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Sample records for aerobic mesophilic bacteria

  1. Comparison of Dry Medium Culture Plates for Mesophilic Aerobic Bacteria in Milk, Ice Cream, Ham, and Codfish Fillet Products

    PubMed Central

    Park, Junghyun; Kim, Myunghee

    2013-01-01

    This study was performed to compare the performance of Sanita-Kun dry medium culture plate with those of traditional culture medium and Petrifilm dry medium culture plate for the enumeration of the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet. Mesophilic aerobic bacteria were comparatively evaluated in milk, ice cream, ham, and codfish fillet using Sanita-Kun aerobic count (SAC), Petrifilm aerobic count (PAC), and traditional plate count agar (PCA) media. According to the results, all methods showed high correlations of 0.989~1.000 and no significant differences were observed for enumerating the mesophilic aerobic bacteria in the tested food products. SAC method was easier to perform and count colonies efficiently as compared to the PCA and PAC methods. Therefore, we concluded that the SAC method offers an acceptable alternative to the PCA and PAC methods for counting the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products. PMID:24551829

  2. Comparison of dry medium culture plates for mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products.

    PubMed

    Park, Junghyun; Kim, Myunghee

    2013-12-01

    This study was performed to compare the performance of Sanita-Kun dry medium culture plate with those of traditional culture medium and Petrifilm dry medium culture plate for the enumeration of the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet. Mesophilic aerobic bacteria were comparatively evaluated in milk, ice cream, ham, and codfish fillet using Sanita-Kun aerobic count (SAC), Petrifilm aerobic count (PAC), and traditional plate count agar (PCA) media. According to the results, all methods showed high correlations of 0.989~1.000 and no significant differences were observed for enumerating the mesophilic aerobic bacteria in the tested food products. SAC method was easier to perform and count colonies efficiently as compared to the PCA and PAC methods. Therefore, we concluded that the SAC method offers an acceptable alternative to the PCA and PAC methods for counting the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products. PMID:24551829

  3. Survival, injury and inactivation of Escherichia coli 0157:H7, salmonella and aerobic mesophilic bacteria in apple juice and cider amended with nisin-edta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For health reasons, people are consuming fresh juices or minimally processed fruit and vegetable juices, thereby, exposing themselves to the risk of foodborne illness if such juices are contaminated with bacteria pathogens. Behavior of aerobic mesophilic bacteria, Escherichia coli O157:H7 and Salmon...

  4. Survival of Yersinia enterocolitica and mesophilic aerobic bacteria on eggshell after washing with hypochlorite and organic acid solutions.

    PubMed

    Favier, G I; Escudero, M E; Mattar, M A; de Guzmán, A M

    2000-08-01

    Populations of Yersinia enterocolitica 0:9 and mesophilic aerobic bacteria on the shell of fresh chicken eggs were assessed prior and after washing with 0.75%, 1%, and 3% acetic and lactic acids, 50, 100, and 200 mg/liter (ppm) of chlorine, and water. Highest reductions of mesophilic aerobic bacterial populations (normal flora) on trypticase soy agar were 1.28 and 2.15 log10 cycles with 100 and 200 mg/liter of chlorine, 0.28 and 0.36 log10 cycles with 1% and 3% acetic acid, and 0.70 and 0.71 log10 cycles with 1% and 3% lactic acid, respectively, as compared to the control group. No Salmonella or Yersinia were detected among the natural flora of the eggs. On Y. enterocolitica O:9-inoculated eggs, reductions of 2.66, 2.77, and 2.92 log10 cycles by 50, 100, and 200 mg/liter of chlorine, of 2.47, 2.48, and 2.49 log10 cycles by 0.75%, 1%, and 3% of acetic acid, and of 2.48 and 2.72 log10 cycles with 1% and 3% of lactic acid, respectively, were observed with respect to the control. Organic acids at 3% caused detachment of the surface cuticle of the eggshell. Y. enterocolitica was more sensitive to the wash treatments than the natural microflora. The absence of potentially pathogenic Y. enterocolitica, observed for other fresh foods, should be a norm for fresh eggs sold in retail stores. PMID:10945580

  5. Preferential Use of Carbon Sources in Culturable Aerobic Mesophilic Bacteria of Coptotermes curvignathus's (Isoptera: Rhinotermitidae) Gut and Its Foraging Area.

    PubMed

    Wong, W Z; H'ng, P S; Chin, K L; Sajap, Ahmad Said; Tan, G H; Paridah, M T; Othman, Soni; Chai, E W; Go, W Z

    2015-10-01

    The lower termite, Coptotermes curvignathus, is one of the most prominent plantation pests that feed upon, digest, and receive nourishment from exclusive lignocellulose diets. The objective of this study was to examine the utilization of sole carbon sources by isolated culturable aerobic bacteria among communities from the gut and foraging pathway of C. curvignathus. We study the bacteria occurrence from the gut of C. curvignathus and its surrounding feeding area by comparing the obtained phenotypic fingerprint with Biolog's extensive species library. A total of 24 bacteria have been identified mainly from the family Enterobacteriaceae from the identification of Biolog Gen III. Overall, the bacteria species in the termite gut differ from those of foraging pathway within a location, except Acintobacter baumannii, which was the only bacteria species found in both habitats. Although termites from a different study area do not have the same species of bacteria in the gut, they do have a bacterial community with similar role in degrading certain carbon sources. Sugars were preferential in termite gut isolates, while nitrogen carbon sources were preferential in foraging pathway isolates. The preferential use of specific carbon sources by these two bacterial communities reflects the role of bacteria for regulation of carbon metabolism in the termite gut and foraging pathway. PMID:26314017

  6. Growth parameters of escherichia coli O157:H7, salmonella and listeria monocytogenes and aerobic mesophilic bacteria of apple cider amended with nisin-EDTA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of nisin (0 or 300 IU), Ethylenediamine Tetraacetic Acid (EDTA, 20 mM) and (nisin 300 IU+ EDTA 20 mM) on growth parameters; including lag period (LP) and growth rate (GR) of Escherichia coli O157:H7, L. monocytogenes and Salmonella spp. in the presence or absence of aerobic mesophilic bac...

  7. Microbiological Quality of Ready-to-Eat Vegetables Collected in Mexico City: Occurrence of Aerobic-Mesophilic Bacteria, Fecal Coliforms, and Potentially Pathogenic Nontuberculous Mycobacteria

    PubMed Central

    Cerna-Cortes, Jorge Francisco; Leon-Montes, Nancy; Cortes-Cueto, Ana Laura; Salas-Rangel, Laura P.; Helguera-Repetto, Addy Cecilia; Lopez-Hernandez, Daniel; Rivera-Gutierrez, Sandra; Fernandez-Rendon, Elizabeth; Gonzalez-y-Merchand, Jorge Alberto

    2015-01-01

    The aims of this study were to evaluate the microbiological quality and the occurrence of nontuberculous mycobacteria (NTM) in a variety of salads and sprouts from supermarkets and street vendors in Mexico City. Aerobic-mesophilic bacteria (AMB) were present in 100% of RTE-salads samples; 59% of samples were outside guidelines range (>5.17 log10 CFU per g). Although fecal coliforms (FC) were present in 32% of samples, only 8% of them exceeded the permissible limit (100?MPN/g). Regarding the 100 RTE-sprouts, all samples were also positive for AMB and total coliforms (TC) and 69% for FC. Seven NTM species were recovered from 7 salad samples; they included three M. fortuitum, two M. chelonae, one M. mucogenicum, and one M. sp. Twelve RTE-sprouts samples harbored NTM, which were identified as M. porcinum (five), M. abscessus (two), M. gordonae (two), M. mucogenicum (two), and M. avium complex (one). Most RTE-salads and RTE-sprouts had unsatisfactory microbiological quality and some harbored NTM associated with illness. No correlation between the presence of coliforms and NTM was found. Overall, these results suggest that RTE-salads and RTE-sprouts might function as vehicles for NTM transmission in humans; hence, proper handling and treatment before consumption of such products might be recommendable. PMID:25918721

  8. Fate of mesophilic aerobic bacteria and Salmonella enterica on the surface of eggs as affected by chicken feces, storage temperature, and relative humidity.

    PubMed

    Park, Sunhyung; Choi, Seonyeong; Kim, Hoikyung; Kim, Yoonsook; Kim, Byeong-sam; Beuchat, Larry R; Ryu, Jee-Hoon

    2015-06-01

    We compared the microbiological quality of chicken eggshells obtained from a traditional wholesale market and a modern supermarket. We also determined the survival and growth characteristics of naturally occurring mesophilic aerobic bacteria (MAB) and artificially inoculated Salmonella enterica on eggshells under various environmental conditions (presence of chicken feces, temperature [4, 12, or 25 °C], and relative humidity [RH; 43 or 85%]). The populations of MAB, coliforms, and molds and yeasts on eggshells purchased from a traditional wholesale market were significantly (P ? 0.05) higher than those from a modern supermarket. In the second study, when we stored uninoculated eggs under various storage conditions, the population of MAB on eggshells (4.7-4.9 log CFU/egg) remained constant for 21 days, regardless of storage conditions. However, when eggshells were inoculated with S. enterica and stored under the same conditions, populations of the pathogen decreased significantly (P ? 0.05) under all tested conditions. Survival of S. enterica increased significantly (P ? 0.05) in the presence of feces, at low temperatures, and at low RH. These observations will be of value when predicting the behavior of microorganisms on eggshells and selecting storage conditions that reduce the populations of S. enterica on eggshells during distribution. PMID:25791009

  9. Effect of hot water spray on broiler carcasses for reduction of loosely attached, intermediately attached, and tightly attached pathogenic (Salmonella and Campylobacter) and mesophilic aerobic bacteria.

    PubMed

    Zhang, L; Singh, P; Lee, H C; Kang, I

    2013-03-01

    Chickens are known to harbor many bacteria, including pathogenic microorganisms such as Salmonella and Campylobacter. The objective of this study was to evaluate the efficacy of hot water spray (HWS, 71°C for 1 min) in reducing bacterial contamination of prechilled broiler carcasses. For each of 4 replications, skin samples from 5 broilers were collected at 3 processing stages: after bleeding (feathers removed manually), after evisceration (with/without HWS), and after water chilling. Broiler skin was quantitatively assessed for loosely attached (by rinsing the skin), intermediately attached (by stomaching the rinsed skin), and tightly attached (by grinding the rinsed/stomached skin) mesophilic aerobic bacteria (MAB) and Campylobacter as well as for the prevalence of Salmonella and Campylobacter. Broiler skins possessed 6.4 to 6.6 log cfu/g, 3.8 to 4.1 log cfu/g, and 2.8 to 3.5 log cfu/g of MAB populations after bleeding, evisceration, and chilling, respectively. The HWS resulted in more than 1 log unit of reduction in MAB immediately after evisceration and immediately after chilling regardless of microbial sampling method. Compared with MAB, the contamination of Campylobacter was low (1.7 to 2.6 log cfu/g) after bleeding, but the level was not reduced throughout the processing steps regardless of HWS. The application of HWS reduced the prevalence of Salmonella after chilling, but not for Campylobacter except for loosely attached cells. After hot water exposure, a partially cooked appearance was seen on both broiler skin and skinless breast surface. More research is required to effectively eliminate pathogenic organisms during processing and suppress any recovery of bacteria regardless of attachment type after chilling. PMID:23436532

  10. Comprehensive microbial analysis of combined mesophilic anaerobic-thermophilic aerobic process treating high-strength food wastewater.

    PubMed

    Jang, Hyun Min; Ha, Jeong Hyub; Park, Jong Moon; Kim, Mi-Sun; Sommer, Sven G

    2015-04-15

    A combined mesophilic anaerobic-thermophilic aerobic process was used to treat high-strength food wastewater in this study. During the experimental period, most of solid residue from the mesophilic anaerobic reactor (R1) was separated by centrifugation and introduced into the thermophilic aerobic reactor (R2) for further digestion. Then, thermophilic aerobically-digested sludge was reintroduced into R1 to enhance reactor performance. The combined process was operated with two different Runs: Run I with hydraulic retention time (HRT) = 40 d (corresponding OLR = 3.5 kg COD/m(3) d) and Run II with HRT = 20 d (corresponding OLR = 7 kg COD/m(3)). For a comparison, a single-stage mesophilic anaerobic reactor (R3) was operated concurrently with same OLRs and HRTs as the combined process. During the overall digestion, all reactors showed high stability without pH control. The combined process demonstrated significantly higher organic matter removal efficiencies (over 90%) of TS, VS and COD and methane production than did R3. Quantitative real-time PCR (qPCR) results indicated that higher populations of both bacteria and archaea were maintained in R1 than in R3. Pyrosequencing analysis revealed relatively high abundance of phylum Actinobacteria in both R1 and R2, and a predominance of phyla Synergistetes and Firmicutes in R3 during Run II. Furthermore, R1 and R2 shared genera (Prevotella, Aminobacterium, Geobacillus and Unclassified Actinobacteria), which suggests synergy between mesophilic anaerobic digestion and thermophilic aerobic digestion. For archaea, in R1 methanogenic archaea shifted from genus Methanosaeta to Methanosarcina, whereas genera Methanosaeta, Methanobacterium and Methanoculleus were predominant in R3. The results demonstrated dynamics of key microbial populations that were highly consistent with an enhanced reactor performance of the combined process. PMID:25689817

  11. DESTRUCTION BY ANAEROBIC MESOPHILIC AND THERMOPHILIC DIGESTION OF VIRUSES AND INDICATOR BACTERIA INDIGENOUS TO DOMESTIC SLUDGES

    EPA Science Inventory

    In raw sludges and in mesophilically and thermophilically digested anaerobic sludges, large variations in numbers of viruses occurred over narrow ranges of numbers of fecal coliforms, total coliforms, and fecal streptococci, demonstrating that the bacteria are poor quantitative r...

  12. Technical note: enumeration of mesophilic aerobes in milk: evaluation of standard official protocols and Petrifilm aerobic count plates.

    PubMed

    Freitas, R; Nero, L A; Carvalho, A F

    2009-07-01

    Enumeration of mesophilic aerobes (MA) is the main quality and hygiene parameter for raw and pasteurized milk. High levels of these microorganisms indicate poor conditions in production, storage, and processing of milk, and also the presence of pathogens. Fifteen raw and 15 pasteurized milk samples were submitted for MA enumeration by a conventional plating method (using plate count agar) and Petrifilm Aerobic Count plates (3M, St. Paul, MN), followed by incubation according to 3 official protocols: IDF/ISO (incubation at 30 degrees C for 72 h), American Public Health Association (32 degrees C for 48 h), and Brazilian Ministry of Agriculture (36 degrees C for 48 h). The results were compared by linear regression and ANOVA. Considering the results from conventional methodology, good correlation indices and absence of significant differences between mean counts were observed, independent of type of milk sample (raw or pasteurized) and incubation conditions (IDF/ISO, American Public Health Association, or Ministry of Agriculture). Considering the results from Petrifilm Aerobic Count plates, good correlation indices and absence of significant differences were only observed for raw milk samples. The microbiota of pasteurized milk interfered negatively with the performance of Petrifilm Aerobic Count plates, probably because of the presence of microorganisms that poorly reduce the dye indicator of this system. PMID:19528584

  13. Comparison of Petrifilm method to conventional methods for enumerating aerobic bacteria, coliforms, Escherichia coli and yeasts and molds in foods.

    PubMed

    Jordano, R; Lopez, C; Rodriguez, V; Cordoba, G; Medina, L M; Barrios, J

    1995-01-01

    The Petrifilm plates method was compared to conventional methods (PCA, VRBA, Levine EMB agar and OGYE agar) for enumeration of mesophilic aerobic bacteria, coliforms, Escherichia coli, and yeasts+molds in six homogeneous lots of different food groups (pasteurized milk, yoghurt ice cream, eggs, minced meat, fresh strawberries and frozen green beans). For all the microbiological criteria except for yeasts and molds and mesophilic aerobic bacteria in frozen green beans, the mean values of counts with Petrifilm plates were higher than those obtained with traditional methods. The correlation coefficient of Petrifilm aerobic bacteria, coliforms, and yeasts + molds v. PCA, VRBA and OGYE agar for each microbiological criterion for a composite of six food products were 0.897, 0.861 and 0.981, respectively. PMID:8548198

  14. Comparison of sludge digestion under aerobic and anaerobic conditions with a focus on the degradation of proteins at mesophilic temperature.

    PubMed

    Shao, Liming; Wang, Tianfeng; Li, Tianshui; Lü, Fan; He, Pinjing

    2013-07-01

    Aerobic and anaerobic digestion are popular methods for the treatment of waste activated sludge. However, the differences in degradation of sludge during aerobic and anaerobic digestion remain unclear. In this study, the sludge degradation during aerobic and anaerobic digestion was investigated at mesophilic temperature, focused on protein based on the degradation efficiency and degree of humification. The duration of aerobic and anaerobic digestion was about 90 days. The final degradation efficiency of volatile solid was 66.1 ± 1.6% and 66.4 ± 2.4% under aerobic and anaerobic conditions, respectively. The final degradation efficiency of protein was 67.5 ± 1.4% and 65.1 ± 2.6% under aerobic and anaerobic conditions, respectively. The degradation models of volatile solids were consistent with those of protein under both aerobic and anaerobic conditions. The solubility of protein under aerobic digestion was greater than that under anaerobic digestion. Moreover, the humification index of dissolved organic matter of aerobic digestion was greater than that during anaerobic digestion. PMID:23685650

  15. Biology of Moderately Halophilic Aerobic Bacteria

    PubMed Central

    Ventosa, Antonio; Nieto, Joaquín J.; Oren, Aharon

    1998-01-01

    The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms of adjustment of the intracellular environments and the properties of the cytoplasmic membrane enable rapid adaptation to changes in the salt concentration of the environment. Approaches to the study of genetic processes have recently been developed for several moderate halophiles, opening the way toward an understanding of haloadaptation at the molecular level. The new information obtained is also expected to contribute to the development of novel biotechnological uses for these organisms. PMID:9618450

  16. The aerobic activity of metronidazole against anaerobic bacteria.

    PubMed

    Dione, Niokhor; Khelaifia, Saber; Lagier, Jean-Christophe; Raoult, Didier

    2015-05-01

    Recently, the aerobic growth of strictly anaerobic bacteria was demonstrated using antioxidants. Metronidazole is frequently used to treat infections caused by anaerobic bacteria; however, to date its antibacterial activity was only tested in anaerobic conditions. Here we aerobically tested using antioxidants the in vitro activities of metronidazole, gentamicin, doxycycline and imipenem against 10 common anaerobic and aerobic bacteria. In vitro susceptibility testing was performed by the disk diffusion method, and minimum inhibitory concentrations (MICs) were determined by Etest. Aerobic culture of the bacteria was performed at 37°C using Schaedler agar medium supplemented with 1mg/mL ascorbic acid and 0.1mg/mL glutathione; the pH was adjusted to 7.2 by 10M KOH. Growth of anaerobic bacteria cultured aerobically using antioxidants was inhibited by metronidazole after 72h of incubation at 37°C, with a mean inhibition diameter of 37.76mm and an MIC of 1?g/mL; however, strains remained non-sensitive to gentamicin. No growth inhibition of aerobic bacteria was observed after 24h of incubation at 37°C with metronidazole; however, inhibition was observed with doxycycline and imipenem used as controls. These results indicate that bacterial sensitivity to metronidazole is not related to the oxygen tension but is a result of the sensitivity of the micro-organism. In future, both culture and antibiotic susceptibility testing of strictly anaerobic bacteria will be performed in an aerobic atmosphere using antioxidants in clinical microbiology laboratories. PMID:25813393

  17. Previously unclassified bacteria dominate during thermophilic and mesophilic anaerobic pre-treatment of primary sludge.

    PubMed

    Pervin, Hasina M; Batstone, Damien J; Bond, Philip L

    2013-06-01

    Thermophilic biological pre-treatment enables enhanced anaerobic digestion for treatment of wastewater sludges but, at present, there is limited understanding of the hydrolytic-acidogenic microbial composition and its contribution to this process. In this study, the process was assessed by comparing the microbiology of thermophilic (50-65 °C) and mesophilic (35 °C) pre-treatment reactors treating primary sludge. A full-cycle approach for the 16S rRNA genes was applied in order to monitor the diversity of bacteria and their abundance in a thermophilic pre-treatment reactor treating primary sludge. For the thermophilic pre-treatment (TP), over 90% of the sequences were previously undetected and these had less than 97% sequence similarity to cultured organisms. During the first 83 days, members of the Betaproteobacteria dominated the community sequences and a newly designed probe was used to monitor a previously unknown bacterium affiliated with the genus Brachymonas. Between days 85 and 183, three phylotypes that affiliated with the genera Comamonas, Clostridium and Lysobacter were persistently dominant in the TP community, as revealed by terminal-restriction fragment length polymorphism (T-RFLP). Hydrolytic and fermentative functions have been speculated for these bacteria. Mesophilic pre-treatment (MP) and TP communities were different but they were both relatively dynamic. Statistical correlation analysis and the function of closely allied reference organisms indicated that previously unclassified bacteria dominated the TP community and may have been functionally involved in the enhanced hydrolytic performance of thermophilic anaerobic pre-treatment. This study is the first to reveal the diversity and dynamics of bacteria during anaerobic digestion of primary sludge. PMID:23643091

  18. Aerobic uranium (VI) bioprecipitation by metal-resistant bacteria isolated from radionuclide-

    E-print Network

    Skolnick, Jeff

    Aerobic uranium (VI) bioprecipitation by metal-resistant bacteria isolated from radionuclide of constitutive phosphatase activity were subsequently tested in U(VI) bioprecipitation assays. When aerobically requires anaerobic con- ditions, biomineralization can occur aerobically, making this process a possible

  19. Characterization of aerobic spore-forming bacteria associated with industrial dairy processing environments and product spoilage.

    PubMed

    Lücking, Genia; Stoeckel, Marina; Atamer, Zeynep; Hinrichs, Jörg; Ehling-Schulz, Monika

    2013-09-01

    Due to changes in the design of industrial food processing and increasing international trade, highly thermoresistant spore-forming bacteria are an emerging problem in food production. Minimally processed foods and products with extended shelf life, such as milk products, are at special risk for contamination and subsequent product damages, but information about origin and food quality related properties of highly heat-resistant spore-formers is still limited. Therefore, the aim of this study was to determine the biodiversity, heat resistance, and food quality and safety affecting characteristics of aerobic spore-formers in the dairy sector. Thus, a comprehensive panel of strains (n=467), which originated from dairy processing environments, raw materials and processed foods, was compiled. The set included isolates associated with recent food spoilage cases and product damages as well as isolates not linked to product spoilage. Identification of the isolates by means of Fourier-transform infrared spectroscopy and molecular methods revealed a large biodiversity of spore-formers, especially among the spoilage associated isolates. These could be assigned to 43 species, representing 11 genera, with Bacillus cereus s.l. and Bacillus licheniformis being predominant. A screening for isolates forming thermoresistant spores (TRS, surviving 100°C, 20 min) showed that about one third of the tested spore-formers was heat-resistant, with Bacillus subtilis and Geobacillus stearothermophilus being the prevalent species. Strains producing highly thermoresistant spores (HTRS, surviving 125°C, 30 min) were found among mesophilic as well as among thermophilic species. B. subtilis and Bacillus amyloliquefaciens were dominating the group of mesophilic HTRS, while Bacillus smithii and Geobacillus pallidus were dominating the group of thermophilic HTRS. Analysis of spoilage-related enzymes of the TRS isolates showed that mesophilic strains, belonging to the B. subtilis and B. cereus groups, were strongly proteolytic, whereas thermophilic strains displayed generally a low enzymatic activity and thus spoilage potential. Cytotoxicity was only detected in B. cereus, suggesting that the risk of food poisoning by aerobic, thermoresistant spore-formers outside of the B. cereus group is rather low. PMID:23973839

  20. Metabolic and genetic diversity of mesophilic and thermophilic bacteria isolated from composted municipal sludge on poly-epsilon-caprolactones.

    PubMed

    Tiago, Igor; Teixeira, Isabel; Silva, Sílvia; Chung, Paula; Veríssimo, António; Manaia, Célia M

    2004-12-01

    Thirty mesophilic and thermophilic bacteria were isolated from thermobiotically digested sewage sludge in culture medium supplemented with poly-epsilon-caprolactone (PCL). The ability of each purified isolate to degrade PCL and to produce polymer-degrading extracellular enzymes was assessed. Isolates were characterized based on random amplified polymorphic DNA (RAPD), 16S rDNA sequence-based phylogenetic affiliation and carbohydrate-based nutritional versatility. Mesophilic isolates with ability to degrade PCL were attributed to the genera Acinetobacter, Burkholderia, Pseudomonas, and Staphylococcus. Thermophilic isolates were members of the genus Bacillus. Despite the restricted phylogenetic and genotypic diversity observed for thermophiles, their metabolic versatility and wide range of growth temperatures suggest an important activity of these organisms during the whole composting process. PMID:15696616

  1. Use of mesophilic and thermophilic bacteria for the improvement of copper extraction from a low-grade ore

    NASA Astrophysics Data System (ADS)

    Darezereshki, E.; Schaffie, M.; Lotfalian, M.; Seiedbaghery, S. A.; Ranjbar, M.

    2011-04-01

    Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.

  2. Survival of multidrug-resistant bacteria in thermophilic and mesophilic anaerobic co-digestion of dairy manure and waste milk.

    PubMed

    Beneragama, Nilmini; Iwasaki, Masahiro; Lateef, Suraju A; Yamashiro, Takaki; Ihara, Ikko; Umetsu, Kazutaka

    2013-05-01

    Anaerobic digestion is considered as a promising method to manage animal waste with antibiotic-resistant bacteria. Current research was conducted to investigate the survival of multidrug-resistant bacteria (MDRB) resistant to three groups of antibiotics: (i) cefazolin, neomycin, vancomycin, kanamycin (group 1); (ii) penicillin, oxytetracycline, ampicillin, streptomycin (group 2); and (iii) cefazolin, neomycin, vancomycin, kanamycin, penicillin, oxytetracycline, ampicillin, streptomycin (group 3), in anaerobic digestion of dairy manure and co-digestion of dairy manure and waste milk at 37°C and 55°C for 22 days, respectively. The population densities of three groups of MDRB on peptone, tryptone, yeast and glucose agar plates incubated at 30°C for 7 days before and after digestion showed 100% destruction in both digestates at thermophilic temperature. Overall reduction of more than 90% of three groups of MDRB was observed in mesophilic digestion with no significant differences (P?>?0.05) between manure and milk mixture. Co-digestion of dairy manure and waste milk always produced significantly (P?mesophilic digestion. The results demonstrate that thermophilic co-digestion of dairy manure and waste milk offers more benefits in terms of the environment and economy. PMID:23607603

  3. Aerobic salivary bacteria in wild and captive Komodo dragons.

    PubMed

    Montgomery, Joel M; Gillespie, Don; Sastrawan, Putra; Fredeking, Terry M; Stewart, George L

    2002-07-01

    During the months of November 1996, August 1997, and March 1998, saliva and plasma samples were collected for isolation of aerobic bacteria from 26 wild and 13 captive Komodo dragons (Varanus komodoensis). Twenty-eight Gram-negative and 29 Gram-positive species of bacteria were isolated from the saliva of the 39 Komodo dragons. A greater number of wild than captive dragons were positive for both Gram-negative and Gram-positive bacteria. The average number of bacterial species within the saliva of wild dragons was 46% greater than for captive dragons. While Escherichia coli was the most common bacterium isolated from the saliva of wild dragons, this species was not present in captive dragons. The most common bacteria isolated from the saliva of captive dragons were Staphylococcus capitis and Staphylococcus capitis and Staphylococcus caseolyticus, neither of which were found in wild dragons. High mortality was seen among mice injected with saliva from wild dragons and the only bacterium isolated from the blood of dying mice was Pasteurella multocida. A competitive inhibition enzyme-linked immunosorbent assay revealed the presence of anti-Pasteurella antibody in the plasma of Komodo dragons. Four species of bacteria isolated from dragon saliva showed resistance to one or more of 16 antimicrobics tested. The wide variety of bacteria demonstrated in the saliva of the Komodo dragon in this study, at least one species of which was highly lethal in mice and 54 species of which are known pathogens, support the observation that wounds inflicted by this animal are often associated with sepsis and subsequent bacteremia in prey animals. PMID:12238371

  4. The survival of cefazolin-resistant bacteria in mesophilic co-digestion of dairy manure and waste milk.

    PubMed

    Beneragama, Nilmini; Moriya, Yusuke; Yamashiro, Takaki; Iwasaki, Masahiro; Lateef, Suraju A; Ying, Chun; Umetsu, Kazutaka

    2013-08-01

    The use of cefazolin to treat mastitic cows leads to cefazolin residues in milk and manure. This is responsible for the high occurrence of cefazolin resistant bacteria (CRB) in waste and the environment. Anaerobic digestion is considered to have the potential to reduce antibiotic-resistant bacteria present in waste that results from concentrated animal feeding operations. Thus, the objective of this study was to investigate the survival of CRB and the digester performance in mesophilic co-digestion of dairy manure and waste milk. The experiment was carried out using three digester compositions: 100% slurry (slurry), 50% slurry + 50% manure (manure mixture) and 50% slurry + 45% manure + 5% waste milk (milk mixture) in batch digesters of 1 l with a working volume of 800 ml in triplicate at 37°C for 34 days. The daily biogas production in each digester, and methane (CH4) and carbon dioxide compositions in the gas were determined. The population densities of total culturable bacteria (TCB) and CRB were determined by plate counts on agar media at day 0, 10, 20 and 34 of digestion. Milk mixture produced the highest (P < 0.05) daily and cumulative total and CH4 gas. The maximum percentage reductions of TCB and CRB in manure and milk mixture was observed at day 20, the values being 96.2%, 96.0% and 99.8% and 99.8% respectively. Final volatile fatty acids (VFA) and pH values of the digesters confirmed the digester stability. Based on the findings, mesophilic anaerobic digestion can be considered a potent method to avoid the dissemination of CRB in nature. PMID:23512952

  5. Mesophilic and Psychrotrophic Bacteria from Meat and Their Spoilage Potential In Vitro and in Beef ?

    PubMed Central

    Ercolini, Danilo; Russo, Federica; Nasi, Antonella; Ferranti, Pasquale; Villani, Francesco

    2009-01-01

    Mesophilic and psychrotrophic populations from refrigerated meat were identified in this study, and the spoilage potential of microbial isolates in packaged beef was evaluated by analyzing the release of volatile organic compounds (VOC) by gas chromatography-mass spectrometry (GC/MS). Fifty mesophilic and twenty-nine psychrotrophic isolates were analyzed by random amplified polymorphic DNA-PCR, and representative strains were identified by 16S rRNA gene sequencing. Carnobacterium maltaromaticum and C. divergens were the species most frequently found in both mesophilic and psychrotrophic populations. Acinetobacter baumannii, Buttiauxella spp. and Serratia spp. were identified among the mesophilic isolates, while Pseudomonas spp. were commonly identified among the psychrotrophs. The isolates were further characterized for their growth at different temperatures and their proteolytic activity in vitro on meat proteins extracts at 7°C. Selected proteolytic strains of Serratia proteamaculans, Pseudomonas fragi, and C. maltaromaticum were used to examine their spoilage potential in situ. Single strains of these species and mixtures of these strains were used to contaminate beef chops that were packed and stored at 7°C. At time intervals up to 1 month, viable counts were determined, and VOC were identified by GC/MS. Generally, the VOC concentrations went to increase during the storage of the contaminated meats, and the profiles of the analyzed meat changed dramatically depending on the contaminating microbial species. About 100 volatiles were identified in the different contaminated samples. Among the detected volatiles, some specific molecules were identified only when the meat was contaminated by a specific microbial species. Compounds such as 2-ethyl-1-hexanol, 2-buten-1-ol, 2-hexyl-1-octanol, 2-nonanone, and 2-ethylhexanal were detectable only for C. maltaromaticum, which also produced the highest number of aldehydes, lactones, and sulfur compounds. The highest number of alcohols and ketons were detected in the headspace of meat samples contaminated by P. fragi, whereas the highest concentrations of some alcohols, such as 1-octen-3-ol, and some esters, such as isoamyl acetate, were produced by S. proteamaculans. In conclusion, different microbial species can contribute to meat spoilage with release of different volatile compounds that concur to the overall quality decrease of spoiling meat. PMID:19201980

  6. Precipitation of Dolomite in Aerobic Culture Experiments Using Halophilic Bacteria

    NASA Astrophysics Data System (ADS)

    Roman, M. S.; Vasconcelos, C.; McKenzie, J. A.

    2003-12-01

    The study of carbonate biomineralization in hypersaline environments provides information about the key role microorganisms have played in global carbon cycling, especially in the Precambrian. Recently, a microbial dolomite model was proposed based on the study of a hypersaline coastal lagoon, Lagoa Vermelha, Rio de Janeiro (Brazil). This model suggests that sulfate-reducing bacteria mediate dolomite precipitation by increasing pH and removing the sulfate inhibitor. The anoxic conditions of this system may not, however, apply to all ancient dolomite formation. Dolomite is an abundant carbonate mineral found widespread in the geological record in a variety of environmental settings. Thus, a single microbial dolomite model probably cannot explain its widespread distribution and a broad spectrum of conditions may be linked with its formation. In contrast to Lagoa Vermelha, Brejo do Espinho, a shallow hypersaline lagoon located in the same region, is a dolomite-forming environment with oxic bottom conditions. The sediment comprises primarily high Mg-calcite and Ca-dolomite. Heterotrophic microorganisms have been isolated from algal mats growing in Brejo do Espinho, and biomineralization experiments have been conducted at variable temperatures (15, 20, 25, 30, 35 and 40° C) and salinities (sea water and 2x seawater) to simulate the natural environmental conditions. After a 20-day incubation period, several aerobic culture experiments have crystal growth of Ca-dolomite and high Mg-calcite. Our study demonstrates that, under aerobic conditions, heterotrophic microorganisms can mediate dolomite precipitation. These results indicate that microbial dolomite precipitation is not necessarily linked to any particular group of organisms or specific metabolic processes or even a specific environment, i.e., it is not exclusively an anoxic mineral but can be precipitated in the presence of oxygen. This has implications for the distribution of dolomite in the geologic record.

  7. Evaluation of the petrifilm aerobic count plate for enumeration of aerobic marine bacteria from seawater and Caulerpa lentillifera.

    PubMed

    Kudaka, Jun; Horii, Toru; Tamanaha, Koji; Itokazu, Kiyomasa; Nakamura, Masaji; Taira, Katsuya; Nidaira, Minoru; Okano, Sho; Kitahara, Akio

    2010-08-01

    The enumeration and evaluation of the activity of marine bacteria are important in the food industry. However, detection of marine bacteria in seawater or seafood has not been easy. The Petrifilm aerobic count plate (ACP) is a ready-to-use alternative to the traditional enumeration media used for bacteria associated with food. The purpose of this study was to evaluate the usefulness of a simple detection and enumeration method utilizing the Petrifilm ACP for enumeration of aerobic marine bacteria from seawater and an edible seaweed, Caulerpa lentillifera. The efficiency of enumeration of total aerobic marine bacteria on Petrifilm ACP was compared with that using the spread plate method on marine agar with 80 seawater and 64 C. lentillifera samples. With sterile seawater as the diluent, a close correlation was observed between the method utilizing Petrifilm ACP and that utilizing the conventional marine agar (r=0.98 for seawater and 0.91 for C. lentillifera). The Petrifilm ACP method was simpler and less time-consuming than the conventional method. These results indicate that Petrifilm ACP is a suitable alternative to conventional marine agar for enumeration of marine microorganisms in seawater and C. lentillifera samples. PMID:20819367

  8. Influence of thermophilic aerobic digestion as a sludge pre-treatment and solids retention time of mesophilic anaerobic digestion on the methane production, sludge digestion and microbial communities in a sequential digestion process.

    PubMed

    Jang, Hyun Min; Cho, Hyun Uk; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

    2014-01-01

    In this study, the changes in sludge reduction, methane production and microbial community structures in a process involving two-stage thermophilic aerobic digestion (TAD) and mesophilic anaerobic digestion (MAD) under different solid retention times (SRTs) between 10 and 40 days were investigated. The TAD reactor (RTAD) was operated with a 1-day SRT and the MAD reactor (RMAD) was operated at three different SRTs: 39, 19 and 9 days. For a comparison, control MAD (RCONTROL) was operated at three different SRTs of 40, 20 and 10 days. Our results reveal that the sequential TAD-MAD process has about 42% higher methane production rate (MPR) and 15% higher TCOD removal than those of RCONTROL when the SRT decreased from 40 to 20 days. Denaturing gradient gel electrophoresis (DGGE) and real-time PCR results indicate that RMAD maintained a more diverse bacteria and archaea population compared to RCONTROL, due to the application of the biological TAD pre-treatment process. In RTAD, Ureibacillus thermophiles and Bacterium thermus were the major contributors to the increase in soluble organic matter. In contrast, Methanosaeta concilii, a strictly aceticlastic methanogen, showed the highest population during the operation of overall SRTs in RMAD. Interestingly, as the SRT decreased to 20 days, syntrophic VFA oxidizing bacteria, Clostridium ultunense sp., and a hydrogenotrophic methanogen, Methanobacterium beijingense were detected in RMAD and RCONTROL. Meanwhile, the proportion of archaea to total microbe in RMAD and RCONTROL shows highest values of 10.5 and 6.5% at 20-d SRT operation, respectively. Collectively, these results demonstrate that the increased COD removal and methane production at different SRTs in RMAD might be attributed to the increased synergism among microbial species by improving the hydrolysis of the rate limiting step in sludge with the help of the biological TAD pre-treatment. PMID:23871253

  9. Nitrososphaera viennensis gen. nov., sp. nov., an aerobic and mesophilic, ammonia-oxidizing archaeon from soil and a member of the archaeal phylum Thaumarchaeota

    PubMed Central

    Stieglmeier, Michaela; Klingl, Andreas; Alves, Ricardo J. E.; Rittmann, Simon K.-M. R.; Melcher, Michael; Leisch, Nikolaus

    2014-01-01

    A mesophilic, neutrophilic and aerobic, ammonia-oxidizing archaeon, strain EN76T, was isolated from garden soil in Vienna (Austria). Cells were irregular cocci with a diameter of 0.6–0.9 µm and possessed archaella and archaeal pili as cell appendages. Electron microscopy also indicated clearly discernible areas of high and low electron density, as well as tubule-like structures. Strain EN76T had an S-layer with p3 symmetry, so far only reported for members of the Sulfolobales. Crenarchaeol was the major core lipid. The organism gained energy by oxidizing ammonia to nitrite aerobically, thereby fixing CO2, but growth depended on the addition of small amounts of organic acids. The optimal growth temperature was 42 °C and the optimal pH was 7.5, with ammonium and pyruvate concentrations of 2.6 and 1 mM, respectively. The genome of strain EN76T had a DNA G+C content of 52.7 mol%. Phylogenetic analyses of 16S rRNA genes showed that strain EN76T is affiliated with the recently proposed phylum Thaumarchaeota, sharing 85?% 16S rRNA gene sequence identity with the closest cultivated relative ‘Candidatus Nitrosopumilus maritimus’ SCM1, a marine ammonia-oxidizing archaeon, and a maximum of 81?% 16S rRNA gene sequence identity with members of the phyla Crenarchaeota and Euryarchaeota and any of the other recently proposed phyla (e.g. ‘Korarchaeota’ and ‘Aigarchaeota’). We propose the name Nitrososphaera viennensis gen. nov., sp. nov. to accommodate strain EN76T. The type strain of Nitrososphaera viennensis is strain EN76T (?=?DSM 26422T?=?JMC 19564T). Additionally, we propose the family Nitrososphaeraceae fam. nov., the order Nitrososphaerales ord. nov. and the class Nitrososphaeria classis nov. PMID:24907263

  10. Antibiotic Susceptibility Pattern of Aerobic and Anaerobic Bacteria Isolated From Surgical Site Infection of Hospitalized Patients

    PubMed Central

    Akhi, Mohammad Taghi; Ghotaslou, Reza; Beheshtirouy, Samad; Asgharzadeh, Mohammad; Pirzadeh, Tahereh; Asghari, Babak; Alizadeh, Naser; Toloue Ostadgavahi, Ali; Sorayaei Somesaraei, Vida; Memar, Mohammad Yousef

    2015-01-01

    Background: Surgical Site Infections (SSIs) are infections of incision or deep tissue at operation sites. These infections prolong hospitalization, delay wound healing, and increase the overall cost and morbidity. Objectives: This study aimed to investigate anaerobic and aerobic bacteria prevalence in surgical site infections and determinate antibiotic susceptibility pattern in these isolates. Materials and Methods: One hundred SSIs specimens were obtained by needle aspiration from purulent material in depth of infected site. These specimens were cultured and incubated in both aerobic and anaerobic condition. For detection of antibiotic susceptibility pattern in aerobic and anaerobic bacteria, we used disk diffusion, agar dilution, and E-test methods. Results: A total of 194 bacterial strains were isolated from 100 samples of surgical sites. Predominant aerobic and facultative anaerobic bacteria isolated from these specimens were the members of Enterobacteriaceae family (66, 34.03%) followed by Pseudomonas aeruginosa (26, 13.4%), Staphylococcus aureus (24, 12.37%), Acinetobacter spp. (18, 9.28%), Enterococcus spp. (16, 8.24%), coagulase negative Staphylococcus spp. (14, 7.22%) and nonhemolytic streptococci (2, 1.03%). Bacteroides fragilis (26, 13.4%), and Clostridium perfringens (2, 1.03%) were isolated as anaerobic bacteria. The most resistant bacteria among anaerobic isolates were B. fragilis. All Gram-positive isolates were susceptible to vancomycin and linezolid while most of Enterobacteriaceae showed sensitivity to imipenem. Conclusions: Most SSIs specimens were polymicrobial and predominant anaerobic isolate was B. fragilis. Isolated aerobic and anaerobic strains showed high level of resistance to antibiotics. PMID:26421133

  11. Efficiency of autothermal thermophilic aerobic digestion and thermophilic anaerobic digestion of municipal wastewater sludge in removing Salmonella spp. and indicator bacteria.

    PubMed

    Zábranská, J; Dohányos, M; Jenícek, P; R?ziciková, H; Vránová, A

    2003-01-01

    The study is focused on the comparison of autothermal thermophilic aerobic digestion, thermophilic and mesophilic anaerobic digestion, based on long-term monitoring of all processes in full-scale wastewater treatment plants, with an emphasis on the efficiency in destroying pathogens. The hygienisation effect was evaluated as a removal of counts of indicator bacteria, thermotolerant coliforms and enterococci as CFU/g total sludge solids and a frequency of a positive Salmonella spp. detection. Both thermophilic technologies of municipal wastewater sludge stabilisation had the capability of producing sludge A biosolids suitable for agricultural land application when all operational parameters (mainly temperature, mixing and retention time) were stable and maintained at an appropriate level. PMID:12639021

  12. Variable carbon isotope fractionation expressed by aerobic CH4-oxidizing bacteria

    E-print Network

    Chu, Kung-Hui "Bella"

    Variable carbon isotope fractionation expressed by aerobic CH4-oxidizing bacteria Alexis S Engineering, Texas A&M University, College Station, TX 77843-3136, USA d Center for Isotope Geochemistry 2005; accepted in revised form 5 December 2005 Abstract Carbon isotope fractionation factors reported

  13. Testing for aerobic heterotrophic bacteria allows no prediction of contamination with potentially pathogenic bacteria in the output water of dental chair units

    PubMed Central

    Bristela, Margit; Skolka, Astrid; Schmid-Schwap, Martina; Piehslinger, Eva; Indra, Alexander; Wewalka, Günther; Stauffer, Fritz

    2012-01-01

    Background: Currently, to our knowledge, quality of output water of dental chair units is not covered by specific regulations in the European Union, and national recommendations are heterogeneous. In Germany, water used in dental chair units must follow drinking water quality. In the United States of America, testing for aerobic heterotrophic bacteria is recommended. The present study was performed to evaluate whether the counts of aerobic heterotrophic bacteria correlate with the presence of potentially pathogenic bacteria such as Legionella spp. or Pseudomonas aeruginosa. Methods: 71 samples were collected from 26 dental chair units with integrated disinfection device and 31 samples from 15 outlets of the water distribution pipework within the department were examined. Samples were tested for aerobic heterotrophic bacteria at 35°C and 22°C using different culture media and for Legionella spp. and for Pseudomonas aeruginosa. Additionally, strains of Legionella pneumophila serogroup 1 were typed with monoclonal antibodies and representative samples of Legionella pneumophila serogroup 1 were typed by sequence based typing. Results: Our results showed a correlation between different agars for aerobic heterotrophic bacteria but no correlation for the count of aerobic heterotrophic bacteria and the presence of Legionella spp. or Pseudomonas aeruginosa. Conclusion: Testing for aerobic heterotrophic bacteria in output water or water distribution pipework within the departments alone is without any value for predicting whether the water is contaminated with potentially pathogenic bacteria like Legionella spp. or Pseudomonas aeruginosa. PMID:22558046

  14. Evaluation of Petrifilm method for enumerating aerobic bacteria in Crottin goat cheese.

    PubMed

    de Sousa, G B; Tamagnini, L M; González, R D; Budde, C E

    2005-01-01

    The Petrifilm Aerobic Count Plate (ACP) developed by 3M laboratories, is a ready-to-use culture medium system, useful for the enumeration of aerobic bacteria in food. Petrifilm was compared with a standard method in several different food products with satisfactory results. However, many studies showed that bacterial counts in Petrifilm were significantly lower than those obtained with conventional methods in fermented food. The purpose of this study was to compare the Petrifilm method for enumerating aerobic bacteria with a conventional method (PCA) in Crottin goat's cheese. Thirty samples were used for the colony count. The mean count and standard deviation were 7.18 +/- 1.17 log CFU g(-1) on PCA and 7.11 +/- 1.05 log CFU g(-1) on Petrifilm. Analysis of variance revealed no significant differences between both methods (t = 1.33, P = 0.193). The Pearson correlation coefficient (0.971, P = 0.0001) indicated a strong linear relationship between the Petrifilm and the standard method. The results showed that Petrifilm is suitable and a convenient alternative to this standard method for the enumeration of aerobic flora in goat soft cheese. PMID:16502643

  15. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Revised

    NASA Technical Reports Server (NTRS)

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2005-01-01

    The abundance of aerobic anoxygenic phototrophic (AM) bacteria, cyanobacteria and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic but only 5% or less in the Pacific. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than Prochlorococcus and 10-folder higher than Synechococcus. In contrast, Prochlorococcus outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. Concentrations of bacteriochlorophyll a (BChl a) were low (approx.1%) compared to chlorophyll a. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, in shelf break water the pigment content of AAP bacteria approached that of Prochlorococcus. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP genera (Erythrobacter and Roseobacter spp.). The distribution of AAP bacteria in the water column, which was similar in the Atlantic and the Pacific, was consistent with phototrophy.

  16. High abundances of aerobic anoxygenic photosynthetic bacteria in the South Pacific Ocean.

    PubMed

    Lami, Raphaël; Cottrell, Matthew T; Ras, Joséphine; Ulloa, Osvaldo; Obernosterer, Ingrid; Claustre, Hervé; Kirchman, David L; Lebaron, Philippe

    2007-07-01

    Little is known about the abundance, distribution, and ecology of aerobic anoxygenic phototrophic (AAP) bacteria, particularly in oligotrophic environments, which represent 60% of the ocean. We investigated the abundance of AAP bacteria across the South Pacific Ocean, including the center of the gyre, the most oligotrophic water body of the world ocean. AAP bacteria, Prochlorococcus, and total prokaryotic abundances, as well as bacteriochlorophyll a (BChl a) and divinyl-chlorophyll a concentrations, were measured at several depths in the photic zone along a gradient of oligotrophic conditions. The abundances of AAP bacteria and Prochlorococcus were high, together accounting for up to 58% of the total prokaryotic community. The abundance of AAP bacteria alone was up to 1.94 x 10(5) cells ml(-1) and as high as 24% of the overall community. These measurements were consistent with the high BChl a concentrations (up to 3.32 x 10(-3) microg liter(-1)) found at all stations. However, the BChl a content per AAP bacterial cell was low, suggesting that AAP bacteria are mostly heterotrophic organisms. Interestingly, the biovolume and therefore biomass of AAP bacteria was on average twofold higher than that of other prokaryotic cells. This study demonstrates that AAP bacteria can be abundant in various oligotrophic conditions, including the most oligotrophic regime of the world ocean, and can account for a large part of the bacterioplanktonic carbon stock. PMID:17496136

  17. Antibiotic resistance profiles among mesophilic aerobic bacteria in Nigerian chicken litter and associated antibiotic resistance genes1.

    PubMed

    Olonitola, Olayeni Stephen; Fahrenfeld, Nicole; Pruden, Amy

    2015-05-01

    The effect of global antibiotic use practices in livestock on the emergence of antibiotic resistant pathogens is poorly understood. There is a paucity of data among African nations, which suffer from high rates of antibiotic resistant infections among the human population. Escherichia (29.5%), Staphylococcus (15.8%), and Proteus (15.79%) were the dominant bacterial genera isolated from chicken litter from four different farms in Zaria, Nigeria, all of which contain human pathogenic members. Escherichia isolates were uniformly susceptible to augmentin and cefuroxime, but resistant to sulfamethoxazole (54.5%), ampicillin (22.7%), ciprofloxacin (18.2%), cephalothin (13.6%) and gentamicin (13.6%). Staphylococcus isolates were susceptible to ciprofloxacin, gentamicin, and sulfamethoxazole, but resistant to tetracycline (86.7%), erythromycin (80%), clindamycin (60%), and penicillin (33.3%). Many of the isolates (65.4%) were resistant to multiple antibiotics, with a multiple antibiotic resistance index (MARI) ? 0.2. sul1, sul2, and vanA were the most commonly detected antibiotic resistance genes among the isolates. Chicken litter associated with antibiotic use and farming practices in Nigeria could be a public health concern given that the antibiotic resistant patterns among genera containing pathogens indicate the potential for antibiotic treatment failure. However, the MARI values were generally lower than reported for Escherichia coli from intensive poultry operations in industrial nations. PMID:25725076

  18. Fast-Growing, Aerobic, Heterotrophic Bacteria from the Rhizosphere of Young Sugar Beet Plants

    PubMed Central

    Lambert, Bart; Meire, Patrick; Joos, Henk; Lens, Pierre; Swings, Jean

    1990-01-01

    Fast-growing, aerobic, heterotrophic bacteria from the root surface of young sugar beet plants were inventoried. Isolation of the most abundant bacteria from the root surface of each of 1,100 plants between the second and tenth leaf stage yielded 5,600 isolates. These plants originated from different fields in Belgium and Spain. All isolates were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total cellular proteins. Comparison of protein fingerprints allowed us to inventory the bacteria of individual plants of different fields or leaf stages and to analyze the composition and variability of the rhizobacterial population of young sugar beet plants. Each field harbored a specific population of bacteria which showed a highly hierarchic structure. A small number of bacteria occurring frequently at high densities dominated in each field. The major bacteria were identified as Pseudomonas fluorescens, Xanthomonas maltophilia, Pseudomonas paucimobilis, and Phyllobacterium sp. The former three species showed a high genetic variability as they were represented by different protein fingerprint types on the same or different fields or leaf stages. Twinspan analysis and relative abundance plots showed that the structure and composition of the bacterial populations varied strongly over time. Pseudomonads were typically early colonizers which were later replaced by X. maltophilia or Phyllobacterium sp. Images PMID:16348342

  19. The effect of bacteria, enzymes and inulin on fermentation and aerobic stability of corn silage

    PubMed Central

    Peymanfar, S; Kermanshahi, RK

    2012-01-01

    Background and Objectives Ensiling is a conservation method for forage crops. It is based on the fact that anaerobe lactic acid bacteria (LAB) convert watersoluble carbohydrates into organic acids. Therefore, pH decreases and the forage is preserved. The aim of this study was to isolate special kinds of lactic acid bacteria from silage and to study the effect of bacteria, inulin and enzymes as silage additives on the fermentation and aerobic stability of the silage. Materials and Methods The heterofermentative LAB were isolated from corn silages in Broujerd, Iran and biochemically characterized. Acid tolerance was studied by exposure to acidic PBS and growth in bile salt was measured by the spectrophotometric method. Results The results of molecular analysis using 16SrDNA sequences showed that the isolates belonged to Lactobacillus and Enterococcus genera. To enhance stability in acidic environment and against bile salts, microencapsulation with Alginate and Chitosan was used. The Lactobacillus plantarum strains were used as control. The inoculants (1 × 107 cfu/g) alone or in combination with inulin or in combination with enzymes were added to chopped forages and ensiled in 1.5-L anaerobic jars. Conclusion Combination of the isolates Lactobacillus and Enterococcus with inulin and enzymes can improve the aerobic stability of corn silage. PMID:23205249

  20. Aerobic Mercury-resistant bacteria alter Mercury speciation and retention in the Tagus Estuary (Portugal).

    PubMed

    Figueiredo, Neusa L; Canário, João; O'Driscoll, Nelson J; Duarte, Aida; Carvalho, Cristina

    2016-02-01

    Aerobic mercury-resistant bacteria were isolated from the sediments of two highly mercury-polluted areas of the Tagus Estuary (Barreiro and Cala do Norte) and one natural reserve area (Alcochete) in order to test their capacity to transform mercury. Bacterial species were identified using 16S rRNA amplification and sequencing techniques and the results indicate the prevalence of Bacillus sp. Resistance patterns to mercurial compounds were established by the determination of minimal inhibitory concentrations. Representative Hg-resistant bacteria were further tested for transformation pathways (reduction, volatilization and methylation) in cultures containing mercury chloride. Bacterial Hg-methylation was carried out by Vibrio fluvialis, Bacillus megaterium and Serratia marcescens that transformed 2-8% of total mercury into methylmercury in 48h. In addition, most of the HgR bacterial isolates showed Hg(2+)-reduction andHg(0)-volatilization resulting 6-50% mercury loss from the culture media. In summary, the results obtained under controlled laboratory conditions indicate that aerobic Hg-resistant bacteria from the Tagus Estuary significantly affect both the methylation and reduction of mercury and may have a dual face by providing a pathway for pollution dispersion while forming methylmercury, which is highly toxic for living organisms. PMID:26461264

  1. Quantification of syntrophic fatty acid-{beta}-oxidizing bacteria in a mesophilic biogas reactor by oligonucleotide probe hybridization

    SciTech Connect

    Hansen, K.H.; Ahring, B.K.; Raskin, L.

    1999-11-01

    Small-subunit rRNA sequences were obtained for two saturated fatty acid-{beta}-oxidizing syntrophic bacteria, Syntrophomonas sapovorans and Syntrophomonas wolfei LYB, and sequence analysis confirmed their classification as members of the family Syntrophomonadaceae. S.wolfei LYB was closely related to S.wolfei subsp. solfei, but S. sapovorans did not cluster with the other members of the genus Syntrophomonas. Five oligonucleotide probes targeting the small-subunit rRNA of different groups within the family Syntrophomonadaceae, which contains all currently known saturated fatty acid-{beta}-oxidizing syntrophic bacteria, were developed and characterized. The probes were designed to be specific at the family, genus, and species levels and were characterized by temperature-of-dissociation and specificity studies. To demonstrate the usefulness of the probes for the detection and quantification of saturated fatty acid-{beta}-oxidizing syntrophic bacteria in methanogenic environments, the microbial community structure of a sample from a full-scale biogas plant was determined. Hybridization results with probes for syntrophic bacteria and methanogens were compared to specific methanogenic activities and microbial numbers determined with most-probable-number estimates. Most of the methanogenic rRNA was comprised of Methanomicrobiales rRNA, suggesting that members of this order served as the main hydrogen-utilizing microorganisms. Between 0.2 and 1% of the rRNA was attributed to the Syntrophomonadaceae, or which the majority was accounted for by the genus Syntrophomonas.

  2. Constraints in the colonization of natural and engineered subterranean igneous rock aquifers by aerobic methane-oxidizing bacteria inferred by culture analysis.

    PubMed

    Chi Fru, E

    2008-08-01

    The aerobic methane-oxidizing bacteria (MOB) are suggested to be important for the removal of oxygen from subterranean aquifers that become oxygenated by natural and engineering processes. This is primarily because MOB are ubiquitous in the environment and in addition reduce oxygen efficiently. The biogeochemical factors that will control the success of the aerobic MOB in these kinds of underground aquifers remain unknown. In this study, viable and cultivable MOB occurring at natural and engineered deep granitic aquifers targeted for the disposal of spent nuclear fuel (SNF) in the Fennoscandian Shield (approximately 3-1000 m) were enumerated. The numbers were correlated with in situ salinity, methane concentrations, conductivity, pH, and depth. A mixed population habiting freshwater aquifers (approximately 3-20 m), a potential source for the inoculation of MOB into the deeper aquifers was tested for tolerance to NaCl, temperature, pH, and an ability to produce cysts and exospores. Extrapolations show that due to changing in situ parameters (salinity, conductivity, and pH), the numbers of MOB in the aquifers dropped quickly with depth. A positive correlation between the most probable numbers of MOB and methane concentrations was observed. Furthermore, the tolerance-based tests of cultured strains indicated that the MOB in the shallow aquifers thrived best in mesophilic and neutrophilic conditions as opposed to the hyperthermophilic and alkaliphilic conditions expected to develop in an engineered subterranean SNF repository. Overall, the survival of the MOB both quantitatively and physiologically in the granitic aquifers was under the strong influence of biogeochemical factors that are strongly depth-dependent. PMID:18462385

  3. Mono- and Dialkyl Glycerol Ether Lipids in Anaerobic Bacteria: Biosynthetic Insights from the Mesophilic Sulfate Reducer Desulfatibacillum alkenivorans PF2803T

    PubMed Central

    Mollex, Damien; Vinçon-Laugier, Arnauld; Hakil, Florence; Pacton, Muriel; Cravo-Laureau, Cristiana

    2015-01-01

    Bacterial glycerol ether lipids (alkylglycerols) have received increasing attention during the last decades, notably due to their potential role in cell resistance or adaptation to adverse environmental conditions. Major uncertainties remain, however, regarding the origin, biosynthesis, and modes of formation of these uncommon bacterial lipids. We report here the preponderance of monoalkyl- and dialkylglycerols (1-O-alkyl-, 2-O-alkyl-, and 1,2-O-dialkylglycerols) among the hydrolyzed lipids of the marine mesophilic sulfate-reducing proteobacterium Desulfatibacillum alkenivorans PF2803T grown on n-alkenes (pentadec-1-ene or hexadec-1-ene) as the sole carbon and energy source. Alkylglycerols account for one-third to two-thirds of the total cellular lipids (alkylglycerols plus acylglycerols), depending on the growth substrate, with dialkylglycerols contributing to one-fifth to two-fifths of the total ether lipids. The carbon chain distribution of the lipids of D. alkenivorans also depends on that of the substrate, but the chain length and methyl-branching patterns of fatty acids and monoalkyl- and dialkylglycerols are systematically congruent, supporting the idea of a biosynthetic link between the three classes of compounds. Vinyl ethers (1-alken-1?-yl-glycerols, known as plasmalogens) are not detected among the lipids of strain PF2803T. Cultures grown on different (per)deuterated n-alkene, n-alkanol, and n-fatty acid substrates further demonstrate that saturated alkylglycerols are not formed via the reduction of hypothetic alken-1?-yl intermediates. Our results support an unprecedented biosynthetic pathway to monoalkyl/monoacyl- and dialkylglycerols in anaerobic bacteria and suggest that n-alkyl compounds present in the environment can serve as the substrates for supplying the building blocks of ether phospholipids of heterotrophic bacteria. PMID:25724965

  4. Analyses of spatial distributions of sulfate-reducing bacteria and their activity in aerobic wastewater biofilms

    SciTech Connect

    Okabe, Satoshi; Itoh, Tsukasa; Satoh, Hisashi; Watanabe, Yoshimasa

    1999-11-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of O{sub 2}, H{sub 2}S, NO{sub 2}{minus}, NH{sub 2}{sup +}, and pH were measured with microelectrodes. In addition, a cross-evaluation of the FISH and microelectrode analyses was performed by comparing them with culture-based approaches and biogeochemical measurements. In situ hybridization revealed that a relatively high abundance of the probe SRB385-stained cells were evenly distributed throughout the biofilm, even in the toxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations. The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 {micro}m below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S{degree}) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms, which accounted for about 75% of the total S pool in the biofilm. The contribution of an internal Fe-sulfur cycle to the overall sulfur cycle in aerobic wastewater biofilms was insignificant (less than 1%) due to the relatively high sulfate reduction rate.

  5. Comparison between Rinse and Crush-and-Rub Sampling for Aerobic Bacteria Recovery from Hatching Eggs after Sanitization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compared surface and deep eggshell aerobic bacteria recovered by rinse and crush-and-rub sampling methods for commercial hatching eggs after treatments with sanitizers. Eggs were arranged into 5 treatments consisting of three sanitizers, Water, and No-treatment. Sanitizers were Hydrogen...

  6. Comparison between rinse and crush-and-rub sampling for aerobic bacteria recovery from broiler hatching eggs after sanitization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compared surface and deep eggshell aerobic bacteria recovered by rinse and crush-and-rub sampling methods for commercial hatching eggs after treatment with sanitizers. Eggs were arranged into 5 treatments consisting of No-treatment, Water, and three sanitizers. Sanitizers were Hydrogen ...

  7. Growth of aerobic ripening bacteria at the cheese surface is limited by the availability of iron.

    PubMed

    Monnet, Christophe; Back, Alexandre; Irlinger, Françoise

    2012-05-01

    The microflora on the surface of smear-ripened cheeses is composed of various species of bacteria and yeasts that contribute to the production of the desired organoleptic properties. The objective of the present study was to show that iron availability is a limiting factor in the growth of typical aerobic ripening bacteria in cheese. For that purpose, we investigated the effect of iron or siderophore addition in model cheeses that were coinoculated with a yeast and a ripening bacterium. Both iron and the siderophore desferrioxamine B stimulated the growth of ripening bacteria belonging to the genera Arthrobacter, Corynebacterium, and Brevibacterium. The extent of stimulation was strain dependent, and generally, the effect of desferrioxamine B was greater than that of iron. Measurements of the expression of genes related to the metabolism of iron by Arthrobacter arilaitensis Re117 by real-time reverse transcription-PCR showed that these genes were transcribed during growth in cheese. The addition of desferrioxamine B increased the expression of two genes encoding iron-siderophore ABC transport binding proteins. The addition of iron decreased the expression of siderophore biosynthesis genes and of part of the genes encoding iron-siderophore ABC transport components. It was concluded that iron availability is a limiting factor in the growth of typical cheese surface bacteria. The selection of strains with efficient iron acquisition systems may be useful for the development of defined-strain surface cultures. Furthermore, the importance of iron metabolism in the microbial ecology of cheeses should be investigated since it may result in positive or negative microbial interactions. PMID:22367081

  8. Diversity and Habitat Preferences of Cultivated and Uncultivated Aerobic Methanotrophic Bacteria Evaluated Based on pmoA as Molecular Marker.

    PubMed

    Knief, Claudia

    2015-01-01

    Methane-oxidizing bacteria are characterized by their capability to grow on methane as sole source of carbon and energy. Cultivation-dependent and -independent methods have revealed that this functional guild of bacteria comprises a substantial diversity of organisms. In particular the use of cultivation-independent methods targeting a subunit of the particulate methane monooxygenase (pmoA) as functional marker for the detection of aerobic methanotrophs has resulted in thousands of sequences representing "unknown methanotrophic bacteria." This limits data interpretation due to restricted information about these uncultured methanotrophs. A few groups of uncultivated methanotrophs are assumed to play important roles in methane oxidation in specific habitats, while the biology behind other sequence clusters remains still largely unknown. The discovery of evolutionary related monooxygenases in non-methanotrophic bacteria and of pmoA paralogs in methanotrophs requires that sequence clusters of uncultivated organisms have to be interpreted with care. This review article describes the present diversity of cultivated and uncultivated aerobic methanotrophic bacteria based on pmoA gene sequence diversity. It summarizes current knowledge about cultivated and major clusters of uncultivated methanotrophic bacteria and evaluates habitat specificity of these bacteria at different levels of taxonomic resolution. Habitat specificity exists for diverse lineages and at different taxonomic levels. Methanotrophic genera such as Methylocystis and Methylocaldum are identified as generalists, but they harbor habitat specific methanotrophs at species level. This finding implies that future studies should consider these diverging preferences at different taxonomic levels when analyzing methanotrophic communities. PMID:26696968

  9. Diversity and Habitat Preferences of Cultivated and Uncultivated Aerobic Methanotrophic Bacteria Evaluated Based on pmoA as Molecular Marker

    PubMed Central

    Knief, Claudia

    2015-01-01

    Methane-oxidizing bacteria are characterized by their capability to grow on methane as sole source of carbon and energy. Cultivation-dependent and -independent methods have revealed that this functional guild of bacteria comprises a substantial diversity of organisms. In particular the use of cultivation-independent methods targeting a subunit of the particulate methane monooxygenase (pmoA) as functional marker for the detection of aerobic methanotrophs has resulted in thousands of sequences representing “unknown methanotrophic bacteria.” This limits data interpretation due to restricted information about these uncultured methanotrophs. A few groups of uncultivated methanotrophs are assumed to play important roles in methane oxidation in specific habitats, while the biology behind other sequence clusters remains still largely unknown. The discovery of evolutionary related monooxygenases in non-methanotrophic bacteria and of pmoA paralogs in methanotrophs requires that sequence clusters of uncultivated organisms have to be interpreted with care. This review article describes the present diversity of cultivated and uncultivated aerobic methanotrophic bacteria based on pmoA gene sequence diversity. It summarizes current knowledge about cultivated and major clusters of uncultivated methanotrophic bacteria and evaluates habitat specificity of these bacteria at different levels of taxonomic resolution. Habitat specificity exists for diverse lineages and at different taxonomic levels. Methanotrophic genera such as Methylocystis and Methylocaldum are identified as generalists, but they harbor habitat specific methanotrophs at species level. This finding implies that future studies should consider these diverging preferences at different taxonomic levels when analyzing methanotrophic communities. PMID:26696968

  10. Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria

    NASA Astrophysics Data System (ADS)

    Space Agriculture Task Force; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.

    Manned Mars exploration, especially for extended periods of time, will require recycle of materials to support human life. Here, a conceptual design is developed for a Martian agricultural system driven by biologically regenerative functions. One of the core biotechnologies function is the use of hyper-thermophilic aerobic composting bacterial ecology. These thermophilic bacteria can play an important role in increasing the effectiveness of the processing of human metabolic waste and inedible biomass and of converting them to fertilizer for the cultivation of plants. This microbial technology has been already well established for the purpose of processing sewage and waste materials for small local communities in Japan. One of the characteristics of the technology is that the metabolic heat release that occurs during bacterial fermentation raises the processing temperature sufficiently high at 80 100 °C to support hyper-thermophilic bacteria. Such a hyper-thermophilic system is found to have great capability of decomposing wastes including even their normally recalcitrant components, in a reasonably short period of time and of providing a better quality of fertilizer as an end-product. High quality compost has been shown to be a key element in creating a healthy regenerative food production system. In ground-based studies, the soil microbial ecology after the addition of high quality compost was shown to improve plant growth and promote a healthy symbiosis of arbuscular mycorrhizal fungi. Another advantage of such high processing temperature is the ability to sterilize the pathogenic organisms through the fermentation process and thus to secure the hygienic safety of the system. Plant cultivation is one of the other major systems. It should fully utilize solar energy received on the Martian surface for supplying energy for photosynthesis. Subsurface water and atmospheric carbon dioxide mined on Mars should be also used in the plant cultivation system. Oxygen and food production for human thus rely on local Martian resources. A tree growing subsystem will also give an interesting feature to Martian agriculture. In addition to producing excess oxygen, trees’ rigid body will provide structural material, which can be used for habitat construction. The combination of hyper-thermophilic aerobic composting, plant cultivation, and tree growing with utilizing in-situ natural local resources available on Mars can provide important elements which can enable space agriculture on Mars.

  11. Isolation and preliminary characterization of aerobic heterotrophic bacteria isolated from sub-glacial Antarctic water samples

    NASA Astrophysics Data System (ADS)

    Palma-Alvarez, R.; Lanoil, B. D.

    2002-05-01

    Recently, evidence has been accumulating supporting the presence of biogeochemically active microbial communities in cold, dark, and isolated subglacial environments. These environments are important sites of rock weathering, provide insight into global biogeochemistry during glacial periods, and are potential analogues for ancient Snowball Earth events and the ice-covered oceans of the Jovian moon, Europa. However, the extent of microbial influence on subglacial geochemistry is unclear. As part of an ongoing project to address the extent of that influence, we isolated aerobic heterotrophic bacteria from sediment-laden water from beneath Ice Stream C, a fast moving region of the Western Antarctic Ice Sheet (WAIS). Plates of a standard environmental media (R2A) were prepared at three dilutions (1x, 0.1x, 0.01x) and inoculated in duplicate in a HEPA-filtered environment. One replicate was incubated at 4oC, the other at room temperature in the dark. All plates showed abundant growth, although colony size was positively correlated with media concentration. One-hundred eighty-one colonies total were picked, grown in liquid R2A (1x concentration) at the same initial temperature, and characterized for Gram character, cell shape, cell size, and production of a diffusible yellow pigment with similar chemical characteristics to the siderophore, pyoverdine. Based on these characters, a moderate level of diversity was observed in these isolates. A few types dominated the samples, with several others found only rarely. Further characterization of these isolates is ongoing, and results of these studies and their possible implications for sub-glacial biogeochemistry are discussed.

