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1.
Waste Manag ; 118: 626-636, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33011540

RESUMO

Due to its environment-friendly and replenishable characteristics, biodiesel has the potential to substitute fossil fuels as an alternative source of energy. Although biodiesel has many benefits to offer, manufacturing biodiesel on an industrial scale is uneconomical as a high cost of feedstock is required. A novel sulfonated and magnetic catalyst synthesised from a palm kernel shell (PMB-SO3H) was first introduced in this study for methyl ester or biodiesel production to reduce capital costs. The wasted palm kernel shell (PKS) biochar impregnated with ferrite Fe3O4 was synthesised with concentrated sulphuric acid through the sulfonation process. The SEM, EDX, FTIR, VSM and TGA characterization of the catalysts were presented. Then, the optimisation of biodiesel synthesis was catalysed by PMB-SO3H via the Response Surface Methodology (RSM). It was found that the maximum biodiesel yield of 90.2% was achieved under these optimum operating conditions: 65 °C, 102 min, methanol to oil ratio of 13:1 and the catalyst loading of 3.66 wt%. Overall, PMB-SO3H demonstrated acceptable catalysing capability on its first cycle, which subsequently showed a reduction of the reusability performance after 4 cycles. An important practical implication is that PMB-SO3H can be established as a promising heterogeneous catalyst by incorporating an iron layer which can substantially improve the catalyst separation performance in biodiesel production.


Assuntos
Biocombustíveis , Óleos Vegetais , Carvão Vegetal , Esterificação , Fenômenos Magnéticos
2.
Waste Manag ; 118: 667-676, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33011544

RESUMO

This paper compares the yield and composition of bio-oil derived through stepwise and continuous pyrolysis of agro-residues. The temperature steps were selected using thermogravimetric analysis. Groundnut shell, empty fruit bunch pellets, and rice straw were pyrolyzed at 305 °C in the first step and 600 °C in the second step and pinewood chips were pyrolyzed at 340 °C and 600 °C. The cumulated yields of bio-oil were lower in both continuous and stepwise pyrolysis for agro-residues in comparison with woody biomass, with a corresponding increase in biochar and pyrolysis gas yields. Approximately 50% of the pinewood and 31-40% of the agro-residues were converted to bio-oil through both methods. This trend is explained by the differing biochemical composition of biomasses, and concentrations of inorganic components. Bio-oil fractions were separated into water-soluble and water-insoluble compounds before characterization. Bio-oil obtained in the first step was richer in organic acids, anhydrosugars, and carbonyl compounds, while the later fraction of bio-oil was richer in unbranched phenolic compounds. Thus, compounds known to promote bio-oil aging were separated into different fractions. Further, stepwise pyrolysis proved to be most effective for groundnut shells in isolating chemicals with a minimum loss of yield compared to continuous pyrolysis. A preliminary economic assessment of bio-oil showed that the value of bio-oil for crop residues was improved by 2-2.5 times during stepwise heating while for pinewood it reduced by half. This study provides a good starting point for further research in optimizing the temperature steps for pyrolysis and separation of chemicals from bio-oil.


Assuntos
Biocombustíveis , Pirólise , Biocombustíveis/análise , Biomassa , Fenóis , Madeira/química
3.
Nat Commun ; 11(1): 4879, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978379

RESUMO

Synthetic biology allows us to bioengineer cells to synthesize novel valuable molecules such as renewable biofuels or anticancer drugs. However, traditional synthetic biology approaches involve ad-hoc engineering practices, which lead to long development times. Here, we present the Automated Recommendation Tool (ART), a tool that leverages machine learning and probabilistic modeling techniques to guide synthetic biology in a systematic fashion, without the need for a full mechanistic understanding of the biological system. Using sampling-based optimization, ART provides a set of recommended strains to be built in the next engineering cycle, alongside probabilistic predictions of their production levels. We demonstrate the capabilities of ART on simulated data sets, as well as experimental data from real metabolic engineering projects producing renewable biofuels, hoppy flavored beer without hops, fatty acids, and tryptophan. Finally, we discuss the limitations of this approach, and the practical consequences of the underlying assumptions failing.


