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1.
Environ Monit Assess ; 194(2): 81, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013799

RESUMO

Biomass combustion in indoor kitchens contributes a lot to the PM2.5 exposure burden among millions of people worldwide. Emitted potential pollutants from the biomass combustion oven may enormously degrade indoor air quality during cooking time and impact crowded rooms with inadequate indoor ventilation. The concept of developing a "ventilation index" may be a valuable alternative to assess indoor air quality. A new empirical formula of the ventilation index has been proposed recently, in which multiple studies need to be validated by various studies. This study is a part of the validation process and has ended up with supportive evidence-based insight into residential indoor air quality. Ninety-three households were selected from 25 villages of Tamil Nadu, India, to monitor the parameters required to apply in the empirical formula. However, the association between indoor air velocity and PM2.5 (considered a surrogate component of indoor air quality) was focused on emphatically. Other important variables, e.g., used amount of biomass cooking fuel, kitchen room index, room temperature, and relative humidity, were also monitored to observe the ventilation index. Indoor PM2.5 data were compared categorically with variable air velocities. Those who were using only biomass for cooking in indoor kitchens were recruited in the study. The air pollution exposure burden among the community population is expected to be minimized when the desired ventilation index is optimized and applied in configured kitchens and living rooms. Then, it may attract government policy to accept the ventilation index as a critical parameter for green housing schemes.


Assuntos
Poluição do Ar em Ambientes Fechados , Poluição do Ar em Ambientes Fechados/análise , Biomassa , Culinária , Monitoramento Ambiental , Humanos , Índia , Material Particulado/análise
2.
Microb Cell Fact ; 21(1): 5, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34983541

RESUMO

BACKGROUND: The filamentous fungus Trichoderma reesei is a widely used workhorse for cellulase production in industry due to its prominent secretion capacity of extracellular cellulolytic enzymes. However, some key components are not always sufficient in this cellulase cocktail, making the conversion of cellulose-based biomass costly on the industrial scale. Development of strong and efficient promoters would enable cellulase cocktail to be optimized for bioconversion of biomass. RESULTS: In this study, a synthetic hybrid promoter was constructed and applied to optimize the cellulolytic system of T. reesei for efficient saccharification towards corncob residues. Firstly, a series of 5' truncated promoters in different lengths were established based on the strong constitutive promoter Pcdna1. The strongest promoter amongst them was Pcdna1-3 (- 640 to - 1 bp upstream of the translation initiation codon ATG), exhibiting a 1.4-fold higher activity than that of the native cdna1 promoter. Meanwhile, the activation region (- 821 to - 622 bp upstream of the translation initiation codon ATG and devoid of the Cre1-binding sites) of the strong inducible promoter Pcbh1 was cloned and identified to be an amplifier in initiating gene expression. Finally, this activation region was fused to the strongest promoter Pcdna1-3, generating the novel synthetic hybrid promoter Pcc. This engineered promoter Pcc drove strong gene expression by displaying 1.6- and 1.8-fold stronger fluorescence intensity than Pcbh1 and Pcdna1 under the inducible condition using egfp as the reporter gene, respectively. Furthermore, Pcc was applied to overexpress the Aspergillus niger ß-glucosidase BGLA coding gene bglA and the native endoglucanase EG2 coding gene eg2, achieving 43.5-fold BGL activity and 1.2-fold EG activity increase, respectively. Ultimately, to overcome the defects of the native cellulase system in T. reesei, the bglA and eg2 were co-overexpressed under the control of Pcc promoter. The bglA-eg2 double expression strain QPEB70 exhibited a 178% increase in total cellulase activity, whose cellulase system displayed 2.3- and 2.4-fold higher saccharification efficiency towards acid-pretreated and delignified corncob residues than the parental strain, respectively. CONCLUSIONS: The synthetic hybrid promoter Pcc was generated and employed to improve the cellulase system of T. reesei by expressing specific components. Therefore, construction of synthetic hybrid promoters would allow particular cellulase genes to be expressed at desired levels, which is a viable strategy to optimize the cellulolytic enzyme system for efficient biomass bioconversion.


