Colorimetric detection of Pseudomonas aeruginosa by aptamer-functionalized gold nanoparticles.

Novel rapid methodologies for the detection of bacteria have been recently investigated and applied. In hospital environments, infections by pathogens are very common and can cause serious health problems. Pseudomonas aeruginosa is one of the most common bacteria, which can grow in hospital equipment such as catheters and respirators. Even at low concentrations, it can cause severe infections as it is resistant to antibiotics and other treatments. Based on this subject's relevance, this work aimed to develop a colorimetric biosensor using aptamer-functionalized gold nanoparticles for identifying P. aeruginosa. The detection mechanism is based on the color change of gold nanoparticles (AuNPs) from red to blue-purple through NaCl induction after bacteria incubation and aptamer-target binding. First, AuNPs were synthesized and characterized. The influence of aptamer and sodium chloride concentration on the agglomeration of AuNPs was investigated. Optimization of aptamer concentration and salt addition were performed. The best condition for detection was 5 µM aptamers and 200 mM of NaCl. In this case, P. aeruginosa was detected after 5 h for concentrations from 108 to 105 CFU mL-1, being 105 and 104 CFU mL-1 the detection limit for color change by the naked eye and UV-Vis spectrometry, respectively. In addition, other bacteria such as E. coli, S. typhimurium, and Enterobacteriaceae bacterium were also detected with color changing from red to gray. Finally, it was confirmed that the salt incubation time can be 2 h, and that the ideal aptamer concentration is 5 µM. Thus, the colorimetric analysis can be a simple and fast detection method for P. aeruginosa in the range of 108 to 105 CFU mL-1 to the naked eye. KEY POINTS: • A new method for rapid detection of Pseudomonas aeruginosa • Aptamers conjugated with gold nanoparticles allow pathogen detection by colorimetry • No need for previous surface modification of nanoparticles.

Production of new nanobiocatalysts via immobilization of lipase B from C. antarctica on polyurethane nanosupports for application on food and pharmaceutical industries.

Nanobiocatalysts were produced via immobilization of CalB lipase on polyurethane (PU) based nanoparticles and their application on the synthesis of important industrial products was evaluated. Nanoparticles of polyurethane functionalized with poly(ethylene glycol) (PU-PEG) were synthetized through miniemulsion polymerization and the addition of crosslinking agents were evaluated. The nanoparticles were employed as support for CalB and the kinetic parameters were reported. The performance of new biocatalysts was evaluated on the hydrolysis reaction of p-NPB and on the enantioselective hydrolysis of (R,S)-mandelic acid. The esterification reaction was evaluated on the production of ethyl esters of Omega-3. The effect of poly(ethylene glycol) molar mass (400, 4000 or 6000 Da)on the biocatalyst activity was also analyzed. The PU-PEG6000-CalB showed the highest value of the kinetic parameters, highlighting the high reaction rate. The addition of trehalose as crosslinking agent improved the thermal stability of the biocatalysts. PU-PEG400-CalB was the most active nanobiocatalyst, exhibiting a ethyl esters production of 43.72 and 16.83 mM.U -1 using EPA and DHA, respectively. The nanobiocatalyst was also applied in enantiomeric resolution of mandelic acid, showing promising enantiomeric ratios. The results obtained in this work present alternative and sustainable routes for the synthesis of important compounds used on food and pharmaceutical industries.

Pre-treatment Strategies for Value Addition in Poultry Litter.

We studied different pre-treatments of poultry litter aiming to add economic value to this residue. Strategies were applied to extract ammonium nitrogen with the aim of allowing its further use as fertilizer, and to promote the hydrolysis and solubilization of lignocellulosic components with the aim of facilitating its subsequent conversion to biogas. Ammonia extraction was performed by solubilization in water in a one-step process and by successive extraction steps (3 times 60 min). Successive extractions presented greater removal of total ammonia nitrogen than did one-step extraction, solubilizing about 36% of the ammonia in water. In parallel pre-treatment using ultrasound was performed to increase carbon bioavailability for anaerobic digestion. Using this tool, 24.7 g kg-1 of total organic carbon and 13.0 g kg-1 of total reducing sugars were solubilized, employing 10% dry mass sample amount, 100% amplitude ultrasound at frequency of 20 kHz amplitude and 2.5 min of treatment (energy input of 299 ± 7 kJ L-1; 3,822 ± 95 kJ kg-1). Anaerobic digestion of ultrassound pre-treated biomass was evaluated using a biological biogas production assay, and an increase of 10% of biogas production was obtained compared to untreated samples (147.9 and 163.0 mL g-1 for crude and pre-treated PL, respectively). The findings suggest that these are environmentally friendly and sustainable strategies to add economic value to poultry litter, reducing the environmental impacts of improper disposal.