  12. Phylogenetic diversity and activity of aerobic heterotrophic bacteria from a hypersaline oil-polluted microbial mat.

    PubMed

    Abed, Raeid M M; Zein, Burhanuddin; Al-Thukair, Assad; de Beer, Dirk

    2007-06-01

    The diversity and function of aerobic heterotrophic bacteria (AHB) in cyanobacterial mats have been largely overlooked. We used culture-dependent and molecular techniques to explore the species diversity, degradative capacities and functional guilds of AHB in the photic layer (2mm) of an oil-polluted microbial mat from Saudi Arabia. Enrichment isolation was carried out at different salinities (5% and 12%) and temperatures (28 and 45 degrees C) and on various substrates (acetate, glycolate, Spirulina extract and crude oils). Counts of most probable number showed a numerical abundance of AHB in the range of 1.15-8.13x10(6) cellsg(-1) and suggested the presence of halotolerant and thermotolerant populations. Most of the 16S rRNA sequences of the obtained clones and isolates were phylogenetically affiliated to the groups Gammaproteobacteria, Bacteriodetes and Alphaproteobacteria. Groups like Deltaproteobacteria, Verrucomicrobia, Planctomycetes, Spirochaetes, Acidobacteria and Deinococcus-Thermus were only detected by cloning. The strains isolated on acetate and glycolate belonged to the genera Marinobacter, Halomonas, Roseobacter and Rhodobacter whereas the strains enriched on crude oil belonged to Marinobacter and Alcanivorax. Members of the Bacteriodetes group were only enriched on Spirulina extract indicating their specialization in the degradation of cyanobacterial dead cells. The substrate spectra of representative strains showed the ability of all AHB to metabolize cyanobacterial photosynthetic and fermentation products. However, the unique in situ conditions of the mat apparently favored the enrichment of versatile strains that grew on both the cyanobacterial exudates and the hydrocarbons. We conclude that AHB in cyanobacterial mats represent a diverse community that plays an important role in carbon-cycling within microbial mats. PMID:17056222

  13. Drug resistance and molecular epidemiology of aerobic bacteria isolated from puerperal infections in Bangladesh.

    PubMed

    Ahmed, Salma; Kawaguchiya, Mitsuyo; Ghosh, Souvik; Paul, Shyamal Kumar; Urushibara, Noriko; Mahmud, Chand; Nahar, Kamrun; Hossain, Mohammad Akram; Kobayashi, Nobumichi

    2015-06-01

    Puerperal infection is a common complication during postnatal period in developing countries. Bacterial species, drug resistance, and genetic characteristics were investigated for a total of 470 isolates from puerperal infections in Bangladesh for a 2-year period (2010-2012). The most common species was Escherichia coli (n=98), followed by Enterococcus faecalis (n=54), Staphylococcus haemolyticus (n=33), Proteus mirabilis (n=32), Staphylococcus aureus (n=27), Klebsiella pneumoniae (n=22), and Enterobacter cloacae (n=21). S. aureus and Acinetobacter baumannii were isolated at a higher frequency from wound infections after cesarean section, while E. coli, E. cloacae, and K. pneumoniae were isolated from community-acquired endometritis and urinary tract infections. Resistance to third-generation cephalosporins was frequent for Enterobacteriacae, and was mainly mediated by blaCTX-M-1 group beta-lactamases. The CTX-M gene in E. coli from the four phylogroups was identified as blaCTX-M-15, and phylogroup B2 isolates with blaCTX-M-15 were classified into ST131 with O25b allele, harboring aac(6')-Ib-cr and various virulence factors. Carbapenemase genes blaNDM-1 and blaNDM-7 were identified in one isolate each of phylogroup A E. coli. Methicillin-resistant S. aureus isolates had type IV or V SCCmec, including isolates of ST361 (CC672), which is related to an emerging ST672 clone in the Indian subcontinent. This study revealed the recent epidemiological status of aerobic bacteria causing puerperal infections in Bangladesh, providing useful information to improve clinical practice and infection control. PMID:25555043

  14. Effectiveness of Active Packaging on Control of Escherichia Coli O157:H7 and Total Aerobic Bacteria on Iceberg Lettuce.

    PubMed

    Lu, Haixia; Zhu, Junli; Li, Jianrong; Chen, Jinru

    2015-06-01

    Contaminated leafy green vegetables have been linked to several outbreaks of human gastrointestinal infections. Antimicrobial interventions that are adoptable by the fresh produce industry for control of pathogen contamination are in great demand. This study was undertaken to evaluate the efficacy of sustained active packaging on control of Escherichia coli O157:H7 and total aerobic bacteria on lettuce. Commercial Iceberg lettuce was inoculated with a 3-strain mixture of E. coli O157:H7 at 10(2) or 10(4) CFU/g. The contaminated lettuce and un-inoculated controls were placed respectively in 5 different active packaging structures. Traditional, nonactive packaging structure was included as controls. Packaged lettuce was stored at 4, 10, or 22 °C for 3 wk and sampled weekly for the population of E. coli O157:H7 and total aerobic bacteria. Results showed that packaging structures with ClO2 generator, CO2 generator, or one of the O2 scavengers effectively controlled the growth of E. coli O157:H7 and total aerobic bacteria under all storage conditions. Packaging structure with the ClO2 generator was most effective and no E. coli O157:H7 was detected in samples packaged in this structure except for those that were inoculated with 4 log CFU/g of E. coli O157:H7 and stored at 22 °C. Packaging structures with an oxygen scavenger and the allyl isothiocyanate generator were mostly ineffective in control of the growth of the bacteria on Iceberg lettuce. The research suggests that some of the packaging structures evaluated in the study can be used to control the presence of foodborne pathogens on leafy green vegetables. PMID:25974213

  15. Culturing Aerobic and Anaerobic Bacteria and Mammalian Cells with a Microfluidic Differential Oxygenator

    E-print Network

    Lam, Raymond H. W.

    In this manuscript, we report on the culture of anaerobic and aerobic species within a disposable multilayer polydimethylsiloxane (PDMS) microfluidic device with an integrated differential oxygenator. A gas-filled microchannel ...

  16. Aerobic bacterial flora of oral and nasal fluids of canines with reference to bacteria associated with bites.

    PubMed Central

    Bailie, W E; Stowe, E C; Schmitt, A M

    1978-01-01

    Oral and nasal fluids of 50 dogs were examined to determine the prevalence of aerobic bacteria frequently associated with animal bite wounds. The most frequently isolated microorganisms included: IIj, EF-4, Pasteurella multocida, Staphylococcus aureus, Staphylococcus epidermidis, group D streptococci, Corynebacterium sp., Enterobacteria, Neisseria sp., Moraxella sp., and Bacillus sp. Other species and genera were infrequently recovered and may represent transient flora. The high incidence of IIj, EF-4, P. multocida, and S. aureus, all known human pathogens, suggests that they should be considered as probably contaminants in bite wounds. Images PMID:632349

  17. Respiratory chains from aerobic thermophilic prokaryotes.

    PubMed

    Pereira, Manuela M; Bandeiras, Tiago M; Fernandes, Andreia S; Lemos, Rita S; Melo, Ana M; Teixeira, Miguel

    2004-02-01

    Thermophiles are organisms that grow optimally above 50 degrees C and up to approximately 120 degrees C. These extreme conditions must have led to specific characteristics of the cellular components. In this paper we extensively analyze the types of respiratory complexes from thermophilic aerobic prokaryotes. The different membrane-bound complexes so far characterized are described, and the genomic data available for thermophilic archaea and bacteria are analyzed. It is observed that no specific characteristics can be associated to thermophilicity as the different types of complexes I-IV are present randomly in thermophilic aerobic organisms, as well as in mesophiles. Rather, the extensive genomic analyses indicate that the differences concerning the several complexes are related to the organism phylogeny, i.e., to evolution and lateral gene transfer events. PMID:15168613

  18. Impact of an aerobic thermophilic sequencing batch reactor on antibiotic-resistant anaerobic bacteria in swine waste.

    PubMed

    Chénier, Martin R; Juteau, Pierre

    2009-11-01

    The introduction of antibiotics to animal feed has contributed to the selection of antibiotic-resistant bacteria in concentrated animal feeding operations. The aim of this work was to characterize the impact of an aerobic thermophilic biotreatment on anaerobic antibiotic-resistant bacteria in swine waste. Despite 162- to 6,166-fold reduction in antibiotic-resistant populations enumerated in the swine waste at 25 degrees C and 37 degrees C, resistant populations remained significant (10(4) to 10(5) most probable number per milliliter) in the treated swine waste. Five resistance genes were detected before [tet(LMOS) erm(B)], and six resistance genes were detected after [tet(LMOSY) erm(B)] biotreatment. However, the biotreatment decreased the frequency of detection of resistance genes by 57%. Analysis by denaturing gradient gel electrophoresis of polymerase chain reaction-amplified 16 S ribosomal DNA (rDNA) fragments showed that the biotreatment reduced the bacterial diversity of resistant populations enumerated at 37 degrees C. Cloning and sequencing of the 16 S rDNA of these populations revealed that most clones in the treated swine waste were closely similar to some of the clones retrieved from the untreated swine waste. This study revealed that the aerobic thermophilic biotreatment developed in our laboratory does not prevent the introduction of facultatively anaerobic antibiotic-resistant bacteria and their resistance genes into agricultural ecosystems. Horizontal transfer of ecologically advantageous genes within microbial communities are likely to prevent thermophilic biotreatments from completely eliminating antibiotic-resistant bacteria and their resistance genes in animal wastes. PMID:19562247

  19. Inhibition of Salmonella Typhimurium by Cultures of Cecal Bacteria during Aerobic Incubation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two trials were conducted to examine the ability of cecal bacterial cultures from broilers to inhibit growth of Salmonella Typhimurium during aerobic incubation. Cecal broth media was inoculated with 10 µl of cecal contents from 6 week old broilers taken from 2 separate flocks. Cultures were incubat...

  20. Phylogenetic analysis of nitric oxide reductase gene homologues from aerobic ammonia-oxidizing bacteria

    E-print Network

    Ward, Bess

    Phylogenetic analysis of nitric oxide reductase gene homologues from aerobic ammonia). The ammonia-oxidizing bacterium Nitrosomonas europaea also possesses a functional nitric oxide reductase subunit of nitric oxide reductase (norB) were obtained from eight additional strains of ammonia

  1. Remediation of polychlorinated biphenyl impacted sediment by concurrent bioaugmentation with anaerobic halorespiring and aerobic degrading bacteria

    PubMed Central

    Payne, Rayford B.; Fagervold, Sonja K.; May, Harold D.; Sowers, Kevin R.

    2013-01-01

    Bioremediation of sediments contaminated with commercial PCBs is potentially achievable by the sequential activity of anaerobic halorespiration to convert higher chlorinated congeners to less chlorinated congeners that are susceptible to aerobic respiratory degradation. The efficacy of bioaugmentation with anaerobic halorespiring “Dehalobium chlorocoercia” DF1 and aerobic Burkholderia xenovorans LB400 added concurrently with GAC as a delivery system was determined in 2-liter laboratory mesocosms containing weathered Aroclor-contaminated sediment from Baltimore Harbor, MD. The greatest effect was seen in the mesocosm bioaugmented with both DF1 and LB400 together, which resulted in an 80% decrease by mass of PCBs, from 8 mg/kg to less than 2 mg/kg after 120 days. There was no significant increase in lesser-chlorinated congeners, indicating that both anaerobic dechlorination by DF1 and aerobic degradation by LB400 occurred. In contrast, non-bioaugmented controls containing filtered culture supernatant showed only 25% decrease in total levels of PCBs after 365 days, which was likely due to biostimulation of the indigenous population by the medium. Direct colony counts and molecular analysis targeting a putative reductive dehalogenase gene of D. chlorocoercia, or the bphA gene of LB400 showed the presence of viable DF1 and LB400 in bioaugmented mesocosms after 365 days, indicating that both non-indigenous strains were sustainable within the indigenous microbial community. These results suggest that an in situ treatment employing the simultaneous application of anaerobic and aerobic microorganisms could be an effective, environmentally sustainable strategy to reduce PCBs levels in contaminated sediment. PMID:23463900

  2. A new environment for aerobic anoxygenic phototrophic bacteria: biological soil crusts.

    PubMed

    Csotonyi, Julius T; Swiderski, Jolantha; Stackebrandt, Erko; Yurkov, Vladimir

    2010-10-01

    Phototrophic microorganisms are critical to the carbon cycling and productivity of biological soil crusts, which enhance water content, nutrient relations and mechanical stability of arid soils. Only oxygen-producing phototrophs, including cyanobacteria and algae, are known from soil crusts, but Earth's second major branch of photosynthetic organisms, the evolutionarily earlier anoxygenic phototrophs, is unreported. We announce the discovery of aerobic anoxygenic phototrophs in three Canadian soil crust communities. We found in a culture-based study that they comprised 0.1-5.9% of the cultivable bacterial community in moss-, lichen- and cyanobacteria-dominated crust from sand dunes and sandy soils. Comparable in density to aerobic phototrophs in other habitats, the bacteriochlorophyll a-possessing pink and orange isolates were related to species of Methylobacterium (99.0-99.5%), Belnapia (97.4-98.8%), Muricoccus (94.4%) and Sphingomonas (96.6-98.5%), based on 16S rRNA gene sequences. Our results demonstrate that proteobacterial anoxygenic phototrophs may be found in dry soil environments, implying desiccation resistance as yet unreported for this group. By utilizing sunlight for part of their energy needs, aerobic phototrophs can accelerate organic carbon cycling in nutrient-poor arid soils. Their effects will be especially important as global climate change enhances soil erosion and consequent nutrient loss. PMID:23766251

  3. Radioassay for Hydrogenase Activity in Viable Cells and Documentation of Aerobic Hydrogen-Consuming Bacteria Living in Extreme Environments

    PubMed Central

    Schink, Bernhard; Lupton, F. S.; Zeikus, J. G.

    1983-01-01

    An isotopic tracer assay based on the hydrogenase-dependent formation of tritiated water from tritium gas was developed for in life analysis of microbial hydrogen transformation. This method allowed detection of bacterial hydrogen metabolism in pure cultures or in natural samples obtained from aquatic ecosystems. A differentiation between chemical-biological and aerobic-anaerobic hydrogen metabolism was established by variation of the experimental incubation temperature or by addition of selective inhibitors. Hydrogenase activity was shown to be proportional to the consumption or production of hydrogen by cultures of Desulfovibrio vulgaris, Clostridium pasteurianum, and Methanosarcina barkeri. This method was applied, in connection with measurements of free hydrogen and most-probable-number enumerations, in aerobic natural source waters to establish the activity and document the ecology of hydrogen-consuming bacteria in extreme acid, thermal, or saline environments. The utility of the assay is based in part on the ability to quantify bacterial hydrogen transformation at natural hydrogen partial pressures, without the use of artificial electron acceptors. PMID:16346288

  4. Comparative in vitro activity of the new oral cephalosporin Bay v 3522 against aerobic and anaerobic bacteria.

    PubMed

    Rylander, M; Nord, C E; Norrby, S R

    1990-10-01

    The in vitro activity of the new oral cephalosporin Bay v 3522 against 229 aerobic and 330 anaerobic clinical isolates was determined using the agar dilution technique. For comparison, amoxicillin, amoxicillin/clavulanate, cefaclor, cefadroxil, cefuroxime, cephalexin, ciprofloxacin, clindamycin, co-trimoxazole, doxycycline, erythromycin and metronidazole (only anaerobic bacteria) were tested. Bay v 3522 was found to have high activity against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pneumoniae, Streptococcus pyogenes, Branhamella catarrhalis, Haemophilus influenzae, anaerobic cocci, Propionibacterium acnes, Clostridium perfringens and fusobacteria. When tested against a higher inoculum or using the broth dilution technique, the activity of Bay v 3522 showed little dependence on inoculum size and the bactericidal activity was similar to inhibitory activity in most bacterial groups. Bay v 3522 may be useful in the treatment of skin, soft tissue and respiratory tract infections. Clinical studies are thus warranted. PMID:2261923

  5. Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria

    NASA Astrophysics Data System (ADS)

    Kanazawa, S.; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.; Space Agriculture Task Force, J.

    Manned Mars exploration requires recycle of materials to support human life A conceptual design is developed for space agriculture which is driven by the biologically regenerative function Hyper-thermophilic aerobic composting bacterial ecology is the core of materials recycling system to process human metabolic waste and inedible biomass and convert them to fertilizer for plants cultivation A photosynthetic reaction of plants will be driven by solar energy Water will be recycled by cultivation of plants and passing it through plant bodies Sub-surface water and atmospheric carbon dioxide are the natural resource available on Mars and these resources will be converted to oxygen and foods We envision that the agricultural system will be scaled up by importing materials from Martian environment Excess oxygen will be obtained from growing trees for structural and other components Minor elements including N P K and other traces will be introduced as fertilizers or nutrients into the agricultural materials circulation Nitrogen will be collected from Martian atmosphere We will assess biological fixation of nitrogen using micro-organisms responsible in Earth biosphere Hyper-thermophilic aerobic bacterial ecology is effective to convert waste materials into useful forms to plants This microbial technology has been well established on ground for processing sewage and waste materials For instance the hyper-thermophilic bacterial system is applied to a composting machine in a size of a trash box in home kitchen Since such a home electronics

  6. Colonization by aerobic bacteria in karst: laboratory and in situ experiments.

    PubMed

    Personné, J C; Poty, F; Mahler, B J; Drogue, C

    2004-01-01

    Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton. PMID:15318775

  7. Colonization by aerobic bacteria in karst: Laboratory and in situ experiments

    USGS Publications Warehouse

    Personne, J.-C.; Poty, F.; Mahler, B.J.; Drogue, C.

    2004-01-01

    Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton.

  8. Plant pathogenic anaerobic bacteria use aromatic polyketides to access aerobic territory.

    PubMed

    Shabuer, Gulimila; Ishida, Keishi; Pidot, Sacha J; Roth, Martin; Dahse, Hans-Martin; Hertweck, Christian

    2015-11-01

    Around 25% of vegetable food is lost worldwide because of infectious plant diseases, including microbe-induced decay of harvested crops. In wet seasons and under humid storage conditions, potato tubers are readily infected and decomposed by anaerobic bacteria (Clostridium puniceum). We found that these anaerobic plant pathogens harbor a gene locus (type II polyketide synthase) to produce unusual polyketide metabolites (clostrubins) with dual functions. The clostrubins, which act as antibiotics against other microbial plant pathogens, enable the anaerobic bacteria to survive an oxygen-rich plant environment. PMID:26542569

  9. Effect of applying lactic acid bacteria and propionic acid on fermentation quality and aerobic stability of oats-common vetch mixed silage on the Tibetan plateau.

    PubMed

    Zhang, Jie; Guo, Gang; Chen, Lei; Li, Junfeng; Yuan, Xianjun; Yu, Chengqun; Shimojo, Masataka; Shao, Tao

    2015-06-01

    The objective of this study was to evaluate effects of lactic acid bacteria and propionic acid on the fermentation quality and aerobic stability of oats-common vetch mixed silage by using a small-scale fermentation system on the Tibetan plateau. (i) An inoculant (Lactobacillus plantarum) (L) or (ii) propionic acid (P) or (iii) inoculant?+ propionic acid (PL) were used as additives. After fermenting for 60 days, silos were opened and the aerobic stability was tested for the following 15 days. The results showed that all silages were well preserved with low pH and NH3 -N, and high lactic acid content and V-scores. L and PL silages showed higher (P < 0.05) lactic acid and crude protein content than the control silage. P silage inhibited lactic acid production. Under aerobic conditions, L silage had similar yeast counts as the control silage (> 10(5) cfu/g fresh matter (FM)); however, it numerically reduced aerobic stability for 6 h. P and PL silages showed fewer yeasts (< 10(5) cfu/g FM) (P < 0.05) and markedly improved the aerobic stability (> 360 h). The result suggested that PL is the best additive as it could not only improved fermentation quality, but also aerobic stability of oats-common vetch mixed silage on the Tibetan plateau. PMID:25494579

  10. Anaerobic and aerobic bacteriology of the saliva and gingiva from 16 captive Komodo dragons (Varanus komodoensis): new implications for the "bacteria as venom" model.

    PubMed

    Goldstein, Ellie J C; Tyrrell, Kerin L; Citron, Diane M; Cox, Cathleen R; Recchio, Ian M; Okimoto, Ben; Bryja, Judith; Fry, Bryan G

    2013-06-01

    It has been speculated that the oral flora of the Komodo dragon (Varanus komodoensis) exerts a lethal effect on its prey; yet, scant information about their specific oral flora bacteriology, especially anaerobes, exists. Consequently, the aerobic and anaerobic oral bacteriology of 16 captive Komodo dragons (10 adults and six neonates), aged 2-17 yr for adults and 7-10 days for neonates, from three U.S. zoos were studied. Saliva and gingival samples were collected by zoo personnel, inoculated into anaerobic transport media, and delivered by courier to a reference laboratory. Samples were cultured for aerobes and anaerobes. Strains were identified by standard methods and 16S rRNA gene sequencing when required. The oral flora consisted of 39 aerobic and 21 anaerobic species, with some variation by zoo. Adult dragons grew 128 isolates, including 37 aerobic gram-negative rods (one to eight per specimen), especially Enterobacteriaceae; 50 aerobic gram-positive bacteria (two to nine per specimen), especially Staphylococcus sciuri and Enterococcusfaecalis, present in eight of 10 and nine of 10 dragons, respectively; and 41 anaerobes (one to six per specimen), especially clostridia. All hatchlings grew aerobes but none grew anaerobes. No virulent species were isolated. As with other carnivores, captive Komodo oral flora is simply reflective of the gut and skin flora of their recent meals and environment and is unlikely to cause rapid fatal infection. PMID:23805543

  11. Patterns in Abundance, Cell Size and Pigment Content of Aerobic Anoxygenic Phototrophic Bacteria along Environmental Gradients in Northern Lakes

    PubMed Central

    Fauteux, Lisa; Cottrell, Matthew T.; Kirchman, David L.; Borrego, Carles M.; Garcia-Chaves, Maria Carolina; del Giorgio, Paul A.

    2015-01-01

    There is now evidence that aerobic anoxygenic phototrophic (AAP) bacteria are widespread across aquatic systems, yet the factors that determine their abundance and activity are still not well understood, particularly in freshwaters. Here we describe the patterns in AAP abundance, cell size and pigment content across wide environmental gradients in 43 temperate and boreal lakes of Québec. AAP bacterial abundance varied from 1.51 to 5.49 x 105 cells mL-1, representing <1 to 37% of total bacterial abundance. AAP bacteria were present year-round, including the ice-cover period, but their abundance relative to total bacterial abundance was significantly lower in winter than in summer (2.6% and 7.7%, respectively). AAP bacterial cells were on average two-fold larger than the average bacterial cell size, thus AAP cells made a greater relative contribution to biomass than to abundance. Bacteriochlorophyll a (BChla) concentration varied widely across lakes, and was not related to AAP bacterial abundance, suggesting a large intrinsic variability in the cellular pigment content. Absolute and relative AAP bacterial abundance increased with dissolved organic carbon (DOC), whereas cell-specific BChla content was negatively related to chlorophyll a (Chla). As a result, both the contribution of AAP bacteria to total prokaryotic abundance, and the cell-specific BChla pigment content were positively correlated with the DOC:Chla ratio, both peaking in highly colored, low-chlorophyll lakes. Our results suggest that photoheterotrophy might represent a significant ecological advantage in highly colored, low-chlorophyll lakes, where DOC pool is chemically and structurally more complex. PMID:25927833

  12. Aerobic degradation of a mixture of azo dyes in a packed bed reactor having bacteria-coated laterite pebbles.

    PubMed

    Senan, Resmi C; Shaffiqu, T S; Roy, J Jegan; Abraham, T Emilia

    2003-01-01

    A microbial consortium capable of aerobic degradation of a mixture of azo dyes consisting of two isolated strains (RRL,TVM) and one known strain of Pseudomonas putida (MTCC 1194) was immobilized on laterite stones. The amount of bacterial biomass attached to the laterite stones was 8.64 g per 100 g of the stone on a dry weight basis. The packed bed reactor was filled with these stones and had a total capacity of 850 mL and a void volume of 210 mL. The feed consisted of an equal mixture of seven azo dyes both in water as well as in a simulated textile effluent, at a pH of 9.0 and a salinity of 900 mg/L. The dye concentrations of influent were 25, 50, and 100 microg/mL. The residence time was varied between 0.78 and 6.23 h. It was found that at the lowest residence time 23.55, 45.73, and 79.95 microg of dye was degraded per hour at an initial dye concentration of 25, 50, and 100 microg, respectively. The pH was reduced from 9.0 to 7.0. Simulated textile effluent containing 50 microg/mL dye was degraded by 61.7%. Analysis of degradation products by TLC and HPLC showed that the dye mixture was degraded to nontoxic smaller molecules. The bacteria-coated pebbles were stable, there was no washout even after 2 months, and the reactor was found to be suitable for the aerobic degradation of azo dyes. PMID:12675610

  13. Mechanisms regulating the reduction of selenite by aerobic gram (+) and ({minus}) bacteria

    SciTech Connect

    Garbisu, C.; Ishii, Takahisa; Yee, B.C.; Carlson, D.E.; Buchanan, B.B.; Leighton, T.; Smith, N.R.; Yee, A.

    1995-12-31

    Toxic species of selenium are pollutants found in agricultural and oil refinery wastestreams. Selenium contamination is particularly problematic in areas that have seleniferous subsurface geology, such as the central valley of California. The authors are developed a bacterial treatment system to mitigate selenium-contaminated wastestreams using Bacillus subtilis and Pseudomonas fluorescens, respectively, as model gram (+) and ({minus}) soil bacteria. They have found that, during growth, both organisms reduce selenite, a major soluble toxic species, to red elemental selenium--an insoluble product generally regarded as nontoxic. In both cases, reduction depended on growth substrate and was effected by an inducible system that effectively removed selenite at concentrations typical of polluted sites--i.e., 50 to 300 {micro}g/L. The bacteria studied differed in one respect: when grown in medium supplemented with nitrate or sulfate, the ability of P. fluorescens to remediate selenite was enhanced, whereas that of B. subtilis was unchanged. Current efforts are being directed toward understanding the biochemical mechanism(s) of detoxification and determining whether bacteria occurring in polluted environments such as soils and sludge systems are capable of selenite remediation.

  14. Complete Genome Sequence of the Aerobic Marine Methanotroph Methylomonas methanica MC09

    SciTech Connect

    Boden, Rich; Cunliffe, Michael; Scanlan, Julie; Moussard, Helene; Kits, K. Dimitri; Klotz, Martin G; Jetten, MSM; Vuilleumier, Stephane; Han, James; Peters, Lin; Mikhailova, Natalia; Teshima, Hazuki; Tapia, Roxanne; Kyrpides, Nikos C; Ivanova, N; Pagani, Ioanna; Cheng, Jan-Fang; Goodwin, Lynne A.; Han, Cliff; Hauser, Loren John; Land, Miriam L; Lapidus, Alla L.; Lucas, Susan; Pitluck, Sam; Woyke, Tanja; Stein, Lisa Y.; Murrell, Collin

    2011-01-01

    Methylomonas methanica MC09 is a mesophilic, halotolerant, aerobic, methanotrophic member of the Gammaproteobacteria, isolated from coastal seawater. Here we present the complete genome sequence of this strain, the first available from an aerobic marine methanotroph.

  15. Formation of Polyhydroxyalkanoate in Aerobic Anoxygenic Phototrophic Bacteria and Its Relationship to Carbon Source and Light Availability?

    PubMed Central

    Xiao, Na; Jiao, Nianzhi

    2011-01-01

    Aerobic anoxygenic phototrophic bacteria (AAPB) are unique players in carbon cycling in the ocean. Cellular carbon storage is an important mechanism regulating the nutrition status of AAPB but is not yet well understood. In this paper, six AAPB species (Dinoroseobacter sp. JL1447, Roseobacter denitrificans OCh 114, Roseobacter litoralis OCh 149, Dinoroseobacter shibae DFL 12T, Labrenzia alexandrii DFL 11T, and Erythrobacter longus DSMZ 6997) were examined, and all of them demonstrated the ability to form the carbon polymer polyhydroxyalkanoate (PHA) in the cell. The PHA in Dinoroseobacter sp. JL1447 was identified as poly-beta-hydroxybutyrate (PHB) according to evidence from Fourier transform infrared spectroscopy, differential scanning calorimetry, and 1H nuclear magnetic resonance spectroscopy examinations. Carbon sources turned out to be critical for PHA production in AAPB. Among the eight media tested with Dinoroseobacter sp. JL1447, sodium acetate, giving a PHA production rate of 72%, was the most productive carbon source, followed by glucose, with a 68% PHA production rate. Such PHA production rates are among the highest recorded for all bacteria. The C/N ratio of substrates was verified by the experiments as another key factor in PHA production. In the case of R. denitrificans OCh 114, PHA was not detected when the organism was cultured at C/N ratios of <2 but became apparent at C/N ratios of >3. Light is also important for the formation of PHA in AAPB. In the case of Dinoroseobacter sp. JL1447, up to a one-quarter increase in PHB production was observed when the culture underwent growth in a light-dark cycle compared to growth completely in the dark. PMID:21908634

  16. Aminopeptidase activity by spoilage bacteria and its relationship to microbial load and sensory attributes of poultry legs during aerobic cold storage.

    PubMed

    Guevara-Franco, José Alfredo; Alonso-Calleja, Carlos; Capita, Rosa

    2010-02-01

    The shelf life of poultry legs stored aerobically and the possible role of the aminopeptidase activity of gram-negative bacteria (p-nitroaniline test) as a predictor of poultry spoilage were evaluated on the basis of microbiological and sensory parameters. Chicken legs (n = 30) obtained immediately after evisceration in a local poultry processing plant were kept under aerobic refrigeration (4 +/- 1 degrees C) for 7 days. Microbiological (counts of aerobic bacteria and psychrotrophs) and sensory (odor, color, and general acceptability on a hedonic scale of 1 to 9) parameters and aminopeptidase activity (absorbance at 390 nm [A(390)]) determinations were performed after 0, 1, 3, 5, and 7 days of storage. Aerobic plate counts of 7 log CFU/g and a score of 6 for general acceptability were used as indicators of the end point of shelf life. Strong correlations (r > or = 0.76; P < 0.001) were obtained between bacterial counts, hedonic scores, and A(390) values. Samples were judged as unacceptable (shelf-life end point) after 2 and 4 days on the basis of sensory and microbiological analyses, respectively. A(390) values of 0.52 and 0.89 (corresponding to p-nitroaniline concentrations of 6.25 and 10.7 microg/ml, respectively) are proposed as the upper limits for acceptability on the basis of sensory and microbiological determinations, respectively. However, these recommendations are based on a small set of samples, and their general application is yet to be verified. PMID:20132678

  17. Isolation of aerobic cultivable cellulolytic bacteria from different regions of the gastrointestinal tract of giant land snail Achatina fulica.

    PubMed

    Pinheiro, Guilherme L; Correa, Raquel F; Cunha, Raquel S; Cardoso, Alexander M; Chaia, Catia; Clementino, Maysa M; Garcia, Eloi S; de Souza, Wanderley; Frasés, Susana

    2015-01-01

    The enzymatic hydrolysis of cellulose by cellulases is one of the major limiting steps in the conversion of lignocellulosic biomass to yield bioethanol. To overcome this hindrance, significant efforts are underway to identify novel cellulases. The snail Achatina fulica is a gastropod with high cellulolytic activity, mainly due to the abundance of glycoside hydrolases produced by both the animal and its resident microbiota. In this study, we partially assessed the cellulolytic aerobic bacterial diversity inside the gastrointestinal tract of A. fulica by culture-dependent methods and evaluated the hydrolytic repertoire of the isolates. Forty bacterial isolates were recovered from distinct segments of the snail gut and identified to the genus level by 16S rRNA gene sequence analysis. Additional phenotypic characterization was performed using biochemical tests provided by the Vitek2 identification system. The overall enzymatic repertoire of the isolated strains was investigated by enzymatic plate assays, containing the following substrates: powdered sugarcane bagasse, carboxymethylcellulose (CMC), p-nitrophenyl-?-D-glucopyranoside (pNPG), p-nitrophenyl-?-D-cellobioside (pNPC), 4-methylumbelliferyl-?-D-glucopyranoside (MUG), 4-methylumbelliferyl-?-D-cellobioside (MUC), and 4-methylumbelliferyl-?-D-xylopyranoside (MUX). Our results indicate that the snail A. fulica is an attractive source of cultivable bacteria that showed to be valuable resources for the production of different types of biomass-degrading enzymes. PMID:26347735

  18. Isolation of aerobic cultivable cellulolytic bacteria from different regions of the gastrointestinal tract of giant land snail Achatina fulica

    PubMed Central

    Pinheiro, Guilherme L.; Correa, Raquel F.; Cunha, Raquel S.; Cardoso, Alexander M.; Chaia, Catia; Clementino, Maysa M.; Garcia, Eloi S.; de Souza, Wanderley; Frasés, Susana

    2015-01-01

    The enzymatic hydrolysis of cellulose by cellulases is one of the major limiting steps in the conversion of lignocellulosic biomass to yield bioethanol. To overcome this hindrance, significant efforts are underway to identify novel cellulases. The snail Achatina fulica is a gastropod with high cellulolytic activity, mainly due to the abundance of glycoside hydrolases produced by both the animal and its resident microbiota. In this study, we partially assessed the cellulolytic aerobic bacterial diversity inside the gastrointestinal tract of A. fulica by culture-dependent methods and evaluated the hydrolytic repertoire of the isolates. Forty bacterial isolates were recovered from distinct segments of the snail gut and identified to the genus level by 16S rRNA gene sequence analysis. Additional phenotypic characterization was performed using biochemical tests provided by the Vitek2 identification system. The overall enzymatic repertoire of the isolated strains was investigated by enzymatic plate assays, containing the following substrates: powdered sugarcane bagasse, carboxymethylcellulose (CMC), p-nitrophenyl-?-D-glucopyranoside (pNPG), p-nitrophenyl-?-D-cellobioside (pNPC), 4-methylumbelliferyl-?-D-glucopyranoside (MUG), 4-methylumbelliferyl-?-D-cellobioside (MUC), and 4-methylumbelliferyl-?-D-xylopyranoside (MUX). Our results indicate that the snail A. fulica is an attractive source of cultivable bacteria that showed to be valuable resources for the production of different types of biomass-degrading enzymes. PMID:26347735

  19. Production of autoinducer-2 by aerobic endospore-forming bacteria isolated from the West African fermented foods.

    PubMed

    Qian, Yang; Kando, Christine Kere; Thorsen, Line; Larsen, Nadja; Jespersen, Lene

    2015-11-01

    Autoinducer-2 (AI-2) is a quorum-sensing (QS) molecule which mediates interspecies signaling and affects various bacterial behaviors in food fermentation. Biosynthesis of AI-2 is controlled by S-ribosylhomocysteine lyase encoded by the luxS gene. The objective of this study was to investigate production of AI-2 by aerobic endospore-forming bacteria (AEB) isolated from the West African alkaline fermented seed products Mantchoua and Maari. The study included 13 AEB strains of Bacillus subtilis, B. cereus, B. altitudinis, B. amyloliquefaciens, B. licheniformis, B. aryabhattai, B. safensis, Lysinibacillus macroides and Paenibacillus polymyxa. All the tested strains harbored the luxS gene and all strains except for P. polymyxa B314 were able to produce AI-2 during incubation in laboratory medium. Production of AI-2 by AEB was growth phase dependent, showing maximum activity at the late exponential phase. AI-2 was depleted from the culture medium at the beginning of the stationary growth phase, indicating that the tested AEB possess a functional AI-2 receptor that internalizes AI-2. This study provides the evidences of QS system in Bacillus spp. and L. macroides and new knowledge of AI-2 production by AEB. This knowledge contributes to the development of QS-based strategies for better control of alkaline fermentation. PMID:26449556

  20. A Reference Broth Microdilution Method for Dalbavancin In Vitro Susceptibility Testing of Bacteria that Grow Aerobically.

    PubMed

    Koeth, Laura M; DiFranco-Fisher, Jeanna M; McCurdy, Sandra

    2015-01-01

    Antimicrobial susceptibility testing (AST) is performed to assess the in vitro activity of antimicrobial agents against various bacteria. The AST results, which are expressed as minimum inhibitory concentrations (MICs) are used in research for antimicrobial development and monitoring of resistance development and in the clinical setting for antimicrobial therapy guidance. Dalbavancin is a semi-synthetic lipoglycopeptide antimicrobial agent that was approved in May 2014 by the Food and Drug Administration (FDA) for the treatment of acute bacterial skin and skin structure infections caused by Gram-positive organisms. The advantage of dalbavancin over current anti-staphylococcal therapies is its long half-life, which allows for once-weekly dosing. Dalbavancin has activity against Staphylococcus aureus (including both methicillin-susceptible S. aureus [MSSA] and methicillin-resistant S. aureus [MRSA]), coagulase-negative staphylococci, Streptococcus pneumoniae, Streptococcus anginosus group, ?-hemolytic streptococci and vancomycin susceptible enterococci. Similar to other recent lipoglycopeptide agents, optimization of CLSI and ISO broth susceptibility test methods includes the use of dimethyl sulfoxide (DMSO) as a solvent when preparing stock solutions and polysorbate 80 (P80) to alleviate adherence of the agent to plastic. Prior to the clinical studies and during the initial development of dalbavancin, susceptibility studies were not performed with the use of P-80 and MIC results tended to be 2-4 fold higher and similarly higher MIC results were obtained with the agar dilution susceptibility method. Dalbavancin was first included in CLSI broth microdilution methodology tables in 2005 and amended in 2006 to clarify use of DMSO and P-80. The broth microdilution (BMD) procedure shown here is specific to dalbavancin and is in accordance with the CLSI and ISO methods, with step-by-step detail and focus on the critical steps added for clarity. PMID:26381422

  1. The determination of the real nano-scale sizes of bacteria in chernozem during microbial succession by means of hatching of a soil in aerobic and anaerobic conditions

    NASA Astrophysics Data System (ADS)

    Gorbacheva, M.

    2012-04-01

    M.A. Gorbacheva,L.M. Polyanskaya The Faculty of Soil Science, Moscow State University, Leninskie Gory, GSP-1, Moscow,119991,Russia In recent years there's been particular attention paid to the smallest life's forms- bacteria which size can be measured in nanometer. These are the forms of bacteria with diameter of 5-200 nm. Theoretical calculations based on the content of the minimum number of DNA, enzyme, lipids in and ribosome in cells indicates impossibility of existence of a living cells within diameter less than 300 nm. It is theoretically possible for a living cell to exist within possible diameter of approximately 140 nm. Using a fluorescence microscope there's been indicated in a number of samples from lakes, rivers, soil, snow and rain water that 200 nm is the smallest diameter of a living cell. Supposingly, such a small size of bacteria in soil is determined by natural conditions which limit their development by nutritious substances and stress-factors. Rejuvenescence of nanobacteria under unfavourable natural conditions and stress-factors is studied in laboratory environment. The object of the current study has become the samples of typical arable chernozem of the Central Chernozem State Biosphere Reserve in Kursk. The detailed morphological description of the soil profile and its basic analytical characteristics are widely represented in scientific publications. The soil is characterized by a high carbon content which makes up 3,96% ,3,8% , and 2,9% for the upper layers of the A horizon, and 0,79% for the layer of the B horizon. A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in upper A horizons and B horizon of a chernozem. The final aim is to identify the cells size of bacteria in aerobic and anaerobic soil conditions in chernozem during the microbial succession, by dampening and application of chitin by means of «cascade filtration» method. The study of the microcosms is important for understanding natural mechanisms in soil and will be useful for the development of new soil models in laboratory. Thus, by means of «cascade filtration» method there've been made some results on true size, quantity and biomass of bacteria. Development of a bacteria in various soil horizons and their layers in aerobic and anaerobic conditions and calculations of biomass of bacteria in upper layer horizon A and lower layer horizon B have also become the subjects of the studies. It was identified that the quantity of bacteria in aerobic conditions increase during the microbial succession while bacteria sized 230 and 380 nm were dominating. In anaerobic conditions the process of connecting cells sized 170 nm and bacteria is observed. Biomass of bacteria is higher in anaerobic conditions in upper layer horizon A because of elevated variety of bacteria. In horizon B in anaerobic conditions it is of maximum because of anaerobic situation in situ. Thus, distribution of bacteria's size depends on aeration of soil. That helps to acknowledge the receipt of theory of a great number of researchers about that fact that the size of bacteria in the soil in anaerobic conditions decrease under stress-factors. This work touches upon such a poorly investigated subject as nanobacteria in the soil. But this knowledge plays a significant role in land reclamation oil-cut and prognostication pollution of the soil by pathogenic bacteria.

  2. Evaluation of Petrifilm methods for enumeration of aerobic flora and coliforms in a wide range of foods.

    PubMed

    Blackburn, C W; Baylis, C L; Petitt, S B

    1996-02-01

    Petrifilm is a ready-to-use alternative to traditional microbial enumeration methods. The Petrifilm Aerobic Count Plate (ACP) and Coliform Count Plate (CCP) were compared with standard methods for the enumeration of the aerobic mesophilic flora and coliform bacteria in 91 foods covering a wide range of different food commodities. There was good correlation between the Petrifilm ACP and the standard aerobic colony count method (r = 0.989) and between the Petrifilm CCP and the standard Violet Red Bile Agar plating method (r = 0.872). In both cases, the Petrifilm methods had a better repeatability than the standard methods. The Petrifilm ACP and CCP were shown to be practical and accurate alternatives to standard enumeration methods in a wide range of foods, with benefits of saving time, labour and incubator space. PMID:8936373

  3. [Anoxygenic phototrophic bacteria from microbial communities of Goryachinsk Thermal Spring (Baikal Area, Russia)].

    PubMed

    Kalashnikov, A M; Ga?sin, V A; Sukhacheva, M V; Namsaraeva, B B; Panteleeva, A N; Nuianzina-Boldareva, E N; Kuznetsov, B B; Gorlenko, V M

    2014-01-01

    Species composition of anoxygenic phototrophic bacteria in microbial mats of the Goryachinsk thermal spring was investigated along the temperature gradient. The spring belonging to nitrogenous alkaline hydrotherms is located at the shore of Lake Baikal 188 km north-east from Ulan-Ude. The water is of the sulfate-sodium type, contains trace amounts of sulfide, salinity does not exceed 0.64 g/L, pH 9.5. The temperature at the outlet of the spring may reach 54 degrees C. The cultures of filamentous anoxygenic phototrophic bacteria, nonsulfur and sulfur purple bacteria, and aerobic anoxygenic phototrophic bacteria were identified using the pufLM molecular marker. The fmoA marker was used for identification of green sulfur bacteria. Filamentous cyanobacteria predominated in the mats, with anoxygenic phototrophs comprising a minor component of the phototrophic communities. Thermophilic bacteria Chloroflexus aurantiacus were detected irn the samples from both the thermophilic and mesophilic mats. Cultures ofnonsulfur purple bacteria similar to Blastochloris sulfoviridis and Rhodomicrobium vannielii were isolatd from the mats developing at high (50.6-49.4 degrees C) and low temperatures (45-20 degrees C). Purple sulfur bacteria Allochromatium sp. and Thiocapsa sp., as well as green sulfur bacteria Chlorobium sp., were revealedin low-temperature mats. Truly thermophilic purple and gree sulfur bacteria were not found in the spring. Anoxygenic phototrophic bacteria found in the spring were typical of the sulfuret communities, for which the sulfur cycle is mandatory. The presence of aerobic bacteriochlorophylla-containing bacteria identified as Agrobacterium (Rhizobium) tumifaciens in the mesophilic (20 degrees C) mat is of interest. PMID:25844460

  4. Nitrogen removal characteristics of enhanced in situ indigenous aerobic denitrification bacteria for micro-polluted reservoir source water.

    PubMed

    Zhou, Shilei; Huang, Tinglin; Zhang, Haihan; Zeng, Mingzheng; Liu, Fei; Bai, Shiyuan; Shi, Jianchao; Qiu, Xiaopeng; Yang, Xiao

    2016-02-01

    Indigenous oligotrophic aerobic denitrifiers nitrogen removal characteristics, community metabolic activity and functional genes were analyzed in a micro-polluted reservoir. The results showed that the nitrate in the enhanced system decreased from 1.71±0.01 to 0.80±0.06mg/L, while the control system did little to remove and there was no nitrite accumulation. The total nitrogen (TN) removal rate of the enhanced system reached 38.33±1.50% and the TN removal rate of surface sediment in the enhanced system reached 23.85±2.52%. TN removal in the control system experienced an 85.48±2.37% increase. The densities of aerobic denitrifiers in the enhanced system ranged from 2.24×10(5) to 8.13×10(7)cfu/mL. The abundance of nirS and nirK genes in the enhanced system were higher than those of in the control system. These results suggest that the enhanced in situ indigenous aerobic denitrifiers have potential applications for the bioremediation of micro-polluted reservoir system. PMID:26649898

  5. Specialized cell surface structures in cellulolytic bacteria.

    PubMed Central

    Lamed, R; Naimark, J; Morgenstern, E; Bayer, E A

    1987-01-01

    The cell surface topology of various gram-negative and -positive, anaerobic and aerobic, mesophilic and thermophilic, cellulolytic and noncellulolytic bacteria was investigated by scanning electron microscopic visualization using cationized ferritin. Characteristic protuberant structures were observed on cells of all cellulolytic strains. These structures appeared to be directly related to the previously described exocellular cellulase-containing polycellulosomes of Clostridium thermocellum YS (E. A. Bayer and R. Lamed, J. Bacteriol. 167:828-836, 1986). Immunochemical evidence and lectin-binding studies suggested a further correlation on the molecular level among cellulolytic bacteria. The results indicate that such cell surface cellulase-containing structures may be of general consequence to the bacterial interaction with and degradation of cellulose. Images PMID:3301817

  6. The hydrological context determines the beta-diversity of aerobic anoxygenic phototrophic bacteria in European Arctic seas but does not favor endemism

    PubMed Central

    Lehours, Anne-Catherine; Jeanthon, Christian

    2015-01-01

    Despite an increasing number of studies over the last 15 years, aerobic anoxygenic photoheterotrophic (AAP) bacteria remain a puzzling functional group in terms of physiology, metabolism, and ecology. To contribute to a better knowledge of their environmental distribution, the present study aims at analyzing their diversity and structure at the boundary between the Norwegian, Greenland, and Barents Seas. The polymorphism of a marker gene encoding a sub-unit of the photosynthetic apparatus (pufM gene) was analyzed and attempted to be related to environmental parameters. The Atlantic or Arctic origin of water masses had a strong impact on the AAP bacterial community structure whose populations mostly belonged to the Alpha- and Gammaproteobacteria. A majority (>60%) of pufM sequences were affiliated to the Gammaproteobacteria reasserting that this class often represents the major component of the AAP bacterial community in oceanic regions. Two alphaproteobacterial groups dominate locally suggesting that they can constitute key players in this marine system transiently. We found that temperature is a major determinant of alpha diversity of AAP bacteria in this marine biome with specific clades emerging locally according to the partitioning of water masses. Whereas we expected specific AAP bacterial populations in this peculiar and newly explored ecosystem, most pufM sequences were highly related to sequences retrieved elsewhere. This observation highlights that the studied area does not favor AAP bacteria endemism but also opens new questions about the truthfulness of biogeographical patterns and on the extent of AAP bacterial diversity. PMID:26191046

  7. REGULAR PAPER Vertical distribution and characterization of aerobic phototrophic

    E-print Network

    REGULAR PAPER Vertical distribution and characterization of aerobic phototrophic bacteria the Juan de Fuca Ridge in the Pacific Ocean. Twelve similar strains of obligately aerobic phototrophic. Only one aerobic phototrophic strain was isolated from surface waters. This strain is morphologically

  8. Multicenter Evaluation of the Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Gram-Positive Aerobic Bacteria

    PubMed Central

    Burnham, Carey-Ann D.; Bythrow, Maureen; Garner, Omai B.; Ginocchio, Christine C.; Jennemann, Rebecca; Lewinski, Michael A.; Manji, Ryhana; Mochon, A. Brian; Procop, Gary W.; Richter, Sandra S.; Sercia, Linda; Westblade, Lars F.; Ferraro, Mary Jane; Branda, John A.

    2013-01-01

    Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF) is gaining momentum as a tool for bacterial identification in the clinical microbiology laboratory. Compared with conventional methods, this technology can more readily and conveniently identify a wide range of organisms. Here, we report the findings from a multicenter study to evaluate the Vitek MS v2.0 system (bioMérieux, Inc.) for the identification of aerobic Gram-positive bacteria. A total of 1,146 unique isolates, representing 13 genera and 42 species, were analyzed, and results were compared to those obtained by nucleic acid sequence-based identification as the reference method. For 1,063 of 1,146 isolates (92.8%), the Vitek MS provided a single identification that was accurate to the species level. For an additional 31 isolates (2.7%), multiple possible identifications were provided, all correct at the genus level. Mixed-genus or single-choice incorrect identifications were provided for 18 isolates (1.6%). Although no identification was obtained for 33 isolates (2.9%), there was no specific bacterial species for which the Vitek MS consistently failed to provide identification. In a subset of 463 isolates representing commonly encountered important pathogens, 95% were accurately identified to the species level and there were no misidentifications. Also, in all but one instance, the Vitek MS correctly differentiated Streptococcus pneumoniae from other viridans group streptococci. The findings demonstrate that the Vitek MS system is highly accurate for the identification of Gram-positive aerobic bacteria in the clinical laboratory setting. PMID:23658261

  9. INACTIVATION OF ENTERIC PATHOGENS DURING AEROBIC DIGESTION OF WASTEWATER SLUDGE

    EPA Science Inventory

    The effects of aerobic and anaerobic digestion on enteric viruses, enteric bacteria, total aerobic bacteria, and intestinal parasites were studied under laboratory and field conditions. Under laboratory conditions, the temperature of the sludge digestion was the major factor infl...

  10. Arsenate reduction and mobilization in the presence of indigenous aerobic bacteria obtained from high arsenic aquifers of the Hetao basin, Inner Mongolia.

    PubMed

    Guo, Huaming; Liu, Zeyun; Ding, Susu; Hao, Chunbo; Xiu, Wei; Hou, Weiguo

    2015-08-01

    Intact aquifer sediments were collected to obtain As-resistant bacteria from the Hetao basin. Two strains of aerobic As-resistant bacteria (Pseudomonas sp. M17-1 and Bacillus sp. M17-15) were isolated from the aquifer sediments. Those strains exhibited high resistances to both As(III) and As(V). Results showed that both strains had arr and ars genes, and led to reduction of dissolved As(V), goethite-adsorbed As(V), scorodite As(V) and sediment As(V), in the presence of organic carbon as the carbon source. After reduction of solid As(V), As release was observed from the solids to solutions. Strain M17-15 had a higher ability than strain M17-1 in reducing As(V) and promoting the release of As. These results suggested that the strains would mediate As(V) reduction to As(III), and thereafter release As(III), due to the higher mobility of As(III) in most aquifer systems. The processes would play an important role in genesis of high As groundwater. PMID:25863882

  11. Dai nippon printing co., ltd, Medi-Ca AC for enumeration of aerobic bacteria. Performance tested method 041302.

    PubMed

    Okochi, Norihiko; Yamazaki, Mamoru; Kiso, Shoichi; Kinoshita, Mai; Okita, Yurie; Kazama, Keisuke; Saito, Rui

    2014-01-01

    A ready-made dry medium method for aerobic count, the MediCa AC method, was compared to the AOAC Official Method 966.23, Microbiological Methods, for seven different heat-processed meat matrixes: cooked roast beef, Chinese barbecued pork (barbecued pork seasoned with honey-based sauce), bacon, cooked ham, frankfurter (made from beef and pork), and boiled and cooked pork sausage. The 95% confidence interval for the mean difference between the two methods at each contamination level for each matrix fell within the range of -0.50 to 0.50, and no statistical difference was observed at all three contamination levels for five matrixes. These results demonstrate that the Medi-Ca AC method is a reasonable alternative to the AOAC 966.23 method for cooked meat products. PMID:25051632

  12. Novel cellulose-binding domains, NodB homologues and conserved modular architecture in xylanases from the aerobic soil bacteria Pseudomonas fluorescens subsp. cellulosa and Cellvibrio mixtus.

    PubMed Central

    Millward-Sadler, S J; Davidson, K; Hazlewood, G P; Black, G W; Gilbert, H J; Clarke, J H

    1995-01-01

    To test the hypothesis that selective pressure has led to the retention of cellulose-binding domains (CBDs) by hemicellulase enzymes from aerobic bacteria, four new xylanase (xyn) genes from two cellulolytic soil bacteria, Pseudomonas fluorescens subsp. cellulosa and Cellvibrio mixtus, have been isolated and sequenced. Pseudomonas genes xynE and xynF encoded modular xylanases (XYLE and XYLF) with predicted M(r) values of 68,600 and 65000 respectively. XYLE contained a glycosyl hydrolase family 11 catalytic domain at its N-terminus, followed by three other domains; the second of these exhibited sequence identity with NodB from rhizobia. The C-terminal domain (40 residues) exhibited significant sequence identity with a non-catalytic domain of previously unknown function, conserved in all the cellulases and one of the hemicellulases previously characterized from the pseudomonad, and was shown to function as a CBD when fused to the reporter protein glutathione-S-transferase. XYLF contained a C-terminal glycosyl hydrolase family 10 catalytic domain and a novel CBD at its N-terminus. C. mixtus genes xynA and xynB exhibited substantial sequence identity with xynE and xynF respectively, and encoded modular xylanases with the same molecular architecture and, by inference, the same functional properties. In the absence of extensive cross-hybridization between other multiple cel (cellulase) and xyn genes from P. fluorescens subsp. cellulosa and genomic DNA from C. mixtus, similarity between the two pairs of xylanases may indicate a recent transfer of genes between the two bacteria. Images Figure 1 Figure 4 PMID:7492333

  13. Central role of dynamic tidal biofilms dominated by aerobic hydrocarbonoclastic bacteria and diatoms in the biodegradation of hydrocarbons in coastal mudflats.

    PubMed

    Coulon, Frédéric; Chronopoulou, Panagiota-Myrsini; Fahy, Anne; Païssé, Sandrine; Goñi-Urriza, Marisol; Peperzak, Louis; Acuña Alvarez, Laura; McKew, Boyd A; Brussaard, Corina P D; Underwood, Graham J C; Timmis, Kenneth N; Duran, Robert; McGenity, Terry J

    2012-05-01

    Mudflats and salt marshes are habitats at the interface of aquatic and terrestrial systems that provide valuable services to ecosystems. Therefore, it is important to determine how catastrophic incidents, such as oil spills, influence the microbial communities in sediment that are pivotal to the function of the ecosystem and to identify the oil-degrading microbes that mitigate damage to the ecosystem. In this study, an oil spill was simulated by use of a tidal chamber containing intact diatom-dominated sediment cores from a temperate mudflat. Changes in the composition of bacteria and diatoms from both the sediment and tidal biofilms that had detached from the sediment surface were monitored as a function of hydrocarbon removal. The hydrocarbon concentration in the upper 1.5 cm of sediments decreased by 78% over 21 days, with at least 60% being attributed to biodegradation. Most phylotypes were minimally perturbed by the addition of oil, but at day 21, there was a 10-fold increase in the amount of cyanobacteria in the oiled sediment. Throughout the experiment, phylotypes associated with the aerobic degradation of hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs) (Cycloclasticus) and alkanes (Alcanivorax, Oleibacter, and Oceanospirillales strain ME113), substantively increased in oiled mesocosms, collectively representing 2% of the pyrosequences in the oiled sediments at day 21. Tidal biofilms from oiled cores at day 22, however, consisted mostly of phylotypes related to Alcanivorax borkumensis (49% of clones), Oceanospirillales strain ME113 (11% of clones), and diatoms (14% of clones). Thus, aerobic hydrocarbon biodegradation is most likely to be the main mechanism of attenuation of crude oil in the early weeks of an oil spill, with tidal biofilms representing zones of high hydrocarbon-degrading activity. PMID:22407688

  14. Central Role of Dynamic Tidal Biofilms Dominated by Aerobic Hydrocarbonoclastic Bacteria and Diatoms in the Biodegradation of Hydrocarbons in Coastal Mudflats

    PubMed Central

    Coulon, Frédéric; Chronopoulou, Panagiota-Myrsini; Fahy, Anne; Païssé, Sandrine; Goñi-Urriza, Marisol; Peperzak, Louis; Acuña Alvarez, Laura; McKew, Boyd A.; Brussaard, Corina P. D.; Underwood, Graham J. C.; Timmis, Kenneth N.; Duran, Robert

    2012-01-01

    Mudflats and salt marshes are habitats at the interface of aquatic and terrestrial systems that provide valuable services to ecosystems. Therefore, it is important to determine how catastrophic incidents, such as oil spills, influence the microbial communities in sediment that are pivotal to the function of the ecosystem and to identify the oil-degrading microbes that mitigate damage to the ecosystem. In this study, an oil spill was simulated by use of a tidal chamber containing intact diatom-dominated sediment cores from a temperate mudflat. Changes in the composition of bacteria and diatoms from both the sediment and tidal biofilms that had detached from the sediment surface were monitored as a function of hydrocarbon removal. The hydrocarbon concentration in the upper 1.5 cm of sediments decreased by 78% over 21 days, with at least 60% being attributed to biodegradation. Most phylotypes were minimally perturbed by the addition of oil, but at day 21, there was a 10-fold increase in the amount of cyanobacteria in the oiled sediment. Throughout the experiment, phylotypes associated with the aerobic degradation of hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs) (Cycloclasticus) and alkanes (Alcanivorax, Oleibacter, and Oceanospirillales strain ME113), substantively increased in oiled mesocosms, collectively representing 2% of the pyrosequences in the oiled sediments at day 21. Tidal biofilms from oiled cores at day 22, however, consisted mostly of phylotypes related to Alcanivorax borkumensis (49% of clones), Oceanospirillales strain ME113 (11% of clones), and diatoms (14% of clones). Thus, aerobic hydrocarbon biodegradation is most likely to be the main mechanism of attenuation of crude oil in the early weeks of an oil spill, with tidal biofilms representing zones of high hydrocarbon-degrading activity. PMID:22407688

  15. Evaluation of the Removal of Indicator Bacteria from Domestic Sludge Processed by Autothermal Thermophilic Aerobic Digestion (ATAD)

    PubMed Central

    Piterina, Anna V.; Bartlett, John; Pembroke, Tony J.

    2010-01-01

    The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD) processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen) and fecal-coliform (indicator) densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing. PMID:20948933

  16. Genome Sequence of Virgibacillus pantothenticus DSM 26T (ATCC 14576), a Mesophilic and Halotolerant Bacterium Isolated from Soil

    PubMed Central

    Wang, Jie-ping; Liu, Guo-hong; Chen, De-ju; Zhu, Yu-jing; Chen, Zheng; Che, Jian-mei

    2015-01-01

    Virgibacillus pantothenticus DSM 26T is a Gram-positive, spore-forming, aerobic, mesophilic, and halotolerant bacterium. Here, we report its 4.76-Mb draft genome sequence, which is the first genome information of V. pantothenticus and will promote biological research and biotechnological application for the species. PMID:26383648

  17. Adequacy of Petrifilm™ Aerobic Count plates supplemented with de Man, Rogosa & Sharpe broth and chlorophenol red for enumeration of lactic acid bacteria in salami.

    PubMed

    de Castilho, Natália Parma Augusto; Okamura, Vivian Tiemi; Camargo, Anderson Carlos; Pieri, Fábio Alessandro; Nero, Luís Augusto

    2015-12-01

    The present study aimed to assess the performance of alternative protocols to enumerate lactic acid bacteria (LAB) in salami. Fourteen cultures and two mixed starter cultures were plated using six protocols: 1) Petrifilm™ Aerobic Count (AC) with MRS broth and chlorophenol red (CR), incubated under aerobiosis or 2) under anaerobiosis, 3) MRS agar with CR, 4) MRS agar with bromocresol purple, 5) MRS agar at pH5.7, and 6) All Purpose Tween agar. Samples of salami were obtained and the LAB microbiota was enumerated by plating according protocols 1, 2, 3 and 5. Regression analysis showed a significant correlation between the tested protocols, based on culture counts (p<0.05). Similar results were observed for salami, and no significant differences of mean LAB counts between selected protocols (ANOVA, p>0.05). Colonies were confirmed as LAB, indicating proper selectivity of the protocols. The results showed the adequacy of Petrifilm™ AC supplemented with CR for the enumeration of LAB in salami. PMID:26291606

  18. Screening and enumeration of lactic acid bacteria in milk using three different culture media in Petrifilm Aerobic Count plates and conventional pour plate methodology.

    PubMed

    Ortolani, Maria B T; Viçosa, Gabriela N; Beloti, Vanerli; Nero, Luís A

    2007-11-01

    This study aimed to compare Petrifilm Aerobic Count (AC) plates and the conventional pour plate methodology using de Mann-Rogosa-Sharpe (MRS), Kang-Fung (KF) and Kang-Fung-Sol (KFS) culture media for screening and enumeration of lactic acid bacteria (LAB) in milk. Suspensions of 10 LAB species in reconstituted powder skim milk and 30 raw milk samples, without experimental inoculation, were tested. For selective enumeration, all samples were previously diluted in MRS, KF and KFS broths and then plated in Petrifilm AC and conventional pour plate methodology, using the same culture media with added agar. All plates were incubated at 37 degrees C for 48 h in anaerobic conditions. Differences in the counts were observed only for raw milk samples using KFS in conventional methodology, when compared with the counts obtained from MRS and KF (P0.05). The results showed excellent correlation indexes between both methodologies using the three culture media for LAB suspensions (r=0.97 for MRS, KF and KFS). For raw milk samples, the correlation indexes were excellent (r=0.97, for MRS) and good (r=0.84 for KF, and r=0.82 for KFS), showing some interference in Petrifilm AC when supplements were added, especially lactic acid. These results indicate the possibility of using Petrifilm AC plates for enumeration of LAB in milk, even with the use of selective supplements. PMID:18005460

  19. Combined thermophilic aerobic process and conventional anaerobic digestion: effect on sludge biodegradation and methane production.

    PubMed

    Dumas, C; Perez, S; Paul, E; Lefebvre, X

    2010-04-01

    The efficiency of hyper-thermophilic (65 degrees Celsius) aerobic process coupled with a mesophilic (35 degrees Celsius) digester was evaluated for the activated sludge degradation and was compared to a conventional mesophilic digester. For two Sludge Retention Time (SRT), 21 and 42 days, the Chemical Oxygen Demand (COD) solubilisation and biodegradation processes, the methanisation yield and the aerobic oxidation were investigated during 180 days. The best results were obtained at SRT of 44 days; the COD removal yield was 30% higher with the Mesophilic Anaerobic Digestion/Thermophilic Aerobic Reactor (MAD-TAR) co-treatment. An increase of the sludge intrinsic biodegradability is also observed (20-40%), showing that the unbiodegradable COD in mesophilic conditions becomes bioavailable. However, the methanisation yield was quite similar for both processes at a same SRT. Finally, such a process enables to divide by two the volume of digester with an equivalent efficiency. PMID:19959355

  20. Dry matter and nutritional losses during aerobic deterioration of corn and sorghum silages as influenced by different lactic acid bacteria inocula.

    PubMed

    Tabacco, E; Righi, F; Quarantelli, A; Borreani, G

    2011-03-01

    The economic damage that results from aerobic deterioration of silage is a significant problem for farm profitability and feed quality. This paper quantifies the dry matter (DM) and nutritional losses that occur during the exposure of corn and sorghum silages to air over 14 d and assesses the possibility of enhancing the aerobic stability of silages through inoculation with lactic acid bacteria (LAB). The trial was carried out in Northern Italy on corn (50% milk line) and grain sorghum (early dough stage) silages. The crops were ensiled in 30-L jars, without a LAB inoculant (C), with a Lactobacillus plantarum inoculum (LP), and with a Lactobacillus buchneri inoculum (LB; theoretical rate of 1 × 10(6) cfu/g of fresh forage). The pre-ensiled material, the silage at silo opening, and the aerobically exposed silage were analyzed for DM content, fermentative profiles, yeast and mold count, starch, crude protein, ash, fiber components, 24-h and 48-h DM digestibility and neutral detergent fiber (NDF) degradability. The yield and nutrient analysis data of the corn and sorghum silages were used as input for Milk2006 to estimate the total digestible nutrients, net energy of lactation, and milk production per Mg of DM. The DM fermentation and respiration losses were also calculated. The inocula influenced the in vitro NDF digestibility at 24h, the net energy for lactation (NE(L)), and the predicted milk yield per megagram of DM, whereas the length of time of air exposure influenced DM digestibility at 24 and 48 h, the NE(L), and the predicted milk yield per megagram of DM in the corn silages. The inocula only influenced the milk yield per megagram of DM and the air exposure affected the DM digestibility at 24h, the NE(L), and the milk yield per megagram of DM in the sorghum silages. The milk yield, after 14 d of air exposure, decreased to 1,442, 1,418, and 1,277 kg/Mg of DM for C, LB, and LP corn silages, respectively, compared with an average value of 1,568 kg of silage at opening. In the sorghum silages, the milk yield, after 14 d of air exposure, decreased to 1,226, 1,278, and 1,250 kg/Mg of DM for C, LB, and LP, respectively. When the estimated milk yield per megagram of harvested DM of corn and sorghum silage were related to mold count, it was shown that the loss of potential milk production occurred when the mold count exceeded 4 log cfu/g of silage, and it was almost halved when the mold count reached values greater than 8 log cfu/g of silage. Inoculation with L. buchneri, at a rate of 1 × 10(6) cfu/g of fresh forage, enhanced the stability of the silage after exposure to air, and, consequently, contributed to maintaining the nutritional value of the harvested forage over time, for air exposure up to 7 d. PMID:21338806

  1. A RAPD based study revealing a previously unreported wide range of mesophilic and thermophilic spore formers associated with milk powders in China.

    PubMed

    Sadiq, Faizan A; Li, Yun; Liu, TongJie; Flint, Steve; Zhang, Guohua; He, GuoQing

    2016-01-18

    Aerobic spore forming bacteria are potential milk powder contaminants and are viewed as indicators of poor quality. A total of 738 bacteria, including both mesophilic and thermophilic, isolated from twenty-five powdered milk samples representative of three types of milk powders in China were analyzed based on the random amplified polymorphic DNA (RAPD) protocol to provide insight into species diversity. Bacillus licheniformis was found to be the most prevalent bacterium with greatest diversity (~43% of the total isolates) followed by Geobacillus stearothermophilus (~21% of the total isolates). Anoxybacillus flavithermus represented only 8.5% of the total profiles. Interestingly, actinomycetes represented a major group of the isolates with the predominance of Laceyella sacchari followed by Thermoactinomyces vulgaris, altogether comprising of 7.3% of the total isolates. Out of the nineteen separate bacterial species (except five unidentified groups) recovered and identified from milk powders, twelve proved to belong to novel or previously unreported species in milk powders. Assessment and characterization of the harmful effects caused by this particular micro-flora on the quality and safety of milk powders will be worth doing in the future. PMID:26555161

  2. (Per)Chlorate-Reducing Bacteria Can Utilize Aerobic and Anaerobic Pathways of Aromatic Degradation with (Per)Chlorate as an Electron Acceptor

    PubMed Central

    Carlström, Charlotte I.; Loutey, Dana; Bauer, Stefan; Clark, Iain C.; Rohde, Robert A.; Iavarone, Anthony T.; Lucas, Lauren

    2015-01-01

    ABSTRACT The pathways involved in aromatic compound oxidation under perchlorate and chlorate [collectively known as (per)chlorate]-reducing conditions are poorly understood. Previous studies suggest that these are oxygenase-dependent pathways involving O2 biogenically produced during (per)chlorate respiration. Recently, we described Sedimenticola selenatireducens CUZ and Dechloromarinus chlorophilus NSS, which oxidized phenylacetate and benzoate, two key intermediates in aromatic compound catabolism, coupled to the reduction of perchlorate or chlorate, respectively, and nitrate. While strain CUZ also oxidized benzoate and phenylacetate with oxygen as an electron acceptor, strain NSS oxidized only the latter, even at a very low oxygen concentration (1%, vol/vol). Strains CUZ and NSS contain similar genes for both the anaerobic and aerobic-hybrid pathways of benzoate and phenylacetate degradation; however, the key genes (paaABCD) encoding the epoxidase of the aerobic-hybrid phenylacetate pathway were not found in either genome. By using transcriptomics and proteomics, as well as by monitoring metabolic intermediates, we investigated the utilization of the anaerobic and aerobic-hybrid pathways on different electron acceptors. For strain CUZ, the results indicated utilization of the anaerobic pathways with perchlorate and nitrate as electron acceptors and of the aerobic-hybrid pathways in the presence of oxygen. In contrast, proteomic results suggest that strain NSS may use a combination of the anaerobic and aerobic-hybrid pathways when growing on phenylacetate with chlorate. Though microbial (per)chlorate reduction produces molecular oxygen through the dismutation of chlorite (ClO2?), this study demonstrates that anaerobic pathways for the degradation of aromatics can still be utilized by these novel organisms. PMID:25805732

  3. Searching for mesophilic Thermotogales bacteria: "mesotogas" in the wild.

    PubMed

    Nesbø, Camilla L; Kumaraswamy, Rajkumari; Dlutek, Marlena; Doolittle, W Ford; Foght, Julia

    2010-07-01

    All cultivated Thermotogales are thermophiles or hyperthermophiles. However, optimized 16S rRNA primers successfully amplified Thermotogales sequences from temperate hydrocarbon-impacted sites, mesothermic oil reservoirs, and enrichment cultures incubated at <46 degrees C. We conclude that distinct Thermotogales lineages commonly inhabit low-temperature environments but may be underreported, likely due to "universal" 16S rRNA gene primer bias. PMID:20495053

  4. Aerobic and Anaerobic Metabolism Aerobic = oxidative metabolism

    E-print Network

    Jodice, Patrick

    Aerobic and Anaerobic Metabolism · Aerobic = oxidative metabolism ­ 1 mol glucose CO2 and H20, 36 are disrupted · All activity in vertebrates is aerobic ­ anaerobiosis in vertebrates is just aerobiosis and velocity (F9.9) From McNab 2002. #12;Locomotion in Reptiles · Aerobic scope appears to vary among taxa

  5. Effect of sand and shaking duration on the recovery of aerobic bacteria, coliforms, and Escherichia coli from prechill broiler whole carcass rinsates.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experiment was conducted to determine the effect of added sand and shaking duration on the recovery of bacteria from broiler carcasses using the whole carcass rinse (WCR) method. In each of 4 replications, 12 eviscerated broiler carcasses were obtained from a commercial processing plant prior to ...