Assuntos
Celulase/genética , Celulase/metabolismo , Hypocreales/genética , Hypocreales/metabolismo , Regiões Promotoras Genéticas , Zea mays/metabolismo , Biomassa , Celulose/metabolismo , Proteínas Fúngicas/genética , Zea mays/microbiologia
3.
Arch Microbiol ; 204(2): 128, 2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-34997859

RESUMO

Remazol Brilliant Blue R (RBBR) is a widely used carcinogenic and toxic dye. This study focused on RBBR dye removal using chemically modified and unmodified Yarrowia lipolytica biomass. RBBR dye biosorption studies were carried out as a function of pH, initial dye concentration, biosorbent dose, contact time, and temperature. The pH of the aqueous solution strongly influenced the biosorption percent of RBBR dye. The highest dye biosorption capacity yield was obtained at pH 2-3 range. It has been found that the adsorption capacity is quite low at higher pH values. No differences were found between chemically modified and unmodified biomass in terms of RBBR dye biosorption capacity. In the first 15 min, almost 50% RBBR dye was removed from the solution and reached equilibrium within180 min at pH 2. Biosorption isotherm obeyed Langmuir isotherm model and pseudo-second-order kinetic model.


Assuntos
Poluentes Químicos da Água , Yarrowia , Antraquinonas , Biomassa , Concentração de Íons de Hidrogênio , Cinética , Termodinâmica
4.
Curr Microbiol ; 79(2): 40, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34982231

RESUMO

In this work, primary brewery wastewater (PBWW) and secondary brewery wastewater (SBWW) separately, or mixed at the ratios of 1:1 (PBWW:SBWW) and 1:7 (PBWW:SBWW), with or without supplementation with sugarcane molasses (SCM), were used as culture media for lipid production by a mixed culture of the oleaginous yeast Rhodosporidium toruloides NCYC 921 and the microalgae Tetradesmus obliquus (ACOI 204/07). Flow cytometry was used to understand the dynamics of the two micro-organisms during the mixed cultures evolution, as well as to evaluate the physiological states of each micro-organism, in order to assess the impact of the different brewery effluent media composition on the microbial consortium performance. Both brewery wastewaters (primary and secondary) without supplementation did not allow R. toruloides heterotrophic growth. Nevertheless, all brewery wastewater media, with and without SCM supplementation, allowed the microalgae growth, although the yeast was the dominant population. The maximum total biomass concentration of 2.17 g L-1 was achieved in the PBWW mixed cultivation with 10 g L-1 of SCM. The maximum lipid content (14.86% (w/w DCW)) was obtained for the mixed culture developed on SBWW supplemented with 10 g L-1 of SCM. This work demonstrated the potential of using brewery wastewater supplemented with SCM as a low-cost culture medium to grow R. toruloides and T. obliquus in a mixed culture for brewery wastewater treatment with concomitant lipid production.


Assuntos
Microalgas , Rhodotorula , Biomassa , Lipídeos , Águas Residuárias
5.
Appl Microbiol Biotechnol ; 106(2): 635-645, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35015141

RESUMO

Fluorescence spectroscopy offers a cheap, simple, and fast approach to monitor poly(3-hydroxybutyrate) (PHB) formation, a biodegradable polymer belonging to the biodegradable polyester class polyhydroxyalkanoates. In the present study, a fluorescence and side scatter-based spectroscopic setup was developed to monitor in situ biomass, and PHB formation of biotechnological applied Cupriavidus necator strain. To establish PHB quantification of C. necator, the dyes 2,2-difluoro-4,6,8,10,12-pentamethyl-3-aza-1-azonia-2-boranuidatricyclo[7.3.0.03,7]dodeca-1(12),4,6,8,10-pentaene (BODIPY493/503), ethyl 5-methoxy-1,2-bis(3-methylbut-2-enyl)-3-oxoindole-2-carboxylate (LipidGreen2), and 9-(diethylamino)benzo[a]phenoxazin-5-one (Nile red) were compared with each other. Fluorescence staining efficacy was obtained through 3D-excitation-emission matrix and design of experiments. The coefficients of determination were ≥ 0.98 for all three dyes and linear to the high-pressure liquid chromatography obtained PHB content, and the side scatter to the biomass concentration. The fluorescence correlation models were further improved by the incorporation of the biomass-related side scatter. Afterward, the resulting regression fluorescence models were successfully applied to nitrogen-deficit, phosphor-deficit, and NaCl-stressed C. necator cultures. The highest transferability of the regression models was shown by using LipidGreen2. The novel approach opens a tailor-made way for a fast and simultaneous detection of the crucial biotechnological parameters biomass and PHB content during fermentation. KEY POINTS: • Intracellular quantification of PHB and biomass using fluorescence spectroscopy. • Optimizing fluorescence staining conditions and 3D-excitation-emission matrix. • PHB was best obtained by LipidGreen2, followed by BODIPDY493/503 and Nile red.


