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1.
Microbiol Res ; 211: 47-56, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29705205

RESUMO

A novel halotolerant species of cyanobacterium of the order Chroococcales was isolated from hypersaline estuary in Kwa-Zulu Natal, South Africa. A comprehensive polyphasic approach viz., cell morphology, pigment composition and complete genome sequence analysis was conducted to elucidate the taxonomic position of the isolated strain. The blue-green oval to rod-shaped cells were 14-18 µm in size, and contained a high amount of phycocyanin pigments. The strain was moderate thermotolerant/alkalitolerant halophile with the optimum conditions for growth at 35 °C, pH 8.5 and 120 g/l of NaCl. Based on 16S rRNA gene sequence phylogeny, the strain was related to members of the 'Euhalothece' subcluster (99%). The whole genome sequence was determined, and the annotated genes showed a 90% sequence similarity to the gas-vacuolate, spindle-shaped Dactylococcopsis salina PCC 8305. The size of the genome was determined to be 5,113,178 bp and contained 4332 protein-coding genes and 69 RNA genes with a G + C content of 46.7%. Genes encoding osmoregulation, oxidative stress, heat shock, persister cells, and UV-absorbing secondary metabolites, among others, were identified. Based on the phylogenetic analysis of the 16S rRNA gene sequences, physiological data, pigment compositions and genomic data, the strain is considered to represent a novel species of Euhalothece.


Assuntos
Cianobactérias/classificação , Cianobactérias/citologia , Cianobactérias/genética , Cianobactérias/isolamento & purificação , Genótipo , Fenótipo , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , Biomassa , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Genes Bacterianos/genética , Tamanho do Genoma , Proteínas de Choque Térmico/genética , Concentração de Íons de Hidrogênio , Osmorregulação/genética , Estresse Oxidativo/genética , Ficocianina/metabolismo , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Tolerância ao Sal , Análise de Sequência de DNA , Cloreto de Sódio/metabolismo , África do Sul , Especificidade da Espécie , Temperatura Ambiente , Sequenciamento Completo do Genoma
2.
Microb Ecol ; 67(2): 358-68, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24337806

RESUMO

The performance of a full-scale upflow anaerobic sludge blanket (UASB) reactor treating brewery wastewater was investigated by microbial analysis and kinetic modelling. The microbial community present in the granular sludge was detected using fluorescent in situ hybridization (FISH) and further confirmed using polymerase chain reaction. A group of 16S rRNA based fluorescent probes and primers targeting Archaea and Eubacteria were selected for microbial analysis. FISH results indicated the presence and dominance of a significant amount of Eubacteria and diverse group of methanogenic Archaea belonging to the order Methanococcales, Methanobacteriales, and Methanomicrobiales within in the UASB reactor. The influent brewery wastewater had a relatively high amount of volatile fatty acids chemical oxygen demand (COD), 2005 mg/l and the final COD concentration of the reactor was 457 mg/l. The biogas analysis showed 60-69% of methane, confirming the presence and activities of methanogens within the reactor. Biokinetics of the degradable organic substrate present in the brewery wastewater was further explored using Stover and Kincannon kinetic model, with the aim of predicting the final effluent quality. The maximum utilization rate constant U max and the saturation constant (K(B)) in the model were estimated as 18.51 and 13.64 g/l/day, respectively. The model showed an excellent fit between the predicted and the observed effluent COD concentrations. Applicability of this model to predict the effluent quality of the UASB reactor treating brewery wastewater was evident from the regression analysis (R(2) = 0.957) which could be used for optimizing the reactor performance.


Assuntos
Bactérias/isolamento & purificação , Reatores Biológicos/microbiologia , Euryarchaeota/isolamento & purificação , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Biocombustíveis/análise , DNA Arqueal/isolamento & purificação , DNA Bacteriano/isolamento & purificação , Ácidos Graxos Voláteis/análise , Hibridização in Situ Fluorescente , Metano/análise , Modelos Químicos , Reação em Cadeia da Polimerase
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