RESUMO
A dairy wastewater treatment system composed of the 1st segment (no aeration) equipped with a facility for the destruction of milk fat particles, four successive aerobic treatment segments with activated sludge and a final sludge settlement segment was developed. The activated sludge is circulated through the six segments by settling sediments (activated sludge) in the 6th segment and sending the sediments beck to the 1st and 2nd segments. Microbiota was examined using samples from the non-aerated 1st and aerated 2nd segments obtained from two farms using the same system in summer or winter. Principal component analysis showed that the change in microbiota from the 1st to 2nd segments concomitant with effective wastewater treatment is affected by the concentrations of activated sludge and organic matter (biological oxygen demand [BOD]), and dissolved oxygen (DO) content. Microbiota from five segments (1st and four successive aerobic segments) in one location was also examined. Although the activated sludge is circulating throughout all the segments, microbiota fluctuation was observed. The observed successive changes in microbiota reflected the changes in the concentrations of organic matter and other physicochemical conditions (such as DO), suggesting that the microbiota is flexibly changeable depending on the environmental condition in the segments. The genera Dechloromonas, Zoogloea and Leptothrix are frequently observed in this wastewater treatment system throughout the analyses of microbiota in this study.
Assuntos
Bactérias/classificação , Indústria de Laticínios , Monitoramento Ambiental , Eliminação de Resíduos Líquidos , Águas Residuárias/microbiologia , Análise da Demanda Biológica de Oxigênio , Estações do AnoRESUMO
Milk fat curdle is difficult to remove from sewage. In an attempt to identify an appropriate agent for bio-remediation of milk fat curdle, Mrakia strains were collected from the Skarvsnes ice-free area of Antarctica. A total of 27 strains were isolated and tested for their ability to decompose milk fat at temperatures ranging from 4°C to 15°C. All strains could decompose milk fat at 4°C and 10°C. Phylogenetic analysis and comparison of the decomposition ability of milk fat (DAMF) revealed that the DAMF may be useful for predicting the outcome of phylogenetic analysis based on ITS sequences.
Assuntos
Basidiomycota/metabolismo , Temperatura Baixa , Metabolismo dos Lipídeos/fisiologia , Leite/metabolismo , Animais , Regiões Antárticas , Basidiomycota/classificação , Biodegradação Ambiental , Gelo , FilogeniaRESUMO
The Antarctic basidiomycetous yeast Mrakia blollopis SK-4 can quite uniquely ferment various sugars under low temperature conditions. When strain SK-4 fermented lignocellulosic biomass using the direct ethanol fermentation (DEF) technique, approximately 30% to 65% of the theoretical ethanol yield was obtained without and with the addition of the non-ionic surfactant Tween 80, respectively. Therefore, DEF from lignocellulosic biomass with M. blollopis SK-4 requires the addition of a non-ionic surfactant to improve fermentation efficiency. DEF with lipase converted Eucalyptus and Japanese cedar to 12.6g/l, and 14.6g/l ethanol, respectively. In the presence of 1% (v/v) Tween 80 and 5U/g-dry substrate lipase, ethanol concentration increased about 1.4- to 2.4-fold compared to that without Tween 80 and lipase. We therefore consider that the combination of M. blollopis SK-4 and DEF with Tween 80 and lipase has good potential for ethanol fermentation in cold environments.
Assuntos
Basidiomycota/metabolismo , Etanol/metabolismo , Fermentação/fisiologia , Madeira/metabolismo , Regiões Antárticas , Biomassa , Temperatura BaixaRESUMO
The Antarctic basidiomycetous yeast Mrakia blollopis SK-4 fermented ethanol between pH 5.0 and pH 10.0 with optimum pH at 8.0-10.0. Knowledge of ethanol fermentability as to the genus Mrakia remains incomplete. Further experiments are required to elucidate the ethanol fermentability of genus e.g., as to optimum fermentation pH, optimum fermentation temperature, and cell viability during fermentation.
Assuntos
Basidiomycota/metabolismo , Etanol/metabolismo , Regiões Antárticas , Basidiomycota/citologia , Sobrevivência Celular , Fermentação , Concentração de Íons de HidrogênioRESUMO
Milk fat curdle in sewage is one of the refractory materials for active sludge treatment under low temperature conditions. For the purpose of solving this problem by using a bio-remediation agent, we screened Antarctic yeasts and isolated SK-4 strain from algal mat of sediments of Naga-ike, a lake in Skarvsnes, East Antarctica. The yeast strain showed high nucleotide sequence homologies (>99.6%) to Mrakia blollopis CBS8921(T) in ITS and D1/D2 sequences and had two unique characteristics when applied on an active sludge; i.e., it showed a potential to use various carbon sources and to grow under vitamin-free conditions. Indeed, it showed a biochemical oxygen demand (BOD) removal rate that was 1.25-fold higher than that of the control. We considered that the improved BOD removal rate by applying SK-4 strain was based on its lipase activity and characteristics. Finally, we purified the lipase from SK-4 and found that the enzyme was quite stable under wide ranges of temperatures and pH, even in the presence of various metal ions and organic solvents. SK-4, therefore, is a promising bio-remediation agent for cleaning up unwanted milk fat curdles from dairy milk wastewater under low temperature conditions.
