L'objectif de cette thèse est d'appliquer la méthode d'identification bactérienne par spectrométrie de masse MALDI-TOF pour une utilisation en routine dans un laboratoire de microbiologie clinique. Dans un 1er temps et de manière prospective, nous avons évalué la performance et le coût-efficacité de l'identification bactérienne de routine par MALDI-TOF par rapport aux techniques conventionnelles d'identification phénotypique. Durant la période des 16 semaines d'étude, nous avons comparé la performance de la technique par MALDI-TOF aux techniques conventionnelles d'identification phénotypique comprenant la coloration de Gram, la galerie API ANA et le Vitek 2. En cas de résultats discordants entre ces deux techniques, l'identification était réalisée par biologie moléculaire. Nous avons montré que le MALDI-TOF est un moyen efficace et rentable pour l'identification des bactéries de routine. Le MALDI-TOF peut être utilisée en 1ère intention dans l'identification bactérienne avant l'ensemble de techniques phénotypiques. Dans un 2ème temps, nous avons évalué rétrospectivement la performance et le coût-efficacité de l'utilisation exclusive de MALDI-TOF en diagnostic bactériologique de routine en comparaison avec les techniques conventionnelles. En analysant les données des 11 dernières années, nous avons montré que le MALDI-TOF est efficace et tout à fait adaptée pour l'identification d'espèce bactérienne en routine. Nous avons également prouvé que MALDI-TOF est un outil puissant pour identifier les espèces bactériennes rarement impliquées dans les infections humaines. Cette technique pourrait être une alternative aux méthodes moléculaires dans le laboratoire clinique. / The objective of this thesis is to apply the method of bacterial identification by MALDI-TOF MS in daily practice in a routine clinical microbiological laboratory. Firstly, we prospectively evaluated the performance and the cost-effective of bacterial identification by MALDI-TOF in comparison with conventional phenotypic identification methods. During a 16-week study, we compared the performance of MALDI-TOF with conventional techniques of identification including Gram staining, API ANA identification strip and automated identification using the Vitek 2. The unmatched identifications between MALDI-TOF and conventional methods were resolved by molecular identification. In this study, we showed that MALDI-TOF was an effective tool and less expensive for the rapid identification of bacterial species in clinical microbiology laboratory. MALDI-TOF can be used in first intention for identification before Gram staining or other phenotypic identification techniques based on physicochemical properties of bacteria. Secondly, we retrospectively evaluated the performance and the cost-effectiveness of the exclusive use of MALDI-TOF in bacteriological diagnosis in comparison with conventional phenotypic identification. 11-year retrospective analysis of data showed that MALDI-TOF was efficient and completely adapted for the routine identification of bacterial species. We also showed that MALDI-TOF had capacity to identify bacterial species that were rarely involved in human diseases. This technique could be an alternative to molecular methods in the clinical laboratory.

