Utilização de resíduos agroindustriais para a produção de proteases pelo termofílico Bacillus sp em fermentação submersa: otimização do meio de cultura usando a técnica de planejamento experimental

Thermophilic Bacillus sp. SMIA-2, produced protease when grown on apple pectic, whey protein and corn step liquor medium, whose concentration was varied from 3 to 10 gL-1, according to the central composite design 2³. The experiments were conducted in shaker, at 50 °C, 150 rpm and initial pH 6.5. The results revealed that the culture medium affected both, cell growth and enzyme production. After graphical and numerical optimization procedure, the enzyme production reached its maximum value at 30 h fermentation, reaching, approximately, 70 U protein mg-1, suggesting that this process was partially associated to the growth.

Validação de método para determinação de resíduos de amoxicilina aplicado à validação de limpeza em indústria farmacêutica de penicilânicos

The aim of this work was the single-laboratory validation of a quantitative method for the determination of amoxicillin residues in support of cleaning control and validation. Linearity was demonstrated between 2.5 and 17.5 μg/mL, without matrix effects. Mean recoveries ranged from 84.00 to 103.74% and the relative standard deviation under repetitivity and within-reproducibility conditions were from 0.58 to 4.20% and from 0.79 to 4.39%, respectively. The theoretical limits of detection and quantification were 0.133 and 0.442 μg/mL, respectively. The studied method was suitable for cleaning control purpose within good manufacturing practices.

Reciclagem do crômio de resíduos químicos provenientes da determinação de carbono oxidável em fertilizantes orgânicos

This work proposes a separation, recovery and reuse procedure of chemical residues with chromium. This residue was generated by the determination of oxidizable carbon in organic fertilizers samples. The Cr(VI) of the residue was reduced with ethanol and precipitated with NaOH. The Cr(OH)3 precipitate was separated and oxidized to dichromate ions with hydrogen peroxide. This solution was used another time in organic carbon determination. The uses of recycled dichromate solution were appropriated in four successive recycling. The accuracy was proven using potassium hydrogen phthalate and ten organic fertilizer samples. The organic carbon results, determined with recycled solutions, were similar the conventional solution.

Recuperação de chumbo, mercúrio e elementos dos grupos 4 a 7 da tabela periódica de seus resíduos

This work shows routes to recover some elements from their laboratory wastes and broken apparatus (thermometers and densimeters). Most elements chosen present a chemical behavior in aqueous solution which is not currently studied in the ordinary experimental classes. The routes were based on the previous knowledge of the qualitative composition of the wastes treated. Wastes containing chromium were the most difficult to treat. The elements were recovered in good yields and can be reused in new experiments. This work was a very good experience in chemistry for students and shows the need of managing wastes for a better environment.

Tratamento de resíduos de corante por eletrofloculação: um experimento para cursos de graduação em química

This paper describes the use of a simple experiment of electroflocculation for classroom in Chemistry. Parameters such as electrode material, current density and temperature direct influence the process efficiency. Due to the process low cost and efficient color removal, the methodology proposed has shown good potential for use in wastewater treatment. In addition, the proposed experiment allows discussion about environmental electrochemistry, introduction to concepts of water contamination by industry and university, and also about different alternatives in wastewater treatment used nowadays. Finally, the very easy operation make possible to easy adapt this experiment for high school and elementary school.

Caracterização cromatográfica de compostos orgânicos presentes nos resíduos sólidos provenientes de indústria de reciclagem de papel e sua aplicação na produção de briquetes de carvão vegetal

Recycling of paper in industrial scale has become an established practice worldwide. In this work, organic compositions of three different kinds of sludge generated in recycle paper industry were studied, and the incorporation of one of those sludge in briket was also investigated. The characterization of organic compounds in sludge samples and briket was performed using Gas Chromatography coupled with Mass Spectrometry after a Soxhlet extraction. Different chemical classes were identified in each type of sludge, but just the sludge composed by cellulose residue did not presented polyaromatic hydrocarbons. Four formulations of sludge incorporated with charcoal for briket production were evaluated.

Principais técnicas de preparo de amostra para a determinação de resíduos de agrotóxicos em água por cromatografia líquida com detecção por arranjo de diodos e por espectrometria de massas

The determination of pesticide residues in water samples by Liquid Chromatography require sample preparation for extraction and enrichment of the analytes with the minimization of interferences to achieve adequate detection limits. The Solid Phase Extraction (SPE), Solid Phase Microextraction (SPME), Stir Bar Sorptive Extraction (SBSE) and Dispersive Liquid-Liquid Microextraction (DLLME) techniques have been widely used for extraction of pesticides in water. In this review, the principles of these sample preparation techniques associated with the analysis by Liquid Chromatography with Diode Array Detection (LC-DAD) or Mass Spectrometry (LC-MS) are described and an overview of several applications were presented and discussed.