  6. The aerobic and anaerobic bacteriology of perirectal abscesses.

    PubMed Central

    Brook, I; Frazier, E H

    1997-01-01

    The microbiology of perirectal abscesses in 144 patients was studied. Aerobic or facultative bacteria only were isolated in 13 (9%) instances, anaerobic bacteria only were isolated in 27 (19%) instances, and mixed aerobic and anaerobic flora were isolated in 104 (72%) instances. A total of 325 anaerobic and 131 aerobic or facultative isolates were recovered (2.2 anaerobic isolates and 0.9 aerobic isolates per specimen). The predominant anaerobes were as follows: Bacteroides fragilis group (85 isolates), Peptostreptococcus spp. (72 isolates), Prevotella spp. (71 isolates), Fusobacterium spp. (21 isolates), Porphyromonas spp. (20 isolates), and Clostridium spp. (15 isolates). The predominant aerobic and facultative bacteria were as follows: Staphylococcus aureus (34 isolates), Streptococcus spp. (28 isolates), and Escherichia coli (19 isolates). These data illustrate the polymicrobial aerobic and anaerobic microbiology of perirectal abscesses. PMID:9350771

  7. What Is Aerobic Dancing?

    MedlinePLUS

    ... Footwear Artices & Resources Photos Contact Us Members Only Aerobic Dancing What is Aerobic Dancing? Based on a document produced in cooperation ... Association From humble beginnings in the late 1960s, aerobic dance has become a major symbol of the ...

  8. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience.

    PubMed

    Niu, Qigui; Takemura, Yasuyuki; Kubota, Kengo; Li, Yu-You

    2015-09-01

    While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000mg/L with free ammonia (FA) 2000mg/L compared to 16,000mg/L (FA1500mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gVSin in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages. PMID:26054964

  9. Prevalence of bacteria and absence of anisakid parasites in raw and prepared fish and seafood dishes in Spanish restaurants.

    PubMed

    Sospedra, I; Rubert, J; Soriano, J M; Mañes, J; Fuentes, M V

    2015-03-01

    This study evaluated the presence of bacteria and anisakid parasites in 45 samples of raw anchovies in vinegar, a dish widely eaten in Spain, and in 227 samples of cooked fish and cephalopods served in Spanish food service establishments. Our analysis showed that, according to European and Spanish regulation, 14 to 30% of the prepared fish and cephalopod dishes exceeded the maximum allowable level for mesophilic aerobic counts, and 10 to 40% of these samples exceeded the allowable levels for Enterobacteriaceae. None of the studied samples showed evidence of anisakid parasites, Escherichia coli, Staphylococcus aureus, Salmonella, or Listeria monocytogenes. These results indicate that application of hazard analysis and critical control points, food safety training courses, and routine inspections in compliance with current European and Spanish legislation help protect consumer health. PMID:25719890

  10. [Comparative characteristics of free-living ultramicroscopical bacteria obtained from extremal biotopes].

    PubMed

    Suzina, N E; Esikova, T Z; Oleinikov, R R; Gafarov, B; Shorokhov, A P; Polivtseva, V N; Ross, D V; Abashina, T N; Duda, V I; Boronin, A M

    2015-01-01

    We isolated 50 strains of free-living ultrasmall bacteria with a cell volume that varies from 0.02 to 1.3 microm3 from a range of extremal natural biotopes, namely permafrost soils, oil slime, soils, lake silt, thermal swamp moss, and the skin integuments of the clawed frog, Xenopus laevis. Of them, 15 isolates, characterized by a cell size of less than 0.1 microm3 and a genome size from 1.5 to 2.4 Mb, were subsumed to ultramicrobacteria belonging to different philogenetic groups (Alphaproteobacteria, Bacteroidetes, Actinobacteria) and genera (Kaistia, Chryseobacterium, Microbacterium, Leucobacter, Leifsonia, and Agrococcus) of the Bacteria domain. They are free-living mesophilic heterotrophic aerobic bacteria. The representatives of Kaistia and Chryseobacterium genera were capable of facultative parasitism on other species of chemo-organotrophic bacteria and cyanobacteria. The ultramicrobacteria differed in their morpholgy, cell ultrastructural organization, and physiological and biochemical features. According to the fine structure of their cell walls, the isolates were subdivided into two groups, namely Gram-positive and Gram-negative forms. PMID:26027350

  11. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    SciTech Connect

    Coyne, P.; Smith, G.

    1995-08-15

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

  12. Isolation and characterization of bacteriocinogenic lactic bacteria from M-Tuba and Tepache, two traditional fermented beverages in México.

    PubMed

    de la Fuente-Salcido, Norma M; Castañeda-Ramírez, José Cristobal; García-Almendárez, Blanca E; Bideshi, Dennis K; Salcedo-Hernández, Rubén; Barboza-Corona, José E

    2015-09-01

    Mexican Tuba (M-Tuba) and Tepache are Mexican fermented beverages prepared mainly with pineapple pulp and coconut palm, respectively. At present, reports on the microbiota and nutritional effects of both beverages are lacking. The purpose of this study was to determine whether M-Tuba and Tepache contain cultivable lactic acid bacteria (LAB) capable of producing bacteriocins. Tepache and M-Tuba contain mesophilic aerobic bacteria, LAB, and yeast. Bacillus subtilis, Listeria monocytogenes, Listeria innocua, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, and Salmonella spp, were the microorganisms most susceptible to metabolites produced by bacterial isolates. M-Tuba and Tepache contain bacteria that harbor genes coding for nisin and enterocin, but not pediocin. The presence of Lactococcus lactis and E. faecium in M-Tuba and Tepache, was identified by 16S rDNA. These bacteria produced bacteriocins of ?3.5 kDa and 4.0-4.5 kDa, respectively. Partial purified bacteriocins showed inhibitory effect against Micrococcus luteus, L. monocytogenes, L. innocua, Str. agalactiae, S. aureus, Bacillus cereus, B. subtilis, E. faecalis, and K. pneumoniae. We characterized, for the first time, cultivable microbiota of M-Tuba and Tepache, and specifically, identified candidate lactic bacteria (LAB) present in these beverages that were capable of synthesizing antimicrobial peptides, which collectively could provide food preservative functions. PMID:26405529

  13. Isolation and characterization of bacteriocinogenic lactic bacteria from M-Tuba and Tepache, two traditional fermented beverages in México

    PubMed Central

    de la Fuente-Salcido, Norma M; Castañeda-Ramírez, José Cristobal; García-Almendárez, Blanca E; Bideshi, Dennis K; Salcedo-Hernández, Rubén; Barboza-Corona, José E

    2015-01-01

    Mexican Tuba (M-Tuba) and Tepache are Mexican fermented beverages prepared mainly with pineapple pulp and coconut palm, respectively. At present, reports on the microbiota and nutritional effects of both beverages are lacking. The purpose of this study was to determine whether M-Tuba and Tepache contain cultivable lactic acid bacteria (LAB) capable of producing bacteriocins. Tepache and M-Tuba contain mesophilic aerobic bacteria, LAB, and yeast. Bacillus subtilis, Listeria monocytogenes, Listeria innocua, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, and Salmonella spp, were the microorganisms most susceptible to metabolites produced by bacterial isolates. M-Tuba and Tepache contain bacteria that harbor genes coding for nisin and enterocin, but not pediocin. The presence of Lactococcus lactis and E. faecium in M-Tuba and Tepache, was identified by 16S rDNA. These bacteria produced bacteriocins of ?3.5 kDa and 4.0–4.5 kDa, respectively. Partial purified bacteriocins showed inhibitory effect against Micrococcus luteus, L. monocytogenes, L. innocua, Str. agalactiae, S. aureus, Bacillus cereus, B. subtilis, E. faecalis, and K. pneumoniae. We characterized, for the first time, cultivable microbiota of M-Tuba and Tepache, and specifically, identified candidate lactic bacteria (LAB) present in these beverages that were capable of synthesizing antimicrobial peptides, which collectively could provide food preservative functions. PMID:26405529

  14. Natural Hot Spots for Gain of Multiple Resistances: Arsenic and Antibiotic Resistances in Heterotrophic, Aerobic Bacteria from Marine Hydrothermal Vent Fields

    PubMed Central

    Farias, Pedro; Espírito Santo, Christophe; Branco, Rita; Francisco, Romeu; Santos, Susana; Hansen, Lars; Sorensen, Soren

    2015-01-01

    Microorganisms are responsible for multiple antibiotic resistances that have been associated with resistance/tolerance to heavy metals, with consequences to public health. Many genes conferring these resistances are located on mobile genetic elements, easily exchanged among phylogenetically distant bacteria. The objective of the present work was to isolate arsenic-, antimonite-, and antibiotic-resistant strains and to determine the existence of plasmids harboring antibiotic/arsenic/antimonite resistance traits in phenotypically resistant strains, in a nonanthropogenically impacted environment. The hydrothermal Lucky Strike field in the Azores archipelago (North Atlantic, between 11°N and 38°N), at the Mid-Atlantic Ridge, protected under the OSPAR Convention, was sampled as a metal-rich pristine environment. A total of 35 strains from 8 different species were isolated in the presence of arsenate, arsenite, and antimonite. ACR3 and arsB genes were amplified from the sediment's total DNA, and 4 isolates also carried ACR3 genes. Phenotypic multiple resistances were found in all strains, and 7 strains had recoverable plasmids. Purified plasmids were sequenced by Illumina and assembled by EDENA V3, and contig annotation was performed using the “Rapid Annotation using the Subsystems Technology” server. Determinants of resistance to copper, zinc, cadmium, cobalt, and chromium as well as to the antibiotics ?-lactams and fluoroquinolones were found in the 3 sequenced plasmids. Genes coding for heavy metal resistance and antibiotic resistance in the same mobile element were found, suggesting the possibility of horizontal gene transfer and distribution of theses resistances in the bacterial population. PMID:25636836

  15. Natural hot spots for gain of multiple resistances: arsenic and antibiotic resistances in heterotrophic, aerobic bacteria from marine hydrothermal vent fields.

    PubMed

    Farias, Pedro; Espírito Santo, Christophe; Branco, Rita; Francisco, Romeu; Santos, Susana; Hansen, Lars; Sorensen, Soren; Morais, Paula V

    2015-04-01

    Microorganisms are responsible for multiple antibiotic resistances that have been associated with resistance/tolerance to heavy metals, with consequences to public health. Many genes conferring these resistances are located on mobile genetic elements, easily exchanged among phylogenetically distant bacteria. The objective of the present work was to isolate arsenic-, antimonite-, and antibiotic-resistant strains and to determine the existence of plasmids harboring antibiotic/arsenic/antimonite resistance traits in phenotypically resistant strains, in a nonanthropogenically impacted environment. The hydrothermal Lucky Strike field in the Azores archipelago (North Atlantic, between 11°N and 38°N), at the Mid-Atlantic Ridge, protected under the OSPAR Convention, was sampled as a metal-rich pristine environment. A total of 35 strains from 8 different species were isolated in the presence of arsenate, arsenite, and antimonite. ACR3 and arsB genes were amplified from the sediment's total DNA, and 4 isolates also carried ACR3 genes. Phenotypic multiple resistances were found in all strains, and 7 strains had recoverable plasmids. Purified plasmids were sequenced by Illumina and assembled by EDENA V3, and contig annotation was performed using the "Rapid Annotation using the Subsystems Technology" server. Determinants of resistance to copper, zinc, cadmium, cobalt, and chromium as well as to the antibiotics ?-lactams and fluoroquinolones were found in the 3 sequenced plasmids. Genes coding for heavy metal resistance and antibiotic resistance in the same mobile element were found, suggesting the possibility of horizontal gene transfer and distribution of theses resistances in the bacterial population. PMID:25636836

  16. Research paper Aerobic biomineralization of Mg-rich carbonates: Implications for

    E-print Network

    Gilli, Adrian

    Research paper Aerobic biomineralization of Mg-rich carbonates: Implications for natural-rich carbonates Dolomite Huntite Halophilic aerobic bacteria Stable carbon isotope We studied the formation of Mg-rich carbonate in culture experiments using different aerobic bacterial strains and aqueous Mg/Ca ratios (2 to 11

  17. LETTER doi:10.1038/nature10511 Aerobic bacterial pyrite oxidation and acid rock

    E-print Network

    Konhauser, Kurt

    LETTER doi:10.1038/nature10511 Aerobic bacterial pyrite oxidation and acid rock drainage during stable crustal pyrite reservoir by aerobic-respiring, chemolithoau- totrophic bacteria could have known geochemical evidence for acidophilic aerobes and the resulting acid rock drain- age, and accounts

  18. Aerobic exercise (image)

    MedlinePLUS

    Aerobic exercise gets the heart working to pump blood through the heart more quickly and with more ... must be oxygenated more quickly, which quickens respiration. Aerobic exercise strengthens the heart and boosts healthy cholesterol ...

  19. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  20. STUDIES OF METHANOGENIC BACTERIA IN SLUDGE

    EPA Science Inventory

    Methanogenic bacteria were isolated from mesophilic anaerobic digesters. The isolates were able to utilize H2 and CO2 acetate, formate and methanol, but were not able to metabolize propionate and butyrate. It was shown the propionate and butyrate are not substrates for methanogen...

  1. Identification of hopanoid, sterol, and tetrahymanol production in the aerobic methanotroph Methylomicrobium alcaliphilum 20Z

    NASA Astrophysics Data System (ADS)

    Welander, P. V.; Summons, R. E.

    2013-12-01

    Correlating the occurrence of molecular biosignatures preserved in the rock record with specific microbial taxa is a compelling strategy for studying microbial life in the context of the Earth's distant past. Polycyclic triterpenoids, including the hopanes and steranes, comprise classes of biomarkers that are readily detected in a variety of ancient sediments and are clearly recognized as the diagenetic products of modern day bacterial hopanoids and eukaryotic sterols. Thus, based on the distribution of these lipids in extant microbes, the occurrence of their diagenetic products in the rock record is often utilized as evidence for the existence of specific bacterial and eukaryotic taxa in ancient ecosystems. However, questions have arisen about our understanding of the taxonomic distribution of many of these molecular biomarkers in extant microbes. This is prompting reassessments of the use of polycyclic triterpenoids as geological proxies for microbial taxa, especially in the light of the poorly defined issue of microbial diversity. Recently, significant effort has been put forth to better understand the biosynthesis, function, and regulation of these lipid molecules in a variety of modern organisms so that a more informed interpretation of their occurrence in the rock record can be reached. Here we report the unprecedented production of three different classes of polycyclic triterpenoid biomarker lipids in one bacterium. Methylomicrobium alcaliphilum 20Z, a member of the Gammaproteobacteria, is a halotolerant alkaliphilic aerobic methanotroph previously isolated from a moderately saline soda lake in Tuva (Central Asia). In this study, M. alcaliphilum is shown to produce C-3 methylated and unmethylated aminohopanoids commonly associated with other mesophilic aerobic methanotrophs. In addition, this organism is also able to produce 4,4-dimethyl sterols and surprisingly, the gammacerane triterpenoid tetrahymanol. Previously, tetrahymanol production has only been observed in freshwater and marine ciliates (such as Tetrahymena thermophila) and two bacteria unrelated to aerobic methanotrophs, Rhodopseudomonas and Bradyrhizobium. Utilizing comparative genomics we identified the oxidosqualene cyclase gene required for sterol biosynthesis as well as two copies of the squalene hopene cyclase gene necessary for hopanoid biosynthesis in the M. alcaliphilum genome. To determine if one or both copies of the squalene hopene cyclase gene were necessary for aminohopanoid or tetrahymanol production, shc gene deletions were constructed and the subsequent mutants were analyzed for impaired hopanoid production. The occurrence of sterols, hopanoids and gammacerane lipids in one bacterium not only provides a unique system in which to study the biosynthesis and function of each lipid class but also to investigate any potential functional and evolutionary relationship these three lipid classes may share. In turn, these studies provide information necessary to properly interpret the occurrence of these molecules in the rock record.

  2. Model of the sewage sludge-straw composting process integrating different heat generation capacities of mesophilic and thermophilic microorganisms.

    PubMed

    Bia?obrzewski, I; Mikš-Krajnik, M; Dach, J; Markowski, M; Czeka?a, W; G?uchowska, K

    2015-09-01

    A mathematical model integrating 11 first-order differential equations describing the dynamics of the aerobic composting process of sewage sludge was proposed. The model incorporates two microbial groups (mesophiles and thermophiles) characterized by different capacities of heat generation. Microbial growth rates, heat and mass transfer and degradation kinetics of the sewage sludge containing straw were modeled over a period of 36days. The coefficients of metabolic heat generation for mesophiles were 4.32×10(6) and 6.93×10(6)J/kg, for winter and summer seasons, respectively. However, for thermophiles, they were comparable for both seasons reaching 10.91×10(6) and 10.51×10(6)J/kg. In the model, significant parameters for microbial growth control were temperature and the content of easily hydrolysable substrate. The proposed model provided a satisfactory fit to experimental data captured for cuboid-shaped bioreactors with forced aeration. Model predictions of specific microbial populations and substrate decomposition were crucial for accurate description and understanding of sewage sludge composting. PMID:26087644

  3. [Isolation and identification of electrochemically active microorganism from micro-aerobic environment].

    PubMed

    Wu, Song; Xiao, Yong; Zheng, Zhi-Yong; Zheng, Yue; Yang, Zhao-Hui; Zhao, Feng

    2014-10-01

    Extracellular electron transfer of electrochemically active microorganism plays vital role in biogeochemical cycling of metals and carbon and in biosynthesis of bioenergy. Compared to anaerobic anode, micro-aerobic anode captures more energy from microbial fuel cell. However, most of previous researches focused on functioning bacteria in anaerobic anode, functioning bacteria in micro-aerobic anode was rarely studied. Herein, we used the traditional aerobic screening technology to isolate functioning bacteria from a micro-aerobic anode. Three pure cultures Aeromonas sp. WS-XY2, Citrobacter sp. WS-XY3 and Bacterium strain WS-XY4 were obtained. WS-XY2 and WS-XY3 were belonged to Proteobacteria, whereas WS-XY4 was possibly a new species. Cyclic voltammetry and chronoamperometry analysis demonstrated all of them showed the electrochemical activity by direct extracellular electron transfer, and micro-aerobic anode could select bacteria that have similar electrochemical activity to proliferate on the anode. We further conclude that functioning bacteria in micro-aerobic anode are more efficient than that of anaerobic anode may be the reason that micro-aerobic anode has better performance than anaerobic anode. Therefore, a thorough study of functioning bacteria in micro-aerobic anode will significantly promote the energy recovery from microbial fuel cell. PMID:25693404

  4. Essential oils against foodborne pathogens and spoilage bacteria in minced meat.

    PubMed

    Barbosa, Lidiane Nunes; Rall, Vera Lucia Mores; Fernandes, Ana Angélica Henrique; Ushimaru, Priscila Ikeda; da Silva Probst, Isabella; Fernandes, Ary

    2009-01-01

    The antimicrobial activity of essential oils of oregano, thyme, basil, marjoram, lemongrass, ginger, and clove was investigated in vitro by agar dilution method and minimal inhibitory concentration (MIC) determination against Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative strains (Escherichia coli and Salmonella Enteritidis). MIC(90%) values were tested against bacterial strains inoculated experimentally in irradiated minced meat and against natural microbiota (aerobic or facultative, mesophilic, and psychrotrophic bacteria) found in minced meat samples. MIC(90%) values ranged from 0.05%v/v (lemongrass oil) to 0.46%v/v (marjoram oil) to Gram-positive bacteria and from 0.10%v/v (clove oil) to 0.56%v/v (ginger oil) to Gram-negative strains. However, the MIC(90%) assessed on minced meat inoculated experimentally with foodborne pathogen strains and against natural microbiota of meat did not show the same effectiveness, and 1.3 and 1.0 were the highest log CFU/g reduction values obtained against tested microorganisms. PMID:19580445

  5. Comparison of the microbial communities in solid-state anaerobic digestion (SS-AD) reactors operated at mesophilic and thermophilic temperatures.

    PubMed

    Li, Yueh-Fen; Nelson, Michael C; Chen, Po-Hsu; Graf, Joerg; Li, Yebo; Yu, Zhongtang

    2015-01-01

    The microbiomes involved in liquid anaerobic digestion process have been investigated extensively, but the microbiomes underpinning solid-state anaerobic digestion (SS-AD) are poorly understood. In this study, microbiome composition and temporal succession in batch SS-AD reactors, operated at mesophilic or thermophilic temperatures, were investigated using Illumina sequencing of 16S rRNA gene amplicons. A greater microbial richness and evenness were found in the mesophilic than in the thermophilic SS-AD reactors. Firmicutes accounted for 60 and 82 % of the total Bacteria in the mesophilic and in the thermophilic SS-AD reactors, respectively. The genus Methanothermobacter dominated the Archaea in the thermophilic SS-AD reactors, while Methanoculleus predominated in the mesophilic SS-AD reactors. Interestingly, the data suggest syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis as an important pathway for biogas production during the thermophilic SS-AD. Canonical correspondence analysis (CCA) showed that temperature was the most influential factor in shaping the microbiomes in the SS-AD reactors. Thermotogae showed strong positive correlation with operation temperature, while Fibrobacteres, Lentisphaerae, Spirochaetes, and Tenericutes were positively correlated with daily biogas yield. This study provided new insight into the microbiome that drives SS-AD process, and the findings may help advance understanding of the microbiome in SS-AD reactors and the design and operation of SS-AD systems. PMID:25194839

  6. Treatment of organic synthesis wastewater using anaerobic packed bed and aerobic suspended growth bioreactors.

    PubMed

    Mijaylova-Nacheva, P; Ramírez-Camperos, E; Cuevas-Velasco, S

    2007-01-01

    The performance of an anaerobic mesophilic packed bed reactor, with a mixture of GAC and tezontle, followed by an aerobic suspended growth system was studied for the treatment of organic chemical wastewater with a high COD concentration (22-29 g/L). The testing of the anaerobic-aerobic system was conducted in an experimental set-up for almost 2.5 years. Different operational conditions were evaluated. The anaerobic reactor showed performance stability and COD removals higher than 80% were obtained with loads up to 16.6 kg x m(-3) x d(-1). The acclimation of the aerobic biomass to the substrate in the anaerobic effluent was very quick and COD removals higher than 94% were obtained even at high organic loads. The combined anaerobic-aerobic system allowed total COD removals higher than 99.5% and the accomplishment of the discharge requirements of 200 mgCOD/L when the anaerobic reactor was operated with loads of 8-11 kg x m(-3)x d(-1) and the aerobic reactor with 0.33 kg x kg(-1) x d(-1), being the total HRT of 4.4. The average TKN removal in the anaerobic-aerobic system was 97%, the average for the anaerobic reactor being 52% and that one for the aerobic system being 94%. PMID:17506443

  7. Microbiological quality of ready-to-eat salads: an underestimated vehicle of bacteria and clinically relevant antibiotic resistance genes.

    PubMed

    Campos, Joana; Mourão, Joana; Pestana, Nazaré; Peixe, Luísa; Novais, Carla; Antunes, Patrícia

    2013-09-16

    The increase demand for fresh vegetables is causing an expansion of the market for minimally processed vegetables along with new recognized food safety problems. To gain further insight on this topic we analyzed the microbiological quality of Portuguese ready-to-eat salads (RTS) and their role in the spread of bacteria carrying acquired antibiotic resistance genes, food products scarcely considered in surveillance studies. A total of 50 RTS (7 brands; split or mixed leaves, carrot, corn) were collected in 5 national supermarket chains in Porto region (2010). They were tested for aerobic mesophilic counts, coliforms and Escherichia coli counts as well as for the presence of Salmonella and Listeria monocytogenes. Samples were also plated in different selective media with/without antibiotics before and after enrichment. The E. coli, other coliforms and Enterococcus recovered were characterized for antibiotic resistance profiles and clonality with phenotypic and genetic approaches. A high number of RTS presented poor microbiological quality (86%--aerobic mesophilic counts, 74%--coliforms, 4%--E. coli), despite the absence of screened pathogens. In addition, a high diversity of bacteria (species and clones) and antibiotic resistance backgrounds (phenotypes and genotypes) were observed, mostly with enrichment and antibiotic selective media. E. coli was detected in 13 samples (n=78; all types and 4 brands; phylogenetic groups A, B1 and D; none STEC) with resistance to tetracycline [72%; tet(A) and/or tet(B)], streptomycin (58%; aadA and/or strA-strB), sulfamethoxazole (50%; sul1 and/or sul2), trimethoprim (50%; dfrA1 or dfrA12), ampicillin (49%; blaTEM), nalidixic acid (36%), ciprofloxacin (5%) or chloramphenicol (3%; catA). E. coli clones, including the widespread group D/ST69, were detected in different samples from the same brand or different brands pointing out to a potential cross-contamination. Other clinically relevant resistance genes were detected in 2 Raoultella terrigena carrying a bla(SHV-2) and 1 Citrobacter freundii isolate with a qnrB9 gene. Among Enterococcus (n=108; 35 samples; Enterococcus casseliflavus--40, Enterococcus faecalis--20, Enterococcus faecium--18, Enterococcus hirae--9, Enterococcus gallinarum--5, and Enterococcus spp.--16) resistance was detected for tetracyclines [6%; tet(M) and/or tet(L)], erythromycin [3%; erm(B)], nitrofurantoin (1%) or ciprofloxacin (1%). The present study places ready-to-eat salads within the spectrum of ecological niches that may be vehicles for antibiotic resistance bacteria/genes with clinical interest (e.g. E. coli-D-ST69; bla(SHV-2)) and these findings are worthy of attention as their spread to humans by ingestion cannot be dismissed. PMID:24036261

  8. Aerobic Conditioning Class.

    ERIC Educational Resources Information Center

    Johnson, Neil R.

    1980-01-01

    An aerobic exercise class that focuses on the conditioning of the cardiovascular and muscular systems is presented. Students complete data cards on heart rate, pulse, and exercises to be completed during the forty minute course. (CJ)

  9. ARTICLE IN PRESS Maltodextrin-binding proteins from diverse bacteria and archaea are

    E-print Network

    ARTICLE IN PRESS U N C O R R EC TED PR O O F Maltodextrin-binding proteins from diverse bacteria Escherichia coli maltose-binding protein (MBP) is 10 frequently used as an a/nity tag to facilitate the puri organisms including both mesophilic and thermophilic bacteria 15 and archaea. In the present study, we

  10. Effect of high pressure on mesophilic lactic fermentation streptococci

    NASA Astrophysics Data System (ADS)

    Reps, A.; Ku?micka, M.; Wi?niewska, K.

    2008-07-01

    The research concerned the effect of high pressure on mesophilic lactic fermentation streptococci, present in two cheese-making commercial inocula produced by Christian-Hansen. Water solutions of inocula were pressurized at 50-800 MPa, at room temperature, for 30-120 min. Pressurization at 50-100 MPa slightly increased or reduced the number of lactic streptococci, depending on the inoculum and pressurization time. Pressurization at 200 MPa caused a reduction in the number of streptococci by over 99.9%, whereas the pressure of 400 MPa and above almost completely inactivated streptococci. Pressurization also reduced the dynamics of microorganism growth and acidification, to the degree depending on the pressure.

  11. Factors affecting decay of Salmonella Birkenhead and coliphage MS2 during mesophilic anaerobic digestion and air drying of sewage sludge.

    PubMed

    Mondal, Tania; Rouch, Duncan A; Thurbon, Nerida; Smith, Stephen R; Deighton, Margaret A

    2015-06-01

    Factors affecting the decay of Salmonella Birkenhead and coliphage, as representatives of bacterial and viral pathogens, respectively, during mesophilic anaerobic digestion (MAD) and air drying treatment of anaerobically digested sewage sludge were investigated. Controlled concentrations of S. Birkenhead were inoculated into non-sterile, autoclaved, ?-irradiated and nutrient-supplemented sludge and cultures were incubated at 37 °C (MAD sludge treatment temperature) or 20 °C (summer air drying sludge treatment temperature). Nutrient limitation caused by microbial competition was the principal mechanism responsible for the decay of S. Birkenhead by MAD and during air drying of digested sludge. The effects of protease activity in sludge on MS2 coliphage decay in digested and air dried sludge were also investigated. MS2 coliphage showed a 3.0-3.5 log10 reduction during incubation with sludge-protease extracts at 37 °C for 25 h. Proteases produced by indigenous microbes in sludge potentially increase coliphage inactivation and may therefore have a significant role in the decay of enteric viruses in sewage sludge. The results help to explain the loss of viability of enteric bacteria and viral pathogens with treatment process time and contribute to fundamental understanding of the various biotic inactivation mechanisms operating in sludge treatment processes at mesophilic and ambient temperatures. PMID:26042978

  12. Aerobic and anaerobic cecal bacterial flora of commercially processed broilers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Differences in the bacterial flora of aerobic and anaerobic cultures of broiler ceca collected from a commercial poultry processing facility were determined. Bacterial isolates from cecal cultures were selected based on the ability of the bacteria to grow in media supplemented with lactate and succ...

  13. Managing for Improved Aerobic Stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic deterioration or spoilage of silage is the result of aerobic microorganisms metabolizing components of the silage using oxygen. In the almost 40 years over which these silage conferences have been held, we have come to recognize the typical pattern of aerobic microbial development by which s...

  14. Sulfate- and Sulfur-Reducing Bacteria as Terrestrial Analogs for Microbial Life on Jupiter's Satellite Io

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.; Six, N. Frank (Technical Monitor)

    2001-01-01

    Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Io to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of Io. There are extreme temperature variations on Io's surface, ranging from -130 C to over 2000 C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Io. Hence Io may have great significance to Astrobiology. Earth's life forms that depend on sulfur respiration are members of two domains: Bacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: 1) the sulfur oxidizing process (occurring at aerobic conditions) and 2) the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, arsenate, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorine-containing phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs, deepsea hydrothermal vents, soda and high salinity lakes, and cryo-environments. Furthermore, the StRB and SrRB have Astrobiological significance as these anaerobic extremophiles may represent the dominant relic life forms that inhabited our planet during the extensive volcanic activity in the Earth's early evolutionary period.

  15. Inactivation of selected bacterial pathogens in dairy cattle manure by mesophilic anaerobic digestion (balloon type digester).

    PubMed

    Manyi-Loh, Christy E; Mamphweli, Sampson N; Meyer, Edson L; Okoh, Anthony I; Makaka, Golden; Simon, Michael

    2014-07-01

    Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%-99% reduced in the order: Campylobacter sp. (18 days) < Escherichia coli sp. (62 days) < Salmonella sp. (133 days) from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days. PMID:25026086

  16. Mesophilic versus thermophilic anaerobic digestion of cattle manure: methane productivity and microbial ecology.

    PubMed

    Moset, Veronica; Poulsen, Morten; Wahid, Radziah; Højberg, Ole; Møller, Henrik Bjarne

    2015-09-01

    In this study, productivity and physicochemical and microbiological (454 sequencing) parameters, as well as environmental criteria, were investigated in anaerobic reactors to contribute to the ongoing debate about the optimal temperature range for treating animal manure, and expand the general knowledge on the relation between microbiological and physicochemical process indicators. For this purpose, two reactor sizes were used (10?m(3) and 16?l), in which two temperature conditions (35°C and 50°C) were tested. In addition, the effect of the hydraulic retention time was evaluated (16 versus 20 days). Thermophilic anaerobic digestion showed higher organic matter degradation (especially fiber), higher pH and higher methane (CH?) yield, as well as better percentage of ultimate CH? yield retrieved and lower residual CH? emission, when compared with mesophilic conditions. In addition, lower microbial diversity was found in the thermophilic reactors, especially for Bacteria, where a clear intensification towards Clostridia class members was evident. Independent of temperature, some similarities were found in digestates when comparing with animal manure, including low volatile fatty acids concentrations and a high fraction of Euryarchaeota in the total microbial community, in which members of Methanosarcinales dominated for both temperature conditions; these indicators could be considered a sign of process stability. PMID:25737010

  17. The formation of illite from nontronite by mesophilic and thermophilic bacterial reaction

    USGS Publications Warehouse

    Jaisi, D.P.; Eberl, D.D.; Dong, H.; Kim, J.

    2011-01-01

    The formation of illite through the smectite-to-illite (S-I) reaction is considered to be one of the most important mineral reactions occurring during diagenesis. In biologically catalyzed systems, however, this transformation has been suggested to be rapid and to bypass the high temperature and long time requirements. To understand the factors that promote the S-I reaction, the present study focused on the effects of pH, temperature, solution chemistry, and aging on the S-I reaction in microbially mediated systems. Fe(III)-reduction experiments were performed in both growth and non-growth media with two types of bacteria: mesophilic (Shewanella putrefaciens CN32) and thermophilic (Thermus scotoductus SA-01). Reductive dissolution of NAu-2 was observed and the formation of illite in treatment with thermophilic SA-01 was indicated by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). A basic pH (8.4) and high temperature (65??C) were the most favorable conditions forthe formation of illite. A long incubation time was also found to enhance the formation of illite. K-nontronite (non-permanent fixation of K) was also detected and differentiated from the discrete illite in the XRD profiles. These results collectively suggested that the formation of illite associated with the biologically catalyzed smectite-to-illite reaction pathway may bypass the prolonged time and high temperature required for the S-I reaction in the absence of microbial activity.

  18. Inactivation of Selected Bacterial Pathogens in Dairy Cattle Manure by Mesophilic Anaerobic Digestion (Balloon Type Digester)

    PubMed Central

    Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Okoh, Anthony I.; Makaka, Golden; Simon, Michael

    2014-01-01

    Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%–99% reduced in the order: Campylobacter sp. (18 days) < Escherichia coli sp. (62 days) < Salmonella sp. (133 days) from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days. PMID:25026086

  19. Mesophilic versus thermophilic anaerobic digestion of cattle manure: methane productivity and microbial ecology

    PubMed Central

    Moset, Veronica; Poulsen, Morten; Wahid, Radziah; Højberg, Ole; Møller, Henrik Bjarne

    2015-01-01

    In this study, productivity and physicochemical and microbiological (454 sequencing) parameters, as well as environmental criteria, were investigated in anaerobic reactors to contribute to the ongoing debate about the optimal temperature range for treating animal manure, and expand the general knowledge on the relation between microbiological and physicochemical process indicators. For this purpose, two reactor sizes were used (10?m3 and 16?l), in which two temperature conditions (35°C and 50°C) were tested. In addition, the effect of the hydraulic retention time was evaluated (16 versus 20 days). Thermophilic anaerobic digestion showed higher organic matter degradation (especially fiber), higher pH and higher methane (CH4) yield, as well as better percentage of ultimate CH4 yield retrieved and lower residual CH4 emission, when compared with mesophilic conditions. In addition, lower microbial diversity was found in the thermophilic reactors, especially for Bacteria, where a clear intensification towards Clostridia class members was evident. Independent of temperature, some similarities were found in digestates when comparing with animal manure, including low volatile fatty acids concentrations and a high fraction of Euryarchaeota in the total microbial community, in which members of Methanosarcinales dominated for both temperature conditions; these indicators could be considered a sign of process stability. PMID:25737010

  20. Ecology of aerobic anoxygenic phototrophs in aquatic environments.

    PubMed

    Koblížek, Michal

    2015-11-01

    Recognition of the environmental role of photoheterotrophic bacteria has been one of the main themes of aquatic microbiology over the last 15 years. Aside from cyanobacteria and proteorhodopsin-containing bacteria, aerobic anoxygenic phototrophic (AAP) bacteria are the third most numerous group of phototrophic prokaryotes in the ocean. This functional group represents a diverse assembly of species which taxonomically belong to various subgroups of Alpha-, Beta- and Gammaproteobacteria. AAP bacteria are facultative photoheterotrophs which use bacteriochlorophyll-containing reaction centers to harvest light energy. The light-derived energy increases their bacterial growth efficiency, which provides a competitive advantage over heterotrophic species. Thanks to their enzymatic machinery AAP bacteria are active, rapidly growing organisms which contribute significantly to the recycling of organic matter. This chapter summarizes the current knowledge of the ecology of AAP bacteria in aquatic environments, implying their specific role in the microbial loop. PMID:26139241

  1. Biogas production from chicken manure at different organic loading rates in a mesophilic-thermopilic two stage anaerobic system.

    PubMed

    Dalk?l?c, Kenan; Ugurlu, Aysenur

    2015-09-01

    This study investigates the biogas production from chicken manure at different organic loading rates (OLRs), in a mesophilic-thermophilic two stage anaerobic system. The system was operated on semi continuous mode under different OLRs [1.9 g volatile solids (VS)/L·d - 4.7 g VS/L·d] and total solid (TS) contents (3.0-8.25%). It was observed that the anaerobic bacteria acclimatized to high total ammonia nitrogen concentration (>3000 mg/L) originated as a result of the degradation of chicken manure. High volatile fatty acid concentrations were tolerated by the system due to high pH in the reactors. The maximum average biogas production rate was found as 554 mL/g VSfeed while feeding 2.2 g VS/L-d (2.3% VS - 3.8% TS) to the system. Average methane content of produced biogas was 74% during the study. PMID:26111600

  2. Bacterial community structure in treated sewage sludge with mesophilic and thermophilic anaerobic digestion.

    PubMed

    Stiborova, Hana; Wolfram, Jan; Demnerova, Katerina; Macek, Tomas; Uhlik, Ondrej

    2015-11-01

    Stabilized sewage sludge is applied to agricultural fields and farmland due to its high organic matter content. The aim of this study was to investigate the effects of two types of sludge stabilization, mesophilic anaerobic digestion (MAD) and thermophilic anaerobic digestion (TAD), on bacterial communities in sludge, including the presence of pathogenic microorganisms. Bacterial community structure and phylogenetic diversity were analyzed in four sewage sludge samples from the Czech Republic. Analysis of 16S ribosomal RNA (rRNA) genes showed that investigated sludge samples harbor diverse bacterial populations with only a few taxa present across all samples. Bacterial diversity was higher in sludge samples after MAD versus TAD treatment, and communities in MAD-treated sludge shared the highest genetic similarities. In all samples, the bacterial community was dominated by reads affiliated with Proteobacteria. The sludge after TAD treatment had considerably higher number of reads of thermotolerant/thermophilic taxa, such as the phyla Deinococcus-Thermus and Thermotogae or the genus Coprothermobacter. Only one operational taxonomic unit (OTU), which clustered with Rhodanobacter, was detected in all communities at a relative abundance >1 %. All of the communities were screened for the presence of 16S rRNA gene sequences of pathogenic bacteria using a database of 122 pathogenic species and ?98 % identity threshold. The abundance of such sequences ranged between 0.23 and 1.57 % of the total community, with lower numbers present after the TAD treatment, indicating its higher hygienization efficiency. Sequences clustering with nontuberculous mycobacteria were present in all samples. Other detected sequences of pathogenic bacteria included Streptomyces somaliensis, Acinetobacter calcoaceticus, Alcaligenes faecalis, Gordonia spp., Legionella anisa, Bordetella bronchiseptica, Enterobacter aerogenes, Brucella melitensis, and Staphylococcus aureus. PMID:25921720

  3. Experimental Evolution of a Facultative Thermophile from a Mesophilic Ancestor

    PubMed Central

    Blaby, Ian K.; Lyons, Benjamin J.; Wroclawska-Hughes, Ewa; Phillips, Grier C. F.; Pyle, Tyler P.; Chamberlin, Stephen G.; Benner, Steven A.; Lyons, Thomas J.

    2012-01-01

    Experimental evolution via continuous culture is a powerful approach to the alteration of complex phenotypes, such as optimal/maximal growth temperatures. The benefit of this approach is that phenotypic selection is tied to growth rate, allowing the production of optimized strains. Herein, we demonstrate the use of a recently described long-term culture apparatus called the Evolugator for the generation of a thermophilic descendant from a mesophilic ancestor (Escherichia coli MG1655). In addition, we used whole-genome sequencing of sequentially isolated strains throughout the thermal adaptation process to characterize the evolutionary history of the resultant genotype, identifying 31 genetic alterations that may contribute to thermotolerance, although some of these mutations may be adaptive for off-target environmental parameters, such as rich medium. We undertook preliminary phenotypic analysis of mutations identified in the glpF and fabA genes. Deletion of glpF in a mesophilic wild-type background conferred significantly improved growth rates in the 43-to-48°C temperature range and altered optimal growth temperature from 37°C to 43°C. In addition, transforming our evolved thermotolerant strain (EVG1064) with a wild-type allele of glpF reduced fitness at high temperatures. On the other hand, the mutation in fabA predictably increased the degree of saturation in membrane lipids, which is a known adaptation to elevated temperature. However, transforming EVG1064 with a wild-type fabA allele had only modest effects on fitness at intermediate temperatures. The Evolugator is fully automated and demonstrates the potential to accelerate the selection for complex traits by experimental evolution and significantly decrease development time for new industrial strains. PMID:22020511

  4. Glucose-sensing proteins from mesophilic and thermophilic bacteria as new tools in diabetes monitoring

    NASA Astrophysics Data System (ADS)

    D'Auria, S.; Rossi, Mose; Lakowicz, Joseph R.

    2001-05-01

    We developed a new method of glucose sensing using inactive forms of glucose oxidase from Aspergillus niger and glucose dehydrogenase from the thermophilic microorganism Thermoplasma acidophilum. Glucose oxidase was rendered inactive by removal of the FAD cofactor. The resulting apo- glucose oxidase still binds glucose as observed from a decrease in its intrinsic tryptophan fluorescence. 8- Anilino-1-naphthalene sulfonic acid (ANS) was found to bind spontaneously to apo-glucose oxidase as seen from an enhancement of the ANS fluorescence. The steady state intensity of the bound ANS decreased 25% upon binding of glucose, and the mean lifetime of the bound ANS decreased about 40%. These spectral changes occurred with a midpoint from 10 to 20 mM glucose, which is comparable to the Ko of holo-glucose oxidase. These results suggest that apo- glucose oxidase can be used as a reversible non-consuming sensor for glucose.

  5. A novel biological sulfate reduction method using hydrogenogenic carboxydotrophic mesophilic bacteria.

    PubMed

    Sinharoy, Arindam; Manikandan, N Arul; Pakshirajan, Kannan

    2015-09-01

    Sulfate reduction by carbon monoxide (CO) utilizing anaerobic biomass from a large scale upflow anaerobic sludge blanket reactor was studied. Anaerobic mixed microbial consortia from five different sources were initially examined for their biological CO conversion potential. Among the different biomass, the biomass from an upflow anaerobic sludge blanket reactor treating domestic wastewater, located in Kavoor, Karnataka, India, showed a maximum CO conversion efficiency. The effect of three main culture parameters, i.e. inoculum volume, initial CO concentration and temperature on simultaneous CO conversion and sulfate reduction was assessed employing the Taguchi experimental design technique. A maximum CO conversion of 85.62% and a maximum sulfate reduction of 50.65% were achieved. Furthermore, the experimental data was fitted to substrate inhibition models reported in the literature. Among the different models, Monods and Haldane kinetic models were found most suitable to describe the kinetics of biomass growth and CO removal by the anaerobic biomass. PMID:26081625

  6. Bacteria recovered from endometritis and pyometra in the beef cow 

    E-print Network

    Mikulec, Rashel Thi

    1999-01-01

    One hundred and one uteri from beef cows with pyometra were collected from a slaughterhouse. Samples of uterine exudate were cultured for aerobic, microaerophilic, and anaerobic bacteria, and also tested for Trichomonas spp. A section of uterine...

  7. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P (Aiken, SC); Bessette, Bernard J (Aiken, SC); March, John C (Winterville, GA); McComb, Scott T. (Andersonville, SC)

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  8. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P (Aiken, SC); Bessette, Bernard J (Aiken, SC); March, John (Winterville, GA); McComb, Scott T. (Andersonville, SC)

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  9. An ancient divergence among the bacteria. [methanogenic phylogeny

    NASA Technical Reports Server (NTRS)

    Balch, W. E.; Magrum, L. J.; Fox, G. E.; Wolfe, R. S.; Woese, C. R.

    1977-01-01

    The 16S ribosomal RNZs from two species of met methanogenic bacteria, the mesophile Methanobacterium ruminantium and the thermophile Methanobacterium thermoautotrophicum, have been characterized in terms of the oligonucleotides produced by digestion with T1 ribonuclease. These two organisms are found to be sufficiently related that they can be considered members of the same genus or family. However, they bear only slight resemblance to 'typical' Procaryotic genera; such as Escherichia, Bacillus and Anacystis. The divergence of the methanogenic bacteria from other bacteria may be the most ancient phylogenetic event yet detected - antedating considerably the divergence of the blue green algal line for example, from the main bacterial line.

  10. Performance of mesophilic anaerobic granules for removal of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) from aqueous solution.

    PubMed

    An, Chun-jiang; He, Yan-ling; Huang, Guo-he; Liu, Yong-hong

    2010-07-15

    The performance of mesophilic anaerobic granules to degrade octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) was investigated under various conditions. The results of batch experiments showed that anaerobic granules were capable of removing HMX from aqueous solution with high efficiency. Both biotic and abiotic mechanisms contributed to the removal of HMX by anaerobic granules under mesophilic conditions. Adsorption appeared to play a significant role in the abiotic process. Furthermore, HMX could be biodegraded by anaerobic granules as the sole substrate. After 16 days of incubation, 99.04% and 96.42% of total HMX could be removed by 1g VSS/L acclimated and unacclimated granules, respectively. Vancomycin, an inhibitor of acetogenic bacteria, caused a significant inhibition of HMX biotransformation, while 2-bromoethanesulfonic acid, an inhibitor of methanogenic bacteria, only resulted in a slight decrease of metabolic activity. The presence of the glucose, as a suitable electron donor and carbon source, was found to enhance the degradation of HMX by anaerobic granules. Our study showed that sulfate had little adverse effects on biotransformation of HMX by anaerobic granules. However, nitrate had significant inhibitory effect on the extent of HMX removal especially in the initial period. This study offered good prospects of using high-rate anaerobic technology in the treatment of munition wastewater. PMID:20359815

  11. Metagenome approaches revealed a biological prospect for improvement on mesophilic cellulose degradation.

    PubMed

    Wang, Yubo; Xia, Yu; Ju, Feng; Zhang, Tong

    2015-12-01

    Improvement on the bioconversion of cellulosic biomass depends much on the expanded knowledge on the underlying microbial structure and the relevant genetic information. In this study, metagenomic analysis was applied to characterize an enriched mesophilic cellulose-converting consortium, to explore its cellulose-hydrolyzing genes, and to discern genes involved in methanogenesis. Cellulose conversion efficiency of the mesophilic consortium enriched in this study was around 70 %. Apart from methane, acetate was the major fermentation product in the liquid phase, while propionate and butyrate were also detected at relatively high concentrations. With the intention to uncover the biological factors that might shape the varying cellulose conversion efficiency at different temperatures, results of this mesophilic consortium were then compared with that of a previously reported thermophilic cellulose-converting consortium. It was found that the mesophilic consortium harbored a larger pool of putative carbohydrate-active genes, with 813 of them in 54 GH modules and 607 genes in 13 CBM modules. Methanobacteriaceae and Methanosaetaceae were the two methanogen families identified, with a preponderance of the hydrogenotrophic Methanobacteriaceae. In contrast to its relatively high diversity and high abundance of carbohydrate-active genes, the abundance of genes involved in the methane metabolism was comparatively lower in the mesophilic consortium. A biological enhancement on the methanogenic process might serve as an effective option for the improvement of the cellulose bioconversion at mesophilic temperature. PMID:26359182

  12. AEROBIC BIOTRANSFORMATION OF TOXIC ORGANICS IN WASTEWATER

    E-print Network

    #12;AEROBIC BIOTRANSFORMATION OF TOXIC ORGANICS IN WASTEWATER DOE FRAP 1997-15 Prepared for under three environments - anaerobic, anoxic- denitrifying and aerobic: Environment Variables Levels Studied Aerobic Dissolved Oxygen Conc. Cosubstrate Conc. 2 3 Anaerobic Anoxic Denitrifying Cosubstrate

  13. Comparative metagenomic analysis of bacterial populations in three full-scale mesophilic anaerobic manure digesters.

    PubMed

    St-Pierre, Benoit; Wright, André-Denis G

    2014-03-01

    While the use of anaerobic digestion to generate methane as a source of bioenergy is increasing worldwide, our knowledge of the microbial communities that perform biomethanation is very limited. Using next-generation sequencing, bacterial population profiles were determined in three full-scale mesophilic anaerobic digesters operated on dairy farms in the state of Vermont (USA). To our knowledge, this is the first report of a metagenomic analysis on the bacterial population of anaerobic digesters using dairy manure as their main substrate. A total of 20,366 non-chimeric sequence reads, covering the V1-V2 hypervariable regions of the bacterial 16S rRNA gene, were assigned to 2,176 operational taxonomic units (OTUs) at a genetic distance cutoff value of 5 %. Based on their limited sequence identity to validly characterized species, the majority of OTUs identified in our study likely represented novel bacterial species. Using a naïve Bayesian classifier, 1,624 anaerobic digester OTUs could be assigned to 16 bacterial phyla, while 552 OTUs could not be classified and may belong to novel bacterial taxonomic groups that have yet to be described. Firmicutes, Bacteroidetes, and Chloroflexi were the most highly represented bacteria overall, with Bacteroidetes and Chloroflexi showing the least and the most variation in abundance between digesters, respectively. All digesters shared 132 OTUs, which as a "core" group represented 65.4 to 70.6 % of sequences in individual digesters. Our results show that bacterial populations from microbial communities of anaerobic manure digesters can display high levels of diversity despite sharing a common core substrate. PMID:24085391

  14. Biogas production and methanogenic archaeal community in mesophilic and thermophilic anaerobic co-digestion processes.

    PubMed

    Yu, D; Kurola, J M; Lähde, K; Kymäläinen, M; Sinkkonen, A; Romantschuk, M

    2014-10-01

    Over 258 Mt of solid waste are generated annually in Europe, a large fraction of which is biowaste. Sewage sludge is another major waste fraction. In this study, biowaste and sewage sludge were co-digested in an anaerobic digestion reactor (30% and 70% of total wet weight, respectively). The purpose was to investigate the biogas production and methanogenic archaeal community composition in the anaerobic digestion reactor under meso- (35-37 °C) and thermophilic (55-57 °C) processes and an increasing organic loading rate (OLR, 1-10 kg VS m(-3) d(-1)), and also to find a feasible compromise between waste treatment capacity and biogas production without causing process instability. In summary, more biogas was produced with all OLRs by the thermophilic process. Both processes showed a limited diversity of the methanogenic archaeal community which was dominated by Methanobacteriales and Methanosarcinales (e.g. Methanosarcina) in both meso- and thermophilic processes. Methanothermobacter was detected as an additional dominant genus in the thermophilic process. In addition to operating temperatures, the OLRs, the acetate concentration, and the presence of key substrates like propionate also affected the methanogenic archaeal community composition. A bacterial cell count 6.25 times higher than archaeal cell count was observed throughout the thermophilic process, while the cell count ratio varied between 0.2 and 8.5 in the mesophilic process. This suggests that the thermophilic process is more stable, but also that the relative abundance between bacteria and archaea can vary without seriously affecting biogas production. PMID:24837280

  15. Exercise, Animal Aerobics, and Interpretation?

    ERIC Educational Resources Information Center

    Oliver, Valerie

    1996-01-01

    Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

  16. Effect of sulfate addition on methane production and sulfate reduction in a mesophilic acetate-fed anaerobic reactor.

    PubMed

    Yang, Sen-Lin; Tang, Yue-Qin; Gou, Min; Jiang, Xia

    2015-04-01

    A mesophilic anaerobic moving bed biofilm reactor (MBBR) was operated to evaluate the effect of sulfate addition on methane production and sulfate reduction using acetate as the sole carbon source. The results show that at the organic loading rate of 4.0 g TOC/L/day, the TOC removal efficiencies and the biogas production rates achieved over 95 % and 7000 mL/L/day without sulfate, respectively, and slightly decreased with sulfate addition (500-800 mg/L). Methane production capacities were not influenced significantly with the addition of sulfate, while sulfate reduction efficiencies were not stable with 23-87 % in the acetate-fed reactor. Fluorescent in situ hybridization (FISH) was used to analyze the functional microbial compositions of acetate-degrading methane-producing bacteria (MPB) and sulfate-reducing bacteria (SRB) in the reactor. The results found that as the increase of sulfate concentration, the proportion of Methanomicrobiales increased up to 58?±?2 %, while Methanosaeta and Methanosarcina decreased. The dominant methanogens shifted into hydrogenotrophic methanogens from even distribution of acetoclastic and hydrogenotrophic methanogens. When hydrogenotrophic methanogens were dominant, sulfate reduction efficiency was high, while sulfate reduction efficiency was low as acetoclastic methanogens were dominant. PMID:25427678

  17. Clinical microbiology of coryneform bacteria.

    PubMed Central

    Funke, G; von Graevenitz, A; Clarridge, J E; Bernard, K A

    1997-01-01

    Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed. PMID:8993861

  18. Different management practices are associated with mesophilic and thermophilic spore levels in bulk tank raw milk.

    PubMed

    Miller, R A; Kent, D J; Boor, K J; Martin, N H; Wiedmann, M

    2015-07-01

    Bacterial endospores (also referred to as spores) present in raw milk are capable of surviving pasteurization and other adverse conditions encountered during dairy powder production. Therefore, requiring low spore levels in raw ingredients (e.g., raw milk) may be necessary for producing dairy powders with low spore counts. To identify potential associations between management practices and spore levels in raw milk, we sampled bulk tank raw milk from 33 farms throughout New York State every other month for 1yr. Following spore pasteurization (80°C for 12min), samples were incubated at 3 different temperatures to enumerate psychrotolerant (6°C for 10 d), mesophilic (32°C for 48h), and thermophilic (55°C for 48h) spores. An additional enrichment procedure was used to detect spores present at low levels (<10 spores/mL). Overall, psychrotolerant, mesophilic, and thermophilic spores were detected (at levels ?10 spores/mL) in 1, 74, and 58% of bulk tank raw milk samples, respectively. Although thermophilic spore levels could not be quantified (due to bacterial swarming), mesophilic spore levels ranged from below detection (<10 spores/mL) to 680 spores/mL. Data collected through surveys were used to identify management practices associated with either mesophilic or thermophilic spore levels. We found that different management practices are associated with mesophilic and thermophilic spore levels. Low mesophilic spore levels in bulk tank raw milk samples were associated with (1) large herd size, (2) use of sawdust or sand bedding, and (3) not fore stripping during the premilking routine. Management practices that were associated with lower odds of having a thermophilic spore level ?10 spores/mL are (1) large herd size, (2) spray-based application of the postmilking disinfectant, (3) dry massaging the udder during the premilking routine, and (4) the use of straw bedding. Collectively, these results suggest that different management practices may influence mesophilic and thermophilic spore levels in raw milk. PMID:25958277

  19. Study examines sulfate-reducing bacteria activity

    SciTech Connect

    McElhiney, J.E.; Hardy, J.A.; Rizk, T.Y.; Stott, J.F.D.; Eden, R.D.

    1996-12-09

    Low-sulfate seawater injection can reduce the potential of an oil reservoir turning sour because of sulfate-reducing bacteria. Sulfate-reducing bacteria (SRB) convert sulfate ions in seawater used in waterflooding into sulfide with the concomitant oxidation of a carbon source. A recent study at Capcis investigated the efficiency of SRB under various conditions of sulfate limitation. This study was conducted in a flowing bioreactor at 2,000 psia with different temperature zones (mesophilic 35 C and thermophilic 60--80 C). The study mixed microfloral populations derived from real North Sea-produced fluids, and included an active population of marine methanogenic bacteria present to provide competition for the available carbon sources. In general, results showed that SRB continue to convert sulfate to sulfide in stoichiometric quantities without regard to absolute concentrations. The paper discusses the results and recommends nanofiltration of seawater for ``sweet`` reservoirs.

  20. Quantifying factors limiting aerobic degradation during aerobic bioreactor landfilling.

    PubMed

    Yazdani, Ramin; Mostafid, M Erfan; Han, Byunghyun; Imhoff, Paul T; Chiu, Pei; Augenstein, Don; Kayhanian, Masoud; Tchobanoglous, George

    2010-08-15

    A bioreactor landfill cell at Yolo County, California was operated aerobically for six months to quantify the extent of aerobic degradation and mechanisms limiting aerobic activity during air injection and liquid addition. The portion of the solid waste degraded anaerobically was estimated and tracked through time. From an analysis of in situ aerobic respiration and gas tracer data, it was found that a large fraction of the gas-filled pore space was in immobile zones where it was difficult to maintain aerobic conditions, even at relatively moderate landfill cell-average moisture contents of 33-36%. Even with the intentional injection of air, anaerobic activity was never less than 13%, and sometimes exceeded 65%. Analyses of gas tracer and respiration data were used to quantify rates of respiration and rates of mass transfer to immobile gas zones. The similarity of these rates indicated that waste degradation was influenced significantly by rates of oxygen transfer to immobile gas zones, which comprised 32-92% of the gas-filled pore space. Gas tracer tests might be useful for estimating the size of the mobile/immobile gas zones, rates of mass transfer between these regions, and the difficulty of degrading waste aerobically in particular waste bodies. PMID:20704218

  1. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Technical Reports Server (NTRS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-01-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  2. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Astrophysics Data System (ADS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-03-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  3. Treatment of phenolics, aromatic hydrocarbons, and cyanide-bearing wastewater in individual and combined anaerobic, aerobic, and anoxic bioreactors.

    PubMed

    Sharma, Naresh K; Philip, Ligy

    2015-01-01

    Studies were conducted on a mixture of pollutants commonly found in coke oven wastewater (CWW) to evaluate the biodegradation of various pollutants under anaerobic, aerobic, and anoxic conditions. The removal of the pollutants was monitored during individual bioreactor operation and using a combination of bioreactors operating in anaerobic-aerobic-anoxic sequence. While studying the performance of individual reactors, it was observed that cyanide removal (83.3 %) was predominant in the aerobic bioreactor, while much of the chemical oxygen demand (COD) (69 %) was consumed in the anoxic bioreactor. With the addition of cyanide, the COD removal efficiency was affected in all the bioreactors, and several intermediates were detected. While treating synthetic CWW using the combined bioreactor system, the overall COD removal efficiency was 86.79 % at an OLR of 2.4 g COD/L/day and an HRT of 96 h. The removal efficiency of 3,5-xylenol and cyanide, with inlet concentration of 150 and 10 mg/L, was found to be 91.8 and 93.6 % respectively. It was found that the impact of xylenol on the performance of the bioreactors was less than cyanide toxicity. Molecular analysis using T-RFLP revealed the dominance of strictly aerobic, mesophilic proteobacterium, Bosea minatitlanensis, in the aerobic bioreactor. The anoxic bioreactor was dominant with Rhodococcus pyridinivorans, known for its remarkable aromatic decomposing activity, while an unclassified Myxococcales bacterium was identified as the predominant bacterial species in the anaerobic bioreactor. PMID:25267355

  4. Petrifilm plates for enumeration of bacteria counts in goat milk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    PetrifilmTM Aerobic Count (AC) and Coliform Count (CC) plates were validated against standard methods for enumeration of coliforms, total bacteria, and psychrotrophic bacteria in raw (n = 39) and pasteurized goat milk (n = 17) samples. All microbiological data were transformed into log form and sta...

  5. Enhancement of microbial quality and inactivation of pathogenic bacteria by gamma irradiation of ready-to-cook Iranian barbecued chicken

    NASA Astrophysics Data System (ADS)

    Fallah, Aziz A.; Siavash Saei-Dehkordi, S.; Rahnama, Mohammad

    2010-10-01

    Ready-to-cook Iranian barbecued chicken consists of cubed chicken breast, lemon juice, salt, red pepper, onion, saffron and vegetable oil with an overall pH value of about 5.5. This product is sometimes consumed under-cooked, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. In this study, the effect of gamma irradiation (0, 1.5, 3 and 4.5 kGy) on the microbial quality of ready-to-cook (RTC) barbecued chicken samples stored at 4 °C for 15 days was investigated. Moreover, the effectiveness of irradiation for inactivating Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella typhimurium inoculated into the samples was also studied. Irradiation of the samples resulted in dose dependent reduction in counts of aerobic mesophilic bacteria, yeasts and molds, Enterobacteriaceae and lactic acid bacteria. Among the microbial flora, yeasts and molds and Enterobacteriaceae were more sensitive to irradiation and got completely eliminated at dose of 3 kGy. D10 values of L. monocytogenes, E. coli O157:H7 and S. typhimurium inoculated into the samples were 0.680, 0.397 and 0.601 kGy, respectively. An irradiation dose of 3 kGy reduced the counts of E. coli O157:H7 to an undetectable level in RTC barbecued chicken but was ineffective on elimination of L. monocytogenes and S. typhimurium. However, none of the food-borne pathogens were detected in the samples irradiated at 4.5 kGy. This study showed that irradiation had no undesirable effects on the initial sensory attributes of barbecued chicken. At the end of the storage period, irradiated samples were more acceptable compared to non-irradiated ones.

  6. Comparison of mesophilic and thermophilic anaerobic digestion of sugar beet pulp: performance, dewaterability and foam control.

    PubMed

    Suhartini, Sri; Heaven, Sonia; Banks, Charles J

    2014-01-01

    Digestion of sugar beet pulp was assessed in relation to biogas and methane production, foaming potential, and digestate dewaterability. Four 4-litre working volume digesters were operated mesophilically (37±0.5 °C) and four thermophilically (55±0.5 °C) over three hydraulic retention times. Digesters were operated in duplicate at organic loading rates (OLR) of 4 and 5 g volatile solids l(-1) day(-1) without water addition. Thermophilic digestion gave higher biogas and methane productivity than mesophilic and was able to operate at the higher OLR, where mesophilic digestion showed signs of instability. Digestate dewaterability was assessed using capillary suction time and frozen image centrifugation. The occurrence of, or potential for, stable foam formation was assessed using a foaming potential test. Thermophilic operation allowed higher loadings to be applied without loss of performance, and gave a digestate with superior dewatering characteristics and very little foaming potential. PMID:24291796

  7. Project summary report, DE-FG02-96ER14668 [Dissolution of Fe(III)(hydr)oxides by aerobic microorganisms

    SciTech Connect

    Maurice, Patricia A.

    2001-02-15

    The purpose of this research was to determine the rates and mechanisms whereby aerobic bacteria dissolve Fe(III)(hydr)oxides and clays in aerobic environments where Fe is insoluble. We determined that an aerobic P. mendocina bacterium dissolves the clay mineral kaolinite in order to obtain nutrient Fe. We also determined that the rate of dissolution of the Fe hydroxide mineral goethite increases with Al substitution. Both of these observations have important implications for Fe cycling and for mineral dissolution studies.

  8. Aerobic and anaerobic bacteriology of purulent nasopharyngitis in children.

    PubMed Central

    Brook, I

    1988-01-01

    Cultures of aerobic and anaerobic bacteria were obtained from the inferior nasal meatus of 25 children with purulent nasopharyngitis and from 25 controls. Microorganisms were isolated from all specimens. A total of 98 isolates (3.9 per patient), 45 aerobes (1.8 per patient) and 53 anaerobes (2.1 per patient), were isolated in patients with purulent nasopharyngitis. Seventy-three isolates (2.9 per patient), 47 aerobes (1.9 per patient) and 26 anaerobes (1.0 per patient) were found in the controls. The organisms recovered in statistically significantly higher numbers in patients with nasopharyngitis were Streptococcus pneumoniae, Haemophilus sp., Peptostreptococcus spp., Fusobacterium spp., and Bacteroides spp. The organisms recovered in significantly higher numbers in controls were Staphylococcus aureus and Propionibacterium acnes. beta-Lactamase activity was detected in 19 isolates recovered from 15 individuals (9 patients and 6 controls). These findings demonstrate the aerobic-anaerobic polymicrobial flora associated with purulent nasopharyngitis. Further studies are indicated to evaluate the pathogenic role of these organisms in this condition. PMID:3356794

  9. Dynamics Associated with Prolonged Ensiling and Aerobic Deterioration of Total Mixed Ration Silage Containing Whole Crop Corn.

    PubMed

    Wang, Huili; Ning, Tingting; Hao, Wei; Zheng, Mingli; Xu, Chuncheng

    2016-01-01

    This study investigated the dynamics associated with prolonged ensiling and aerobic deterioration of whole crop corn (WCC) silages and total mixed ration (TMR) silages containing WCC (C-TMR silages) to clarify the differences that account for the enhanced aerobic stability of TMR silages. Laboratory-scale barrel silos were randomly opened after 7, 14, 28, and 56 d of ensiling and were subjected to analyses of fermentation quality, microbial and temperature dynamics during aerobic exposure. WCC and C-TMR silages were both well preserved and microorganisms were inhibited with prolonged ensiling, including lactic acid bacteria. Yeast were inhibited to below the detection limit of 500 cfu/g fresh matter within 28 d of ensiling. Aerobic stability of both silages was enhanced with prolonged ensiling, whereas C-TMR silages were more aerobically stable than WCC silages for the same ensiling period. Besides the high moisture content, the weak aerobic stability of WCC silage is likely attributable to the higher lactic acid content and yeast count, which result from the high water-soluble carbohydrates content in WCC. After silo opening, yeast were the first to propagate and the increase in yeast levels is greater than that of other microorganisms in silages before deterioration. Besides, increased levels of aerobic bacteria were also detected before heating of WCC silages. The temperature dynamics also indicated that yeast are closely associated with the onset of the aerobic deterioration of C-TMR silage, whereas for WCC silages, besides yeast, aerobic bacteria also function in the aerobic deterioration. Therefore, the inclusion of WCC might contribute to the survival of yeast during ensiling but not influence the role of yeast in deterioration of C-TMR silages. PMID:26732329

  10. Anaerobic submerged membrane bioreactor (AnSMBR) for municipal wastewater treatment under mesophilic and psychrophilic temperature conditions.

    PubMed

    Martinez-Sosa, David; Helmreich, Brigitte; Netter, Thomas; Paris, Stefania; Bischof, Franz; Horn, Harald

    2011-11-01

    A pilot scale anaerobic submerged membrane bioreactor (AnSMBR) with an external filtration unit for municipal wastewater treatment was operated for 100 days. Besides gas sparging, additional shear was created by circulating sludge to control membrane fouling. During the first 69 days, the reactor was operated under mesophilic temperature conditions. Afterwards, the temperature was gradually reduced to 20 °C. A slow and linear increase in the filtration resistance was observed under critical flux conditions (7 L/(m2 h)) at 35 °C. However, an increase in the fouling rate probably linked to an accumulation of solids, a higher viscosity and soluble COD concentrations in the reactor was observed at 20 °C. The COD removal efficiency was close to 90% under both temperature ranges. Effluent COD and BOD5 concentrations were lower than 80 and 25 mg/L, respectively. Pathogen indicator microorganisms (fecal coliforms bacteria) were reduced by log(10)5. Hence, the effluent could be used for irrigation purposes in agriculture. PMID:21962536

  11. Correlation between antibiotic and biocide resistance in mesophilic and psychrotrophic Pseudomonas spp. isolated from slaughterhouse surfaces throughout meat chain production.

    PubMed

    Lavilla Lerma, Leyre; Benomar, Nabil; Casado Muñoz, María del Carmen; Gálvez, Antonio; Abriouel, Hikmate

    2015-10-01

    The aim of this study was to evaluate biocide susceptibility in mesophilic and psychrotrophic pseudomonads isolated from surfaces of a goat and lamb slaughterhouse, which was representative of the region. To determine biocide resistance in pseudomonads, we determined for the first time the epidemiological cut-off values (ECOFFs) of benzalkonium, cetrimide, chlorhexidine, hexachlorophene, P3 oxonia, polyhexamethylene guanidine hydrochloride (PHMG), topax 66 and triclosan being generally very similar in different Pseudomonas spp. with some exceptions. Thus, resistance of pseudomonads was mainly shown to triclosan, and in lesser extent to cetrimide and benzalkonium chloride depending on the species, however they were highly susceptible to industrial formulations of biocides. By means of statistical analysis, positive correlations between antibiotics, biocides and both antimicrobials in pseudomonads were detected suggesting a co- or cross resistance between different antimicrobials in goat and lamb slaughterhouse environment. Cross-resistance between biocides and antibiotics in pseudomonads were especially detected between PHMG or triclosan and different antibiotics depending on the biocide and the population type. Thus, the use of those biocides as disinfectant in slaughterhouse zones must be carefully evaluated because of the selection pressure effect of antimicrobials on the emergence of resistant bacteria which could be spread to the consumer. It is noteworthy that specific industrial formulations such as topax 66 and oxonia P3 showed few correlations with antibiotics (none or 1-2 antibiotics) which should be taken into consideration for disinfection practices in goat and lamb slaughterhouse. PMID:26187825

  12. Growth of aerobic bacteria on alkali-solubilized lignite

    SciTech Connect

    Polman, J.K.; Breckenridge, C.R.; Dugan, P.R.; Quigley, D.R.