Assuntos
Cupriavidus necator , Ácido 3-Hidroxibutírico , Biomassa , Hidroxibutiratos , Poliésteres , Espectrometria de Fluorescência
6.
J Plant Res ; 135(1): 69-79, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34973093

RESUMO

Assessing long-term changes in the biomass of old-growth forests with consideration of climate effects is essential for understanding forest ecosystem functions under a changing climate. Long-term biomass changes are the result of accumulated short-term changes, which can be affected by endogenous processes such as gap filling in small-scale canopy openings. Here, we used 26 years (1993-2019) of repeated tree census data in an old-growth, cool-temperate, mixed deciduous forest that contains three topographic units (riparian, denuded slope, and terrace) in northern Japan to document decadal changes in aboveground biomass (AGB) and their processes in relation to endogenous processes and climatic factors. AGB increased steadily over the 26 years in all topographic units, but different tree species contributed to the increase among the topographic units. AGB gain within each topographic unit exceeded AGB loss via tree mortality in most of the measurement periods despite substantial temporal variation in AGB loss. At the local scale, variations in AGB gain were partially explained by compensating growth of trees around canopy gaps. Climate affected the local-scale AGB gain: the gain was larger in the measurement periods with higher mean air temperature during the current summer but smaller in those with higher mean air temperature during the previous autumn, synchronously in all topographic units. The influences of decadal summer and autumn warming on AGB growth appeared to be counteracting, suggesting that the observed steady AGB increase in KRRF is not fully explained by the warming. Future studies should consider global and regional environmental factors such as elevated CO2 concentrations and nitrogen deposition, and include cool-temperate forests with a broader temperature range to improve our understanding on biomass accumulation in this type of forests under climate change.


Assuntos
Ecossistema , Florestas , Biomassa , Japão , Árvores
7.
An Acad Bras Cienc ; 94(1): e20200457, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35043847

RESUMO

The assessment of ecosystem functions in Cerrado is important to implement practices of conservation. Recently, a 'rapid ecosystem function assessment' (REFA) for measuring ecosystem functions has been proposed and tested as a suitable method. Thus, this study aimed to assess the proxies of ecosystem functions of three physiognomies of Cerrado through REFA. This method was applied in three different preserved physiognomies of Cerrado from Northeastern, Brazil, namely: Campo Graminoide (CG), Cerrado Stricto Sensu (CSS), and Cerradão (CD). All proxies for the selected ecosystem functions differed between sites and seasons. The above- and belowground primary productivity and microbial biomass C were higher in CD than in CSS and CG. The above- and belowground secondary productivity and decomposition were higher and similar in CD and CSS as compared to CG. The principal component analysis explained 89.8% of the data variation and clustered the majority of ecosystem functions with CD, in both seasons and CSS in the wet season. The proxies of ecosystem functions measured through REFA showed differences between the physiognomies of Cerrado. Since each physiognomy of Cerrado presents different plant richness and diversity, and soil conditions, these characteristics contribute to influencing multiple ecosystem functions.


Assuntos
Ecossistema , Fisiognomia , Biomassa , Brasil , Solo , Microbiologia do Solo
8.
J Biotechnol ; 343: 120-127, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34896159

RESUMO

Co-culture of microalgae and microorganisms, supported with the resulting synergistic effects, can be used for wastewater treatment, biomass production, agricultural applications and etc. Therefore, this study aimed to explore the role of Bacillus subtilis (B. subtilis) in tolerance against the harsh environment of seafood wastewater, at which these microalgal-bacterial flocs were formed by microalgae cultivation. In this present study, B. subtilis isolated from the cultivation medium of Chlorella vulgaris and exposed to different salinity (0.1-4% w/v sodium chloride) and various pH range to determine the tolerant ability and biofilm formation. Interestingly, this bacteria strain that isolated from microalgae cultivation medium showed the intense viability in the salt concentration exceeding up to 4% (w/v) NaCl but demonstrated the decrease in cell division as environmental culture undergoing over pH 10. Cell viability was recorded higher than 71% and 92% for B. subtilis inoculum in media with salt concentration greater than 20 gL-1 and external pH 6.5-9, respectively. This showed that B. subtilis isolated from microalgal-bacteria cocultivation exhibited its tolerant ability to survive in the extremely harsh conditions and thus, mitigating the stresses due to salinity and pH.