Der Klimawandel bedroht Ökosysteme auf der ganzen Welt. Besonders der Anstieg in Länge, Intensität und Häufigkeit von Dürren kann bedeutenden Einfluss auf den globalen Kohlenstoffkreislauf haben. Die Frage, ob Pflanzen und Mikroorganismen anfällig gegenüber ökologischem Stress wie Dürren sind, wurde bereits in vielen Studien für verschiedene Ökosysteme und mit verschiedenen Ansätzen untersucht, aber Analysen von Dürreauswirkungen, die ober- und unterirdische Interaktionen von Pflanzen und Mikroorganismen mit einbeziehen, sind eher selten. Deshalb wird in der vorliegenden Studie die Frage erörtert, wie Trockenheit und/oder Hitze die Interaktionen von Pflanzen und Mikroorganismen in Bezug auf ihre Kohlenstoff-Verbindung beeinflussen. Dies dient zur Bestimmung der Stärke der Pflanze-Mikroorganismen-Kohlenstoff-Verbindung, wenn das Ökosystem an seine Grenzen gebracht wird. Der Fokus liegt deshalb auf durch Trockenstress und Hitze hervorgerufenen Veränderungen in der ober-unterirdischen Kohlenstoff-Dynamik in zwei vom Klimawandel bedrohten Ökosystemen. Es wurde untersucht, wie extreme Klimaereignisse, deren Häufigkeit in Zukunft weiter ansteigen soll, die Kohlenstoff-Verbindung zwischen Pflanzen und Mikroorganismen beeinflusst und wie mikrobielle Gemeinschaften unter diesen Umständen reagieren, um die Resistenz und Reaktionsmechanismen von Ökosystemen im zukünftigen Klimawandel besser vorhersagen zu können. In Kapitel 4 wurde ein Buchenwaldunterholz-Ökosystem untersucht. Buchenwaldmonolithen wurden einem extremen Klimaereignis (Trockenheit und/oder Hitze) ausgesetzt. Die Stärke der Pflanze-Mikroorganismen-Kohlenstoff-Verbindung und Veränderungen in der mikrobiellen Gemeinschaftsstruktur und -aktivität wurden mithilfe von stabilen 13C Isotopenmethoden und Ansätzen auf molekularer Basis, wie 16S rRNA- und Phospholipid-Analysen, bestimmt. In Kapitel 5 wurde ein kleines aquatisches Ökosystems untersucht. Zwei emerse aquatische Makrophyten, Phragmites australis und Typha latifolia, wurden in einem Mesokosmos-Experiment mit Sediment aus einem Soll einer einmonatigen Dürre ausgesetzt. Mithilfe einer 13CO2 Pulsmarkierung, sowie PLFA- und nicht-strukturbildenden Kohlenhydrat-Analysen wurde Kohlenstoff von den Blättern in die Wurzeln bis ins Sediment verfolgt, wo er teilweise in mikrobielle Phospholipide eingebaut wird. Diese Studie hat gezeigt, dass die zwei untersuchten Ökosysteme Trockenstress und Hitze relativ gut widerstehen können, zumindest kurzfristig, und dass das Kohlenstoff-Kontinuum, beziehungsweise die Verbindung zwischen ober- und unterirdischen Gemeinschaften, auch unter starkem Stress intakt bleibt. Zusammenfassend scheint es, dass Ökosysteme stark von einem funktionierenden Pflanze-Boden/Sediment-Mikroorganismen Kohlenstoff-Kontinuum abhängen und versuchen, es auch unter starkem Stress zu erhalten, was möglicherweise dazu beiträgt, dem Anstieg von extremen Dürreperioden aufgrund des Klimawandels besser zu widerstehen. / Climate change is threatening ecosystems around the world. Especially the increase in duration, intensity, and frequency of droughts can have a considerable impact on the global carbon cycle. The question whether plants and microbes are susceptible to environmental stress like drought has been assessed in many studies for different ecosystem types and by using numerous approaches, but research on drought effects that includes above- and belowground interactions is rather scarce. Therefore, the present study assesses the question of how drought and/or heat influence the interactions of plants and microbes, especially the carbon coupling, in order to determine the strength of plant-microbe carbon linkages when an ecosystem is pushed to its limits. The focus of this study thus lies on changes in aboveground-belowground carbon dynamics and the subsequent effects on the soil microbial community under drought and/or heat stress in two climate-threatened ecosystems. It was evaluated how extreme climate events, that are predicted to be more frequent in the near future, affect the carbon coupling between plants and microorganisms and how microbial communities respond under these circumstances, in order to be able to better predict ecosystem resistance and response mechanisms under future climate change. In chapter 4 a beech forest understory ecosystem was investigated. An extreme climate event (drought and/or heat) was imposed on beech forest monoliths and the strength of the plant-microbe carbon linkages and changes in the microbial community structure and activity were determined by using stable 13C isotope techniques and molecular-based approaches like 16S rRNA and microbial phospholipid-derived fatty acid (PLFA) analysis. In chapter 5 a small aquatic ecosystems was investigated. Two emergent aquatic macrophytes, Phragmites australis and Typha latifolia, were grown on kettle hole sediment and then exposed to a month-long summer drought in a mesocosm experiment. By conducting a 13CO2 pulse labeling as well as PLFA and non-structural carbohydrate analyses, the fate of carbon was traced from the plant leaves to the roots and into the sediment, where some of the recently assimilated carbon is incorporated into microbial PLFAs. Overall, this study showed that the two investigated ecosystems can endure environmental stress like heat and drought relatively well, at least in the short-term, and that the carbon continuum, or the linkage between above- and belowground communities, remained intact even under severe stress. In conclusion, it seems that ecosystems strongly depend on and try to maintain a functional plant-soil/sediment microorganism carbon continuum under drought, which might help to withstand the increase in extreme drought events under future climate change.