    1991-12-31

    Coal contains a complex mixture of organic compounds, the variety of which depends on the particular type of coal. There is a general agreement that coal is composed of a macromolecular fraction and a lower-mol-wt fraction that are noncovalently associated with each other. Huttinger and Michenfelder have proposed a structural unit for the macromolecular portion of a lignite coal that comprises 2 and 3-ring fused aromatics, paraffin, terpene, cycloaliphatics, hydrocarbon bridges, several carboxyl moieties, straight-chain saturated hydrocarbons, branched-chain hydrocarbons, sulfur heterocyclics, ether linkages, alcohol groups, nitrogen heterocyclics, and chelated metals. Low-mol-wt compounds found in coal can be separated from macromolecules by extraction with organic solvents, such as tetrahydrofuran. Low-mol-wt organic compounds that have been revealed by such extractions include straight-chain (C{sub 13}-C{sub 33}), branched, and cyclic alkanes; aryl and aryl alkyl compounds with 1-6 rings; and phenolic compounds. In low-ranked coals, branched alkanes predominate over straight chain. This report describes the enrichment for, and isolation of, microorganisms that are capable of modifying lignite.

  13. Aerobic versus anaerobic wastewater treatment

    SciTech Connect

    Robinson, D.G.; White, J.E.; Callier, A.J.

    1997-04-01

    Biological wastewater treatment facilities are designed to emulate the purification process that occurs naturally in rivers, lakes and streams. In the simulated environment, conditions are carefully manipulated to spur the degradation of organic contaminants and stabilize the residual sludge. Whether the treatment process is aerobic or anaerobic is determined by a number of factors, including the composition of the wastewater, the degree of stabilization required for environmental compliance and economic viability. Because anaerobic digestion is accomplished without oxygen in a closed system, it is economical for pretreatment of high-strength organic sludge. Before the effluent can be discharged, however, followup treatment using an aerobic process is required. Though it has the drawback of being energy intensive, aerobic processing, the aeration of organic sludges in an open tank, is the primary method for treatment of industrial and municipal wastewater. Aerobic processes are more stable than anaerobic approaches and can be done rather simply, particularly with trickling filters. Gradually, the commercialization of modular systems that are capable of aerobic and anaerobic digestion will blur the distinctions between the two processes. Systems that boast those capabilities are available now.

  14. Bacterial survival and association with sludge flocs during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions.

    PubMed Central

    Farrah, S R; Bitton, G

    1983-01-01

    The fate of indicator bacteria, a bacterial pathogen, and total aerobic bacteria during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions was determined. Correlation coefficients were calculated between physical and chemical parameters (temperature, dissolved oxygen, pH, total solids, and volatile solids) and either the daily change in bacterial numbers or the percentage of bacteria in the supernatant. The major factor influencing survival of Salmonella typhimurium and indicator bacteria during aerobic digestion was the temperature of sludge digestion. At 28 degrees C with greater than 4 mg of dissolved oxygen per liter, the daily change in numbers of these bacteria was approximately -1.0 log10/ml. At 6 degrees C, the daily change was less than -0.3 log10/ml. Most of the bacteria were associated with the sludge flocs during aerobic digestion of sludge at 28 degrees C with greater than 2.4 mg of dissolved oxygen per liter. Lowering the temperature or the amount of dissolved oxygen decreased the fraction of bacteria associated with the flocs and increased the fraction found in the supernatant. PMID:6401978

  15. Improving aerobic stability and biogas production of maize silage using silage additives.

    PubMed

    Herrmann, Christiane; Idler, Christine; Heiermann, Monika

    2015-12-01

    The effects of air stress during storage, exposure to air at feed-out, and treatment with silage additives to enhance aerobic stability on methane production from maize silage were investigated at laboratory scale. Up to 17% of the methane potential of maize without additive was lost during seven days exposure to air on feed-out. Air stress during storage reduced aerobic stability and further increased methane losses. A chemical additive containing salts of benzoate and propionate, and inoculants containing heterofermentative lactic acid bacteria were effective to increase aerobic stability and resulted in up to 29% higher methane yields after exposure to air. Exclusion of air to the best possible extent and high aerobic stabilities should be primary objectives when ensiling biogas feedstocks. PMID:26348286

  16. COMPARATIVE EVALUATION OF MESOPHILIC AND THERMOPHILIC DIGESTION - PHASE I. TEMPERATURE TRANSITION STUDIES

    EPA Science Inventory

    As part of a larger study on the comparison between mesophilic and thermophilic anaerobic digestion, a study of the operation of anaerobic systems under temperature transition was conducted. Systems seeded with domestic sewage sludge, but subsequently fed a chemically defined com...

  17. COMPARATIVE EVALUATION OF MESOPHILIC AND THERMOPHILIC ANAEROBIC DIGESTION. PHASE 2. STEADY STATE STUDIES

    EPA Science Inventory

    A study was conducted of the relative performance of anaerobic digestion systems under mesophilic and thermophilic conditions. Fifty liter laboratory scale digesters were fed primary sludge from the Allentown, PA Waste Water Treatment Plant. Long-term, steady-state performance da...

  18. COMPARATIVE EVALUATION OF MESOPHILIC AND THERMOPHILIC DIGESTION - PHASE II. STEADY STATE STUDIES

    EPA Science Inventory

    A study of the relative performance of anaerobic digestion systems under mesophilic and thermophilic conditions was conducted. Fifty liter laboratory scale digesters were fed primary sludge from the Allentown, PA Waste Water Treatment Plant. Long-term, steady-state performance da...

  19. Kinetic characterization of thermophilic and mesophilic anaerobic digestion for coffee grounds and waste activated sludge.

    PubMed

    Li, Qian; Qiao, Wei; Wang, Xiaochang; Takayanagi, Kazuyuki; Shofie, Mohammad; Li, Yu-You

    2015-02-01

    This study was conducted to characterize the kinetics of an anaerobic process (hydrolysis, acetogenesis, acidogenesis and methanogenesis) under thermophilic (55 °C) and mesophilic (35 °C) conditions with coffee grounds and waste activated sludge (WAS) as the substrates. Special focus was given to the kinetics of propionic acid degradation to elucidate the accumulation of VFAs. Under the thermophilic condition, the methane production rate of all substrates (WAS, ground coffee and raw coffee) was about 1.5 times higher than that under the mesophilic condition. However, the effects on methane production of each substrate under the thermophilic condition differed: WAS increased by 35.8-48.2%, raw coffee decreased by 76.3-64.5% and ground coffee decreased by 74.0-57.9%. Based on the maximum reaction rate (Rmax) of each anaerobic stage obtained from the modified Gompertz model, acetogenesis was found to be the rate-limiting step for coffee grounds and WAS. This can be explained by the kinetics of propionate degradation under thermophilic condition in which a long lag-phase (more than 18 days) was observed, although the propionate concentration was only 500 mg/L. Under the mesophilic condition, acidogenesis and hydrolysis were found to be the rate-limiting step for coffee grounds and WAS, respectively. Even though reducing the particle size accelerated the methane production rate of coffee grounds, but did not change the rate-limiting step: acetogenesis in thermophilic and acidogenesis in mesophilic. PMID:25534040

  20. Closed Genome Sequence of Octadecabacter temperatus SB1, the First Mesophilic Species of the Genus Octadecabacter

    PubMed Central

    Voget, Sonja; Billerbeck, Sara; Simon, Meinhard

    2015-01-01

    The Gram-negative alphaproteobacterium Octadecabacter temperatus SB1 (DSM 26878) belongs to the marine Roseobacter clade. The genome of this strain is the smallest closed genome of the Roseobacter clade. O. temperatus SB1 is the first described nonpolar mesophilic isolate of the genus Octadecabacter and the type strain of the species. PMID:26358607

  1. Complete Genome Sequence of the Subsurface, Mesophilic Sulfate-Reducing Bacterium Desulfovibrio aespoeensis Aspo-2

    PubMed Central

    Bengtsson, Andreas; Edlund, Johanna; Rabe, Lisa; Hazen, Terry; Chakraborty, Romy; Goodwin, Lynne; Shapiro, Nicole

    2014-01-01

    Desulfovibrio aespoeensis Aspo-2, DSM 10631T, is a mesophilic, hydrogenotrophic sulfate-reducing bacterium sampled from a 600-m-deep subsurface aquifer in hard rock under the island of Äspö in southeastern Sweden. We report the genome sequence of this bacterium, which is a 3,629,109-bp chromosome; plasmids were not found. PMID:24874683

  2. Interaction between temperature and ammonia in mesophilic digesters for animal waste treatment

    E-print Network

    Angenent, Lars T.

    Interaction between temperature and ammonia in mesophilic digesters for animal waste treatment February 2009 Accepted 20 February 2009 Published online 6 March 2009 Keywords: Ammonia Anaerobic digesters (ASBRs) were operated during a period of 988 days to evaluate the effect of temperature, ammonia

  3. Sequential anaerobic-aerobic degradation of munitions waste.

    PubMed

    Ibeanusi, Victor; Jeilani, Yassin; Houston, Samantha; Doss, Danielle; Coley, Bianca

    2009-01-01

    A sequential anaerobic-aerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was studied. The results demonstrated that: (i) a complete degradation of RDX was achieved within 20 days using a consortium of bacteria from a wastewater activated sludge, (ii) RDX degradation did not occur under aerobic conditions alone, (iii) RDX-degrading bacterial strain that was isolated from the activated sludge completely degraded RDX within 2 days, and (iv) RDX- induced protein expressions were observed in the RDX-degrading bacterial strain. Based on fatty acid composition and a confirmation with a 16S rRNA analysis, the RDX-degrading bacterial strain was identified as a Bacillus pumilus-GC subgroup B. PMID:18779925

  4. Molecular interactions within the halophilic, thermophilic, and mesophilic prokaryotic ribosomal complexes: clues to environmental adaptation.

    PubMed

    Mallik, Saurav; Kundu, Sudip

    2015-01-01

    Using the available crystal structures of 50S ribosomal subunits from three prokaryotic species: Escherichia coli (mesophilic), Thermus thermophilus (thermophilic), and Haloarcula marismortui (halophilic), we have analyzed different structural features of ribosomal RNAs (rRNAs), proteins, and of their interfaces. We have correlated these structural features with the environmental adaptation strategies of the corresponding species. While dense intra-rRNA packing is observed in thermophilic, loose intra-rRNA packing is observed in halophilic (both compared to mesophilic). Interestingly, protein-rRNA interfaces of both the extremophiles are densely packed compared to that of the mesophilic. The intersubunit bridge regions are almost devoid of cavities, probably ensuring the proper formation of each bridge (by not allowing any loosely packed region nearby). During rRNA binding, the ribosomal proteins experience some structural transitions. Here, we have analyzed the intrinsically disordered and ordered regions of the ribosomal proteins, which are subjected to such transitions. The intrinsically disordered and disorder-to-order transition sites of the thermophilic and mesophilic ribosomal proteins are simultaneously (i) highly conserved and (ii) slowly evolving compared to rest of the protein structure. Although high conservation is observed at such sites of halophilic ribosomal proteins, but slow rate of evolution is absent. Such differences between thermophilic, mesophilic, and halophilic can be explained from their environmental adaptation strategy. Interestingly, a universal biophysical principle evident by a linear relationship between the free energy of interface formation, interface area, and structural changes of r-proteins during assembly is always maintained, irrespective of the environmental conditions. PMID:24697502

  5. Onsite Wastewater Treatment Systems: Aerobic Treatment Unit 

    E-print Network

    Lesikar, Bruce J.

    2008-10-31

    Aerobic units treat wastewater using the same process, only scaled down, as municipal wastewater treatment systems. This publication explains how aerobic units work, what their design requirements are, and how to maintain them....

  6. Aerobic Biotransformation of Polybrominated Diphenyl Ethers

    E-print Network

    Alvarez-Cohen, Lisa

    Aerobic Biotransformation of Polybrominated Diphenyl Ethers (PBDEs) by Bacterial Isolates K R I about their susceptibility to aerobic biotransformation. Here, we investigated the ability of aerobic transformation of tetra-, penta,- and hexa-BDEs as well as the first report of stoichiometric

  7. An Aerobic Scope Model for Estimating

    E-print Network

    Hawai'i at Manoa, University of

    An Aerobic Scope Model for Estimating Limits of Yellowfin Tuna Habitat Gen Del Raye, Kevin Weng adaptation Slide 1/12 #12;Model concept Semi-empirical model of aerobic scope Slide 2/12 Temperature (°C) Oxygen (umol/kg) VO2(ml/kgmin) #12;Model concept Semi-empirical model of aerobic scope Slide 2/12 Max

  8. Health Fitness Standards. Aerobic Endurance.

    ERIC Educational Resources Information Center

    Dotson, Chuck

    1988-01-01

    An exploration of the current thinking about levels of fitness necessary to meet health fitness standards, with particular focus on aerobic capacity, discusses major health problems, the prevalence of heart disease, how health standards are set, and how health habits change as people age. (CB)

  9. The effect of cyclic aerobic-anoxic conditions on biodegradation of benzoate.

    PubMed

    Deniz, Timur; Cinar, Ozer; Marques, Ana C; Grady, C P Leslie

    2006-04-01

    The response of a mixed microbial culture to cyclic aerobic and anoxic (denitrifying) conditions was studied in a chemostat with a 48-hour hydraulic residence time receiving a feed containing benzoate and pyruvate. When the cyclic conditions were 3-hour aerobic and 9-hour anoxic, the bacteria-degraded benzoate aerobically via the catechol 2,3-dioxygenase (C23DO) pathway. The quantity of C23DO remained constant throughout the anoxic period but decreased during the initial portion of the aerobic period before returning to the level present in the anoxic period. Anoxic biodegradation of benzoate was via benzoyl-CoA reductase, which remained constant regardless of the redox condition. The aerobic benzoate uptake capability (AeBUC) of the culture increased during the aerobic period but decreased during the anoxic period. The anoxic benzoate uptake capability (AnBUC) exhibited the opposite response. When the cycle was 6-hour aerobic and 6-hour anoxic, aerobic biodegradation of benzoate proceeded via the protocatechuate 4,5-dioxygenase (P45DO) pathway. The P45DO activity decreased early in the aerobic period, but then increased to the level present during the anoxic period. The level of benzoyl-CoA reductase was constant throughout the cycle. Furthermore, AeBUC and AnBUC responded in much the same way as in the 3/9-hour chemostat. During a 9-hour aerobic and 3-hour anoxic cycle, the culture synthesized both P45DO and C23DO, with the former having significantly higher activity. Unlike the other two cycles, AeBUC changed little during the aerobic period, although AnBUC decreased. The culture was well-adapted to the cyclic conditions as evidenced by the lack of accumulation of either substrate during any cycle tested. This suggests that cyclic aerobic-anoxic processes can be used in industrial wastewater-treatment facilities receiving significant quantities of simple aromatic compounds like benzoate. However, the results showed that the kinetics of benzoate degradation were different under aerobic and anoxic conditions, a situation that must be considered when modeling cyclic bioreactors receiving aromatic compounds. PMID:16749302

  10. Pathogen inactivation in liquid dairy manure during anaerobic and aerobic digestions

    NASA Astrophysics Data System (ADS)

    Biswas, S.; Pandey, P.; Castillo, A. R.; Vaddella, V. K.

    2014-12-01

    Controlling manure-borne pathogens such as E. coli O157:H7, Salmonella spp. and Listeria monocytogenes are crucial for protecting surface and ground water as well as mitigating risks to human health. In California dairy farms, flushing of dairy manure (mainly animal feces and urine) from freestall barns and subsequent liquid-solid manure separation is a common practice for handling animal waste. The liquid manure fraction is generally pumped into the settling ponds and it goes into aerobic and/or anaerobic lagoons for extended period of time. Considering the importance of controlling pathogens in animal waste, the objective of the study was to understand the effects of anaerobic and aerobic digestions on the survival of three human pathogens in animal waste. The pathogen inactivation was assessed at four temperatures (30, 35, 42, and 50 °C), and the relationships between temperature and pathogen decay were estimated. Results showed a steady decrease of E. coli levels in aerobic and anaerobic digestion processes over the time; however, the decay rates varied with pathogens. The effect of temperature on Salmonella spp. and Listeria monocytogenes survival was different than the E. coli survival. In thermophilic temperatures (42 and 50 °C), decay rate was considerable greater compared to the mesophilic temperatures (30 and 35°C). The E. coli log reductions at 50 °C were 2.1 in both aerobic and anaerobic digestions after 13 days of incubation. The Salmonella spp. log reductions at 50 °C were 5.5 in aerobic digestion, and 5.9 in anaerobic digestion. The Listeria monocytogenes log reductions at 50 °C were 5.0 in aerobic digestion, and 5.6 in anaerobic digestion. The log reduction of E. coli, Salmonella spp., and Listeria monocytogens at 30 °C in aerobic environment were 0.1, 4.7, and 5.6, respectively. In anaerobic environment, the corresponding reductions were 0.4, 4.3, and 5.6, respectively. We anticipate that the outcomes of the study will help improving the existing animal waste management processes to control manure-borne pathogens.

  11. Mesophilic and Thermophilic Cultures Used in Traditional Cheesemaking.

    PubMed

    Johnson, Mark E

    2013-10-01

    Most cheese varieties require acidification of milk by a select group of bacteria called starters. They ferment lactose to lactic acid and in so doing aid the cheesemaker in developing the desired texture as well as acidity of the cheese. However, while other microorganisms play the major role in flavor development of cheese, it is the starter that sets the stage for quality cheese manufacture. Starters were traditionally derived from the native microflora of the milk, but this practice is almost unheard of today. With the advent of better hygienic milking practices and industrialized cheesemaking, there was a need for more uniformity and reliable sources of the starter culture. Today's starters are produced by companies specializing in their production as well as in the development of new strains for cheesemakers. The choice of starter for the manufacture of a specific cheese is dictated by the cheesemaking protocol, but it is also governed by the need to produce cheese with desired physical attributes. The properties of the starter that make it possible to do so help drive innovation in developing new potential choices in starter cultures. Indeed, the demands for predictable and reliable rates and extent of acidification of milk for cheesemaking and flavor development are as key for successful cheesemaking today with artisanal cheesemakers as they are for larger, more industrial-scale cheesemakers. PMID:26184811

  12. Aerobic bacterial flora of addled raptor eggs in Saskatchewan.

    PubMed

    Houston, C S; Saunders, J R; Crawford, R D

    1997-04-01

    In south-central Saskatchewan, Canada, in 1986, 1987 and 1989, the aerobic bacterial flora was evaluated from 75 unhatched raptor eggs of three species: 42 of the Swainson's hawk (Buteo Swainsoni), 21 of the ferruginous hawk (Buteo regalis), and 12 of the great horned owl (Bubo virginianus). In addled Swainson's hawk eggs, the most common bacterial genera were Enterobacter (18 eggs), Escherichia (12), and Streptococcus (10). Seven great horned owl eggs and six ferruginous hawk eggs also contained Escherichia coli. Salmonella spp. were not isolated. These bacteria were interpreted as secondary contaminants and not the primary cause of reproductive failure. PMID:9131569

  13. Differences in the catalytic mechanisms of mesophilic and thermophilic indole-3-glycerol phosphate synthase enzymes at their adaptive temperatures

    SciTech Connect

    Zaccardi, Margot J.; Mannweiler, Olga; Boehr, David D.

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Catalytic mechanisms of thermophilic-mesophilic enzymes may differ. Black-Right-Pointing-Pointer Product release is rate-determining for thermophilic IGPS at low temperatures. Black-Right-Pointing-Pointer But at higher temperatures, proton transfer from the general acid is rate-limiting. Black-Right-Pointing-Pointer Rate-determining step is different still for mesophilic IGPS. Black-Right-Pointing-Pointer Both chemical and physical steps of catalysis are important for temperature adaptation. -- Abstract: Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order to cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic-mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25 Degree-Sign C for thermophilic IGPS, near its adaptive temperature (75 Degree-Sign C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO{sub 2} release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards.

  14. Swimming bacteria power microscopic gears

    SciTech Connect

    Sokolov, Andrey; Apodaca, Mario M.; Grzybowski, Bartosz A.; Aranson, Igor S.

    2010-01-19

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be “rectified” under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears’ angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  15. Swimming bacteria power microscopic gears

    PubMed Central

    Sokolov, Andrey; Apodaca, Mario M.; Grzybowski, Bartosz A.; Aranson, Igor S.

    2010-01-01

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be “rectified” under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears’ angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms. PMID:20080560

  16. Swimming bacteria power microscopic gears.

    SciTech Connect

    Sokolov, A.; Apodaca, M. M.; Grzybowski, B. A.; Aranson, I. S.; Materials Science Division; Princeton Univ.; Northwestern Univ.

    2010-01-19

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be 'rectified' under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  17. Functional responses and adaptation of mesophilic microbial communities to psychrophilic anaerobic digestion.

    PubMed

    Gunnigle, Eoin; Nielsen, Jeppe L; Fuszard, Matthew; Botting, Catherine H; Sheahan, Jerome; O'Flaherty, Vincent; Abram, Florence

    2015-12-01

    Psychrophilic (<20°C) anaerobic digestion (AD) represents an attractive alternative to mesophilic wastewater treatment. In order to investigate the AD microbiome response to temperature change, with particular emphasis on methanogenic archaea, duplicate laboratory-scale AD bioreactors were operated at 37°C followed by a temperature drop to 15°C. A volatile fatty acid-based wastewater (composed of propionic acid, butyric acid, acetic acid and ethanol) was used to provide substrates representing the later stages of AD. Community structure was monitored using 16S rRNA gene clone libraries, as well as DNA and cDNA-based DGGE analysis, while the abundance of relevant methanogens was followed using qPCR. In addition, metaproteomics, microautoradiography-fluorescence in situ hybridization, and methanogenic activity measurements were employed to investigate microbial activities and functions. Methanomicrobiales abundance increased at low temperature, which correlated with an increased contribution of CH4 production from hydrogenotrophic methanogenesis at 15°C. Methanosarcinales utilized acetate and H2/CO2 as CH4 precursors at both temperatures and a partial shift from acetoclastic to hydrogenotrophic methanogenesis was observed for this archaeal population at 15°C. An upregulation of protein expression was reported at low temperature as well as the detection of chaperones indicating that mesophilic communities experienced stress during long-term exposure to 15°C. Overall, changes in microbial community structure and function were found to underpin the adaptation of mesophilic sludge to psychrophilic AD. PMID:26507125

  18. Incidence of mesophilic Aeromonas within a public drinking water supply in north-east Scotland.

    PubMed

    Gavriel, A A; Landre, J P; Lamb, A J

    1998-03-01

    The motile mesophilic Aeromonas are ubiquitous to a wide variety of aquatic environments including drinking water distribution systems. Concern over the presence of mesophilic Aeromonas in public drinking water supplies has been expressed in recent years as it has been regarded as a pathogenic organism of importance in gastroenteritis. A major drinking water distribution system in north-east Scotland was monitored over a 12 month period to determine the prevalence of mesophilic Aeromonas. These data were examined in relation to chlorine concentration, pH, temperature, rainfall and the standard bacteriological indicators of water quality. Aeromonas were isolated to varying degrees from 21 of the 31 reservoirs investigated. The maximum recovery observed during the study was 605 cfu in 300 ml. The probability of isolation generally decreased with increasing levels of chlorination, although this oxidant was found to be ineffective in many reservoirs. Certain reservoirs with poor chlorination profiles yielded very few isolates, whereas some highly chlorinated sites liberated Aeromonas frequently and in relatively high numbers. A seasonal pattern in the incidence of Aeromonas emerged with infrequent isolation during the winter period increasing to a peak during the summer, with most isolates recovered when water temperature was > 12 degrees C. An association was demonstrated between the pattern of Aeromonas isolations and that of rainfall. No relationship was apparent between incidence of Aeromonas and total heterotrophic plate counts. PMID:9721643

  19. 454-Pyrosequencing Reveals Microbial Community Structure and Composition in a Mesophilic UAFB System Treating PTA Wastewater.

    PubMed

    Ma, Kai-Li; Li, Xiang-Kun; Wang, Ke; Zhou, He-Xi; Meng, Ling-Wei; Zhang, Jie

    2015-11-01

    To well understand the community structure and composition of mesophilic microorganisms in anaerobic system fed with PTA wastewater, an up-flow anaerobic fixed bed reactor was continuously run at 33 and 37 °C for 75 and 60 days, respectively. Both fluorescence in situ hybridization analysis and 454-pyrosequencing were applied to investigate the microbial distinction within mesophilic ranges. A preferable performance was achieved at 37 than 33 °C. The taxonomic complexities of two samples were further compared at phylum, class, and genus levels. Notably, microbial diversity differed a lot and the change of populations was observed mainly in the shared OTUs. Genus level analysis showed that when temperature was increased to 37 °C, the abundance of Thauera and Hydrogenophaga (?-Proteobacteria) decreased by 93.75 and 61.47 %, respectively, whereas that of Syntrophorhabdus (?-Proteobacteria) increased from 4.93 to 16.01 %. Furthermore, the dominant archaeal Methanobacterium at both temperatures indicated the prevailing contribution of hydrogenotrophic methanogens in mesophilic anaerobic system. PMID:26223650

  20. Performance evaluation of a completely stirred anaerobic reactor treating pig manure at a low range of mesophilic conditions

    SciTech Connect

    Guo, Jianbin; Dong, Renjie; Clemens, Joachim; Wang, Wei

    2013-11-15

    Highlights: • The biogas process can run stably at 20 °C at extremely low OLR after long-term acclimation of bacteria. • A biogas plant running at 28 °C seems as efficient as that operated at 38 °C at low OLR of 1.3 g ODM L{sup ?1} d{sup ?1}. • Lower temperature operation is inadvisable for the commercial biogas plant running at rather high OLR. • The estimated sludge yield at 28 °C is higher than that at 38 °C. - Abstract: Many Chinese biogas plants run in the lower range of mesophilic conditions. This study evaluated the performance of a completely stirred anaerobic reactor treating pig manure at different temperatures (20, 28 and 38 °C). The start-up phase of the reactor at 20 °C was very long and extremely poor performance was observed with increasing organic loading rate (OLR). At an OLR of 4.3 g ODM L{sup ?1} d{sup ?1}, methane production at 28 °C was comparable (3% less) with that at 38 °C, but the risk of acidification was high at 28 °C. At low OLR (1.3 g ODM L{sup ?1} d{sup ?1}), the biogas process appeared stable at 28 °C and gave same methane yields as compared to the reactor operating at 38 °C. The estimated sludge yield at 28 °C was 0.065 g VSS g{sup ?1} COD{sub removed,} which was higher than that at 38 °C (0.016 g VSS g{sup ?1} COD{sub removed})

  1. Kinetics of sulfate and hydrogen uptake by the thermophilic sulfate-reducing bacteria thermodesulfobacterium sp. Strain JSP and thermodesulfovibrio sp. Strain R1Ha3

    PubMed

    Sonne-Hansen; Westermann; Ahring

    1999-03-01

    Half-saturation constants (Km), maximum uptake rates (Vmax), and threshold concentrations for sulfate and hydrogen were determined for two thermophilic sulfate-reducing bacteria (SRB) in an incubation system without headspace. Km values determined for the thermophilic SRB were similar to the constants described for mesophilic SRB isolated from environments with low sulfate concentrations. PMID:10049897

  2. Kinetics of Sulfate and Hydrogen Uptake by the Thermophilic Sulfate-Reducing Bacteria Thermodesulfobacterium sp. Strain JSP and Thermodesulfovibrio sp. Strain R1Ha3

    PubMed Central

    Sonne-Hansen, Jacob; Westermann, Peter; Ahring, Birgitte K.

    1999-01-01

    Half-saturation constants (Km), maximum uptake rates (Vmax), and threshold concentrations for sulfate and hydrogen were determined for two thermophilic sulfate-reducing bacteria (SRB) in an incubation system without headspace. Km values determined for the thermophilic SRB were similar to the constants described for mesophilic SRB isolated from environments with low sulfate concentrations. PMID:10049897

  3. Bacteria in Crude Oil Survived Autoclaving and Stimulated Differentially by Exogenous Bacteria

    PubMed Central

    Guo, Peng; Chi, Chang-Qiao; Chen, Jian; Wang, Xing-Biao; Tang, Yue-Qin; Wu, Xiao-Lei; Liu, Chun-Zhong

    2012-01-01

    Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR). However, it is not entirely clear if “endogenous” bacteria (e.g., spores) in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the “exogenous” bacterial strains. To test this, we inoculated autoclaved crude oil medium with six exogenous bacterial strains (three Dietzia strains, two Acinetobacter strains, and one Pseudomonas strain). The survival of the spore-forming Bacillus and Paenibacillus and the non-spore-forming mesophilic Pseudomonas, Dietzia, Alcaligenes, and Microbacterium was detected using a 16S rRNA gene clone library and terminal restriction fragment length polymorphism (T-RFLP) analysis. However, neither bacteria nor bacterial activity was detected in three controls consisting of non-inoculated autoclaved crude oil medium. These results suggest that detection of endogenous bacteria was stimulated by the six inoculated strains. In addition, inoculation with Acinetobacter spp. stimulated detection of Bacillus, while inoculation with Dietzia spp. and Pseudomonas sp. stimulated the detection of more Pseudomonas. In contrast, similar exogenous bacteria stimulated similar endogenous bacteria at the genus level. Based on these results, special emphasis should be applied to evaluate the influence of bacteria capable of surviving autoclaving on the hydrocarbon-degrading abilities of exogenous bacteria, in particular, with regard to bioaugmentation and MEOR. Bioaugmentation and MEOR technologies could then be developed to more accurately direct the growth of specific endogenous bacteria that may then improve the efficiency of treatment or recovery of crude oil. PMID:23028421

  4. Toxic effects of butyl elastomers on aerobic methane oxidation

    NASA Astrophysics Data System (ADS)

    Niemann, Helge; Steinle, Lea I.; Blees, Jan H.; Krause, Stefan; Bussmann, Ingeborg; Lehmann, Moritz F.; Treude, Tina

    2013-04-01

    Large quantities of the potent greenhouse gas methane are liberated into the water column of marine and lacustrine environments where it may be consumed by aerobic methane oxidising bacteria before reaching the atmosphere.The reliable quantification of aerobic methane oxidation (MOx) rates is consequently of paramount importance for estimating methane budgets and to understand the controls on water column methane cycling. A widely used set of methods for measuring MOx rates is based on the incubation of water samples during which the consumption of methane is monitored, for instance with radio-tracer assays. Typically, incubation vessels are sealed with butyl rubber stoppers because these elastomers are essentially impermeable for gases at the relevant time scales. We tested the effect of different stopper materials (unmodified- and halogenated butyl rubber) on MOx activity in environmental samples and in cultures of methane oxidising bacteria. MOx rates in samples sealed with unmodified butyl rubber were > 75% lower compared to parallel incubations with halogenated butyl rubber seals, suggesting inhibiting/toxic effects associated with the use of unmodified butyl elastomers. To further explore the cause of these effects, we analysed aqueous extracts of the different stoppers. Halogenated butyl rubber stoppers appeared to bleed off comparably little amounts of organics. In stark contrast, extracts of unmodified butyl rubber were contaminated with various organic compounds including potential bactericides such as benzyltoluenes, phenylalkanes and benzuothiazoles. We also found tetramethylthiourea, a scavenger of active oxygen species, which may inhibit the MOx pathway.

  5. Aerobic moving bed biofilm reactor treating thermomechanical pulping whitewater under thermophilic conditions.

    PubMed

    Jahren, Sigrun J; Rintala, Jukka A; Odegaard, Hallvard

    2002-02-01

    The continuously operated laboratory scale Kaldnes moving bed biofilm reactor (MBBR) was used for thermophilic (55 degrees C) aerobic treatment of TMP whitewater. In the MBBR, the biomass is grown on carrier elements that move along with the water in the reactor. Inoculation with mesophilic activated sludge gave 60-65% SCOD removal from the first day onwards. During the 107 days of experiment, the 60-65% SCOD removals were achieved at organic loading rates of 2.5-3.5 kg SCODm(-3) d(-1), the highest loading rates applied during the run and HRT of 13-22h. Carbohydrates, which contributed to 50-60% of the influent SCOD. were removed by 90-95%, while less than 15% of the lignin-like material (30-35% of SCODin) was removed. The sludge yield was 0.23g VSSg SCOD(-1)removed. The results show that the aerobic biofilm process can be successfully operated under thermophilic conditions. PMID:11848344

  6. Methanotrophic bacteria.

    PubMed Central

    Hanson, R S; Hanson, T E

    1996-01-01

    Methane-utilizing bacteria (methanotrophs) are a diverse group of gram-negative bacteria that are related to other members of the Proteobacteria. These bacteria are classified into three groups based on the pathways used for assimilation of formaldehyde, the major source of cell carbon, and other physiological and morphological features. The type I and type X methanotrophs are found within the gamma subdivision of the Proteobacteria and employ the ribulose monophosphate pathway for formaldehyde assimilation, whereas type II methanotrophs, which employ the serine pathway for formaldehyde assimilation, form a coherent cluster within the beta subdivision of the Proteobacteria. Methanotrophic bacteria are ubiquitous. The growth of type II bacteria appears to be favored in environments that contain relatively high levels of methane, low levels of dissolved oxygen, and limiting concentrations of combined nitrogen and/or copper. Type I methanotrophs appear to be dominant in environments in which methane is limiting and combined nitrogen and copper levels are relatively high. These bacteria serve as biofilters for the oxidation of methane produced in anaerobic environments, and when oxygen is present in soils, atmospheric methane is oxidized. Their activities in nature are greatly influenced by agricultural practices and other human activities. Recent evidence indicates that naturally occurring, uncultured methanotrophs represent new genera. Methanotrophs that are capable of oxidizing methane at atmospheric levels exhibit methane oxidation kinetics different from those of methanotrophs available in pure cultures. A limited number of methanotrophs have the genetic capacity to synthesize a soluble methane monooxygenase which catalyzes the rapid oxidation of environmental pollutants including trichloroethylene. PMID:8801441

  7. SUPPLEMENTARY MATERIALS High current densities enable exoelectrogens to outcompete aerobic

    E-print Network

    SUPPLEMENTARY MATERIALS High current densities enable exoelectrogens to outcompete aerobic to better understand substrate consumption by aerobic heterotrophs at open circuit compared that aerobic heterotrophs could not oxidize the same amount of s

  8. Scouring Potential of Mesophile Acidic Proteases of Pseudomonas aeruginosa for Grey Cotton Fabrics

    NASA Astrophysics Data System (ADS)

    Saravanan, D.

    2013-04-01

    Mesophile, acidic proteases were produced using the microbial source, Pseudomonas aeruginosa, with wider thermal tolerances. Process conditions of scouring treatment were optimized using Taguchi method for optimum temperature, time, pH and concentration of protease. Treatment with the protease lower weight loss values compared to the alkali scouring, however, significant improvement in the absorbency compared to the grey samples was observed. Large amounts of pectin left out in the samples resulted in higher extractable impurities, substantiated by the FTIR results. Relatively, lower reduction in the tear strengths was observed in both warp and weft directions after protease treatment of the cotton fabrics.

  9. An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia

    PubMed Central

    Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R.; Cook, Gregory M.

    2014-01-01

    Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD+/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments. PMID:25049411

  10. Water quality parameters and total aerobic bacterial and vibrionaceae loads in eastern oysters (Crassostrea virginica) from oyster gardening sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oyster gardening is a practice designed to restore habitat for marine life and to improve water quality. This study determined physical and chemical water quality parameters at two oyster gardening sites in the Delaware Inland Bays and compared them with total aerobic bacteria and Vibrionaceae conc...

  11. Skeletal muscle hypertrophy after aerobic exercise training.

    PubMed

    Konopka, Adam R; Harber, Matthew P

    2014-04-01

    Current dogma suggests that aerobic exercise training has minimal effects on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise countermeasures for populations prone to muscle loss. PMID:24508740

  12. Aerobic Dancing--A Rhythmic Sport.

    ERIC Educational Resources Information Center

    Sorensen, Jacki

    Fitness programs now and in the future must offer built-in cardiovascular conditioning, variety, novelty, and change to meet the physical, mental, and emotional needs of our society. Aerobic dancing (dancing designed to train and strengthen the heart, lungs, and vascular system) is one of the first indoor group Aerobic exercise programs designed…

  13. STANDARDIZING AEROBIC INCUBATION METHODS: IS IT POSSIBLE?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic incubation methods have been widely used to assess soil nitrogen (N) mineralization, but standardized protocols are lacking. A single silt loam soil (Catlin silt loam; fine-silty, mixed, superactive, mesic, Oxyaquic Arguidoll) was subjected to aerobic incubation at six USDA-ARS locations usi...

  14. Aerobic Fitness for the Moderately Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    Intended for physical education teachers, the booklet offers ideas for incorporating aerobic conditioning into programs for moderately mentally retarded students. An explanation of aerobic fitness and its benefits is followed by information on initiating a fitness program with evaluation of height, weight, body fat, resting heart rate, and…

  15. Metagenomics of Hydrocarbon Resource Environments Indicates Aerobic Taxa and Genes to be Unexpectedly Common

    PubMed Central

    2013-01-01

    Oil in subsurface reservoirs is biodegraded by resident microbial communities. Water-mediated, anaerobic conversion of hydrocarbons to methane and CO2, catalyzed by syntrophic bacteria and methanogenic archaea, is thought to be one of the dominant processes. We compared 160 microbial community compositions in ten hydrocarbon resource environments (HREs) and sequenced twelve metagenomes to characterize their metabolic potential. Although anaerobic communities were common, cores from oil sands and coal beds had unexpectedly high proportions of aerobic hydrocarbon-degrading bacteria. Likewise, most metagenomes had high proportions of genes for enzymes involved in aerobic hydrocarbon metabolism. Hence, although HREs may have been strictly anaerobic and typically methanogenic for much of their history, this may not hold today for coal beds and for the Alberta oil sands, one of the largest remaining oil reservoirs in the world. This finding may influence strategies to recover energy or chemicals from these HREs by in situ microbial processes. PMID:23889694

  16. Could petroleum biodegradation be a joint achievement of aerobic and anaerobic microrganisms in deep sea reservoirs?

    PubMed Central

    2011-01-01

    Several studies suggest that petroleum biodegradation can be achieved by either aerobic or anaerobic microorganisms, depending on oxygen input or other electron acceptors and appropriate nutrients. Evidence from in vitro experiments with samples of petroleum formation water and oils from Pampo Field indicate that petroleum biodegradation is more likely to be a joint achievement of both aerobic and anaerobic bacterial consortium, refining our previous observations of aerobic degradation. The aerobic consortium depleted, in decreasing order, hydrocarbons > hopanes > steranes > tricyclic terpanes while the anaerobic consortium depleted hydrocarbons > steranes > hopanes > tricyclic terpanes. The oxygen content of the mixed consortia was measured from time to time revealing alternating periods of microaerobicity (O2 ~0.8 mg.L-1) and of aerobicity (O2~6.0 mg.L-1). In this experiment, the petroleum biodegradation changed from time to time, alternating periods of biodegradation similar to the aerobic process and periods of biodegradation similar to the anaerobic process. The consortia showed preferences for metabolizing hydrocarbons > hopanes > steranes > tricyclic terpanes during a 90-day period, after which this trend changed and steranes were more biodegraded than hopanes. The analysis of aerobic oil degrading microbiota by the 16S rRNA gene clone library detected the presence of Bacillus, Brevibacterium, Mesorhizobium and Achromobacter, and the analysis of the anaerobic oil degrading microbiota using the same technique detected the presence of Bacillus and Acinetobacter (facultative strains). In the mixed consortia Stenotrophomonas, Brevibacterium, Bacillus, Rhizobium, Achromobacter and 5% uncultured bacteria were detected. This is certainly a new contribution to the study of reservoir biodegradation processes, combining two of the more important accepted hypotheses. PMID:22196374

  17. Bacteria Counter

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Science Applications, Inc.'s ATP Photometer makes a rapid and accurate count of the bacteria in a body fluid sample. Instrument provides information on the presence and quantity of bacteria by measuring the amount of light emitted by the reaction between two substances. Substances are ATP adenosine triphosphate and luciferase. The reactants are applied to a human body sample and the ATP Photometer observes the intensity of the light emitted displaying its findings in a numerical output. Total time lapse is usually less than 10 minutes, which represents a significant time savings in comparison of other techniques. Other applications are measuring organisms in fresh and ocean waters, determining bacterial contamination of foodstuffs, biological process control in the beverage industry, and in assay of activated sewage sludge.

  18. Mesophilic co-digestion of palm oil mill effluent and empty fruit bunches.

    PubMed

    Kim, Sang-Hyoun; Choi, Seon-Mi; Ju, Hyun-Jun; Jung, Jin-Young

    2013-01-01

    The palm oil mill industry generates palm oil mill effluent (POME) and empty fruit bunches (EFB) as by-products. This study reports the mesophilic co-digestion of POME with EFB. The biochemical methane potential (BMP) of POME and EFB was 0.397 L CH4/g volatile solids (VS) and 0.264 L CH4/g VS, respectively. In a series of batch tests at various EFB to POME ratios, the maximum methane production rate was achieved at an EFB:POME ratio of 0.25-0.31:1. Performance data from lab-scale digesters confirmed the positive synergism by the addition of EFB to POME, which was attributed to the balanced chemical composition, for example the chemical oxygen demand (COD) to total Kjeldahl nitrogen (TKN) ratio. The EFB addition enhanced the acceptable organic loading rate, methane production, COD removal, and microbial activity. The mesophilic co-digestion of POME and EFB promises to be a viable recycling method to alleviate pollution problems and recover renewable energy in the palm oil mill industry. PMID:24350470

  19. Mesophilic and thermophilic anaerobic laboratory-scale digestion of Nannochloropsis microalga residues.

    PubMed

    Kinnunen, H V; Koskinen, P E P; Rintala, J

    2014-03-01

    This paper studies methane production using a marine microalga, Nannochloropsis sp. residue from biodiesel production. Residue cake from Nannochloropsis, oils wet-extracted, had a methane potential of 482LCH4kg(-1) volatile solids (VS) in batch assays. However, when dry-extracted, the methane potential of residue cake was only 194LCH4kg(-1) VS. In semi-continuous reactor trials with dry-extracted residue cake, a thermophilic reactor produced 48% higher methane yield (220LCH4kg(-1)VS) than a mesophilic reactor (149LCH4kg(-1)VS). The thermophilic reactor was apparently inhibited due to ammonia with organic loading rate (OLR) of 2kgVSm(-3)d(-1) (hydraulic retention time (HRT) 46d), whereas the mesophilic reactor performed with OLR of 3kgVSm(-3)d(-1) (HRT 30d). Algal salt content did not inhibit digestion. Additional methane (18-33% of primary digester yield) was produced during 100d post-digestion. PMID:24462882

  20. Exploring Local Flexibility/Rigidity in Psychrophilic and Mesophilic Carbonic Anhydrases

    PubMed Central

    Chiuri, R.; Maiorano, G.; Rizzello, A.; del Mercato, L.L.; Cingolani, R.; Rinaldi, R.; Maffia, M.; Pompa, P.P.

    2009-01-01

    Molecular flexibility and rigidity are required to determine the function and specificity of protein molecules. Some psychrophilic enzymes demonstrate a higher catalytic efficiency at low temperatures, compared to the efficiency demonstrated by their meso/thermophilic homologous. The emerging picture suggests that such enzymes have an improved flexibility of the structural catalytic components, whereas other protein regions far from functional sites may be even more rigid than those of their mesophilic counterparts. To gain a deeper insight in the analysis of the activity-flexibility/rigidity relationship in protein structure, psychrophilic carbonic anhydrase of the Antarctic teleost Chionodraco hamatus has been compared with carbonic anhydrase II of Bos taurus through fluorescence studies, three-dimensional modeling, and activity analyses. Data demonstrated that the cold-adapted enzyme exhibits an increased catalytic efficiency at low and moderate temperatures and, more interestingly, a local flexibility in the region that controls the correct folding of the catalytic architecture, as well as a rigidity in the hydrophobic core. The opposite result was observed in the mesophilic counterpart. These results suggest a clear relationship between the activity and the presence of flexible and rigid protein substructures that may be useful in rational molecular and drug design of a class of enzymes playing a key role in pathologic processes. PMID:19217874

  1. Enzymes and genes involved in aerobic alkane degradation

    PubMed Central

    Wang, Wanpeng; Shao, Zongze

    2013-01-01

    Alkanes are major constituents of crude oil. They are also present at low concentrations in diverse non-contaminated because many living organisms produce them as chemo-attractants or as protecting agents against water loss. Alkane degradation is a widespread phenomenon in nature. The numerous microorganisms, both prokaryotic and eukaryotic, capable of utilizing alkanes as a carbon and energy source, have been isolated and characterized. This review summarizes the current knowledge of how bacteria metabolize alkanes aerobically, with a particular emphasis on the oxidation of long-chain alkanes, including factors that are responsible for chemotaxis to alkanes, transport across cell membrane of alkanes, the regulation of alkane degradation gene and initial oxidation. PMID:23755043

  2. Genome sequence of the mesophilic Thermotogales bacterium Mesotoga prima MesG1.Ag.4.2 reveals the largest Thermotogales genome to date.

    PubMed

    Zhaxybayeva, Olga; Swithers, Kristen S; Foght, Julia; Green, Anna G; Bruce, David; Detter, Chris; Han, Shunsheng; Teshima, Hazuki; Han, James; Woyke, Tanja; Pitluck, Sam; Nolan, Matt; Ivanova, Natalia; Pati, Amrita; Land, Miriam L; Dlutek, Marlena; Doolittle, W Ford; Noll, Kenneth M; Nesbø, Camilla L

    2012-01-01

    Here we describe the genome of Mesotoga prima MesG1.Ag4.2, the first genome of a mesophilic Thermotogales bacterium. Mesotoga prima was isolated from a polychlorinated biphenyl (PCB)-dechlorinating enrichment culture from Baltimore Harbor sediments. Its 2.97 Mb genome is considerably larger than any previously sequenced Thermotogales genomes, which range between 1.86 and 2.30 Mb. This larger size is due to both higher numbers of protein-coding genes and larger intergenic regions. In particular, the M. prima genome contains more genes for proteins involved in regulatory functions, for instance those involved in regulation of transcription. Together with its closest relative, Kosmotoga olearia, it also encodes different types of proteins involved in environmental and cell-cell interactions as compared with other Thermotogales bacteria. Amino acid composition analysis of M. prima proteins implies that this lineage has inhabited low-temperature environments for a long time. A large fraction of the M. prima genome has been acquired by lateral gene transfer (LGT): a DarkHorse analysis suggests that 766 (32%) of predicted protein-coding genes have been involved in LGT after Mesotoga diverged from the other Thermotogales lineages. A notable example of a lineage-specific LGT event is a reductive dehalogenase gene-a key enzyme in dehalorespiration, indicating M. prima may have a more active role in PCB dechlorination than was previously assumed. PMID:22798451

  3. Genome Sequence of the Mesophilic Thermotogales Bacterium Mesotoga prima MesG1.Ag.4.2 Reveals the Largest Thermotogales Genome To Date

    SciTech Connect

    Zhaxybayeva, Olga; Swithers, Kristen S; Foght, Julia; Green, Anna G.; Bruce, David; Detter, J. Chris; Han, Cliff; Teshima, Hazuki; Han, James; Woyke, Tanja; Pitluck, Sam; Nolan, Matt; Ivanova, N; Pati, Amrita; Land, Miriam L; Dlutek, Marlena; Doolittle, W. Ford; Noll, Kenneth M; Nesbo, Camilla

    2012-01-01

    Here we describe the genome of Mesotoga prima MesG1.Ag4.2, the first genome of a mesophilic Thermotogales bacterium. Mesotoga prima was isolated from a polychlorinated biphenyl (PCB)-dechlorinating enrichment culture from Baltimore Harbor sediments. Its 2.97 Mb genome is considerably larger than any previously sequenced Thermotogales genomes, which range between 1.86 and 2.30 Mb. This larger size is due to both higher numbers of protein-coding genes and larger intergenic regions. In particular, the M. prima genome contains more genes for proteins involved in regulatory functions, for instance those involved in regulation of transcription. Together with its closest relative, Kosmotoga olearia, it also encodes different types of proteins involved in environmental and cell-cell interactions as compared with other Thermotogales bacteria. Amino acid composition analysis of M. prima proteins implies that this lineage has inhabited low-temperature environments for a long time. A large fraction of the M. prima genome has been acquired by lateral gene transfer (LGT): a DarkHorse analysis suggests that 766 (32%) of predicted protein-coding genes have been involved in LGT after Mesotoga diverged from the other Thermotogales lineages. A notable example of a lineage-specific LGT event is a reductive dehalogenase gene - a key enzyme in dehalorespiration, indicating M. prima may have a more active role in PCB dechlorination than was previously assumed.

  4. Aerobic and nitrite-dependent methane-oxidizing microorganisms in sediments of freshwater lakes on the Yunnan Plateau.

    PubMed

    Liu, Yong; Zhang, Jingxu; Zhao, Lei; Li, Yuzhao; Yang, Yuyin; Xie, Shuguang

    2015-03-01

    Both aerobic methane-oxidizing bacteria (MOB) and nitrite-dependent anaerobic methane oxidation (n-damo) bacteria can play an important role in mitigating the methane emission produced in anoxic sediment layers to the atmosphere. However, the environmental factors regulating the distribution of these methane-oxidizing microorganisms in lacustrine ecosystems remain essentially unclear. The present study investigated the distribution of aerobic MOB and n-damo bacteria in sediments of various freshwater lakes on the Yunnan Plateau (China). Quantitative PCR assay and clone library analysis illustrated the spatial variations in the abundances and structures of aerobic MOB and n-damo bacterial communities. Type I MOB (Methylosoma and Methylobacter) and type II MOB (Methylocystis) were detected, while type I MOB was more abundant than type II MOB. Lake sediments n-damo bacterial communities were composed of novel Methylomirabilis oxyfera-like pmoA genes. Lake sediments in the same geographic region could share a relatively similar aerobic MOB community structure. Moreover, Pearson's correlation analysis indicated that n-damo pmoA gene diversity showed a positive correlation with the ratio of organic matter to total nitrogen in lake sediment. PMID:25698510

  5. Draft Genome Sequence of Leptolinea tardivitalis YMTK-2, a Mesophilic Anaerobe from the Chloroflexi Class Anaerolineae

    PubMed Central

    Ward, Lewis M.; Pace, Laura A.; Fischer, Woodward W.

    2015-01-01

    We present the draft genome sequence of Leptolinea tardivitalis YMTK-2, a member of the Chloroflexi phylum. This organism was initially characterized as a strictly anaerobic nonmotile fermenter; however, genome analysis demonstrates that it encodes for a flagella and might be capable of aerobic respiration. PMID:26586893

  6. Draft Genome Sequence of Leptolinea tardivitalis YMTK-2, a Mesophilic Anaerobe from the Chloroflexi Class Anaerolineae.

    PubMed

    Ward, Lewis M; Hemp, James; Pace, Laura A; Fischer, Woodward W

    2015-01-01

    We present the draft genome sequence of Leptolinea tardivitalis YMTK-2, a member of the Chloroflexi phylum. This organism was initially characterized as a strictly anaerobic nonmotile fermenter; however, genome analysis demonstrates that it encodes for a flagella and might be capable of aerobic respiration. PMID:26586893

  7. The Energetics of Aerobic versus Anaerobic Respiration.

    ERIC Educational Resources Information Center

    Champion, Timothy D.; Schwenz, Richard W.

    1990-01-01

    Background information, laboratory procedures, and a discussion of the results of an experiment designed to investigate the difference in energy gained from the aerobic and anaerobic oxidation of glucose are presented. Sample experimental and calculated data are included. (CW)

  8. Complete Genome Sequence of Methanoregula formicica SMSPT, a Mesophilic Hydrogenotrophic Methanogen Isolated from a Methanogenic Upflow Anaerobic Sludge Blanket Reactor

    PubMed Central

    Yamamoto, Kyosuke; Cadillo-Quiroz, Hinsby; Imachi, Hiroyuki; Kyrpides, Nikos; Woyke, Tanja; Goodwin, Lynne; Zinder, Stephen H.; Kamagata, Yoichi

    2014-01-01

    Methanoregula formicica SMSPT is a mesophilic H2/formate-utilizing methanogenic archaeon and a representative of the family Methanoregulaceae, a recently proposed novel family within the order Methanomicrobiales. Here, we report a 2.8-Mb complete genome sequence of this methanogenic archaeon. PMID:25189582

  9. Column bioleaching of uranium embedded in granite porphyry by a mesophilic acidophilic consortium.

    PubMed

    Qiu, Guanzhou; Li, Qian; Yu, Runlan; Sun, Zhanxue; Liu, Yajie; Chen, Miao; Yin, Huaqun; Zhang, Yage; Liang, Yili; Xu, Lingling; Sun, Limin; Liu, Xueduan

    2011-04-01

    A mesophilic acidophilic consortium was enriched from acid mine drainage samples collected from several uranium mines in China. The performance of the consortium in column bioleaching of low-grade uranium embedded in granite porphyry was investigated. The influences of several chemical parameters on uranium extraction in column reactor were also investigated. A uranium recovery of 96.82% was achieved in 97 days column leaching process including 33 days acid pre-leaching stage and 64 days bioleaching stage. It was reflected that indirect leaching mechanism took precedence over direct. Furthermore, the bacterial community structure was analyzed by using Amplified Ribosomal DNA Restriction Analysis. The results showed that microorganisms on the residual surface were more diverse than that in the solution. Acidithiobacillus ferrooxidans was the dominant species in the solution and Leptospirillum ferriphilum on the residual surface. PMID:21316943

  10. Effect of leachate recirculation on mesophilic anaerobic digestion of food waste.

    PubMed

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin J

    2012-03-01

    The effects of using untreated leachate for supplemental water addition and liquid recirculation on anaerobic digestion of food waste was evaluated by combining cyclic water recycle operations with batch mesophilic biochemical methane potential (BMP) assays. Cyclic BMP assays indicated that using an appropriate fraction of recycled leachate and fresh make up water can stimulate methanogenic activity and enhance biogas production. Conversely increasing the percentage of recycled leachate in the make up water eventually causes methanogenic inhibition and decrease in the rate of food waste stabilization. The decrease in activity is exacerbated as the number cycles increases. Inhibition is possibly attributed to accumulation and elevated concentrations of ammonia as well as other waste by products in the recycled leachate that inhibit methanogenesis. PMID:22088957

  11. High resolution structure of the large ribosomal subunit from a Mesophilic Eubacterium

    SciTech Connect

    Harms, Joerg; Schluenzen, Frank; Zarivach, Raz; Bashan, Anat; Gat, Sharon; Agmon, Ilana; Bartels, Heike; Franceschi, Francois; Yonath, Ada

    2009-10-07

    We describe the high resolution structure of the large ribosomal subunit from Deinococcus radiodurans (D50S), a gram-positive mesophile suitable for binding of antibiotics and functionally relevant ligands. The over-all structure of D50S is similar to that from the archae bacterium Haloarcula marismortui (H50S); however, a detailed comparison revealed significant differences, for example, in the orientation of nucleotides in peptidyl transferase center and in the structures of many ribosomal proteins. Analysis of ribosomal features involved in dynamic aspects of protein biosynthesis that are partially or fully disordered in H50S revealed the conformations of intersubunit bridges in unbound subunits, suggesting how they may change upon subunit association and how movements of the L1-stalk may facilitate the exit of tRNA.

  12. Translational control of small heat shock genes in mesophilic and thermophilic cyanobacteria by RNA thermometers

    PubMed Central

    Cimdins, Annika; Klinkert, Birgit; Aschke-Sonnenborn, Ursula; Kaiser, Friederike M; Kortmann, Jens; Narberhaus, Franz

    2014-01-01

    Cyanobacteria constitute a heterogeneous phylum of oxygen-producing, photosynthetic prokaryotes. They are susceptible to various stress conditions like heat, salt, or light stress, all inducing the cyanobacterial heat shock response (HSR). Cyanobacterial small heat shock proteins (sHsps) are known to preserve thylakoid membrane integrity under stress conditions, thereby protecting the photosynthesis machinery. In Synechocystis sp PCC 6803, synthesis of the sHsp Hsp17 is regulated by an RNA thermometer (RNAT) in the 5?-untranslated region (5?-UTR) of the hsp17 mRNA. RNATs are direct temperature sensors that control expression of many bacterial heat shock and virulence genes. They hinder translation at low temperatures by base pairing, thus blocking ribosome access to the mRNA.   To explore the temperature range in which RNATs act, we studied various RNAT candidates upstream of sHsp genes from mesophilic and thermophilic cyanobacteria. The mesophilic cyanobacteria Anabaena variabilis and Nostoc sp chromosomally encode two sHsps each. Reporter gene studies suggested RNAT-mediated post-transcriptional regulation of shsp expression in both organisms. Detailed structural analysis of the two A. variabilis candidates revealed two novel RNAT types. The first, avashort, regulates translation primarily by masking of the AUG translational start codon. The second, featuring an extended initial hairpin, thus named avalong, presumably makes use of complex tertiary interaction. The 5?-UTR of the small heat shock gene hspA in the thermophile Thermosynechococcus elongatus is predicted to adopt an extended secondary structure. Structure probing revealed that the ribosome binding site was blocked at temperatures below 55 °C. The results of this study demonstrate that cyanobacteria commonly use RNATs to control expression of their small heat shock genes. PMID:24755616

  13. Modelling of the acid base properties of two thermophilic bacteria at different growth times

    NASA Astrophysics Data System (ADS)

    Heinrich, Hannah T. M.; Bremer, Phil J.; McQuillan, A. James; Daughney, Christopher J.

    2008-09-01

    Acid-base titrations and electrophoretic mobility measurements were conducted on the thermophilic bacteria Anoxybacillus flavithermus and Geobacillus stearothermophilus at two different growth times corresponding to exponential and stationary/death phase. The data showed significant differences between the two investigated growth times for both bacterial species. In stationary/death phase samples, cells were disrupted and their buffering capacity was lower than that of exponential phase cells. For G. stearothermophilus the electrophoretic mobility profiles changed dramatically. Chemical equilibrium models were developed to simultaneously describe the data from the titrations and the electrophoretic mobility measurements. A simple approach was developed to determine confidence intervals for the overall variance between the model and the experimental data, in order to identify statistically significant changes in model fit and thereby select the simplest model that was able to adequately describe each data set. Exponential phase cells of the investigated thermophiles had a higher total site concentration than the average found for mesophilic bacteria (based on a previously published generalised model for the acid-base behaviour of mesophiles), whereas the opposite was true for cells in stationary/death phase. The results of this study indicate that growth phase is an important parameter that can affect ion binding by bacteria, that growth phase should be considered when developing or employing chemical models for bacteria-bearing systems.

  14. Submerged filter biotreatment of hazardous leachate in aerobic, anaerobic, and anaerobic/aerobic systems

    SciTech Connect

    Smith, D.P.

    1995-12-31

    Aerobic, anaerobic and anaerobic/aerobic biotreatment of an industrial hazardous waste landfill leachate was evaluated in bench scale biofilm reactor systems operated under steady-and non-steady-state conditions. The leachate contained volatile and semi-volatile organics that exceeded the best-demonstrated-available-technology (BDAT) standard established for multi-source leachate wastewater under the Resources Conservation and Recovery Act (RCRA). The influent leachate stream was continuously applied to three parallel systems: (1) an upflow anaerobic filter followed by a submerged aerobic filter, both plastic packing, (2) an anaerobic granular activated carbon column, and (3) an upflow, plastic packed aerobic filter. All systems achieved steady-state COD removals of 66-82 percent. The sequential anaerobic/aerobic filter system was most resistant to hydraulic and organic shock loading, whereas the aerobic filter performance deteriorated significantly. Though transformations of specific chemical compounds were achieved in both anaerobic and aerobic treatment, the sequential anaerobic/aerobic system was cost effective for meeting BDAT standards for hazardous organics. 25 refs., 6 figs., 15 tabs.

  15. Accelerating Aerobic Sludge Granulation by Adding Dry Sewage Sludge Micropowder in Sequencing Batch Reactors

    PubMed Central

    Li, Jun; Liu, Jun; Wang, Danjun; Chen, Tao; Ma, Ting; Wang, Zhihong; Zhuo, Weilong

    2015-01-01

    Micropowder (20–250 µm) made from ground dry waste sludge from a municipal sewage treatment plant was added in a sequencing batch reactor (R2), which was fed by synthetic wastewater with acetate as carbon source. Compared with the traditional SBR (R1), aerobic sludge granulation time was shortened 15 days in R2. Furthermore, filamentous bacteria in bulking sludge were controlled to accelerate aerobic granulation and form large granules. Correspondingly, the SVI decreased from 225 mL/g to 37 mL/g. X-ray Fluorescence (XRF) analysis demonstrated that Al and Si from the micropowder were accumulated in granules. A mechanism hypotheses for the acceleration of aerobic granulation by adding dry sludge micropowder is proposed: added micropowder acts as nuclei to induce bacterial attachment; dissolved matters from the micropowder increase abruptly the organic load for starved sludge to control overgrown filamentous bacteria as a framework for aggregation; increased friction from the movement of micropowder forces the filaments which extend outwards to shrink for shaping granules. PMID:26308025

  16. Comparison of the SimPlate total plate count method with Petrifilm, Redigel, conventional pour-plate methods for enumerating aerobic microorganisms in foods.

    PubMed

    Beuchat, L R; Copeland, F; Curiale, M S; Danisavich, T; Gangar, V; King, B W; Lawlis, T L; Likin, R O; Okwusoa, J; Smith, C F; Townsend, D E

    1998-01-01

    The SimPlate Total Plate Count (TPC) method, developed by IDEXX Laboratories, Inc., is designed to determine the most probable number of aerobic microorganisms in foods. The 24-h test was compared to the conventional plate count agar (PCA) method, the Petrifilm Aerobic Count plates, and the Redigel Total Count procedure for enumerating microflora in 751 food samples. Results using the SimPlate TPC method were highly correlated (r > or = 0.96) with results from other test methods. Slopes (0.96-0.97) were not significantly different from 1, and y intercepts (-0.03-0.08) were not different from O. The SimPlate has a high counting range (> 1600 most probable number per single dilution), thus requiring fewer dilutions of samples compared to other methods evaluated. Some foods, e.g., raw liver, wheat flour, and nuts, contain enzymes that gave false-positive reactions on SimPlates. Overall, however, the SimPlate TPC method is a suitable alternative to conventional PCA, Petrifilm, and Redigel methods for estimating populations of mesophilic aerobic microorganisms in a wide range of foods. PMID:9708246

  17. Back To Bacteria.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    1997-01-01

    Explores new research about bacteria. Discusses bacterial genomes, archaea, unusual environments, evolution, pathogens, bacterial movement, biofilms, bacteria in the body, and a bacterial obsession. Contains 29 references. (JRH)

  18. Comparative study of normal and sensitive skin aerobic bacterial populations

    PubMed Central

    Hillion, Mélanie; Mijouin, Lily; Jaouen, Thomas; Barreau, Magalie; Meunier, Pauline; Lefeuvre, Luc; Lati, Elian; Chevalier, Sylvie; Feuilloley, Marc G J

    2013-01-01

    The purpose of this study was to investigate if the sensitive skin syndrome, a frequent skin disorder characterized by abnormal painful reactions to environmental factors in the absence of visible inflammatory response, could be linked to a modification in the skin bacterial population. A total of 1706 bacterial isolates was collected at the levels of the forehead, cheekbone, inner elbow, and lower area of the scapula on the skin of normal and sensitive skin syndrome-suffering volunteers of both sexes and of different ages. Among these isolates, 21 strains were randomly selected to validate in a first step the Matrix-Assisted Laser Desorption/Ionization (MALDI)-Biotyper process as an efficient identification tool at the group and genus levels, by comparison to API® strips and 16S ribosomal RNA gene sequencing identification techniques. In a second step, identification of the skin microbiota isolates by the MALDI-Biotyper tool allowed to pinpoint some differences in terms of bacterial diversity with regard to the collection area, and the volunteer's age and gender. Finally, comparison of the skin microbiota from normal and sensitive skin syndrome-suffering volunteers pointed out gender-related variations but no detectable correlation between a phylum, a genus or a dominant bacterial species and the sensitive skin phenotype. This study reveals that there is no dysbiosis of aerobic cultivable bacteria associated with the sensitive skin syndrome and further demonstrates that the MALDI-Biotyper is a powerful technique that can be efficiently employed to the study of cultivable human skin bacteria. To our knowledge, this is the first study focusing on bacteria in the sensitive skin syndrome. These results are of potential importance for pharmaceutical and cosmetic industries, which are looking for new strategies to treat this multiparametric disorder. PMID:24151137

  19. The inhibition of Clostridium botulinum type C by other bacteria in wetland sediments

    USGS Publications Warehouse

    Sandler, Renee J.; Rocke, Tonie E.; Yuill, Thomas M.

    1998-01-01

    Bacteria with inhibitory activity against Clostridium botulinum type C were isolated from 32% of sediment samples (n = 1600) collected from 10 marshes in a northern California wetland over a 12 mo period. Aerobic and anaerobic bacteria with inhibitory activity were isolated from 12% and 23% of the samples, respectively. Bacteria with inhibitory activity were isolated from all 10 study sites and throughout the year. This study demonstrates that bacteria with inhibitory activity against C. botulinum type C occur naturally in wetland sediments.

  20. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    NASA Astrophysics Data System (ADS)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    Life evolved and flourished in the absence of molecular oxygen (O2). As the O2 content of the atmosphere rose to the present level of 21% beginning about two billion years ago, anaerobic metabolism was gradually supplanted by aerobic metabolism. Anaerobic environments have persisted on Earth despite the transformation to an oxidized state because of the combined influence of water and organic matter. Molecular oxygen diffuses about 104 times more slowly through water than air, and organic matter supports a large biotic O2 demand that consumes the supply faster than it is replaced by diffusion. Such conditions exist in wetlands, rivers, estuaries, coastal marine sediments, aquifers, anoxic water columns, sewage digesters, landfills, the intestinal tracts of animals, and the rumen of herbivores. Anaerobic microsites are also embedded in oxic environments such as upland soils and marine water columns. Appreciable rates of aerobic respiration are restricted to areas that are in direct contact with air or those inhabited by organisms that produce O2.Rising atmospheric O2 reduced the global area of anaerobic habitat, but enhanced the overall rate of anaerobic metabolism (at least on an area basis) by increasing the supply of electron donors and acceptors. Organic carbon production increased dramatically, as did oxidized forms of nitrogen, manganese, iron, sulfur, and many other elements. In contemporary anaerobic ecosystems, nearly all of the reducing power is derived from photosynthesis, and most of it eventually returns to O2, the most electronegative electron acceptor that is abundant. This photosynthetically driven redox gradient has been thoroughly exploited by aerobic and anaerobic microorganisms for metabolism. The same is true of hydrothermal vents (Tunnicliffe, 1992) and some deep subsurface environments ( Chapelle et al., 2002), where thermal energy is the ultimate source of the reducing power.Although anaerobic habitats are currently a small fraction of Earth's surface area, they have a profound influence on the biogeochemistry of the planet. This is evident from the observation that the O2 and CH4 content of Earth's atmosphere are in extreme disequilibrium (Sagan et al., 1993). The combination of high aerobic primary production and anoxic sediments provided the large deposits of fossil fuels that have become vital and contentious sources of energy for modern industrialized societies. Anaerobic metabolism is responsible for the abundance of N2 in the atmosphere; otherwise N2-fixing bacteria would have consumed most of the N2 pool long ago (Schlesinger, 1997). Anaerobic microorganisms are common symbionts of termites, cattle, and many other animals, where they aid digestion. Nutrient and pollutant chemistry are strongly modified by the reduced conditions that prevail in wetland and aquatic ecosystems.This review of anaerobic metabolism emphasizes aerobic oxidation, because the two processes cannot be separated in a complete treatment of the topic. It is process oriented and highlights the fascinating microorganisms that mediate anaerobic biogeochemistry. We begin this review with a brief discussion of CO2 assimilation by autotrophs, the source of most of the reducing power on Earth, and then consider the biological processes that harness this potential energy. Energy liberation begins with the decomposition of organic macromolecules to relatively simple compounds, which are simplified further by fermentation. Methanogenesis is considered next because CH4 is a product of acetate fermentation, and thus completes the catabolism of organic matter, particularly in the absence of inorganic electron acceptors. Finally, the organisms that use nitrogen, manganese, iron, and sulfur for terminal electron acceptors are considered in order of decreasing free-energy yield of the reactions.