Assuntos
Chlorella vulgaris , Microalgas , Microbiota , Bacillus subtilis , Biomassa , Águas Residuárias
9.
J Environ Sci (China) ; 113: 118-131, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34963521

RESUMO

Concurrent ground-level ozone (O3) pollution and anthropogenic nitrogen (N) deposition can markedly influence dynamics and productivity in forests. Most studies evaluating the functional traits responses of rapid-turnover organs to O3 have specifically examined leaves, despite fine roots are another major source of soil carbon and nutrient input in forest ecosystems. How elevated O3 levels impact fine root biomass and biochemistry remains to be resolved. This study was to assess poplar leaf and fine root biomass and biochemistry responses to five different levels of O3 pollution, while additionally examining whether four levels of soil N supplementation were sufficient to alter the impact of O3 on these two organs. Elevated O3 resulted in a more substantial reduction in fine root biomass than leaf biomass; relative to leaves, more biochemically-resistant components were present within fine root litter, which contained high concentrations of lignin, condensed tannins, and elevated C:N and lignin: N ratios that were associated with slower rates of litter decomposition. In contrast, leaves contained more labile components, including nonstructural carbohydrates and N, as well as a higher N:P ratio. Elevated O3 significantly reduced labile components and increased biochemically-resistant components in leaves, whereas they had minimal impact on fine root biochemistry. This suggests that O3 pollution has the potential to delay leaf litter decomposition and associated nutrient cycling. N addition largely failed to affect the impact of elevated O3 levels on leaves or fine root chemistry, suggesting that soil N supplementation is not a suitable approach to combating the impact of O3 pollution on key functional traits of poplars. These results indicate that the significant differences in the responses of leaves and fine roots to O3 pollution will result in marked changes in the relative belowground roles of these two litter sources within forest ecosystems, and such changes will independently of nitrogen load.


Assuntos
Nitrogênio , Ozônio , Biomassa , Ecossistema , Florestas , Ozônio/toxicidade , Folhas de Planta , Raízes de Plantas , Solo
10.
Chemosphere ; 286(Pt 3): 131867, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34411931

RESUMO

A broad range of conventional biomass and plastic waste types was considered and their air gasification process was modeled using a Gibbs free energy minimization coupled with Lagrange multiplier approach. The comparison between the performances of biomass and plastic waste gasification is the main issue of this study. Another important novelty and contribution of this study is analytical hierarchy process/technique for order performance by similarity to the ideal solution coupled method that is employed in gasification of conventional biomass and plastic waste, to prioritize the considered criteria and to select the best feedstock for gasification. Hydrogen production was linearly reduced in the case of conventional biomass with an in increase in the equivalence ratio; however, there was an optimum equivalence ratio to achieve the highest hydrogen production in plastic waste gasification. Plastic waste had a higher low heating value compared to conventional biomass. However, carbon monoxide and nitrogen production from conventional biomass was smaller than from plastic waste. Ten types of feedstock, comprising six types of conventional biomass and four types of plastic waste, were selected as alternatives. The multi-criteria decision analysis coupled method revealed that waste polypropylene and polyethylene were the best alternatives.


