Preparation and physicochemical characterization of deep eutectic solvents and ionic liquids for the potential absorption and biodegradation of styrene vapors.

Styrene emissions can be treated by physicochemical, biological, or physicochemical/biological means. Due to its low solubility in water an alternative to eliminate styrene emissions from air is the use of two-phase partitioning bioreactors (TPPBs) which comprised a hydrophobic non-aqueous phase (NAP) which can improve mass transfer of styrene. This study was devoted to prepare and evaluate the main physicochemical characteristics of novel NAPs such as Ionic liquids (ILs), Deep Eutectic Solvents (DESs) and Natural Deep Eutectic Solvents (NADEs) as well as their toxicity and biodegradability to treat styrene vapors. Absorption experiments of styrene showed that the best NAPs were the DESs formed with Tetrabutylammonium bromide and decanoic acid and the ILs [C6mim][FAP], [C4mim] [NTf2] and [C4mim] [PF6], since they presented a styrene partition coefficient between 0.0015 and 0.0041. Finally, the IL [C6mim][FAP] was used as a NAP in a TPPB batch process given its high styrene affinity, low solubility in water and non-biodegradability; styrene mineralization was three times higher in the TPPB compared with the control. ILs are potential adjuvant phases in biological degradation systems, as well as other solvents like DESs and NADESs.

Oxidative stress, inflammation and disease activity biomarkers in lupus nephropathy.

Lupus nephropathy is a severe and frequent complication of systemic lupus erythematosus. Here, we assessed the biomarkers of oxidative stress, inflammation and disease activity in patients with lupus nephritis. Thirty-four patients with active lupus nephritis, 31 patients with inactive lupus nephritis and 20 lupus patients without renal damage (non-lupus nephritis) were studied. Oxidative stress biomarkers malonyldialdehyde, oxidized-to-total glutathione, catalase, superoxide dismutase and total antioxidant status were assessed, as well as inflammation biomarkers CRP, interleukin 6 and monocyte chemoattractant protein 1. Renal tubular disease biomarkers neutrophil gelatinase-associated lipocalin and ß2-microglobulin were assessed, together with the classic disease activity biomarkers urinary protein/creatinine ratio, anti-dsDNA, anti-C1q antibody and complement proteins C3 and C4. Significant differences were found between active lupus nephritis and inactive lupus nephritis patients and between active lupus nephritis and non-lupus nephritis patients for all the assessed biomarkers (P < 0.05), except for catalase, superoxide dismutase and interleukin 6. There is an imbalance in the redox status in active lupus nephritis patients that would be involved in lipid peroxidation of the glomerular basal membrane that would alter its integrity and could also affect renal tubular function in these patients.

Biofiltration of high formaldehyde loads with ozone additions in long-term operation.

Formaldehyde (FA) biofiltration was evaluated over 310 days with and without ozone addition. Without ozone, the biofilter was able to treat formaldehyde at inlet loads (ILs) lower than 40 g m(-3) h(-1), maintaining, under this condition, an average removal efficiency (RE) of 88 % for a few days before collapsing to zero. The continuous addition of ozone (90 ppbv) helped to recover the RE from zero to 98 ± 2 % and made it possible to operate at an IL of 40 g m(-3) h(-1) for long periods of operation (107 days). Furthermore, the ozone addition aided in operating the biofilter at a formaldehyde IL of up to 120 g m(-3) h(-1) values that have never before been reached. GC-mass spectrometry (MS) analysis showed that dimethoxymethane was the common compound in leachate during the performance decay. Also, the addition of ozone aided in maintaining an optimal pH in the biofilter with values between 7.5 and 8.2, due to the carbonate species formed during the ozone reactions with formaldehyde and its by-products. Thus, the pH control was confirmed and the alkalinity of the biofilter increased from 334.1 ± 100.3 to 1450 ± 127 mg CaCO3 L(-1) when ozone was added. Ozone addition diminished the exopolymeric substances (EPS) content of biofilm and biofilm thickness without affecting cell viability. Kinetic parameters suggested that the best conditions for carrying out FA biofiltration were reached under ozone addition. The addition of ozone during formaldehyde biofiltration could be a good strategy to maintain the pH and the steady state of the system under high ILs and for long periods of operation.

Biosynthesis and characterization of polyhydroxyalkanoates produced by an extreme halophilic bacterium, Halomonas nitroreducens, isolated from hypersaline ponds.