An overview and future prospects on aptamers for food safety.

INTRODUCTION: Many bacteria are responsible for infections in humans and plants, being found in vegetables, water, and medical devices. Most bacterial detection methods are time-consuming and take days to give the result. Aptamers are a promising alternative for a quick and reliable measurement technique to detect bacteria present in food products. Selected aptamers are DNA or RNA oligonucleotides that can bind with bacteria or other molecules with affinity and specificity for the target cells by the SELEX or cell-SELEX technique. This method is based on some rounds to remove the non-ligand oligonucleotides, leaving the aptamers specific to bind to the selected bacteria. Compared with conventional methodologies, the detection approach using aptamers is a rapid, low-cost form of analysis. OBJECTIVE: This review summarizes obtention methods and applications of aptamers in the food industry and biotechnology. Besides, different techniques with aptamers are presented, which enable more effective target detection. CONCLUSION: Applications of aptamers as biosensors, or the association of aptamers with nanomaterials, may be employed in analyses by colorimetric, fluorescence, or electrical devices. Additionally, more efficient ways of sample preparation are presented, which can support food safety to provide human health, with a low-cost method for contaminant detection. Key points • Aptamers are promising for detecting contaminants outbreaks. • Studies are needed to identify aptamers for different targets.

Are TiO2 nanoparticles safe for photocatalysis in aqueous media?

Although environmental and toxicity concerns are inherently linked, catalysis using photoactive nanoparticles and their hazardous potential are usually addressed independently. A toxicological assessment under the application framework is particularly important, given the pristine nanoparticles tend to change characteristics during several processes used to incorporate them into products. Herein, an efficient TiO2-functionalized macroporous structure was developed using widely adopted immobilization procedures. The relationships between photocatalysis, catalyst release and associated potential environmental hazards were assessed using zebrafish embryonic development as a proxy. Immobilized nanoparticles demonstrated the safest approach to the environment, as the process eliminates remnant additives while preventing the release of nanoparticles. However, as acute sublethal effects were recorded in zebrafish embryos at different stages of development, a completely safe release of TiO2 nanoparticles into the aquatic environment cannot be advocated.

Adsorption of natural annatto dye by kaolin: kinetic and equilibrium.

The adsorption of annatto dye was analysed using kaolin clay as the adsorbent. In this work, the influence of the adsorbent particle size, agitation (0 and 100 rpm), temperature (25, 40, and 60°C), and salt presence (sodium chloride and sodium sulphate at 1, 2 and 3 wt%) on the adsorption process was studied. The adsorption increased 14.21% for particles smaller than 45 µm and the agitation (100 rpm) led to an increase of 22.41% compared to the system without agitation. The ΔG° (237.711 kJmol-1) indicated that the adsorption process was spontaneous. The negative value of ΔS° (-408.999 Jmol-1K-1) and ΔH° (-115.829 kJmol-1) showed an exothermic physisorption process. The adsorption kinetics follows the pseudo-second-order model. In the adsorption equilibrium, the tested models provided good correlation coefficients ranging from 0.744 to 0.999 with the best fit observed for the Langmuir model. The maximum adsorption capacity of the kaolin clay for the annatto dye was obtained at 25°C with 1% of sodium sulphate (q max = 59.88 mgg-1).