Assuntos
Monóxido de Carbono , Plásticos , Biomassa , Técnicas de Apoio para a Decisão
11.
J Colloid Interface Sci ; 606(Pt 1): 817-825, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34425269

RESUMO

The carbon pore structure could have a significant effect on supercapacitor performance; however, this effect has not yet been systematically studied. A facile approach for synthesizing porous, ultrathin carbon sheets while rationally tuning the ratio of micro-to meso-pores via partial corrosion has been developed for the fabrication of high-performance devices. The prepared carbon from biomass with an optimal ratio of micro- to meso-pores has a large specific surface area of 1785 m2 g -1, a high specific capacitance of 447F g -1 at 0.5 A g-1, a high energy density of 15.5-9.7 Wh kg-1, and an excellent power density of 0.062-6.24 kW kg-1. After 10,000 charge-discharge cycles, the capacitance retention was maintained at 95%, which exceeded most of the biomass-carbon-based capacitors. Volcano relationships were found to exist through plots of both specific surface area and specific capacitance versus the micro-to meso-pore ratio. An enhancement mechanism with a rational pore structure is proposed, which not only networks micropores to remove died-end micropores to achieve the largest specific active surface area and high specific capacitance but also realizes fast mass-transport channels, resulting in high power density. This work provides an effective approach based on waste re-use by tuning a rational pore structure for achieving high energy/power density toward green energy applications with universal significance.


Assuntos
Carbono , Biomassa , Capacitância Elétrica , Porosidade
12.
Chemosphere ; 286(Pt 3): 131961, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34426294

RESUMO

Biochar produced from the thermochemical conversion of biomass, provides a green and sustainable platform for the preparation of various functional carbon materials (porous carbon, heteroatom doped biochar, carbon nanotubes, graphene, carbon quantum dots, etc.) towards advanced application. Their preparation involves the physical as well as chemical activation of biochar or directly from the biomass. The inherent versatile physicochemical properties of these versatile materials have been explored for the construction of the electrochemical energy storage devices like supercapacitors. In the present review, the various methodologies for the preparation of various biomass-derived carbon materials are summarized. Further utilization of these materials in supercapacitor electrodes and the properties associated with their charge storage ability, along with associated challenges and perspectives are also discussed.


Assuntos
Grafite , Nanotubos de Carbono , Biomassa , Eletrodos , Porosidade
13.
Chemosphere ; 286(Pt 3): 131935, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34426295

RESUMO

Cu-NH3 bearing effluents arise from electroplating and metal extraction industries, requiring innovative and sustainable Cu recovery technologies to reduce their adverse environmental impact. CO32- and Zn are often co-occurring, and thus, selective Cu recovery from these complex liquid streams is required for economic viability. This study assessed 23 sustainable biosorbents classified as tannin-rich, lignin-rich, chitosan/chitin, dead biomass, macroalgae or biochar for their Cu adsorption capacity and selectivity in a complex NH3-bearing bioleachate. Under a preliminary screen with 12 mM Cu in 1 M ammoniacal solution, most biosorbents showed optimal Cu adsorption at pH 11, with pinecone remarkably showing high removal efficiencies (up to 68%) at all tested pH values. Further refinements on select biosorbents with pH, contact time, and presence of NH3, Zn and CO32- showed again that pinecone has a high maximum adsorption capacity (1.07 mmol g-1), worked over pH 5-12 and was Cu-selective with 3.97 selectivity quotient (KCu/Zn). Importantly, pinecone performance was maintained in a real Cu/NH3/Zn/CO32- bioleachate, with 69.4% Cu removal efficiency. Unlike synthetic adsorbents, pinecones require no pre-treatment, which together with its abundance, selectivity, and efficiency without the need for prior NH3 removal, makes it a competitive and sustainable Cu biosorbent for complex Cu-NH3 bearing streams. Overall, this study demonstrated the potential of integrating bioleaching and biosorption as a clean Cu recovery technology utilizing only sustainable resources (i.e., bio-lixiviant and biosorbents). This presents a closed-loop approach to Cu extraction and recovery from wastes, thus effectively addressing elemental sustainability.


Assuntos
Cobre , Poluentes Químicos da Água , Adsorção , Biomassa , Galvanoplastia , Concentração de Íons de Hidrogênio , Cinética , Poluentes Químicos da Água/análise
14.
Chemosphere ; 287(Pt 1): 131944, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34438210

RESUMO

Depletion of non-renewable feedstock and severe wastewater pollution due to human activities have created negative impact to living organisms. The potential solution is to implement wastewater treatment and bioelectricity production through algae-based microbial fuel cell. The algae biomass produced from microbial fuel cell could be further processed to generate biofuels through their unique compositions. The consumption of nutrients in wastewater through algae cultivation and biomass produced to be utilized for energy supply have showed the potential of algae to solve the issues faced nowadays. This review introduces the background of algae and mitigation of wastewater using algae as well as the bioenergy status in Malaysia. The mechanisms of nutrient assimilation such as nitrogen, phosphorus, carbon, and heavy metals are included, followed by the application of algae in microbial fuel cell's chambers. Lastly, the status of algae for bioenergy production are covered.


