Solid-state fermentation with orange waste: optimization of Laccase production from Pleurotus pulmonarius CCB-20 and decolorization of synthetic dyes

Laccases are oxidoreductase enzymes that have the ability to oxidize phenolic substrates. Its biotechnological potential has been greatly explored in many areas as biotechnology industry, bioremediation of dyes, food industry and environmental microbiology. The aim of this study was maximize the laccase production by Pleurotus pulmonarius (Fr.) Quélet in solid-state fermentation (SSF) using orange waste as substrate. After optimization the capability of the crude laccase to decolorize dyes was analyzed. The fermentation medium in the solid-state was optimized by applying a factorial design. After statistics optimization, laccase activity increased two times. The laccase activity appears to be correlated with the ability of crude extract to decolorize some industrial dyes. The optimized laccase was characterized with respect to optimum pH, influence of temperature and salts. Our results demonstrate that P. pulmonarius was an efficient producer of an important industrial enzyme, laccase, in a cheap solid-state system using orange waste as substrate.

Gene expression analysis identifies hypothetical genes that may be critical during the infection process of Xanthomonas citri subsp. citri

Background: Gene expression analysis via microarray is widely used in phytobacteria to validate differential gene expression associated with virulence or to compare biological profiles of wild type and mutant strains. Here, we employed DNA microarrays to study the early stages of the infection process (24, 72 and 120 h post-inoculation) of Xanthomonas citri subsp. citri (Xac) infecting Citrus sinensis to interrogate the expression profiles of hypothetical genes. Results: Under infective conditions, 446 genes were up- and 306 downregulated. Outstanding among genes upregulated during infection were those involved in synthesizing the Type 3 Secretion System and effectors, xanthan gum and quorum-sensing induction, and flagellum synthesis and regulation. Additionally, 161 hypothetical genes were up- and 100 were downregulated, 49 of which are known to have a significant biological role. To understand hypothetical gene co-regulation or -expression, nine expression profiles including 158 genes were identified during the three infection phases. Of these, 47 hypothetical genes were identified as having expression profiles associated with at least one connected to a gene associated with adaptation and virulence. Conclusions: Expression patterns of six differentially expressed genes were validated by quantitative reverse transcription polymerase chain reaction, thus demonstrating the effectiveness of this tool in global gene expression analysis in Xac.

Pesquisa de coliformes totais e termotolerantes em suco de laranja in natura e correlação com as condições higienicossanitárias do estabelecimento produtor / Research of total and thermotolerant coliforms in fresh orange juice and correlation with the hygienic sanitary conditions of the producer establishment

Este trabalho teve como objetivo verificar a qualidade microbiológica do suco de laranja in natura por meio de contagem de coliformes totais e termotolerantes e correlacionar os resultados obtidos com as condições de higiene do estabelecimento produtor através da aplicação de um checklist. Foram coletadas quatro amostras de suco de laranja in natura preparadas na hora. As amostras foram analisadas quanto ao Número Mais Provável (NMP) de coliformes totais e termotolerantes pela metodologia de tubos múltiplos de fermentação. O pH 4 foi identificado em todas as amostras. Foram observadas inadequações nos checklist e observou-se também que 50% das amostras analisadas apresentaram contagem de coliformes totais e termotolerantes acima do permitido pela Legislação. Conclui-se que são necessários treinamentos periódicos para os funcionários e proprietário do estabelecimento para que as condições higienicossanitárias sejam adequadas à produção de alimentos sem oferecer riscos à saúde do consumidor.(AU)

Evaluación del efecto de diferentes cepas de levadura (Montrachet, K1-V1116, EC-1118, 71B-1122 y IVC-GRE ®) y clarificantes sobre los atributos sensoriales del vino de naranja criolla (Citrus sinensis) / Evaluation of effect of various strains of yeast (Montrachet, K1-V1116, EC-1118, 71B-1122 y IVC-GRE ®) and clearer on the sensory attributes orange wine (Citrus sinensis)

En este trabajo se evaluó el efecto de diferentes cepas de levadura (Montrachet, K1-V1116, EC-1118, 71B-1122 y IVC-GRE ®) sobre los atributos sensoriales del vino de naranja. Estos atributos fueron medidos utilizando la escala modificada de UC Davis. En una prueba de ordenamiento para determinar el mejor tratamiento de clarificación se determinó que la gelatina por sí sola no causa efecto sobre el atributo apariencia general, la combinación de la gelatina y la microfiltración tienen un efecto positivo sobre la apariencia del vino de naranja. Los cinco vinos tratados con diferentes levaduras presentaron diferencias significativas sobre la puntuación total, acidez total, sabor y calidad en general. En términos del efecto de las levaduras, la evaluación sensorial realizada a los vinos mostró que el de naranja con la levadura K1-V1116 fue el que sobresalió en términos de puntuación en los promedios de casi todos los atributos analizados por el panel sensorial.

In this Wort was evaluated the effect of different types of strains of yeast (Montrachet, K1-V1116, EC-1118, 71B-1122 y IVC-GRE) over the sensorial attributes of orange wines were also studied. These attributes were measured in a modified scale of UC Davis. By using an order test in order to know the best cleared treatment, it was determined that gelatin by itself does not cause any effect over the general quality attribute, but the combination of gelatin and microfiltration, cause a positive effect over the orange wine appearance. The five wines treated with different yeasts presented significant differences on individual scores, total acidy, flavor and general quality of the UC Davis scale. The sensorial evaluation of wines showed that the yeast K1-V1116 produced the best rated orange wine. This wine was significantly different over many attributes when compared with the other wines evaluated by the sensorial panel.