  1. Influence of Light on Carbon Utilization in Aerobic Anoxygenic Phototrophs

    PubMed Central

    Hauruseu, Dzmitry

    2012-01-01

    Aerobic anoxygenic phototrophs contain photosynthetic reaction centers composed of bacteriochlorophyll. These organisms are photoheterotrophs, as they require organic carbon substrates for their growth whereas light-derived energy has only an auxiliary function. To establish the contribution of light energy to their metabolism, we grew the phototrophic strain Erythrobacter sp. NAP1 in a carbon-limited chemostat regimen on defined carbon sources (glutamate, pyruvate, acetate, and glucose) under conditions of different light intensities. When grown in a light-dark cycle, these bacteria accumulated 25% to 110% more biomass in terms of carbon than cultures grown in the dark. Cultures grown on glutamate accumulated the most biomass at moderate light intensities of 50 to 150 ?mol m?2 s?1 but were inhibited at higher light intensities. In the case of pyruvate, we did not find any inhibition of growth by high irradiance. The extent of anaplerotic carbon fixation was detemined by radioactive bicarbonate incorporation assays. While the carboxylation activity provided 4% to 11% of the cellular carbon in the pyruvate-grown culture, in the glutamate-grown cells it provided only approximately 1% of the carbon. Additionally, we tested the effect of light on respiration and photosynthetic electron flow. With increasing light intensity, respiration decreased to approximately 25% of its dark value and was replaced by photophosphorylation. The additional energy from light allows the aerobic anoxygenic phototrophs to accumulate the supplied organic carbon which would otherwise be respired. The higher efficiency of organic carbon utilization may provide an important competitive advantage during growth under carbon-limited conditions. PMID:22885759

  2. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    EPA Science Inventory

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  3. On-Site Wastewater Treatment Systems: Aerobic Treatment Unit (Spanish) 

    E-print Network

    Lesikar, Bruce J.; Enciso, Juan

    2000-08-29

    Aerobic units treat wastewater using the same process, only scaled down, as municipal wastewater treatment systems. This publication explains how aerobic units work, what their design requirements are, and how to maintain them....

  4. Without Salt, the ‘Thermophilic’ Protein Mth10b Is Just Mesophilic

    PubMed Central

    Zhang, Nan; Pan, Xian-Ming; Ge, Meng

    2012-01-01

    Most proteins from thermophiles or hyperthermophiles are intrinsically thermostable. However, though Methanobacterium thermoautotrophicum ?H is a thermophilic archaeon with an optimal growth temperature of 65°C, Mth10b, an atypical member the Sac10b protein family from M. thermoautotrophicum ?H, seems not intrinsically thermostable. In this work, to clarify the molecular mechanism of Mth10b remaining stable under its physiological conditions, the thermodynamic properties of Mth10b were studied through equilibrium unfolding experiments performed at pH 7.0 monitored by circular dichroism (CD) spectra in detail. Our work demonstrated that Mth10b is not intrinsically thermostable and that due to the masking effect upon the large numbers of destabilizing electrostatic repulsions resulting from the extremely uneven distribution of charged residues over the surface of Mth10b, salt can contribute to the thermostability of Mth10b greatly. Considering that the intracellular salt concentration is high to 0.7 M, we concluded that salt is the key extrinsic factor to Mth10b remaining stable under its physiological conditions. In other word, without salt, ‘thermophilic’ protein Mth10b is just a mesophilic one. PMID:23300880

  5. Mesophilic anaerobic co-digestion of cattle manure and corn stover with biological and chemical pretreatment.

    PubMed

    Wei, Yufang; Li, Xiujin; Yu, Liang; Zou, Dexun; Yuan, Hairong

    2015-12-01

    Biological and chemical pretreatment methods using liquid fraction of digestate (LFD), ammonia solution (AS), and NaOH were compared in the process of mesophilic anaerobic co-digestion of cattle manure and corn stover. The results showed that LFD pretreatment could achieve the same effect as the chemical pretreatment (AS, NaOH) at the performance of anaerobic digestion (AD). Compared with the untreated corn stover, the cumulative biomethane production (CBP) and the volatile solid (VS) removal rate of three pretreatment methods were increased by 25.40-30.12% and 14.48-16.84%, respectively, in the co-digestion of cattle manure and corn stover. T80 was 20-37.14% shorter than that of the control test (35±1days). LFD pretreatment not only achieved the same effect as chemical pretreatment, but also reduced T80 and improved buffer capacity of anaerobic digestion system. Therefore, this study provides meaningful insight for exploring efficient pretreatment strategy to stabilize and enhance AD performance for practical application. PMID:26409855

  6. Crystal structures of virus-like photosystem I complexes from the mesophilic cyanobacterium Synechocystis PCC 6803

    PubMed Central

    Mazor, Yuval; Nataf, Daniel; Toporik, Hila; Nelson, Nathan

    2014-01-01

    Oxygenic photosynthesis supports virtually all life forms on earth. Light energy is converted by two photosystems—photosystem I (PSI) and photosystem II (PSII). Globally, nearly 50% of photosynthesis takes place in the Ocean, where single cell cyanobacteria and algae reside together with their viruses. An operon encoding PSI was identified in cyanobacterial marine viruses. We generated a PSI that mimics the salient features of the viral complex, named PSIPsaJF. PSIPsaJF is promiscuous for its electron donors and can accept electrons from respiratory cytochromes. We solved the structure of PSIPsaJF and a monomeric PSI, with subunit composition similar to the viral PSI, providing for the first time a detailed description of the reaction center and antenna system from mesophilic cyanobacteria, including red chlorophylls and cofactors of the electron transport chain. Our finding extends the understanding of PSI structure, function and evolution and suggests a unique function for the viral PSI. DOI: http://dx.doi.org/10.7554/eLife.01496.001 PMID:24473073

  7. Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion.

    PubMed

    Mendes, Carlos; Esquerre, Karla; Matos Queiroz, Luciano

    2015-01-01

    Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35kg/m(3) day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge. PMID:25458762

  8. A comparative molecular dynamics study of thermophilic and mesophilic ?-fructosidase enzymes.

    PubMed

    Mazola, Yuliet; Guirola, Osmany; Palomares, Sucel; Chinea, Glay; Menéndez, Carmen; Hernández, Lázaro; Musacchio, Alexis

    2015-09-01

    Arabidopsis thaliana cell wall invertase 1 (AtcwINV1) and Thermotoga maritima ?-fructosidase (BfrA) are among the best structurally studied members of the glycoside hydrolase family 32. Both enzymes hydrolyze sucrose as the main substrate but differ strongly in their thermal stability. Mesophilic AtcwINV1 and thermophilic BfrA have divergent sequence similarities in the N-terminal five bladed ?-propeller catalytic domain (31 %) and the C-terminal ?-sandwich domain (15 %) of unknown function. The two enzymes were subjected to 200 ns molecular dynamics simulations at 300 K (27 °C) and 353 K (80 °C). Regular secondary structure regions, but not loops, in AtcwINV1 and BfrA showed no significant fluctuation differences at both temperatures. BfrA was more rigid than AtcwINV1 at 300 K. The simulation at 353 K did not alter the structural stability of BfrA, but did increase the overall flexibility of AtcwINV1 exhibiting the most fluctuating regions in the ?-propeller domain. The simulated heat treatment also increased the gyration radius and hydrophobic solvent accessible surface area of the plant enzyme, consistent with the initial steps of an unfolding process. The preservation of the conformational rigidity of BfrA at 353 K is linked to the shorter size of the protein loops. Shortening of BfrA loops appears to be a key mechanism for thermostability. PMID:26267297

  9. Enhanced mesophilic anaerobic digestion of food waste by thermal pretreatment: Substrate versus digestate heating.

    PubMed

    Ariunbaatar, Javkhlan; Panico, Antonio; Yeh, Daniel H; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni

    2015-12-01

    Food waste (FW) represents a source of high potential renewable energy if properly treated with anaerobic digestion (AD). Pretreating the substrates could yield a higher biomethane production in a shorter time. In this study, the effects of thermal (heating the FW in a separate chamber) and thermophilic (heating the full reactor content containing both FW and inoculum) pretreatments at 50, 60, 70 and 80°C prior to mesophilic AD were studied through a series of batch experiments. Pretreatments at a lower temperature (50°C) and a shorter time (<12h) had a positive effect on the AD process. The highest enhancement of the biomethane production with an increase by 44-46% was achieved with a thermophilic pretreatment at 50°C for 6-12h or a thermal pretreatment at 80°C for 1.5h. Thermophilic pretreatments at higher temperatures (>55°C) and longer operating times (>12h) yielded higher soluble chemical oxygen demand (CODs), but had a negative effect on the methanogenic activity. The thermal pretreatments at the same conditions resulted in a lower solubilization of COD. Based on net energy calculations, the enhanced biomethane production is sufficient to heat up the FW for the thermal, but not for the thermophilic pretreatment. PMID:26272711

  10. Bioleaching of multiple heavy metals from contaminated sediment by mesophile consortium.

    PubMed

    Gan, Min; Zhou, Shuang; Li, Mingming; Zhu, Jianyu; Liu, Xinxing; Chai, Liyuan

    2015-04-01

    A defined mesophile consortium including Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirilum ferriphilum was applied in bioleaching sediments contaminated with multiple heavy metals. Flask experiments showed that sulfur favored the acidification in the early stage while pyrite led to a great acidification potential in the later stage. An equal sulfur/pyrite ratio got the best acidification effect. Substrate utilization started with sulfur in the early stage, and then the pH decline and the community shift give rise to the utilization of pyrite. Solubilization efficiency of Zn, Cu, Mn, and Cd reached 96.1, 93.3, 92.13, and 87.65%, respectively. Bioleaching efficiency of other elements (As, Hg, Pb) was not more than 30%. Heavy metal solubilization was highly negatively correlated with pH variation. Logistic models were well fitted with the solubilization efficiency, which can be used to predict the bioleaching process. The dominant species in the early stage of bioleaching were A. ferrooxidans and A. thiooxidans, and the abundance of L. ferriphilum increased together with pyrite utilization and pH decline. PMID:25384695

  11. An integrated approach for thermal stabilization of a mesophilic adenylate kinase.

    PubMed

    Moon, Sojin; Jung, Du-kyo; Phillips, George N; Bae, Euiyoung

    2014-09-01

    Thermally stable proteins are desirable for research and industrial purposes, but redesigning proteins for higher thermal stability can be challenging. A number of different techniques have been used to improve the thermal stability of proteins, but the extents of stability enhancement were sometimes unpredictable and not significant. Here, we systematically tested the effects of multiple stabilization techniques including a bioinformatic method and structure-guided mutagenesis on a single protein, thereby providing an integrated approach to protein thermal stabilization. Using a mesophilic adenylate kinase (AK) as a model, we identified stabilizing mutations based on various stabilization techniques, and generated a series of AK variants by introducing mutations both individually and collectively. The redesigned proteins displayed a range of increased thermal stabilities, the most stable of which was comparable to a naturally evolved thermophilic homologue with more than a 25° increase in its thermal denaturation midpoint. We also solved crystal structures of three representative variants including the most stable variant, to confirm the structural basis for their increased stabilities. These results provide a unique opportunity for systematically analyzing the effectiveness and additivity of various stabilization mechanisms, and they represent a useful approach for improving protein stability by integrating the reduction of local structural entropy and the optimization of global noncovalent interactions such as hydrophobic contact and ion pairs. PMID:24615904

  12. Improvement of mesophilic anaerobic co-digestion of agri-food waste by addition of glycerol.

    PubMed

    Serrano, Antonio; Siles, Jose A; Chica, Arturo F; Martin, M Angeles

    2014-07-01

    Anaerobic co-digestion is a promising alternative to manage agri-food waste rather than landfilling, composting or incineration. But improvement of methane yield and biodegradability is often required to optimize its economic viability. Biomethanization of agri-food solid waste presents the disadvantage of a slow hydrolytic phase, which might be enhanced by adding a readily digestible substrate such as glycerol. In this study, strawberry extrudate, fish waste and crude glycerol derived from biodiesel manufacturing are mixed at a proportion of 54:5:41, in VS (VS, total volatile solids), respectively. The mesophilic anaerobic co-digestion at lab-scale of the mixture was stable at loads lower than 1.85 g VS/L, reaching a methane yield coefficient of 308 L CH4/kg VS (0 °C, 1 atm) and a biodegradability of 96.7%, in VS. Moreover, the treatment capacity of strawberry and fish waste was increased 16% at adding the crude glycerol. An economic assessment was also carried out in order to evaluate the applicability of the proposed process. Even in a pessimistic scenario, the net balance was found to be positive. The glycerol adding implied a net saving in a range from 25.5 to 42.1 €/t if compared to landfill disposal. PMID:24726968

  13. Isolation and Characterization of Methanomicrobium paynteri sp. nov., a Mesophilic Methanogen Isolated from Marine Sediments †

    PubMed Central

    Rivard, Christopher J.; Henson, J. Michael; Thomas, Michael V.; Smith, Paul H.

    1983-01-01

    A new mesophilic methanogenic bacterial species isolated from marine sediments collected in the Cayman Islands is described. Cells are small rods occuring singly without filaments, are not motile, and do not possess flagella. Colonies are semitransparent and off-white in color. After 2 weeks of incubation at 37°C colonies are 1 to 2 mm in size, circular, and have entire edges. Only hydrogen-carbon dioxide is a substrate for growth and methane formation. Cells can tolerate a variety of organic secondary buffers (bicarbonate-CO2 being the primary buffer). Cells do not require yeast extract or Trypticase, but do require acetate, for growth. The optimum growth temperature is 40°C. The optimum sodium concentration is 0.15 M. The optimum pH for growth is 7.0. The minimum generation time is 4.8 h. The DNA base composition is 44.9 mol% guanine plus cytosine. The name Methanomicrobium paynteri is proposed in honor of M. J. B. Paynter. The type strain is G-2000 (=ATCC 33997, =DSM 2545). Images PMID:16346371

  14. A micro-aerobic hydrolysis process for sludge in situ reduction: performance and microbial community structure.

    PubMed

    Zhou, Zhen; Qiao, Weimin; Xing, Can; Shen, Xuelian; Hu, Dalong; Wang, Luochun

    2014-12-01

    A sludge process reduction activated sludge (SPRAS) system by inserting a sludge process reduction (SPR) module, composed of a micro-aerobic tank and a settler, before activated sludge process was operated for sludge in situ reduction. The average removal efficiencies of COD and ammonium nitrogen were 86.6% and 87.9%, respectively. Compared to anoxic/aerobic (AO) process, SPRAS process reduced sludge production by 57.9% with observed sludge yield of 0.076 gVSS/gCOD. Pyrosequencing analyses revealed that the relative abundance and stability of microbial communities in SPRAS system were higher than AO system. Fermentative acidogenic classes Anaerolineae, Actinobacteria, Cytophagia and Caldilineae were enriched in the SPR module and responsible for sludge reduction. Specific comparison down to the genus level identified the enrichment of oxyanion-reducing bacteria (Sulfuritalea; Azospira; Ramlibacter), fermentative acidogenic bacteria (Propionivibrio; Opitutus; Caldilinea), slow growers (Ramlibacter) and predatory bacteria (Myxobacteria) in SPRAS system. Nitrifiers were also more abundant in SPRAS system than AO system. PMID:25311187

  15. Liver abscesses in dromedary camels: Pathological characteristics and aerobic bacterial aetiology

    PubMed Central

    Aljameel, M.A.; Halima, M.O.; ElTigani-Asil, A.E.; Abdalla, A.S.; Abdellatif, M.M.

    2014-01-01

    The study was carried out at Nyala abattoirs, South Darfur State, Sudan during a period from 2009 to 2011. Slaughtered camels (822) were examined for pathological changes of liver abscesses and identification of the involved aerobic bacteria. Grossly, a total of 111 (13.5%) liver abscesses were recorded in different camel ages; 90 (81.1%) were less than seven years old and 21 (18.9%) were more than seven years old. Histopathology of sectioned tissues revealed necrotic abscesses with infiltration of inflammatory cells, hydropic degeneration with swelling of hepatocytes comprising the sinusoid and different size of vacuoles in the hepatic cells. Proliferation of bile ducts with fibrous tissue and infiltration of inflammatory cells was also recorded. Investigation of bacteria revealed 90 aerobic isolates; they were identified to 52 (57.8%) gram positive cocci, 20 (22.2%) gram positive rods and 18 (20.0%) gram negative rods. Staphylococcus spp. (41.1%), Corynebacterium spp. (17.9%) and Streptococcus spp. (13.3%) were the most frequently identified bacteria involved in liver abscesses of camels in the region. Further studies are required to assess the pathogenicity of bacterial isolates from camel livers. This is particularly important from a public health perspective, since some people of Sudan are known to consume raw camel liver.

  16. Do homologous thermophilic-mesophilic proteins exhibit similar structures and dynamics at optimal growth temperatures? A molecular dynamics simulation study.

    PubMed

    Basu, Sohini; Sen, Srikanta

    2013-02-25

    Structure and dynamics both are known to be important for the activity of a protein. A fundamental question is whether a thermophilic protein and its mesophilic homologue exhibit similar dynamics at their respective optimal growth temperatures. We have addressed this question by performing molecular dynamics (MD) simulations of a natural mesophilic-thermophilic homologue pair at their respective optimal growth temperatures to compare their structural, dynamical, and solvent properties. The MD simulations were done in explicit aqueous solvent under periodic boundary and constant pressure and temperature (CPT) conditions and continued for 10.0 ns using the same protocol for the two proteins, excepting the temperatures. The trajectories were analyzed to compare the properties of the two proteins. Results indicated that the dynamical behaviors of the two proteins at the respective optimal growth temperatures were remarkably similar. For the common residues in the thermophilic protein, the rms fluctuations have a general trend to be slightly higher compared to that in the mesophilic counterpart. Lindemann parameter values indicated that only a few residues exhibited solid-like dynamics while the protein as a whole appeared as a molten globule in each case. Interestingly, the water-water interaction was found to be strikingly similar in spite of the difference in temperatures while, the protein-water interaction was significantly different in the two simulations. PMID:23267663

  17. Effect of ultrasound pretreatment in mesophilic and thermophilic anaerobic digestion with emphasis on naphthalene and pyrene removal.

    PubMed

    Benabdallah El-Hadj, T; Dosta, J; Márquez-Serrano, R; Mata-Alvarez, J

    2007-01-01

    In many anaerobic digestion processes for the treatment of the sludge produced in wastewater treatment plants, the hydrolysis of the organic matter has been identified as the rate limiting step. This study is focused on the effect of ultrasonic pretreatment of raw sewage sludge before being fed to the mesophilic and the thermophilic anaerobic digestion. From particle size reduction, COD disintegration degree and biodegradability test, 11,000kJ/kg TS was estimated as the optimal specific energy in ultrasonic pretreatment. Moreover, the use of pretreated sludge improved significantly the COD removal efficiency and biogas production in lab-scale anaerobic digesters when compared with the performance without pretreatment, specially under mesophilic conditions. During ultrasonic pretreatment, the diffusion of polycyclic aromatic hydrocarbons (PAH) compounds to the aqueous phase was stated by a reduction in the pretreated sludge micropollutants content. With sonication, naphthalene was better removed than without this pretreatment, particularly in the mesophilic digester. However, pyrene removal remained at same efficiency level with and without ultrasonic pretreatment. PMID:17113620

  18. Mesophilic and Thermophilic Conditions Select for Unique but Highly Parallel Microbial Communities to Perform Carboxylate Platform Biomass Conversion

    PubMed Central

    Hollister, Emily B.; Forrest, Andrea K.; Wilkinson, Heather H.; Ebbole, Daniel J.; Tringe, Susannah G.; Malfatti, Stephanie A.; Holtzapple, Mark T.; Gentry, Terry J.

    2012-01-01

    The carboxylate platform is a flexible, cost-effective means of converting lignocellulosic materials into chemicals and liquid fuels. Although the platform's chemistry and engineering are well studied, relatively little is known about the mixed microbial communities underlying its conversion processes. In this study, we examined the metagenomes of two actively fermenting platform communities incubated under contrasting temperature conditions (mesophilic 40°C; thermophilic 55°C), but utilizing the same inoculum and lignocellulosic feedstock. Community composition segregated by temperature. The thermophilic community harbored genes affiliated with Clostridia, Bacilli, and a Thermoanaerobacterium sp, whereas the mesophilic community metagenome was composed of genes affiliated with other Clostridia and Bacilli, Bacteriodia, ?-Proteobacteria, and Actinobacteria. Although both communities were able to metabolize cellulosic materials and shared many core functions, significant differences were detected with respect to the abundances of multiple Pfams, COGs, and enzyme families. The mesophilic metagenome was enriched in genes related to the degradation of arabinose and other hemicellulose-derived oligosaccharides, and the production of valerate and caproate. In contrast, the thermophilic community was enriched in genes related to the uptake of cellobiose and the transfer of genetic material. Functions assigned to taxonomic bins indicated that multiple community members at either temperature had the potential to degrade cellulose, cellobiose, or xylose and produce acetate, ethanol, and propionate. The results of this study suggest that both metabolic flexibility and functional redundancy contribute to the platform's ability to process lignocellulosic substrates and are likely to provide a degree of stability to the platform's fermentation processes. PMID:22761870

  19. Effectiveness and limitations of local structural entropy optimization in the thermal stabilization of mesophilic and thermophilic adenylate kinases.

    PubMed

    Moon, Sojin; Bannen, Ryan M; Rutkoski, Thomas J; Phillips, George N; Bae, Euiyoung

    2014-10-01

    Local structural entropy (LSE) is a descriptor for the extent of conformational heterogeneity in short protein sequences that is computed from structural information derived from the Protein Data Bank. Reducing the LSE of a protein sequence by introducing amino acid mutations can result in fewer conformational states and thus a more stable structure, indicating that LSE optimization can be used as a protein stabilization method. Here, we describe a series of LSE optimization experiments designed to stabilize mesophilic and thermophilic adenylate kinases (AKs) and report crystal structures of LSE-optimized AK variants. In the mesophilic AK, thermal stabilization by LSE reduction was effective but limited. Structural analyses of the LSE-optimized mesophilic AK variants revealed a strong correlation between LSE and the apolar buried surface area. Additional mutations designed to introduce noncovalent interactions between distant regions of the polypeptide resulted in further stabilization. Unexpectedly, optimizing the LSE of the thermophilic AK resulted in a decrease in thermal stability. This destabilization was reduced when charged residues were excluded from the possible substitutions during LSE optimization. These observations suggest that stabilization by LSE reduction may result from the optimization of local hydrophobic contacts. The limitations of this process are likely due to ignorance of other interactions that bridge distant regions in a given amino acid sequence. Our results illustrate the effectiveness and limitations of LSE optimization as a protein stabilization strategy and highlight the importance and complementarity of local conformational stability and global interactions in protein thermal stability. PMID:24931334

  20. Interactive effects of hypobaria, low temperature, and CO 2 atmospheres inhibit the growth of mesophilic Bacillus spp. under simulated martian conditions

    NASA Astrophysics Data System (ADS)

    Schuerger, Andrew C.; Nicholson, Wayne L.

    2006-11-01

    Robotic spacecraft are launched with finite levels of terrestrial microorganisms that are similar to the microbial communities within facilities in which spacecraft are assembled. In particular, spores of mesophilic aerobic Bacillus species are common spacecraft contaminants considered most likely to survive interplanetary transfer to Mars. During the cruise phase to Mars, and then again during surface operations, microbial bioloads are exposed to a diversity of biocidal factors that are likely to render the microbial species either dead or significantly inhibited from active metabolic activity and replication. We report here, for the first time, that interactive effects of low pressure, low temperature, and high CO 2 atmospheres approaching conditions likely to be encountered on the martian surface strongly inhibit the growth and replication of seven common Bacillus spp. isolated from spacecraft. Tests were conducted within a small glass bell-jar system maintained in a low-temperature microbial incubator. Atmospheric pressures were controlled at 1013 (Earth-normal), 100, 50, 35, 25, or 15 mb, and temperatures were maintained at 30, 20, 15, 10, or 5 °C. Experiments were carried out for 48 h or 7 days under either Earth-normal O 2/N 2 or pure CO 2 atmospheres. Results indicated that low pressure, low temperature, and high CO 2 atmospheres, applied separately or in combination, were capable of inhibiting the growth and replication of B. pumilus SAFR-032, B. pumilus FO-36B, B. subtilis HA-101, B. subtilis 42HS-1, B. megaterium KL-197, B. licheniformis KL-196, and B. nealsonii FO-092 under simulated martian conditions. Endospores of all seven Bacillus spp. strains failed to germinate and grow at 25 mb at 30 °C. Although, vegetative cells of these strains exhibited a slightly greater ability to replicate at lower pressures than did endospores, vegetative cells of these species failed to grow at pressures below 25 mb. Interactive effects of these environmental parameters acted to generally increase the inhibitory nature of the low-pressure conditions on growth and replication of the seven Bacillus spp. tested.

  1. Bioelectricity Aware of bacteria

    E-print Network

    Lovley, Derek

    Bioelectricity Aware of bacteria Bacteria of the genus Geobacter carry out anaerobic respiration the mechanism that makes these bacteria conductors of electricity. Researchers have studied this for a population of G. sulfurreducens, endowed with bacteria nanometric filaments (pili) that enable them

  2. Enrichment and Characterization of an Autotrophic Ammonia-Oxidizing Archaeon of Mesophilic Crenarchaeal Group I.1a from an Agricultural Soil?†

    PubMed Central

    Jung, Man-Young; Park, Soo-Je; Min, Deullae; Kim, Jin-Seog; Rijpstra, W. Irene C.; Sinninghe Damsté, Jaap S.; Kim, Geun-Joong; Madsen, Eugene L.; Rhee, Sung-Keun

    2011-01-01

    Soil nitrification is an important process for agricultural productivity and environmental pollution. Though one cultivated representative of ammonia-oxidizing Archaea from soil has been described, additional representatives warrant characterization. We describe an ammonia-oxidizing archaeon (strain MY1) in a highly enriched culture derived from agricultural soil. Fluorescence in situ hybridization microscopy showed that, after 2 years of enrichment, the culture was composed of >90% archaeal cells. Clone libraries of both 16S rRNA and archaeal amoA genes featured a single sequence each. No bacterial amoA genes could be detected by PCR. A [13C]bicarbonate assimilation assay showed stoichiometric incorporation of 13C into Archaea-specific glycerol dialkyl glycerol tetraethers. Strain MY1 falls phylogenetically within crenarchaeal group I.1a; sequence comparisons to “Candidatus Nitrosopumilus maritimus” revealed 96.9% 16S rRNA and 89.2% amoA gene similarities. Completed growth assays showed strain MY1 to be chemoautotrophic, mesophilic (optimum at 25°C), neutrophilic (optimum at pH 6.5 to 7.0), and nonhalophilic (optimum at 0.2 to 0.4% salinity). Kinetic respirometry assays showed that strain MY1's affinities for ammonia and oxygen were much higher than those of ammonia-oxidizing bacteria (AOB). The yield of the greenhouse gas N2O in the strain MY1 culture was lower but comparable to that of soil AOB. We propose that this new soil ammonia-oxidizing archaeon be designated “Candidatus Nitrosoarchaeum koreensis.” PMID:22003023

  3. Ventilation and Speech Characteristics during Submaximal Aerobic Exercise

    ERIC Educational Resources Information Center

    Baker, Susan E.; Hipp, Jenny; Alessio, Helaine

    2008-01-01

    Purpose: This study examined alterations in ventilation and speech characteristics as well as perceived dyspnea during submaximal aerobic exercise tasks. Method: Twelve healthy participants completed aerobic exercise-only and simultaneous speaking and aerobic exercise tasks at 50% and 75% of their maximum oxygen consumption (VO[subscript 2] max).…

  4. Formation of aerobic granular sludge biofilms for sustainable wastewater treatment

    E-print Network

    Lenstra, Arjen K.

    ENAC/ Formation of aerobic granular sludge biofilms for sustainable wastewater treatment David G to aerobic granular microbial biofilms (Confocal laser scanning microscopy analysis) Floc viscous bulking) Exopolysaccharide-producing Zoogloea spp. form the early-stage aerobic granular biofilms, and then decline

  5. AEROBIC ENERGETICS OF SURFACE SWIMMING IN THE MUSKRAT ONDATRA ZIBETHICUS'

    E-print Network

    Fish, Frank

    , AEROBIC ENERGETICS OF SURFACE SWIMMING IN THE MUSKRAT ONDATRA ZIBETHICUS' F U N K E. FISHZ of the aerobic power input. The metabolic rate (Va2)of swimming muskrats at a water temperature of 25 C was found metabolism to the aerobic metabolism and onset of fatigue at velocities above 0.6 m/s due to high drag

  6. Kinetic and Inhibition Studies for the Aerobic Cometabolism of

    E-print Network

    Semprini, Lewis

    Kinetic and Inhibition Studies for the Aerobic Cometabolism of 1,1,1-Trichloroethane, 1 performed for the aerobic cometabolism of 1,1,1- trichloroethane (1,1,1-TCA), 1,1-dichloroethylene (1,1- DCE­508, 2002. Keywords: aerobic cometabolism of CAH mixtures; com- petitive and mixed inhibition; direct linear

  7. Adolescents' Interest and Performances in Aerobic Fitness Testing

    ERIC Educational Resources Information Center

    Zhu, Xihe; Chen, Senlin; Parrott, James

    2014-01-01

    This study examined adolescents' interest in aerobic fitness testing and its relation to the test performances. Adolescents (N = 356) from three middle schools participated in the study. The participants took two aerobic fitness tests: the Progressive Aerobic Cardiovascular Endurance Run (PACER) and One-Mile Run (1MR) with a two-day interval,…

  8. Recent Developments in Aerobic Stoltz Group Literature Talk

    E-print Network

    Stoltz, Brian M.

    Recent Developments in Aerobic Oxidation Stoltz Group Literature Talk Monday, August 21, 2006 Brinton Seashore-Ludlow #12;OH O Enantioselective Wacker Cyclization N R N R Aerobic Oxidative Annulation of Indoles Aerobic Oxidative Kinetic Resolution of Secondary Alcohols R OH R' R OH R' R O R' Ferreira, E. M

  9. Utilization of Fluoroethene as a Surrogate for Aerobic Vinyl Chloride

    E-print Network

    Semprini, Lewis

    Utilization of Fluoroethene as a Surrogate for Aerobic Vinyl Chloride Transformation A N N E E) is a stable molecule in aqueous solution and its aerobic transformation potentially yields F-. This work evaluated if FE is a suitable surrogate for monitoring aerobic vinyl chloride (VC) utilization

  10. Comment on "Growing Rice Aerobically Markedly Decreases Arsenic Accumulation"

    E-print Network

    van Geen, Alexander

    Comment on "Growing Rice Aerobically Markedly Decreases Arsenic Accumulation" In a detailed study is transferred to the rice grain and eventually eaten. We do not dispute the main finding that aerobic (1, 9); there may be an arsenic threshold that triggers methylation that is not reached in aerobic

  11. Accelerated Longitudinal Decline of Aerobic Capacity in Healthy Older Adults

    E-print Network

    Morrell, Christopher H.

    Accelerated Longitudinal Decline of Aerobic Capacity in Healthy Older Adults Jerome L. Fleg, MD is dependent largely on the maintenance of sufficient aerobic capacity and strength to perform daily activities. Although peak aerobic capacity is widely recognized to decline with age, its rate of decline has been

  12. A proposed aerobic granules size development scheme for aerobic granulation process.

    PubMed

    Dahalan, Farrah Aini; Abdullah, Norhayati; Yuzir, Ali; Olsson, Gustaf; Salmiati; Hamdzah, Myzairah; Din, Mohd Fadhil Mohd; Ahmad, Siti Aqlima; Khalil, Khalilah Abdul; Anuar, Aznah Nor; Noor, Zainura Zainon; Ujang, Zaini

    2015-04-01

    Aerobic granulation is increasingly used in wastewater treatment due to its unique physical properties and microbial functionalities. Granule size defines the physical properties of granules based on biomass accumulation. This study aims to determine the profile of size development under two physicochemical conditions. Two identical bioreactors namely Rnp and Rp were operated under non-phototrophic and phototrophic conditions, respectively. An illustrative scheme was developed to comprehend the mechanism of size development that delineates the granular size throughout the granulation. Observations on granules' size variation have shown that activated sludge revolutionised into the form of aerobic granules through the increase of biomass concentration in bioreactors which also determined the changes of granule size. Both reactors demonstrated that size transformed in a similar trend when tested with and without illumination. Thus, different types of aerobic granules may increase in size in the same way as recommended in the aerobic granule size development scheme. PMID:25661308

  13. Ecophysiological Characteristics of Obligate Methanotrophic Bacteria and Methane Oxidation In Situ

    NASA Technical Reports Server (NTRS)

    King, Gary M.

    1993-01-01

    Most of the obligate methane-oxidizing bacteria (MOB) described to date are neutrophilic mesophiles that grow optimally in dilute media. Kinetic analyses generally indicate that bacterial methane uptake occurs by transport systems with a K(sub m) greater than l micronM. These and other properties of MOB are inconsistent with characteristics of methane oxidation in situ. The inconsistencies indicate a need for greater attention to the ecophysiological characteristics of isolates and the design of enrichment and isolation schemes which emphasize ecologically relevant parameters (e.g., low temperature, limited and diverse substrate availability, low water potential).

  14. AEROBIC DENITRIFICATION: IMPLICATIONS FOR NITROGEN FATE MODELING

    EPA Science Inventory

    In the Mississippi, as well as most nitrogen-degraded rivers and streams, NO3- is the dominant N species and therefore understanding its biogeochemical behavior is critical for accurate nitrogen fate modeling. To our knowledge this is the first work to report aerobic denitrificat...

  15. Aerobic Exercise Prescription for Rheumatoid Arthritics.

    ERIC Educational Resources Information Center

    Evans, Blanche W.; Williams, Hilda L.

    The use of exercise as a general treatment for rheumatoid arthritics (RA) has included range of motion, muscular strength, water exercise and rest therapy while virtually ignoring possible benefits of aerobic exercise. The purposes of this project were to examine the guidelines for exercise prescription in relation to this special population and…

  16. Media for the aerobic growth of campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of agar and sodium bicarbonate (NaHCO3) concentration on aerobic growth of Campylobacter in a fumarate-pyruvate medium was examined. The broth medium was supplemented with 0.0 to 0.2% agar and inoculated with 106 CFU/ml of Campylobacter coli 33559, Campylobacter fetus 27349, Campylobacter...

  17. Anaerobic and aerobic transformation of TNT

    SciTech Connect

    Kulpa, C.F.; Boopathy, R.; Manning, J.

    1996-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.

  18. Response of aerobic rice to Piriformospora indica.

    PubMed

    Das, Joy; Ramesh, K V; Maithri, U; Mutangana, D; Suresh, C K

    2014-03-01

    Rice cultivation under aerobic condition not only saves water but also opens up a splendid scope for effective application of beneficial root symbionts in rice crop unlike conventional puddled rice cultivation where water logged condition acts as constraint for easy proliferation of various beneficial soil microorganisms like arbuscular mycorrhizal (AM) fungi. Keeping these in view, an in silico investigation were carried out to explore the interaction of hydrogen phosphate with phosphate transporter protein (PTP) from P. indica. This was followed by greenhouse investigation to study the response of aerobic rice to Glomusfasciculatum, a conventional P biofertilizer and P. indica, an alternative to AM fungi. Computational studies using ClustalW tool revealed several conserved motifs between the phosphate transporters from Piriformospora indica and 8 other Glomus species. The 3D model of PTP from P. indica resembling "Mayan temple" was successfully docked onto hydrogen phosphate, indicating the affinity of this protein for inorganic phosphorus. Greenhouse studies revealed inoculation of aerobic rice either with P. indica, G. fasciculatum or both significantly enhanced the plant growth, biomass and yield with higher NPK, chlorophyll and sugar compared to uninoculated ones, P. indica inoculated plants being superior. A significantly enhanced activity of acid phosphatase and alkaline phosphatase were noticed in the rhizosphere soil of rice plants inoculated either with P. indica, G. fasciculatum or both, contributing to higher P uptake. Further, inoculation of aerobic rice plants with P. indica proved to be a better choice as a potential biofertilizer over mycorrhiza. PMID:24669667

  19. Evolution of Molybdenum Nitrogenase during the Transition from Anaerobic to Aerobic Metabolism

    PubMed Central

    Boyd, Eric S.; Costas, Amaya M. Garcia; Hamilton, Trinity L.; Mus, Florence

    2015-01-01

    ABSTRACT Molybdenum nitrogenase (Nif), which catalyzes the reduction of dinitrogen to ammonium, has modulated the availability of fixed nitrogen in the biosphere since early in Earth's history. Phylogenetic evidence indicates that oxygen (O2)-sensitive Nif emerged in an anaerobic archaeon and later diversified into an aerobic bacterium. Aerobic bacteria that fix N2 have adapted a number of strategies to protect Nif from inactivation by O2, including spatial and temporal segregation of Nif from O2 and respiratory consumption of O2. Here we report the complement of Nif-encoding genes in 189 diazotrophic genomes. We show that the evolution of Nif during the transition from anaerobic to aerobic metabolism was accompanied by both gene recruitment and loss, resulting in a substantial increase in the number of nif genes. While the observed increase in the number of nif genes and their phylogenetic distribution are strongly correlated with adaptation to utilize O2 in metabolism, the increase is not correlated with any of the known O2 protection mechanisms. Rather, gene recruitment appears to have been in response to selective pressure to optimize Nif synthesis to meet fixed N demands associated with aerobic productivity and to more efficiently regulate Nif under oxic conditions that favor protein turnover. Consistent with this hypothesis, the transition of Nif from anoxic to oxic environments is associated with a shift from posttranslational regulation in anaerobes to transcriptional regulation in obligate aerobes and facultative anaerobes. Given that fixed nitrogen typically limits ecosystem productivity, our observations further underscore the dynamic interplay between the evolution of Earth's oxygen, nitrogen, and carbon biogeochemical cycles. IMPORTANCE Molybdenum nitrogenase (Nif), which catalyzes the reduction of dinitrogen to ammonium, has modulated the availability of fixed nitrogen in the biosphere since early in Earth's history. Nif emerged in an anaerobe and later diversified into aerobes. Here we show that the transition of Nif from anaerobic to aerobic metabolism was accompanied by both gene recruitment and gene loss, resulting in a substantial increase in the number of nif genes. While the observed increase in the number of nif genes is strongly correlated with adaptation to utilize O2 in metabolism, the increase is not correlated with any of the known O2 protective mechanisms. Rather, gene recruitment was likely a response to more efficiently regulate Nif under oxic conditions that favor protein turnover. PMID:25733617

  20. Selecting anti-microbial treatment of aerobic vaginitis.

    PubMed

    Donders, Gilbert G G; Ruban, Katerina; Bellen, Gert

    2015-05-01

    Aerobic vaginitis (AV) is a vaginal infectious condition which is often confused with bacterial vaginosis (BV) or with the intermediate microflora as diagnosed by Nugent's method to detect BV on Gram-stained specimens. However, although both conditions reflect a state of lactobacillary disruption in the vagina, leading to an increase in pH, BV and AV differ profoundly. While BV is a noninflammatory condition composed of a multiplex array of different anaerobic bacteria in high quantities, AV is rather sparely populated by one or two enteric commensal flora bacteria, like Streptococcus agalactiae, Staphylocuccus aureus, or Escherichia coli. AV is typically marked by either an increased inflammatory response or by prominent signs of epithelial atrophy or both. The latter condition, if severe, is also called desquamative inflammatory vaginitis. As AV is per exclusionem diagnosed by wet mount microscopy, it is a mistake to treat just vaginal culture results. Vaginal cultures only serve as follow-up data in clinical research projects and are at most used in clinical practice to confirm the diagnosis or exclude Candida infection. AV requires treatment based on microscopy findings and a combined local treatment with any of the following which may yield the best results: antibiotic (infectious component), steroids (inflammatory component), and/or estrogen (atrophy component). In cases with Candida present on microscopy or culture, antifungals must be tried first in order to see if other treatment is still needed. Vaginal rinsing with povidone iodine can provide rapid relief of symptoms but does not provide long-term reduction of bacterial loads. Local antibiotics most suitable are preferably non-absorbed and broad spectrum, especially those covering enteric gram-positive and gram-negative aerobes, like kanamycin. To achieve rapid and short-term improvement of severe symptoms, oral therapy with amoxyclav or moxifloxacin can be used, especially in deep dermal vulvitis and colpitis infections with group B streptococci or (methicillin resistant) Staphylococcus aureus. Since the latter colonizations are frequent, but seldom inflammatory infections, we in general discourage the use of oral antibiotics in women with AV. In cases with a severe atrophy component (more than 10 % of epithelial cells are of the parabasal type), local estrogens can be used; and in postmenopausal or breast cancer patients with a contraindication for estrogens, even a combination of probiotics with an ultra-low dose of local estriol may be considered. PMID:25896749

  1. Dissolution of Fe(III)(hydr)oxides by an Aerobic Bacterium

    SciTech Connect

    Maurice, P.

    2004-12-13

    This project investigated the effects of an aerobic Pseudomonas mendocina bacterium on the dissolution of Fe(III)(hydr)oxides. The research is important because metals and radionuclides that adsorb to Fe(III)(hydr)oxides could potentially be remobilized by dissolving bacteria. We showed that P. mendocina is capable of dissolving Fe-bearing minerals by a variety of mechanisms, including production of siderophores, pH changes, and formation of reductants. The production of siderophores by P. mendocina was quantified under a variety of growth conditions. Finally, we demonstrated that microbial siderophores may adsorb to and enhance dissolution of clay minerals.

  2. Effect of temperature on mineralization by heterotrophic bacteria

    SciTech Connect

    Tison, D.L.; Pope, D.H.

    1980-03-01

    When pure cultures of the bacteria Pseudomonas fluorescens (a psychrotroph), Escherichia coli (a mesophile), and SRL 261 (a thermophile) were shifted away from temperatures to which they were adapted, the percentage of substrate mineralized increased (percent mineralized = (substrate respired to CO/sub 2/)/(substrate respired to CO/sub 2/ + substrate incorporated into biomass) x 100). The increase in the percent mineralized was larger for larger temperature shifts. Similar responses were observed when natural heterotrophic bacterial populations from sediments of Lake George, N.Y., and a thermophilic algal-bacterial mat community at the Savannah River Plant, Aiken, S.C., were subjected to temperature shifts. These results suggest that an increase in the percent mineralized may be an indication of thermal stress in bacterial populations.

  3. RECOVERY OF BACTERIA FROM BROILER CARCASS RESPIRATORY TRACTS BEFORE AND AFTER IMMERSION SCALDING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We previously reported an increase in the numbers of total aerobic bacteria, coliforms, and E. coli recovered from broiler carcass respiratory tracts following commercial scalding. To determine if this increase during immersion scalding (presumed to be induced by changes in internal and external ca...

  4. Active sulfur cycling by diverse mesophilic and thermophilic microorganisms in terrestrial mud volcanoes of Azerbaijan.

    PubMed

    Green-Saxena, A; Feyzullayev, A; Hubert, C R J; Kallmeyer, J; Krueger, M; Sauer, P; Schulz, H-M; Orphan, V J

    2012-12-01

    Terrestrial mud volcanoes (TMVs) represent geochemically diverse habitats with varying sulfur sources and yet sulfur cycling in these environments remains largely unexplored. Here we characterized the sulfur-metabolizing microorganisms and activity in four TMVs in Azerbaijan. A combination of geochemical analyses, biological rate measurements and molecular diversity surveys (targeting metabolic genes aprA and dsrA and SSU ribosomal RNA) supported the presence of active sulfur-oxidizing and sulfate-reducing guilds in all four TMVs across a range of physiochemical conditions, with diversity of these guilds being unique to each TMV. The TMVs varied in potential sulfate reduction rates (SRR) by up to four orders of magnitude with highest SRR observed in sediments where in situ sulfate concentrations were highest. Maximum temperatures at which SRR were measured was 60°C in two TMVs. Corresponding with these trends in SRR, members of the potentially thermophilic, spore-forming, Desulfotomaculum were detected in these TMVs by targeted 16S rRNA analysis. Additional sulfate-reducing bacterial lineages included members of the Desulfobacteraceae and Desulfobulbaceae detected by aprA and dsrA analyses and likely contributing to the mesophilic SRR measured. Phylotypes affiliated with sulfide-oxidizing Gamma- and Betaproteobacteria were abundant in aprA libraries from low sulfate TMVs, while the highest sulfate TMV harboured 16S rRNA phylotypes associated with sulfur-oxidizing Epsilonproteobacteria. Altogether, the biogeochemical and microbiological data indicate these unique terrestrial habitats support diverse active sulfur-cycling microorganisms reflecting the in situ geochemical environment. PMID:23116231

  5. Bacteria isolated from amoebae/bacteria consortium

    DOEpatents

    Tyndall, Richard L. (Clinton, TN)

    1995-01-01

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  6. Bacteria isolated from amoebae/bacteria consortium

    DOEpatents

    Tyndall, R.L.

    1995-05-30

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  7. Systematic investigation and microbial community profile of indole degradation processes in two aerobic activated sludge systems.

    PubMed

    Ma, Qiao; Qu, Yuanyuan; Zhang, Xuwang; Liu, Ziyan; Li, Huijie; Zhang, Zhaojing; Wang, Jingwei; Shen, Wenli; Zhou, Jiti

    2015-01-01

    Indole is widely spread in various environmental matrices. Indole degradation by bacteria has been reported previously, whereas its degradation processes driven by aerobic microbial community were as-yet unexplored. Herein, eight sequencing batch bioreactors fed with municipal and coking activated sludges were constructed for aerobic treatment of indole. The whole operation processes contained three stages, i.e. stage I, glucose and indole as carbon sources; stage II, indole as carbon source; and stage III, indole as carbon and nitrogen source. Indole could be completely removed in both systems. Illumina sequencing revealed that alpha diversity was reduced after indole treatment and microbial communities were significantly distinct among the three stages. At genus level, Azorcus and Thauera were dominant species in stage I in both systems, while Alcaligenes, Comamonas and Pseudomonas were the core genera in stage II and III in municipal sludge system, Alcaligenes and Burkholderia in coking sludge system. In addition, four strains belonged to genera Comamonas, Burkholderia and Xenophilus were isolated using indole as sole carbon source. Burkholderia sp. IDO3 could remove 100?mg/L indole completely within 14?h, the highest degradation rate to date. These findings provide novel information and enrich our understanding of indole aerobic degradation processes. PMID:26657581

  8. Reductive dechlorination of tri- and tetrachloroethylenes depends on transition from aerobic to anaerobic conditions

    SciTech Connect

    Kastner, M. )

    1991-07-01

    Aerobic enrichment cultures from contaminated groundwaters dechlorinated trichloroethylene (TCE) (14.6 mg/liter; 111 {mu}mol/liter) and tetrachloroethylene (PCE) (16.2 mg/liter; 98 {mu}mol/liter) reductively within 4 days after the transition from aerobic to anaerobic conditions. The transformation products were equimolar amounts of cis-1,2-dichloroethylene and traces of 1,1-dichloroethylene. No other chlorinated product and no methane were detected. The change was accompanied by the release of sulfide, which caused a decrease in the redox potential from 0 - {minus}150 mV. In sterile control experiments, sulfide led to the abiotic formation of traces of 1,1-dichloroethylene without cis-1,2-dichloroethylene production. The reductive dechlorination of PCE via TCE depended on these specific transition conditions after consumption of the electron acceptor oxygen or nitrate. Repeated feeding of TCE or PCE to cultures after the change to anaerobic conditions yielded no further dechlorination. Only aerobic subcultures with an air/liquid ratio of 1:4 maintained dechlorination activities; anaerobic subcultures showed no transformation. Bacteria from noncontaminated sites showed no reduction under the same conditions.

  9. Systematic investigation and microbial community profile of indole degradation processes in two aerobic activated sludge systems

    PubMed Central

    Ma, Qiao; Qu, Yuanyuan; Zhang, Xuwang; Liu, Ziyan; Li, Huijie; Zhang, Zhaojing; Wang, Jingwei; Shen, Wenli; Zhou, Jiti

    2015-01-01

    Indole is widely spread in various environmental matrices. Indole degradation by bacteria has been reported previously, whereas its degradation processes driven by aerobic microbial community were as-yet unexplored. Herein, eight sequencing batch bioreactors fed with municipal and coking activated sludges were constructed for aerobic treatment of indole. The whole operation processes contained three stages, i.e. stage I, glucose and indole as carbon sources; stage II, indole as carbon source; and stage III, indole as carbon and nitrogen source. Indole could be completely removed in both systems. Illumina sequencing revealed that alpha diversity was reduced after indole treatment and microbial communities were significantly distinct among the three stages. At genus level, Azorcus and Thauera were dominant species in stage I in both systems, while Alcaligenes, Comamonas and Pseudomonas were the core genera in stage II and III in municipal sludge system, Alcaligenes and Burkholderia in coking sludge system. In addition, four strains belonged to genera Comamonas, Burkholderia and Xenophilus were isolated using indole as sole carbon source. Burkholderia sp. IDO3 could remove 100?mg/L indole completely within 14?h, the highest degradation rate to date. These findings provide novel information and enrich our understanding of indole aerobic degradation processes. PMID:26657581

  10. The role of autoinducer-2 in aerobic granulation using alternating feed loadings strategy.

    PubMed

    Sun, Supu; Liu, Xiang; Ma, Buyun; Wan, Chunli; Lee, Duu-Jong

    2016-02-01

    Quorum sensing (QS) plays an important role in aerobic granulation while how QS system regulates the formation of aerobic granules needs further discussion. This study cultivated activated sludge in two identical sequencing batch reactors (R1 and R2) at different influent organic loading rate (OLR) strategies: R1 was operated using constant OLR (around 8.0kg/m(3)d), while R2 was operated at alternating OLR (4.0-17.0kg/m(3)d). Microbial aggregates appeared in R2 on day 19, while the morphology of sludge in R1 changed little compared with the initial sludge. The concentration of autoinducer-2 (AI-2) in R2 showed an ascending trend, along with the increase of cell adhesiveness. The total extracellular polymeric substances (EPS) amount and large molecular weight EPS of R2 rose steadily, which was different from R1. Some bacteria able to self-aggregate and promote EPS secretion were exclusive in R2. A mechanism about aerobic granulation at alternating OLR was proposed. PMID:26638134

  11. Methane oxidation in a crude oil contaminated aquifer: Delineation of aerobic reactions at the plume fringes

    USGS Publications Warehouse

    Amos, R.T.; Bekins, B.A.; Delin, G.N.; Cozzarelli, I.M.; Blowes, D.W.; Kirshtein, J.D.

    2011-01-01

    High resolution direct-push profiling over short vertical distances was used to investigate CH4 attenuation in a petroleum contaminated aquifer near Bemidji, Minnesota. The contaminant plume was delineated using dissolved gases, redox sensitive components, major ions, carbon isotope ratios in CH4 and CO2, and the presence of methanotrophic bacteria. Sharp redox gradients were observed near the water table. Shifts in ??13CCH4 from an average of - 57.6??? (?? 1.7???) in the methanogenic zone to - 39.6??? (?? 8.7???) at 105 m downgradient, strongly suggest CH4 attenuation through microbially mediated degradation. In the downgradient zone the aerobic/anaerobic transition is up to 0.5 m below the water table suggesting that transport of O2 across the water table is leading to aerobic degradation of CH4 at this interface. Dissolved N2 concentrations that exceeded those expected for water in equilibrium with the atmosphere indicated bubble entrapment followed by preferential stripping of O2 through aerobic degradation of CH4 or other hydrocarbons. Multivariate and cluster analysis were used to distinguish between areas of significant bubble entrapment and areas where other processes such as the infiltration of O 2 rich recharge water were important O2 transport mechanisms. ?? 2011 Elsevier B.V. All rights reserved.

  12. Aerobic cyanide degradation by bacterial isolates from cassava factory wastewater.

    PubMed

    Kandasamy, Sujatha; Dananjeyan, Balachandar; Krishnamurthy, Kumar; Benckiser, Gero

    2015-01-01

    Ten bacterial strains that utilize cyanide (CN) as a nitrogen source were isolated from cassava factory wastewater after enrichment in a liquid media containing sodium cyanide (1 mM) and glucose (0.2% w/v). The strains could tolerate and grow in cyanide concentrations of up to 5 mM. Increased cyanide levels in the media caused an extension of lag phase in the bacterial growth indicating that they need some period of acclimatisation. The rate of cyanide removal by the strains depends on the initial cyanide and glucose concentrations. When initial cyanide and glucose concentrations were increased up to 5 mM, cyanide removal rate increased up to 63 and 61 per cent by Bacillus pumilus and Pseudomonas putida. Metabolic products such as ammonia and formate were detected in culture supernatants, suggesting a direct hydrolytic pathway without an intermediate formamide. The study clearly demonstrates the potential of aerobic treatment with cyanide degrading bacteria for cyanide removal in cassava factory wastewaters. PMID:26413045

  13. Aerobic cyanide degradation by bacterial isolates from cassava factory wastewater

    PubMed Central

    Kandasamy, Sujatha; Dananjeyan, Balachandar; Krishnamurthy, Kumar; Benckiser, Gero

    2015-01-01

    Ten bacterial strains that utilize cyanide (CN) as a nitrogen source were isolated from cassava factory wastewater after enrichment in a liquid media containing sodium cyanide (1 mM) and glucose (0.2% w/v). The strains could tolerate and grow in cyanide concentrations of up to 5 mM. Increased cyanide levels in the media caused an extension of lag phase in the bacterial growth indicating that they need some period of acclimatisation. The rate of cyanide removal by the strains depends on the initial cyanide and glucose concentrations. When initial cyanide and glucose concentrations were increased up to 5 mM, cyanide removal rate increased up to 63 and 61 per cent by Bacillus pumilus and Pseudomonas putida. Metabolic products such as ammonia and formate were detected in culture supernatants, suggesting a direct hydrolytic pathway without an intermediate formamide. The study clearly demonstrates the potential of aerobic treatment with cyanide degrading bacteria for cyanide removal in cassava factory wastewaters. PMID:26413045

  14. Halophilic (aerobic) bacterial growth rate of mangrove ecosystem.

    PubMed

    Khan, A Saleem; Ali, M Sheik; Baig, I Juned Ahmed

    2009-09-01

    Mangroves are woody specialized trees of tropics and are valuable flora contributing to economical, ecological, scientific and cultural resources. They thrive in salty environments like coastal regions and are aid towards disaster management facing the onslaught of giant waves such as Tsunami. Analysis of mangrove soil on the banks of the Adyar river behind the Theosophical society campus, Adyar, Chennai, India, gave a startling revelation of microorganisms that can tolerate different salinity ranges. Previous studies in Pichavaram delta, have reported bacterial isolates such as nitrogen fixing bacteria, halophiles and several others. However their efficiency in the growth of mangrove forest has been studied to a lesser extent. The present study has been designed and formulated to estimate halophilic (aerobic) bacterial load from mangroves soil sample based on depth and salinity of the soil and further the efficiency if any of these isolates in the growth of mangroves. Results have been correlated and a cohesive conclusion reached for further intensive research. This study throws light on the ecology of the bacterial population in the coastal marine environment inhabited bymangroves and its possible role in disaster mitigation. PMID:20136052

  15. Nitrogen Removal from Micro-Polluted Reservoir Water by Indigenous Aerobic Denitrifiers

    PubMed Central

    Huang, Ting-Lin; Zhou, Shi-Lei; Zhang, Hai-Han; Zhou, Na; Guo, Lin; Di, Shi-Yu; Zhou, Zi-Zhen

    2015-01-01

    Treatment of micro-polluted source water is receiving increasing attention because of environmental awareness on a global level. We isolated and identified aerobic denitrifying bacteria Zoogloea sp. N299, Acinetobacter sp. G107, and Acinetobacter sp. 81Y and used these to remediate samples of their native source water. We first domesticated the isolated strains in the source water, and the 48-h nitrate removal rates of strains N299, G107, and 81Y reached 33.69%, 28.28%, and 22.86%, respectively, with no nitrite accumulation. We then conducted a source-water remediation experiment and cultured the domesticated strains (each at a dry cell weight concentration of 0.4 ppm) together in a sample of source water at 20–26 °C and a dissolved oxygen concentration of 3–7 mg/L for 60 days. The nitrate concentration of the system decreased from 1.57 ± 0.02 to 0.42 ± 0.01 mg/L and that of a control system decreased from 1.63 ± 0.02 to 1.30 ± 0.01 mg/L, each with no nitrite accumulation. Total nitrogen of the bacterial system changed from 2.31 ± 0.12 to 1.09 ± 0.01 mg/L, while that of the control system changed from 2.51 ± 0.13 to 1.72 ± 0.06 mg/L. The densities of aerobic denitrification bacteria in the experimental and control systems ranged from 2.8 × 104 to 2 × 107 cfu/mL and from 7.75 × 103 to 5.5 × 105 cfu/mL, respectively. The permanganate index in the experimental and control systems decreased from 5.94 ± 0.12 to 3.10 ± 0.08 mg/L and from 6.02 ± 0.13 to 3.61 ± 0.11 mg/L, respectively, over the course of the experiment. Next, we supplemented samples of the experimental and control systems with additional bacteria or additional source water and cultivated the systems for another 35 days. The additional bacteria did little to improve the water quality. The additional source water provided supplemental carbon and brought the nitrate removal rate in the experimental system to 16.97%, while that in the control system reached only 3.01%, with no nitrite accumulation in either system. Our results show that aerobic denitrifying bacteria remain highly active after domestication and demonstrate the applicability of such organisms in the bioremediation of oligotrophic ecosystems. PMID:25867475

  16. [Aerobic vaginitis--diagnostic problems and treatment].

    PubMed

    Romanik, Ma?gorzata; Wojciechowska-Wieja, Anna; Martirosian, Gayane

    2007-06-01

    The diagnostic criteria and treatment of aerobic vaginitis--AV--have been summarized in this review. An expansion of mixed aerobic microflora, especially Group B Streptococcus--GBS, Escherichia coli--E. coli, Enterococcus spp., and the development of inflammation of the vaginal mucous membrane due to a decreasing amount of Lactobacillus spp., have been observed in women with AV. Disruptions of the vaginal ecosystem during AV cause an increase in pH to >6, a decrease in lactates concentration and an increase in proinflammatory cytokines concentration in vaginal discharge. An optimal treatment scheme for AV, which includes antibacterial agents and simultaneously normalizes the vaginal ecosystem, has not been established until today. PMID:17899708

  17. Nitrification and aerobic denitrification in anoxic-aerobic sequencing batch reactor.

    PubMed

    Alzate Marin, Juan C; Caravelli, Alejandro H; Zaritzky, Noemí E

    2016-01-01

    The aim of this study was to evaluate the feasibility of achieving nitrogen (N) removal using a lab-scale sequencing batch reactor (SBR) exposed to anoxic/aerobic (AN/OX) phases, focusing to achieve aerobic denitrification. This process will minimize emissions of N2O greenhouse gas. The effects of different operating parameters on the reactor performance were studied: cycle duration, AN/OX ratio, pH, dissolved oxygen concentration (DOC), and organic load. The highest inorganic N removal (NiR), close to 70%, was obtained at pH=7.5, low organic load (440mgCOD/(Lday)) and high aeration given by 12h cycle, AN/OX ratio=0.5:1.0 and DOC higher than 4.0mgO2/L. Nitrification followed by high-rate aerobic denitrification took place during the aerobic phase. Aerobic denitrification could be attributed to Tetrad-forming organisms (TFOs) with phenotype of glycogen accumulating organisms using polyhydroxyalkanoate and/or glycogen storage. The proposed AN/OX system constitutes an eco-friendly N removal process providing N2 as the end product. PMID:26512862

  18. Modeling aerobic biodegradation in the capillary fringe.

    PubMed

    Luo, Jian; Kurt, Zohre; Hou, Deyi; Spain, Jim C

    2015-02-01

    Vapor intrusion from volatile subsurface contaminants can be mitigated by aerobic biodegradation. Laboratory column studies with contaminant sources of chlorobenzene and a mixture of chlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene showed that contaminants were rapidly degraded in thin reactive zones with high biomass and low substrate concentrations in the vicinity of the capillary fringe. Such behavior was well characterized by a model that includes oxygen-, substrate-, and biomass-dependent biodegradation kinetics along with diffusive transport processes. An analytical solution was derived to provide theoretical support for the simplification of reaction kinetics and the approximation of reactive zone location and mass flux relationships at steady state. Results demonstrate the potential of aerobic natural attenuation in the capillary fringe for preventing contaminant migration in the unsaturated zone. The solution indicates that increasing contaminant mass flux into the column creates a thinner reactive zone and pushes it toward the oxygen boundary, resulting in a shorter distance to the oxygen source and a larger oxygen mass flux that balances the contaminant mass flux. As a consequence, the aerobic biodegradation can reduce high contaminant concentrations to low levels within the capillary fringe and unsaturated zone. The results are consistent with the observations of thin reactive layers at the interface in unsaturated zones. The model considers biomass while including biodegradation in the capillary fringe and unsaturated zone and clearly demonstrates that microbial communities capable of using the contaminants as electron donors may lead to instantaneous degradation kinetics in the capillary fringe and unsaturated zone. PMID:25548946

  19. Enhancement of methane production in mesophilic anaerobic digestion of secondary sewage sludge by advanced thermal hydrolysis pretreatment.

    PubMed

    Abelleira-Pereira, Jose M; Pérez-Elvira, Sara I; Sánchez-Oneto, Jezabel; de la Cruz, Roberto; Portela, Juan R; Nebot, Enrique

    2015-03-15

    Studies on the development and evolution of anaerobic digestion (AD) pretreatments are nowadays becoming widespread, due to the outstanding benefits that these processes could entail in the management of sewage sludge. Production of sewage sludge in wastewater treatment plants (WWTPs) is becoming an extremely important environmental issue. The work presented in this paper is a continuation of our previous studies with the aim of understanding and developing the advanced thermal hydrolysis (ATH) process. ATH is a novel AD pretreatment based on a thermal hydrolysis (TH) process plus hydrogen peroxide (H2O2) addition that takes advantage of a peroxidation/direct steam injection synergistic effect. The main goal of the present research was to compare the performance of TH and ATH, conducted at a wide range of operating conditions, as pretreatments of mesophilic AD with an emphasis on methane production enhancement as a key parameter and its connection with the sludge solubilization. Results showed that both TH and ATH patently improved methane production in subsequent mesophilic BMP (biochemical methane potential) tests in comparison with BMP control tests (raw secondary sewage sludge). Besides other interesting results and discussions, a promising result was obtained since ATH, operated at temperature (115 °C), pretreatment time (5 min) and pressure (1 bar) considerably below those typically used in TH (170 °C, 30 min, 8 bar), managed to enhance the methane production in subsequent mesophilic BMP tests [biodegradability factor (fB) = cumulative CH4production/cumulative CH4production (Control) = 1.51 ± 0.01] to quite similar levels than conventional TH pretreatment [fB = 1.52 ± 0.03]. PMID:25682559

  20. CHAPTER IV-2 BACTERIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Entomopathogenic bacteria provide an alternative to chemical pesticides used in insect control programs. Today, the principal microbial insecticides utilize spore forming bacteria or toxins produced by these bacteria as their active ingredients, either in formulations or by incorporation of toxin g...

  1. Intrinsic contributions of polar amino acid residues toward thermal stability of an ABC-ATPase of mesophilic origin.

    PubMed

    Sarin, Jyoti; Raghava, Gajendra P S; Chakraborti, Pradip K

    2003-09-01

    The nucleotide-binding subunit of phosphate-specific transporter (PstB) from mesophilic bacterium, Mycobacterium tuberculosis, is a unique ATP-binding cassette (ABC) ATPase because of its unusual ability to hydrolyze ATP at high temperature. In an attempt to define the basis of thermostability, we took a theoretical approach and compared amino acid composition of this protein to that of other PstBs from available bacterial genomes. Interestingly, based on the content of polar amino acids, this protein clustered with the thermophiles. PMID:12931011

  2. High rate mesophilic, thermophilic, and temperature phased anaerobic digestion of waste activated sludge: A pilot scale study

    SciTech Connect

    Bolzonella, David; Cavinato, Cristina; Fatone, Francesco; Pavan, Paolo; Cecchi, Franco

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer High temperatures were tested in single and two-stage anaerobic digestion of waste activated sludge. Black-Right-Pointing-Pointer The increased temperature demonstrated the possibility of improving typical yields of the conventional mesophilic process. Black-Right-Pointing-Pointer The temperature phased anaerobic digestion process (65 + 55 Degree-Sign C) showed the best performances with yields of 0.49 m{sup 3}/kgVS{sub fed}. Black-Right-Pointing-Pointer Ammonia and phosphate released from solids destruction determined the precipitation of struvite in the reactor. - Abstract: The paper reports the findings of a two-year pilot scale experimental trial for the mesophilic (35 Degree-Sign C), thermophilic (55 Degree-Sign C) and temperature phased (65 + 55 Degree-Sign C) anaerobic digestion of waste activated sludge. During the mesophilic and thermophilic runs, the reactor operated at an organic loading rate of 2.2 kgVS/m{sup 3}d and a hydraulic retention time of 20 days. In the temperature phased run, the first reactor operated at an organic loading rate of 15 kgVS/m{sup 3}d and a hydraulic retention time of 2 days while the second reactor operated at an organic loading rate of 2.2 kgVS/m{sup 3}d and a hydraulic retention time of 18 days (20 days for the whole temperature phased system). The performance of the reactor improved with increases in temperature. The COD removal increased from 35% in mesophilic conditions, to 45% in thermophilic conditions, and 55% in the two stage temperature phased system. As a consequence, the specific biogas production increased from 0.33 to 0.45 and to 0.49 m{sup 3}/kgVS{sub fed} at 35, 55, and 65 + 55 Degree-Sign C, respectively. The extreme thermophilic reactor working at 65 Degree-Sign C showed a high hydrolytic capability and a specific yield of 0.33 gCOD (soluble) per gVS{sub fed}. The effluent of the extreme thermophilic reactor showed an average concentration of soluble COD and volatile fatty acids of 20 and 9 g/l, respectively. Acetic and propionic acids were the main compounds found in the acids mixture. Because of the improved digestion efficiency, organic nitrogen and phosphorus were solubilised in the bulk. Their concentration, however, did not increase as expected because of the formation of salts of hydroxyapatite and struvite inside the reactor.

  3. Aerobic methanotrophic communities at the Red Sea brine-seawater interface

    PubMed Central

    Abdallah, Rehab Z.; Adel, Mustafa; Ouf, Amged; Sayed, Ahmed; Ghazy, Mohamed A.; Alam, Intikhab; Essack, Magbubah; Lafi, Feras F.; Bajic, Vladimir B.; El-Dorry, Hamza; Siam, Rania

    2014-01-01

    The central rift of the Red Sea contains 25 brine pools with different physicochemical conditions, dictating the diversity and abundance of the microbial community. Three of these pools, the Atlantis II, Kebrit and Discovery Deeps, are uniquely characterized by a high concentration of hydrocarbons. The brine-seawater interface, described as an anoxic-oxic (brine-seawater) boundary, is characterized by a high methane concentration, thus favoring aerobic methane oxidation. The current study analyzed the aerobic free–living methane-oxidizing bacterial communities that potentially contribute to methane oxidation at the brine-seawater interfaces of the three aforementioned brine pools, using metagenomic pyrosequencing, 16S rRNA pyrotags and pmoA library constructs. The sequencing of 16S rRNA pyrotags revealed that these interfaces are characterized by high microbial community diversity. Signatures of aerobic methane-oxidizing bacteria were detected in the Atlantis II Interface (ATII-I) and the Kebrit Deep Upper (KB-U) and Lower (KB-L) brine-seawater interfaces. Through phylogenetic analysis of pmoA, we further demonstrated that the ATII-I aerobic methanotroph community is highly diverse. We propose four ATII-I pmoA clusters. Most importantly, cluster 2 groups with marine methane seep methanotrophs, and cluster 4 represent a unique lineage of an uncultured bacterium with divergent alkane monooxygenases. Moreover, non-metric multidimensional scaling (NMDS) based on the ordination of putative enzymes involved in methane metabolism showed that the Kebrit interface layers were distinct from the ATII-I and DD-I brine-seawater interfaces. PMID:25295031

  4. Aerobic digestion reduces the quantity of antibiotic resistance genes in residual municipal wastewater solids

    PubMed Central

    Burch, Tucker R.; Sadowsky, Michael J.; LaPara, Timothy M.

    2012-01-01

    Numerous initiatives have been undertaken to circumvent the problem of antibiotic resistance, including the development of new antibiotics, the use of narrow spectrum antibiotics, and the reduction of inappropriate antibiotic use. We propose an alternative but complimentary approach to reduce antibiotic resistant bacteria (ARB) by implementing more stringent technologies for treating municipal wastewater, which is known to contain large quantities of ARB and antibiotic resistance genes (ARGs). In this study, we investigated the ability of conventional aerobic digestion to reduce the quantity of ARGs in untreated wastewater solids. A bench-scale aerobic digester was fed untreated wastewater solids collected from a full-scale municipal wastewater treatment facility. The reactor was operated under semi-continuous flow conditions for more than 200 days at a residence time of approximately 40 days. During this time, the quantities of tet(A), tet(W), and erm(B) decreased by more than 90%. In contrast, intI1 did not decrease, and tet(X) increased in quantity by 5-fold. Following operation in semi-continuous flow mode, the aerobic digester was converted to batch mode to determine the first-order decay coefficients, with half-lives ranging from as short as 2.8 days for tet(W) to as long as 6.3 days for intI1. These results demonstrated that aerobic digestion can be used to reduce the quantity of ARGs in untreated wastewater solids, but that rates can vary substantially depending on the reactor design (i.e., batch vs. continuous-flow) and the specific ARG. PMID:23407455

  5. Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions

    SciTech Connect

    Kim, Dong-Hoon; Oh, Sae-Eun

    2011-09-15

    Highlights: > High-solids (dry) anaerobic digestion is attracting a lot of attention these days. > One reactor was fed with food waste (FW) and paper waste. > Maximum biogas production rate of 5.0 m{sup 3}/m{sup 3}/d was achieved at HRT 40 d and 40% TS. > The other reactor was fed with FW and livestock waste (LW). > Until a 40% LW content increase, the reactor exhibited a stable performance. - Abstract: With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO{sub 2} emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH{sub 4} production yield (MPY) and VS reduction achieved in this condition were 5.0 m{sup 3}/m{sup 3}/d, 0.25 m{sup 3} CH{sub 4}/g COD{sub added}, and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m{sup 3}/m{sup 3}/d, MPY of 0.26 m{sup 3} CH{sub 4}/g COD{sub added}, and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes.