Morphological diversity of 61 Anabaena populations of 13 morphospecies was described under the field conditions of Czech fishponds and reservoirs. Polyphasic approach was then applied in classification of 45 clonal strains isolated from those populations. Detailed morphological analyses were performed and partial 16S rRNA gene sequences were obtained for 33 of the strains, and secondary metabolite production was evaluated in 20 strains. Plasticity of morphological characteristics under varied conditions of light, temperature, nitrogen and phosphorus was studied in selected strains, as well as their temperature and light growth requirements. The results were then discussed with respect to the delimitation of single Anabaena morphospecies. A new genus Sphaerospermum was defined for the morphospecies Anabaena kisseleviana, A. reniformis and Aphanizomenon aphanizomenoides, whose phenotypic and genotypic features differed considerably from all other Anabaena morphospecies. Unique information was provided on the occurrence and distribution of A. reniformis and Aph. aphanizomenoides in the Czech Republic.

We investigated the effects of substrate (cellulose or starch) and different clay contents on the production of microbial extracellular polymeric substances (EPS) and concomitant development of stable soil aggregates. Soils were incubated with different amounts of montmorillonite (+ 0.1%, + 1%, + 10%) both with and without two substrates of contrasting quality (starch and cellulose). Microbial respiration (CO2), biomass carbon (C), EPS-protein, and EPS-polysaccharide were determined over the experimental period. The diversity and compositional shifts of microbial communities (bacteria/archaea) were analysed by sequencing 16S rRNA gene fragments amplified from soil DNA. Soil aggregate size distribution was determined and geometric mean diameter calculated for aggregate formation. Aggregate stabilities were compared among 1–2-mm size fraction. Starch amendment supported a faster increase than cellulose in both respiration and microbial biomass. Microbial community structure and composition differed depending on the C substrate added. However, clay addition had a more pronounced effect on alpha diversity compared to the addition of starch or cellulose. Substrate addition resulted in an increased EPS concentration only if combined with clay addition. At high clay addition, starch resulted in higher EPS concentrations than cellulose. Where additional substrate was not provided, EPS-protein was only weakly correlated with aggregate formation and stability. The relationship became stronger with addition of substrate. Labile organic C thus clearly plays a role in aggregate formation, but increasing clay content was found to enhance aggregate stability and additionally resulted in the development of distinct microbial communities and increased EPS production.

