3,414 research outputs found
A multi-step physicochemical-biotechnological approach for the valorization of olive mill wastewaters
No full textWaste valorization processes carried out through integrated multi-step biorefinery approaches can allow a massive exploitation of the waste organic matter. Olive mill wastewaters (OMWs) are agro-industrial wastes of a high environmental concern. A relevant part of their high COD is typically due to polyphenolic compounds, which are known to be toxic if concentrated to such extents. On the other hands, polyphenols are natural antioxidants of special relevance for several industrial sectors. Therefore, their recovery from OMWs provides the double opportunity to obtain high-added value biomolecules and to reduce the phytotoxicity of the effluent. To such an aim, an effective solid phase extraction process was recently developed [1]. The first aim of the present work was to define a protocol for the recovery and reuse of both the adsorbent (Amberlite XAD16 non-polar resin) and extraction solvent (ethanol), in order to verify the feasibility of a possible process scale-up. Very encouraging results were obtained: ethanol was recovered by means of a rotary evaporator, thus obtaining a concentrated phenolic mixture, whose antioxidant properties were demonstrated via ORAC and DPPH assays; furthermore, after its employment, the resin was washed with a sulphuric acid solution and regenerated: no significant losses of the resin adsorption capabilities were observed after 10 operation cycles. The exploitation of the OMW organic matter was further addressed toward the biotechnological production of biobased chemicals, such as H2 and volatile fatty acids (VFAs), which represent a feasible substrate for aerobic bacteria able to produce and store biopolymers such as polyhydroxyalkanoates (PHAs) [3]. A non conventional anaerobic digestion process carried out under acidogenic conditions for the obtainment of VFAs from dephenolized OMWs was recently developed [4]. The second aim of the present study was a further assessment of that process, with the aim of minimizing the process HRT. At a HRT = 5 days, a stable process capable of an effective bioconversion of the OMW organic matter into VFAs was obtained, with a VFA final concentration of about 19.7 gCOD/L, representing about 83% of the overall effluent COD.
References
[1] Bertin, L., Ferri, F., Scoma, A., Marchetti, L., Fava, F.: Recovery of high added value natural polyphenols from actual olive mill wastewater through solid phase extraction. Chem. Eng. J. 171, 1287-1293 (2011)
[2] Beccari, M., Bertin, L., Dionisi, D., Fava, F., Lampis, S., Majone, M., Valentino, F., Vallini, G., Villano, M.,: Exploiting olive oil mill effluents as a renewable resource for production of biodegradable polymers through a combined anaerobiceaerobic process. J. Chem. Technol. Biotechnol. 84, 901-908 (2009)
[3] Scoma, A., Bertin, L., Zanaroli, G., Fraraccio, S., Fava, F.: A physicochemical–biotechnological approach for an integrated valorization of olive mill wastewater. Biores. Technol. 102, 10273-10279 (2011
Teor de compostos cianogênicos em linhagens de feijão-fava (Phaseolus Lunatus L.).
No full textO feijão-fava (Phaseolus lunatus L.), também conhecido como feijão-de-lima, fava-de-lima ou simplesmente fava destaca-se entre as leguminosas tradicionalmente mais consumidas, sendo utilizado como alternativa em substituição a outros alimentos proteicos. A despeito de suas excelentes propriedades nutricionais, o feijão-fava apresenta compostos antinutricionais que reduzem a biodisponibilidade de minerais, tais como glicosídeos cianogênicos. O teor de compostos cianogênicos (HCN) em feijão-fava pode variar entre diferentes linhagens e até mesmo entre plantas da mesma linhagem, dependendo das condições de cultivo e do estágio de maturação
Methyl-β-cyclodextrin-enhanced solubilization and aerobic biodegradation of polychlorinated biphenyls in two aged-contaminated soils