Integração do Canto Mãe Coruja de Garanhuns com a Unidade de Saúde da Família da Liberdade / Integration of the Canto Mãe Coruja de Garanhuns with the Liberdade Family Health

O Programa Mãe Coruja Pernambucana foi criado em 2007, mais só em 2009 que ele chegou na V Região de Saúde onde Garanhuns faz parte. O Programa tem como objetivo reduzir a mortalidade materna e infantil. Integra 11 secretarias estaduais. Tem como objetivo também garantir uma qualidade no pré-natal e no puerpério às mulheres e as crianças o direito a um nascimento e desenvolvimento saudável. Fortalecer o vínculo afetivo entre mãe, filho e família. A função dos técnicos é monitorar, visualizar necessidades e encaminhar. A parceria com o município é essencial para o funcionamento do Programa. Diante dos riscos e a vulnerabilidade existentes em grávidas como também das crianças de zero a cinco anos, a prestação de um serviço de atenção à saúde eficaz para assegurar que a gravidez transcorra sem irregularidades, sem comprometimento com a saúde em todos os aspectos, tanto da mulher e consequentemente da criança. É necessário um pré-natal com boa qualidade além de oferecer segurança, tornando essa gestação saudável e mais segura podendo identificar precocemente possíveis riscos para morbidade materno-infantil. Este projeto de intervenção busca tornar o Programa Mãe coruja de Garanhuns um indutor e parceiro dentro do município. Principalmente junto a Atenção Básica, incentivar as equipes das unidades básicas de saúde para informar a população sobre o programa, sua importância no cuidado e acompanhamento das gestantes e crianças. Pois os benefícios realizados pelo Programa Mãe Coruja como política pública vem apresentando redução acentuada quanto a morbidade materno-infantil.(AU)

The Mãe Coruja Pernambucana Program was created in 2007, but it was only in 2009 that it arrived in the V Health Region where Garanhuns is part. The Program aims to reduce maternal and infant mortality. Integrates 11 state secretariats. It also aims to ensure quality prenatal care and postpartum care for women and children the right to a healthy birth and development. Strengthen the affective bond between mother, child and family. The function of technicians is to monitor, visualize needs and forward. The partnership with the municipality is essential for the Program to function. Faced with the risks and vulnerability that exist in pregnant women as well as in children from zero to five years old, the provision of an effective health care service to ensure that the pregnancy takes place without irregularities, without compromising health in all aspects, both woman and consequently the child. Good quality prenatal care is necessary, in addition to offering safety, making this pregnancy healthier and safer, being able to identify early possible risks for maternal and child morbidity. This intervention project seeks to make the Mother Owl of Garanhuns Program an inducer and partner within the municipality. Mainly with Primary Care, encourage teams from basic health units to inform the population about the program, its importance in the care and monitoring of pregnant women and children. Because the benefits realized by the Mãe Coruja Program as a public policy have been showing a marked reduction in terms of maternal and child morbidity.(AU)

New sustainable alternatives to reduce the production costs for surfactin 50 years after the discovery.

In 1968, Arima et al. discovered the heptapeptide, known as surfactin, which belongs to a family of lipopeptides. Known for its ability to reduce surface tension, it also has biological activities such as antimicrobial and antiviral. Its non-ribosomal synthesis mechanism was later discovered (1991). Lipopeptides represent an important class of surfactants, which can be applied in many industrial sectors such as food, pharmaceutical, agrochemicals, detergents, and cleaning products. Currently, 75% of the surfactants used in the various industrial sectors are from the petrochemical industry. Nevertheless, there are global current demands (green chemistry concept) to replace the petrochemical products with environmentally friendly products, such as surfactants by biosurfactants. The production biosurfactants still are costly. Thus, an alternative to reduce the production costs is using agro-industrial waste as a culture medium associated with an efficient and scalable purification process. This review puts a light on the agro-industrial residues used to produce surfactin and the techniques used for its recovery.

Removal of chromium from wastewater by swine hair residues applied as a putative biofilter.

Swine production chain generates residues with potential application in environmental processes. This study aimed at the use of swine hair as a potential biofilter for hexavalent chromium (Cr(VI)) removal from wastewater of tannery industry. The hair was pretreated using H2O2 in alkaline medium, and statistical analysis was carried out to evaluate the hair degradation, as well the Cr(VI) removal by the potential pretreated biofilter. The results showed 99% of Cr(VI) removal in 105 min of treatment in large pH range (1-10). Treated and untreated effluents were submitted to cytotoxicity study using vegetable and animal cells, demonstrating a significant reduction on toxicity to both cells. Therefore, swine hair demonstrated to be a promising residue for heavy metal removal on the perspective of an environmentally friendly technique.