Assuntos
Aprendizado de Máquina , Engenharia Metabólica/métodos , Biologia Sintética/métodos , Teorema de Bayes , Cerveja , Biocombustíveis , Dodecanol/metabolismo , Escherichia coli/metabolismo , Ácidos Graxos/metabolismo , Saccharomyces cerevisiae/metabolismo
4.
Bioresour Technol ; 317: 124026, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32866839

RESUMO

In this study, a combined approach to produce fatty acid methyl esters (FAMEs) and succinic acid from the biomass of the microalga Micractinium sp. IC-44 using ionic liquids (ILs) was presented. After 22 days of cultivation, the biomass productivity was 0.034 ± 0.001 g L-1day-1, and the lipid content was 11.5 ± 0.5%. Direct biomass transesterification using H2SO4 in the presence of IL [BMIM][HSO4] resulted in a FAME yield of 42.0 ± 4.3%, which exceeded the yields obtained after transesterification of extracted lipids (20.5 ± 3.5% using ILs and 27.1 ± 2.4% using methanol/chloroform) and direct biomass transesterification without using ILs (31.6 ± 1.7%). The residual biomass obtained after direct transesterification using ILs was subjected to acid hydrolysis (sugar yield was 81.1 ± 2.4%). The purified hydrolysate was fermented using Actinobacillus succinogenes 130Z to obtain a succinic acid yield of 0.67 g g-1 of fermentable sugars. Therefore, this study demonstrated the successful conversion of the Micractinium sp. IC-44 biomass into biodiesel and succinic acid.


Assuntos
Biocombustíveis , Microalgas , Actinobacillus , Biomassa , Ácido Succínico
5.
Water Sci Technol ; 82(3): 549-564, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32960799

RESUMO

Sludge from textile effluent treatment plants (ETP) remains a challenge for many industries due to inefficient and limited waste management strategies. This study explores the potential of using anaerobic digestion (AD) to improve the environmental quality of textile ETP sludge. The AD of ETP sludge is affected by the low C/N ratio (3.7), heavy metal content, and toxicity. To improve the process, co-digestion of ETP sludge with different substrates (sewage sludge, cow dung, and sawdust) under mesophilic conditions (37 °C), followed by a thermochemical pretreatment was assessed. The results showed that anaerobic co-digestion of the textile sludge with the co-substrates is effective in reducing pollution load. It was found that organic matters degraded during the 30-day AD process. The chemical oxygen demand and biological oxygen demand reduction was in the range of 33.1-88.5% and 48.1-67.1%, respectively. Also, heavy metal (cadmium, lead, iron, and, mercury) concentration was slightly reduced after digestion. Maximal biogas yield was achieved from co-digestion of textile sludge and sewage sludge at a mixing ratio of 3:1, 1:1, and 1:3, and methane content was respectively 87.9%, 68.9%, and 69.5% of the gas composition. The results from this study show that co-digestion will not only reduce the environmental pollution and health risks from the textile industry but also recover useful energy.


Assuntos
Esgotos , Águas Residuárias , Anaerobiose , Animais , Biocombustíveis , Reatores Biológicos , Bovinos , Feminino , Metano , Têxteis
6.
Vet Clin North Am Food Anim Pract ; 36(3): 653-659, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32948412

RESUMO

Corn co-products are a co-product of the dry and wet corn-milling ethanol manufacturing industry. The dry mill corn co-product is distiller's grains. Distillers grain can be further categorized into dry distillers grains (DDG), DDG with solubles, wet distillers grains with solubles (WDGS), modified WDGS, and corn syrup (solubles). Wet mill ethanol production produces 2 main feed stuffs: corn gluten (wet and dry) and heavy steep water.