No full textThe bioremediation of aged polychlorinated biphenyl (PCB)-contaminated soils is adversely affected by the low bioavailability of the pollutants. Randomly methylated-β-cyclodextrins (RAMEB) were tested as a potential PCB-bioavailability-enhancing agent in the aerobic treatment of two aged-contaminated soils. The soils, contaminated by about 890 and 8500 mg/kg of Aroclor 1260 PCBs, were amended with biphenyl (4 g/kg), inorganic nutrients (to adjust their C:N ratio to 20:1), and variable amounts of RAMEB (0%, 0.5%, or 1.0% [w/w]) and treated in both aerobic 3-L solid-phase reactors and 1.5-L packed-bed loop reactors for 6 months. Notably, significant enhancement of the PCB biodegradation and dechlorination, along with a detectable depletion of the initial soil ecotoxicity, were generally observed in the RAMEB-treated reactors of both soils. RAMEB effects were different in the two soils, depending upon the treatment conditions employed, and generally increased proportionally with the concentration at which RAMEB was applied. RAMEB, which was slowly metabolized by the soil's aerobic microorganisms, was found to markedly enhance the occurrence of the indigenous aerobic, cultivable biphenyl-growing bacteria harboring genes homologous to those of two highly specialized PCB degraders (i.e., bphABC genes of Pseudomonas pseudoalcaligenes KF707 and bphA1A2A3A4BC1 genes of Rhodococcus globerulus P6) and chlorobenzoic acid-degrading bacteria as well as the occurrence of PCBs in the water phase of the soil reactors. These findings indicate that RAMEB enhanced the aerobic bioremediation of the two soils by increasing the bioavailability of PCBs and the occurrence of specialized bacteria in the soil reactors. © 2003 Wiley Periodicals, Inc
PCB reductive dechlorination in sediments of Venice lagoon: preliminary characterization of dechlorinating microflora
No full textReductive dechlorination processes towards weathered PCBs were recently detected and characterized in marine sediments of the Porto Marghera area of Venice lagoon and tentatively ascribed to sulfate-reducing spore-forming bacteria1,2,3. To gain deeper insights on native microflora, enrichments were performed in the presence of exogenous PCBs, electron donors and antibiotics. Increasing PCB-dechlorination and sulfate reduction rates, as well as progressive decrease of methanogenic activity were observed throughout subculturing. H2 and short chain organic acids did not affect the process. However, their addition together with vancomycin or ampicillin, resulted in higher dechlorination rates and extents. This suggests that Dehalococcoides-like bacteria are involved in PCB dechlorination, even though involvement of sulfate-reducing bacteria cannot be excluded.
1. Fava, F.; Gentilucci, S.; Zanaroli, G. Chemosphere 2003, 53, 101-109. 2. Fava, F; Zanaroli, G; Young, L.Y. FEMS Microbiol. Ecol. 2003, 44, 309-318. 3. Zanaroli, G.; Pérez-Jiménez, J.R.; Young, L.Y.; Fava, F. Biodegradation 2006, 17, 19-27
A multi-step physicochemical-biotechnological approach for the valorization of olive mill wastewaters
No full textWaste valorization processes carried out through integrated multi-step biorefinery approaches can allow a massive exploitation of the waste organic matter. Olive mill wastewaters (OMWs) are agro-industrial wastes of a high environmental concern. A relevant part of their high COD is typically due to polyphenolic compounds, which are known to be toxic if concentrated to such extents. On the other hands, polyphenols are natural antioxidants of special relevance for several industrial sectors. Therefore, their recovery from OMWs provides the double opportunity to obtain high-added value biomolecules and to reduce the phytotoxicity of the effluent. To such an aim, an effective solid phase extraction process was recently developed [1]. The first aim of the present work was to define a protocol for the recovery and reuse of both the adsorbent (Amberlite XAD16 non-polar resin) and extraction solvent (ethanol), in order to verify the feasibility of a possible process scale-up. Very encouraging results were obtained: ethanol was recovered by means of a rotary evaporator, thus obtaining a concentrated phenolic mixture, whose antioxidant properties were demonstrated via ORAC and DPPH assays; furthermore, after its employment, the resin was washed with a sulphuric acid solution and regenerated: no significant losses of the resin adsorption capabilities were observed after 10 operation cycles. The exploitation of the OMW organic matter was further addressed toward the biotechnological production of biobased chemicals, such as H2 and volatile fatty acids (VFAs), which represent a feasible substrate for aerobic bacteria able to produce and store biopolymers such as polyhydroxyalkanoates (PHAs) [3]. A non conventional anaerobic digestion process carried out under acidogenic conditions for the obtainment of VFAs from dephenolized OMWs was recently developed [4]. The second aim of the present study was a further assessment of that process, with the aim of minimizing the process HRT. At a HRT = 5 days, a stable process capable of an effective bioconversion of the OMW organic matter into VFAs was obtained, with a VFA final concentration of about 19.7 gCOD/L, representing about 83% of the overall effluent COD.