Le microbiome intestinal humain est une importante communauté de microorganismes, spécifique aux individus et aux populations, dont la composition est influencée par de nombreux facteurs, tels que la génétique et les habitudes de vie de son hôte. La diète est cependant un élément majeur façonnant sa structure. Les influences de plusieurs diètes humaines sur le microbiome ont été largement investiguées. Toutefois, l’impact des variations saisonnières inhérentes à certaines diètes est peu connu. La diète traditionnelle inuite est un exemple de régime alimentaire riche en graisses et protéines animales qui varie temporellement en fonction de la disponibilité saisonnière des ressources. Afin d’étudier les dynamiques temporelles du microbiome intestinal inuit en réponse à la diète traditionnelle, des échantillons de papier hygiénique contenant des selles ont été récoltés auprès d’un groupe de volontaire Inuits du Nunavut (Canada) durant huit mois. Un groupe contrôle de Montréalais (Québec, Canada) de descendance européenne, consommant une diète typiquement occidentale, a également été sollicité. La diversité et la composition du microbiome ont été caractérisées par le séquençage de la région V4 de l’ARNr 16s. Les microbiomes obtenus par un échantillonnage de papier hygiénique et de selles ont été comparés. Ces deux méthodes offrent des représentations similaires mais non-identiques du microbiome intestinal. À partir du séquençage d’échantillons de papier hygiénique, nous avons trouvé que les variations inter-individuelles du microbiome sont plus importantes que les variations intra-individuelles au sein de Montréal et du Nunavut. Des différences significatives de la composition du microbiome s’expliqueraient par la consommation différentielle de certains groupes alimentaires. Bien qu’aucune différence saisonnière marquée n’ait été observée, en termes de composition, le microbiome fluctue davantage à travers le temps chez les individus inuits. Ces résultats suggèrent que le microbiome inuit pourrait être façonné par une diète plus variable. Ensemble, nos résultats suggèrent que la diète traditionnelle a encore un impact important sur la composition, la diversité et la stabilité de microbiome inuit, malgré les transitions alimentaires vécues au Nunavut. / The human gut microbiome represents a diverse microbial community specific to individuals and populations, which is heavily influenced by factors such as genetics and lifestyle. Diet is a major force shaping the gut microbiome, and the effects of dietary choices on microbiome composition have been thoroughly investigated. It has been shown that a change in diet also changes the gut microbiome, but the effects of seasonal diets are poorly known. The traditional Inuit diet is primarily based on animal products, which vary seasonally based on prey availability. To investigate the dynamics of the Inuit diet over time, we collected gut microbiome samples from Inuit volunteers living in Resolute Bay (Nunavut, Canada), and compared them to samples collected from individuals of European descent living in Montréal (Québec, Canada) and consuming a typical Western diet. We sequenced the V4 region of the 16S rRNA gene to characterize the diversity and composition of the Inuit microbiome, and surveyed differences among samples collected with toilet paper or from stool. Our results show that these sampling methods provide similar, but non-identical portraits of the microbiome. Based on sequencing from toilet paper samples alone, we found that inter-individual variations of the microbiome community composition were greater than within-individual variations, both in Nunavut and Montreal, with significant differences in microbiome explained by dietary preferences. No defined seasonal shift of microbiome composition was detected in samples collected over time. However, within-individual microbial diversity fluctuated more with time in Nunavut than in Montreal. Together, these results underline that the traditional Inuit diet still has an important impact on the composition, diversity and stability of the Inuit gut microbiome, even if the traditional seasonality of the diet is less pronounced than expected, due to an increasingly westernized diet in Nunavut.

No description available.

With the advent of industrialization and food processing techniques the sizes of the cereal bran have been drastically reduced. In my thesis, I have tested the effect, if any, of wheat bran and maize bran particle size, in vitro, on the gut microbiota community structure by 16S rRNA sequencing and their function, by Short chain fatty acids (acetate, propionate, butyrate) production. In turn, we also linked the microbiota and SCFA differences to different chemical composition amongst variously sized fractions of wheat and maize bran.