Assuntos
Biocombustíveis/envenenamento , Doenças dos Bovinos/induzido quimicamente , Encefalomalacia/veterinária , Ração Animal/análise , Animais , Bovinos , Doenças dos Bovinos/metabolismo , Dieta/veterinária , Encefalomalacia/induzido quimicamente , Encefalomalacia/metabolismo , Sulfeto de Hidrogênio/metabolismo , Ruminantes , Zea mays/química
7.
Waste Manag ; 118: 79-89, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32891026

RESUMO

The management of food waste has been considered an extremely important issue since the 1990s but finding efficient solutions for small and rural communities is still challenging. Anaerobic digestion (AD) may provide interesting opportunities in terms of carbon emissions and economic payback in the long term, but the choice of the correct technology and the spatial scale requires attention. The focus of this study is on a small rural municipality, which is selected as a case study to assess the environmental and economic sustainability of the application of two options for AD (a conventional and an alternative wet process) and two spatial scales (municipality and a consortium of municipalities). Both the AD configurations are examined in terms of biogas exploitation, through a combined heat and power generator, and in combination with a post-composting stage of the digestate. From economic and environmental perspectives, the consortium-scale application of the conventional wet process is expected to generate greater benefits in the long term, as it enables 80% more electric energy production and economic revenues/savings, and avoids carbon emissions. However, before selecting the technology, decision makers should consider the public acceptance of local communities (e.g., the susceptibility to the "not-in-my-backyard" syndrome), as the best technical-economical solution may not be the most appropriate to specific communities. The methodology developed in this paper and the discussion of the results will inform decision makers about how to identify the most appropriate alternative for their purposes.


Assuntos
Eliminação de Resíduos , Anaerobiose , Biocombustíveis , Cidades , Alimentos , Humanos , População Rural
8.
Waste Manag ; 118: 99-109, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32892099

RESUMO

The performance of a small-scale prototype digestion plant (7.2 m3 working volume) intended for decentralised operation was evaluated considering energy efficiency and technical suitability for biogas valorisation in producing electrical and thermal energy. The digester operated in recirculation mode to enhance organic matter conversion and improve volatile solid degradation. An energy assessment of the process assumed the incorporation of a combined heat and power (CHP) unit. The coefficient of overall performance of the plant for electrical energy (COPel) was 0.95 - this values was estimated at an electrical efficiency of 22.5% and represents the ratio between energy production and consumption - for a methane yield of 360 L/kg VS and an organic loading rate (OLR) of 1.06 g VS/L d. This parameter was slightly lower than the unit thus indicating that the micro-plant was close to attaining self-sufficiency regarding electrical energy use. The temperature increase of the feed to process conditions supposed a significant amount of thermal energy which highly compromised the efficiency when operating at low organic load, thus accounting for more than 80% of the total energy demand of the installation. When the energy assessment of the process was performed at higher OLR of 2.7 g VS/ L d, the resulting COPel value was1.68, demonstrating the feasibility of this configuration for decentralised digestion.


Assuntos
Reatores Biológicos , Metano , Anaerobiose , Biocombustíveis
9.
Waste Manag ; 118: 521-533, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32980731

RESUMO

In this study, Co-HTC of food waste with yard waste was conducted for biofuel pellets production, and also to understand any possible synergy between two feedstock types. The calorific value of blended raw feedstock was 13.5 MJ/kg which increased to 27.6 MJ/kg after Co-HTC at 220 °C for 1 h. Energy yield and fuel ratio calculated was 45% and 0.65 respectively. Hydrochar produced demonstrated a stable combustion profile as compared to reactive combustion profile for raw samples. The blend of food and yard waste hydrochar was easily pelletized, and its pellets showed improvement in mechanical properties as compared to pellets made from mono-substrate((food waste) hydrochar. Pellets produced from the blend of food and yard waste hydrochar showed higher energy (46.4 MJ/m3) and mass density (1679 kg/m3) as compare to the pellet produced from food waste hydrochar alone. Tensile strength obtained for the blended hydrochar pellet was 2.64 MPa while same for the pellets produced from food waste hydrochar alone was 1.30 MPa. In addition to improving hydrophobicity, soften lignin from yard waste also helped in binding the food waste hydrochar particles together within the pellets matrix during heated pelletization. The results presented in the study indicated that in the presence of all favorable conditions, there is a potential that approximately 11% of the global coal consumption could be replaced by the combustion of hydrochar produced from food and yard waste globally.


