RESUMO
Biodesulfurization is emerging as a valuable technology for the desulfurization of dibenzothiophene (DBT) and its alkylated substitutes, which are otherwise regarded as refractory to other physical and chemical desulfurizing techniques. The inability of the currently identified pure cultures and artificial microbial consortia due to lower desulfurization rate and product inhibition issues has compelled the researcher to look for an alternative solution. Thus, in the present study, an indigenously isolated microbial consortium was employed to tackle the desulfurization issue. Herein, we isolated several kinds of DBT desulfurizing natural microbial consortia from hydrocarbon-contaminated soil samples by conventional enrichment technique. The most effective desulfurizing microbial consortium was sequenced through illumine sequencing technique. Finally, the effect of the products of the desulfurizing pathway (such as 2-hydroxybiphenyl (2-HBP) and sulfate (SO4-2) was evaluated on the growth and desulfurization capability of the isolated consortium. The outcomes of Gibb's assay analysis showed that six isolates followed the "4S" pathway and converted DBT to 2-HBP. Among the isolates, I5 showed maximum growth rate (1.078 g/L dry cell weight) and desulfurization activity (about 77% as indicated by HPLC analysis) and was considered for further in-depth experimentation. The analysis of 16S rRNA by high-throughput sequencing approach of the I5 isolate revealed five types of bacterial phyla including Proteobacteria, Bacteroidetes, Firmicutes, Patescibacteria, and Actinobacteria (in order of abundance). The isolate showed significant tolerance to the inhibitory effect of both 2-HBP and SO4-2 and maintained growth in the presence of even about 1.0 mM initial concentration of both products. This clearly suggests that the isolate can be an efficient candidate for future in-depth desulfurization studies of coal and other fossil fuels.
Assuntos
Bactérias , Tiofenos , RNA Ribossômico 16S/genética , Tiofenos/metabolismo , Bactérias/genéticaRESUMO
AIMS: Through biodesulphurization (BDS) is possible to remove the sulphur present in fossil fuels to carry out the very strict legislation. However, this biological process is limited by the cost of the culture medium, and thus, it is important to explore cheaper alternative carbon sources, such as Jerusalem artichoke (JA). These carbon sources usually contain sulphates which interfere with the BDS process. The goal of this work was to remove the sulphates from Jerusalem artichoke juice (JAJ) through BaCl2 precipitation viewing the optimization of dibenzothiophene (DBT) desulphurization by Gordonia alkanivorans strain 1B. METHODS AND RESULTS: Using a statistical design (Doehlert distribution), the effect of BaCl2 concentration (0.125-0.625%) and pH (5-9) was studied on sulphate concentration in hydrolysed JAJ. A validated surface response derived from data indicated that zero sulphates can be achieved with 0.5-0.55% (w/v) BaCl2 at pH 7; however, parallel BDS assays showed that the highest desulphurization was obtained with the juice treated with 0.5% (w/v) BaCl2 at pH 8.73. Further assays demonstrated that enhanced DBT desulphurization was achieved using hydrolysed JAJ treated in these optimal conditions. A total conversion of 400 µmol l(-1) DBT into 2-hydroxybiphenyl (2-HBP) in <90 h was observed, attaining a 2-HBP maximum production rate of 28.2 µmol l(-1) h(-1) and a specific production rate of 5.06 µmol(-1) g(-1) (DCW) h(-1) . CONCLUSIONS: These results highlight the efficacy of the treatment applied to JAJ in making this agromaterial a promising low-cost renewable feedstock for improved BDS by the fructophilic strain 1B. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is a fundamental step viewing BDS application at the industrial level as it accounts a cost-effective production of the biocatalysts, one of the main drawbacks for BDS scale-up.