Degradação de corantes têxteis e remediação de resíduos de tingimento por processos Fenton, foto-Fenton e eletro-Fenton

In this work the degradation of textile dyes were evaluated, using Fenton, photo-Fenton and electro-Fenton processes. Under optimized conditions Fenton and photo-Fenton processes showed high decolorization capacity of the model dyes. The electro-Fenton process was carried out in an undivided electrochemical reactor (1000 mL) equipped with a carbon-felt cathode (253 cm²) and a platinum gauze anode (6 cm²). Under optimal conditions (J: 1.6 mA cm-2, Na2SO4: 0.075 mol L-1, pH: 3) H2O2 concentration of about 60 mg L-1 was observed. The addition of Fe2+ (15 mg L-1) induces Fenton reactions that permit almost total decolorization of textile dyes.

Implantação e implementação das normas das Boas Práticas Laboratoriais (BPL) no laboratório de análises de resíduos da Universidade Estadual de Campinas

In the context of quality and good laboratory practices, the article recovers some historical data. From a specific Institutional situation (CPQBA/UNICAMP), is presented an experience of establishing and implementing a standard (NIT-DICLA-035) for good laboratory practice according to definitions of the Brazilian authority (INMETRO) responsible for regulating, monitoring, supervising and recognition in this area. The issue aims to focus on studies of pesticide residues in GLP parameters.

UDP-N-acetilglicosamina enolpiruvil transferase: determinação dos estados de protonação de resíduos de aminoácidos do sítio ativo pelo método PM6

UDP-N-acetylglucosamine-enolpyruvyl transferase (MurA) catalyzes the reaction between phosphoenol pyruvate and UDP-N-acetylglucosamine. We present a theoretical approach using the semiempirical PM6 method for defining protonation state of three active site residues, K22, H125, and K160. Prior comparison with neutron diffraction data showed that PM6 accurately predicted protonation states of active site residues of b-trypsin and D-xylose isomerase. Using the same methodology with MurA crystallographic data, we conclude that when reaction intermediate is located at the active site, H125 and K22 are in protonated form and K160 in neutral form.

Implementação de método analítico para determinação de resíduos de organofosforados em leite por cromatografia a gás com detector fotométrico de chama

This paper regards the implementation of the QuEChERS method for the analysis by GC-FPD of 53 different pesticides from the organophosphate class, in whole UHT and pasteurized milk. Selectivity, linearity, repeatability, recovery and limits of detection and quantification were evaluated. Of all pesticide recoveries, 51 were considered satisfactory since the values ranged from 70 to 120% with RSD < 20%. The quantification limits ranged from 0.005 to 0.4 mg kg-1. The QuEChERS method was suitable for determination of 52 pesticides, presenting several advantages - quick, cheap, easy, effective, rugged and safe - with regard to other traditional methodologies.

Classificação de resíduos de madeira tratada com preservativos à base de arseniato de cobre cromatado e de boro/flúor

Classification of waste wood treated with chromated copper arsenate (CCA) and boron/fluorine preservatives, according to NBR 10004, was investigated. The leaching test (ABNT NBR 10005) for As and Cr, and solubilization test (ABNT NBR 10006) for F, were applied to out-of-service wooden poles. Concentrations of As and Cr in leachates were determined by ICP-MS and of F by ESI. Values for As were higher than 1 mg L-1 classifying the waste as hazardous material (Class I) whereas values for F (> 1.5 mg L-1) were non-hazardous but indicated non-inert material (Class IIA).

Uso de materiais recicláveis na determinação gravimétrica de CO2 no ar ambiente e tratamento dos resíduos de laboratório gerados

An alternative system was tested for the determination of CO2 in air using recyclable materials. The results indicate that the proposed system allows for reliable, accurate, robust and efficient collection, comparable to the standard gravimetric method. Laboratory wastes are easily treated using a filtrate that can be discharged into the sewer and solids that can be reused. The proposed system is a simple and low-cost tool that encompasses important aspects of environmental education, which should be part of the education in chemistry of undergraduate students and technicians.

Desenvolvimento e validação do método QuEChERS na determinação de resíduos de medicamentos veterinários em leite e carne de búfalo

Analytical methods were developed and validated to determine residues of veterinary drugs in buffalo milk and meat, using the QuEChERS method and gas chromatography-mass spectrometry. Both milk and meat, at 2 g of sample, 4 mL of acetonitrile, 0.8 g of MgSO4 and 0.2 g of NaCl, were used in the liquid-liquid partition, whereas 50 mg of C18, 50 mg of PSA and 150 mg of MgSO4 were employed in the dispersive solid-phase extraction (d-SPE). The methods showed sensitivity, precision and accuracy. The quantitation limits were in agreement with the maximum residue limit established by the Codex Alimentarius, FAO and WHO.

Resíduos de pesticidas em águas superficiais de área de nascente do Rio São Lourenço-MT: validação de método por extração em fase sólida e cromatografia líquida

A multiresidue method using HPLC/DAD for the determination of fourteen pesticides in water based on SPE, using SDVB (styrene divynilbenzene copolymer) as adsorbent was validated. Recoveries from 61 to 120%, relative standard deviation between 2 and 15% and detection limits from 0.07 to 0.75 µg L-1 were obtained. It was applied to 66 surface water samples collected in a degraded area at the headwaters of São Lourenço river, Mato Grosso, Brazil. Eight pesticides were detected in concentrations ranging from 0.15 to 35.25 µg L-1. Considering ecotoxicological data, carbendazim and carbofuran may represent a risk to aquatic organisms. These results draw attention to the contamination of this vulnerable degraded area.