework. Based on the obtained results, safflower production and its processing into 1 MJ bioethanol under the safflower-based biorefinery led to damage of 2.23E-07 disability-adjusted life years (DALY), 2.35E-02 potentially disappeared fraction (PDF)*m2*yr, 4.76E-01 kg CO2 eq., and 3.82 MJ primary on the human health, ecosystem quality, climate change, and resources, respectively. Moreover, it was revealed that despite adverse environmental effects associated with safflower production and processing, the substitution of conventional products, i.e., products that are the typical products in the market without having environmental criteria, with their bio-counterparts, i.e., products produced in the biorefinery based on environmental criteria could overshadow the unfavorable effects and substantially enhance the overall sustainability of the biorefinery system. The developed safflower-based biorefinery led to seven- and two-time reduction in damage to the ecosystem quality and resources damage categories, respectively. The reductions in damage to human health and climate change were also found to be 52% and 24%, respectively. The weighted environmental impacts of the safflower-based biorefinery decreased by 64% due to the production of bioproducts, mainly biodiesel and biogas, replacing their fossil-based counterparts, i.e., diesel and natural gas, respectively. Finally, although the main focus of the developed safflower-based biorefinery was biofuel production, waste valorization and mainly animal feed played a significant role in improving the associated environmental impacts.


Asunto(s)
Biocombustibles , Carthamus tinctorius , Animales , Biomasa , Ecosistema , Humanos , Estadios del Ciclo de Vida
14.
Chemosphere ; 291(Pt 1): 133003, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34808197

RESUMEN

Potato processing industries generate considerable amounts of residues, i.e., potato peel wastes (PPW). Valorization of PPW for bioethanol and biogas production via a biorefining process was investigated in this study. Organosolv pretreatment was performed on the PPW using 50-75% (v/v) ethanol solution at 120-180 °C with/without the presence of 1% (w/w) H2SO4 (as a catalyst). After the pretreatment, the solvent, i.e., ethanol, was recovered by distillation. Catalyzed organosolv pretreatment using 50% (v/v) ethanol at 120 °C followed by enzymatic hydrolysis resulted in a high hydrolysate yield of 539.8 g glucose/kg dry PPW that was successfully fermented to 224.2 g ethanol/kg dry PPW. To recover more energy, the liquid fraction of the pretreatment remained after solvent recovery and the unhydrolyzed solids that remained from the enzymatic hydrolysis were anaerobically digested. From each kg of dry PPW, the anaerobic digestion produced 57.9 L biomethane. Thus, the biorefinery comprising ethanolic organosolv pretreatment, solvent recovery, enzymatic hydrolysis, ethanolic fermentation, and anaerobic digestion of residues was produced 8112 kJ energy per kg of dry PPW.


Asunto(s)
Biocombustibles , Solanum tuberosum , Etanol , Fermentación , Hidrólisis
15.
Bioresour Technol ; 341: 125834, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34479139

RESUMEN

Orange waste (OW), an abundant and severe globally environmental treat, was used for biobutanol and biohydrogen production emploing acetone-butanol-ethanol (ABE) fermentation through a biorefinery process. The solvent yield from untreated OW was insufficient; thus, the substrate was subjected to hydrothermal pretreatment before hydrolysis. The pretreatment at 140 ℃ for 30 min resulted in the solid with the highest yield of hydrolysis and fermentation. Moreover, the anaerobic digestion of hydrolysis residue produced appreciable amounts of biomethane. However, the pretreatment liquor was not fermentable; thus, it was detoxified by overliming for 24 h at 30 ℃ and then fermented. Overall, this sustainable biorefinery, based on pretreatment without any additional chemical agent, hydrolysis of pretreated solids, detoxification of pretreatment liquor, ABE fermentation, and anaerobic digestion of residues, produced 42.3 g biobutanol, 33.1 g acetone, 13.4 g ethanol, 104.5 L biohydrogen, and 28.3 L biomethane per kg of OW that contained 4560 kJ energy.


Asunto(s)
Biocombustibles , Citrus sinensis , Acetona , Butanoles , Fermentación , Hidrólisis
16.
Bioresour Technol ; 337: 125356, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34102516

RESUMEN

Baker's yeast production industry generates large quantities of high chemical oxygen demand (COD) wastewater. The integration of baker's yeast wastewater (BYW) for an innovative two-step waste biorefinery process by producing protein-rich fungal biomass and biogas along with COD and nutrients removal was the main object of the present research. In the first step, fungal biomass production from BYW was investigated using four species of filamentous fungi. The maximum biomass yield of 5.13 g/L BYW containing 43.8% mycoprotein and 36.3% COD removal was achieved by A. oryzae. In the second step, to produce biogas and further remove organic matter, the effluent of fungal fermentation was subjected to anaerobic digestion and COD removal between 22.4 and 44.2% was obtained. Overall, 1 m3 of BYW yielded 5.13 kg of protein-rich biomass and 1.42 m3 of methane. Additionally, pigment production using N. intermedia was investigated, and 1.54 mg carotenoids/g biomass was produced.


