Loading...
9 results
Search Results
Now showing 1 - 9 of 9
- Acinetobacter rudis sp. nov., isolated from raw milk and raw wastewaterPublication . Vaz-Moreira, Ivone; Novo, Ana; Hantsis-Zacharov, Elionora; Lopes, Ana Rita; Gomila, Margarita; Nunes, Olga C.; Manaia, Célia M.; Halpern, MalkaTwo bacterial strains, G30T and A1PC16, isolated respectively from raw milk and raw wastewater, were characterized using a polyphasic approach. Chemotaxonomic characterization supported the inclusion of these strains in the genus Acinetobacter, with Q-8 and Q-9 as the major respiratory quinones, genomic DNA G+C contents within the range observed for this genus(38–47 mol%) and C16 : 0, C18 : 1v9c and C16 : 1v7c/iso-C15 : 0 2-OH as the predominant fatty acids. The observation of 16S rRNA gene sequence similarity lower than 97% with other Acinetobacter species with validly published names led to the hypothesis that these isolates could represent a novel species. This hypothesis was supported by comparative analysis of partial sequences of the genes rpoB and gyrB, which showed that strains G30T and A1PC16 did not cluster with any species with validly published names, forming a distinct lineage. DNA–DNA hybridizations confirmed that the two strains were members of the same species, which could be distinguished from their congeners by several phenotypic characteristics. On the basis of these arguments, it is proposed that strains G30T and A1PC16 represent a novel species, for which the name Acinetobacter rudis sp. nov. is proposed. The type strain is strain G30T (5LMG 26107T 5CCUG 57889T 5DSM 24031T 5CECT 7818T).
- Sulfide oxidation by heterotrophic P. Koreensis A9 under aerobic conditionsPublication . Novo, Ana; Moreira, Irina S.; Vasconcelos, Isabel; Castro, Paula M. L.
- Antibiotic resistance, antimicrobial residues and bacterial community composition in urban wastewaterPublication . Novo, Ana; André, Sandra; Viana, Paula; Nunes, Olga C.; Manaia, Célia M.This study was based on the hypothesis that the occurrence of antimicrobial residues and antibiotic resistant bacteria in the sewage could be correlated with the structure and composition of the bacterial community and the antibiotic resistance loads of the final effluent. Raw and treated wastewater composite samples were collected from an urban treatment plant over 14 sampling dates. Samples were characterized for the i) occurrence of tetracyclines, penicillins, sulfonamides, quinolones, triclosan, arsenic, cadmium, lead, chromium and mercury; ii) antibiotic resistance percentages for tetracycline, sulfamethoxazole, ciprofloxacin and amoxicillin and iii) 16S rRNA gene-DGGE patterns. The data of corresponding samples, taking into account the hydraulic residence time, was analyzed using multivariate analysis. Variations on the bacterial community structure of the final effluent were significantly correlated with the occurrence of tetracyclines, penicillins, sulfonamides, quinolones and triclosan in the raw inflow. Members of the class Epsilonproteobacteria presented positive correlations with those antimicrobials, whereas negative correlations were observed with Beta and Gammaproteobacteria and Firmicutes. Antibiotic resistance percentages presented different trends of variation in heterotrophs/enterobacteria and in enterococci, varied over time and after wastewater treatment. Antibiotic resistance was positively correlated with the occurrence of tetracyclines residues and high temperature. A relationship between antibiotic residues, bacterial community structure and composition and antibiotic resistance is demonstrated. Further studies, involving more wastewater treatment plants may help to elucidate this complex relationship.
- Studies on Hydrogen Sulfide Oxidase from Pseudomonas sp.Publication . Novo, Ana; Antunes, Filipa; Baptista, Inês; Jorge, Ruben; Saraiva, Isabel; Moreira, Irina S.; Castro, Paula M. L.