Assuntos
Biocombustíveis , Eliminação de Resíduos , Carbono , Alimentos , Temperatura
11.
Water Sci Technol ; 82(1): 144-156, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32910799

RESUMO

To accelerate the degradation of substrate, 50% liquid digestate recirculation (LDR) was used in the anaerobic digestion (AD) of corn straw. The effects of recirculation on the enzyme activities and biogas production were investigated by comparing with control reactor (ReactorCK). During the AD process, the fermentation system with 50% LDR was more stable. The average biogas and methane production in ReactorLDR were 7,891 mL·d-1 and 347 mL CH4·g-1 VSadded·d-1 respectively. The total volatile fatty acids (TVFAs) concentration in the two reactors both increased at first and then decreased with time. The LDR made the VFAs accumulation significant, especially propionic acid accumulation in 4 ∼ 16 days. The maximum peak value of cellulase, xylanase, dehydrogenase and coenzyme F420 activities in ReactorLDR were 0.51 mg·g-1·h-1, 0.29 mg·g-1·h-1, 4.88 mL·g-1·h-1 and 6.69 µmol·L-1, respectively, which were higher than that in ReactorCK. With or without recirculation, the concentration of TVFAs was positively correlated with cellulase, xylanase and dehydrogenase activities, while was negatively correlated with coenzyme F420 activity. Besides, a very significant correlation existed between hydrolase and dehydrogenase activities and daily biogas production in ReactorCK. And the peaks of cellulase, xylanase and dehydrogenase activities appeared ahead of the peak of daily biogas production with the LDR.


Assuntos
Biocombustíveis , Zea mays , Anaerobiose , Ácidos Graxos Voláteis , Fermentação
12.
Bioresour Technol ; 317: 124031, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32871332

RESUMO

The hydrothermal liquefaction (HTL) of As enriched Pteris vittata L. (PVL, hyper-accumulator biomass) was performed with the recycled aqueous phase as reaction medium, aiming to dispose the biomass with high water content and produce high-quality bio-oil. After three times of aqueous phase recycling at 275 °C, 30 min, the bio-oil yield increased to 30.32% from 21.54% and the higher heating value (HHV, 28.51 MJ/kg) of the bio-oil was higher than that of the bio-oil from HTL with pure water (26.80 MJ/kg). The main compounds detected in bio-oils were phenols, ketones, hydrocarbons, and aldehydes. Acetic acid (17.21-24.77 mg/mL) was dominant in the aqueous phases, resulting in the low pH (4.31-4.89). The heavy metals (Cu, Pb, Zn, Cd) mainly remained in bio-char whereas As was transferred to aqueous phase. Thus, HTL by aqueous phase recycling could be a promising way for PVL treatment to obtain high-quality bio-oil and arsenic recovery.


Assuntos
Metais Pesados , Pteris , Biocombustíveis , Biomassa , Óleos Vegetais , Polifenóis , Temperatura , Água
13.
Bioresour Technol ; 317: 124042, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32889177

RESUMO

The present study was to assess the economic benefit of integrated P. tuoliensis cultivation and biogas production based on the utilization of lignocellulosic biomass. Among the five evaluated cultivation substrates, that consisting of 55% cottonseed hull, 25% corncob, 10% wheat bran, 5% corn flour, 4% lime, and 1% gypsum was demonstrated to be optimal for the simultaneous production of P. tuoliensis mushrooms and biogas fuel. Preliminary estimation shows that, for the consumption of dry substrate per unit mass (calculated in per kg), a total of 561 g fresh mushroom product was harvested and 189.88 L biogas was generated. Accordingly, the production costs were abolished and an economic benefit of approximately $0.592 was obtained, with the high-value mushroom product being the main contributor to profit. Moreover, this integrated process also exhibited positive ecological and social benefits and as such, is worthy of promotion and further application.