References
[1] Bertin, L., Ferri, F., Scoma, A., Marchetti, L., Fava, F.: Recovery of high added value natural polyphenols from actual olive mill wastewater through solid phase extraction. Chem. Eng. J. 171, 1287-1293 (2011)
[2] Beccari, M., Bertin, L., Dionisi, D., Fava, F., Lampis, S., Majone, M., Valentino, F., Vallini, G., Villano, M.,: Exploiting olive oil mill effluents as a renewable resource for production of biodegradable polymers through a combined anaerobiceaerobic process. J. Chem. Technol. Biotechnol. 84, 901-908 (2009)
[3] Scoma, A., Bertin, L., Zanaroli, G., Fraraccio, S., Fava, F.: A physicochemical–biotechnological approach for an integrated valorization of olive mill wastewater. Biores. Technol. 102, 10273-10279 (2011
Acclimatization of methanogen consortium capable to digest relevant percentages of municipal solid waste in codigestion with cattle manure
No full textThe acclimatization of an anaerobic consortium capable of producing methane through the co-digestion of municipal solid waste (MSW) and cattle manure was achieved through a fed batch procedure1. Anaerobic microcosms consisting of 46 mL of pre-treated MSW were set up under strictly anaerobic conditions and statically incubated at 35°C. MSW volatile solids (VS) were from 60 to 100% of the mixture applied. Four successive 1-month batch experiments were performed by leaving 10% (v/v) of the digested sludge in the bottles and refilling them with the corresponding fresh cattle manure amended MSW. Biogas production and composition as well as VS, volatile fatty acids and electron acceptors occurring in the microcosms were investigated together with the structure and composition (via DGGE analysis) of microbial population responsible for the MSW digestion. Biogas and CH4 production increased significantly from the 1st to 4th batch experiment, especially where higher amounts of cattle manure were applied (i.e., about 160 mlCH4/gVS, representing the 41% of the total biogas produced, by digesting MSW with 60% of total VS).
1. Bertin, L.; Todaro, D.; Bettini, C.; Fava, F. Wat. Sci. Technol. 2008, 58(9), 1735-1742
Biodegradation of hydroxylated and methoxylated benzoic, phenylacetic and phenylpropenoic acids present in olive mill wastewaters by two bacterial strains
No full textTwo aerobic bacterial strains, a chlorophenol-degrading bacterium characterized in this work as a Ralstonia sp. LD35 on the basis of the sequence of the gene encoding for 16S ribosomal RNA, and Pseudomonas putida DSM 1868, capable of metabolizing 4-methoxybenzoic acid, were tested for their capacity to degrade monocyclic aromatic acids responsible for the toxicity of olive mill wastewaters (OMWs). Both strains possess interesting and complementary degradation capabilities in resting cell conditions: Ralstonia sp. LD35 was found to metabolize 4-hydroxybenzoic, 4-hydroxyphenylacetic, 3,4-dihydroxycinnamic and cinnamic acid, whereas DSM 1868 was capable of metabolizing 4-hydroxy-3-methoxybenzoic, 3,4-dimethoxybenzoic and 4-hydroxy-3,5-dimethoxybenzoic acid, as well as 4-hydroxybenzoic and 4-hydroxyphenylacetic acid. The kinetic parameters describing the growth of the two strains on the same compounds were determined in growing-cell batch conditions, and showed that both strains presented high affinity and high specific growth rates towards all assayed substrates. In addition, the two strains were capable of growing on and extensively biodegrading a mixture of monocyclic aromatic acids commonly found at high concentrations in OMWs, and of growing on a 20% dilution of a natural OMW. All these features make the two strains attractive candidates for the development of a biotechnological process for the biodegradation of aromatic compounds found in OMWs. © 2001 Éditions scientifiques et médicales Elsevier SAS
Biodegradation of synthetic and naturally occurring mixtures of mono-cyclic aromatic compounds present in olive mill wastewaters by two aerobic bacteria