Assuntos
Combustíveis Fósseis , Frutose/metabolismo , Bactéria Gordonia/metabolismo , Helianthus/química , Enxofre/metabolismo , Carbono/metabolismo , Tiofenos/metabolismoRESUMO
BACKGROUND: The CYP2C19 genotype is a predictor of adverse cardiovascular events in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) treated with clopidogrel. OBJECTIVES: We aimed to evaluate the cost-effectiveness of a CYP2C19*2 genotype-guided strategy of antiplatelet therapy in ACS patients undergoing PCI, compared with two 'no testing' strategies (empiric clopidogrel or prasugrel). METHODS: We developed a Markov model to compare three strategies. The model captured adverse cardiovascular events and antiplatelet-related complications. Costs were expressed in 2010 US dollars and estimated using diagnosis-related group codes and Medicare reimbursement rates. The net wholesale price for prasugrel was estimated as $5.45 per day. A generic estimate for clopidogrel of $1.00 per day was used and genetic testing was assumed to cost $500. RESULTS: Base case analyses demonstrated little difference between treatment strategies. The genetic testing-guided strategy yielded the most QALYs and was the least costly. Over 15 months, total costs were $18 lower with a gain of 0.004 QALY in the genotype-guided strategy compared with empiric clopidogrel, and $899 lower with a gain of 0.0005 QALY compared with empiric prasugrel. The strongest predictor of the preferred strategy was the relative risk of thrombotic events in carriers compared with wild-type individuals treated with clopidogrel. Above a 47% increased risk, a genotype-guided strategy was the dominant strategy. Above a clopidogrel cost of $3.96 per day, genetic testing was no longer dominant but remained cost-effective. CONCLUSIONS: Among ACS patients undergoing PCI, a genotype-guided strategy yields similar outcomes to empiric approaches to treatment, but is marginally less costly and more effective.
Assuntos
Síndrome Coronariana Aguda/economia , Síndrome Coronariana Aguda/terapia , Hidrocarboneto de Aril Hidroxilases/genética , Testes Genéticos/economia , Custos de Cuidados de Saúde , Intervenção Coronária Percutânea/economia , Síndrome Coronariana Aguda/diagnóstico , Síndrome Coronariana Aguda/genética , Síndrome Coronariana Aguda/mortalidade , Hidrocarboneto de Aril Hidroxilases/metabolismo , Transtornos Cerebrovasculares/etiologia , Clopidogrel , Simulação por Computador , Análise Custo-Benefício , Citocromo P-450 CYP2C19 , Técnicas de Apoio para a Decisão , Intervalo Livre de Doença , Custos de Medicamentos , Frequência do Gene , Predisposição Genética para Doença , Hemorragia/etiologia , Humanos , Reembolso de Seguro de Saúde/economia , Estimativa de Kaplan-Meier , Cadeias de Markov , Medicare/economia , Modelos Econômicos , Infarto do Miocárdio/etiologia , Intervenção Coronária Percutânea/efeitos adversos , Intervenção Coronária Percutânea/mortalidade , Farmacogenética/economia , Fenótipo , Piperazinas/economia , Piperazinas/metabolismo , Piperazinas/uso terapêutico , Inibidores da Agregação Plaquetária/economia , Inibidores da Agregação Plaquetária/metabolismo , Inibidores da Agregação Plaquetária/uso terapêutico , Cloridrato de Prasugrel , Valor Preditivo dos Testes , Anos de Vida Ajustados por Qualidade de Vida , Medição de Risco , Fatores de Risco , Tiofenos/economia , Tiofenos/metabolismo , Tiofenos/uso terapêutico , Trombose/economia , Trombose/genética , Trombose/prevenção & controle , Ticlopidina/análogos & derivados , Ticlopidina/economia , Ticlopidina/metabolismo , Ticlopidina/uso terapêutico , Fatores de Tempo , Resultado do Tratamento , Estados UnidosRESUMO
Prasugrel is a third-generation thienopyridine which selectively inhibits the platelet P2Y(12) receptor more rapidly, more potently, and with less interindividual response variability compared with the second-generation thienopyridine clopidogrel. Large-scale phase III clinical testing showed that in high-to moderate-risk acute coronary syndrome patients undergoing percutaneous coronary intervention, prasugrel translates into a greater reduction in ischemic events, including stent thrombosis, in the short and long term compared to clopidogrel. Prasugrel, however, is associated with an increased risk of major bleeding, which is more pronounced in certain patient subgroups. The ideal patient population for prasugrel use are those patients without prior transient ischemic attack/stroke, <75 years of age and >60 kg in whom the greatest ischemic benefit is achieved without a significant increase in major bleeding risk. Dose modifications in specific populations or at given time-points may represent an avenue to minimize bleeding risk and therefore maximize the clinical benefit of prasugrel. Ongoing clinical studies with prasugrel will better define the safety and efficacy profiles of this agent and potentially set the basis for new indications for use.