  6. Determinants for the improved thermostability of a mesophilic family 11 xylanase predicted by computational methods

    PubMed Central

    2014-01-01

    Background Xylanases have drawn much attention owing to possessing great potential in various industrial applications. However, the applicability of xylanases, exemplified by the production of bioethanol and xylooligosaccharides (XOSs), was bottlenecked by their low stabilities at higher temperatures. The main purpose of this work was to improve the thermostability of AuXyn11A, a mesophilic glycoside hydrolase (GH) family 11 xylanase from Aspergillus usamii E001, by N-terminus replacement. Results A hybrid xylanase with high thermostability, named AEXynM, was predicted by computational methods, and constructed by substituting the N-terminal 33 amino acids of AuXyn11A with the corresponding 38 ones of EvXyn11TS, a hyperthermostable family 11 xylanase. Two AuXyn11A- and AEXynM-encoding genes, Auxyn11A and AExynM, were then highly expressed in Pichia pastoris GS115, respectively. The specific activities of two recombinant xylanases (reAuXyn11A and reAEXynM) were 10,437 and 9,529 U mg-1. The temperature optimum and stability of reAEXynM reached 70 and 75°C, respectively, much higher than those (50 and 45°C) of reAuXyn11A. The melting temperature (Tm) of reAEXynM, measured using the Protein Thermal Shift (PTS) method, increased by 34.0°C as compared with that of reAuXyn11A. Analyzed by HPLC, xylobiose and xylotriose as the major hydrolytic products were excised from corncob xylan by reAEXynM. Additionally, three single mutant genes from AExynM (AExynMC5T, AExynMP9S, and AExynMH14N) were constructed by site-directed mutagenesis as designed theoretically, and expressed in P. pastoris GS115, respectively. The thermostabilities of three recombinant mutants clearly decreased as compared with that of reAEXynM, which demonstrated that the three amino acids (Cys5, Pro9, and His14) in the replaced N-terminus contributed mainly to the high thermostability of AEXynM. Conclusions This work highly enhanced the thermostability of AuXyn11A by N-terminus replacement, and further verified, by site-directed mutagenesis, that Cys5, Pro9, and His14 contributed mainly to the improved thermostability. It will provide an effective strategy for improving the thermostabilities of other enzymes. PMID:24393334

  7. Presence of aerobic micro-organisms and their influence on basic semen parameters in infertile men.

    PubMed

    Filipiak, E; Marchlewska, K; Oszukowska, E; Walczak-Jedrzejowska, R; Swierczynska-Cieplucha, A; Kula, K; Slowikowska-Hilczer, J

    2015-09-01

    Urogenital tract infections in males are one of the significant etiological factors in infertility. In this prospective study, 72 patients with abnormal semen parameters or any other symptoms of urogenital tract infection were examined. Semen analysis according to the WHO 2010 manual was performed together with microbial assessment: aerobic bacteria culture, Chlamydia antigen test, Candida culture, Ureaplasma and Mycoplasma-specific culture. In total, 69.4% of semen samples were positive for at least one micro-organism. Ureaplasma sp. was the most common micro-organism found in 33% of semen samples of infertile patients with suspected male genital tract infection. The 2nd most common micro-organisms were Enterococcus faecalis (12.5%) and Escherichia coli (12.5%), followed by Staphylococcus aureus (7%), Chlamydia trachomatis (7%) and Candida sp. (5.6%). Generally, bacteria were sensitive to at least one of the antibiotics tested. No statistically significant relationship was observed between the presence of aerobic micro-organisms in semen and basic semen parameters: volume, pH, concentration, total count, motility, vitality and morphology. PMID:25209133

  8. The emission of volatile compounds during the aerobic and the combined anaerobic/aerobic composting of biowaste

    NASA Astrophysics Data System (ADS)

    Smet, Erik; Van Langenhove, Herman; De Bo, Inge

    Two different biowaste composting techniques were compared with regard to their overall emission of volatile compounds during the active composting period. In the aerobic composting process, the biowaste was aerated during a 12-week period, while the combined anaerobic/aerobic composting process consisted of a sequence of a 3-week anaerobic digestion (phase I) and a 2-week aeration period (phase II). While the emission of volatiles during phase I of the combined anaerobic/aerobic composting process was measured in a full-scale composting plant, the aerobic stages of both composting techniques were performed in pilot-scale composting bins. Similar groups of volatile compounds were analysed in the biogas and the aerobic composting waste gases, being alcohols, carbonyl compounds, terpenes, esters, sulphur compounds and ethers. Predominance of alcohols (38% wt/wt of the cumulative emission) was observed in the exhaust air of the aerobic composting process, while predominance of terpenes (87%) and ammonia (93%) was observed in phases I and II of the combined anaerobic/aerobic composting process, respectively. In the aerobic composting process, 2-propanol, ethanol, acetone, limonene and ethyl acetate made up about 82% of the total volatile organic compounds (VOC)-emission. Next to this, the gas analysis during the aerobic composting process revealed a strong difference in emission profile as a function of time between different groups of volatiles. The total emission of VOC, NH 3 and H 2S during the aerobic composting process was 742 g ton -1 biowaste, while the total emission during phases I and II of the combined anaerobic/aerobic composting process was 236 and 44 g ton -1 biowaste, respectively. Taking into consideration the 99% removal efficiency of volatiles upon combustion of the biogas of phase I in the electricity generator, the combined anaerobic/aerobic composting process can be considered as an attractive alternative for aerobic biowaste composting because of its 17 times lower overall emission of the volatiles mentioned.

  9. Aerobic/anoxic post-treatment of anaerobically digested sewage sludge as an alternative to biological nitrogen removal from reject water.

    PubMed

    Morras, Mikel; Dosta, J; García-Heras, J L

    2015-05-01

    Stabilisation and biological nitrogen removal (BNR) of anaerobically digested sewage sludge were studied in a post-aeration reactor at pilot scale working under alternating anoxic-aerobic conditions. Digested sludge came from a two-stage anaerobic digestion (thermophilic + mesophilic). The best post-aerator performance was achieved when working at an HRT of 10 days (4 days aerobic; dissolved oxygen of 1.8 mg L(-1)) and VS content in the feed no lower than 6.7 g L(-1). Free ammonia concentration values in the effluent above 1.5 mg N L(-1) (around 150 mg NH4 (+)-N L(-1) at pH 7) were necessary to promote the BNR over nitrite. Removal efficiencies up to 80 % NH4 (+)-N, 50-55 % total nitrogen and 15-20 % VS were recorded in this study, with no external addition of chemicals. A nitrogen mass balance revealed that the high percent of NH4 (+)-N assimilated in heterotrophic growth was counteracted with that released in ammonification and fermentation, leading to a NH4 (+)-N removal mainly related to biological nitritation/denitritation. PMID:25407727

  10. Impact of nitrite on aerobic phosphorus uptake by poly-phosphate accumulating organisms in enhanced biological phosphorus removal sludges.

    PubMed

    Zeng, Wei; Li, Boxiao; Yang, Yingying; Wang, Xiangdong; Li, Lei; Peng, Yongzhen

    2014-02-01

    Impact of nitrite on aerobic phosphorus (P) uptake of poly-phosphate accumulating organisms (PAOs) in three different enhanced biological phosphorus removal (EBPR) systems was investigated, i.e., the enriched PAOs culture fed with synthetic wastewater, the two lab-scale sequencing batch reactors (SBRs) treating domestic wastewater for nutrient removal through nitrite-pathway nitritation and nitrate-pathway nitrification, respectively. Fluorescence in situ hybridization results showed that PAOs in the three sludges accounted for 72, 7.6 and 6.5% of bacteria, respectively. In the enriched PAOs culture, at free nitrous acid (FNA) concentration of 0.47 × 10(-3) mg HNO?-N/L, aerobic P-uptake and oxidation of intercellular poly-?-hydroxyalkanoates were both inhibited. Denitrifying phosphorus removal under the aerobic conditions was observed, indicating the existence of PAOs using nitrite as electron acceptor in this culture. When the FNA concentration reached 2.25 × 10(-3) mg HNO2-N/L, denitrifying phosphorus removal was also inhibited. And the inhibition ceased once nitrite was exhausted. Corresponding to both SBRs treating domestic wastewater with nitritation and nitrification pathway, nitrite inhibition on aerobic P-uptake by PAOs did not occur even though FNA concentration reached 3 × 10(-3) and 2.13 × 10(-3) mg HNO?-N/L, respectively. Therefore, PAOs taken from different EBPR activated sludges had different tolerance to nitrite. PMID:23771179

  11. Mesophilic and thermophilic anaerobic biodegradability of water hyacinth pre-treated at 80 {sup o}C

    SciTech Connect

    Ferrer, Ivet; Campos, Elena; Flotats, Xavier

    2010-10-15

    Water hyacinth (Eichornia crassipes) is a fast growing aquatic plant which causes environmental problems in continental water bodies. Harvesting and handling this plant becomes an issue, and focus has been put on the research of treatment alternatives. Amongst others, energy production through biomethanation has been proposed. The aim of this study was to assess the anaerobic biodegradability of water hyacinth under mesophilic and thermophilic conditions. The effect of a thermal sludge pre-treatment at 80 {sup o}C was also evaluated. To this end, anaerobic biodegradability tests were carried out at 35 {sup o}C and 55 {sup o}C, with raw and pre-treated water hyacinth. According to the results, the thermal pre-treatment enhanced the solubilisation of water hyacinth (i.e. increase in the soluble to total chemical oxygen demand (COD)) from 4% to 12% after 30 min. However, no significant effect was observed on the methane yields (150-190 L CH{sub 4}/kg volatile solids). Initial methane production rates for thermophilic treatments were two fold those of mesophilic ones (6-6.5 L vs. 3-3.5 L CH{sub 4}/kg COD.day). Thus, higher methane production rates might be expected from thermophilic reactors working at short retention times. The study of longer low temperature pre-treatments or pre-treatments at elevated temperatures coupled to thermophilic reactors should be considered in the future.

  12. Acidogenic fermentation of Scenedesmus sp.-AMDD: Comparison of volatile fatty acids yields between mesophilic and thermophilic conditions.

    PubMed

    Gruhn, Marvin; Frigon, Jean-Claude; Guiot, Serge R

    2016-01-01

    This study compared the acidogenic fermentation of Scenedesmus sp.-AMDD at laboratory-scale, under mesophilic (35°C) and thermophilic conditions (55°C). Preliminary batch tests were performed to evaluate best conditions for volatile fatty acid (VFA) production from microalgal biomass, with respect to the inoculum, pH and nutrients. The use of bovine manure as inoculum, the operating pH of 4.5 and the addition of a nutrient mix, resulted in a high VFA production of up to 222mgg(-1) total volatile solid (TVS), with a butyrate share of 27%. Both digesters displayed similar hydrolytic activity with 0.38±0.02 and 0.42±0.03 g soluble chemical oxygen demand (COD)g(-1) TVS for the digesters operated at 35 and 55°C, respectively. Mesophilic conditions were more favorable for VFA production, which reached 171±5, compared to 88±12 mg soluble CODg(-1) TVS added under thermophilic conditions (94% more). It was shown that in both digesters, butyrate was the predominant VFA. PMID:26551650

  13. Sustainable organic loading rate and energy recovery potential of mesophilic anaerobic membrane bioreactor for municipal wastewater treatment.

    PubMed

    Wei, Chun-Hai; Harb, Moustapha; Amy, Gary; Hong, Pei-Ying; Leiknes, TorOve

    2014-08-01

    The overall performance of a mesophilic anaerobic membrane bioreactor (AnMBR) for synthetic municipal wastewater treatment was investigated under a range of organic loading rate (OLR). A very steady and high chemical oxygen demand (COD) removal (around 98%) was achieved over a broad range of volumetric OLR of 0.8-10 gCOD/L/d. The sustainable volumetric and sludge OLR satisfying a permeate COD below 50 mg/L for general reuse was 6 gCOD/L/d and 0.63 gCOD/gMLVSS (mixed liquor volatile suspended solids)/d, respectively. At a high sludge OLR of over 0.6 gCOD/gMLVSS/d, the AnMBR achieved high methane production of over 300 ml/gCOD (even approaching the theoretical value of 382 ml/gCOD). A low biomass production of 0.015-0.026 gMLVSS/gCOD and a sustainable flux of 6L/m(2)/h were observed. The integration of a heat pump and forward osmosis into the mesophilic AnMBR process would be a promising way for net energy recovery from typical municipal wastewater in a temperate area. PMID:24926606

  14. The green non-sulfur bacteria: a deep branching in the eubacterial line of descent

    NASA Technical Reports Server (NTRS)

    Oyaizu, H.; Debrunner-Vossbrinck, B.; Mandelco, L.; Studier, J. A.; Woese, C. R.

    1987-01-01

    Ribosomal RNA sequence comparisons define a phylogenetic grouping, the green non-sulfur bacteria and relatives (GNS), known to contain the genera Chloroflexus, Herpetosiphon and Thermomicrobium--organisms that have little phenotypic similarity. The unit is phylogenetically deep, but entirely distinct from any other eubacterial division (phylum). It is also relatively ancient--branching from the common eubacterial stem earlier than any other group of eubacteria reported thus far. The group phenotype is predominantly thermophilic, and its thermophilic members, especially Thermomicrobium, are more slowly evolving than Herpetosiphon, a mesophile. The GNS unit appears significantly older than either the green sulfur bacteria or the cyanobacteria--making it likely that organisms such as Chloroflexus, not the cyanobacteria, generated the oldest stromatolites, which formed over three billion years ago.

  15. Biodegradation of Triclosan by Aerobic Microorganisms 

    E-print Network

    Lee, Do Gyun

    2012-10-19

    biodegradation by strain KCY1. By using [13C12]-triclosan stable isotope probing, eleven uncultured triclosan-utilizing bacteria in a triclosan-degrading microbial consortium were identified. These clones are distributed among alpha-, beta-, or gamma...

  16. Biotransformation of phytosterols under aerobic conditions.

    PubMed

    Dykstra, Christy M; Giles, Hamilton D; Banerjee, Sujit; Pavlostathis, Spyros G

    2014-07-01

    Phytosterols are plant-derived sterols present in pulp and paper wastewater and have been implicated in the endocrine disruption of aquatic species. Bioassays were performed to assess the effect of an additional carbon source and/or solubilizing agent on the aerobic biotransformation of a mixture of three common phytosterols (?-sitosterol, stigmasterol and campesterol). The aerobic biotransformation of the phytosterol mixture by a mixed culture developed from a pulp and paper wastewater treatment system was examined under three separate conditions: with phytosterols as the sole added carbon source, with phytosterols and dextrin as an additional carbon source, and with phytosterols added with ethanol as an additional carbon source and solubilizing agent. Significant phytosterol removal was not observed in assays set up with phytosterol powder, either with or without an additional carbon source. In contrast, all three phytosterols were aerobically degraded when added as a dissolved solution in ethanol. Thus, under the experimental conditions of this study, the bioavailability of phytosterols was limited without the presence of a solubilizing agent. The total phytosterol removal rate was linear for the first six days before re-spiking, with a rate of 0.47 mg/L-d (R(2) = 0.998). After the second spiking, the total phytosterol removal rate was linear for seven days, with a rate of 0.32 mg/L-d (R(2) = 0.968). Following the 7th day, the phytosterol removal rate markedly accelerated, suggesting two different mechanisms are involved in phytosterol biotransformation, more likely related to the production of enzyme(s) involved in phytosterol degradation, induced under different cell growth conditions. ?-sitosterol was preferentially degraded, as compared to stigmasterol and campesterol, although all three phytosterols fell below detection limits by the 24th day of incubation. PMID:24747138

  17. Nitrogen Removal over Nitrite by Aeration Control in Aerobic Granular Sludge Sequencing Batch Reactors

    PubMed Central

    Lochmatter, Samuel; Maillard, Julien; Holliger, Christof

    2014-01-01

    This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m?3·d?1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria. PMID:25006970

  18. Nitrogen removal over nitrite by aeration control in aerobic granular sludge sequencing batch reactors.

    PubMed

    Lochmatter, Samuel; Maillard, Julien; Holliger, Christof

    2014-07-01

    This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m-3·d-1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria. PMID:25006970

  19. Phosphorus release in aerobic sludge digestion.

    PubMed

    Ju, Lu-Kwang; Shah, Hemant K; Porteous, Jim

    2005-01-01

    The objectives of this study are to examine the phosphorus release in aerobic sludge digestion and to better understand its governing mechanisms. In this study, phosphorus release was examined using the secondary sludge from both conventional and biological nutrient removal processes. The experiments were carried out at room temperature (22 +/- 2 degrees C), with or without automatic control of pH (4.5 to 7.8), and under three aeration schemes: fully aerobic (dissolved oxygen [DO] at 3 to 4 mg/L), low DO (0.2 to 0.8 mg/L), and cyclic (with alternate on/off aeration). The released phosphorus concentrations were 20 to 80 mg/L for the conventional sludge and 60 to 130 mg/L for the biophosphorus sludge. Higher phosphorus release also occurred at low pH (<6.0). As for the effect of DO, fully aerobic digestion caused higher phosphorus release than the low-DO and cyclic operations. For better understanding, the solid phosphorus in sludge was conceptually categorized into three forms: inorganic phosphorus precipitates, organic cellular phosphorus, and polyphosphate (poly-P) in polyphosphate-accumulating organisms. Dissolution of inorganic phosphorus precipitates is controlled by physical and chemical conditions, with pH being the most important in this study. Lowering the pH to 4 to 6 clearly promoted the release of inorganic phosphorus. Polyphosphate hydrolysis, on the other hand, was found to be regulated biologically (sensitive to occurrence of anaerobic conditions) and was insignificant in the glutaraldehyde-fixed sludge. Phosphorus release from organic phosphorus should correlate with the volatile solid (VS) digestion, which lyses the cells and frees the phosphorus covalently bonded with the organic matters. The amounts of phosphorus released per unit VS digested (deltaP/deltaVS) were therefore calculated for experiments with long periods of constant pH (to minimize interferences from dissolution/precipitation of inorganic phosphorus). The results suggested that some poly-P was hydrolyzed and released accompanying the aerobic VS digestion, but at rates far lower than those under anaerobic conditions. PMID:16274090

  20. Upper limb aerobic training improves aerobic fitness and all-out performance of America's Cup grinders.

    PubMed

    Adami, Paolo Emilio; Delussu, Anna Sofia; Rodio, Angelo; Squeo, Maria Rosaria; Corsi, Loretta; Quattrini, Filippo Maria; Fattorini, Luigi; Bernardi, Marco

    2015-01-01

    This research on "America's Cup" grinders investigated the effects of a specific eight-week long-arm cranking ergometer (ACE) training on upper body (UB) aerobic fitness (ventilatory threshold - Tvent, respiratory compensation point- RCP, -oxygen uptake peak - VO?peak) and high intensity working capacity. The training consisted of sessions carried out for 20-30 mins, three times per week, at an intensity between the UB-Tvent and UB-RCP, and replaced part of a typical lower limb aerobic training whilst maintaining the usual weekly schedule of callisthenics, resistance training and sailing. Seven sailors, including four grinders and three mastmen (age 30 ± 5.5 years, height 1.9 ± 0.04 m, body mass 102 ± 3.6 kg), were evaluated through both an ACE cardiopulmonary maximal exercise test (CPET) and an ACE all-out up to exhaustion exercise test, before and after the ACE training. UB aerobic fitness improved significantly: UB-VO?peak increased from 4.29 ± 0.442 to 4.52 ± 0.522 l·min(-1) (6.4 ± 3.66%), VO? at UB-Tvent from 2.42 ± 0.282 to 2.97 ± 0.328 l·min(-1) (22.8 ± 5.09%) and VO? at UB-RCP from 3.25 ± 0.402 to 3.75 ± 0.352 l·min(-1) (16.1 ± 10.83%). Peak power at the ACE CPET increased from 351 ± 27.5 to 387 ± 33.5 W (10.5 ± 6.93%). The all-out test total mechanical work increased from 28.9 ± 2.35 to 40.1 ± 3.76 kJ (72.1 ± 4.67%). In conclusion, a high intensity aerobic ACE training can be effective in improving grinding performance by increasing UB aerobic fitness and all-out working capacity. PMID:25357134

  1. Genomics of Probiotic Bacteria

    NASA Astrophysics Data System (ADS)

    O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

    Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

  2. Functional diversity of bacteria in a ferruginous hydrothermal sediment.

    PubMed

    Handley, Kim M; Boothman, Christopher; Mills, Rachel A; Pancost, Richard D; Lloyd, Jonathan R

    2010-09-01

    A microbial community showing diverse respiratory processes was identified within an arsenic-rich, ferruginous shallow marine hydrothermal sediment (20-40 degrees C, pH 6.0-6.3) in Santorini, Greece. Analyses showed that ferric iron reduction with depth was broadly accompanied by manganese and arsenic reduction and FeS accumulation. Clone library analyses indicated the suboxic-anoxic transition zone sediment contained abundant Fe(III)- and sulfate-reducing Deltaproteobacteria, whereas the overlying surface sediment was dominated by clones related to the Fe(II)-oxidizing zetaproteobacterium, Mariprofundus ferroxydans. Cultures obtained from the transition zone were enriched in bacteria that reduced Fe(III), nitrate, sulfate and As(V) using acetate or lactate as electron donors. In the absence of added organic carbon, bacteria were enriched that oxidized Fe(II) anaerobically or microaerobically, sulfide microaerobically and aerobically and As(III) aerobically. According to 16S rRNA gene analyses, enriched bacteria represented a phylogenetically wide distribution. Most probable number counts indicated an abundance of nitrate-, As(V)- and Fe(III)((s,aq))-reducers, and dissolved sulfide-oxidizers over sulfate-reducers, and FeS-, As(III)- and nitrate-dependent Fe(II)-oxidisers in the transition zone. It is noteworthy that the combined community and geochemical data imply near-surface microbial iron and arsenic redox cycling were dominant biogeochemical processes. PMID:20410934

  3. Effect of low-dose radiation on microbiological, chemical, and sensory characteristics of chicken meat stored aerobically at 4 degrees C.

    PubMed

    Balamatsia, Christiana C; Rogga, Kondylia; Badeka, Anastasia; Kontominas, Michael G; Savvaidis, Ioannis N

    2006-05-01

    The effect of gamma-radiation (0.5, 1, and 2 kGy) on the shelf life of fresh skinless chicken breast fillets stored aerobically at 4 degrees C was evaluated. Microbiological, chemical, and sensorial changes occurring in chicken samples were monitored for 21 days. Irradiation reduced populations of bacteria, i.e., total viable bacteria, Brochothrix thermosphacta, lactic acid bacteria (LAB), and the effect was more pronounced at the highest dose (2 kGy). Pseudomonads, yeasts and molds, and Enterobacteriaceae were highly sensitive to gamma-radiation and were completely eliminated at all doses. Of the chemical indicators of spoilage, thiobarbituric values for nonirradiated and irradiated aerobically packaged chicken samples were in general low (<1 mg of malonaldehyde per kg of muscle) during refrigerated storage for 21 days. With regard to volatile amines, both trimethylamine nitrogen (TMA-N) and total volatile basic nitrogen (TVB-N) values for nonirradiated aerobically packaged chicken increased steeply, with final values of ca. 20.3 and 58.5 mg N/100 g of muscle, respectively. Irradiated aerobically packaged chicken samples had significantly lower TMA-N and TVB-N values (P < 0.05) of ca. 2.2 to 3.6 and 30.5 to 37.1 mg N/100 g of muscle, respectively, during refrigerated storage for 21 days. Of the biogenic amines monitored, only putrescine and cadaverine were detected in significant concentrations in both nonirradiated and irradiated chicken samples, whereas histamine formation was noted only in nonirradiated samples throughout storage. On the basis of sensorial evaluation, low-dose irradiation (0.5 and 1.0 kGy) in combination with aerobic packaging extended the shelf life of fresh chicken fillets by ca. 4 to 5 days, whereas irradiation at 2.0 kGy extended the shelf life by more than 15 days compared with that of nonirradiated chicken. PMID:16715814

  4. Quantitative proteomics and transcriptomics of anaerobic and aerobic yeast cultures reveals post-

    E-print Network

    Shmulevich, Ilya

    Quantitative proteomics and transcriptomics of anaerobic and aerobic yeast cultures reveals post was investigated using metabolic stable-isotope labelling in aerobic and anaerobic glucose-limited chemostat, probability density function; RAnae : Ae, relative protein ratios (anaerobic : aerobic); RMS, root

  5. Methylobacterium populi sp. nov., a novel aerobic, pink-pigmented, facultatively

    E-print Network

    Doty, Sharon Lafferty

    Methylobacterium populi sp. nov., a novel aerobic, pink-pigmented, facultatively methylotrophic, University of Washington, Seattle, WA 98195, USA A pink-pigmented, aerobic, facultatively methylotrophicT =NCIMB 13946T ). Species of the genus Methylobacterium are strictly aerobic, facultatively

  6. Palladium Catalyzed Aerobic Dehydrogenation: From Alcohols to Indoles and Asymmetric Catalysis

    E-print Network

    Stoltz, Brian M.

    Palladium Catalyzed Aerobic Dehydrogenation: From Alcohols to Indoles and Asymmetric Catalysis Brian M. Stoltz (Received February 12, 2004; CL-048001) Abstract Catalytic aerobic dehydrogenation- posed to asymmetric induction). Recently, increasing interest in the use of palladium catalyzed aerobic

  7. The Resolution of Important Pharmaceutical Building Blocks by Palladium-Catalyzed Aerobic Oxidation of Secondary Alcohols

    E-print Network

    Stoltz, Brian M.

    The Resolution of Important Pharmaceutical Building Blocks by Palladium-Catalyzed Aerobic Oxidation. Abstract: The palladium-catalyzed aerobic oxidative kinetic resolution of key pharmaceutical building selective aerobic oxidative kinetic resolu- tion yet described. Keywords: asymmetric catalysis; kinetic

  8. Aerobic treatment of wine-distillery wastewaters

    SciTech Connect

    Sales, D.; Valcarcel, M.J.; Perez, L.; de la Ossa, E.M.

    1987-01-01

    Waste from food-processing and allied industries is largely made up of organic compounds which can be metabolized by aerobic or anaerobic means. However, these wastes present a series of problems to biological depuration plants, such as the need for prior treatment to establish conditions suitable for the development of the microorganisms responsible for the process; and the long retention time of the biomass if acceptable effluents are to be obtained. Again, the seasonal nature of many of these industries makes for very heterogeneous waste. This means that treatment plant must be versatile and are subject to rapid successions of close-down and start-up interspersed with long intervals of inactivity. All these difficulties oblige the industries in the sector to adapt depurative technology to their particular needs. Wine distilleries fall into this general category. Their waste (called vinasses) is acidic, has a high organic content and varies widely according to the raw matter distilled: wine, lies, etc. This paper studies the start-up of digestors for aerobic treatment of vinasses and the establishment of optimum operating conditions for an adequate depurative performance.

  9. Characterization and aerobic biodegradation of selected monoterpenes

    SciTech Connect

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M.

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  10. Effects of Immersion Chilling Using Different Volumes of Water on Bacteria Recovery From Broiler Carcasses and Chiller Water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During a previous experiment, we investigated the microbiological impact of using a low (2.1 L/kg) or a high volume (16.8 L/kg) of non-chlorinated water to immersion chill broiler carcasses. From that study, it was concluded that the low volume of water removed fewer total aerobic bacteria, E. coli,...

  11. Methane-Derived Hydrogen in Lipids Produced by Aerobic Methanotrophs

    NASA Astrophysics Data System (ADS)

    Sessions, A. L.; Jahnke, L. L.; Schimmelmann, A.; Hayes, J. M.

    2001-12-01

    Combined hydrogen- and carbon-isotopic analyses of methane often provide important clues about its origin. Unfortunately, methane is not preserved in the geologic record so these analyses can only examine trapped or actively produced methane. The lipids of microorganisms that consume methane potentially record its isotopic composition, and are accessible throughout most of the geologic record. Those lipids therefore represent a potential means for examining the characteristics of methane released into the oceans over geologic history. We have examined the hydrogen-isotopic relationships between methane and lipids in the aerobic methanotroph Methylococcus capsulatus using cultures in which the D/H ratio of supplied water and methane were controlled independently. Resulting ? D values were measured for a range of fatty acids, sterols, and hopanols using isotope-ratio-monitoring gas chromatography/mass spectrometry. We estimate that 31 +/- 2% of hydrogen in every lipid we examined is derived from methane, regardless of whether cultures were harvested in exponential or stationary phase. The biochemical pathways responsible for the transfer of hydrogen from methane to lipids are not fully understood. Isotope fractionation associated with the utilization of methane (i.e., ? lipid/methane) averages 0.986 for fatty acids and 0.789 for isoprenoid lipids. For water, fractionation (? lipid/water) averages 0.938 for fatty acids and 0.831 for isoprenoid lipids. Given typical ? D values for seawater (0%) and thermogenic `dry' methane (-150‰ ), fatty acids from M. capsulatus should have ? D values near -95‰ , and isoprenoids should have ? D values near -215‰ . Using ? Dmethane = -300‰ , a value near the lower limit of those for biogenic methanes, we predict ? D values for methanotroph fatty acids and isoprenoid lipids of -140 and -260‰ , respectively. It appears possible that D/H measurements of lipids from methanotrophic bacteria will provide useful hydrogen-isotopic information about methane that has been entirely consumed.

  12. Interaction of Cadmium With the Aerobic Bacterium Pseudomonas Mendocina

    NASA Astrophysics Data System (ADS)

    Schramm, P. J.; Haack, E. A.; Maurice, P. A.

    2006-05-01

    The fate of toxic metals in the environment can be heavily influenced by interaction with bacteria in the vadose zone. This research focuses on the interactions of cadmium with the strict aerobe Pseudomonas mendocina. P. mendocina is a gram-negative bacterium that has shown potential in the bioremediation of recalcitrant organic compounds. Cadmium is a common environmental contaminant of wide-spread ecological consequence. In batch experiments P. mendocina shows typical bacterial growth curves, with an initial lag phase followed by an exponential phase and a stationary to death phase; concomitant with growth was an increase in pH from initial values of 7 to final values at 96 hours of 8.8. Cd both delays the onset of the exponential phase and decreases the maximum population size, as quantified by optical density and microscopic cell counts (DAPI). The total amount of Cd removed from solution increases over time, as does the amount of Cd removed from solution normalized per bacterial cell. Images obtained with transmission electron microscopy (TEM) showed the production of a cadmium, phosphorus, and iron containing precipitate that was similar in form and composition to precipitates formed abiotically at elevated pH. However, by late stationary phase, the precipitate had been re-dissolved, perhaps by biotic processes in order to obtain Fe. Stressed conditions are suggested by TEM images showing the formation of pili, or nanowires, when 20ppm Cd was present and a marked decrease in exopolysaccharide and biofilm material in comparison to control cells (no cadmium added).

  13. Aerobic Digestion. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Klopping, Paul H.

    This manual contains the textual material for a single-lesson unit on aerobic sludge digestion. Topic areas addressed include: (1) theory of aerobic digestion; (2) system components; (3) performance factors; (4) indicators of stable operation; and (5) operational problems and their solutions. A list of objectives, glossary of key terms, and…

  14. The Acute Effect of Aerobic Exercise on Measures of Stress.

    ERIC Educational Resources Information Center

    Fort, Inza L.; And Others

    The immediate response of stress to aerobic exercise was measured by utilizing the Palmar Sweat Index (PSI) and the State-Trait Anxiety Inventory (STAI). Forty subjects (20 male and 20 female) from the ages of 18-30 sustained a single bout of aerobic activity for 30 minutes at 60 percent of their maximum heart rate. Pre-treatment procedures…

  15. Aerobic Fitness Thresholds Associated with Fifth Grade Academic Achievement

    ERIC Educational Resources Information Center

    Wittberg, Richard; Cottrell, Lesley A.; Davis, Catherine L.; Northrup, Karen L.

    2010-01-01

    Background: Whereas effects of physical fitness and physical activity on cognitive function have been documented, little is known about how they are related. Purpose: This study assessed student aerobic fitness measured by FITNESSGRAM Mile times and/or Pacer circuits and whether the nature of the association between aerobic fitness and…

  16. Inhibition of aerobic respiration and dissimilatory perchlorate reduction using cyanide

    E-print Network

    Inhibition of aerobic respiration and dissimilatory perchlorate reduction using cyanide Yanguang reduction and aerobic respiration was examined using pure cultures of Azospira sp. KJ. Cyanide reduction; Respiration pathway 1. Introduction Perchlorate (ClOÀ 4 ) has been detected in impacted ground

  17. Digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage.

    PubMed

    Ghasimi, Dara S M; Tao, Yu; de Kreuk, Merle; Abbas, Ben; Zandvoort, Marcel H; van Lier, Jules B

    2015-12-15

    This study investigates the start-up and operation of bench-scale mesophilic (35 °C) and thermophilic (55 °C) anaerobic sequencing batch reactor (SBR) digesters treating the fine sieved fraction (FSF) from raw municipal sewage. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter equipped with a 350 micron mesh. For the given wastewater, the major component of FSF was toilet paper, which is estimated to be 10-14 kg per year per average person in the western European countries. A seven months adaptation time was allowed for the thermophilic and mesophilic digesters in order to adapt to FSF as the sole substrate with varying dry solids content of 10-25%. Different SBR cycle durations (14, 9 and 2 days) were applied for both temperature conditions to study methane production rates, volatile fatty acids (VFAs) dynamics, lag phases, as well as changes in microbial communities. The prevailing sludge in the two digesters consisted of very different bacterial and archaeal communities, with OP9 lineage and Methanothermobacter being pre-dominant in the thermophilic digester and Bacteroides and Methanosaeta dominating the mesophilic one. Eventually, decreasing the SBR cycle period, thus increasing the FSF load, resulted in improved digester performances, particularly with regard to the thermophilic digester, i.e. shortened lag phases following the batch feedings, and reduced VFA peaks. Over time, the thermophilic digester outperformed the mesophilic one with 15% increased volatile solids (VS) destruction, irrespective to lower species diversity found at high temperature. PMID:25976021

  18. Bacteria turn tiny gears

    SciTech Connect

    2009-01-01

    Swarms of bacteria turn two 380-micron long gears, opening the possibility of building hybrid biological machines at the microscopic scale. Read more at Wired: http://www.wired.com/wiredscience/2009/12/bacterial-micro-machine/#more-15684 or Scientific American: http://www.scientificamerican.com/article.cfm?id=brownian-motion-bacteria

  19. Bleach vs. Bacteria

    MedlinePLUS

    ... Inside Life Science > Bleach vs. Bacteria Inside Life Science View All Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds ... For Proteins, Form Shapes Function This Inside Life Science article also appears on LiveScience . Learn about related ...

  20. The backbone structure of the thermophilic Thermoanaerobacter tengcongensis ribose binding protein is essentially identical to its mesophilic E. coli homolog

    SciTech Connect

    Cuneo, Matthew J.; Tian, Yaji; Allert, Malin; Hellinga, Homme W.

    2008-10-27

    We report the X-ray crystal structure of a Thermoanaerobacter tengcongensis ribose binding protein (tteRBP) determined to 1.9 {angstrom} resolution. We find that tteRBP is significantly more stable ({sup app}T{sub m} value {approx} 102 C) than the mesophilic Escherichia coli ribose binding protein (ecRBP) ({sup app}T{sub m} value {approx} 56 C). The tteRBP has essentially the identical backbone conformation (0.41 {angstrom} RMSD of 235/271 C{sub {alpha}} positions and 0.65 {angstrom} RMSD of 270/271 C{sub {alpha}} positions) as ecRBP. Classification of the amino acid substitutions as a function of structure therefore allows the identification of amino acids which potentially contribute to the observed thermal stability of tteRBP in the absence of large structural heterogeneities.

  1. The fish myotome is composed of both aerobic and anaerobic muscle. The aerobic or red muscle is used to power

    E-print Network

    Coughlin, David J.

    409 The fish myotome is composed of both aerobic and anaerobic muscle. The aerobic or red muscle of their red muscle. These patterns are associated with differences in body bending kinematics (Coughlin, 2002 with different anterior- posterior patterns of muscle contraction kinetics (Coughlin, 2002). For instance

  2. Acetic acid bacteria: A group of bacteria with versatile biotechnological applications.

    PubMed

    Saichana, Natsaran; Matsushita, Kazunobu; Adachi, Osao; Frébort, Ivo; Frebortova, Jitka

    2015-11-01

    Acetic acid bacteria are gram-negative obligate aerobic bacteria assigned to the family Acetobacteraceae of Alphaproteobacteria. They are members of the genera Acetobacter, Gluconobacter, Gluconacetobacter, Acidomonas, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia, Granulibacter, Tanticharoenia, Ameyamaea, Neokomagataea, and Komagataeibacter. Many strains of Acetobacter and Komagataeibacter have been known to possess high acetic acid fermentation ability as well as the acetic acid and ethanol resistance, which are considered to be useful features for industrial production of acetic acid and vinegar, the commercial product. On the other hand, Gluconobacter strains have the ability to perform oxidative fermentation of various sugars, sugar alcohols, and sugar acids leading to the formation of several valuable products. Thermotolerant strains of acetic acid bacteria were isolated in order to serve as the new strains of choice for industrial fermentations, in which the cooling costs for maintaining optimum growth and production temperature in the fermentation vessels could be significantly reduced. Genetic modifications by adaptation and genetic engineering were also applied to improve their properties, such as productivity and heat resistance. PMID:25485864

  3. Progressive degradation of crude oil n-alkanes coupled to methane production under mesophilic and thermophilic conditions.

    PubMed

    Cheng, Lei; Shi, Shengbao; Li, Qiang; Chen, Jianfa; Zhang, Hui; Lu, Yahai

    2014-01-01

    Although methanogenic degradation of hydrocarbons has become a well-known process, little is known about which crude oil tend to be degraded at different temperatures and how the microbial community is responded. In this study, we assessed the methanogenic crude oil degradation capacity of oily sludge microbes enriched from the Shengli oilfield under mesophilic and thermophilic conditions. The microbial communities were investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes combined with cloning and sequencing. Enrichment incubation demonstrated the microbial oxidation of crude oil coupled to methane production at 35 and 55°C, which generated 3.7±0.3 and 2.8±0.3 mmol of methane per gram oil, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that crude oil n-alkanes were obviously degraded, and high molecular weight n-alkanes were preferentially removed over relatively shorter-chain n-alkanes. Phylogenetic analysis revealed the concurrence of acetoclastic Methanosaeta and hydrogenotrophic methanogens but different methanogenic community structures under the two temperature conditions. Candidate divisions of JS1 and WWE 1, Proteobacteria (mainly consisting of Syntrophaceae, Desulfobacteraceae and Syntrophorhabdus) and Firmicutes (mainly consisting of Desulfotomaculum) were supposed to be involved with n-alkane degradation in the mesophilic conditions. By contrast, the different bacterial phylotypes affiliated with Caldisericales, "Shengli Cluster" and Synergistetes dominated the thermophilic consortium, which was most likely to be associated with thermophilic crude oil degradation. This study revealed that the oily sludge in Shengli oilfield harbors diverse uncultured microbes with great potential in methanogenic crude oil degradation over a wide temperature range, which extend our previous understanding of methanogenic degradation of crude oil alkanes. PMID:25409013

  4. Progressive Degradation of Crude Oil n-Alkanes Coupled to Methane Production under Mesophilic and Thermophilic Conditions

    PubMed Central

    Cheng, Lei; Shi, Shengbao; Li, Qiang; Chen, Jianfa; Zhang, Hui; Lu, Yahai

    2014-01-01

    Although methanogenic degradation of hydrocarbons has become a well-known process, little is known about which crude oil tend to be degraded at different temperatures and how the microbial community is responded. In this study, we assessed the methanogenic crude oil degradation capacity of oily sludge microbes enriched from the Shengli oilfield under mesophilic and thermophilic conditions. The microbial communities were investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes combined with cloning and sequencing. Enrichment incubation demonstrated the microbial oxidation of crude oil coupled to methane production at 35 and 55°C, which generated 3.7±0.3 and 2.8±0.3 mmol of methane per gram oil, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that crude oil n-alkanes were obviously degraded, and high molecular weight n-alkanes were preferentially removed over relatively shorter-chain n-alkanes. Phylogenetic analysis revealed the concurrence of acetoclastic Methanosaeta and hydrogenotrophic methanogens but different methanogenic community structures under the two temperature conditions. Candidate divisions of JS1 and WWE 1, Proteobacteria (mainly consisting of Syntrophaceae, Desulfobacteraceae and Syntrophorhabdus) and Firmicutes (mainly consisting of Desulfotomaculum) were supposed to be involved with n-alkane degradation in the mesophilic conditions. By contrast, the different bacterial phylotypes affiliated with Caldisericales, “Shengli Cluster” and Synergistetes dominated the thermophilic consortium, which was most likely to be associated with thermophilic crude oil degradation. This study revealed that the oily sludge in Shengli oilfield harbors diverse uncultured microbes with great potential in methanogenic crude oil degradation over a wide temperature range, which extend our previous understanding of methanogenic degradation of crude oil alkanes. PMID:25409013

  5. Magnesium carbonate precipitate strengthened aerobic granules.

    PubMed

    Lee, Duu-Jong; Chen, Yu-You

    2015-05-01

    Aerobic granules were precipitated internally with magnesium carbonate to enhance their structural stability under shear. The strengthened granules were tested in continuous-flow reactors for 220 days at organic loadings of 6-39 kg/m(3)/day, hydraulic retention times of 0.44-19 h, and temperatures of 10 or 28°C. The carbonate salt had markedly improved the granule strength without significant changes in granule morphology or microbial communities (with persistent strains Streptomyces sp., Rhizobium sp., Brevundimonas sp., and Nitratireductor sp.), or sacrifice in biological activity for organic degradation. MgCO3 precipitated granules could be used in continuous-flow reactor for wastewater treatment at low cost and with easy processing efforts. PMID:25727761

  6. Surface Structure of Aerobically Oxidized Diamond Nanocrystals

    PubMed Central

    2015-01-01

    We investigate the aerobic oxidation of high-pressure, high-temperature nanodiamonds (5–50 nm dimensions) using a combination of carbon and oxygen K-edge X-ray absorption, wavelength-dependent X-ray photoelectron, and vibrational spectroscopies. Oxidation at 575 °C for 2 h eliminates graphitic carbon contamination (>98%) and produces nanocrystals with hydroxyl functionalized surfaces as well as a minor component (<5%) of carboxylic anhydrides. The low graphitic carbon content and the high crystallinity of HPHT are evident from Raman spectra acquired using visible wavelength excitation (?excit = 633 nm) as well as carbon K-edge X-ray absorption spectra where the signature of a core–hole exciton is observed. Both spectroscopic features are similar to those of chemical vapor deposited (CVD) diamond but differ significantly from the spectra of detonation nanodiamond. The importance of these findings to the functionalization of nanodiamond surfaces for biological labeling applications is discussed. PMID:25436035

  7. Surface Structure of Aerobically Oxidized Diamond Nanocrystals.

    PubMed

    Wolcott, Abraham; Schiros, Theanne; Trusheim, Matthew E; Chen, Edward H; Nordlund, Dennis; Diaz, Rosa E; Gaathon, Ophir; Englund, Dirk; Owen, Jonathan S

    2014-11-20

    We investigate the aerobic oxidation of high-pressure, high-temperature nanodiamonds (5-50 nm dimensions) using a combination of carbon and oxygen K-edge X-ray absorption, wavelength-dependent X-ray photoelectron, and vibrational spectroscopies. Oxidation at 575 °C for 2 h eliminates graphitic carbon contamination (>98%) and produces nanocrystals with hydroxyl functionalized surfaces as well as a minor component (<5%) of carboxylic anhydrides. The low graphitic carbon content and the high crystallinity of HPHT are evident from Raman spectra acquired using visible wavelength excitation (?excit = 633 nm) as well as carbon K-edge X-ray absorption spectra where the signature of a core-hole exciton is observed. Both spectroscopic features are similar to those of chemical vapor deposited (CVD) diamond but differ significantly from the spectra of detonation nanodiamond. The importance of these findings to the functionalization of nanodiamond surfaces for biological labeling applications is discussed. PMID:25436035

  8. A distinct pathway for tetrahymanol synthesis in bacteria.

    PubMed

    Banta, Amy B; Wei, Jeremy H; Welander, Paula V

    2015-11-01

    Tetrahymanol is a polycyclic triterpenoid lipid first discovered in the ciliate Tetrahymena pyriformis whose potential diagenetic product, gammacerane, is often used as a biomarker for water column stratification in ancient ecosystems. Bacteria are also a potential source of tetrahymanol, but neither the distribution of this lipid in extant bacteria nor the significance of bacterial tetrahymanol synthesis for interpreting gammacerane biosignatures is known. Here we couple comparative genomics with genetic and lipid analyses to link a protein of unknown function to tetrahymanol synthesis in bacteria. This tetrahymanol synthase (Ths) is found in a variety of bacterial genomes, including aerobic methanotrophs, nitrite-oxidizers, and sulfate-reducers, and in a subset of aquatic and terrestrial metagenomes. Thus, the potential to produce tetrahymanol is more widespread in the bacterial domain than previously thought. However, Ths is not encoded in any eukaryotic genomes, nor is it homologous to eukaryotic squalene-tetrahymanol cyclase, which catalyzes the cyclization of squalene directly to tetrahymanol. Rather, heterologous expression studies suggest that bacteria couple the cyclization of squalene to a hopene molecule by squalene-hopene cyclase with a subsequent Ths-dependent ring expansion to form tetrahymanol. Thus, bacteria and eukaryotes have evolved distinct biochemical mechanisms for producing tetrahymanol. PMID:26483502

  9. Protection of probiotic bacteria in a synbiotic matrix following aerobic storage at 4 deg C

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The survival of single strains of Bifidobacterium breve, Bifidobacterium longum, Lactobacillus acidophilus, and Lactobacillus reuteri was investigated in synbiotics that included 10 mg/mL of fructo-oligosaccharides, inulin and pectic-oligosaccharides in an alginate matrix under refrigerated (4 C) ae...

  10. Survival of Fastidious and Nonfastidious Aerobic Bacteria in Three Bacterial Transport Swab Systems?

    PubMed Central

    Rishmawi, Nabeel; Ghneim, Raed; Kattan, Randa; Ghneim, Riyad; Zoughbi, Madeleine; Abu-Diab, Afaf; Turkuman, Sultan; Dauodi, Rula; Shomali, Issa; Issa, Abed El-Razeq; Siriani, Issa; Marzouka, Hiyam; Schmid, Irmgard; Hindiyeh, Musa Y.

    2007-01-01

    In the present study, we followed the CLSI procedure M40-A to evaluate three specimen transport systems [the new BD CultureSwab MaxV(+), the new Remel BactiSwab, and the Medical Wire & Equipment Transwab] for the survival of fastidious and nonfastidious organisms for 0, 6, 24, and 48 h at room temperature. BD CultureSwab MaxV(+) outperformed the other two swabs for the recovery of the three fastidious organisms, Haemophilus influenzae, Neisseria gonorrhoeae, and Neisseria meningitidis for up to 48 h. Indeed, BD CultureSwab MaxV(+) maintained a constant number of viable H. influenzae and N. meningitidis for up to 48 h, and only a 2 log reduction was noted for N. gonorrhoeae, fulfilling the requirements of M40-A guidelines. However, unlike Remel BactiSwab and the Medical Wire & Equipment Transwab, which fulfilled the M40-A requirements for maintaining the viability of Streptococcus pneumoniae, BD CultureSwab MaxV(+) could not maintain the viability of S. pneumoniae reference or clinical strains past 6 h. Excellent overall sensitivity (98%) (95% confidence interval, 89.5 to 99.7) was observed when the BD CultureSwab MaxV(+) rectal swabs were compared to the “gold standard” stool cultures. Thus, the BD CultureSwab MaxV(+) rectal swab can be used when investigating gastrointestinal bacterial outbreaks or when health care providers face difficulties in obtaining stool samples, particularly from children. PMID:17267627

  11. Effects of Kettlebell Training on Aerobic Capacity.

    PubMed

    Falatic, J Asher; Plato, Peggy A; Holder, Christopher; Finch, Daryl; Han, Kyungmo; Cisar, Craig J

    2015-07-01

    This study examined the effects of a kettlebell training program on aerobic capacity. Seventeen female National Collegiate Athletic Association Division I collegiate soccer players (age: 19.7 ± 1.0 years, height: 166.1 ± 6.4 cm, weight: 64.2 ± 8.2 kg) completed a graded exercise test to determine maximal oxygen consumption (V?O2max). Participants were assigned to a kettlebell intervention group (KB) (n = 9) or a circuit weight-training (CWT) control group (n = 8). Participants in the KB group completed a kettlebell snatch test to determine individual snatch repetitions. Both groups trained 3 days a week for 4 weeks in addition to their off-season strength and conditioning program. The KB group performed the 15:15 MVO2 protocol (20 minutes of kettlebell snatching with 15 seconds of work and rest intervals). The CWT group performed multiple free-weight and dynamic body-weight exercises as part of a continuous circuit program for 20 minutes. The 15:15 MVO2 protocol significantly increased V?O2max in the KB group. The average increase was 2.3 ml·kg?¹·min?¹, or approximately a 6% gain. There was no significant change in V?O2max in the CWT control group. Thus, the 4-week 15:15 MVO2 kettlebell protocol, using high-intensity kettlebell snatches, significantly improved aerobic capacity in female intercollegiate soccer players and could be used as an alternative mode to maintain or improve cardiovascular conditioning. PMID:26102260

  12. ?-alanine Supplementation Fails to Increase Peak Aerobic Power or Ventilatory Threshold in Aerobically Trained Males.

    PubMed

    Greer, Beau Kjerulf; Katalinas, Matthew E; Shaholli, Danielle M; Gallo, Paul M

    2016-03-01

    The purpose of the present study was to determine the effect of 30 days of ?-alanine supplementation on peak aerobic power and ventilatory threshold (VT) in aerobically fit males. Fourteen males (28.8 ± 9.8 yrs) were assigned to either a ?-alanine (SUPP) or placebo (PLAC) group; groups were matched for VT as it was the primary outcome measure. ?-alanine supplementation consisted of 3 g/day for 7 days, and 6 g/day for the remaining 23 days. Before and after the supplementation period, subjects performed a continuous, graded cycle ergometry test to determine VO2 peak and VT. Metabolic data were analyzed using a 2 × 2 ANOVA with repeated measures. Thirty days of ?-alanine supplementation (SUPP) did not increase VO2 peak (4.05 ± 0.6 vs. 4.14 ± 0.6 L/min) as compared to the placebo (PLAC) group (3.88 ± 0.2 vs. 3.97 ± 0.2 L/min) (p > .05). VT did not significantly improve in either the SUPP (3.21 ± 0.5 vs. 3.33 ± 0.5 L/min) or PLAC (3.19 ± 0.1 vs. 3.20 ± 0.1 L/min) group (p > .05). In conclusion, 30 days of ?-alanine supplementation had no effect on VO2 peak or VT in aerobically trained athletes. PMID:25299148

  13. Culturable Aerobic and Facultative Anaerobic Intestinal Bacterial Flora of Black Cobra (Naja naja karachiensis) in Southern Pakistan

    PubMed Central

    Iqbal, Junaid; Sagheer, Mehwish; Tabassum, Nazneen; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2014-01-01

    Using morphological analysis and biochemical testing, here for the first time, we determined the culturable gut bacterial flora (aerobes and facultative anaerobes) in the venomous Black Cobra (Naja naja karachiensis) from South Asia. The findings revealed that these snakes inhabit potentially pathogenic bacteria including Serratia marcescens, Pseudomonas aeruginosa, Shewanella putrefaciens, Aeromonas hydrophila, Salmonella sp., Moraxella sp., Bacillus sp., Ochrobactrum anthropi, and Providencia rettgeri. These findings are of concern, as injury from snake bite can result in wound infections and tissue necrosis leading to sepsis/necrotizing fasciitis and/or expose consumers of snake meat/medicine in the community to infections. PMID:25002979

  14. Metabolism of 2-methylpropene (isobutylene) by the aerobic bacterium Mycobacterium sp. strain ELW1.

    PubMed

    Kottegoda, Samanthi; Waligora, Elizabeth; Hyman, Michael

    2015-03-01

    An aerobic bacterium (Mycobacterium sp. strain ELW1) that utilizes 2-methylpropene (isobutylene) as a sole source of carbon and energy was isolated and characterized. Strain ELW1 grew on 2-methylpropene (growth rate = 0.05 h(-1)) with a yield of 0.38 mg (dry weight) mg 2-methylpropene(-1). Strain ELW1 also grew more slowly on both cis- and trans-2-butene but did not grow on any other C2 to C5 straight-chain, branched, or chlorinated alkenes tested. Resting 2-methylpropene-grown cells consumed ethene, propene, and 1-butene without a lag phase. Epoxyethane accumulated as the only detected product of ethene oxidation. Both alkene consumption and epoxyethane production were fully inhibited in cells exposed to 1-octyne, suggesting that alkene oxidation is initiated by an alkyne-sensitive, epoxide-generating monooxygenase. Kinetic analyses indicated that 1,2-epoxy-2-methylpropane is rapidly consumed during 2-methylpropene degradation, while 2-methyl-2-propen-1-ol is not a significant metabolite of 2-methylpropene catabolism. Degradation of 1,2-epoxy-2-methylpropane by 2-methylpropene-grown cells led to the accumulation and further degradation of 2-methyl-1,2-propanediol and 2-hydroxyisobutyrate, two sequential metabolites previously identified in the aerobic microbial metabolism of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Growth of strain ELW1 on 2-methylpropene, 1,2-epoxy-2-methylpropane, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate was fully inhibited when cobalt ions were omitted from the growth medium, while growth on 3-hydroxybutyrate and other substrates was unaffected by the absence of added cobalt ions. Our results suggest that, like aerobic MTBE- and TBA-metabolizing bacteria, strain ELW1 utilizes a cobalt/cobalamin-dependent mutase to transform 2-hydroxyisobutyrate. Our results have been interpreted in terms of their impact on our understanding of the microbial metabolism of alkenes and ether oxygenates. PMID:25576605

  15. Metabolism of 2-Methylpropene (Isobutylene) by the Aerobic Bacterium Mycobacterium sp. Strain ELW1

    PubMed Central

    Kottegoda, Samanthi; Waligora, Elizabeth

    2015-01-01

    An aerobic bacterium (Mycobacterium sp. strain ELW1) that utilizes 2-methylpropene (isobutylene) as a sole source of carbon and energy was isolated and characterized. Strain ELW1 grew on 2-methylpropene (growth rate = 0.05 h?1) with a yield of 0.38 mg (dry weight) mg 2-methylpropene?1. Strain ELW1 also grew more slowly on both cis- and trans-2-butene but did not grow on any other C2 to C5 straight-chain, branched, or chlorinated alkenes tested. Resting 2-methylpropene-grown cells consumed ethene, propene, and 1-butene without a lag phase. Epoxyethane accumulated as the only detected product of ethene oxidation. Both alkene consumption and epoxyethane production were fully inhibited in cells exposed to 1-octyne, suggesting that alkene oxidation is initiated by an alkyne-sensitive, epoxide-generating monooxygenase. Kinetic analyses indicated that 1,2-epoxy-2-methylpropane is rapidly consumed during 2-methylpropene degradation, while 2-methyl-2-propen-1-ol is not a significant metabolite of 2-methylpropene catabolism. Degradation of 1,2-epoxy-2-methylpropane by 2-methylpropene-grown cells led to the accumulation and further degradation of 2-methyl-1,2-propanediol and 2-hydroxyisobutyrate, two sequential metabolites previously identified in the aerobic microbial metabolism of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Growth of strain ELW1 on 2-methylpropene, 1,2-epoxy-2-methylpropane, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate was fully inhibited when cobalt ions were omitted from the growth medium, while growth on 3-hydroxybutyrate and other substrates was unaffected by the absence of added cobalt ions. Our results suggest that, like aerobic MTBE- and TBA-metabolizing bacteria, strain ELW1 utilizes a cobalt/cobalamin-dependent mutase to transform 2-hydroxyisobutyrate. Our results have been interpreted in terms of their impact on our understanding of the microbial metabolism of alkenes and ether oxygenates. PMID:25576605

  16. Comparison of aerobic and anaerobic biotreatment of municipal solid waste.

    PubMed

    Borglin, Sharon E; Hazen, Terry C; Oldenburg, Curtis M; Zawislanski, Peter T

    2004-07-01

    To increase the operating lifetime of landfills and to lower leachate treatment costs, an increasing number of municipal solid waste (MSW) landfills are being managed as either aerobic or anaerobic bioreactors. Landfill gas composition, respiration rates, and subsidence were measured for 400 days in 200-L tanks filled with fresh waste materials to compare the relative effectiveness of the two treatments. Tanks were prepared to provide the following conditions: (1) air injection and leachate recirculation (aerobic), (2) leachate recirculation (anaerobic), and (3) no treatment (anaerobic). Respiration tests on the aerobic wet tank showed a steady decrease in oxygen consumption rates from 1.3 mol/day at 20 days to 0.1 mol/day at 400 days. Aerobic wet tanks produced, on average, 6 mol of carbon dioxide (CO2)/kg of MSW as compared with anaerobic wet tanks, which produced 2.2 mol methane/kg of MSW and 2.0 mol CO2/kg methane. Over the test period, the aerobic tanks settled on average 35%, anaerobic tanks settled 21.7%, and the no-treatment tank settled 7.5%, equivalent to overall mass loss in the corresponding reactors. Aerobic tanks reduced stabilization time and produced negligible odor compared with anaerobic tanks, possibly because of the 2 orders of magnitude lower leachate ammonia levels in the aerobic tank. Both treatment regimes provide the opportunity for disposal and remediation of liquid waste. PMID:15303294

  17. Multidrug Resistance in Bacteria

    PubMed Central

    Nikaido, Hiroshi

    2010-01-01

    Large amounts of antibiotics used for human therapy, as well as for farm animals and even for fish in aquaculture, resulted in the selection of pathogenic bacteria resistant to multiple drugs. Multidrug resistance in bacteria may be generated by one of two mechanisms. First, these bacteria may accumulate multiple genes, each coding for resistance to a single drug, within a single cell. This accumulation occurs typically on resistance (R) plasmids. Second, multidrug resistance may also occur by the increased expression of genes that code for multidrug efflux pumps, extruding a wide range of drugs. This review discusses our current knowledge on the molecular mechanisms involved in both types of resistance. PMID:19231985

  18. Bacteria TMDL Projects 

    E-print Network

    Wythe, Kathy

    2007-01-01

    stream_source_info Bacteria TMDL projects.pdf.txt stream_content_type text/plain stream_size 2550 Content-Encoding ISO-8859-1 stream_name Bacteria TMDL projects.pdf.txt Content-Type text/plain; charset=ISO-8859-1 tx H2O... of the projects are listed below. ? Peach CreekWater Quality Improvement Project ? Monitoring and Educational Programs Focused on Bacteria and Nutrient Runoff on Dairy Operations in the LeonWatershed ? Development of the Plum CreekWPP ? Impact of Proper...

  19. Development of Aerobic Fitness in Young Team Sport Athletes.

    PubMed

    Harrison, Craig B; Gill, Nicholas D; Kinugasa, Taisuke; Kilding, Andrew E

    2015-07-01

    The importance of a high level of aerobic fitness for team sport players is well known. Previous research suggests that aerobic fitness can be effectively increased in adults using traditional aerobic conditioning methods, including high-intensity interval and moderate-intensity continuous training, or more recent game-based conditioning that involves movement and skill-specific tasks, e.g. small-sided games. However, aerobic fitness training for youth team sport players has received limited attention and is likely to differ from that for adults due to changes in maturation. Given young athletes experience different rates of maturation and technical skill development, the most appropriate aerobic fitness training modes and loading parameters are likely to be specific to the developmental stage of a player. Therefore, we analysed studies that investigated exercise protocols to enhance aerobic fitness in young athletes, relative to growth and maturation, to determine current best practice and limitations. Findings were subsequently used to guide an evidence-based model for aerobic fitness development. During the sampling stage (exploration of multiple sports), regular participation in moderate-intensity aerobic fitness training, integrated into sport-specific drills, activities and skill-based games, is recommended. During the specialisation stage (increased commitment to a chosen sport), high-intensity small-sided games should be prioritised to provide the simultaneous development of aerobic fitness and technical skills. Once players enter the investment stage (pursuit of proficiency in a chosen sport), a combination of small-sided games and high-intensity interval training is recommended. PMID:25855365

  20. Ovariectomy results in differential shifts in gut microbiota in low versus high aerobic capacity rats

    PubMed Central

    Cox-York, Kimberly A; Sheflin, Amy M; Foster, Michelle T; Gentile, Christopher L; Kahl, Amber; Koch, Lauren G; Britton, Steven L; Weir, Tiffany L

    2015-01-01

    The increased risk for cardiometabolic disease with the onset of menopause is widely studied and likely precipitated by the decline in endogenous estradiol (E2), yet the precise mechanisms are unknown. The gut microbiome is involved in estrogen metabolism and has been linked to metabolic disease, suggesting its potential involvement in the postmenopausal phenotype. Furthermore, menopause-associated risk factors, as well as gut ecology, are altered with exercise. Therefore, we studied microbial changes in an ovariectomized (OVX vs. Sham) rat model of high (HCR) and low (LCR) intrinsic aerobic capacity (n = 8–10/group) in relation to changes in body weight/composition, glucose tolerance, and liver triglycerides (TG). Nine weeks after OVX, HCR rats were moderately protected against regional adipose tissue gain and liver TG accumulation (P < 0.05 for both). Microbial diversity and number of the Bacteroidetes phylum were significantly increased in LCR with OVX, but unchanged in HCR OVX relative to Sham. Plasma short-chain fatty acids (SCFA), produced by bacteria in the gut and recognized as metabolic signaling molecules, were significantly greater in HCR Sham relative to LCR Sham rats (P = 0.05) and were decreased with OVX in both groups. These results suggest that increased aerobic capacity may be protective against menopause-associated cardiometabolic risk and that gut ecology, and production of signaling molecules such as SCFA, may contribute to the mediation. PMID:26265751

  1. Insight into the mechanism of carbon steel corrosion under aerobic and anaerobic conditions.

    PubMed

    El Mendili, Y; Abdelouas, A; Bardeau, J-F

    2013-06-21

    We particularly focused our study on identifying the corrosion products formed at 30 °C on carbon steel under aerobic and anaerobic conditions and on following their evolution with time due to enhanced microbial activity under environmental and geological conditions. The nature and structural properties of corrosion products were investigated by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD) and confocal micro-Raman spectroscopy. Structural characterisation clearly showed the formation of iron oxides (magnetite and maghemite) under aerobic conditions. Under anaerobic conditions, the first corrosion product formed on the steel surface was nanocrystalline mackinawite, which was then followed by a fast transformation process into the pyrrhotite phase, and the Raman spectrum of monoclinic pyrrhotite was proposed for the first time. Finally, this study also shows that in the context of geological disposal of radioactive waste, the corrosion of carbon steel containers in anoxic and sulphidogenic environments sustained by sulphate-reducing bacteria may not be a problem notably due to the formation of a passive layer on the steel surface. PMID:23652337

  2. Volatilization and Precipitation of Tellurium by Aerobic, Tellurite-Resistant Marine Microbes? †

    PubMed Central

    Ollivier, Patrick R. L.; Bahrou, Andrew S.; Marcus, Sarah; Cox, Talisha; Church, Thomas M.; Hanson, Thomas E.

    2008-01-01

    Microbial resistance to tellurite, an oxyanion of tellurium, is widespread in the biosphere, but the geochemical significance of this trait is poorly understood. As some tellurite resistance markers appear to mediate the formation of volatile tellurides, the potential contribution of tellurite-resistant microbial strains to trace element volatilization in salt marsh sediments was evaluated. Microbial strains were isolated aerobically on the basis of tellurite resistance and subsequently examined for their capacity to volatilize tellurium in pure cultures. The tellurite-resistant strains recovered were either yeasts related to marine isolates of Rhodotorula spp. or gram-positive bacteria related to marine strains within the family Bacillaceae based on rRNA gene sequence comparisons. Most strains produced volatile tellurides, primarily dimethyltelluride, though there was a wide range of the types and amounts of species produced. For example, the Rhodotorula spp. produced the greatest quantities and highest diversity of volatile tellurium compounds. All strains also produced methylated sulfur compounds, primarily dimethyldisulfide. Intracellular tellurium precipitates were a major product of tellurite metabolism in all strains tested, with nearly complete recovery of the tellurite initially provided to cultures as a precipitate. Different strains appeared to produce different shapes and sizes of tellurium containing nanostructures. These studies suggest that aerobic marine yeast and Bacillus spp. may play a greater role in trace element biogeochemistry than has been previously assumed, though additional work is needed to further define and quantify their specific contributions. PMID:18849455

  3. Evaluation of microbial transport during aerobic bioaugmentation of an RDX-contaminated aquifer.

    PubMed

    Crocker, Fiona H; Indest, Karl J; Jung, Carina M; Hancock, Dawn E; Fuller, Mark E; Hatzinger, Paul B; Vainberg, Simon; Istok, Jonathan D; Wilson, Edward; Michalsen, Mandy M

    2015-11-01

    In situ bioaugmentation with aerobic hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-degrading bacteria is being considered for treatment of explosives-contaminated groundwater at Umatilla Chemical Depot, Oregon (UMCD). Two forced-gradient bacterial transport tests of site groundwater containing chloride or bromide tracer and either a mixed culture of Gordonia sp. KTR9 (xplA (+)Km(R)), Rhodococcus jostii RHA1 (pGKT2 transconjugant; xplA (+)Km(R)) and Pseudomonas fluorescens I-C (xenB (+)), or a single culture of Gordonia sp. KTR9 (xplA (+); i.e. wild-type) were conducted at UMCD. Groundwater monitoring evaluated cell viability and migration in the injection well and downgradient monitoring wells. Enhanced degradation of RDX was not evaluated in these demonstrations. Quantitative PCR analysis of xplA, the kanamycin resistance gene (aph), and xenB indicated that the mixed culture was transported at least 3 m within 2 h of injection. During a subsequent field injection of bioaugmented groundwater, strain KTR9 (wild-type) migrated up to 23-m downgradient of the injection well within 3 days. Thus, the three RDX-degrading strains were effectively introduced and transported within the UMCD aquifer. This demonstration represents an innovative application of bioaugmentation to potentially enhance RDX biodegradation in aerobic aquifers. PMID:26438043

  4. Characterisation of the aerobic bacterial flora of boid snakes: application of MALDI-TOF mass spectrometry.

    PubMed

    Plenz, Bastian; Schmidt, Volker; Grosse-Herrenthey, Anke; Krüger, Monika; Pees, Michael

    2015-03-14

    The aim of this study was to identify aerobic bacterial isolates from the respiratory tract of boids with matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry (MALDI-TOF MS). From 47 boid snakes, swabs from the oral cavity, tracheal wash samples and, in cases in which postmortem examination was performed, pulmonary tissue samples were taken. Each snake was classified as having inflammation of the respiratory tract and/or oral cavity, or without evidence of inflammation based on combination of clinical, cytological and histopathological findings. Samples collected from the respiratory tract and oral cavity were inoculated onto routine media and bacteria were cultured aerobically. All morphologically distinct individual colonies obtained were analysed using MALDI-TOF MS. Unidentified isolates detected in more than three snakes were selected for further 16S rDNA PCR and sequencing. Among all examined isolates (n=243), 49 per cent (n=119) could be sufficiently speciated using MALDI-TOF MS. Molecular biology revealed several bacterial species that have not been previously described in reptiles. With an average of 6.3 different isolates from the respiratory tract and/or oral cavity, boids with inflammatory disease harboured significantly more bacterial species than boids without inflammatory disease (average 2.8 isolates). PMID:25487809

  5. Simultaneous heterotrophic nitrification and aerobic denitrification by the marine origin bacterium Pseudomonas sp. ADN-42.