[ comparison of the antimicrobial resistance pattern [antibiotyping] of staphylococcus strains isolated from orange and apple juices with the strains isolated from clinical samples, Shahrekord, Iran, 2007]

One of the main routes in which bacterial resistance is transmitted is through food products. Antibiotic products are widely used in the nature to control diseases. It has been shown that these products can be transmitted to human through meat, milk, fruit, fruit juices and water and consequently they can cause antibiotic resistance problems. The aim of this study was to compare antimicrobial resistance of staphylococcus strains isolated from orange and apple juices and those strains isolated from clinical samples. This descriptive- analytical study was performed on 111 staphylococcus bacteria which were isolated from fruit juices or from patients referring to the educational hospitals in Shahrekord, Iran. Antibiotic susceptibility test was performed by disc diffusion method. The bacteria were classified by antibiotyping. Data were analyzed using Fishers exact test. The results of antibiotyping showed that 111 staphylococcus isolates were distributed in 36 patterns from which 10 isolates [53%] were Staphylococcus aureus belonged to 4 patterns. From the total staphylococcus isolates, 62 isolates [67%], were Staphylococcus epidermidis which were belonged to 11 patterns. These patterns were observed the same in fruit juices and clinical samples [P>0.05]. The rest of isolates [39 isolates] were belonged to 21 patterns. The results of our study showed that most of the staphylococcus isolates were resistant to one or more antibiotics. On the other hand, 65% of isolated samples showed the same antibiotic resistance pattern in fruit juices and clinical samples. It is possible that food products, including fruit juices have role in transmitting bacterial resistance. Therefore, it is necessary to restrict the use of antibiotics and to control the production, transportation and maintenance of fruit juices

Análise microbiológica dos sucos de laranja produzidos e consumidos em alguns municípios da região do Médio Alto Uruguai, RS / Microbiological analysis of orange juice produced and consumed in some municipalities of Medio Alto Uruguai, RS

O mercado de sucos de laranja in natura e pasteurizados vem conquistando clientela nos últimos anos, competindo com refrigerantes e com outros produtos de renome. Com o objetivo de avaliar a qualidade microbiológica desses produtos, foram coletadas e analisadas 05 amostras de suco de laranja in natura e apenas 01 amostra de suco de laranja pasteurizado, produzidos e consumidos na região do Médio Alto Uruguai. Apenas seis marcas, provenientes de cidades diferentes, foram analisadas pois, na pesquisa de produção anteriormente realizada, mostrou-se uma maior produção de sucos de laranja in natura do que pasteurizados. Os resultados desse estudo em sucos de laranja in natura mostraram que 04 amostras apresentaram coliformes totais e termotolerantes, porém, 02 amostras estão nos padrões aceitáveis pela legislação brasileira.(...) Com base nestes resultados, sugerem-se maiores cuidados com a qualidade da matéria prima, com as boas práticas de fabricação, principalmente com o controle sanitário dos manipuladores e equipamentos, assim como o acondicionamento adequado do produto.

Aspectos da contaminação alimentar por Salmonella / Aspects of the alimentary contamination for Salmonella

A importância do controle da qualidade dos alimentos é de fundamental importância, a fim de que sejam eliminados os riscos de contaminação da população por via alimentar, principalmente de patógenos como as bactérias do gênero Salmonella. O objetivo deste trabalho foi abordar questões sobre segurança alimentar, correlacionadas à Salmonella, seus principais aspectos epidemiológicos e a possibilidade da sua transmissão para o homem por alimentos e animais. Foi realizado um levantamento bibliográfico através de bancos de dados internacionais SCIELO, HIGHWIRE e LILACS. Através deste levantamento, podemos concluir que ainda há muito a ser estudado sobre a bactéria Salmonella e suas formas de contaminação no meio, entretanto, com cuidados sobre a qualidade do alimento e uma fiscalização dos manipuladores de alimento, os índices de contaminação e mortalidade diminuirão.

Avaliação microbiológica de sucos de laranja in natura, comercializados na cidade de Pelotas, RS / Microbiological orange juice evaluation in natura, commercialized in the city of Pelotas, RS

O presente trabalho objetivou avaliar a qualidade microbiológica de sucos de laranja “in natura” engarrafados e comercializados na cidade de Pelotas, RS. Apenas uma amostra mostrou-se contaminada por coliformes fecais, porém em número bem abaixo do permitido por lei. Para bolores e leveduras todas as amostras estavam contaminadas, sendo que 60 por cento apresentavam contagem acima dos valores permitidos. Penicillium spp. foi o principal gênero de bolor identificado, estando presente em 67 por cento das amostras. Portanto, é necessário que haja condições higiênico-sanitárias mais adequadas na produção e comercialização destes sucos, a fim de se evitar riscos à saúde do consumidor.

Identification of differentially expressed genes of Xanthomonas axonopodis pv. citri by representational difference analysis of cDNA

Xanthomonas axonopodis pv. citri is a phytopathogenic bacterium responsible for citrus canker, a serious disease which causes severe losses in citriculture around the world. In this study we report the differential expression of X. axonopodis pv. citri in response to specific treatments by using Representational Difference Analysis of cDNA (cDNA RDA). cDNAs from X. axonopodis pv. citri cultured in the presence of leaf extract of the host plant (Citrus sinensis), in vivo, as well as in the complex medium were hybridized against cDNA of the bacterium grown in the minimal medium. Sequencing of the difference products obtained after the second and third hybridizations revealed a total of 37 distinct genes identified by homology searches in the genome of X. axonopodis pv. citri. These genes were distributed in different functional categories, including genes that encode hypothetical proteins, genes involved in metabolism, cellular processes and pathogenicity, and mobile genetic elements. Most of these genes are likely related to growth and/or acquisition of nutrients in specific treatments whereas others might be important for the bacterium pathogenicity.