O presente trabalho teve como objetivos caracterizar uma coleção de 98 bactérias isoladas de amostras de petróleo e água de formação de reservatórios da Bacia de Campos (RJ) utilizando técnicas de taxonomia molecular e avaliar o potencial de degradação de biomarcadores do petróleo. O sequenciamento e análise filogenética do gene RNAr 16S revelaram Bacillus firmus, megaterium, pumilus, sphaericus, simplex, cereus/B. thuringiensis Marinobacter lutaoensis, Halomonas shengliensis/H. alimentaria/ H.campisalis, Citreicella thiooxidans, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Micrococcus luteus, Kocuria rosea, Streptomyces alboniger/S. chartreusis /S. moderatus, Staphylococcus hominis e Staphylococcus pasteuri/S. warneri. Os resultados evidenciaram a preferência pela biotransformação do ácido nonadecanóico e esqualano. A caracterização da microbiota presente nos reservatórios e avaliação do potencial de biodegradação pode contribuir para fornecer subsídios para estudos futuros sobre os mecanismos biológicos responsáveis pela biodegradação do petróleo. / This study is aimed to characterize a collection of 98 bacteria isolated from oil and formation water samples derived from reservoirs of the Campos Basin (RJ) using molecular biology-based techniques and to evaluate the degradation potential of petroleum biomarkers. Further sequencing and phylogenetic analysis of 16S rRNA genes revealed species of Bacillus firmus, megaterium, pumilus, sphaericus, simplex, cereus/thuringiensis, Marinobacter lutaoensis, Halomonas shengliensis/H. alimentaria/H. campisalis, Citreicella thiooxidans, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Micrococcus luteus, Kocuria rosea, Streptomyces alboniger/S. chartreusis/S. moderatus, Staphylococcus hominis and Staphylococcus pasteuri/S. warneri. The results showed the preference of bacteria for the biotransformation of nonadecanoic acid and squalane. The characterization of the microbiota associated to reservoirs and the evaluation of their biodegradation potential may provide subsidies for future studies about the biological mechanisms responsible for petroleum biodegradation.

A afiliação genérica de Fischerella e Hapalosiphon é problemática devido à instabilidade dos caracteres morfológicos. Os gêneros Fischerella e Hapalosiphon são diferenciados pela presença de tricoma multisseriado e uni ou bisseriado, respectivamente. Porém, geneticamente esses caracteres não se mostraram diacríticos para diferenciar gêneros. Estudos moleculares de linhagens isoladas de ecossistemas brasileiros são escassos para Fischerella e inexistentes para Hapalosiphon. Neste estudo, oito linhagens de cianobactérias, pertencentes à família Hapalosiphonaceae, isoladas de água doce e solos brasileiros foram caracterizadas morfologicamente e geneticamente e analisadas para a produção de substâncias bioativas. As análises morfológicas identificaram cinco morfotípos de Fischerella (CENA19, CENA161, CENA212, CENA213, CENA214) e três de Hapalosiphon (CENA63, CENA71, CENA72). As análises filogenéticas do RNAr 16S usando neighbor-joining (NJ) e máxima verossimilhança (MV) colocaram todas as linhagens isoladas em um agrupamento com alto suporte (reamostragens de 99% NJ e MV) contendo membros da ordem Nostocales. Além disso, as linhagens de Fischerella selecionadas para o estudo agruparam-se em um clado interno com alto valor de reamostragem (100% NJ e 86% MV), com exceção da Fischerella CENA19. A posição dessa estirpe na árvore filogenética indica que necessita de revisão taxonômica. As linhagens de solo Hapalosiphon CENA71 e CENA72 também formaram um clado interno separado (99% NJ e 98% MV), mas a linhagem de água doce CENA63 foi colocada em um clado diferente (com valores de reamostragens de 99% NJ e MV), juntamente com linhagens do gênero Hapalosiphon e Westielopsis prolífica SAG 16.93, oriundas de solo. A comparação das análises filogenéticas individuais de regiões dos genes RNAr 16S, rpoC1, rbcL, tufA, e cpcBA-IGS das três linhagens de Hapalosiphon e de duas linhagens de Fischerella, CENA19 e CENA161, mostrou resultados incongruentes devido as diferentes taxas evolutivas desses genes. No entanto, a análise filogenética concatenada desses