No full textTwo bacterial strains, Ralstonia sp. LD35 and Pseudomonas putida DSM 1868, were assayed for their ability to degrade the monocyclic aromatic compounds commonly found in olive mill wastewaters (OMWs). The goal was to study the possibility of employing the two strains in the removal of these recalcitrant and toxic compounds from the effluents of anaerobic treatment plants fed with OMWs. At first, the two strains were separately assayed for their ability to degrade a synthetic mixture of nine aromatic acids present in OMWs, both in growing- and resting-cell conditions. Then, due to the complementary activity exhibited by the two strains, a co-culture of the two bacteria was tested under growing-cell conditions for degradation of the same synthetic mixture. Finally, the degradation activity of the co-culture on two fractions was studied. Both fractions one deriving from natural OMWs through reverse osmosis treatment and containing low-molecular weight organic molecules, and the other obtained from an anaerobic lab-scale treatment plant fed with OMWs, were rich in monocyclic aromatic compounds. The co-culture of the two strains was able to biodegrade seven of the nine components of the tested synthetic mix (2, 6-dihydroxy-benzoic acid and 3, 4, 5-trimethoxybenzoic acid were the two undegraded compounds). In addition, an efficient biodegrading activity towards several aromatic molecules present in the two natural fractions was demonstrated
Drowned or saved? Research perspectives on children’s literature in Italy
No full textCurrent literary criticism in Italy has recognised that it is still difficult to enclose children’s literature
within a category able to encompass its multifaceted characteristics (Beseghi, 2002;
Cantatore,2019). Therefore, any critical approach to its epistemological status needs to focus on
multiple points of view.
On the one hand, a diachronic method is adopted when examining literary texts and authorship. On
the other hand, it is essential to examine how young people respond to literary works, and what kind
of problems are involved in teaching reading (Lollo, 2003).
This paper aims to clarify how the epistemological study of children’s literature has been structured
in Italy in recent decades and how an epistemological statute is capable of maintaining a balance
between literary and educational considerations, today and in the past. Additionally, it aims to help
consolidate the disciplinary identity of children’s literature as distinct from other literary disciplines,
but without losing sight of its unique features and flavour (Fava, 2019).
The fact that children’s literature has no real centre of gravity may be interpreted as a flaw in the
system, an undefined component of literary and historical knowledge causing its specific
educational role for children to be overlooked. This research aims to investigate the benefits of slow
research that, in the long run, will enable the discipline to save itself instead of being drowned by
other areas of knowledg
Relationship Between Anxious Depression and Treatment Outcome in Outpatients With Depression
No full textMethod: Following a one-week, single-blind, wash-out, patients with MDD diagnosed by SCID were randomized to 12 weeks of double-blind treatment with LI 160 St. John’s wort extract (900 mg/day), fluoxetine (20 mg/day), or placebo. The 17-item Hamilton Rating Scale for Depression (HAM-D-17) was the primary efficacy measure. While anxious depression was defined as having a baseline HAM-D anxiety/somatization factor score = or > 7, remission was defined as a HAM-D-17 score = or < 7 at endpoint. The ability of both anxious depression and the individual baseline HAM-D anxiety/somatization factor scores to predict treatment outcome were assessed separately for patients treated with active treatment (St. John’s Wort or fluoxetine) and placebo with a logistic regression method.
Results: 135 patients (57% women, mean age: 37.3 ± 11.0; mean HAM-D; 19.7 ± 3.2) were randomized to double-blind treatment and were included in the intent-to-treat analyses, and the remission rates were 38% in the St. John’s wort group, 30% in the fluoxetine group, and 21% in the placebo group. After adjusting for baseline HAM-D-17 scores (minus the anxiety/somatization items), anxious depression had significantly (p < .05) lower remission rates than nonanxious depression with active treatment, but not with placebo. When the six individual items of the HAM-D anxiety/somatization facto were assessed, only psychic and somatic anxiety significantly (p < .05) predicted poorer outcome with active treatment, again after adjusting for baseline HAM-D-17 scores (minus the anxiety/somatization items).
Conclusion: The presence of anxious depression and, in particular, of psychic and somatic anxiety, significantly predicted poorer outcome following antidepressant treatment, but such relationship was not present among the placebo-treated patients.
Funding Source: Lichtwer 1. Joffe RT, Bagby RM, Levitt A: Anxious and nonanxious depression. Am J Psychiatry 150:1257–1258, 1993. 2. Fava M, Rankin MA, Wright EC, Alpert JE, Nierenberg AA, Pava J, Rosenbaum JF: Anxiety disorders in major depression. Comprehensive Psychiatry 41:97–102, 2000
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