RESUMO
Three aniline-degrading bacteria, strains DN316(T), DN316-1 and DN365, were isolated from activated sludge. According to 16S rRNA gene sequence-based phylogenetic analysis, the isolates belonged to the genus Rhizobium, with Rhizobium (â=âAgrobacterium) radiobacter LMG 140(T) as the closest relative, with 96.5â% sequence similarity. Phylogenetic analysis of the representative strain DN316(T) using sequences of the glnA, thrC and recA genes and the 16S-23S intergenic spacer region confirmed the phylogenetic arrangement obtained from analysis of the 16S rRNA gene. DNA-DNA relatedness between DN316(T) and R. radiobacter LMG 140(T) was 43.7â%, clearly indicating that the representative strain DN316(T) represents a novel species. Phenotypic and biochemical characterization of the isolates and insertion sequence-PCR fingerprinting patterns showed several distinctive features that differentiated them from closely related species. The major components of the cellular fatty acids were C(18â:â1)ω7c (57.10â%), C(16â:â0) (11.31â%) and C(19â:â0) cyclo ω8c (10.13â%). Based on our taxonomic analysis, the three isolates from activated sludge represent a novel species of the genus Rhizobium, for which the name Rhizobium borbori sp. nov. is proposed. The type strain is DN316(T) (â=âCICC 10378(T) â=âLMG 23925(T)).
Assuntos
Compostos de Anilina/metabolismo , Rhizobium/classificação , Rhizobium/metabolismo , Esgotos/microbiologia , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , Impressões Digitais de DNA , Elementos de DNA Transponíveis , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Ácidos Graxos/análise , Genótipo , Glutamato-Amônia Ligase , Dados de Sequência Molecular , Tipagem Molecular , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S/genética , Recombinases Rec A , Rhizobium/genética , Rhizobium/isolamento & purificação , Análise de Sequência de DNARESUMO
Changes of sludge characters in a sulfate-reducing UASB reactor during the 243 day of domestication process were tracking comparison. Results showed the average diameter of granular sludge in initial domestication stages decreased to 0.99 mm compared with 1.82 mm of incubating sludge, but which was found to be increasing along with the enhance of the loading rate of reactor, the shorten of HRT, and the acceleration of hydraulic up-flow velocity. N2 stripping was used to remove H2S produced in the reactor, and the average diameter of granular sludge increased to 1.51 mm quickly when N2 stripping with the flux of 60 mL x min(-1) was used, but it decreased when the flux of N2 improved to 100 mL x min(-1). Differences in average diameter among granular sludges in different height of the reactor became unconspicuous through continuous stripping. Changes in the MLVSS and the ratio of (MLVSS/MLSS) displayed similar trends, for which firstly decreased in the earlier period then increased to 33.59 g x L(-1) and went up to 49.72 g x L(-1) steadily in the later stage, and then raised from 0.36 to 0.50 subsequently. Sulfate reduction efficiency improved from 30% to 95%, which was strongly correlated with the MLVSS (r = 0.918, p = 0.003). Scanning electron microscope analysis showed inoculating sludge was coarse and incompact, and with the dominant species of filamentous bacteria, bacillus, cocci, but granular sludge with dense microorganism community structure were observed, and in which vibrio and bacillus were the dominant species.