    PubMed

    Jin, Ruofei; Liu, Tianqi; Liu, Guangfei; Zhou, Jiti; Huang, Jianyu; Wang, Aijie

    2015-02-01

    Recent research has highlighted the existence of some bacteria that are capable of performing heterotrophic nitrification and have a phenomenal ability to denitrify their nitrification products under aerobic conditions. A high-salinity-tolerant strain ADN-42 was isolated from Hymeniacidon perleve and found to display high heterotrophic ammonium removal capability. This strain was identified as Pseudomonas sp. via 16S rRNA gene sequence analysis. Gene cloning and sequencing analysis indicated that the bacterial genome contains N2O reductase function (nosZ) gene. NH3-N removal rate of ADN-42 was very high. And the highest removal rate was 6.52 mg/L?·?h in the presence of 40 g/L NaCl. Under the condition of pure oxygen (DO >8 mg/L), NH3-N removal efficiency was 56.9 %. Moreover, 38.4 % of oxygen remained in the upper gas space during 72 h without greenhouse gas N2O production. Keeping continuous and low level of dissolved oxygen (DO <3 mg/L) was helpful for better denitrification performance. All these results indicated that the strain has heterotrophic nitrification and aerobic denitrification abilities, which guarantee future application in wastewater treatment. PMID:25432342

  6. Aerobic and anaerobic methane oxidation in terrestrial mud volcanoes in the Northern Apennines

    NASA Astrophysics Data System (ADS)

    Wrede, C.; Brady, S.; Rockstroh, S.; Dreier, A.; Kokoschka, S.; Heinzelmann, S. M.; Heller, C.; Reitner, J.; Taviani, M.; Daniel, R.; Hoppert, M.

    2012-07-01

    Methane oxidizing prokaryotes are ubiquitous in oxic and anoxic habitats wherever C1-compounds are present. Thus, methane saturated mud volcano fluids should be a preferred habitat of methane consuming prokaryotes, using the readily available electron donors. In order to understand the relevance of methane as a carbon and energy source in mud volcano communities, we investigate the diversity of prokaryotic organisms involved in oxidation of methane in fluid samples from the Salse di Nirano mud volcano field situated in the Northern Apennines. Cell counts were at approximately 0.7 × 106 microbial cells/ml. A fraction of the microbial biomass was identified as ANME (anaerobic methanotroph) archaea by fluorescence in situ hybridization (FISH) analysis. They are associated in densely colonized flakes, of some tens of ?m in diameter, embedded in a hyaline matrix. Diversity analysis based on the 16S rDNA genes, retrieved from amplified and cloned environmental DNA, revealed a high proportion of archaea, involved in anaerobic oxidation of methane (AOM). Aerobic methane-oxidizing proteobacteria could be highly enriched from mud volcano fluids, indicating the presence of aerobic methanotrophic bacteria, which may contribute to methane oxidation, whenever oxygen is readily available. The results imply that biofilms, dominated by ANME archaea, colonize parts of the mud volcano venting system.

  7. Laboratory evaluation of bioaugmentation for aerobic treatment of RDX in groundwater.

    PubMed

    Fuller, Mark E; Hatzinger, Paul B; Condee, Charles W; Andaya, Christina; Vainberg, Simon; Michalsen, Mandy M; Crocker, Fiona H; Indest, Karl J; Jung, Carina M; Eaton, Hillary; Istok, Jonathan D

    2015-02-01

    The potential for bioaugmentation with aerobic explosive degrading bacteria to remediate hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated aquifers was demonstrated. Repacked aquifer sediment columns were used to examine the transport and RDX degradation capacity of the known RDX degrading bacterial strains Gordonia sp. KTR9 (modified with a kanamycin resistance gene) Pseudomonas fluorescens I-C, and a kanamycin resistant transconjugate Rhodococcus jostii RHA1 pGKT2:Km+. All three strains were transported through the columns and eluted ahead of the conservative bromide tracer, although the total breakthrough varied by strain. The introduced cells responded to biostimulation with fructose (18 mg L(-1), 0.1 mM) by degrading dissolved RDX (0.5 mg L(-1), 2.3 µM). The strains retained RDX-degrading activity for at least 6 months following periods of starvation when no fructose was supplied to the column. Post-experiment analysis of the soil indicated that the residual cells were distributed along the length of the column. When the strains were grown to densities relevant for field-scale application, the cells remained viable and able to degrade RDX for at least 3 months when stored at 4 °C. These results indicate that bioaugmentation may be a viable option for treating RDX in large dilute aerobic plumes. PMID:25503243

  8. Evaluation of Biodegradability of Waste Before and After Aerobic Treatment

    NASA Astrophysics Data System (ADS)

    Suchowska-Kisielewicz, Monika; J?drczak, Andrzej; Sadecka, Zofia

    2014-12-01

    An important advantage of use of an aerobic biostabilization of waste prior to its disposal is that it intensifies the decomposition of the organic fraction of waste into the form which is easily assimilable for methanogenic microorganisms involved in anaerobic decomposition of waste in the landfill. In this article it is presented the influence of aerobic pre-treatment of waste as well as leachate recirculation on susceptibility to biodegradation of waste in anaerobic laboratory reactors. The research has shown that in the reactor with aerobically treated waste stabilized with recilculation conversion of the organic carbon into the methane is about 45% higher than in the reactor with untreated waste stabilized without recirculation.

  9. Aerobic microbial mineralization of dichloroethene as sole carbon substrate

    SciTech Connect

    Bradley, P.M.; Chapelle, F.H.

    2000-01-01

    Microorganisms indigenous to the bed sediments of a black-water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (10{sup 7} final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.

  10. Considerations in prescribing preflight aerobic exercise for astronauts

    NASA Technical Reports Server (NTRS)

    Frey, Mary Anne Bassett

    1987-01-01

    The physiological effects of prolonged exposure to weightlessness are discussed together with the effects of aerobic exercise on human characteristics affected by weightlessness. It is noted that, although early data on orthostatic intolerance after spaceflight led to a belief that a high level of aerobic fitness for astronauts was detrimental to orthostatic tolerance on return to earth, most of the data available today do not suport this contention. Aerobic fitness was found to be beneficial to cardiovascular function and to mental performance; therefore, it may be important in performing extravehicular activities during flight.

  11. HERITABILITY OF AEROBIC POWER OF INDIVIDUALS IN NORTHEAST BRAZIL

    PubMed Central

    Souza, EC; Oliveira, MV; do Nascimento, LFE; Dantas, PMS

    2014-01-01

    The objective of this study was to evaluate the genetic and environmental contribution to variation in aerobic power in monozygotic (MZ) and dizygotic (DZ) twins. The sample consisted of 20 MZ individuals (12 females and 8 males) and 16 DZ individuals (12 females and 4 males), aged from 8 to 26 years, residents in Natal, Rio Grande do Norte. The twins were assessed by a multistage fitness test. The rate of heritability found for aerobic power was 77%. Based on the results, the estimated heritability was largely responsible for the differences in aerobic power. This implies that such measures are under strong genetic influence. PMID:25435668

  12. Systematic genomic analysis reveals the complementary aerobic and anaerobic respiration capacities of the human gut microbiota

    PubMed Central

    Ravcheev, Dmitry A.; Thiele, Ines

    2014-01-01

    Because of the specific anatomical and physiological properties of the human intestine, a specific oxygen gradient builds up within this organ that influences the intestinal microbiota. The intestinal microbiome has been intensively studied in recent years, and certain respiratory substrates used by gut inhabiting microbes have been shown to play a crucial role in human health. Unfortunately, a systematic analysis has not been previously performed to determine the respiratory capabilities of human gut microbes (HGM). Here, we analyzed the distribution of aerobic and anaerobic respiratory reductases in 254 HGM genomes. In addition to the annotation of known enzymes, we also predicted a novel microaerobic reductase and novel thiosulfate reductase. Based on this comprehensive assessment of respiratory reductases in the HGM, we proposed a number of exchange pathways among different bacteria involved in the reduction of various nitrogen oxides. The results significantly expanded our knowledge of HGM metabolism and interactions in bacterial communities. PMID:25538694

  13. Characteristics of Biological Nitrogen Removal in a Multiple Anoxic and Aerobic Biological Nutrient Removal Process

    PubMed Central

    Wang, Huoqing; Guan, Yuntao; Li, Li; Wu, Guangxue

    2015-01-01

    Two sequencing batch reactors, one with the conventional anoxic and aerobic (AO) process and the other with the multiple AO process, were operated to examine characteristics of biological nitrogen removal, especially of the multiple AO process. The long-term operation showed that the total nitrogen removal percentage of the multiple AO reactor was 38.7% higher than that of the AO reactor. In the multiple AO reactor, at the initial SBR cycle stage, due to the occurrence of simultaneous nitrification and denitrification, no nitrite and/or nitrate were accumulated. In the multiple AO reactor, activities of nitrite oxidizing bacteria were inhibited due to the multiple AO operating mode applied, resulting in the partial nitrification. Denitrifiers in the multiple AO reactor mainly utilized internal organic carbon for denitrification, and their activities were lower than those of denitrifiers in the AO reactor utilizing external organic carbon. PMID:26491676

  14. Study of aerobic granular sludge stability in a continuous-flow membrane bioreactor.

    PubMed

    Corsino, S F; Campo, R; Di Bella, G; Torregrossa, M; Viviani, G

    2016-01-01

    A granular continuous-flow membrane bioreactor with a novel hydrodynamic configuration was developed to evaluate the stability of aerobic granular sludge (AGS). Under continuous-flow operation (Period I), AGS rapidly lost their structural integrity resulting in loose and fluffy microbial aggregates in which filamentous bacteria were dominant. The intermittent feeding (Period II) allowed obtaining the succession of feast and famine conditions that favored the increase in AGS stability. Although no further breakage occurred, the formation of new granules was very limited, owing to the absence of the hydraulic selection pressure. These results noted the necessity to ensure, on the one hand the succession of feast/famine conditions, and on the other, the hydraulic selection pressure that allows flocculent sludge washout. This preliminary study shows that the proposed configuration could meet the first aspect; in contrast, biomass selection needs to be improved. PMID:26526094

  15. Bacteria in shear flow

    E-print Network

    Marcos, Ph.D. Massachusetts Institute of Technology

    2011-01-01

    Bacteria are ubiquitous and play a critical role in many contexts. Their environment is nearly always dynamic due to the prevalence of fluid flow: creeping flow in soil, highly sheared flow in bodily conduits, and turbulent ...

  16. Indicator For Pseudomonas Bacteria

    NASA Technical Reports Server (NTRS)

    Margalit, Ruth

    1990-01-01

    Characteristic protein extracted and detected. Natural protein marker found in Pseudomonas bacteria. Azurin, protein containing copper readily extracted, purified, and used to prepare antibodies. Possible to develop simple, fast, and accurate test for marker carried out in doctor's office.

  17. Characterization and screening of plant probiotic traits of bacteria isolated from rice seeds cultivated in Argentina.

    PubMed

    Ruiz, Dante; Ruiza, Dante; Agaras, Betina; de Werra, Patrice; de Werrab, Patrice; Wall, Luis G; Valverde, Claudio

    2011-12-01

    Many seeds carry endophytes, which ensure good chances of seedling colonization. In this work, we have studied the seed-borne bacterial flora of rice varieties cultivated in the northeast of Argentina. Surface-sterilized husked seeds of the rice cultivars CT6919, El Paso 144, CAMBA, and IRGA 417 contained an average of 5×10(6) CFU/g of mesophilic and copiotrophic bacteria. Microbiological, physiological, and molecular characterization of a set of 39 fast-growing isolates from the CT6919 seeds revealed an important diversity of seed-borne mesophiles and potential plant probiotic activities, including diazotrophy and antagonism of fungal pathogens. In fact, the seed-borne bacterial flora protected the rice seedlings against Curvularia sp. infection. The root colonization pattern of 2 Pantoea isolates from the seeds was studied by fluorescence microscopy of the inoculated axenic rice seedlings. Both isolates strongly colonized the site of emergence of the lateral roots and lenticels, which may represent the entry sites for endophytic spreading. These findings suggest that rice plants allow grain colonization by bacterial species that may act as natural biofertilizers and bioprotectives early from seed germination. PMID:22203552

  18. Comparative Genomics of DNA Fragments from Six Antarctic Marine Planktonic Bacteria

    PubMed Central

    Grzymski, Joseph J.; Carter, Brandon J.; DeLong, Edward F.; Feldman, Robert A.; Ghadiri, Amir; Murray, Alison E.

    2006-01-01

    Six environmental fosmid clones from Antarctic coastal water bacterioplankton were completely sequenced. The genome fragments harbored small-subunit rRNA genes that were between 85 and 91% similar to those of their nearest cultivated relatives. The six fragments span four phyla, including the Gemmatimonadetes, Proteobacteria (? and ?), Bacteroidetes, and high-G+C gram-positive bacteria. Gene-finding and annotation analyses identified 244 total open reading frames. Amino acid comparisons of 123 and 113 Antarctic bacterial amino acid sequences to mesophilic homologs from G+C-specific and SwissProt/UniProt databases, respectively, revealed widespread adaptation to the cold. The most significant changes in these Antarctic bacterial protein sequences included a reduction in salt-bridge-forming residues such as arginine, glutamic acid, and aspartic acid, reduced proline contents, and a reduction in stabilizing hydrophobic clusters. Stretches of disordered amino acids were significantly longer in the Antarctic sequences than in the mesophilic sequences. These characteristics were not specific to any one phylum, COG role category, or G+C content and imply that underlying genotypic and biochemical adaptations to the cold are inherent to life in the permanently subzero Antarctic waters. PMID:16461708

  19. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate-oxidizing bacteria.

    PubMed

    Wang, Han; Fotidis, Ioannis A; Angelidaki, Irini

    2015-11-01

    Ammonia-rich substrates can cause inhibition on anaerobic digestion process. Syntrophic acetate-oxidizing bacteria (SAOB) and hydrogenotrophic methanogens are important for the ammonia inhibitory mechanism on anaerobic digestion. The roles and interactions of SAOB and hydrogenotrophic methanogens to ammonia inhibition effect are still unclear. The aim of the current study was to determine the ammonia toxicity levels of various pure strains of SAOB and hydrogenotrophic methanogens. Moreover, ammonia toxicity on the syntrophic-cultivated strains of SAOB and hydrogenotrophic methanogens was tested. Thus, four hydrogenotrophic methanogens (i.e. Methanoculleus bourgensis, Methanobacterium congolense, Methanoculleu thermophilus and Methanothermobacter thermautotrophicus), two SAOB (i.e. Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) and their syntrophic cultivation were assessed under 0.26, 3, 5 and 7 g NH4 (+)-N L(-1). The results showed that some hydrogenotrophic methanogens were equally, or in some cases, more tolerant to high ammonia levels compared to SAOB. Furthermore, a mesophilic hydrogenotrophic methanogen was more sensitive to ammonia toxicity compared to thermophilic methanogens tested in the study, which is contradicting to the general belief that thermophilic methanogens are more vulnerable to high ammonia loads compared to mesophilic. This unexpected finding underlines the fact that the complete knowledge of ammonia inhibition effect on hydrogenotrophic methanogens is still absent. PMID:26490748

  20. Issues of Health, Appearance and Physical Activity in Aerobic Classes for Women

    ERIC Educational Resources Information Center

    D'Abundo, Michelle Lee

    2009-01-01

    The purpose of this research was to explore what appearance-focused messages were conveyed by aerobic instructors in aerobic classes for women. This qualitative research was influenced by the concept of wellness and how feminist pedagogy can be applied to promote individuals' well-being in aerobic classes. The practices of five aerobic instructors…

  1. MATE CHOICE AND AEROBIC CAPACITY IN RED MARK A. CHAPPELL'), MARLENE ZUK, TORGEIR S. JOHNSEN and

    E-print Network

    Saltzman, Wendy

    MATE CHOICE AND AEROBIC CAPACITY IN RED JUNGLEFOWL MARK A. CHAPPELL'), MARLENE ZUK, TORGEIR S survival value to offspring. One possible index of male quality is aerobic capacity (the metabolic basis valuable, high aerobic capacity would be a direct signal of male genetic quality. If aerobic capacity

  2. Recovery of Nickel and Cobalt from Laterite Tailings by Reductive Dissolution under Aerobic Conditions Using Acidithiobacillus Species.

    PubMed

    Marrero, J; Coto, O; Goldmann, S; Graupner, T; Schippers, A

    2015-06-01

    Biomining of sulfidic ores has been applied for almost five decades. However, the bioprocessing of oxide ores such as laterites lags commercially behind. Recently, the Ferredox process was proposed to treat limonitic laterite ores by means of anaerobic reductive dissolution (AnRD), which was found to be more effective than aerobic bioleaching by fungi and other bacteria. We show here that the ferric iron reduction mediated by Acidithiobacillus thiooxidans can be applied to an aerobic reductive dissolution (AeRD) of nickel laterite tailings. AeRD using a consortium of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans extracted similar amounts of nickel (53-57%) and cobalt (55-60%) in only 7 days as AnRD using Acidithiobacillus ferrooxidans. The economic and environmental advantages of AeRD for processing of laterite tailings comprise no requirement for an anoxic atmosphere, 1.8-fold less acid consumption than for AnRD, as well as nickel and cobalt recovered in a ferrous-based pregnant leach solution (PLS), facilitating the subsequent metal recovery. In addition, an aerobic acid regeneration stage is proposed. Therefore, AeRD process development can be considered as environmentally friendly for treating laterites with low operational costs and as an attractive alternative to AnRD. PMID:25923144

  3. Effect of whey protein coating on quality attributes of low-fat, aerobically packaged sausage during refrigerated storage.

    PubMed

    Shon, J; Chin, K B

    2008-08-01

    Whey protein-based edible coating was used to reduce oxidative degradation and microbial growth of low-fat sausages (LFSs) stored at 4 degrees C for 8 wk, under aerobic package. Whey protein coating reduced (P<0.05) thiobarbituric acid-reactive substances (TBARS) and peroxide value (PV) formation compared to control sausages. The percent inhibition of TBARS and PV for whey protein-coated sausages, compared to the control, was 31.3% and 27.1%, respectively. The ability of the whey protein coating to provide a moisture barrier for the sausages was reduced (P<0.05). In addition, a reduction of moisture loss by 36.7% compared to the control was achieved by whey coating. However, whey protein coating of LFSs did not inhibit the growth of either the total number of aerobic bacteria or of Listeria monocytogenes. These results indicated that whey protein coating had an antioxidative activity in LFSs under aerobic package during refrigerated storage. PMID:19241536

  4. Simultaneous nitritation-denitritation for the treatment of high-strength nitrogen in hypersaline wastewater by aerobic granular sludge.

    PubMed

    Corsino, Santo Fabio; Capodici, Marco; Morici, Claudia; Torregrossa, Michele; Viviani, Gaspare

    2016-01-01

    Fish processing industries produce wastewater containing high amounts of salt, organic matter and nitrogen. Biological treatment of such wastewaters could be problematic due to inhibitory effects exerted by high salinity levels. In detail, high salt concentrations lead to the accumulation of nitrite due to the inhibition of nitrite-oxidizing bacteria. The feasibility of performing simultaneous nitritation and denitritation in the treatment of fish canning wastewater by aerobic granular sludge was evaluated, and simultaneous nitritation-denitritation was successfully sustained at salinities up to 50 gNaCl L(-1), with a yield of over 90%. The total nitrogen concentration in the effluent was less than 10 mg L(-1) at salinities up to 50 gNaCl L(-1). Nitritation collapsed above 50 gNaCl L(-1), and then, the only nitrogen removal mechanism was represented by heterotrophic synthesis. In contrast, organic matter removal was not affected by salinity but was instead affected by the organic loading rate (OLR). Both COD and BOD removal efficiencies were over 90%. The COD fractionation analysis indicated that aerobic granules were able to remove more than 95% of the particulate organic matter. Finally, results obtained in this work noted that aerobic granular sludge had an excellent ability to adapt under adverse environmental conditions. PMID:26512811

  5. Highly efficient aerobic oxidation of alkenes over unsupported nanogold.

    PubMed

    Boualleg, Malika; Guillois, Kevin; Istria, Bertrand; Burel, Laurence; Veyre, Laurent; Basset, Jean-Marie; Thieuleux, Chloé; Caps, Valérie

    2010-08-01

    An octylsilane-stabilized colloidal dispersion of 2 nm crystalline gold nanoparticles is highly active and selective for the aerobic oxidations of stilbene and cyclohexene in methylcyclohexane. PMID:20559599

  6. [Mechanisms of nitrous oxide emission during livestock manure aerobic composting].

    PubMed

    Wu, Wei-Xiang; Li, Li-Jie; Lü, Hao-Hao; Wang, Cheng; Deng, Hui

    2012-06-01

    Aerobic composting is an effective way to treat and recycle livestock manure. However, the aerobic composting of livestock manure is a potential source of the greenhouse gas nitrous oxide (N2O), which closely relates to the global greenhouse effect and ozone depletion. With the expansion of livestock industry and the dramatic increasing yield of manure compost, the N2O emission during the aerobic composting has become a severe problem. The researches on the mechanisms of N2O emission during livestock manure composting have attracted increasing concerns. In this paper, the recent researches on the N2O generation approaches, emission dynamics, potential affecting factors, and microbiological mechanisms of N2O emission during livestock manure aerobic composting were reviewed, and the measures to control the N2O emission during composting process were summarized. Some perspectives for the future researches in this field were suggested. PMID:22937664

  7. REDUCTIONS OF ENTERIC MICROORGANISMS DURING AEROBIC SLUDGE DIGESTION

    EPA Science Inventory

    Seasonal variations in the reductions of total coliform, fecal coliform, fecal streptococci, and enterovirus densities that occur during conventional aerobic sludge digestion in cold climates were characterized. Also, the potential to improve reductions in the densities of these ...

  8. Aerobic Glycolysis: Meeting the Metabolic Requirements of Cell Proliferation

    E-print Network

    Vander Heiden, Matthew G.

    Warburg's observation that cancer cells exhibit a high rate of glycolysis even in the presence of oxygen (aerobic glycolysis) sparked debate over the role of glycolysis in normal and cancer cells. Although it has been ...

  9. [Selective extraction of metals from zinc concentrate by association of chemolithotrophic bacteria].

    PubMed

    Vardanian, N S; Vardanian, A K

    2011-01-01

    Ability for selective extraction of copper and zinc from zinc concentrate using association of chemolithotrophic bacteria was investigated. In the presence of bacterial association, the rate of desalinization of zinc, copper, and iron was increased 3-fold, 4-5-fold, and 2-fold, respectively. Zinc, copper, and iron were levigated with the most significant rate. It was revealed that addition of Fe3+ 2 g/l resulted in reduction of iron desalinization and in 3-fold increase of desalinization rate of copper at constant dissolution rate of mineral zinc. It is suggested that the intensification of copper desalinization is connected with the activity of sulfur-oxidizing bacteria able to activate the mineral surface via elimination of passivation layer of elemental sulfur. It was concluded that sulfur-oxidizing bacteria play a significant role in copper desalinization from zinc concentrate. A unique strain of mesophile sulfur-oxidizing bacteria was isolated from desalinization pulp of zinc concentrate; in the perspective, it may serve as efficient candidate for performing of selective extraction of copper from zinc concentrate. PMID:22232898

  10. Methane Emission From the Congo Deep Sea Fan and Subsequent Aerobic Oxidation in the Quaternary Tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Handley, L.; Cooke, M. P.; Talbot, H. M.; Wagner, T.

    2008-12-01

    The Congo Fan is a well-documented region of important methane (CH4) storage and gas seepage: gas hydrates abound at and just below the sediment surface as do large deeply-buried reservoirs of thermogenic methane linked with hydrocarbon source rocks. In the Congo Fan, both sources of methane are intimately connected through a complex network of faults, structuring this massive sediment wedge in a unique way. Methane release from both reservoirs has the potential to drive or respond to changes in local and global climate, thus causing changes in ocean chemical properties and biotic responses. Understanding these poorly-constrained mechanisms of methane emission and reconstructing the history of past emissions in the ocean is the main focus of our study. The ultimate fate of CH4 is, typically, its oxidation to CO2; this process can occur aerobically and anaerobically. Compared to anaerobic processes, aerobic methane oxidation, and its underlying mechanisms and possible feedbacks for the ocean-climate system, has received little attention. Here we present molecular evidence from Congo Fan sediments for aerobic methane oxidation and highlight how the process may play a previously unrecognised role in carbon cycling and oxygen availability in the water column. Bacteriohopanepolyols (BHPs) are lipid membrane constituents and occur with a wide range of structural and functional variability in many bacteria. Amino-BHPs are produced in large abundances by methane-oxidising bacteria and the 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) is a highly specific biomarker for aerobic methane oxidation. The Congo Fan record (ODP Leg 175, Site 1075; 2996 m depth) spans the last 1 Myr and reveals remarkable organic biomarker preservation, with a suite of 13 different BHPs identified in most sediment horizons, including aminopentol. Aminopentol abundance varies widely throughout the section and appears to do so cyclically, with markedly greater concentrations between ca. 500 and 600 ka and compound-specific stable carbon isotope analyses confirm that the amino-BHPs are of methanotrophic origin. Although suspected to be primarily biogenic in origin, ?13C values of ca. -42‰ further suggest a potential contribution from deep thermogenic sources to the emitted methane. Ongoing sea surface temperature reconstruction, using the TEX86 proxy, seeks to investigate potential perturbations in local climate with relation to these previously unrecognized emission events. The hopanoid record pushes direct evidence for aerobic microbial oxidation of methane far back into the geological record. This process is believed to be intrinsically linked with methane gas hydrate dissolution. Thus, the variability in amino-BHP abundance could provide an indicator for methane emission events, directly linking key aspects of structural geology with gas hydrate stability, deep ocean processes, and methane cycling.

  11. Characterization of polyhydroxyalkanoate-producing bacteria isolated from sludge of commercial pig farms for producing methyl esters.

    PubMed

    Chang, Chin-Feng; Chen, Li-Chun; Hsieh, Cheng-Jer; Chang, Kai-Chun; Su, Jung-Jeng

    2013-01-01

    The objectives of this work were to isolate and characterize the polyhydroxyalkanoate (PHA) producing bacteria in enriched piggery sludge and make methyl esters from PHA for industrial applications. The strain ECAe24 isolated from piggery sludge with the highest PHA production was selected to produce PHA and then methyl ester by trans-esterification using glucose as substrate under mesophilic conditions. The final product after trans-esterification consisted of approximately 75.39% of fatty acid methyl ester and was identified as decanoic acid-3-hydroxy-methyl ester, octanoic acid-3-hydroxy-methyl ester, and some other contents. The novelty of this study is to use PHA-producing bacteria from piggery sludge to make fatty acid methyl esters which can be used as materials for producing biodiesel from piggery wastes. PMID:24292464

  12. Proton motive force in growing Streptococcus lactis and Staphylococcus aureus cells under aerobic and anaerobic conditions.

    PubMed

    Kashket, E R

    1981-04-01

    Measurements of the electrochemical gradient of hydrogen ions, which gives rise to the proton motive force (PMF), were carried out with growing Streptococcus lactis and Staphylococcus aureus cells. The facultative anaerobe was chosen in order to compare the PMF of cells growing aerobically and anaerobically. It was expected that during aerobic growth the cells would have a higher PMF than during anaerobic growth, because the H+-translocating ATPase (BF0F1) operates in the direction of H+ influx and ATP synthesis during respiration, whereas under anaerobic conditions the BF0F1 hydrolyzes glycolytically generated ATP and establishes the proton gradient by extruding H+. The electrical component of the PMF, delta psi, and the chemical gradient of H+, delta pH, were measured with radiolabeled tetraphenylphosphonium and benzoate ions. In both S. lactis and S. aureus cells, the PMF was constant during the exponential phase of batch growth and decreased in the stationary phase. In both species of bacteria, the exponential-phase PMF was not affected by varying the growth rate by adding different sugars to the medium. The relative contributions of delta psi and delta pH to the PMF, however, depended on the pH of the medium. The internal pH of S. aureus was constant at pH 7.4 to 7.6 under all conditions of growth tested. Under aerobic conditions, the delta psi of exponential phase S. aureus remained fairly constant at 160 to 170 mV. Thus, the PMF was 250 to 270 mV in cells growing aerobically in media at pH 6 and progressively lower in media of higher pH, reaching 195 to 205 mV at pH 7. Under anaerobic conditions, the delta psi ranged from 100 to 120 mV in cells at pH 6.3 to 7, resulting in a PMF of 150 to 140 mV. Thus, the mode of energy metabolism (i.e., respiration versus fermentation) and the pH of the medium are the two important factors influencing the PMF of these gram-positive cells during growth. PMID:6260743

  13. The fecal bacteria

    USGS Publications Warehouse

    Sadowsky, Michael J., (Edited By); Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  14. Spoilage of light (PSE-like) and dark turkey meat under aerobic or modified atmosphere package: microbial indicators and their relationship with total volatile basic nitrogen.

    PubMed

    Fraqueza, M J; Ferreira, M C; Barreto, A S

    2008-01-01

    1. The aim of this work was to evaluate the shelf life of turkey meat from different colour categories (Pale, Soft and Exudative (PSE)-like), intermediate and dark), packaged under aerobic or modified atmosphere (MAP) conditions; also to establish a relationship between microbial quality and total volatile basic nitrogen (TVB-N), evaluating its capacity for shelf life determination. 2. Breasts were selected according to luminance (L*) and pH(24): L >/= 51 and pH < 5.8 for light colour, 43 < L < 51 for intermediate colour, L 5.8 for dark colour. Sliced meat was packaged under aerobic or MAP conditions with 50% N(2) and 50% CO(2), then stored in the dark at 0 +/- 1 degrees C for periods of 12 or 25 d. Meat under aerobic conditions was evaluated for microbiological characteristics and TVB-N on d 0, 5 and 12. This evaluation was extended to include d 19 and 25 when samples were under MAP conditions. 3. The dark meat group after 12 d of storage in aerobiosis presented significantly higher plate counts of aerobic mesophilic, psychrotrophic micro-organisms and higher TVB-N than other meat colour categories. The shelf life of turkey meat under MAP was one week longer for intermediate and light colour meat (20 d) than for dark meat. TVB-N values of 20 to 30 mg NH(3)/100 g turkey meat correspond to advanced spoilage stages. We proposed 14 mg NH(3)/100 g as the limit of freshness acceptability for turkey meat. 4. TVB-N was an indicator of turkey meat microbial spoilage but was not a suitable early predictor for microbial spoilage and in particular for turkey meat stored under MAP conditions because counts of micro-organisms were moderately correlated (Pseudomonas spp. and Enterobacteriaceae) with this index, as they were inhibited by MAP gas mixture and storage temperature used in the present study. PMID:18210285

  15. Sludge minimization using aerobic/anoxic treatment technology

    SciTech Connect

    Mines, R.O. Jr.; Kalch, R.S.

    1999-07-01

    The objective of this investigation was to demonstrate through a bench-scale study that using an aerobic/anoxic sequence to treat wastewater and biosolids could significantly reduce the production of biosolids (sludge). A bench-scale activated sludge reactor and anoxic digester were operated for approximately three months. The process train consisted of a completely-mixed aerobic reactor with wasting of biosolids to an anoxic digester for stabilization. The system was operated such that biomass produced in the aerobic activated sludge process was wasted to the anoxic digester; and biomass produced in the anoxic digester was wasted back to the activated sludge process. A synthetic wastewater consisting of bacto-peptone nutrient broth was fed to the liquid process train. Influent and effluent to the aerobic biological process train were analytically tested, as were the contents of mixed liquor in the aerobic reactor and anoxic digester. Overall removal efficiencies for the activated sludge process with regard to COD, TKN, NH{sub 3}-N, and alkalinity averaged 91, 89, 98, and 38%, respectively. The overall average sludge production for the aerobic/anoxic process was 24% less than the overall average sludge production from a conventional activated sludge bench-scale system fed the same substrate and operated under similar mean cell residence times.

  16. Aerobic microbial mineralization of dichloroethene as sole carbon substrate

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.

    2000-01-01

    Microorganisms indigenous to the bed sediments of a black- water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.Microorganisms indigenous to the bed sediments of a black-water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.

  17. Personality, Metabolic Rate and Aerobic Capacity

    PubMed Central

    Terracciano, Antonio; Schrack, Jennifer A.; Sutin, Angelina R.; Chan, Wayne; Simonsick, Eleanor M.; Ferrucci, Luigi

    2013-01-01

    Personality traits and cardiorespiratory fitness in older adults are reliable predictors of health and longevity. We examined the association between personality traits and energy expenditure at rest (basal metabolic rate) and during normal and maximal sustained walking. Personality traits and oxygen (VO2) consumption were assessed in 642 participants from the Baltimore Longitudinal Study of Aging. Results indicate that personality traits were mostly unrelated to resting metabolic rate and energy expenditure at normal walking pace. However, those who scored lower on neuroticism (r?=? ?0.12) and higher on extraversion (r?=?0.11), openness (r?=?0.13), and conscientiousness (r?=?0.09) had significantly higher energy expenditure at peak walking pace. In addition to greater aerobic capacity, individuals with a more resilient personality profile walked faster and were more efficient in that they required less energy per meter walked. The associations between personality and energy expenditure were not moderated by age or sex, but were in part explained by the proportion of fat mass. In conclusion, differences in personality may matter the most during more challenging activities that require cardiorespiratory fitness. These findings suggest potential pathways that link personality to health outcomes, such as obesity and longevity. PMID:23372763

  18. Dancing the aerobics ''hearing loss'' choreography

    NASA Astrophysics Data System (ADS)

    Pinto, Beatriz M.; Carvalho, Antonio P. O.; Gallagher, Sergio

    2002-11-01

    This paper presents an overview of gymnasiums' acoustic problems when used for aerobics exercises classes (and similar) with loud noise levels of amplified music. This type of gymnasium is usually a highly reverberant space, which is a consequence of a large volume surrounded by hard surfaces. A sample of five schools in Portugal was chosen for this survey. Noise levels in each room were measured using a precision sound level meter, and analyzed to calculate the standardized daily personal noise exposure levels (LEP,d). LEP,d values from 79 to 91 dB(A) were found to be typical values in this type of room, inducing a health risk for its occupants. The reverberation time (RT) values were also measured and compared with some European legal requirements (Portugal, France, and Belgium) for nearly similar situations. RT values (1 kHz) from 0.9 s to 2.8 s were found. These reverberation time values clearly differentiate between good and acoustically inadequate rooms. Some noise level and RT limits for this type of environment are given and suggestions for the improvement of the acoustical environment are shown. Significant reductions in reverberation time values and noise levels can be obtained by simple measures.

  19. Addition of crude glycerine as strategy to balance the C/N ratio on sewage sludge thermophilic and mesophilic anaerobic co-digestion.

    PubMed

    Silvestre, G; Fernández, B; Bonmatí, A

    2015-10-01

    The effect of adding crude glycerine during continuous sewage sludge anaerobic digestion was investigated under thermophilic and mesophilic temperatures. Addition of CGY at thermophilic temperature range showed a negative impact on stability and performance of the process, even at low doses. The extreme pH values of CGY, together with the rapid release of VFA, causes SS alkalinity fail to control pH drop. On the contrary, at mesophilic temperature range the process performs steadily, with 148% increase in methane production when CGY represented 1% v/v of the influent (27% of influent COD). Further CGY percentages did not show any added improvement; the biomass shift, due to a high C/N ratio, could explain this behaviour. Results suggested that CGY can be used as co-substrate of SS anaerobic digestion though, depending on the characteristics of CGY, and on operational conditions, different parameters should be taken into account to achieve a steady and consistent operation. PMID:26143573

  20. Protein Dynamics and Stability: The Distribution of Atomic Fluctuations in Thermophilic and Mesophilic Dihydrofolate Reductase Derived Using Elastic Incoherent Neutron Scattering

    SciTech Connect

    Meinhold, Lars; Clement, David; Tehei, M; Daniel, R. M.; Finney, J.L.; Smith, Jeremy C

    2008-11-01

    The temperature dependence of the dynamics of mesophilic and thermophilic dihydrofolate reductase is examined using elastic incoherent neutron scattering. It is demonstrated that the distribution of atomic displacement amplitudes can be derived from the elastic scattering data by assuming a (Weibull) functional form that resembles distributions seen in molecular dynamics simulations. The thermophilic enzyme has a significantly broader distribution than its mesophilic counterpart. Furthermore, although the rate of increase with temperature of the atomic mean-square displacements extracted from the dynamic structure factor is found to be comparable for both enzymes, the amplitudes are found to be slightly larger for the thermophilic enzyme. Therefore, these results imply that the thermophilic enzyme is the more flexible of the two.

  1. Evidence for a role of biosurfactants produced by Pseudomonas fluorescens in the spoilage of fresh aerobically stored chicken meat.

    PubMed

    Mellor, Glen E; Bentley, Jessica A; Dykes, Gary A

    2011-08-01

    Fresh chicken meat is a fat-rich environment and we therefore hypothesised that production of biosurfactants to increase bioavailability of fats may represent one way in which spoilage bacteria might enhance the availability of nutrients. Numbers of Pseudomonas were determined on a total of 20 fresh and 20 spoiled chicken thighs with skin. A total of 400 randomly isolated Pseudomonas colonies from fresh (200) and spoiled (200) chicken were screened for the presence of biosurfactant production. Biosurfactant producing strains represented 5% and 72% of the Pseudomonas spp. isolates from fresh (mean count 2.3 log(10) cfu g(-1)) and spoiled (mean count 7.4 log(10) cfu g(-1)) chicken skin, respectively. Partially-purified biosurfactants derived from a subgroup of four Pseudomonasfluorescens strains obtained through the screening process were subsequently used to investigate the role that the addition of these compounds plays in the spoilage of aerobically stored chicken. Emulsification potential of the four selected biosurfactants was measured against a range of hydrocarbons and oils. All four biosurfactants displayed a greater ability to emulsify rendered chicken fat than hydrocarbons (paraffin liquid, toluene and hexane) and oils (canola, olive, sunflower and vegetable). Storage trials (4 °C) of chicken meat treated with the four selected biosurfactants revealed a significantly greater (P < 0.05) total aerobic count in biosurfactant treated samples, as compared to untreated samples on each day (0, 1, 2, 3) of storage. For biosurfactant treated samples the greatest increase in total aerobic count (1.3-1.7 log(10) cfu g(-1)) occurred following one day of incubation. These results indicate that biosurfactants produced by Pseudomonas spp. may play an important role in the spoilage of aerobically stored chicken meat by making nutrients more freely available and providing strains producing them with a competitive advantage. PMID:21569958

  2. Structure Analysis of Aerobic Granule from a Sequencing Batch Reactor for Organic Matter and Ammonia Nitrogen Removal

    PubMed Central

    Li, Jun; Cai, Ang; Wang, Danjun; Chen, Chao; Ni, Yongjiong

    2014-01-01

    Aerobic granules were cultivated in a sequencing batch reactor (SBR). COD and ammonia nitrogen removal rate were 94% and 99%, respectively. The diameter, settling velocity and SVI10 of granules ranged from 2 to 5 mm, 80 to 110 m/h and about 40 mL/g, respectively. Freezing microtome images, DO concentration profiles by microelectrode, distribution of bacteria and EPS by confocal laser scanning microscopy (CLSM) show that the aerobic granules have a three-layer structure. Each layer has different thickness, character, bacteria, and DO transfer rate. A hypothesis for granule structure is proposed: the first layer, the surface of the granule, is composed mostly of heterotrophic organisms for organic matter removal, with a thickness range from 150 to 350 ?m; the second layer, mostly composed of autotrophic organisms for ammonia nitrogen removal, with a thickness range from 250 to 450 ?m; the third layer, located in the core of the granule, has mostly an inorganic composition and contains pores and channels. PMID:24577284

  3. Metabolic Pathways for Degradation of Aromatic Hydrocarbons by Bacteria.

    PubMed

    Ladino-Orjuela, Guillermo; Gomes, Eleni; da Silva, Roberto; Salt, Christopher; Parsons, John R

    2016-01-01

    The aim of this revision was to build an updated collection of information focused on the mechanisms and elements involved in metabolic pathways of aromatic hydrocarbons by bacteria. Enzymes as an expression of the genetic load and the type of electron acceptor available, as an environmental factor, were highlighted. In general, the review showed that both aerobic routes and anaerobic routes for the degradation of aromatic hydrocarbons are divided into two pathways. The first, named the upper pathways, from the original compound to central intermediate compounds still containing the aromatic ring but with the benzene nucleus chemically destabilized. The second, named the lower pathway, begins with ring de-aromatização and subsequent cleavage, resulting in metabolites that can be used by bacteria in the production of biomass. Under anaerobic conditions the five mechanisms of activation of the benzene ring described show the diversity of chemical reactions that take place. Obtaining carbon and energy from an aromatic hydrocarbon molecule is a process that exhibits the high complexity level of the metabolic apparatus of anaerobic microorganisms. The ability of these bacteria to express enzymes that catalyze reactions, known only in non-biological conditions, using final electron acceptors with a low redox potential, is a most interesting topic. The discovery of phylogenetic and functional characteristics of cultivable and non-cultivable hydrocarbon degrading bacteria has been made possible by improvements in molecular research techniques such as SIP (stable isotope probing) making trace of (13)C, (15)N and (18)O into nucleic acids and proteins. PMID:26613990

  4. Inactivation of Murine Norovirus 1 and Bacteroides fragilis Phage B40-8 by Mesophilic and Thermophilic Anaerobic Digestion of Pig Slurry ?

    PubMed Central

    Baert, Leen; De Gusseme, Bart; Boon, Nico; Verstraete, Willy; Debevere, Johan; Uyttendaele, Mieke

    2010-01-01

    Mesophilic (37°C) and thermophilic (52°C) anaerobic digestion of pig slurry induced at least a 4-log decrease in murine norovirus 1, used as a surrogate virus for porcine norovirus, after 13 and 7 days, respectively. Bacteroides fragilis phage B40-8, employed as a universal viral model, was lowered by 2.5 log after 7 days. The viral titer declined due to temperature and matrix effects. PMID:20080994

  5. Multicenter Evaluation of the Bruker MALDI Biotyper CA System for the Identification of Clinical Aerobic Gram-Negative Bacterial Isolates

    PubMed Central

    Faron, Matthew L.; Buchan, Blake W.; Hyke, Josh; Madisen, Neil; Lillie, Jennifer L.; Granato, Paul A.; Wilson, Deborah A.; Procop, Gary W.; Novak-Weekley, Susan; Marlowe, Elizabeth; Cumpio, Joven; Griego-Fullbright, Christen; Kindig, Sandra; Timm, Karen; Young, Stephen; Ledeboer, Nathan A.

    2015-01-01

    The prompt and accurate identification of bacterial pathogens is fundamental to patient health and outcome. Recent advances in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) have revolutionized bacterial identification in the clinical laboratory, but uniform incorporation of this technology in the U.S. market has been delayed by a lack of FDA-cleared systems. In this study, we conducted a multicenter evaluation of the MALDI Biotyper CA (MBT-CA) System (Bruker Daltonics Inc, Billerica, MA) for the identification of aerobic gram-negative bacteria as part of a 510(k) submission to the FDA. A total of 2,263 aerobic gram negative bacterial isolates were tested representing 23 genera and 61 species. Isolates were collected from various clinical sources and results obtained from the MBT-CA System were compared to DNA sequencing and/or biochemical testing. Isolates that failed to report as a "high confidence species ID" [log(score) ?2.00] were re-tested using an extraction method. The MBT-CA System identified 96.8% and 3.1% of isolates with either a "high confidence" or a "low confidence" [log(score) value between 1.70 and <2.00] species ID, respectively. Two isolates did not produce acceptable confidence scores after extraction. The MBT-CA System correctly identified 99.8% (2,258/2,263) to genus and 98.2% (2,222/2,263) to species level. These data demonstrate that the MBT-CA System provides accurate results for the identification of aerobic gram-negative bacteria. PMID:26529504

  6. Mesophilic anaerobic digestion of pulp and paper industry biosludge-long-term reactor performance and effects of thermal pretreatment.

    PubMed

    Kinnunen, V; Ylä-Outinen, A; Rintala, J

    2015-12-15

    The pulp and paper industry wastewater treatment processes produce large volumes of biosludge. Limited anaerobic degradation of lignocellulose has hindered the utilization of biosludge, but the processing of biosludge using anaerobic digestion has recently regained interest. In this study, biosludge was used as a sole substrate in long-term (400 d) mesophilic laboratory reactor trials. Nine biosludge batches collected evenly over a period of one year from a pulp and paper industry wastewater treatment plant had different solid and nutrient (nitrogen, phosphorus, trace elements) characteristics. Nutrient characteristics may vary by a factor of 2-11, while biomethane potentials (BMPs) ranged from 89 to 102 NL CH4 kg(-1) VS between batches. The BMPs were enhanced by 39-88% with thermal pretreatments at 105-134 °C. Despite varying biosludge properties, stable operation was achieved in reactor trials with a hydraulic retention time (HRT) of 14 d. Hydrolysis was the process limiting step, ceasing gas production when the HRT was shortened to 10 days. However, digestion with an HRT of 10 days was feasible after thermal pretreatment of the biosludge (20 min at 121 °C) due to enhanced hydrolysis. The methane yield was 78 NL CH4 kg(-1) VS for untreated biosludge and was increased by 77% (138 NL CH4 kg(-1) VS) after pretreatment. PMID:26397452

  7. From mesophilic to thermophilic digestion: the transitions of anaerobic bacterial, archaeal, and fungal community structures in sludge and manure samples.

    PubMed

    Sun, Weimin; Yu, Guangwei; Louie, Tiffany; Liu, Tong; Zhu, Chengsheng; Xue, Gang; Gao, Pin

    2015-12-01

    The shift of microbial communities during a transition from mesophilic anaerobic digestion (MAD) to thermophilic anaerobic digestion (TAD) was characterized in two treatments. One treatment was inoculated with sludge and the other was inoculated with manure. In this study, methane was produced both in MAD and TAD, but TAD has slightly more methane produced than MAD. A broad phylogenetic spectrum of bacterial, archaeal, and fungal taxa at thermophilic conditions was detected. Coprothermobacter, Bacillus, Haloplasma, Clostridiisalibacter, Methanobacterium, Methanothermobacter, Saccharomycetales, Candida, Alternaria, Cladosporium, and Penicillium were found almost exclusively in TAD, suggesting their adaptation to thermophilic conditions and ecological roles in digesting the organic compounds. The characterization of the lesser-known fungal community revealed that fungi probably constituted an important portion of the overall community within TAD and contributed to this process by degrading complex organic compounds. The shift of the microbial communities between MAD and TAD implied that temperature drastically affected the microbial diversity in anaerobic digestion. In addition, the difference in microbial communities between sludge and manure indicated that different source of inoculum also affected the microbial diversity and community. PMID:26245681

  8. Effects of triclosan, diclofenac, and nonylphenol on mesophilic and thermophilic methanogenic activity and on the methanogenic communities.

    PubMed

    Symsaris, Evangelos C; Fotidis, Ioannis A; Stasinakis, Athanasios S; Angelidaki, Irini

    2015-06-30

    In this study, a toxicity assay using a mesophilic wastewater treatment plant sludge-based (SI) and a thermophilic manure-based inoculum (MI), under different biomass concentrations was performed to define the effects of diclofenac (DCF), triclosan (TCS), and nonylphenol (NP) on anaerobic digestion (AD) process. Additionally, the influence of DCF, TCS, and NP on the relative abundance of the methanogenic populations was investigated. Results obtained demonstrated that, in terms of methane production, SI inoculum was more resistant to the toxicity effect of DCF, TCS, and NP, compared to the MI inoculum. The IC50 values were 546, 35, and 363 mg L(-1) for SI inoculum and 481, 32, and 74 mg L(-1) for MI inoculum for DCF, TCS, and NP, respectively. For both inocula, higher biomass concentrations reduced the toxic effect of TCS (higher methane production up to 64%), contrary to DCF, where higher biomass loads decreased methane yield up to 31%. Fluorescence in situ hybridization analysis showed that hydrogenotrophic methanogens were more resistant to the inhibitory effect of DCF, TCS, and NP compared to aceticlastic methanogens. PMID:25768988

  9. The role of biological processes in reducing both odor impact and pathogen content during mesophilic anaerobic digestion.

    PubMed

    Orzi, Valentina; Scaglia, Barbara; Lonati, Samuele; Riva, Carlo; Boccasile, Gabriele; Alborali, Giovanni Loris; Adani, Fabrizio

    2015-09-01

    Mesophilic anaerobic digestion (MAD) produces renewable energy, but it also plays a role in reducing the impact of digestates, both by reducing odor and pathogen content. Ten full-scale biogas plants characterized by different plant designs (e.g. single digesters, parallel or serial digesters), plant powers (ranging from 180 to 999 kWe), hydraulic retention time (HRT) (ranging between 20 to 70 days) and feed mixes were monitored and odors and pathogens were observed in both ingestates and digestates. Results obtained indicated that MAD reduced odors (OU) from, on average, OUingestate=99,106±149,173 OU m(-2) h(-1) (n=15) to OU digestate=1106±771 OU m(-2) h(-1) (n=15). Pathogens were also reduced during MAD both because of ammonia production during the process and competition for substrate between pathogens and indigenous microflora, i.e. Enterobacteriaceae from 6.85?10(3)±1.8?10(1) to 1.82?10(1)±3.82?10(1); fecal Coliform from 1.82?10(4)±9.09 to 2.45?10(1)±3.8?10(1); Escherichia coli from 8.72?10(3)±2.4?10(1) to 1.8?10(1)±2.94?10(1); Clostridium perfringens from 6.4?10(4)±7.7 to 5.2?10(3)±8.1 (all data are expressed as CFU g(-1) ww). Plants showed different abilities to reduce pathogen indicators, depending on the pH value and toxic ammonia content. PMID:25925189

  10. Shifts in bacterial and archaeal community structures during the batch biomethanation of Ulva biomass under mesophilic conditions.

    PubMed

    Kim, Jaai; Jung, Heejung; Lee, Changsoo

    2014-10-01

    Mesophilic biomethanation of Ulva biomass was performed in a batch bioreactor, and a high organic removal of 77% was obtained on the basis of chemical oxygen demand (COD) after a month of operation. The estimated methane yield was 0.43 ± 0.02 L CH4/g COD(removed) which is close to the theoretical methane potential. Transitions of bacterial and archaeal community structures, associated with process performance data, were investigated using a combination of molecular fingerprinting and biostatistical tools. During the operation, archaeal community structure had no significant changes while bacterial community structure shifted continuously and dynamically. The reactor completely stabilized volatile fatty acids (primarily acetate and propionate) accumulated from the acidogenesis phase, with Methanosaeta- and Methanolinea-related microbes respectively being the main aceticlastic and hydrogenotrophic methanogens. Methanolinea- and Syntrophobacter-related populations were likely the key members to form a syntrophic propionate-degrading consortium. A Methanolinea-related population was likely the dominant methane producer in the experimental reactor. PMID:25086435

  11. Evaluation of biodegradability of phenol and bisphenol A during mesophilic and thermophilic municipal solid waste anaerobic digestion using 13C-labeled contaminants.

    PubMed

    Limam, Intissar; Mezni, Mohamed; Guenne, Angéline; Madigou, Céline; Driss, Mohamed Ridha; Bouchez, Théodore; Mazéas, Laurent

    2013-01-01

    In this paper, the isotopic tracing using (13)C-labeled phenol and bisphenol A was used to study their biodegradation during anaerobic digestion of municipal solid waste. Microcosms were incubated anaerobically at 35 °C (mesophilic conditions) and 55 °C (thermophilic conditions) without steering. A continuous follow-up of the production of biogas (CH(4) and CO(2)), was carried out during 130 d until the establishment of stable methanogenesis. Then (13)C(12)-BPA, and (13)C(6)-phenol were injected in microcosms and the follow-up of their degradation was performed simultaneously by gas chromatography isotope-ratio mass spectrometry (GC-IRMS) and gas chromatography mass spectrometry (GC-MS). Moreover, Carbon-13 Nuclear Magnetic Resonance ((13)C-NMR) Spectroscopy is used in the identification of metabolites. This study proves that the mineralization of phenol to CO(2) and CH(4) occurs during anaerobic digestion both in mesophilic and thermophilic conditions with similar kinetics. In mesophilic condition phenol degradation occurs through the benzoic acid pathway. In thermophilic condition it was not possible to identify the complete metabolic pathway as only acetate was identified as metabolite. Our results suggest that mineralization of phenol under thermophilic condition is instantaneous explaining why metabolites are not observed as they do not accumulate. No biodegradation of BPA was observed. PMID:22985591

  12. Ice-Nucleating Bacteria

    NASA Astrophysics Data System (ADS)

    Obata, Hitoshi

    Since the discovery of ice-nucleating bacteria in 1974 by Maki et al., a large number of studies on the biological characteristics, ice-nucleating substance, ice nucleation gene and frost damage etc. of the bacteria have been carried out. Ice-nucleating bacteria can cause the freezing of water at relatively warm temperature (-2.3°C). Tween 20 was good substrates for ice-nucleating activity of Pseudomonas fluorescens KUIN-1. Major fatty acids of Isolate (Pseudomonas fluorescens) W-11 grown at 30°C were palmitic, cis-9-hexadecenoic and cis-11-octadecenoic which amounted to 90% of the total fatty acids. Sequence analysis shows that an ice nucleation gene from Pseudomonas fluorescens is related to the gene of Pseudomonas syringae.

  13. [Temperature as a factor of development of psychrotolerant mycelial bacteria complexes in soils of north regions].

    PubMed

    Zenova, G M; Kozhevin, P A; Manucharova, N A; Dubrova, M S; Zviagintsev, D G

    2012-01-01

    It has been demonstrated that complexes of mycelial bacteria (actinomycetes), in which the amount of psychrotolerant actinomycetes reaches hundreds of thousands of CFU/g of the soil (frequently exceeding the portion of mesophilic forms), are developed in peat and podzolic soils of the tundra and taiga at low temperatures. As actinomycetes grow and develop in cold soils, their mycelium increases in length. Use of the molecular in situ hybridization method (fluorescent in situ hybridization, FISH) demonstrated that the portion of metabolically active mycelial actinobacteria exceeds the portion of unicellular actinobacteria in the Actinobacteria phylum. Specific peculiarities of psychrotolerant populations in relation to the spectrum of consumed substrates (histidine, mannitol, saccharose) were established by the method of multirespirometric testing. PMID:23136737

  14. Intracellular Accumulation of Glycine in Polyphosphate-Accumulating Organisms in Activated Sludge, a Novel Storage Mechanism under Dynamic Anaerobic-Aerobic Conditions.

    PubMed

    Nguyen, Hien Thi Thu; Kristiansen, Rikke; Vestergaard, Mette; Wimmer, Reinhard; Nielsen, Per Halkjær

    2015-07-01

    Dynamic anaerobic-aerobic feast-famine conditions are applied to wastewater treatment plants to select polyphosphate-accumulating organisms to carry out enhanced biological phosphorus removal. Acetate is a well-known substrate to stimulate this process, and here we show that different amino acids also are suitable substrates, with glycine as the most promising. (13)C-labeled glycine and nuclear magnetic resonance (NMR) were applied to investigate uptake and potential storage products when activated sludge was fed with glycine under anaerobic conditions. Glycine was consumed by the biomass, and the majority was stored intracellularly as free glycine and fermentation products. Subsequently, in the aerobic phase without addition of external substrate, the stored glycine was consumed. The uptake of glycine and oxidation of intracellular metabolites took place along with a release and uptake of orthophosphate, respectively. Fluorescence in situ hybridization combined with microautoradiography using (3)H-labeled glycine revealed uncultured actinobacterial Tetrasphaera as a dominant glycine consumer. Experiments with Tetrasphaera elongata as representative of uncultured Tetrasphaera showed that under anaerobic conditions it was able to take up labeled glycine and accumulate this and other labeled metabolites to an intracellular concentration of approximately 4 mM. All components were consumed under subsequent aerobic conditions. Intracellular accumulation of amino acids seems to be a novel storage strategy for polyphosphate-accumulating bacteria under dynamic anaerobic-aerobic feast-famine conditions. PMID:25956769

  15. Genome Sequence of Brevibacillus formosus F12T for a Genome-Sequencing Project for Genomic Taxonomy and Phylogenomics of Bacillus-Like Bacteria

    PubMed Central

    Wang, Jie-Ping; Liu, Guo-Hong; Chen, Qian-qian; Zhu, Yu-jing; Chen, Zheng; Che, Jian-mei

    2015-01-01

    Brevibacillus formosus F12T is a Gram-positive, spore-forming, and strictly aerobic bacterium. Here, we report the draft 6.215-Mb genome sequence of B. formosus F12T, which will provide useful information for genomic taxonomy and phylogenomics of Bacillus-like bacteria, as well as for the functional gene mining and application of B. formosus. PMID:26205874

  16. A bacterial community analysis using reverse transcription (RT) PCR which detects the bacteria with high activity in a wastewater treatment reactor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research used reverse transcription polymerase chain reaction (RT-PCR) method to help detect active bacteria in a single-tank deammonification reactor combining partial nitritation and anammox. The single-tank aerobic deammonification reactor effectively removed the ammonia in anaerobically di...

  17. Immunomodulatory Effects of Aerobic Training in Obesity

    PubMed Central

    Nickel, Thomas; Hanssen, Henner; Emslander, Ingrid; Drexel, Verena; Hertel, Gernot; Schmidt-Trucksäss, Arno; Summo, Claudia; Sisic, Zeljka; Lambert, Marius; Hoster, Eva; Halle, Martin; Weis, Michael

    2011-01-01

    Introduction. Physical inactivity and obesity are independent risk factors for atherosclerosis. We analyzed the immunomodulatory capacity of 10-week intensified exercise training (ET) in obese and lean athletes. Markers of the innate immune response were investigated in obese (ONE: ET?40?km/week) and lean athletes (LNE: ET?40?km/week and LE: ET?55?km/week). Methods. Circulating dendritic cells (DC) were analyzed by flow-cytometry for BDCA-1/-2-expression. TLR-2/-4/-7 and MyD88 were analyzed by RT-PCR and Western blot. Circulating oxLDL levels were analyzed by ELISA. Results. BDCA-1 expression at baseline was lower in ONE compared to both other groups (ONE 0.15%; LNE 0.27%; LE 0.33%; P < .05), but significantly increased in ONE after training (+50%; P < .05). In contrast, BDCA-2 expression at baseline was higher in ONE (ONE 0.25%; LNE 0.11%; LE 0.09%; P < .05) and decreased in ONE after the 10-week training period (?27%; P < .05). Gene activations of TLR-4 and TLR-7 with corresponding protein increase were found for all three groups (P < .01/P < .05) compared to pre training. A reduction of oxLDL levels was seen in ONE (?61%; P < .05). Conclusions. Intensified exercise induces an increase of BDCA-1+ DCs and TLR-4/-7 in obese athletes. We hereby describe new immune modulatory effects, which—through regular aerobic exercise—modulate innate immunity and pro-inflammatory cytokines in obesity. PMID:21461352

  18. Field Tests for Evaluating the Aerobic Work Capacity of Firefighters

    PubMed Central

    Lindberg, Ann-Sofie; Oksa, Juha; Gavhed, Désirée; Malm, Christer

    2013-01-01

    Working as a firefighter is physically strenuous, and a high level of physical fitness increases a firefighter’s ability to cope with the physical stress of their profession. Direct measurements of aerobic capacity, however, are often complicated, time consuming, and expensive. The first aim of the present study was to evaluate the correlations between direct (laboratory) and indirect (field) aerobic capacity tests with common and physically demanding firefighting tasks. The second aim was to give recommendations as to which field tests may be the most useful for evaluating firefighters’ aerobic work capacity. A total of 38 subjects (26 men and 12 women) were included. Two aerobic capacity tests, six field tests, and seven firefighting tasks were performed. Lactate threshold and onset of blood lactate accumulation were found to be correlated to the performance of one work task (rs?=??0.65 and ?0.63, p<0.01, respectively). Absolute (mL·min?1) and relative (mL·kg?1·min?1) maximal aerobic capacity was correlated to all but one of the work tasks (rs?=??0.79 to 0.55 and ?0.74 to 0.47, p<0.01, respectively). Aerobic capacity is important for firefighters’ work performance, and we have concluded that the time to row 500 m, the time to run 3000 m relative to body weight (s·kg?1), and the percent of maximal heart rate achieved during treadmill walking are the most valid field tests for evaluating a firefighter’s aerobic work capacity. PMID:23844153

  19. Hydrocarbon degrading microbial communities in bench scale aerobic biobarriers for gasoline contaminated groundwater treatment.

    PubMed

    Daghio, Matteo; Tatangelo, Valeria; Franzetti, Andrea; Gandolfi, Isabella; Papacchini, Maddalena; Careghini, Alessandro; Sezenna, Elena; Saponaro, Sabrina; Bestetti, Giuseppina

    2015-07-01

    BTEX compounds (benzene, toluene, ethylbenzene and xylenes) and methyl tert-butyl ether (MTBE) are some of the main constituents of gasoline and can be accidentally released in the environment. In this work the effect of bioaugmentation on the microbial communities in a bench scale aerobic biobarrier for gasoline contaminated water treatment was studied by 16S rRNA gene sequencing. Catabolic genes (tmoA and xylM) were quantified by qPCR, in order to estimate the biodegradation potential, and the abundance of total bacteria was estimated by the quantification of the number of copies of the 16S rRNA gene. Hydrocarbon concentration was monitored over time and no difference in the removal efficiency for the tested conditions was observed, either with or without the microbial inoculum. In the column without the inoculum the most abundant genera were Acidovorax, Bdellovibrio, Hydrogenophaga, Pseudoxanthomonas and Serpens at the beginning of the column, while at the end of the column Thauera became dominant. In the inoculated test the microbial inoculum, composed by Rhodococcus sp. CE461, Rhodococcus sp. CT451 and Methylibium petroleiphilum LMG 22953, was outcompeted. Quantitative PCR results showed an increasing in xylM copy number, indicating that hydrocarbon degrading bacteria were selected during the treatment, although only a low increase of the total biomass was observed. However, the bioaugmentation did not lead to an increase in the degradative potential of the microbial communities. PMID:25747304

  20. Stable partial nitritation for low-strength wastewater at low temperature in an aerobic granular reactor.

    PubMed

    Isanta, Eduardo; Reino, Clara; Carrera, Julián; Pérez, Julio

    2015-09-01

    Partial nitritation for a low-strength wastewater at low temperature was stably achieved in an aerobic granular reactor. A bench-scale granular sludge bioreactor was operated in continuous mode treating an influent of 70 mg N-NH4(+) L(-1) to mimic pretreated municipal nitrogenous wastewater and the temperature was progressively decreased from 30 to 12.5 °C. A suitable effluent nitrite to ammonium concentrations ratio to a subsequent anammox reactor was maintained stable during 300 days at 12.5 °C. The average applied nitrogen loading rate at 12.5 °C was 0.7 ± 0.3 g N L(-1) d(-1), with an effluent nitrate concentration of only 2.5 ± 0.7 mg N-NO3(-) L(-1). The biomass fraction of nitrite-oxidizing bacteria (NOB) in the granular sludge decreased from 19% to only 1% in 6 months of reactor operation at 12.5 °C. Nitrobacter spp. where found as the dominant NOB population, whereas Nitrospira spp. were not detected. Simulations indicated that: (i) NOB would only be effectively repressed when their oxygen half-saturation coefficient was higher than that of ammonia-oxidizing bacteria; and (ii) a lower specific growth rate of NOB was maintained at any point in the biofilm (even at 12.5 °C) due to the bulk ammonium concentration imposed through the control strategy. PMID:26001281

  1. Bacteria recovery from genetically feathered and featherless broiler carcasses after immersion chilling.

    PubMed

    Buhr, R J; Bourassa, D V; Northcutt, J K; Hinton, A; Ingram, K D; Cason, J A

    2005-09-01

    Feathered and featherless (scaleless) sibling broilers were reared and processed together to evaluate the influence of feathers and feather follicles on carcass bacteria recovery after chilling. In each experiment, broilers were inoculated 1 wk prior to processing by oral gavage with a suspension of salmonellae or Campylobacter at 106 cells/mL. Broilers were stunned and bled, and carcasses were single-tank or triple-tank scalded, defeathered, eviscerated, and washed. Carcasses were chilled for 45 min in ice and water immersion chillers with or without 20 mg of chlorine/L added. Postchill carcass rinsates were evaluated for Escherichia coli, coliforms, total aerobes, and salmonellae or Campylobacter. Following processing and immersion chilling, genetically featherless carcasses had slightly higher counts (by log10 0.35 cfu/100 mL of carcass rinsate) for E. coli, coliforms, and total aerobes than feathered carcasses. However, there were no significant differences in the prevalence of salmonellae (25%) or Campylobacter (93%) between feathered and featherless carcasses. Recovery of E. coli, coliforms, and total aerobic bacteria were lower for carcasses that were single-tank scalded, and following enrichment, salmonellae were recovered from fewer carcasses subjected to the single-tank (71%) than triple-tank (86%) scalding. Addition of chlorine to chiller water significantly decreased carcass bacteria recovery (by log10 0.43 cfu/100 mL of carcass rinsate) for E. coli, coliforms, total aerobes, and Campylobacter but did not affect salmonellae recovery. The presence of feathers and feather follicles during processing and immersion chilling appears to have minimal influence on the recovery of salmonellae or Campylobacter from carcasses sampled after immersion chilling. PMID:16206575

  2. Metabolic diversity of aromatic hydrocarbon-degrading bacteria from a petroleum-contaminated aquifer.

    PubMed

    Mikesell, M D; Kukor, J J; Olsen, R H

    We characterized bacteria from contaminated aquifers for their ability to utilize aromatic hydrocarbons under hypoxic (oxygen-limiting) conditions (initial dissolved oxygen concentration about 2 mg/l) with nitrate as an alternate electron acceptor. This is relevant to current intense efforts to establish favorable conditions for in situ bioremediation. Using samples of granular activated carbon slurries from an operating groundwater treatment system, we isolated bacteria that are able to use benzene, toluene, ethylbenzene, or p-xylene as their sole source of carbon under aerobic or hypoxic-denitrifying conditions. Direct isolation on solid medium incubated aerobically or hypoxically with the substrate supplied as vapor yielded 10(3) to 10(5) bacteria ml-1 of slurry supernatant, with numbers varying little with respect to isolation substrate or conditions. More than sixty bacterial isolates that varied in colony morphology were purified and characterized according to substrate utilization profiles and growth condition (i.e., aerobic vs. hypoxic) specificity. Strains with distinct characteristics were obtained using benzene compared with those isolated on toluene or ethylbenzene. In general, isolates obtained from direct selection on benzene minimal medium grew well under aerobic conditions but poorly under hypoxic conditions, whereas many ethylbenzene isolates grew well under both incubation conditions. We conclude that the conditions of isolation, rather than the substrate used, will influence the apparent characteristic substrate utilization range of the isolates obtained. Also, using an enrichment culture technique, we isolated a strain of Pseudomonas fluorescens, designated CFS215, which exhibited nitrate dependent degradation of aromatic hydrocarbons under hypoxic conditions. PMID:7764922

  3. PATHOGENICITY OF BIOFILM BACTERIA

    EPA Science Inventory

    There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...

  4. Culture of Bacteria 

    E-print Network

    Unknown

    2011-08-17

    site located in the lungs of an animal model, thereby enabling detection of fluorescent bacteria during the early stages of infection. In this thesis, I present a contact probe fiber bundle fluorescence micro-endoscope with a range of LED based...

  5. Aquatic Bacteria Samples

    USGS Multimedia Gallery

    On April 20, 2010, the BP Deepwater Horizon drilling platform collapsed and sank in the Gulf of Mexico, causing one of the largest oil spills in history. One of the big dilemmas in responding to the oil spil is how to clean up the oil itself. One way currently under research is to use bacteria that ...

  6. Antibiotic-Resistant Bacteria.

    ERIC Educational Resources Information Center

    Longenecker, Nevin E.; Oppenheimer, Dan

    1982-01-01

    A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)

  7. Bacteria-surface interactions

    PubMed Central

    Tuson, Hannah H.; Weibel, Douglas B.

    2013-01-01

    The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field. PMID:23930134

  8. Distributions of Manganese, Iron, and Manganese-Oxidizing Bacteria In Lake Superior Sediments of Different Organic Carbon Content

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Nealson, Kenneth H.

    1989-01-01

    Profiles of oxygen, soluble and particulate manganese and iron, organic carbon and nitrogen were examined in Lake Superior sediment cores, along with the distribution and abundance of heterotrophic and manganese oxidizing bacteria. Analyses were performed using cores collected with the submersible Johnson Sea Link II. Three cores, exhibiting a range of organic carbon content, were collected from the deepest basin in Lake Superior and the north and south ends of the Caribou trough, and brought to the surface for immediate analysis. Minielectrode profiles of oxygen concentration of the three cores were carried out using a commercially available minielectrode apparatus. Oxygen depletion to less than 1% occurred within 4 cm of the surface for two of the cores, but not until approximately 15 cm for the core from the south basin of the Caribou trough. The three cores exhibited very different profiles of soluble, as well as leachable, manganese and iron, suggesting different degrees of remobilization of these metals in the sediments. Vertical profiles of viable bacteria and Mn oxidizing bacteria, determined by plating and counting, showed that aerobic (and facultatively aerobic) heterotrophic bacteria were present at the highest concentrations near the surface and decreased steadily with depth, while Mn oxidizing bacteria were concentrations primarily at and above the oxic/anoxic interface. Soluble manganese in the pore waters, along with abundant organic carbon, appeared to enhance the presence of manganese oxidizing bacteria, even below the oxic/anoxic interface. Profiles of solid-phase leachable manganese suggested a microbial role in manganese reprecipitation in these sediments.

  9. ADAPTATIONS OF INDIGENOUS BACTERIA TO FUEL CONTAMINATION IN KARST AQUIFERS IN SOUTH-CENTRAL KENTUCKY

    USGS Publications Warehouse

    Byl, Thomas D.; Metge, David W.; Daniel T. Agymang; Bradley, Michael W.; Hileman, Gregg; Harvey, Ronald W.

