Supercritical Fluid Extraction of Quinones from Compost for Microbial Community Analysis

Supercritical fluid extraction (SFE) was used to extract quinones from compost to monitor the microbial community dynamics during composting. The 0.3 g of dried compost was extracted using 3 mL min−1of carbon dioxide (90%) and methanol (10%) at 45°C and 25 MPa for a 30 min extraction time. The extracted quinones were analysed using ultra performance liquid chromatography (UPLC) with 0.3 mL min−1of methanol mobile phase for a 50 min chromatographic run time. A comparable detected amount of quinones was obtained using the developed method and an organic solvent extraction method, being 36.06 μmol kg−1and 34.54 μmol kg−1, respectively. Significantly low value of dissimilarity index (D) between the two methods (0.05) indicated that the quinone profile obtained by both methods was considered identical. The developed method was then applied to determine the maturity of the compost by monitoring the change of quinone during composting. The UQ-9 and MK-7 were predominant quinones in the initial stage of composting. The diversity of quinone became more complex during the cooling and maturation stages. This study showed that SFE had successfully extracted quinones from a complex matrix with simplification and rapidity of the analysis that is beneficial for routine analysis.

Otariodibacter oris gen. nov., sp. nov., a member of the family Pasteurellaceae isolated from the oral cavity of pinnipeds

A total of 27 bacterial isolates from California sea lions and a walrus tentatively classified within the family Pasteurellaceae was further characterized by genotypic and phenotypic tests. Phylogenetic analysis of partial 16S rRNA and rpoB gene sequences showed that the isolates investigated formed a monophyletic group, tentatively designated Bisgaard taxon 57. According to 16S rRNA gene sequences, the most closely related species with a validly published name was Bisgaardia hudsonensis and the most closely related species based on rpoB sequence comparison was Pasteurella multocida subsp. multocida; highest similarities between the isolates and the type strains of B. hudsonensis and P. multocida subsp. multocida were 95.0 and 88.2%. respectively. All isolates of Bisgaard taxon 57 exhibit the phenotypic characters of the family Pasteurellaceae . Members of Bisgaard taxon 57 can be separated from existing genera of the Pasteurellaceae by the following tests: positive reactions for catalase, oxidase, Voges–Proskauer and indole; no X- or V-factor dependency; and acid production from l-arabinose (slow), l-fucose, maltose and trehalose, but not from dulcitol, d-mannitol, d-mannose or sucrose. The main fatty acids of Bisgaard taxon 57 (CCUG 59994T) are C14 : 0, C16 : 0, C16 : 1ω7c and the summed feature C14 : 0 3-OH/iso-C16 : 1 I. This fatty acid profile is characteristic of members of the Pasteurellaceae . The quinone profile of Bisgaard taxon 57 (DSM 23800T) was similar to that of other genera in the Pasteurellaceae . The DNA G+C content of strain Baika1T is 36.2 mol%, which is at the lower end of the range for members of the family Pasteurellaceae . On the basis of both phylogenetic and phenotypic evidence, it is proposed that members of Bisgaard taxon 57 should be classified as representatives of a novel species in a new genus, Otariodibacter oris gen. nov., sp. nov. The type strain of Otariodibacter oris is Baika1T ( = CCUG 59994T = DSM 23800T), which was isolated from the oral cavity of a healthy California sea lion in Copenhagen Zoo, Denmark, in 2007.

Preliminary Discussion on the Activity of Denitrifying Phosphorus-Removing Bacteria in Sequencing Batch Reactors by Quinone Profile Analysis

Based on DPBs (Denitrifying Phosphorus-removing Bacteria) obtained from a lab-scale SBR, a quinone profile system had been established to analyze quinones in sludge samples. There existed a positive correlation between the contents of UQ-8 extracted from the sludge samples and the denitrifying and phosphorus removal efficiency of the treating system. With quinone profiles taken as a new important index, it was evidently feasible to determine the removal effect.

Microbial population structure changes in a suspended carrier biofilm reactor

The changes of microbial population structure in biofilm caused by variations of COD/NHNH+4-N ratio in influent were investigated in a suspended carrier biofilm reactor (SCBR). When COD/NHNH+4-N was 10, the highest COD removal reached was about 73.8 per cent, whereas the highest NH+4-N removal, about 55.9 per cent, was reached when COD/NH+4-N was 5. By using fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) observation, it was found that the thickness of the biofilm formed on the carrier was about 80 to 120 μm, and ammonia-oxidizing bacteria (AOB) and nitrifying bacteria existed mainly in the upper layer about 20 to 30 μm. The results of the quinone profile analysis showed that when the COD/NH+4-N increased, the microbial diversity (DQ) increased, while the proportions of AOB and nitrifying bacteria in the biofilm communities decreased.

Evaluation of hydrological processes in a mountainous small basin using a quinone biomarker

An applicability of quinone biomarker to the analysis of hillslope runoff was investigated. At first, quinone profiles of three streams as well as a hillslope runoff in a forested headwater catchment were compared. The quinone composition of hillslope runoff differed from others. Moreover, there were remarkable differences in quinone profile of hillslope runoff under different rainfall conditions. Then, the behavior of quinone biomarker during the increase and decrease of hillslope runoff after a rainfall event was examined. The fractional changes in Q-9 (H2), Q-10 (H2), Q-11, MK-6 and MK-10 suggested the effect of interflow.

Menaquinone-Specific Prenyl Reductase from the Hyperthermophilic Archaeon Archaeoglobus fulgidus

ABSTRACT Four genes that encode the homologues of plant geranylgeranyl reductase were isolated from a hyperthermophilic archaeon Archaeoglobus fulgidus, which produces menaquinone with a fully saturated heptaprenyl side chain, menaquinone-7(14H). The recombinant expression of one of the homologues in Escherichia coli led to a distinct change in the quinone profile of the host cells, although the homologue is the most distantly related to the geranylgeranyl reductase. The new compounds found in the profile had successively longer elution times than those of ordinary quinones from E. coli, i.e., menaquinone-8 and ubiquinone-8, in high-performance liquid chromatography on a reversed-phase column. Structural analyses of the new compounds by electron impact-mass spectrometry indicated that their molecular masses progressively increase relative to the ordinary quinones at a rate of 2 U but that they still contain quinone head structures, strongly suggesting that the compounds are quinones with partially saturated prenyl side chains. In vitro assays with dithionite as the reducing agent showed that the prenyl reductase is highly specific for menaquinone-7, rather than ubiquinone-8 and prenyl diphosphates. This novel enzyme noncovalently binds flavin adenine dinucleotide, similar to geranylgeranyl reductase, but was not able to utilize NAD(P)H as the electron donor, unlike the plant homologue.