- Factors influencing antibiotic resistance burden in municipal wastewater treatment plantsPublication . Novo, Ana; Manaia, Célia M.Municipal wastewater treatment plants are recognized reservoirs of antibiotic-resistant bacteria. Three municipal wastewater treatment plants differing on the dimensions and bio-treatment processes were compared for the loads of amoxicillin-, tetracycline-, and ciprofloxacinresistant heterotrophic bacteria, enterobacteria, and enterococci in the raw inflow and in the treated effluents. The sewage received by each plant, in average, corresponded to 85,000 inhabitant equivalents (IE), including pretreated industrial effluents (≤30%) in plant activated sludge, 105,000 IE, including pretreated hospital effluents (≤15%) in plant trickling filter, and 2,000 IE, exclusively of domestic sewage, in plant submerged aerated filter. The presence of pretreated industrial effluents or of pretreated hospital sewage in the raw inflow did not imply significantly higher densities (per milliliter or per IE) of antibiotic-resistant bacteria in the raw wastewater. Longer hydraulic residence periods (24 h) corresponded to higher bacterial removal rates than shorter periods (12 and 9 h), although such efficiency did not imply significant average decreases in the antibiotic resistance prevalence of the treated effluent. The bacterial loads in the treated effluent could be ranked according to the treatment efficiency, suggesting that the characteristics of the raw inflow may have less relevance on the quality of the treated wastewater than other aspects, such as the inflow volume, the type of biological treatment, or the hydraulic residence time.
- Hydrogen sulfide biological oxidation by pure cultures of heterotrophic bacteriaPublication . Novo, Ana; Antunes, Filipa; Baptista, Inês; Jorge, Ruben; Saraiva, Isabel; Moreira, Irina S.; Castro, Paula M. L.Biogas is a mixture of gases produced during anaerobic treatment of sludge whose composition depends on the type of digested materials as well as on the operating conditions of bioreactor. This consists mainly of CH4 and CO2, but components such as H2S is of particular interest due to its corrosive, toxic and environmentally hazardous properties. Removal of H2S present in biogas can be achieved through physical and chemical processes, which are effective but produce secondary waste, which in turn gives rise to another problem of pollution. Biological treatment can be used to removing H2S using different species of microorganisms whose specific enzymes catalyze the biological oxidation of H2S, including photoautotrophic and chemotrophs organisms. This work aims to compare the biotechnological removal of H2S from biogas in aerobic conditions through heterotrophic microbial biomass and biocatalytic treatments. Heterotrophic microorganisms were isolated from microbial enrichments supplied with H2S streams from a wastewater treatment plant and were characterized based on their ability to grow in mineral medium with acetate as source of carbon. Isolates retrieved were mainly affiliated to the class of γ-proteobacteria with a strong prevalence of the genus Pseudomonas. Isolates A9, B9 and C1 all identified as Pseudomonas spp., revealed as the species with higher potential for H2S removal, growing at concentrations of H2S up to 16 mM. Total protein profiles were screened by SDS-PAGE for the three isolates, before and after the addition of H2S, with the aim of purifying enzyme fractions involved in the oxidation process.
- Ciprofloxacin resistance in domestic wastewater treatment plantsPublication . Manaia, Célia M.; Novo, Ana; Coelho, Bruno; Nunes, Olga C.The potential of domestic wastewater treatment plants to contribute for the dissemination of ciprofloxacin-resistant bacteria was assessed. Differences on bacterial counts and percentage of resistance in the raw wastewater could not be explained on basis of the size of the plant or demographic characteristics of population served. In contrast, the treated effluent of the larger plants had significantly more heterotrophs and enterobacteria, including ciprofloxacin-resistant organisms, than the smaller (p<0.01). Moreover, longer hydraulic retention times were associated with significantly higher percentages of resistant enterobacteria in the treated effluent (p<0.05). Independently of the size or type of treatment used, domestic wastewater treatment plants discharged per day at least 1010–1014 colony forming units of ciprofloxacin-resistant bacteria into the receiving environment.
- Biodegradation of bisphenol A and bisphenol S by labrys portucalensis strain F11Publication . Novo, Ana; Moreira, Irina S.; Castro, Paula
- Pseudomonas koreensis A9 genome insights in heterotrophic sulfide oxidationPublication . Novo, A.; Moreira, I. S.; Vasconcelos, I.; Castro, P. M. L.