RESUMO
Many specialized technologies are available to convert waste biomass into secondary products that have a higher value and are more convenient to process than the original feedstock. This study evaluated the potential of waste pequi seeds to produce high-quality charcoal for subsequent gasification into low-tar producer gas for heat engine applications. We focused on the characterization of pequi seeds, the derived charcoal, and the collected bio-oil from slow pyrolysis conversion of the feedstock. Thermodynamic equilibrium calculations were conducted to assess gasification performance of the parent biomass and its charcoal. We also investigated the thermal degradation kinetics of pequi seeds through non-isothermal thermogravimetric analysis. Finally, a two-step energy-extraction analysis was performed for the carbonization of the parent biomass and further utilization of its charcoal in an integrated gasification gas-engine cycle. Slow pyrolysis of pequi seeds (2 °C min-1, 430 °C) produced up to 40% of high-grade charcoal with 60% fixed carbon, 43% of bio-oil, and 16% of light gases. The overall energy extraction efficiency was estimated as 61%, based on the higher heating value of wet pequi seeds. The investigation confirmed that waste pequi seeds could be considered a promising renewable energy source for combined heat and power generation for the Brazilian agro-food industry.
Assuntos
Carvão Vegetal , Temperatura Alta , Biomassa , Brasil , GasesRESUMO
BACKGROUND: Neuroblastoma is the main solid extracranial tumor of childhood. The amplification of N-myc oncogene (MYCN) and 1p deletion are the main molecular alterations. These features are what make treatment impossible, especially in high-risk patients with metastases. MATERIALS AND METHODS: Our study investigated the processes undergone by CHP-212 neuroblastoma cells, after being treated with Casiopeínas® (Cas) IIgly, IIIEa, and IIIia for 2, 10, and 24 h. RESULTS: At 2 h, all the treatments Ied to apoptosis [defined by the presence of B-cell lymphoma 2 (BCL2), BCL2-associated X protein, cytochrome c, and caspase-3]. In addition, autophagy with specific molecules beclin-1 and microtubule-associated protein 1A/1B-light chain 3 (LC3)-II/LC3-I (ratio >1). Later at 10 h, autophagy-associated proteins were observed, and at 24 h, only survival proteins nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB), and extracellular signal-regulated kinases (ERK)2/ERK1>1 were found. Another relevant finding was the presence of caspase-10 throughout the study, especially in cells treated with CasIIgly and CasIIIEa. CONCLUSION: These relationships indicate a possible mechanism of action of Casiopeínas on neuroblastoma.
Assuntos
Complexos de Coordenação/farmacologia , Neuroblastoma/metabolismo , Fenantrolinas/farmacologia , Autofagia/efeitos dos fármacos , Proteína Beclina-1/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Citocromos c/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Proteínas Associadas aos Microtúbulos/metabolismo , Neuroblastoma/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
A major pathway for the detoxification of organic hydroperoxides, such as cumene hydroperoxide (CHP), involves the MarR family transcriptional regulator OhrR and the peroxidase OhrA. However, the effect of these peroxides on the global transcriptome and the contribution of the OhrA/OhrR system to bacterial virulence remain poorly explored. Here, we analyzed the transcriptome profiles of Chromobacterium violaceum exposed to CHP and after the deletion of ohrR, and we show that OhrR controls the virulence of this human opportunistic pathogen. DNA microarray and Northern blot analyses of CHP-treated cells revealed the upregulation of genes related to the detoxification of peroxides (antioxidant enzymes and thiol-reducing systems), the degradation of the aromatic moiety of CHP (oxygenases), and protection against other secondary stresses (DNA repair, heat shock, iron limitation, and nitrogen starvation responses). Furthermore, we identified two upregulated genes (ohrA and a putative diguanylate cyclase with a GGDEF domain for cyclic di-GMP [c-di-GMP] synthesis) and three downregulated genes (hemolysin, chitinase, and collagenase) in the ohrR mutant by transcriptome analysis. Importantly, we show that OhrR directly repressed the expression of the putative diguanylate cyclase. Using a mouse infection model, we demonstrate that the ohrR mutant was attenuated for virulence and showed a decreased bacterial burden in the liver. Moreover, an ohrR-diguanylate cyclase double mutant displayed the same virulence as the wild-type strain. In conclusion, we have defined the transcriptional response to CHP, identified potential virulence factors such as diguanylate cyclase as members of the OhrR regulon, and shown that C. violaceum uses the transcriptional regulator OhrR to modulate its virulence.