Harsh environment resistant - antibacterial zinc oxide/Polyetherimide electrospun composite scaffolds.

Strategies for developing materials with the functionality to combat bacterial infection are targets for applications such as smart bandages and bone tissue integration. This work milestone was to develop ZnO-polyetherimide (ZnO/PEI) composite scaffolds with antibacterial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The electrospinning process using suspensions of PEI with different ZnO nanoparticles content were heightened to promote spinnability, jet stability, and fibers with morphological homogeneity. Simulating harsh environments (laser ablation and solvent corrosion) was employed onto specimens and antibacterial functionality, morphology variations, contact angle, and tensile strength variability were evaluated. The antibacterial outcomes, accessed by a modified version of the Japanese Industrial Standard (JIS) Z 2801, presented an inhibition rate up to 100 and 99% after 24 h for S. aureus and E. coli, respectively. The treated samples presented alike responses against both bacteria, highlighting the robustness of the developed scaffolds.

Diethyldithiocarbamate loaded in beeswax-copaiba oil nanoparticles obtained by solventless double emulsion technique promote promastigote death in vitro.

Leishmaniasis is considered a neglected tropical disease that represents a Public Health problem due to its high incidence. In the search of new alternatives for Leishmaniasis treatment diethyldithiocarbamate (DETC) has shown an excellent leishmanicidal activity and the incorporation into drug carrier systems, such as solid lipid nanoparticles (SLNs), is very promising. In the present work DETC loaded in beeswax nanoparticles containing copaiba oil were obtained by the double emulsion/melt technique. The nanoparticles were characterized and leishmanicidal activity against L. amazonensis promastigotes forms and cytotoxicity in murine macrophages were evaluated. SLNs presented size below 200 nm, spherical morphology, negative charge surface, high encapsulation efficiency, above 80%, and excellent stability. Moreover, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analyses were performed to evaluate the chemical structure and possible interactions between DETC and SLNs. SLNs provided a protection for DETC, decreasing its cytotoxic effects in macrophages, which led to an improvement in the selectivity against the parasites, which almost doubled from free DETC (11.4) to DETC incorporated in SLNs (18.2). These results demonstrated that SLNs had a direct effect on L. amazonensis promastigotes without affect the viability of macrophage cell, can be a promising alternative therapy for the cutaneous treatment of L. amazonensis.

Effect of magnetic field on the Eversa® Transform 2.0 enzyme: Enzymatic activity and structural conformation.

Alternatives to improve the stability and activity of enzymes have been rising in the last years due to the potential industrial application of these catalysts. However, the enzymes characteristics in terms of stability and catalytic efficiency can reduce, in some cases, due to the reaction conditions. Due to a lack in the literature concerning structural information related to the new commercial Eversa® Transform 2.0 enzyme (NS-40116) we investigated the conformational structure by spectroscopic and mass spectrometry techniques after exposure in permanent magnetic flux density (0.7 and 1.34 T) in recirculation mode (1, 2, and 4 h) at 0.06 L·min-1. The influence of pH on the enzymatic solution associated with the magnetic flux (pH 5, 7, and 9) was also evaluated. Under the best reaction condition (pH 7 after 4 h in a recirculation mode at 1.34 T), enzyme activity 77% higher than the control sample was obtained. Mass spectrometry techniques showed changes in the NS-40116 tertiary structure. Thus, the application of magnetic fields as an enzymatic pre-treatment showed to be a promising technique and a viable alternative to increase the enzymatic activity since it is a low cost, environmentally friendly, and ease operation process.

Synthesis of a green polyurethane foam from a biopolyol obtained by enzymatic glycerolysis and its use for immobilization of lipase NS-40116.