Assuntos
Biocombustíveis , Pleurotus , Biomassa , Lignina
14.
Physiol Plant ; 170(1): 7-9, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32830334

RESUMO

Cyanobacteria require light to perform photosynthesis, but not all colors of light are equally useable for them. In particular, blue light-grown cyanobacterial strains, including the well-studied model organism Synechocystis sp. PCC 6803 (Synechocystis), have been observed to exhibit slower growth rates than white or red light-grown cells. In this issue of Physiologia Plantarum, Luimstra et al. (2020) have attempted to understand why cyanobacterial cells suffer under blue light. They measured the molecular and genetic responses of Synechocystis cells to being shifted from white light to blue light. They found that blue light-grown cells make changes that lead to a redistribution of energy flow between the two photosystems that power photosynthesis. These findings could help researchers identify avenues for optimizing photosynthesis in cyanobacterial species, a group of organisms which show great promise as potential solar-powered factories for the production of biofuels and other high-value products.


Assuntos
Synechocystis , Biocombustíveis , Cor , Fotossíntese/genética
15.
J Environ Manage ; 275: 111233, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32827897

RESUMO

Increasing marine land-based recirculating aquaculture systems (RAS) and stricter environmental regulations, pose new challenges to the aquaculture industry on how to treat and dispose saline fish wastewater. The fish wastewater could be incorporated into biogas reactors, but currently, the effects of salinity on the biomethanation process are poorly known. This study aimed to assess the toxicity of fish wastewater with different salinities on the biomethanation process and to propose optimum co-digestion scenarios for maximal methane potential and safe use in biogas plants. Results showed that, depending on salinity and organic content, it is possible to efficiently co-digest from 3.22 to 61.85% fish wastewater (v/v, wastewater/manure) and improve the maximum methane production rate from 2.72 to 61.85%, respectively compared to cow manure mono-digestion. Additionally, salinity was identified as the main inhibitor of biomethanation process with a half-maximal inhibitory concentration (IC50) of 4.37 g L-1, while sulphate reduction was identified as a secondary inhibitor.


Assuntos
Biocombustíveis , Peixes , Águas Residuárias , Anaerobiose , Animais , Biocombustíveis/toxicidade , Reatores Biológicos , Bovinos , Feminino , Esterco , Metano
16.
Bioresour Technol ; 317: 123994, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32836034

RESUMO

The effects of long-term acclimatization on the optimum food waste to cow manure ratio (FW/CM) and substrate to inoculum ratio (S/I) in anaerobic codigestion with FW and CM were investigated by batch trials. For the unacclimated sludge, the highest CH4 yields of 646.6 and 653.4 mL/g VS were achieved under the optimum FW/CM (2.5 VS/VS) and S/I (0.07 VS/VS) ratios, respectively. After more than 550 days of acclimatization, the optimum FW/CM and S/I of the acclimated sludge were improved to 3.4 and 0.68 VS/VS with more anaerobic digestion enzymes and lignocellulose, respectively. Based on high-throughput sequencing analysis, the microbial community structures of bacteria, fungi, and archaea were changed, which was the main reason for the change in the optimum FW/CM and S/I. Therefore, the FW/CM and S/I should be periodically optimized during the long-term operation of codigestion to improve the codigestion efficiency for biogas production.