Assuntos
Basidiomycota/enzimologia , Lipase/metabolismo , Águas Residuárias/microbiologia , Regiões Antárticas , Basidiomycota/isolamento & purificação , Biodegradação Ambiental , Temperatura Baixa , Eliminação de Resíduos LíquidosRESUMO
A psychrotolerant, obligately alkaliphilic bacterium, IDR2-2(T), which is able to reduce indigo dye was isolated from a fermented polygonum indigo (Polygonum tinctorium Lour.) produced in Date, Hokkaido, using a traditional Japanese method. The isolate grew at pH 9-12 but not at pH 7-8. It was a Gram-positive, facultatively anaerobic, straight rod-shaped bacterium with peritrichous flagella. The isolate grew in 0-17 % (w/v) NaCl but not at NaCl concentrations higher than 18 % (w/v). Its major cellular fatty acids were C(14 : 0), C(16 : 0), C(16 : 1)9c and C(18 : 1)9c, and its DNA G+C content was 40.6 mol%. dl-lactic acid was the major end-product from d-glucose. No quinones could be detected. The peptidoglycan type was A4beta, Orn-d-Glu. A phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain IDR2-2(T) is a member of the genus Alkalibacterium. DNA-DNA hybridization revealed low relatedness (less than 25 %) between the isolate and two phylogenetically related strains, Alkalibacterium olivapovliticus and Marinilactibacillus psychrotolerans. On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA relatedness data, the isolate merits classification as a novel species, for which the name Alkalibacterium psychrotolerans sp. nov. is proposed. The type strain is IDR2-2(T) (=JCM 12281(T)=NCIMB 13981(T)).
Assuntos
Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/isolamento & purificação , Indóis/metabolismo , Polygonum/microbiologia , Anaerobiose , Técnicas de Tipagem Bacteriana , Composição de Bases , Temperatura Baixa , DNA Bacteriano/química , DNA Bacteriano/isolamento & purificação , DNA Ribossômico/química , DNA Ribossômico/isolamento & purificação , Ácidos Graxos/análise , Ácidos Graxos/química , Ácidos Graxos/isolamento & purificação , Fermentação , Flagelos , Genes de RNAr , Violeta Genciana , Glucose/metabolismo , Bactérias Gram-Positivas/citologia , Bactérias Gram-Positivas/metabolismo , Concentração de Íons de Hidrogênio , Índigo Carmim , Japão , Ácido Láctico/metabolismo , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Oxirredução , Peptidoglicano/química , Peptidoglicano/isolamento & purificação , Fenazinas , Filogenia , Quinonas/análise , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Solução Salina Hipertônica , Análise de Sequência de DNARESUMO
A facultatively psychrophilic bacterium, strain MD17(T), which hydrolyses lipids at 5 degrees C, was isolated from the Monbetsu coast of the Okhotsk Sea in Hokkaido, Japan, when ice carried by the cold current came to the area. The isolate is an aerobic, non-motile coccobacillus that reduces nitrate to nitrite and hydrolyses Tweens 20, 40, 60 and 80, but not gelatin, DNA or alginic acid. The isolate grows at 0 degrees C, but not at temperatures higher than 36 degrees C; its optimum growth temperature is 25 degrees C. It grows in the presence of 0-10 % NaCl. Its major isoprenoid quinone is ubiquinone-8 (Q-8) and its DNA G+C content is 46.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MD17(T) is closely related to Psychrobacter glacincola DSM 12194(T) (99.0 % similarity) and Psychrobacter immobilis DSM 7229(T) (98.7 % similarity). DNA-DNA hybridization revealed 45.9 % relatedness between strain MD17(T) and P. immobilis ATCC 43116(T) and 33.4 % between strain MD17(T) and P. glacincola ATCC 700754(T). Based on physiological and biochemical characteristics, phylogenetic position (as determined by 16S rRNA gene sequence analysis) and DNA-DNA relatedness, it is concluded that the isolate should be designated as a novel species, for which the name Psychrobacter okhotskensis sp. nov. is proposed. The type strain is MD17(T) (=NCIMB 13931(T)=JCM 11840(T)).
Assuntos
Moraxellaceae/classificação , Filogenia , Composição de Bases , Sequência de Bases , DNA Bacteriano/química , Japão , Dados de Sequência Molecular , Moraxellaceae/enzimologia , Moraxellaceae/genética , Moraxellaceae/isolamento & purificação , Água do Mar/microbiologia , TemperaturaRESUMO
A novel moderately thermophilic bacterium, strain TH13T, was isolated from a hot spring in Kamchatka. It was found to be a Gram-positive, facultative aerobe; the straight, non-motile rods grew at 30-64 degrees C (optimum 54 degrees C). The isolate was positive for catalase and oxidase tests and reduced nitrate to nitrite, but was negative for H2S production and growth in more than 3% NaCl (w/v). The isolate grew at pH 7-8, but not at pH values higher than 9. The DNA G+C content was 43.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain TH13T was a member of the genus Anoxybacillus. DNA-DNA hybridization revealed a low relatedness (less than 30.2%) between the isolate and its close phylogenetic neighbours Anoxybacillus pushchinoensis and Anoxybacillus flavithermus. On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA hybridization data, it was concluded that the isolate merited classification as a novel species, for which the name Anoxybacillus voinovskiensis sp. nov. is proposed. The type strain of this species is TH13T (=NCIMB 13956T=JCM 12111T).