Assuntos
Microalgas , Biocombustíveis , Biomassa , Humanos , Fósforo , Águas Residuárias
15.
Chemosphere ; 286(Pt 3): 131901, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34449323

RESUMO

Mustard waste briquettes are commercially used as a fuel for power production in boilers, whereas the thermal kinetics of the biomass plays a vital role in deciding the process parameters. The pyrolysis process converts biomass to value-added products such as biochar, bio-oil, and hydrocarbon gases based on the heating rates and temperature. To enhance the pyrolytic activity of mustard biomass, magnetically separable and reusable FeNi alloy catalyst is investigated. The thermo-conversion properties are studied under variable heating rates with 2 and 10% FeNi particles prepared through a facile chemical reduction technique. Thermal kinetics is computed using Flynn-Wall-Ozawa (FOW) and Kissinger-Akahira-Sunose (KAS) methods. The activation energies calculated using FOW and KAS methods increase with FeNi addition in mustard while the calorific value decreases. The FeNi alloy particles with the spike-like morphology provide better metal-biomass binding resulting in higher activation energy and facilitates the easy decomposition of lignin. The 10% FeNi -mustard shows uniform conversion independent of heating rates, suitable for magnetically recoverable catalytic pyrolysis. Response surface methodology analysis predicts optimum conversion for 10% FeNi added mustard and less significance for the heating rates in concurrence with the experiments. Artificial neural network utilized to predict and validate mass loss for mustard biomass exhibits best fit for the three neural hidden layer and one output layered topology.


Assuntos
Mostardeira , Níquel , Biomassa , Ferro , Cinética , Termogravimetria
16.
Chemosphere ; 287(Pt 1): 131998, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34450373

RESUMO

The sulfur-based autotrophic denitrification (SAD) and the solid organic carbon-based denitrification processes are both efficient techniques to remove nitrate from wastewater, and the hydrogen ions generated by the SAD process would be consumed in the heterotrophic denitrification process. Therefore, it is possible to improve the denitrification capacity when the solid organic carbon was added into a SAD reactor. In this study, corncob powder and sawdust powder were selected as solid organic carbon sources, and the sulfur-based autotrophic denitrification integrated biomass-based heterotrophic denitrification system was formed (SBD). The laboratory and field experiments showed that SBD could shorten the start-up period, decrease the sulfate productivity, and maintain a good denitrification performance when treated wastewater. According to the field experiment results, when the HRT was 1 h, the effluent total nitrogen (TN) concentration was always lower than 15 mg L-1. In addition, nitrite inhibition was observed when the concentration of nitrite in the reactors reached above 30 mg L-1. The mixture of elemental sulfur powder, shell powder, corncob powder, and sawdust powder with a mass ratio of 6:2:1:1 was the optimal filter for the SBD system, with an average nitrate reduction rate (NAR) of 420 mg NO3-N·L-1·d-1 obtained at the end of the study. During the whole operation, the major autotrophs in the SBD systems were Thermomonas, Ferritrophicum, and Thiobacillus, while the major heterotrophs were Saprospiraceae, Ferruginibacter, Dokdonella, and Simplicispira. Overall, the SBD system was a feasible and practically favorable way to remove nitrate from wastewater.


Assuntos
Desnitrificação , Águas Residuárias , Processos Autotróficos , Biomassa , Reatores Biológicos , Estudos de Viabilidade , Nitratos , Nitrogênio , Enxofre
17.
Bioresour Technol ; 343: 126075, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34606922

RESUMO

Oligosaccharides are low-molecular-weight carbohydrates with crucial physical, chemical, and physiological properties, which are increasingly important in the fields of food, pharmaceuticals, cosmetics, and biomedicine. Pretreating biomass in a cost-effective way is a significant challenge for oligosaccharides research. Hydrothermal pretreatment is a potentially eco-friendly technology to obtain oligosaccharides by deconstructing biomass. In this work, we compared the differences between hydrothermal pretreatment and the traditional pretreatment method. The fundamentals and classification of hydrothermal pretreatment, as well as the latest studies on hydrothermal preparation of oligosaccharides, were further reviewed and evaluated to provide a theoretical basis for the production and application of oligosaccharides. Some challenges and future trends to develop green and large-scale hydrothermal pretreatment were proposed for the production of oligosaccharides.