Assuntos
Esterco , Eliminação de Resíduos , Aclimatação , Anaerobiose , Animais , Biocombustíveis , Reatores Biológicos , Bovinos , Feminino , Alimentos , Metano
17.
Plant Mol Biol ; 104(3): 283-296, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32740897

RESUMO

KEY MESSAGE: Differences in FAE1 enzyme affinity for the acyl-CoA substrates, as well as the balance between the different pathways involved in their incorporation to triacylglycerol might be determinant of the different composition of the seed oil in Brassicaceae. Brassicaceae present a great heterogeneity of seed oil and fatty acid composition, accumulating Very Long Chain Fatty Acids with industrial applications. However, the molecular determinants of these differences remain elusive. We have studied the ß-ketoacyl-CoA synthase from the high erucic feedstock Thlaspi arvense (Pennycress). Functional characterization of the Pennycress FAE1 enzyme was performed in two Arabidopsis backgrounds; Col-0, with less than 2.5% of erucic acid in its seed oil and the fae1-1 mutant, deficient in FAE1 activity, that did not accumulate erucic acid. Seed-specific expression of the Pennycress FAE1 gene in Col-0 resulted in a 3 to fourfold increase of erucic acid content in the seed oil. This increase was concomitant with a decrease of eicosenoic acid levels without changes in oleic ones. Interestingly, only small changes in eicosenoic and erucic acid levels occurred when the Pennycress FAE1 gene was expressed in the fae1-1 mutant, with high levels of oleic acid available for elongation, suggesting that the Pennycress FAE1 enzyme showed higher affinity for eicosenoic acid substrates, than for oleic ones in Arabidopsis. Erucic acid was incorporated to triacylglycerol in the transgenic lines without significant changes in their levels in the diacylglycerol fraction, suggesting that erucic acid was preferentially incorporated to triacylglycerol via DGAT1. Expression analysis of FAE1, AtDGAT1, AtLPCAT1 and AtPDAT1 genes in the transgenic lines further supported this conclusion. Differences in FAE1 affinity for the oleic and eicosenoic substrates among Brassicaceae, as well as their incorporation to triacylglycerol might explain the differences in composition of their seed oil.


Assuntos
3-Oxoacil-(Proteína de Transporte de Acila) Sintase/metabolismo , Biocombustíveis , Vias Biossintéticas , Brassicaceae/metabolismo , Thlaspi/enzimologia , Thlaspi/metabolismo , Triglicerídeos/biossíntese , 1-Acilglicerofosfocolina O-Aciltransferase/metabolismo , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/genética , Aciltransferases/metabolismo , Sequência de Aminoácidos , Proteínas de Arabidopsis/metabolismo , Vias Biossintéticas/genética , Diacilglicerol O-Aciltransferase/metabolismo , Ácidos Erúcicos/metabolismo , Elongases de Ácidos Graxos/genética , Elongases de Ácidos Graxos/metabolismo , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica de Plantas , Fenótipo , Óleos Vegetais/metabolismo , Plantas Geneticamente Modificadas , Sementes/genética , Análise de Sequência , Thlaspi/genética , Transcriptoma
18.
J Environ Manage ; 271: 111041, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32778320