    2014-01-01

    The karst aquifer systems in southern Kentucky can be dynamic and quick to change. Microorganisms that live in these unpredictable aquifers are constantly faced with environmental changes. Their survival depends upon adaptations to changes in water chemistry, taking advantage of positive stimuli and avoiding negative environmental conditions. The U.S. Geological Survey conducted a study in 2001 to determine the capability of bacteria to adapt in two distinct regions of water quality in a karst aquifer, an area of clean, oxygenated groundwater and an area where the groundwater was oxygen depleted and contaminated by jet fuel. Water samples containing bacteria were collected from one clean well and two jet fuel contaminated wells in a conduit-dominated karst aquifer. Bacterial concentrations, enumerated through direct count, ranged from 500,000 to 2.7 million bacteria per mL in the clean portion of the aquifer, and 200,000 to 3.2 million bacteria per mL in the contaminated portion of the aquifer over a twelve month period. Bacteria from the clean well ranged in size from 0.2 to 2.5 mm, whereas bacteria from one fuel-contaminated well were generally larger, ranging in size from 0.2 to 3.9 mm. Also, bacteria collected from the clean well had a higher density and, consequently, were more inclined to sink than bacteria collected from contaminated wells. Bacteria collected from the clean portion of the karst aquifer were predominantly (,95%) Gram-negative and more likely to have flagella present than bacteria collected from the contaminated wells, which included a substantial fraction (,30%) of Gram-positive varieties. The ability of the bacteria from the clean portion of the karst aquifer to biodegrade benzene and toluene was studied under aerobic and anaerobic conditions in laboratory microcosms. The rate of fuel biodegradation in laboratory studies was approximately 50 times faster under aerobic conditions as compared to anaerobic, sulfur-reducing conditions. The optimum pH for fuel biodegradation ranged from 6 to 7. These findings suggest that bacteria have adapted to water-saturated karst systems with a variety of active and passive transport mechanisms.

  10. Investigation of oxidative phosphorylation in continuous cultures. A non-equilibrium thermodynamic approach to energy transduction for Escherichia coli in aerobic condition

    NASA Astrophysics Data System (ADS)

    Ghafuri, Mohazabeh; Nosrati, Mohsen; Hosseinkhani, Saman

    2015-03-01

    Adenosine triphosphate (ATP) production in living cells is very important. Different researches have shown that in terms of mathematical modeling, the domain of these investigations is essentially restricted. Recently the thermodynamic models have been suggested for calculation of the efficiency of oxidative phosphorylation process and rate of energy loss in animal cells using chemiosmotic theory and non-equilibrium thermodynamics equations. In our previous work, we developed a mathematical model for mitochondria of animal cells. In this research, according to similarities between oxidative phosphorylation process in microorganisms and animal cells, Golfar's model was developed to predict the non-equilibrium thermodynamic behavior of the oxidative phosphorylation process for bacteria in aerobic condition. With this model the rate of energy loss, P/O ratio, and efficiency of oxidative phosphorylation were calculated for Escherichia coli in aerobic condition. The results then were compared with experimental data given by other authors. The thermodynamic model had an acceptable agreement with the experimental data.

  11. Evaluation of aerobic co-composting of penicillin fermentation fungi residue with pig manure on penicillin degradation, microbial population dynamics and composting maturity.

    PubMed

    Zhang, Zhenhua; Zhao, Juan; Yu, Cigang; Dong, Shanshan; Zhang, Dini; Yu, Ran; Wang, Changyong; Liu, Yan

    2015-12-01

    Improper treatment of penicillin fermentation fungi residue (PFFR), one of the by-products of penicillin production process, may result in environmental pollution due to the high concentration of penicillin. Aerobic co-composting of PFFR with pig manure was determined to degrade penicillin in PFFR. Results showed that co-composting of PFFR with pig manure can significantly reduce the concentration of penicillin in PFFR, make the PFFR-compost safer as organic fertilizer for soil application. More than 99% of penicillin in PFFR were removed after 7-day composting. PFFR did not affect the composting process and even promote the activity of the microorganisms in the compost. Quantitative PCR (qPCR) indicated that the bacteria and actinomycetes number in the AC samples were 40-80% higher than that in the pig-manure compost (CK) samples in the same composting phases. This research indicated that the aerobic co-composting was a feasible PFFR treatment method. PMID:26409851

  12. Effects of 12 weeks of aerobic training on autonomic modulation, mucociliary clearance, and aerobic parameters in patients with COPD

    PubMed Central

    Leite, Marceli Rocha; Ramos, Ercy Mara Cipulo; Kalva-Filho, Carlos Augusto; Freire, Ana Paula Coelho Figueira; de Alencar Silva, Bruna Spolador; Nicolino, Juliana; de Toledo-Arruda, Alessandra Choqueta; Papoti, Marcelo; Vanderlei, Luiz Carlos Marques; Ramos, Dionei

    2015-01-01

    Introduction Patients with chronic obstructive pulmonary disease (COPD) exhibit aerobic function, autonomic nervous system, and mucociliary clearance alterations. These parameters can be attenuated by aerobic training, which can be applied with continuous or interval efforts. However, the possible effects of aerobic training, using progressively both continuous and interval sessions (ie, linear periodization), require further investigation. Aim To analyze the effects of 12-week aerobic training using continuous and interval sessions on autonomic modulation, mucociliary clearance, and aerobic function in patients with COPD. Methods Sixteen patients with COPD were divided into an aerobic (continuous and interval) training group (AT) (n=10) and a control group (CG) (n=6). An incremental test (initial speed of 2.0 km·h?1, constant slope of 3%, and increments of 0.5 km·h?1 every 2 minutes) was performed. The training group underwent training for 4 weeks at 60% of the peak velocity reached in the incremental test (vVO2peak) (50 minutes of continuous effort), followed by 4 weeks of sessions at 75% of vVO2peak (30 minutes of continuous effort), and 4 weeks of interval training (5×3-minute effort at vVO2peak, separated by 1 minute of passive recovery). Intensities were adjusted through an incremental test performed at the end of each period. Results The AT presented an increase in the high frequency index (ms2) (P=0.04), peak oxygen uptake (VO2peak) (P=0.01), vVO2peak (P=0.04), and anaerobic threshold (P=0.02). No significant changes were observed in the CG (P>0.21) group. Neither of the groups presented changes in mucociliary clearance after 12 weeks (AT: P=0.94 and CG: P=0.69). Conclusion Twelve weeks of aerobic training (continuous and interval sessions) positively influenced the autonomic modulation and aerobic parameters in patients with COPD. However, mucociliary clearance was not affected by aerobic training. PMID:26648712

  13. Bioenergy production from diluted poultry manure and microbial consortium inside Anaerobic Sludge Bed Reactor at sub-mesophilic conditions.

    PubMed

    Jaxybayeva, Aigerim; Yangin-Gomec, Cigdem; Cetecioglu, Zeynep; Ozbayram, E Gozde; Yilmaz, Fatih; Ince, Orhan

    2014-01-01

    In this study, anaerobic treatability of diluted chicken manure (with an influent feed ratio of 1 kg of fresh chicken manure to 6 L of tap water) was investigated in a lab-scale anaerobic sludge bed (ASB) reactor inoculated with granular seed sludge. The ASB reactor was operated at ambient temperature (17-25°C) in order to avoid the need of external heating up to higher operating temperatures (e.g., up to 35°C for mesophilic digestion). Since heat requirement for raising the temperature of incoming feed for digestion is eliminated, energy recovery from anaerobic treatment of chicken manure could be realized with less operating costs. Average biogas production rates were calculated ca. 210 and 242 L per kg of organic matter removed from the ASB reactor at average hydraulic retention times (HRTs) of 13 and 8.6 days, respectively. Moreover, average chemical oxygen demand (COD) removal of ca. 89% was observed with suspended solids removal more than 97% from the effluent of the ASB reactor. Influent ammonia, on the other hand, did not indicate any free ammonia inhibition due to dilution of the raw manure while pH and alkalinity results showed stability during the study. Microbial quantification results indicated that as the number of bacterial community decreased, the amount of Archaea increased through the effective digestion volume of the ASB reactor. Moreover, the number of methanogens displayed an uptrend like archaeal community and a strong correlation (-0.645) was found between methanogenic community and volatile fatty acid (VFA) concentration especially acetate. PMID:25065830

  14. A Mesophilic, Autotrophic, Ammonia-Oxidizing Archaeon of Thaumarchaeal Group I.1a Cultivated from a Deep Oligotrophic Soil Horizon

    PubMed Central

    Jung, Man-Young; Park, Soo-Je; Kim, So-Jeong; Kim, Jong-Geol; Sinninghe Damsté, Jaap S.

    2014-01-01

    Soil nitrification plays an important role in the reduction of soil fertility and in nitrate enrichment of groundwater. Various ammonia-oxidizing archaea (AOA) are considered to be members of the pool of ammonia-oxidizing microorganisms in soil. This study reports the discovery of a chemolithoautotrophic ammonia oxidizer that belongs to a distinct clade of nonmarine thaumarchaeal group I.1a, which is widespread in terrestrial environments. The archaeal strain MY2 was cultivated from a deep oligotrophic soil horizon. The similarity of the 16S rRNA gene sequence of strain MY2 to those of other cultivated group I.1a thaumarchaeota members, i.e., Nitrosopumilus maritimus and “Candidatus Nitrosoarchaeum koreensis,” is 92.9% for both species. Extensive growth assays showed that strain MY2 is chemolithoautotrophic, mesophilic (optimum temperature, 30°C), and neutrophilic (optimum pH, 7 to 7.5). The accumulation of nitrite above 1 mM inhibited ammonia oxidation, while ammonia oxidation itself was not inhibited in the presence of up to 5 mM ammonia. The genome size of strain MY2 was 1.76 Mb, similar to those of N. maritimus and “Ca. Nitrosoarchaeum koreensis,” and the repertoire of genes required for ammonia oxidation and carbon fixation in thaumarchaeal group I.1a was conserved. A high level of representation of conserved orthologous genes for signal transduction and motility in the noncore genome might be implicated in niche adaptation by strain MY2. On the basis of phenotypic, phylogenetic, and genomic characteristics, we propose the name “Candidatus Nitrosotenuis chungbukensis” for the ammonia-oxidizing archaeal strain MY2. PMID:24705324

  15. Genome Sequence of a Mesophilic Hydrogenotrophic Methanogen Methanocella paludicola, the First Cultivated Representative of the Order Methanocellales

    PubMed Central

    Sakai, Sanae; Takaki, Yoshihiro; Shimamura, Shigeru; Sekine, Mitsuo; Tajima, Takahisa; Kosugi, Hiroki; Ichikawa, Natsuko; Tasumi, Eiji; Hiraki, Aiko T.; Shimizu, Ai; Kato, Yumiko; Nishiko, Rika; Mori, Koji; Fujita, Nobuyuki; Imachi, Hiroyuki; Takai, Ken

    2011-01-01

    We report complete genome sequence of a mesophilic hydrogenotrophic methanogen Methanocella paludicola, the first cultured representative of the order Methanocellales once recognized as an uncultured key archaeal group for methane emission in rice fields. The genome sequence of M. paludicola consists of a single circular chromosome of 2,957,635 bp containing 3004 protein-coding sequences (CDS). Genes for most of the functions known in the methanogenic archaea were identified, e.g. a full complement of hydrogenases and methanogenesis enzymes. The mixotrophic growth of M. paludicola was clarified by the genomic characterization and re-examined by the subsequent growth experiments. Comparative genome analysis with the previously reported genome sequence of RC-IMRE50, which was metagenomically reconstructed, demonstrated that about 70% of M. paludicola CDSs were genetically related with RC-IMRE50 CDSs. These CDSs included the genes involved in hydrogenotrophic methane production, incomplete TCA cycle, assimilatory sulfate reduction and so on. However, the genetic components for the carbon and nitrogen fixation and antioxidant system were different between the two Methanocellales genomes. The difference is likely associated with the physiological variability between M. paludicola and RC-IMRE50, further suggesting the genomic and physiological diversity of the Methanocellales methanogens. Comparative genome analysis among the previously determined methanogen genomes points to the genome-wide relatedness of the Methanocellales methanogens to the orders Methanosarcinales and Methanomicrobiales methanogens in terms of the genetic repertoire. Meanwhile, the unique evolutionary history of the Methanocellales methanogens is also traced in an aspect by the comparative genome analysis among the methanogens. PMID:21829548

  16. Flexible bacterial strains that oxidize arsenite in anoxic or aerobic conditions and utilize hydrogen or acetate as alternative electron donors

    PubMed Central

    Rodríguez-Freire, Lucía; Sun, Wenjie; Sierra-Alvarez, Reyes; Field, Jim A.

    2013-01-01

    Arsenic is a carcinogenic compound widely distributed in the groundwater around the world. The fate of arsenic in groundwater depends on the activity of microorganisms either by oxidizing arsenite (AsIII), or by reducing arsenate (AsV). Because of the higher toxicity and mobility of AsIII compared to AsV, microbial-catalyzed oxidation of AsIII to AsV can lower the environmental impact of arsenic. Although aerobic AsIII-oxidizing bacteria are well known, anoxic oxidation of AsIII with nitrate as electron acceptor has also been shown to occur. In this study, three AsIII-oxidizing bacterial strains, Azoarcus sp. strain EC1, Azoarcus sp. strain EC3and Diaphorobacter sp. strain MC, have been characterized. Each strain was tested for its ability to oxidize AsIII with four different electron acceptors, nitrate, nitrite, chlorate and oxygen. Complete AsIII oxidation was achieved with both nitrate and oxygen, demonstrating the novel ability of these bacterial strains to oxidize AsIII in either anoxic or aerobic conditions. Nitrate was only reduced to nitrite. Different electron donors were used to study their suitability in supporting nitrate reduction. Hydrogen and acetate were readily utilized by all the cultures. The flexibility of these AsIII-oxidizing bacteria to use oxygen and nitrate to oxidize AsIII as well as organic and inorganic substrates as alternative electron donors explains their presence in non-arsenic-contaminated environments. The findings suggest that at least some AsIII-oxidizing bacteria are flexible with respect to electron-acceptors and electron-donors and that they are potentially widespread in low arsenic concentration environments. PMID:21706372

  17. Hydrogen-Isotopic Systematics of Lipid Biosynthesis in Hydrogen-Consuming Anaerobes and Aerobes

    NASA Astrophysics Data System (ADS)

    Campbell, B. J.; Fox, D.; Valentine, D. L.; Sessions, A. L.

    2004-12-01

    In anoxic sediments, molecular hydrogen (H2) is a key intermediate in the transfer of electrons between H2-producing (e.g., fermentative) bacteria and H2-consuming microbes, including sulfate-reducing bacteria (SRB). H2 is a potential source of lipid-bound hydrogen for SRB, as are water and organic matter. Relative to these other potential sources, H2 typically is markedly depleted in deuterium. If hydrogen from strongly D-depleted H2 is incorporated into SRB lipids, the isotopic signal could be preserved over geologic time in biomarker compounds in the sediments. The accumulation of characteristically D-depleted SRB biomarkers may thus provide a quantitative measure of sulfate reduction (and hence of carbon remineralization by SRB) in the ancient environment. Ongoing experiments are designed to quantify the relative contributions of H2, water, and organic matter to lipid-bound hydrogen in SRB, as well as to determine the associated hydrogen-isotopic fractionations. Desulfobacterium autotrophicum, a facultative autotroph, is grown in pure culture under various isotopically defined conditions. Water in the media and key metabolites are monitored for D/H. The produced biomass is harvested, and D/H ratios of individual lipid compounds are measured. Isotopic mass-balance calculations based on these data will allow us to determine 1) hydrogen-isotopic compositions of SRB lipids, 2) effects of growth conditions on D/H ratios, and 3) the biochemical sources for lipid-bound hydrogen. Similar experiments are underway to identify and quantify the controls on stable hydrogen-isotopic fractionation during lipid biosynthesis in syntrophic cocultures and in pure cultures of H2-consuming, aerobic (i.e., knallgas) bacteria. Taken together, these experiments will provide a first test of our hypothesis that D/H ratios in lipids can be used to quantify carbon remineralization by SRB in modern, and potentially ancient, sediments.

  18. STORMWATER MANAGEMENT MEASURES AND FECAL INDICATOR BACTERIA

    E-print Network

    STORMWATER MANAGEMENT MEASURES AND FECAL INDICATOR BACTERIA BY ROBERT A. WILDEY BA, New College............................................................................................................. 1 Regulatory Limits for Indicator Bacteria................................................................ 2 Indicator Bacteria in the Environment

  19. Inferring the palaeoenvironment of ancient bacteria on the basis of resurrected proteins

    NASA Technical Reports Server (NTRS)

    Gaucher, Eric A.; Thomson, J. Michael; Burgan, Michelle F.; Benner, Steven A.

    2003-01-01

    Features of the physical environment surrounding an ancestral organism can be inferred by reconstructing sequences of ancient proteins made by those organisms, resurrecting these proteins in the laboratory, and measuring their properties. Here, we resurrect candidate sequences for elongation factors of the Tu family (EF-Tu) found at ancient nodes in the bacterial evolutionary tree, and measure their activities as a function of temperature. The ancient EF-Tu proteins have temperature optima of 55-65 degrees C. This value seems to be robust with respect to uncertainties in the ancestral reconstruction. This suggests that the ancient bacteria that hosted these particular genes were thermophiles, and neither hyperthermophiles nor mesophiles. This conclusion can be compared and contrasted with inferences drawn from an analysis of the lengths of branches in trees joining proteins from contemporary bacteria, the distribution of thermophily in derived bacterial lineages, the inferred G + C content of ancient ribosomal RNA, and the geological record combined with assumptions concerning molecular clocks. The study illustrates the use of experimental palaeobiochemistry and assumptions about deep phylogenetic relationships between bacteria to explore the character of ancient life.

  20. Inferring the palaeoenvironment of ancient bacteria on the basis of resurrected proteins.

    PubMed

    Gaucher, Eric A; Thomson, J Michael; Burgan, Michelle F; Benner, Steven A

    2003-09-18

    Features of the physical environment surrounding an ancestral organism can be inferred by reconstructing sequences of ancient proteins made by those organisms, resurrecting these proteins in the laboratory, and measuring their properties. Here, we resurrect candidate sequences for elongation factors of the Tu family (EF-Tu) found at ancient nodes in the bacterial evolutionary tree, and measure their activities as a function of temperature. The ancient EF-Tu proteins have temperature optima of 55-65 degrees C. This value seems to be robust with respect to uncertainties in the ancestral reconstruction. This suggests that the ancient bacteria that hosted these particular genes were thermophiles, and neither hyperthermophiles nor mesophiles. This conclusion can be compared and contrasted with inferences drawn from an analysis of the lengths of branches in trees joining proteins from contemporary bacteria, the distribution of thermophily in derived bacterial lineages, the inferred G + C content of ancient ribosomal RNA, and the geological record combined with assumptions concerning molecular clocks. The study illustrates the use of experimental palaeobiochemistry and assumptions about deep phylogenetic relationships between bacteria to explore the character of ancient life. PMID:13679914

  1. Recurrent isolation of extremotolerant bacteria from the clean room where Phoenix spacecraft components were assembled.

    PubMed

    Ghosh, Sudeshna; Osman, Shariff; Vaishampayan, Parag; Venkateswaran, Kasthuri

    2010-04-01

    The microbial burden of the Phoenix spacecraft assembly environment was assessed in a systematic manner via several cultivation-based techniques and a suite of NASA-certified, cultivation-independent biomolecule-based detection assays. Extremotolerant bacteria that could potentially survive conditions experienced en route to Mars or on the planet's surface were isolated with a series of cultivation-based assays that promoted the growth of a variety of organisms, including spore formers, mesophilic heterotrophs, anaerobes, thermophiles, psychrophiles, alkaliphiles, and bacteria resistant to UVC radiation and hydrogen peroxide exposure. Samples were collected from the clean room where Phoenix was housed at three different time points, before (1P), during (2P), and after (3P) Phoenix's presence at the facility. There was a reduction in microbial burden of most bacterial groups, including spore formers, in samples 2P and 3P. Analysis of 262 isolates from the facility demonstrated that there was also a shift in predominant cultivable bacterial populations accompanied by a reduction in diversity during 2P and 3P. It is suggested that this shift was a result of increased cleaning when Phoenix was present in the assembly facility and that certain species, such as Acinetobacter johnsonii and Brevundimonas diminuta, may be better adapted to environmental conditions found during 2P and 3P. In addition, problematic bacteria resistant to multiple extreme conditions, such as Bacillus pumilus, were able to survive these periods of increased cleaning. PMID:20446872

  2. Aerobic biological activated carbon (BAC) treatment of a phenolic wastewater

    SciTech Connect

    Wei Lin; Weber, A.S. )

    1992-05-01

    Organic removal rates achieved in the aerobic BAC process were comparable to rates typically reported for traditional aerobic fixed-film systems. When operated at organic loading rates lower than 0.03 g COD/g GAC-d and air as the oxygen source, greater than 90% COD removal and 99% phenol removal was achieved. At higher organic loading rates, oxygen limitations resulted in less than optimal performance. Observed oxygen limitations were mitigated by the use of pure oxygen. Long-term stability of operation of the BAC process was excellent with one aerobic BAC column operated under the same conditions in excess of 260 days. During that time, consistent column performance was achieved without the need to provide supplemental carbon or carbon regeneration. System biomass yields ranged from 0.05 to 0.30 g VSS/g COD removed and increased with effluent COD concentration.

  3. Aerobic and Anaerobic Transformations of Pentachlorophenol in Wetland Soils Elisa M. D'Angelo* and K. R. Reddy

    E-print Network

    Florida, University of

    Aerobic and Anaerobic Transformations of Pentachlorophenol in Wetland Soils Elisa M. D concentrations 6 \\iM to >23 \\s,M (aerobic conditions). Differences of microbial groups. Within this concentra- tion range, transformation was observed in soils under aerobic

  4. News and Research Good Bacteria

    E-print Network

    West, Stuart

    News and Research Good Bacteria Part 2 Article 13 Click here for Probiotics Basics Cooperation Is A No-brainer For Symbiotic Bacteria 9-4-2003 Humans may learn cooperation in kindergarten, but what about bacteria, whose behavior is preprogrammed by their DNA? Some legume plants, which rely

  5. Fermentation Characteristics and Lactic Acid Bacteria Succession of Total Mixed Ration Silages Formulated with Peach Pomace

    PubMed Central

    Hu, Xiaodong; Hao, Wei; Wang, Huili; Ning, Tingting; Zheng, Mingli; Xu, Chuncheng

    2015-01-01

    The objective of this study was to assess the use of peach pomace in total mixed ration (TMR) silages and clarify the differences in aerobic stability between TMR and TMR silages caused by lactic acid bacteria (LAB). The TMR were prepared using peach pomace, alfalfa hay or Leymus chinensis hay, maize meal, soybean meal, cotton meal, limestone, a vitamin-mineral supplement, and salt in a ratio of 6.0:34.0:44.4:7.0:5.0:2.5:1.0:0.1 on a dry matter (DM) basis. Fermentation quality, microbial composition, and the predominant LAB were examined during ensiling and aerobic deterioration. The results indicated that the TMR silages with peach pomace were well fermented, with low pH and high lactic acid concentrations. The aerobic stability of TMR silages were significantly higher than that of TMR. Compared with TMR silages with alfalfa hay, TMR silage with Leymus chinensis hay was much more prone to deterioration. Although the dominant LAB were not identical in TMR, the same dominant species, Lactobacillus buchneri and Pediococcus acidilactici, were found in both types of TMR silages after 56 d of ensiling, and they may play an important role in the aerobic stability of TMR silages. PMID:25656205

  6. Lipoprotein sorting in bacteria.

    PubMed

    Okuda, Suguru; Tokuda, Hajime

    2011-01-01

    Bacterial lipoproteins are synthesized as precursors in the cytoplasm and processed into mature forms on the cytoplasmic membrane. A lipid moiety attached to the N terminus anchors these proteins to the membrane surface. Many bacteria are predicted to express more than 100 lipoproteins, which play diverse functions on the cell surface. The Lol system, composed of five proteins, catalyzes the localization of Escherichia coli lipoproteins to the outer membrane. Some lipoproteins play vital roles in the sorting of other lipoproteins, lipopolysaccharides, and ?-barrel proteins to the outer membrane. On the basis of results from biochemical, genetic, and structural studies, we discuss the biogenesis of lipoproteins in bacteria, their importance in cellular functions, and the molecular mechanisms underlying efficient sorting of hydrophobic lipoproteins to the outer membrane through the hydrophilic periplasm. PMID:21663440

  7. Manufacture of Probiotic Bacteria

    NASA Astrophysics Data System (ADS)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  8. Reanimation of Ancient Bacteria

    SciTech Connect

    Vreeland, Russell H.

    2009-01-09

    Recent highly publicized experiments conducted on salt crystals taken from the Permian Salado Formation in Southeastern New Mexico have shown that some ancient crystals contain viable microorganisms trapped within fluid inclusions. Stringent geological and microbiological selection criteria were used to select crystals and conduct all sampling. This talk will focus on how each of these lines of data support the conclusion that such isolated bacteria are as old as the rock in which they are trapped. In this case, the isolated microbes are salt tolerant bacilli that grow best in media containing 8% NaCl, and respond to concentrated brines by forming spores. One of the organisms is phylogenetically related to several bacilli, but does have several unique characteristics. This talk will trace the interdisciplinary data and procedures supporting these discoveries, and describe the various isolated bacteria.

  9. Chemical characterization of some aerobic liquids in CELSS

    NASA Technical Reports Server (NTRS)

    Madsen, Brooks C.

    1993-01-01

    Untreated aqueous soybean and wheat leachate and aerobically treated wheat leachate prepared from crop residues that are produced as a component of the Controlled Ecological Life Support System program designed to support long duration space missions were compared, and a general chemical characterization was accomplished. Solid phase extraction and high performance liquid chromatography were used to accomplish comparisons based on chromatographic and ultraviolet absorption properties of the components that are present. Specific compounds were not identified; however, general composition related to the initial presence of phenol-like compounds and their disappearance during aerobic treatment was explored.

  10. Aerobic Development of Elite Youth Ice Hockey Players.

    PubMed

    Leiter, Jeff R; Cordingley, Dean M; MacDonald, Peter B

    2015-11-01

    Leiter, JR, Cordingley, DM, and MacDonald, PB. Aerobic development of elite youth ice hockey players. J Strength Cond Res 29(11): 3223-3228, 2015-Ice hockey is a physiologically complex sport requiring aerobic and anaerobic energy metabolism. College and professional teams often test aerobic fitness; however, there is a paucity of information regarding aerobic fitness of elite youth players. Without this knowledge, training of youth athletes to meet the standards of older age groups and higher levels of hockey may be random, inefficient, and or effective. Therefore, the purpose of this study was to determine the aerobic fitness of elite youth hockey players. A retrospective database review was performed for 200 male AAA hockey players between the ages of 13 and 17 (age, 14.4 ± 1.2 years; height, 174.3 ± 8.5 cm; body mass, 67.2 ± 11.5 kg; body fat, 9.8 ± 3.5%) before the 2012-13 season. All subjects performed a graded exercise test on a cycle ergometer, whereas expired air was collected by either a Parvo Medics TrueOne 2400 or a CareFusion Oxycon Mobile metabolic cart to determine maximal oxygen consumption (V[Combining Dot Above]O2max). Body mass, absolute V[Combining Dot Above]O2max, and the power output achieved during the last completed stage increased in successive age groups from age 13 to 15 years (p ? 0.05). Ventilatory threshold (VT) expressed as a percentage of V[Combining Dot Above]O2max and the heart rate (HR) at which VT occurred decreased between the ages of 13 and 14 years (p ? 0.05), whereas the V[Combining Dot Above]O2 at which VT occurred increased from the age of 14-15 years. There were no changes in relative V[Combining Dot Above]O2max or HRmax between any successive age groups. The aerobic fitness levels of elite youth ice hockey players increased as players age and mature physically and physiologically. However, aerobic fitness increased to a lesser extent at older ages. This information has the potential to influence off-season training and maximize the aerobic fitness of elite amateur hockey players, so that these players can meet standards set by advanced elite age groups. PMID:26506063

  11. Stimulating in situ denitrification in an aerobic, highly permeable municipal drinking water aquifer.

    PubMed

    Critchley, K; Rudolph, D L; Devlin, J F; Schillig, P C

    2014-12-15

    A preliminary trial of a cross-injection system (CIS) was designed to stimulate in situ denitrification in an aquifer servicing an urban community in southern Ontario. It was hypothesized that this remedial strategy could be used to reduce groundwater nitrate in the aquifer such that it could remain in use as a municipal supply until the beneficial effects of local reduced nutrient loadings lead to long-term water quality improvement at the wellfield. The CIS application involved injecting a carbon source (acetate) into the subsurface using an injection-extraction well pair positioned perpendicular to the regional flow direction, up-gradient of the water supply wells, with the objective of stimulating native denitrifying bacteria. The pilot remedial strategy was targeted in a high nitrate flux zone within an aerobic and heterogeneous section of the glacial sand and gravel aquifer. Acetate injections were performed at intervals ranging from daily to bi-daily. The carbon additions led to general declines in dissolved oxygen concentrations; decreases in nitrate concentration were localized in aquifer layers where velocities were estimated to be less than 0.5m/day. NO3-(15)N and NO3-(18)O isotope data indicated the nitrate losses were due to denitrification. Relatively little nitrate was removed from groundwater in the more permeable strata, where velocities were estimated to be on the order of 18 m/day or greater. Overall, about 11 percent of the nitrate mass passing through the treatment zone was removed. This work demonstrates that stimulating in situ denitrification in an aerobic, highly conductive aquifer is challenging but achievable. Further work is needed to increase rates of denitrification in the most permeable units of the aquifer. PMID:25461888

  12. Toxinogenic and spoilage potential of aerobic spore-formers isolated from raw milk.

    PubMed

    De Jonghe, Valerie; Coorevits, An; De Block, Jan; Van Coillie, Els; Grijspeerdt, Koen; Herman, Lieve; De Vos, Paul; Heyndrickx, Marc

    2010-01-01

    The harmful effects on the quality and safety of dairy products caused by aerobic spore-forming isolates obtained from raw milk were characterized. Quantitative assessment showed strains of Bacillus subtilis, the Bacillus cereus group, Paenibacillus polymyxa and Bacillus amyloliquefaciens to be strongly proteolytic, along with Bacillus licheniformis, Bacillus pumilus and Lysinibacillus fusiformis to a lesser extent. Lipolytic activity could be demonstrated in strains of B. subtilis, B. pumilus and B. amyloliquefaciens. Qualitative screening for lecithinase activity also revealed that P. polymyxa strains produce this enzyme besides the B. cereus group that is well-known for causing a 'bitty cream' defect in pasteurized milk due to lecithinase activity. We found a strain of P. polymyxa to be capable of gas production during lactose fermentation. Strains belonging to the species B. amyloliquefaciens, Bacillus clausii, Lysinibacillus sphaericus, B. subtilis and P. polymyxa were able to reduce nitrate. A heat-stable cytotoxic component other than the emetic toxin was produced by strains of B. amyloliquefaciens and B. subtilis. Heat-labile cytotoxic substances were produced by strains identified as B. amyloliquefaciens, B. subtilis, B. pumilus and the B. cereus group. Variations in expression levels between strains from the same species were noticed for all tests. This study emphasizes the importance of aerobic spore-forming bacteria in raw milk as the species that are able to produce toxins and/or spoilage enzymes are all abundantly present in raw milk. Moreover, we demonstrated that some strains are capable of growing at room temperature and staying stable at refrigeration temperatures. PMID:19944473

  13. Degradation of vinyl acetate by soil, sewage, sludge, and the newly isolated aerobic bacterium V2.

    PubMed Central

    Nieder, M; Sunarko, B; Meyer, O

    1990-01-01

    Vinyl acetate is subject to microbial degradation in the environment and by pure cultures. It was hydrolyzed by samples of soil, sludge, and sewage at rates of up to 6.38 and 1 mmol/h per g (dry weight) under aerobic and anaerobic conditions, respectively. Four yeasts and thirteen bacteria that feed aerobically on vinyl acetate were isolated. The pathway of vinyl acetate degradation was studied in bacterium V2. Vinyl acetate was degraded to acetate as follows: vinyl acetate + NAD(P)+----2 acetate + NAD(P)H + H+. The acetate was then converted to acetyl coenzyme A and oxidized through the tricarboxylic acid cycle and the glyoxylate bypass. The key enzyme of the pathway is vinyl acetate esterase, which hydrolyzed the ester to acetate and vinyl alcohol. The latter isomerized spontaneously to acetaldehyde and was then converted to acetate. The acetaldehyde was disproportionated into ethanol and acetate. The enzymes involved in the metabolism of vinyl acetate were studied in extracts. Vinyl acetate esterase (Km = 6.13 mM) was also active with indoxyl acetate (Km = 0.98 mM), providing the basis for a convenient spectrophotometric test. Substrates of aldehyde dehydrogenase were formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde. The enzyme was equally active with NAD+ or NADP+. Alcohol dehydrogenase was active with ethanol (Km = 0.24 mM), 1-propanol (Km = 0.34 mM), and 1-butanol (Km = 0.16 mM) and was linked to NAD+. The molecular sizes of aldehyde dehydrogenase and alcohol dehydrogenase were 145 and 215 kilodaltons, respectively. PMID:2285314

  14. Stimulating in situ denitrification in an aerobic, highly permeable municipal drinking water aquifer

    NASA Astrophysics Data System (ADS)

    Critchley, K.; Rudolph, D. L.; Devlin, J. F.; Schillig, P. C.

    2014-12-01

    A preliminary trial of a cross-injection system (CIS) was designed to stimulate in situ denitrification in an aquifer servicing an urban community in southern Ontario. It was hypothesized that this remedial strategy could be used to reduce groundwater nitrate in the aquifer such that it could remain in use as a municipal supply until the beneficial effects of local reduced nutrient loadings lead to long-term water quality improvement at the wellfield. The CIS application involved injecting a carbon source (acetate) into the subsurface using an injection-extraction well pair positioned perpendicular to the regional flow direction, up-gradient of the water supply wells, with the objective of stimulating native denitrifying bacteria. The pilot remedial strategy was targeted in a high nitrate flux zone within an aerobic and heterogeneous section of the glacial sand and gravel aquifer. Acetate injections were performed at intervals ranging from daily to bi-daily. The carbon additions led to general declines in dissolved oxygen concentrations; decreases in nitrate concentration were localized in aquifer layers where velocities were estimated to be less than 0.5 m/day. NO3-15N and NO3-18O isotope data indicated the nitrate losses were due to denitrification. Relatively little nitrate was removed from groundwater in the more permeable strata, where velocities were estimated to be on the order of 18 m/day or greater. Overall, about 11 percent of the nitrate mass passing through the treatment zone was removed. This work demonstrates that stimulating in situ denitrification in an aerobic, highly conductive aquifer is challenging but achievable. Further work is needed to increase rates of denitrification in the most permeable units of the aquifer.

  15. Siboglinid-bacteria endosymbiosis

    PubMed Central

    Fielman, Kevin T; Santos, Scott R; Halanych, Kenneth M

    2008-01-01

    Siboglinid worms are a group of gutless marine annelids which are nutritionally dependent upon endosymbiotic bacteria.1,2 Four major groups of siboglinids are known including vestimentiferans, Osedax spp., frenulates and moniliferans.3–5 Very little is known about the diversity of bacterial endosymbionts associated with frenulate or monoliferan siboglinids. This lack of knowledge is surprising considering the global distribution of siboglinids; this system is likely among the most common symbioses in the deep sea. At least three distinct clades of endosymbiotic ?-proteobacteria associate with siboglinid annelids.6 Frenulates harbor a clade of ?-proteobacteria that are divergent from both the thiotrophic bacteria of vestimentiferans and monoliferans as well as the heterotrophic bacteria of Osedax spp.6,7 We also discuss priorities for future siboglinid research and the need to move beyond descriptive studies. A promising new method, laser-capture microdissection (LCM), allows for the precise excision of tissue regions of interest.8 This method, when used in concert with molecular and genomic techniques, such as Expressed Sequence Tag (EST) surveys using pyrosequencing technology, will likely enable investigations into physiological processes and mechanisms in these symbioses. Furthermore, adopting a comparative approach using different siboglinid groups, such as worms harboring thiotrophic versus methanotrophic endosymbionts, may yield considerable insight into the ecology and evolution of the Siboglinidae. PMID:19704881

  16. Acetic acid bacteria spoilage of bottled red wine -- a review.

    PubMed

    Bartowsky, Eveline J; Henschke, Paul A

    2008-06-30

    Acetic acid bacteria (AAB) are ubiquitous organisms that are well adapted to sugar and ethanol rich environments. This family of Gram-positive bacteria are well known for their ability to produce acetic acid, the main constituent in vinegar. The oxidation of ethanol through acetaldehyde to acetic acid is well understood and characterised. AAB form part of the complex natural microbial flora of grapes and wine, however their presence is less desirable than the lactic acid bacteria and yeast. Even though AAB were described by Pasteur in the 1850s, wine associated AAB are still difficult to cultivate on artificial laboratory media and until more recently, their taxonomy has not been well characterised. Wine is at most risk of spoilage during production and the presence of these strictly aerobic bacteria in grape must and during wine maturation can be controlled by eliminating, or at least limiting oxygen, an essential growth factor. However, a new risk, spoilage of wine by AAB after packaging, has only recently been reported. As wine is not always sterile filtered prior to bottling, especially red wine, it often has a small resident bacterial population (<10(3) cfu/mL), which under conducive conditions might proliferate. Bottled red wines, sealed with natural cork closures, and stored in a vertical upright position may develop spoilage by acetic acid bacteria. This spoilage is evident as a distinct deposit of bacterial biofilm in the neck of the bottle at the interface of the wine and the headspace of air, and is accompanied with vinegar, sherry, bruised apple, nutty, and solvent like off-aromas, depending on the degree of spoilage. This review focuses on the wine associated AAB species, the aroma and flavour changes in wine due to AAB metabolism, discusses the importance of oxygen ingress into the bottle and presents a hypothesis for the mechanism of spoilage of bottled red wine. PMID:18237809

  17. Bacteria on Catheters in Patients Undergoing Peritoneal Dialysis

    PubMed Central

    Pihl, Maria; Davies, Julia R.; Johansson, Ann-Cathrine; Svensäter, Gunnel

    2013-01-01

    ? Background: Peritonitis is the leading cause of morbidity for peritoneal dialysis (PD) patients, and microbial biofilms have previously been identified on catheters from infected patients. However, few studies of catheters from patients without clinical signs of infection have been undertaken. The aim of the present study was to investigate the extent to which bacteria are present on catheters from PD patients with no symptoms of infection. ? Methods: Microbiologic culturing under aerobic and anaerobic conditions and confocal laser scanning microscopy were used to determine the distribution of bacteria on PD catheters from 15 patients without clinical signs of infection and on catheters from 2 infected patients. The 16S rRNA gene sequencing technique was used to identify cultured bacteria. ? Results: Bacteria were detected on 12 of the 15 catheters from patients without signs of infection and on the 2 catheters from infected patients. Single-species and mixed-microbial communities containing up to 5 species were present on both the inside and the outside along the whole length of the colonized catheters. The bacterial species most commonly found were the skin commensals Staphylococcus epidermidis and Propionibacterium acnes, followed by S. warneri and S. lugdunensis. The strains of these micro-organisms, particularly those of S. epidermidis, varied in phenotype with respect to their tolerance of the major classes of antibiotics. ? Conclusions: Bacteria were common on catheters from patients without symptoms of infection. Up to 4 different bacterial species were found in close association and may represent a risk factor for the future development of peritonitis in patients hosting such micro-organisms. PMID:22855889

  18. Correlation between microbial flora, sensory changes and biogenic amines formation in fresh chicken meat stored aerobically or under modified atmosphere packaging at 4 degrees C: possible role of biogenic amines as spoilage indicators.

    PubMed

    Balamatsia, C C; Paleologos, E K; Kontominas, M G; Savvaidis, I N

    2006-01-01

    This study evaluated the formation of biogenic amines (BAs) in breast chicken meat during storage under aerobic and modified atmospheric packaging (MAP) conditions at 4 degrees C, the correlation of microbial and sensory changes in chicken meat with formation of BAs and the possible role of BAs as indicators of poultry meat spoilage. Poultry breast fillets were stored aerobically or under MAP (30%, CO(2), 70% N(2)) at 4 degrees C for up to 17 days. Quality evaluation was carried out using microbiological, chemical and sensory analyses. Total viable counts, Pseudomonads and Enterobacteriaceae, were in general higher for chicken samples packaged in air whereas lactic acid bacteria (LAB) and Enterobacteriaceae were among the dominant species for samples under MAP. Levels of putrescine and cadaverine increased linearly with storage time and were higher in aerobically stored chicken samples. Spermine and spermidine levels were also detected in both aerobically and MAP stored chicken meat. Levels of tyramine in both chicken samples stored aerobically and or under MAP were low (< 10 mg kg(-1)) whereas the formation of histamine was only observed after day 11 of storage when Enterobacteriaceae had reached a population of ca. 10(7) CFU g(-1). Based on sensory and microbiological analyses and also taking into account a biogenic amines index (BAI, sum of putrescine, cadaverine and tyramine), BAI values between 96 and 101 mg kg(-1) may be proposed as a quality index of MAP and aerobically-packaged fresh chicken meat. Spermine and spermidine decreased steadily throughout the entire storage period of chicken meat under aerobic and MAP packaging, and thus these two amines cannot be used as indicators of fresh chicken meat quality. PMID:16528580

  19. ENGINEERING AND ECONOMIC ASSESSMENT OF AUTOHEATED THERMOPHILIC AEROBIC DIGESTION WITH AIR AERATION

    EPA Science Inventory

    A major disadvantage of aerobic digestion is that it requires long detention times, particularly in colder climates, to insure adequate stabilization. Autoheated thermophilic aerobic digestion (ATAD) offers the potential to decrease the required detention time. ATAD takes advanta...

  20. ENVIRONMENTAL REGULATIONS AND TECHNOLOGY - AUTOTHERMAL THERMOPHILIC AEROBIC DIGESTION OF MUNICIPAL WASTEWATER SLUDGE

    EPA Science Inventory

    This document describes a promising technology — autothermal thermophilic aerobic digestion — for meeting the current and proposed U.S. federal requirements for pathogen controJ and land application of municipal wastewater sludge. Autothermal thermophilic aerobic digestion, or AT...

  1. Trade-off between aerobic capacity and locomotor capability in an Antarctic pteropod

    E-print Network

    Bezanilla, Francisco

    Trade-off between aerobic capacity and locomotor capability in an Antarctic pteropod Joshua J. C investigation on neuromuscular adaptation to the extreme cold. We find that for the Antarctic congener aerobic

  2. Constant Growth Rate Can Be Supported by Decreasing Energy Flux and Increasing Aerobic Glycolysis

    E-print Network

    Slavov, Nikolai

    Fermenting glucose in the presence of enough oxygen to support respiration, known as aerobic glycolysis, is believed to maximize growth rate. We observed increasing aerobic glycolysis during exponential growth, suggesting ...

  3. Gut bacteria mediate aggregation in the German cockroach.

    PubMed

    Wada-Katsumata, Ayako; Zurek, Ludek; Nalyanya, Godfrey; Roelofs, Wendell L; Zhang, Aijun; Schal, Coby

    2015-12-22

    Aggregation of the German cockroach, Blattella germanica, is regulated by fecal aggregation agents (pheromones), including volatile carboxylic acids (VCAs). We demonstrate that the gut microbial community contributes to production of these semiochemicals. Chemical analysis of the fecal extract of B. germanica revealed 40 VCAs. Feces from axenic cockroaches (no microorganisms in the alimentary tract) lacked 12 major fecal VCAs, and 24 of the remaining compounds were represented at extremely low amounts. Olfactory and aggregation bioassays demonstrated that nymphs strongly preferred the extract of control feces over the fecal extract of axenic cockroaches. Additionally, nymphs preferred a synthetic blend of 6 fecal VCAs over a solvent control or a previously identified VCA blend. To test whether gut bacteria contribute to the production of fecal aggregation agents, fecal aerobic bacteria were cultured, isolated, and identified. Inoculation of axenic cockroaches with individual bacterial taxa significantly rescued the aggregation response to the fecal extract, and inoculation with a mix of six bacterial isolates was more effective than with single isolates. The results indicate that the commensal gut microbiota contributes to production of VCAs that act as fecal aggregation agents and that cockroaches discriminate among the complex odors that emanate from a diverse microbial community. Our results highlight the pivotal role of gut bacteria in mediating insect-insect communication. Moreover, because the gut microbial community reflects the local environment, local plasticity in fecal aggregation pheromones enables colony-specific odors and fidelity to persistent aggregation sites. PMID:26644557

  4. Gut bacteria mediate aggregation in the German cockroach

    PubMed Central

    Wada-Katsumata, Ayako; Zurek, Ludek; Nalyanya, Godfrey; Roelofs, Wendell L.; Zhang, Aijun; Schal, Coby

    2015-01-01

    Aggregation of the German cockroach, Blattella germanica, is regulated by fecal aggregation agents (pheromones), including volatile carboxylic acids (VCAs). We demonstrate that the gut microbial community contributes to production of these semiochemicals. Chemical analysis of the fecal extract of B. germanica revealed 40 VCAs. Feces from axenic cockroaches (no microorganisms in the alimentary tract) lacked 12 major fecal VCAs, and 24 of the remaining compounds were represented at extremely low amounts. Olfactory and aggregation bioassays demonstrated that nymphs strongly preferred the extract of control feces over the fecal extract of axenic cockroaches. Additionally, nymphs preferred a synthetic blend of 6 fecal VCAs over a solvent control or a previously identified VCA blend. To test whether gut bacteria contribute to the production of fecal aggregation agents, fecal aerobic bacteria were cultured, isolated, and identified. Inoculation of axenic cockroaches with individual bacterial taxa significantly rescued the aggregation response to the fecal extract, and inoculation with a mix of six bacterial isolates was more effective than with single isolates. The results indicate that the commensal gut microbiota contributes to production of VCAs that act as fecal aggregation agents and that cockroaches discriminate among the complex odors that emanate from a diverse microbial community. Our results highlight the pivotal role of gut bacteria in mediating insect–insect communication. Moreover, because the gut microbial community reflects the local environment, local plasticity in fecal aggregation pheromones enables colony-specific odors and fidelity to persistent aggregation sites. PMID:26644557

  5. Polyhydroxyalkanoate production potential of heterotrophic bacteria in activated sludge.

    PubMed

    Inoue, Daisuke; Suzuki, Yuta; Uchida, Takahiro; Morohoshi, Jota; Sei, Kazunari

    2016-01-01

    This study was conducted to evaluate the polyhydroxyalkanoate (PHA) production potential of cultivable heterotrophic bacteria in activated sludge by genotypic and phenotypic characterizations. A total of 114 bacterial strains were isolated from four activated sludge samples taken from a lab-scale sequencing batch reactor and three wastewater treatment processes of two municipal wastewater treatment plants. PCR detection of the phaC genes encoding class I and II PHA synthase revealed that 15% of the total isolates possessed phaC genes, all of which had the closest similarities to known phaC genes of ?- and ?-Proteobacteria and Actinobacteria. PHA production experiments under aerobic and nitrogen-limited conditions showed that 68% of the total isolates were capable of producing PHA from at least one of the six substrates used (acetate, propionate, lactate, butyrate, glucose and glycerol). Genotypic and phenotypic characterizations revealed that 75% of the activated sludge bacteria had PHA production potential. Our results also indicated that short-chain fatty acids would be the preferable substrates for PHA production by activated sludge bacteria, and that there might be a variety of unidentified phaC genes in activated sludge. PMID:26071670

  6. Predatory prokaryotes: predation and primary consumption evolved in bacteria

    NASA Technical Reports Server (NTRS)

    Guerrero, R.; Pedros-Alio, C.; Esteve, I.; Mas, J.; Chase, D.; Margulis, L.

    1986-01-01

    Two kinds of predatory bacteria have been observed and characterized by light and electron microscopy in samples from freshwater sulfurous lakes in northeastern Spain. The first bacterium, named Vampirococcus, is Gram-negative and ovoidal (0.6 micrometer wide). An anaerobic epibiont, it adheres to the surface of phototrophic bacteria (Chromatium spp.) by specific attachment structures and, as it grows and divides by fission, destroys its prey. An important in situ predatory role can be inferred for Vampirococcus from direct counts in natural samples. The second bacterium, named Daptobacter, is a Gram-negative, facultatively anaerobic straight rod (0.5 x 1.5 micrometers) with a single polar flagellum, which collides, penetrates, and grows inside the cytoplasm of its prey (several genera of Chromatiaceae). Considering also the well-known case of Bdellovibrio, a Gram-negative, aerobic curved rod that penetrates and divides in the periplasmic space of many chemotrophic Gram-negative bacteria, there are three types of predatory prokaryotes presently known (epibiotic, cytoplasmic, and periplasmic). Thus, we conclude that antagonistic relationships such as primary consumption, predation, and scavenging had already evolved in microbial ecosystems prior to the appearance of eukaryotes. Furthermore, because they represent methods by which prokaryotes can penetrate other prokaryotes in the absence of phagocytosis, these associations can be considered preadaptation for the origin of intracellular organelles.

  7. Characterization and comparative analysis of psychrophilic and mesophilic alpha-amylases from Euplotes species: a contribution to the understanding of enzyme thermal adaptation.

    PubMed

    Yang, Guang; Yang, Guang; Aprile, Lino; Turturo, Vincenzo; Pucciarelli, Sandra; Pucciarelli, Stefania; Miceli, Cristina

    2013-09-01

    The eukaryotic ?-amylase isolated from the psychrophilic ciliated protozoon Euplotes focardii (EfAmy) was expressed in Escherichia coli and biochemically characterized. Its enzymatic activity was compared to that of the homologous protein from the mesophilic congeneric species Euplotes crassus (EcAmy). The comparison of the amino acid composition and the surface residue composition of the two enzymes indicated a preference for tiny residues and the avoidance of charged, aromatic and hydrophobic residues in EfAmy. Our comparative homology modeling study reveals a lack of surface salt bridges, a decreased number of the surface charged residues, decreased hydrogen bonds and bound ions, and a reduction of aromatic-sulfur interactions, cationic-? interactions and disulfide interactions in EfAmy. In contrast, sequence alignment and homology modeling showed five unconserved prolines located on the surface loops of EcAmy. By analyzing amylolytic activity towards soluble starch as the substrate, we determined the temperature and pH dependence, thermostability and kinetic parameters of these two enzymes. We demonstrated that EfAmy shows the characteristics of a psychrophilic ?-amylase, such as the highest hydrolytic activity at low temperatures and high thermolability. In contrast, the EcAmy showed mesophilic characteristics with the highest activity at moderate temperatures and a more than 2-fold increased half-life at 50°C compared to EfAmy. The kcat and KM values of EfAmy were higher than those of the mesophilic EcAmy at all tested temperatures. Furthermore, both EfAmy and EcAmy showed maximum activities at pH 9 and maintained high activities in the presence of surfactants. These results suggest the potential applications of EfAmy and EcAmy as ingredients in detergents for industrial applications. PMID:23916704

  8. Microbial Life at 90 C: the Sulfur Bacteria of Boulder Spring

    PubMed Central

    Brock, T. D.; Brock, M. L.; Bott, T. L.; Edwards, M. R.

    1971-01-01

    The physiology of the bacteria living in Boulder Spring (Yellowstone National Park) at 90 to 93 C was studied with radioactive isotope techniques under conditions approximating natural ones. Cover slips were immersed in the spring; after a fairly even, dense coating of bacteria had developed, these cover slips were incubated with radioactive isotopes under various conditions and then counted in a gas flow or liquid scintillation counter. Uptake of labeled compounds was virtually completely inhibited by formaldehyde, hydrochloric acid, and mercuric bichloride, and inhibition was also found with streptomycin and sodium azide. The water of Boulder Spring contains about 3 ?g of sulfide per ml. Uptake of labeled compounds occurs only if sulfide or another reduced sulfur compound is present during incubation. The pH optimum for uptake of radioactive compounds by Boulder Spring bacteria is 9.2, a value near that of the natural spring water (8.9). Many experiments with a variety of compounds were performed to determine the temperature optimum for uptake of labeled compounds. The results with all the compounds were generally similar, with broad temperature optima between 80 and 90 C, and with significant uptake in boiling (93 C) but not in superheated water (97 C). The results show that the bacteria of Boulder Spring are able to function at the temperature of their environment, although they function better at temperatures somewhat lower. The fine structure of these bacteria has been studied by allowing bacteria in the spring to colonize glass slides or Mylar strips which were immediately fixed, and the bacteria were then embedded and sectioned. The cell envelope structure of these bacteria is quite different from that of other mesophilic or thermophilic bacteria. There is a very distinct plasma membrane, but no morphologically distinct peptidoglycan layer was seen outside of the plasma membrane. Instead, a rather thick diffuse layer was seen, within which a subunit structure was often distinctly visible, and connections frequently occurred between this outer layer and the plasma membrane. The thick outer layer usually consisted of two parts, the outer part of which was sometimes missing. Within the cells, structures resembling ribosomes were seen, and regions lacking electron density which probably contained deoxyribonucleic acid were also visible. Images PMID:4935324

  9. Evaluation of the in-situ aerobic cometabolism of chlorinated ethenes by toluene-utilizing microorganisms

    E-print Network

    Semprini, Lewis

    Evaluation of the in-situ aerobic cometabolism of chlorinated ethenes by toluene by Elsevier B.V. Keywords: Aerobic cometabolism; Single-well push­pull tests; Toluene; ortho-cresol; Isobutene sites have the potential to transform TCE and lesser chlorinated ethenes via aerobic cometabolism

  10. Effect of Aerobic and Anaerobic Conditions on Chlorophenol Sorption in Wetland Soils

    E-print Network

    Florida, University of

    Effect of Aerobic and Anaerobic Conditions on Chlorophenol Sorption in Wetland Soils Elisa D- Much research on organic pollutant sorption has dem-bated under aerobic or anaerobic conditions a strong link between the distribution ratio of aerobic and anaerobic processes on sorption, and (ii

  11. Push-pull test evaluation of the in situ aerobic cometabolism of chlorinated ethenes by

    E-print Network

    Semprini, Lewis

    Push-pull test evaluation of the in situ aerobic cometabolism of chlorinated ethenes by toluene the potential to degrade TCE aerobically and anaerobically (Hopkins et al., 1993). A variety of substrates have been shown to stimu- late aerobic cometabolism of CAHs under laboratory and field conditions (Semprini

  12. Phenotypic flexibility in passerine birds: Seasonal variation of aerobic enzyme activities in skeletal muscle

    E-print Network

    Swanson, David L.

    Phenotypic flexibility in passerine birds: Seasonal variation of aerobic enzyme activities activities of the key aerobic enzymes citrate synthase (CS) and b-hydroxyacyl CoA-dehydrogenase (HOAD and cellular aerobic capacity in muscle contribute to seasonal metabolic flexibility in some species

  13. Role of Aerobic and Anaerobic Circular Mantle Muscle Fibers in Swimming Squid: Electromyography

    E-print Network

    Horth, Lisa

    Role of Aerobic and Anaerobic Circular Mantle Muscle Fibers in Swimming Squid: Electromyography IAN muscle of squids and cuttle- fishes consists of distinct zones of aerobic and anaerobic muscle fibers recorded from electrodes intersecting both the central anaerobic and pe- ripheral aerobic circular mantle

  14. Redox and ATP control of photosynthetic cyclic electron flow in Chlamydomonas reinhardtii (I) aerobic conditions

    E-print Network

    ) aerobic conditions Jean Alric a, , Jérôme Lavergne b , Fabrice Rappaport a a UMR 7141, CNRS et Université a continuous illumination under aerobic conditions. In mutants devoid of Rubisco or ATPase, where the reducing. The present data show that the cyclic electron flow can operate under aerobic conditions and support a simple

  15. Predation Intensity Does Not Cause Microevolutionary Change in Maximum Speed or Aerobic Capacity in Trinidadian Guppies

    E-print Network

    Saltzman, Wendy

    27 Predation Intensity Does Not Cause Microevolutionary Change in Maximum Speed or Aerobic Capacity burst and aerobic performance. o2max was higher than predicted from allometry, and restingV o2 was lower-mediated evolution of guppy life history does not produce concomitant evolution in aerobic capacity and maximum burst

  16. Measurement Agreement between Estimates of Aerobic Fitness in Youth: The Impact of Body Mass Index

    ERIC Educational Resources Information Center

    Saint-Maurice, Pedro F.; Welk, Gregory J.; Laurson, Kelly R.; Brown, Dale D.

    2014-01-01

    Purpose: The purpose of this study was to examine the impact of body mass index (BMI) on the agreement between aerobic capacity estimates from different Progressive Aerobic Cardiorespiratory Endurance Run (PACER) equations and the Mile Run Test. Method: The agreement between 2 different tests of aerobic capacity was examined on a large data set…

  17. Active Site Engineering of the Epoxide Hydrolase from Agrobacterium radiobacter AD1 to Enhance Aerobic Mineralization

    E-print Network

    Wood, Thomas K.

    Aerobic Mineralization of cis-1,2-Dichloroethylene in Cells Expressing an Evolved Toluene ortho- water pollutants, and the toxic epoxides generated dur- ing their aerobic biodegradation limit and genetically adapt this universally successful detoxification strategy to the process of aerobic, cometabolic

  18. Proteome Changes after Metabolic Engineering to Enhance Aerobic Mineralization of cis-1,2-Dichloroethylene

    E-print Network

    Wood, Thomas K.

    Proteome Changes after Metabolic Engineering to Enhance Aerobic Mineralization of cis-1 dehydrogenase). Hence, the metabolic engineering that leads to enhanced aerobic degradation of 1 mM cis-DCE (2 pollutant,1 and degrading cis-DCE aerobically is important, since anaerobic degradation leads to formation

  19. p53 Improves Aerobic Exercise Capacity and Augments Skeletal Muscle Mitochondrial DNA Content

    E-print Network

    Leary, Scot

    p53 Improves Aerobic Exercise Capacity and Augments Skeletal Muscle Mitochondrial DNA Content Joon: The purpose of this study was to understand the genetic mechanism by which p53 regulates aerobic exercise / compared to p53 / mice was more marked in aerobic versus glycolytic skeletal muscle groups

  20. The medically important aerobic actinomycetes: epidemiology and microbiology.

    PubMed Central

    McNeil, M M; Brown, J M

    1994-01-01

    The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medically important aerobic actinomycetes may cause significant morbidity and mortality, in particular in highly susceptible severely immunocompromised patients, including transplant recipients and patients infected with human immunodeficiency virus. However, the diagnosis of these infections may be difficult, and effective antimicrobial therapy may be complicated by antimicrobial resistance. The taxonomy of these microorganisms has been problematic. In recent revisions of their classification, new pathogenic species have been recognized. The development of additional and more reliable diagnostic tests and of a standardized method for antimicrobial susceptibility testing and the application of molecular techniques for the diagnosis and subtyping of these microorganisms are needed to better diagnose and treat infected patients and to identify effective control measures for these unusual pathogens. We review the epidemiology and microbiology of the major medically important aerobic actinomycetes. Images PMID:7923055

  1. Aerobic Fitness for the Severely and Profoundly Mentally Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    The booklet discusses the aerobic fitness capacities of severely/profoundly retarded students and discusses approaches for improving their fitness. An initial section describes a method for determining the student's present fitness level on the basis of computations of height, weight, blood pressure, resting pulse, and Barach Index and Crampton…

  2. Group Aquatic Aerobic Exercise for Children with Disabilities

    ERIC Educational Resources Information Center

    Fragala-Pinkham, Maria; Haley, Stephen M.; O'Neill, Margaret E.

    2008-01-01

    The effectiveness and safety of a group aquatic aerobic exercise program on cardiorespiratory endurance for children with disabilities was examined using an A-B study design. Sixteen children (11 males, five females) age range 6 to 11 years (mean age 9y 7mo [SD 1y 4mo]) participated in this twice-per-week program lasting 14 weeks. The children's …

  3. AUTOTHERMAL THERMOPHILIC AEROBIC DIGESTION IN THE FEDERAL REPUBLIC OF GERMANY

    EPA Science Inventory

    The status of Autothermal Thermophilic Aerobic Digestion (ATAD) of Wastewater Sludges in the Federal Republic of Germany (FRG) was evaluated via site visits to operating facilities. In the FRG, three variations of ATAD systems have been constructed on a full scale. These include ...

  4. Aerobic Capacity in Children and Adolescents with Cerebral Palsy

    ERIC Educational Resources Information Center

    Verschuren, Olaf; Takken, Tim

    2010-01-01

    This study described the aerobic capacity [VO[subscript 2peak] (ml/kg/min)] in contemporary children and adolescents with cerebral palsy (CP) using a maximal exercise test protocol. Twenty-four children and adolescents with CP classified at Gross Motor Functional Classification Scale (GMFCS) level I or level II and 336 typically developing…

  5. Characterization of aerobic ethanol productions in a computerized auxostat

    SciTech Connect

    Fraleigh, S.P.

    1989-01-01

    For many valuable bioproducts high productivity is associated with rapid growth. However, most continuous microbial cultures become unstable when the dilution rate is fixed near the value for maximum growth rate. The auxostat culture technique employs feedback control of a nutrient or metabolite to stabilize the biomass at its maximum potential growth rate. An auxostat device is therefore ideal for study of bioprocesses involving the overproduction of primary metabolites such as ethanol. Oxidoreductive transformations involving ethanol are utilized by Saccharomyces yeasts when normal respiration cannot satisfy energy needs. When rapid growth or other stress creates oxidoreductive conditions in aerobic Saccharomyces cultures, very high specific ethanol formation rates are established and biomass yield drops to levels more typical of anaerobic fermentation. Although the physiology is favorable, the potential for large-scale aerobic ethanol processes to compete with traditional anaerobic fermentations has not previously been assessed. In this study, a fully computerized auxostat device was constructed and used to characterize the specific and volumetric aerobic ethanol productivity of the yeast Saccharomyces cerevisiae. To divert substrate away from biomass and into product formation, aerobic cultures were stressed with variations of ionic balance (via extreme K{sup +} and H{sup +} setpoints) in the auxostat device. During growth with limiting K{sup +} concentrations, the goal of very low biomass yield was attained but the rate of ethanol production was poor. However, with excess K{sup +} the volumetric productivity reached 6.1 g/I,-h, a value that is comparable to optimized, continuous anaerobic cultures.

  6. Aerobic Digestion. Biological Treatment Process Control. Instructor's Guide.

    ERIC Educational Resources Information Center

    Klopping, Paul H.

    This unit on aerobic sludge digestion covers the theory of the process, system components, factors that affect the process performance, standard operational concerns, indicators of steady-state operations, and operational problems. The instructor's guide includes: (1) an overview of the unit; (2) lesson plan; (3) lecture outline (keyed to a set of…

  7. AEROBIC BIODEGRADABILITY AND TOXICITY OF NON-PETROLEUM OILS.

    EPA Science Inventory

    Vegetable oil spills are a widely known phenomenon, but are the least understood. These spills can be as devastating to the environment as petroleum oil spills. Previous laboratory research results have indicated that as vegetable oils degrade aerobically, the aqueous solutions b...

  8. DEMONSTRATION OF THERMOPHILIC AEROBIC-ANAEROBIC DIGESTION AT HAGERSTOWN, MARYLAND

    EPA Science Inventory

    This report describes the successful operation of a new and novel approach to digestion of sludge at the Hagerstown wastewater treatment plant. The process, known as dual digestion, involved the coupling of a full-scale experimental aerobic reactor to an existing full-scale anaer...

  9. AUTOHEATED, AEROBIC, THERMOPHILIC DIGESTION OF MUNICIPAL SLUDGE WITH AIR AERATION

    EPA Science Inventory

    A full-scale aerobic digestion system demonstrated that a simple self-aspirating aerator, that used ambient air, could achieve high oxygen transfer efficiencies and thereby allow conservation of heat. Continuous feed operation utilizing primary and waste activated sludges resulte...

  10. AEROBIC BIODEGRADATION OF GASOLINE OXYGENATES MTBE AND TBA

    EPA Science Inventory

    MTBE degradation was investigated using a continuously stirred tank reactor (CSTR) with biomass retention (porous pot reactor) operated under aerobic conditions. MTBE was fed to the reactor at an influent concentration of 150 mg/l (1.70 mmol/l). A second identifical rector was op...

  11. Relative importance of aerobic versus resistance training for healthy aging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review will focus on the importance of aerobic and resistance modes of physical activity for healthy aging as supported by findings in 2007. In line with public health recommendations, several studies in 2007 employed an exercise paradigm that combined both modes of physical activity. While a...

  12. Aerobic Capacities of Early College High School Students

    ERIC Educational Resources Information Center

    Loflin, Jerry W.

    2014-01-01

    The Early College High School Initiative (ECHSI) was introduced in 2002. Since 2002, limited data, especially student physical activity data, have been published pertaining to the ECHSI. The purpose of this study was to examine the aerobic capacities of early college students and compare them to state and national averages. Early college students…

  13. COMMERCIAL-SCALE AEROBIC-ANAEROBIC BIOREACTOR LANDFILL OPERATIONS

    EPA Science Inventory

    A sequential aerobic-anaerobic treatment system has been applied at a commercial scale (3,000 ton per day) municipal solid waste landfill in Kentucky, USA since 2001. In this system, the uppermost layer of landfilled waste is aerated and liquid waste including leachate, surface w...

  14. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Aerobic aquatic biodegradation. 796... measure the amount of CO2 evolved. Differences in the extent of DOC disappearance and CO2 evolution... Erlenmeyer flask. EC01AP92.039 Figure 1—Shake-Flask System for Carbon Dioxide Evolution The Ba(OH)2...

  15. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 33 2012-07-01 2012-07-01 false Aerobic aquatic biodegradation. 796... measure the amount of CO2 evolved. Differences in the extent of DOC disappearance and CO2 evolution... Erlenmeyer flask. EC01AP92.039 Figure 1—Shake-Flask System for Carbon Dioxide Evolution The Ba(OH)2...

  16. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Aerobic aquatic biodegradation. 796... measure the amount of CO2 evolved. Differences in the extent of DOC disappearance and CO2 evolution... Erlenmeyer flask. EC01AP92.039 Figure 1—Shake-Flask System for Carbon Dioxide Evolution The Ba(OH)2...

  17. PHYLOGENETIC ANALYSIS OF A BACTERIAL AEROBIC DEGRADER OF AZO DYES

    EPA Science Inventory

    Eubacterial consensus oligonucleotide primers were used to amplify by polymerase chain reaction the nearly full-length 16S rRNA gene of isolate C7, a gram-negative rod capable of aerobic degradation of azo dyes. he DNA produce was cloned and sequenced. hylogenetic analysis based ...

  18. Teaching Aerobic Cell Respiration Using the 5Es

    ERIC Educational Resources Information Center

    Patro, Edward T.

    2008-01-01

    The 5E teaching model provides a five step method for teaching science. While the sequence of the model is strictly linear, it does provide opportunities for the teacher to "revisit" prior learning before moving on. The 5E method is described as it relates to the teaching of aerobic cell respiration.

  19. Stable Carbon Isotope Fractionation during Aerobic Biodegradation of

    E-print Network

    Chu, Kung-Hui "Bella"

    Stable Carbon Isotope Fractionation during Aerobic Biodegradation of Chlorinated Ethenes K U N G and Caldwell, 201 North Civic Drive, Walnut Creek, California 94596, and Center for Isotope Geochemistry, MS 70A-4418, Lawrence Berkeley National Laboratory, Berkeley, California 94720 Stable isotope analysis

  20. Aerobic denitrification in permeable Wadden Sea sediments.

    PubMed

    Gao, Hang; Schreiber, Frank; Collins, Gavin; Jensen, Marlene M; Svitlica, Olivera; Kostka, Joel E; Lavik, Gaute; de Beer, Dirk; Zhou, Huai-yang; Kuypers, Marcel M M

    2010-03-01

    Permeable or sandy sediments cover the majority of the seafloor on continental shelves worldwide, but little is known about their role in the coastal nitrogen cycle. We investigated the rates and controls of nitrogen loss at a sand flat (Janssand) in the central German Wadden Sea using multiple experimental approaches, including the nitrogen isotope pairing technique in intact core incubations, slurry incubations, a flow-through stirred retention reactor and microsensor measurements. Results indicate that permeable Janssand sediments are characterized by some of the highest potential denitrification rates (> or =0.19 mmol N m(-2) h(-1)) in the marine environment. Moreover, several lines of evidence showed that denitrification occurred under oxic conditions. In intact cores, microsensor measurements showed that the zones of nitrate/nitrite and O(2) consumption overlapped. In slurry incubations conducted with (15)NO(3)(-) enrichment in gas-impermeable bags, denitrification assays revealed that N(2) production occurred at initial O(2) concentrations of up to approximately 90 microM. Initial denitrification rates were not substantially affected by O(2) in surficial (0-4 cm) sediments, whereas rates increased by twofold with O(2) depletion in the at 4-6 cm depth interval. In a well mixed, flow-through stirred retention reactor (FTSRR), (29)N(2) and (30)N(2) were produced and O(2) was consumed simultaneously, as measured online using membrane inlet mass spectrometry. We hypothesize that the observed high denitrification rates in the presence of O(2) may result from the adaptation of denitrifying bacteria to recurrent tidally induced redox oscillations in permeable sediments at Janssand. PMID:20010631