The use of green sources for materials synthesis has gained popularity in recent years. This work investigated the immobilization of lipase NS-40116 (Thermomyces lanuginosus lipase) in polyurethane foam (PUF) using a biopolyol obtained through the enzymatic glycerolysis between castor oil and glycerol, catalyzed by the commercial lipase Novozym 435 for the PUF formation. The reaction was performed to obtain biopolyol resulting in the conversion of 64% in mono- and diacylglycerol, promoting the efficient use of the reaction product as biopolyol to obtain polyurethane foam. The enzymatic derivative with immobilized lipase NS-40116 presented apparent density of 0.19 ± 0.03 g/cm3 and an immobilization yield was 94 ± 4%. Free and immobilized lipase NS-40116 were characterized in different solvents (methanol, ethanol, and propanol), temperatures (20, 40, 60 and 80 °C), pH (3, 5, 7, 9 and 11) and presence of ions Na+, Mg++, and Ca++. The support provided higher stability to the enzyme, mainly when subjected to acid pH (free lipase lost 80% of relative activity after 360 h of contact, when the enzymatic derivative lost around 22%) and high-temperature free lipase lost 50% of relative activity, while the immobilized remained 95%. The enzymatic derivative was also used for esterification reactions and conversions around 66% in fatty acid methyl esters, using abdominal chicken fat as feedstock, were obtained in the first use, maintaining this high conversion until the fourth reuse, proving that the support obtained using environmentally friendly techniques is applicable.

Toxicity of enzymatically decolored textile dyes solution by horseradish peroxidase.

The oxidative systems including enzymatic systems have been widely studied as an alternative for textile effluents treatment. However, studies have shown that some oxidative processes can produce degradation products with higher toxicity than the untreated dye. In this work, enzymatic dye decolorization was evaluated by horseradish peroxidase enzyme (HRP) and the toxicity of discoloration products was evaluate against Daphnia magna, Euglena gracilis algae, and Vibrio fischeri. Dye decolorization kinetics data were evaluated and the pseudo-second-order model showed the best-fitting to the experimental data. In addition, it was observed an increased acute and chronic toxicity associated with the decolorization efficiency. The Reactive Blue 19 and Reactive Black dye showed the highest toxicity against D. Magna (16 toxicity factor) and V. Fischeri (32 toxicity factor) after enzymatic decolorization. For the chronic toxicity against D. Magna, Reactive Red was the only dye with no fertility inhibition. In relation to toxicity tests with E. gracilis algae, it was not observed photosynthetic inhibition for all dyes. This study verified the viability of the enzyme horseradish peroxidase in the textile dyes decolorization and the importance to evaluate the decolorization products.

Second-generation ethanol from non-detoxified sugarcane hydrolysate by a rotting wood isolated yeast strain.

This work aims to evaluate the production of second-generation ethanol from sugarcane bagasse hydrolysate without acetic acid (inhibitor) detoxification. Three isolated yeast strains from lignocellulosic materials were evaluated, and one strain (UFFS-CE-3.1.2), identified using large subunit rDNA sequences as Wickerhamomyces sp., showed satisfactory results in terms of ethanol production without acetic acid removal. A Plackett-Burman design was used to evaluate the influence of hydrolysate composition and nutrients supplementation in the fermentation medium for the second-generation ethanol production. Two fermentation kinetics were performed, with controlled pH at 5.5, or keeping the initial pH at 4.88. The fermentation conducted without pH adjustment and supplementation of nutrients reported the best result in terms of second-generation ethanol production. Wickerhamomyces sp., isolated as UFFS-CE-3.1.2, was considered promising in the production of second-generation ethanol by using crude (non-detoxified) sugarcane hydrolysate.

Comparison of macauba and soybean oils as substrates for the enzymatic biodiesel production in ultrasound-assisted system.

The objective of this study is to evaluate the batch enzymatic production of biodiesel in solvent-free system under ultrasound using as substrates ethanol, soybean oil and macauba fruit oil. For this purpose, a Plackett & Burman experimental design was carried out for soybean oil while a 24-1 design was conducted for macauba oil in order to maximize the biodiesel conversion for each system. Good conversions to fatty acid ethyl esters (FAEE), 88% for soybean oil and 75.2% for macauba oil, was obtained thus demonstrating the potential use of ultrasound for this reaction system.

Enzymatic synthesis of ascorbyl ester derived from linoleic acid.

