a. Sara Mesquita, 2270, 60511-110 Fortaleza -CE, Brasil Recebido em 16/10/06; aceito em 25/5/07; publicado na web em 9/11/07 COMPARATIVE PERFORMANCE OF Candida rugosa LIPASE IMMOBILIZED ON POLYSILOXANE POLYVINYL ALCOHOL HYBRID SUPPORT USING DIFFERENT METHODOLOGIES. The efficiency for immobilizing microbial Candida rugosa lipase on a hybrid matrix of polysiloxane polyvinyl alcohol, by adsorption, covalent coupling and encapsulation was compared. The activities of immobilized derivatives were evaluated using p-nitrophenylpalmitate (hydrolysis) and butyric acid and butanol (esterification) as substrates. Operational stability and storage tests were also performed. Among the procedures tested, the proposed matrix was efficient for immobilizing C. rugosa lipase by adsorption and covalent coupling techniques and unsuitable for encapsulation purposes. The results reveal that better catalytic properties in both aqueous and organic media were demonstrated by the covalent coupling POS-PVA immobilized lipase, including also satisfactory half-life and good storage stability.Keywords: lipase; hybrid support; adsorption. INTRODUÇÃOEnzimas na sua forma nativa (enzimas livres) têm sido usadas por séculos na indústria de alimentos e mais recentemente nas indústrias farmacêuticas e químicas 1 . Sua estrutura e modo de ação vêm sendo gradativamente elucidados por métodos experimentais bem estabelecidos, como técnicas clássicas de Raio-X e avançadas de Ressonância Nuclear Magnética (RNM). Modernas metodologias de engenharia genética têm possibilitado a produção de enzimas em larga escala ou a modificação de sua estrutura primária, alterando, portanto, algumas de suas características físico-químicas e biológicas 2 . De igual significância são as recentes técnicas de evolução direcionada, as quais têm permitido, via modificação do DNA, a preparação de enzimas especialmente dirigidas para uma determinada finalidade, isto é, enzimas que atuam em valores extremos de pH e temperatura, bem como em presença de meios não convencionais (solventes orgânicos, fase gasosa e CO 2 supercrítico) 3 .O valor de venda de enzimas para uso em indústrias de alimentos, detergentes, especialidades químicas perfizeram um total de aproximadamente US$ 700 milhões em 1992 e aumentaram para US$ 2 bilhões em 2004 4 . De acordo com as projeções, o crescimento no mercado de enzimas é de aproximadamente 4-5% ao ano, acompanhada pela redução de preço, devido ao grande núme-ro de empresas que vêm comercializando enzimas com preços mais competitivos. Como resultado, o mercado previsto para 2009 é da ordem de 2,4 bilhões 4 .De interesse particular é o aumento do uso de enzimas imobilizadas, termo empregado por Katchalski-Katzir 5 na primeira Conferência de Engenharia Enzimática realizada em Henniker, NH, EUA em 1971, para designar enzima fisicamente confinada ou localizada numa certa região do espaço, com retenção de sua atividade catalítica, podendo ser usada repetida e continuamente 6 . Nesta técnica, a enzima fica retida no interior (poros) ou na superfície de u...

1. single nephron pressures, flows and resistances were studied in 17-18 week old genetically hypertensive and normotensive Kyoto rats resembling one another in renal total filtration rate, morphology and number of glomeruli in the kidney.2. Glomerular capillary pressures were similar Introduction in the two groups; however, the hypertensive rats had lower pressures at the end of the efferent Genetic factors play an important in the arteriole than did the normotensive development of essential and experimental hyper-Nephron filtration rates were similar in both tension (Dahl, Heine & Tassinary, 1962;Okamoto

Fruit leathers are made by drying a very thin layer of fruit puree to obtain a chewy product. The objective of this work was to minimise the drying time required to produce mango leathers with no preservatives and no sugar added, and to evaluate their acceptance and storage stability. Mango puree was spread on Petri dishes and oven-dried according to a central composite design with two independent variables: drying temperature (60-80°C) and puree load (0.4-0.6 g cm )2 ). The minimum drying time (120 min) resulted from drying a puree load of 0.5 g cm )2 at 80°C. The product was well accepted, especially in terms of flavour. The mango leathers were packed in polypropylene buckets and stored at 25°C. The combination between low water activity (0.62) and low pH (3.8) allowed the product to be microbiologically stable for at least 6 months, without the need for chemical preservatives.