AIMS: Morphological, biochemical and genotypic characterization of a halophilic bacterium isolated from hypersaline ponds located at Las Coloradas (Río Lagartos, Yucatán, Mexico). Characterization of polymer produced by this strain was also performed. METHODS AND RESULTS: Twenty strains were isolated from water samples of salt ponds and selected based on both morphological features and their PHA storage capacity, which were determined by SEM and staining methods with Nile red and Nile blue, respectively; strains were also analysed by the fluorescence imaging technique. Among them, JCCOL25.8 strain showed the highest production of PHA's reason why phenotypic and genotypic characterization was performed; this strain was identified as Halomonas nitroreducens. Polymer produced by this strain was characterized by FTIR, DSC, GPC and EDX spectroscopy. Results indicated that the biosynthesized polymer was polyhydroxybutyrate (PHB) which had a melting peak at 170°C and a crystallinity percentage of about 36%. CONCLUSIONS: Based on phenotypic and genotypic aspects, JCCOL25.8 strain was identified as H. nitroreducens and it was capable to accumulate PHB. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, there is only one study published on the biosynthesis of PHA's by H. nitroreducens strains, although the characterization of the obtained polymer was not reported.

Hexane abatement and spore emission control in a fungal biofilter-photoreactor hybrid unit.

The performance of a fungal perlite-based biofilter coupled to a post-treatment photoreactor was evaluated over 234 days in terms of n-hexane removal, emission and deactivation of fungal spores. The biofilter and photoreactor were operated at gas residence times of 1.20 and 0.14min, respectively, and a hexane loading rate of 115±5gm(-3)h(-1). Steady n-hexane elimination capacities of 30-40gm(-3)h(-1) were achieved, concomitantly with pollutant mineralization efficiencies of 60-90%. No significant influence of biofilter irrigation frequency or irrigation nitrogen concentration on hexane abatement was recorded. Photolysis did not support an efficient hexane post-treatment likely due to the short EBRT applied in the photoreactor, while overall hexane removal and mineralization enhancements of 25% were recorded when the irradiated photoreactor was packed with ZnO-impregnated perlite. However, a rapid catalyst deactivation was observed, which required a periodic reactivation every 48h. Biofilter irrigation every 3 days supported fungal spore emissions at concentrations ranging from 2.4×10(3) to 9.0×10(4)CFUm(-3). Finally, spore deactivation efficiencies of ≈98% were recorded for the photolytic and photocatalytic post-treatment processes. This study confirmed the potential of photo-assisted post-treatment processes to mitigate the emission of hazardous fungal spores and boost the abatement performance of biotechnologies.

Enhancing ethylbenzene vapors degradation in a hybrid system based on photocatalytic oxidation UV/TiO2-In and a biofiltration process.

The use of hybrid processes for the continuous degradation of ethylbenzene (EB) vapors has been evaluated. The hybrid system consists of an UV/TiO(2)-In photooxidation coupled with a biofiltration process. Both the photocatalytic system using P25-Degussa or indium-doped TiO(2) catalysts and the photolytic process were performed at UV-wavelengths of 254 nm and 365 nm. The experiments were carried out in an annular plug flow photoreactor packed with granular perlite previously impregnated with the catalysts, and in a glass biofilter packed with perlite and inoculated with a microbial consortium. Both reactors were operated at an inlet loading rate of 127 g m(-3)h(-1). The greatest degradation rate of EB (0.414 ng m(-2)min(-1)) was obtained with the TiO(2)-In 1%/365 nm photocatalytic system. The elimination capacity (EC) obtained in the control biofilter had values ≈ 60 g m(-3)h(-1). Consequently, the coupled system was operated for 15 days, and a maximal EC of 275 g m(-3)h(-1). Thus, the results indicate that the use of hybrid processes enhanced the EB vapor degradation and that this could be a promising technology for the abatement of recalcitrant volatile organic compounds.

Performance of innovative PU-foam and natural fiber-based composites for the biofiltration of a mixture of volatile organic compounds by a fungal biofilm.

The performance of perlite and two innovative carriers that consist of polyurethane (PU) chemically modified with starch; and polypropylene reinforced with agave fibers was evaluated in the biofiltration of a mixture of VOCs composed of hexane, toluene and methyl-ethyl-ketone. At a total organic loading rate of 145 gCm(-3)h(-1) the elimination capacities (ECs) obtained were 145, 24 and 96 gCm(-3)h(-1) for the biofilters packed with the PU, the reinforced polypropylene, and perlite, respectively. Specific maximum biodegradation rates of the mixture, in the biofilters, were 416 mgCg(protein)(-1) h(-1) for the PU and 63 mgCg(protein)(-1) h(-1) for perlite, which confirms the highest performance of the PU-composite. 18S rDNA analysis from the PU-biofilter revealed the presence of Fusarium solani in its sexual and asexual states, respectively. The modified PU carrier significantly reduced the start-up period of the biofilter and enhanced the EC of the VOCs. Thus, this study gives new alternatives in the field of packing materials synthesis, promoting the addition of easily biodegradable sources to enhance the performance of biofilters.

Effect of surfactant and oil additions in the biodegradation of hexane and toluene vapours in batch tests.