Assuntos
Oligossacarídeos , Vapor , Biomassa , Carboidratos , Peso Molecular
18.
Bioresour Technol ; 343: 126069, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34606926

RESUMO

This study aims to evaluate the performance of C. vulgaris microalgae to simultaneously recover nutrients from sludge centrate and produce biomass in a membrane photobioreactor (MPR). Microalgae growth and nutrient removal were evaluated at two different nutrient loading rates (sludge centrate). The results show that C. vulgaris microalgae could thrive in sludge centrate. Nutrient loading has an indiscernible impact on biomass growth and a notable impact on nutrient removal efficiency. Nutrient removal increased as the nutrient loading rate decreased and hydraulic retention time increased. There was no membrane fouling observed in the MPR and the membrane water flux was fully restored by backwashing using only water. However, the membrane permeability varies with the hydraulic retention time (HRT) and biomass concentration in the reactor. Longer HRT offers higher permeability. Therefore, it is recommended to operate the MPR system in lower HRT to improve the membrane resistance and energy consumption.


Assuntos
Fotobiorreatores , Esgotos , Biomassa , Nutrientes , Águas Residuárias/análise
19.
J Environ Manage ; 301: 113854, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34607141

RESUMO

Insights into thermal degradation behaviour, kinetics, reaction mechanism, possible synergism, and thermodynamic analysis of co-pyrolysis of carbonaceous materials are crucial for efficient design of co-pyrolysis reactor systems. Present study deals with comprehensive kinetics and thermodynamic investigation of co-pyrolysis of petroleum coke (PC) and banana leaves biomass (BLB) for realizing the co-pyrolysis potential. Thermogravimetric non-isothermal studies have been performed at 10, 20, and 30 °C/min heating rates. Synergistic effect between PC and BLB was determined by Devolatilization index (Di) and mass loss method. Kinetic parameters were estimated using seven model-free methods. Standard activation energy for PC + BLB blend from FWO, KAS, Starink, and Vyazovkin methods was ≈165 kJ/mol and that from Friedman and Vyazovkin advanced isoconversional methods was ≈171 kJ/mol. The frequency factor calculated for the blend from Kissinger method was found to be in the range of 106-1016s-1. Devolatilization index (Di) showed synergistic effect of blending. The data pertaining to co-pyrolysis was found to fit well with R2 (second order) and D3 (three dimensional) from Z(α) master plot. Thermodynamic parameters, viz. ΔH ≈ 163 kJ/mol and ΔG ≈ 151 kJ/mol were calculated to determine the feasibility and reactivity of the co-pyrolysis process. The results are expected to be useful in the design of petcoke and banana leaves biomass co-pyrolysis systems.


Assuntos
Coque , Musa , Petróleo , Biomassa , Cinética , Folhas de Planta , Pirólise , Termodinâmica , Termogravimetria
20.
Chemosphere ; 287(Pt 4): 132458, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34610377

RESUMO

Over the past decade, there has been a surge of interest in using char (hydrochar or biochar) derived from biomass as persulfate (PS, either peroxymonosulfate or peroxydisulfate) activator for anthropogenic pollutants removal. While extensive investigation showed that char could be used as a PS activator, its sustainability over prolonged application is equivocal. This review provides an assessment of the knowledge gap related to the sustainability of char as a PS activator. The desirable char properties for PS activation are identified, include the high specific surface area and favorable surface chemistry. Various synthesis strategies to obtain the desirable properties during biomass pre-treatment, hydrochar and biochar synthesis, and char post-treatment are discussed. Thereafter, factors related to the sustainability of employing char as a PS activator for anthropogenic pollutants removal are critically evaluated. Among the critical factors include performance uncertainty, competing adsorption process, char stability during PS activation, biomass precursor variation, scalability, and toxic components in char. Finally, some potential research directions are provided. Fulfilling the sustainability factors will provide opportunity to employ char as an economical and efficient catalyst for sustainable environmental remediation.


Assuntos
Carvão Vegetal , Adsorção , Biomassa , Catálise
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