This study aimed to characterize the safety and technological properties of Enterococcus faecium strains isolated from Brazilian Coalho cheeses. High levels of co-aggregation were observed between Enterococcus faecium strains EM485 and EM925 and both Escherichia coli and Clostridium perfringens . Both strains presented low levels of hydrophobicity. E. faecium EM485 and EM925 were both able to grow in the presence of 0.5% of the sodium salts of taurocholic acid (TC), taurodeoxycholic acid (TDC), glycocholic acid (GC), and glycodeoxycholic acid (GDC), although they showed the ability to deconjugate only GDC and TDC. Both strains showed good survival when exposed to conditions simulating the gastro intestinal tract (GIT). When tested for the presence of virulence genes, only tyrosine decarboxylase and vancomycin B generated positive PCR results.

Based on screening for potential beneficial lactic acid bacteria from Coalho cheese produced in the North-East region of Brazil, eight strains belonging to Lactobacillus rhamnosus and Lactobacillus plantarum were selected. All investigated strains presented low levels of hydrophobicity. Different levels of coaggregation were Dairy Sci. & Technol. (2015) 95:209-230 DOI 10.1007 observed for tested Lb. rhamnosus and Lb. plantarum with Listeria monocytogenes. All strains were able to grow in presence of 0.5% of the sodium salts of taurocholic acid (TC), taurodeoxycholic acid (TDC), and glycocholic acid (GC) and showed the ability to deconjugate only TC, TDC, and GC. Investigated Lb. rhamnosus and Lb. plantarum strains showed good survival when exposed to the conditions simulating the GIT conditions. Lb. rhamnosus and Lb. plantarum strains were tested for presence of virulence, antibiotic resistance, and biogenic amine production genes. In addition, minimum inhibititory concentration (MIC) of selected antibiotics was determined. Production of antimicrobial peptides (bacteriocins) was investigated. However, only Lb. rhamnosus EM253 produced bacteriocin at level 800 arbitrary unit (AU) mL −1 against L. monocytogenes 211. The bacteriocin remained stable at pH from 2.0 to 10.0 and after exposure at 100°C for 120 min and in presence of surfactants and salts. Studied Lb. rhamnosus and Lb. plantarum strains showed good potential to be applied as a functional coculture/s with beneficial properties in the production of Coalho cheese.

Mucor miehei lipase was immobilized on magnetic polysiloxane-polyvinyl alcohol particles by covalent binding. The resulting immobilized biocatalyst was recycled by seven assays, with a retained activity around 10% of its initial activity. K m and V max were respectively 228.3 lM and 36.1 U mg of protein )1 for immobilized enzyme. Whereas the optimum temperature remained the same for both soluble and immobilized lipase (45°C), there was a shift in pH profiles after immobilization. Optimum pH for the immobilized lipase was 8.0. Immobilized enzyme showed to be more resistant than soluble lipase when assays were performed out of the optimum temperature or pH.

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Avaliou-se a qualidade microbiológica de 15 amostras de hortaliças/tubérculos e de 15 amostras de frutas minimamente processadas, comercializadas em Fortaleza (CE). Foram realizadas análises de coliformes fecais e totais, pesquisa de Salmonella sp., contagem total de bolores e leveduras, contagem de Staphylococcus coagulase positiva e contagem total de psicrotróficos. Detectou-se a presença de Salmonella em 66,6% das amostras de hortaliças/tubérculos e em 26% das de frutas. Foi verificado que 13,3% das amostras de hortaliças/ tubérculos apresentaram contagem de coliformes fecais acima do limite estabelecido pela legislação brasileira. Contagens elevadas de coliformes totais, de bolores e leveduras e de psicrotróficos também foram encontradas em ambos os produtos, indicando condições inadequadas de higiene durante o processamento, comprometendo seu armazenamento e sua qualidade microbiológica.