Antioxidants are substances that defend cells against damage, kidnapping and destroying free radicals. They have been largely used in the food industry due the possibility to control the oxidation process, aimed to increase shelf life. Thus, esterification reaction to obtain ascorbyl linoleate catalyzed by Novozym 435 lipase assisted by ultrasound bath was investigated. In this work, molecular sieve (4 Å) was added to the reaction medium to remove the water formed during the esterification reaction to improve the process performance. According to the results, ascorbyl linoleate production up to 90 % was reached after 1 h of reaction time carried out using ultrasound bath, 1:9 molar ratio of substrates L-ascorbic acid to linoleic acid, 20 mL of tert-butanol as organic solvent, 5 wt% of Novozym 435 lipase, 10 wt% of molecular sieve at 70 °C.

Immobilization of Candida antarctica Lipase B on Magnetic Poly(Urea-Urethane) Nanoparticles.

Poly(urea-urethane) (PUU) nanoparticles with encapsulated superparamagnetic magnetite (Fe3O4) were obtained by interfacial miniemulsion polymerization and used as support for immobilization of lipase B from Candida antarctica (CALB). CALB enzyme was immobilized on magnetic PUU nanoparticles in two steps. The enzyme was immobilized in the lyophilized nanoparticles (magnetic PUU) after the support synthesis in phosphate buffer (pH 7.6) containing CALB, by the contact between nanoparticles and enzymatic solution. The mixture was incubated at 30 °C in an orbital shaker during 0.5 until 6 h to determine the time for maximum immobilization efficiency. The enzyme activity was determined by esterification reactions between lauric acid and propanol. Residual activities above 95 % in relation to free enzyme were obtained in 1 h of immobilization with enzyme concentration of 0.55 mg/mL. FTIR spectrum and SEM-FEG images were used to confirm the presence of CALB on magnetic support after immobilization and stability of support even after immobilization process, respectively. Thermal (40, 60, and 80 °C) and pH (pH 4, 7, and 10) stabilities, storage stability, and reuse were evaluated. CALB immobilized derivatives showed high stabilities with residual activities of 95, 100, and 100 % at 40, 60, and 80 °C, respectively, in 6 h of incubation. After incubation in different pH values, CALB immobilized derivative presented activities of 81, 76, and 69 % in relation to activities in the beginning of the stabilization process in pH 4, 7, and 10, respectively. Furthermore, CALB immobilized derivative reduces only 15 % of its activity after 30 days of storage at 4 °C. Reuse results showed that immobilized CALB on magnetic PUU nanoparticles led to 95 % of geranyl oleate conversion after 8 cycles of application demonstrating high stability of the CALB immobilized derivative under different conditions.

Synthesis of PEG-PCL-based polyurethane nanoparticles by miniemulsion polymerization.

In this work biocompatible polyurethane nanoparticles for future application as noninvasive polymeric nanocarriers using propellant-based inhalers in the treatment of respiratory diseases were prepared by miniemulsion interfacial polymerization derived from isophorone diisocyanate, poly(ϵ-caprolactone), and poly(ethylene glycol). The effects of the surfactant type, nonionic Tween 80 and Brij 35, anionic sodium dodecyl sulfate, and cationic cetyltrimethyl ammonium bromide, and poly(ethylene glycol) molar mass on the stability, size and morphology of nanoparticles were evaluated. In addition, the ability of cells to proliferate in contact with polyurethane nanoparticles was assessed by MTS ([(3-(4,5-dimethylthiazole-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfo-phenyl)-2H-tetrazolium, inner salt]) assay using human lung adenocarcinoma A549 cells, an in vitro model of Type II alveolar epithelium.

Evaluation of different methods for immobilization of Candida antarctica lipase B (CalB lipase) in polyurethane foam and its application in the production of geranyl propionate.

With the aim of studying the best method for the interaction of polyurethane (PU) foam and Candida antarctica lipase B, different methods of CalB immobilization were studied: adsorption (PU-ADS), bond (using polyethyleneimine) (PU-PEI), ionic adsorption by PEI with cross-linking with glutaraldehyde (PU-PEI-GA) and entrapment (PU). The characterization of immobilized enzyme derivatives was performed by apparent density and Fourier transform infrared spectroscopy. The free enzyme and enzyme preparations were evaluated at different pH values and temperatures. The highest enzyme activity was obtained using the PU method (5.52 U/g). The methods that stood out to compare the stabilities and kinetic parameters were the PU and PU-ADS. Conversions of 83.5 and 95.9 % for PU and PU-ADS derivatives were obtained, in 24 h reaction, using citronella oil and propionic acid as substrates.