Asunto(s)
Biocombustibles , Aguas Residuales , Anaerobiosis , Biomasa , Reactores Biológicos , Metano , Saccharomyces cerevisiae , Eliminación de Residuos Líquidos
17.
J Environ Manage ; 279: 111822, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33348185

RESUMEN

The huge amount of agro-wastes generated due to expanding agricultural activities can potentially cause serious environmental and human health problems. Using the biorefinery concept, all parts of agricultural plants can be converted into multiple value-added bioproducts while reducing waste generation. This approach can be viewed as an effective strategy in developing and realizing a circular bioeconomy by accomplishing the dual goals of waste mitigation and energy recovery. However, the sustainability issue of biorefineries should still be thoroughly scrutinized using comprehensive resource accounting methods such as exergy-based approaches. In light of that, this study aims to conduct a detailed exergy analysis of whole-crop safflower biorefinery consisting of six units, i.e., straw handling, biomass pretreatment, bioethanol production, wastewater treatment, oil extraction, and biodiesel production. The analysis is carried out to find the major exergy sink in the developed biorefinery and discover the bottlenecks for further performance improvements. Overall, the wastewater treatment unit exhibits to be the major exergy sink, amounting to over 70% of the total thermodynamic irreversibility of the process. The biomass pretreatment and bioethanol production units account for 12.4 and 10.3% of the total thermodynamic inefficiencies of the process, respectively. The exergy rates associated with bioethanol, biodiesel, lignin, biogas, liquid digestate, seed cake, sodium sulfate, and glycerol are determined to be 5918.5, 16516.8, 10778.9, 1741.4, 6271.5, 15755.8, 3.4, and 823.5 kW, respectively. The overall exergetic efficiency of the system stands at 72.7%, demonstrating the adequacy of the developed biorefinery from the thermodynamic perspective.


Asunto(s)
Carthamus tinctorius , Agricultura , Biocombustibles , Biomasa , Humanos , Lignina
18.
Bioresour Technol ; 319: 124167, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33017776

RESUMEN

Extractives are nonstructural constituents of lignocellulosic materials available in small portions; however, their influence on the bioconversion processes cannot be disregarded. This study evaluated the effect of various concentrations of rice straw water extractives (RWE) and ethanol extractives (REE) on enzymatic hydrolysis, anaerobic digestion, and simultaneous saccharification and fermentation productivity. By increasing the RWE or REE concentration, the glucose yield did not change after 72 h of enzymatic hydrolysis. The RWE increment enhanced ethanol yield to 95.6%. However, the REE increment decreased ethanol yield to 32.1%. Adding RWE caused a considerable reduction in the accumulated biogas and changed the composition of produced biogas from 74% methane to less than 1%. By increasing the REE concentration, the accumulated biogas increased from 167.9 to 524.4 ml/g VS. According to the gas chromatography-mass spectrometry (GC/MS) results, the most abundant RWE and REE components were 3-hydroxy-Spirost-8-en-11-one and guaiazulene, respectively.


Asunto(s)
Biocombustibles , Oryza , Etanol , Fermentación , Hidrólisis
19.
Waste Manag ; 118: 45-54, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32889233

RESUMEN

Co-processing of lignocellulosic wastes, e.g., garden and paper wastes, and the organic matters fraction of municipal solid waste (OMSW) in an integrated bioprocess is a possible approach to realize the potential of wastes for biobutanol production. Dilute acid pretreatment is a multi-functional stage for breaking the recalcitrant lignocellulose's structure, hydrolyzing hemicellulose, and hydrolyzing/solubilizing starch, leading to a pretreated solid and a rich hydrolysate. In this study, dilute-acid pretreatment of the combination of wastepaper and OMSW, composite I, as well as garden waste and OMSW, composite II, at severe conditions resulted in "pretreatment hydrolysates" containing 33.7 and 19.4 g/L sugar along with 18.9 and 33.2 g/L soluble starch, respectively. In addition, the hydrolysis of solid remained after the pretreatment of composite I and II resulted in "enzymatic hydrolysates" comprising 19.4 and 33 g/L sugar, respectively. The fermentation of the pretreatment hydrolysates and enzymatic hydrolysates resulted in 3.5 and 6.4 g/L ABE from composite I and 15 and 5.2 g/L ABE from composite II, respectively. In this process, 148 and 173 g ABE (60 and 100 g gasoline equivalent/kg) was obtained from each kg composite I and composite II, respectively, where co-processing of OMSW with lignocellulosic wastes resulted in 10 and 49% higher ABE than that produced from the individual substrates.


Asunto(s)
Butanoles , Residuos Sólidos , Fermentación , Hidrólisis , Lignina/metabolismo
20.
Waste Manag ; 116: 40-48, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32784120

RESUMEN

Municipal solid waste is an environmental threat worldwide; however, the organic fraction of municipal solid waste (OF-MSW) has a great potential for the generation of fuels and high-value products. In the current study, OF-MSW was utilized for the production of ethanol, hydrogen, as well as 2,3-butanediol, an octane booster, by using Enterobacter aerogenes. Furthermore, a promising alternative to non-biodegradable petrochemical-based polymers, polyhydroxyalkanoates (PHAs), was produced. The OF-MSW was first pretreated by an acetic acid catalyzed ethanol organosolv pretreatment at 120 and 160 °C followed by enzymatic hydrolysis of the residual solids. The residual unhydrolyzed solids resulting from enzymatic hydrolysis were further anaerobically digested for methane production. The enzymatic hydrolysis of the solids prepared at 120 °C for 60 min led to the production of hydrolysate with the highest glucose production yield of 498.5 g/kg dry untreated OF-MSW, which was fermented to 139.1 g 2,3-butanediol, 98.3 g ethanol, 28.6 g acetic acid, 71.4 L biohydrogen, and 40 g PHAs. Moreover, 23.1 L biomethane was produced through the anaerobic digestion of the enzymatic hydrolysis residue solids. Thus, appreciable amounts of energy (8236.9 kJ) and an eco-friendly bioplastic were produced by the valorization of carbon sources available in OF-MSW.


Asunto(s)
Biocombustibles , Residuos Sólidos , Anaerobiosis , Etanol , Hidrógeno , Hidrólisis , Metano
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