RESUMO

Lipid production in microalgae under nitrogen (N) starved condition can be enhanced by excess phosphorus (P) supply in the second stage of two-stage cultivation strategy. However, implementing two-stage cultivation is difficult in large-scale cultivation system as it requires high energy of transferring large algal biomass from first stage to second stage. To address this problem, we have optimized a continuous two-stage (CTS) cultivation strategy using Chlorella sp. HS2, where nitrogen in the growth environment is depleted naturally via consumption. To enhance both biomass and lipid productivity this strategy explored supplementation of additional P from 50% to 2500% of the initial concentration at the start of N-limited second stage of growth. The results of the optimization study in photobioreactor (PBR) showed that supplementing 500% of initial P and 100% of initial other nutrients (O) (N0-P500-O100) on 5th day showed the maximum biomass productivity of 774.4 mg L-1 d-1. It was observed that Chlorella sp. HS2 grown in PBR yielded higher biomass (3.8 times), lipid (6.1 times) and carbohydrate (5.5 times) productivity in comparison to the open raceway ponds (ORP) study, under optimum nutrient and carbon supply condition. The maximum lipid (289.6 mg L-1 d-1) and carbohydrate (219.2 mg L-1 d-1) productivities were obtained in TPBR-3, which were 1.9 and 1.3 times higher than that of TPBR-2 (+ve control) and 9.6 and 3.7 times higher than that of TPBR-1 (-ve control), respectively. Fatty acid mainly composed of C16/C18 (84.5%-85.7%), which makes the microalgal oil suitable for biofuel production. This study concluded that feeding excess amount of P is an effective and scalable strategy to improve the biomass and lipid productivity of CTS cultivation.


Assuntos
Chlorella , Microalgas , Biocombustíveis , Biomassa , Fósforo , Fotobiorreatores
19.
J Environ Manage ; 273: 111096, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32734892

RESUMO

Environmental sustainability criteria and rising energy demands, exhaustion of conventional resources of energy followed by environmental degradation due to abrupt climate changes have shifted the attention of scientists to seek renewable sources of green and clean energy for sustainable development. Bioenergy is an excellent alternative since it can be applied for several energy-requirements after utilizing suitable conversion methodology. This review elucidates all aspects of biofuels (bioethanol, biodiesel, and butanol) and their sustainability criteria. The principal focus is on the latest developments in biofuel production chiefly stressing on the role of nanotechnology. A plethora of investigations regarding the emerging techniques for process improvement like integration methods, less energy-intensive distillation techniques, and bioengineering of microorganisms are discussed. This can assist in making biofuel-production in a real-world market more economically and environmentally viable.


Assuntos
Biocombustíveis , Microalgas , Bioengenharia , Biotecnologia , Conservação dos Recursos Naturais
20.
Environ Pollut ; 266(Pt 2): 115264, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32771839

RESUMO

Biodiesel is considered as a valuable and less toxic alternative to diesel. However, cellular and molecular effects of repeated exposure to biodiesel emissions from a recent engine equipped with a diesel particle filter (DPF) remain to be characterized. To gain insights about this point, the lung transcriptional signatures were analyzed for rats (n = 6 per group) exposed to filtered air, 30% rapeseed biodiesel (B30) blend or reference diesel (RF0), upstream and downstream a DPF, for 3 weeks (3 h/day, 5 days/week). Genomic analysis revealed a modest regulation of gene expression level (lower than a 2-fold) by both fuels and a higher number of genes regulated downstream the DPF than upstream, in response to either RF0 or to B30 exhaust emissions. The presence of DPF was found to notably impact the lung gene signature of rats exposed to B30. The number of genes regulated in common by both fuels was low, which is likely due to differences in concentrations of regulated pollutants in exhausts, notably for compound organic volatiles, polycyclic aromatic hydrocarbons, NO or NOx. Nevertheless, we have identified some pathways that were activated for both exhaust emissions, such as integrin-, IGF-1- and Rac-signaling pathways, likely reflecting the effects of gas phase products. By contrast, some canonical pathways relative to "oxidative phosphorylation" and "mitochondrial dysfunction" appear as specific to B30 exhaust emission; the repression of transcripts of mitochondrial respiratory chain in lung of rats exposed to B30 downstream of DPF supports the perturbation of mitochondria function. This study done with a recent diesel engine (compliant with the European IV emission standard) and commercially-available fuels reveals that the diesel blend composition and the presence of an after treatment system may modify lung gene signature of rats repeatedly exposed to exhaust emissions, however in a rather modest manner.


Assuntos
Poluentes Atmosféricos/análise , Biocombustíveis/análise , Animais , Gasolina/análise , Material Particulado/análise , Ratos , Transcriptoma , Emissões de Veículos/análise
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