genes, mostrou que a Fischerella CENA19 agrupou com as duas linhagens de Hapalosiphon CENA71 e CENA72, com alto valor de reamostragem (100%), enquanto que a Fischerella CENA 161 e a Hapalosiphon CENA63 posicionaram-se cada uma em clados separados. Os resultados indicam que a nomenclatura das linhagens de cianobactérias da família Hapalosiphonaceae necessita de revisão. Os extratos intra e extracelulares das linhagens Fischerella sp. CENA161 e CENA19 e Hapalosiphon sp. CENA71 e CENA72 mostraram efeitos inibitórios no crescimento de bactérias patogênicas. As análises em espectrômetro de massas Q-TOF MS/MS indicaram a putativa presença de aeruginopeptina, cianopeptolina, fischerelina, aeruginosina, oscilapeptilida, microcistinas e ácido tumonóico nos extratos. No extrato intracelular da Fischerella sp. CENA161 identificou-se três ou quatro variantes de microcistinas, LR, LL, FR e/ou M(O)R. Fragmentos dos genes mcyA, mcyB, mcyC, mcyD, mcyE, mcyG e mcyI dessa linhagem foram seqüenciados. Nas duas análises filogenéticas realizadas com sequências de aminoácidos de McyE e sequências concatenadas de McyD, McyE e McyG, as enzimas da microcistina sintetase ficaram agrupadas de acordo com os gêneros de cianobactérias indicando um padrão de evolução / The generic affiliation of Fischerella and Hapalosiphon is problematic due to instability of morphological characters. The Fischerella and Hapalosiphon genera are differentiated by the presence of trichome multisseriate and uni or bisseriate, respectively. However, genetically these characters were not diacritical to distinguish genera. Molecular studies of strains isolated from Brazilian ecosystems are scarce for Fischerella and absent for Hapalosiphon. In this study, eight cyanobacterial strains, belonging to Hapalosiphonaceae family, isolated from Brazilian freshwater and soil were morphologically and genetically characterized and analyzed for bioactive compound productions. The morphological analyses identified five Fischerella (CENA19, CENA161, CENA212, CENA213, CENA214) and three Hapalosiphon (CENA63, CENA71, CENA72) morphotypes. The neighbor-Joining (NJ) and maximum likelihood (ML) phylogenetic analyses of 16S rRNA placed all isolated strains in high supported (99% NJ and ML of bootstrap) cluster containing members of the order Nostocales. Furthermore, the Fischerella strains studied were grouped in an internal clade with high bootstrap value (100% NJ and 86% ML), with exception of Fischerella CENA19. The position of this strain in the phylogenetic tree indicates that it needs taxonomical revision. The soil Hapalosiphon strains CENA71 and CENA72 also formed a separated tight internal clade (99% NJ and 98% ML), but the freshwater strain CENA63 was placed in a different clade (99% NJ and ML of bootstrap value) together with Hapalosiphon strains genera and Westielopsis prolifica SAG 16.93, originated from soil. The comparison of the phylogenetic analyses of individual regions of the genes 16S rRNA, rpoC1, rbcL, tufA, and cpcBA-IGS from the three Hapalosiphon strains and the two Fischerella strains CENA19 and CENA161 showed incongruent results due to different evolutionary rates of these genes. However, the concatenated phylogenetic analysis of these genes, showed that Fischerella CENA19 grouped with the two Hapalosiphon strains CENA71 and CENA72 with high bootstrap value (100%), while Fischerella CENA 161 and Hapalosiphon CENA63 were positionated each one in separate clades. The results indicate that the nomenclature of cyanobacterial strains from the family Hapalosiphonaceae needs revision. The intra and extracellular extracts of the Fischerella sp. strains CENA161 and CENA19 and Hapalosiphon sp. strains CENA71 and CENA72 showed inhibitory effects on the growth of pathogenic bacteria. The analysis in the mass spectrometer Q-TOF MS/MS indicated the presence of aeruginopeptin, cyanopeptolin, fischerellin, aeruginosin, oscillapeptilide, microcystins and tumonoic acid in the extracts. In the intracellular extracts of Fischerella sp. CENA161, three or four variants of microcystins, LR, LL, FR and/or M(O)R, were identified. Fragments of genes mcyA, mcyB, mcyC, mcyD, mcyE, mcyG and mcyI of this strain were sequenced. In both phylogenetic analyses performed with amino acid sequences of McyE and concatenated sequences of McyD, McyE and McyG, the microcystin synthetase enzymes were grouped according to the cyanobacterial genera, indicating a pattern of evolution

