Quadricoccus australiensis gen. nov., sp. nov., a β-proteobacterium from activated sludge biomass

A gram-negative coccus, designated strain Ben 117T, was obtained in axenic culture by micromanipulation from an Australian activated sludge biomass sample, which had been subjected to chlorination in order to alleviate problems associated with foaming and bulking. This isolate was a strict aerobe and grew in axenic culture, also appearing in biomass samples as cocci or clusters of cocci in tetrads, thus resembling the morphotype 'G-bacteria' seen commonly in activated sludge samples. Strain Ben 117T was non-motile, aerobic, oxidase-negative and catalase-positive and grew between 15 and 30 degrees C, with an optimum of 25-30 degrees C. The pH range for growth was between 6.0 and 8.5, with an optimum of 7.5-8.5. The isolate stained positively for intracellular polyphosphate and poly-beta-hydroxybutyrate and its G+C content was 67 mol%. 16S rDNA sequence analysis suggests that strain Ben 117T is phylogenetically different from members of the genera Amaricoccus, gram-negative 'G-bacteria' isolated previously in this laboratory. Ben 117T is a member of the Rhodocyclus group in the beta-Proteobacteria and equidistantly placed (similarity value of 95%) between Ferribacterium limneticum and Dechloromonas agitata (mean similarity value of 92% with the genus Rhodocyclus). Based on phenotypic and phylogenetic evidence, it is proposed that strain Ben 117T be designated a novel species in a new genus, Quadricoccus australiensis gen. nov., sp. nov.; the type strain is Ben 117T (= NCIMB 13738T = CIP 107055T)

A fluorescently-labelled r-RNA targeted oligonucleotide probe for the in situ detection of G-bacteria of the genus Amaricoccus in activated sludge

A fluorescently-labelled r-RNAtargeted oligonucleotide probe specific for members of the genus Amaricoccus, which includes one group of the Gram-negative G-Bacteria seen in activated sludge systems, is described. These organisms, previously ‘identified’ on their distinctive morphology of cocci in tetrads, have been associated with poor performance of biological nutrient removal (EBNR) plants, by out-competing the polyphosphate accumulating bacteria. Methods of sample preparation for probing activated sludge are detailed, and preliminary surveys of 46 plants, using this probe, show that G-Bacteria belonging to the genus Amaricoccus are seen not only in large numbers in EBNR systems but also in conventional plants. The presence of single cells of this organism was common, emphasizing the dangers of relying on morphology and cell arrangement to identify these bacteria

Biochemistry and molecular biology of exocellular fungal β-(1,3)- and β-(1,6)-glucanases

Many fungi produce exocellular β-glucan-degrading enzymes, the β-glucanases including the noncellulolytic β-(1,3)- and β-(1,6)-glucanases, degrading β-(1,3)- and β-(1,6)-glucans. An ability to purify several exocellular β-glucanases attacking the same linkage type from a single fungus is common, although unlike the β-1,3-glucanases, production of multiple β-1,6-glucanases is quite rare in fungi. Reasons for this multiplicity remain unclear and the multiple forms may not be genetically different but arise by posttranslational glycosylation or proteolytic degradation of the single enzyme. How their synthesis is regulated, and whether each form is regulated differentially also needs clarifying. Their industrial potential will only be realized when the genes encoding them are cloned and expressed in large quantities. This review considers what is known in molecular terms about their multiplicity of occurrence, regulation of synthesis and phylogenetic diversity. It discusses how this information assists in understanding their functions in the fungi producing them. It deals largely with exocellular β-glucanases which here refers to those recoverable after the cells are removed, since those associated with fungal cell walls have been reviewed recently by Adams (2004) . It also updates the earlier review by Pitson et al. (1993)

In situ identification and characterization of the microbial community structure of full-scale enhanced biological phosphorous removal plants in Japan

10.1016/j.watres.2005.05.015Water Research39132901-2914WATR

Phylogeny of the filamentous bacterium 'Nostocoida limicola' III from activated sludge

Five strains of the filamentous bacterium 'Nostocoida limicola' III were successfully isolated into pure culture from samples of activated sludge biomass from five plants in Australia. 16S rRNA gene sequence analyses showed that all isolates were members of the Planctomycetales, most closely related to Isosphaera pallida, but they differed phenotypically from this species in that they did not glide and were not thermotolerant. The ultrastructure of these 'N. limicola' III isolates was also consistent with them being Planctomycetales, in that they possessed complex intracellular membrane systems compartmentalizing the cells. However, the arrangements of these intracellular membranes differed between isolates. These data confirm that 'N. limicola' III is phylogenetically unrelated to both 'N. limicola' I and 'N. limicola' II, activated sludge filamentous bacteria which share morphological features in common with 'N. limicola' III and which have been presumed historically to be the same or very similar bacteria

Frontiers of environmental science & engineering in China : selected publications from Chinese universities