Assuntos
Proteínas de Bactérias/metabolismo , Derivados de Benzeno/metabolismo , Derivados de Benzeno/farmacologia , Chromobacterium/genética , Chromobacterium/patogenicidade , Proteínas Repressoras/metabolismo , Transcrição Gênica , Animais , Carga Bacteriana , Proteínas de Bactérias/genética , Quitinases/genética , Colagenases/genética , Proteínas de Escherichia coli/genética , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Infecções por Bactérias Gram-Negativas/microbiologia , Proteínas Hemolisinas , Humanos , Peróxido de Hidrogênio , Fígado/microbiologia , Camundongos , Oxigenases/metabolismo , Peroxidases/metabolismo , Fósforo-Oxigênio Liases/genética , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Estresse Fisiológico , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Virulência , Fatores de Virulência/genéticaRESUMO
In Argentina, there is an important potential to utilize organic waste to generate bioenergy. This work analyzes the environmental impacts and the energetic and economic requirements of the biogas produced by digesting the sewage sludge (SS) produced in a wastewater treatment plant in a medium city in Argentina. The SS is co-digested with the organic fraction of municipal solid waste (OFMSW), and the basis of this study is the life cycle assessment (LCA). The LCA is performed according to ISO 14040-44 using the SimaPro simulator. First, the transport of the raw materials to the biogas plant was defined. Then, the co-digestion and the biogas treatment for final use were evaluated. The co-digestion was improved with glycerol, and the generation of biogas was estimated using the GPS-X software. Two alternatives for the end use of biogas were considered: combined heat and power (CHP) and biomethane generation. For the first, H2S and water vapor were removed from the raw biogas stream, and for the second, also CO2 was removed. The H2S removal process was simulated in the SuperPro software by anaerobic biofiltration. The same software was used to simulate the removal of CO2 absorption-desorption with water as solvent. Finally, the environmental impacts related to the end use of biogas (CHP and biomethane) were evaluated. The environmental, energetic and economic analyses showed that the co-digestion of SS and OFMSW has great potential for reducing the environmental impacts and increasing the economic and energetic value of the substances via the production of biomethane, electricity and, potentially, fertilizer.
Assuntos
Biocombustíveis , Eliminação de Resíduos/métodos , Eliminação de Resíduos Líquidos/métodos , Argentina , Custos e Análise de Custo , Fertilizantes , Incineração , Metano/biossíntese , Eliminação de Resíduos/economia , Esgotos , Resíduos Sólidos , Eliminação de Resíduos Líquidos/economiaRESUMO
Renewable substitutes for natural gas, such as biogas, require adequate treatment to remove impurities. This paper presents the life cycle and environmental impact of upgrading biogas using absorption-desorption process with three different solvents: water, diglycolamine and polyethylene glycol dimethyl ether. The results showed that water produces a minor impact in most of the considered categories, and an economic analysis showed that water is the most feasible solvent for obtaining the lowest payback period. This analysis includes three different sources for biogas production and two end uses for biomethane. The use of different wastes as sources results in different environmental impacts depending on the type of energy used in the anaerobic digestion. The same situation occurs when considering the use of biomethane as a domestic fuel or for power generation. Using energy from biogas to replace conventional energy sources in production and upgrading biogas significantly reduce the environmental impacts of processes.