The biological treatment of gaseous emissions of hydrophobic volatile organic compounds (VOCs) results in low rates of elimination partially because of the low solubility of VOCs in water. Recently, the use of two-phase partition bioreactors (TPPBs) was proposed to increase the bioavailability and consequently the elimination capacities of this kind of VOC. In the present study, TPPBs operating in a batch feed mode were tested for biodegradation of hexane and toluene vapours with a microbial consortium. The results obtained were compared with single-phase systems (control experiments). The liquid phase used was silicone oil (organic phase) with the surfactant Pluronic F-68. Experiments were named F1 and F2 for one and two phases, respectively, and F(1S) and F(2S) when the surfactant was included. The maximum specific rates (S(rates)) of hydrocarbon consumption for hexane and toluene were 539 and 773 mg(hydrocarbon)/(g(protein) x h), respectively. For both substrates, the systems that showed the highest S(rates) of hydrocarbon consumption were F2 and F(2S). In experiment F(1S) the surfactant Pluronic F-68 increased the solubility of hydrocarbons in the liquid phase, but did not increase the S(rates). The maximum percentages of mineralization were 51% and 72% for hexane and toluene, respectively. The results showed that simultaneous addition of silicone oil and surfactant favours the mineralization, but not the rate ofbiodegradation, of toluene and hexane vapours.

Onset and evolution of nephropathy in rats with spontaneous diabetes mellitus.

The occurrence of renal diabetic complications was studied in diabetic nonobese IIM/FmeSS (eSS) rats. The results were compared with eumetabolic Wistar rats paired by sex and age. Between 6 and 12 months of age, eSS male rats had higher fructosamine values and glucose intolerance as well as increasing proteinuria and uremia. Enhancement in water, calcium and phosphorus fractional excretion with a concomitant lower sodium excretion, was observed from 12 months of age on. 18- and 21-month-old eSS rats exhibited fasting hyperglycaemia and rising values of fructosamine, glucose intolerance and glycosuria. Simultaneously, a notorious worsening of proteinuria as well as alterations in glomerular filtration were verified. Optic microscopy of 12-month-old eSS rat kidneys showed areas of tubular dilatation with protein cylinders. In 21-month-old eSS animals, kidneys appeared overtly damaged. Increased capsular, glomerular and Henle's thin loop diameters were verified in 12- and 21-month-old eSS rats. Glomeruli showed diffuse hypertrophy of mesangial tissue and thickening of the basement membrane. Areas of markedly atrophic and dilated tubules containing acidophilic proteinaceous material were observed. At age of 21 months, kidneys of eumetabolic Wistar control rats presented foci of interstitial and pielic inflammatory infiltrates.

Inhibitory effect of bilirubin on complement-mediated hemolysis.

We investigated the in vitro action of the bile pigments, unconjugated bilirubin (UB) and bilirubin monoglucuronide (BMG) on complement (C) cascade reaction. Both UB and BMG inhibited hemolysis in the classical pathway (CP) in a dose-dependent manner at low micromolar concentrations, UB showing a stronger effect than BMG. The analysis of the action of UB on the hemolytic activity of the C1, C4, C2 and C-EDTA components of the C cascade revealed that the C1 step was the most inhibited. An enzyme immunoassay was developed to evaluate the effect of UB on the binding of C1q, one of the subcomponents of C1, to human IgM and IgG. The study demonstrated that the unconjugated pigment interferes both the C1q-IgM and -IgG interactions, thus tentatively explaining the inhibitory action of UB on hemolytic activity of C1. We conclude that the anti-complement effect of UB is mainly exerted on the C1 component, the recognition unit of CP. The potential clinical implication of the reported effects in hyperbilirubinemia is discussed.

Neonatal tetanus mortality in Veracruz, Mexico, 1989.

This article describes a survey conducted in the State of Veracruz, Mexico, to estimate neonatal tetanus (NNT) mortality. The survey, which entailed visits to 72,720 households, collected data on 8,401 live births and 209 infant deaths occurring between April 1988 and May 1989. Twenty-six of the 209 fatalities conformed to a WHO standard case definition of death from neonatal tetanus. The estimated neonatal tetanus mortality was thus 3.1 deaths per 1,000 live births (95% confidence limits = 1.7, 4.5). Comparison of this rate to reported figures suggests that for every NNT death recorded in Veracruz during the study period, as many as 50 others went unreported. A case-control study nested within the survey was conducted to assess preventable NNT risk factors. Limited information on 13 NNT deaths and 217 controls showed an increased risk for neonates who were delivered at home and whose parents' ethnic background was Mexican Indian. Five of the 13 fatalities had their umbilical cords cut with a domestic or traditional cutting tool such as a reed cane, as compared to none of the 217 controls. The observed vaccine efficacy of 2+ doses of tetanus toxoid was 70% (95% confidence limits = 52, 100). Both the mothers of neonates who died of NNT and their controls missed an average of five opportunities to receive tetanus toxoid. These findings underscore the need to launch a perinatal health program serving Mexico's high-risk populations.