Bulking sludges were investigated in seven industrial or municipal activated sludge treatment plants from Denmark, Germany and Australia. The dominating filaments were all identified as type 021N according to the Eikelboom key. The extent of variability in the filament taxonomy was assessed using fluorescence in situ hybridization (FISH) with rRNA-targeted nucleic acid probes specific for type 021N, Thiothrix and Leucothrix. Not all of the filaments morphologically identified as type 021N hybridized with the 021N probe. In one treatment plant the predominant filament hybridized with the probe for Thiothrix and in one treatment plant the predominant filament did not hybridize with any of these probes. In none of the plants did filaments hybridize with the probe for Leucothrix. A study of the in situ uptake of different organic substrates by the various filaments was also conducted using microautogradiography. The uptake of 6 different organic substrates under aerobic conditions was studied by providing C-14 or H-3 labeled substrates (acetate, glucose, ethanol, glycine, leucine and oleic acid) in incubations of a period of 3 hours. No filaments took up all the tested substrates, and type 021N from the various treatment plants varied in their uptake abilities. The study demonstrated that strain differences with regard to substrate utilization are likely to occur among bacteria within the same genera and designated types which are indistinguishable on the basis of morphological observations alone and by the molecular probes used in this study for identification. Whether there is a clear correlation between type of wastewater and the capability of taking up the various organic substrates for the filaments remains to be elucidated

Three isolates of novel polyphosphate-accumulating gram-positive cocci, obtained from activated sludge, belong to a new genus, Tetrasphaera gen. nov., and description of two new species, Tetrasphaera japonica sp. nov. and Tetrasphaera australiensis sp. nov

Two isolates of Gram-positive cocci (Ben 109T and Ben 110) which could accumulate polyphosphate and were microscopically similar in appearance to so-called 'G-bacteria', appearing as tetrads, were isolated from samples of activated sludge biomass by micromanipulation and grown in axenic culture. On the basis of their phenotypic and chemotaxonomic characters and 16S rDNA sequences, these isolates, together with strain T1-X7T isolated and described previously in Japan, belong to a new genus. These isolates are phylogenetically different from Tessaracoccus bendigoensis, Friedmanniella spumicola and Friedmanniella capsulata, Gram-positive cocci isolated previously in this laboratory. They are characterized by type A1 gamma peptidoglycan, with meso-diaminopimelic acid as the diagnostic diamino acid. The main cellular fatty acid of Ben 109T, Ben 110 and T1-X7T is 14-methylpentadecanoic acid (i-C16:0). The major menaquinones of Ben 109T are MK-8(H4), with MK-8(H2) and MK-8 in trace amounts. In Ben 110 MK-8(H4) and MK-6(H4) are the major menaquinones, while T1-X7T has MK-8(H4), MK-7(H4) and MK-6(H4) as its menaquinones. All three contain phosphatidylinositol, phosphatidylglycerol and diphosphatidylglycerol as their polar lipids. These properties, together with 16S rDNA sequence data, suggest that they all belong to a single new genus for which the name Tetrasphaera gen. nov. is proposed. However, the lipid, cellular fatty acid profiles and DNA-DNA similarity data suggest that Ben 109T and Ben 110 are sufficiently different from T1-X7T to represent a different species of the genus Tetrasphaera. Strain T1-X7T represents the type species Tetrasphaera japonica sp. nov. of this new genus, and strains Ben 109T and Ben 110 belong to the other species, Tetrasphaera australiensis sp. nov

Ecology of the microbial community removing phosphate from wastewater under continuously aerobic conditions in a sequencing batch reactor

All activated sludge systems for removing phosphate microbiologically are configured so the biomass is cycled continuously through alternating anaerobic and aerobic zones. This paper describes a novel aerobic process capable of decreasing the amount of phosphate from 10 to 12 mg P liter−1 to less than 0.1 mg P liter−1 (when expressed as phosphorus) over an extended period from two wastewaters with low chemical oxygen demand. One wastewater was synthetic, and the other was a clarified effluent from a conventional activated sludge system. Unlike anaerobic/aerobic enhanced biological phosphate removal (EBPR) processes where the organic substrates and the phosphate are supplied simultaneously to the biomass under anaerobic conditions, in this aerobic process, the addition of acetate, which begins the feed stage, is temporally separated from the addition of phosphate, which begins the famine stage. Conditions for establishing this process in a sequencing batch reactor are detailed, together with a description of the changes in poly-β-hydroxyalkanoate (PHA) and poly(P) levels in the biomass occurring under the feed and famine regimes, which closely resemble those reported in anaerobic/aerobic EBPR processes. Profiles obtained with denaturing gradient gel electrophoresis were very similar for communities fed both wastewaters, and once established, these communities remained stable over prolonged periods of time. 16S rRNA-based clone libraries generated from the two communities were also very similar. Fluorescence in situ hybridization (FISH)/microautoradiography and histochemical staining revealed that “Candidatus Accumulibacter phosphatis” bacteria were the dominant poly(P)-accumulating organisms (PAO) in both communities, with the phenotype expected for PAO. FISH also identified large numbers of betaproteobacterial Dechloromonas and alphaproteobacterial tetrad-forming organisms related to Defluviicoccus in both communities, but while these organisms assimilated acetate and contained intracellular PHA during the feed stages, they never accumulated poly(P) during the cycles, consistent with the phenotype of glycogen-accumulating organisms