O presente trabalho teve por objetivo avaliar a eficiência de remoção do surfactante aniônico alquilbenzeno linear sulfonado (LAS) em reator anaeróbio de leito granular expandido - EGSB (1,5 litros) com recirculação e alimentação com meio mineral. Além de caracterizar filogeneticamente a diversidade de bactérias na presença do surfactante. O sistema foi operado em condição mesofílica em 4 etapas: (I), (II) e (IV) com TDH de 32 horas, e (III) com TDH de 26 horas. Em todas as etapas a DQO foi em média de 609 \'+ OU -\' 137 mg/L e 14 \'+ OU -\' 1,71 mg/L de LAS afluente. As maiores remoções de LAS foram verificada nas etapas II e IV, com valores de 73,6 \'+ OU -\' 5,6% e 63,6 \'+ OU -\' 6,17%, respectivamente de. Na etapa III essa remoção foi de 47,8 \'+ OU -\' 6,2%. Por meio do balanço de massa constatou-se que 56,6% do total de LAS adicionado foram removidos compreendendo 48,4% por biodegradação e 8,2% por adsorção. A remoção de matéria orgânica não foi afetada com a adição do LAS e nem pela exposição prolongada a esse surfactante. Entretanto, a estrutura do grânulo foi comprometida quando da adição do surfactante, observado pelo aumento da concentração de sólidos totais efluente de 0,049 g/L na etapa I (sem LAS), 0,128 g/L na etapa II, 0,064 g/L na etapa III e 0,038 g/L na etapa IV, quando da adição de 14 \'+ OU -\' 1,71 mg LAS/L. Além disso, foi notada diminuição do diâmetro médio dos grânulos no decorrer da operação do reator de 0,36 cm nas etapas I e III para 0,34 cm na etapa IV. Por meio da técnica de tubos múltiplos (NMP) foi constatado aumento das bactérias anaeróbias totais e diminuição das arqueias metanogênicas, em função do tempo de operação do reator. As bactérias redutoras de ferro representaram 8% da biomassa anaeróbia na etapa IV. Por meio do seqüenciamento da região 16S do RNAr para o domínio Bacteria da biomassa da extremidade superior do reator e da biomassa do leito, foi verificado semelhança com os seguintes filos Proteobacteria, Firmicutes e Synergistetes. Notou-se diferença significativa entre as bibliotecas de clones para essas duas amostras. / This study aimed to evaluate the efficiency of removal of linear alkylbenzene sulfonate (LAS) in expanded bed reactor (1.5 liters) using granular sludge (EGSB) with recirculation and feed with mineral medium modified. The system was operated at mesophilic condition in four stages: (I) (II) and (IV) with HRT of 32 hours, and (III) with HRT of 26 hours. At all stages the COD averaged 609 \'+ OR -\' 137 mg/L and 14 \'+ OR -\' 1.71 mg/L LAS influent. The higher removals of LAS were found in stages II and IV, respectively, 73.6 \'+ OR -\' 5.6% and 63.6 \'+ OR -\' 6.17%. In stage III this removal was 47.8 \'+ OR -\' 6.2%. Through mass balance was found that 56.6% of total LAS added were removed by biodegradation comprising 48.4% and 8.2% by adsorption. The organic matter removal was not affected by the addition of LAS and not by prolonged exposure to this surfactant. However, the granule structure was compromised after the addition of surfactant, the observed increase in effluent total solids concentration of 0.049 g/L in stage I (no LAS), 0.128 g/L in stage II, 0.064 g/L in stage III and 0.038 g/L in stage IV when adding 14 \'+ OR -\' 1.71 mg/L. Furthermore, it was noticed significant decrease in mean diameter of the granules during the operation of the reactor of 0.36 cm in stages I and III to 0.34 cm in stage IV. Through the multiple tube method (MPN) was found to increase the total anaerobic bacteria and methanogenic archaea decreased depending on the time of reactor operation. Iron-reducing bacteria accounted for 8% of anaerobic bacteria total in step IV. By sequencing the 16S rRNA for the domain Bacteria biomass from the upper end of the reactor and the biomass of the bed, was found similar to the following phyla Proteobacteria, Firmicutes and Synergistetes. Significant difference was noted between the clone libraries for these two samples.