Publicação
Production of biohydrogen from dark fermentation of organic wastes
| Resumo: | Nowadays hydrogen is a promising alternative to fossil fuels mainly due to its high conversion, recyclability and nonpolluting nature. Several researchers study other sources of fuel, including the use of hydrogen as energy source. The utilization of biological process, such as Dark fermentation is one of the possibilities for the hydrogen production. This process is considered one of the most promising, sustainable and environmentally friendly. Currently, energy storage has become an extremely important issue. So the search for new hydrogen-storage methods has become an important aspect in hydrogen energy applications. Zeolites is one of the most promising material for hydrogen storage. Preliminary studies using zeolites for biohydrogen dark fermentation in batch mode, revealed an improvement on the biohydrogen production. Three different ratios zeolites/biomass, 0.26, 0.13 and 0.065 g g-1 (VS), were tested. The batch assays were performed with two different medium (complex and a simple medium) and with arabinose and glucose as substrate. In both cases the increase on cumulative hydrogen production in the presence of 0.26 g zeolite g-1 (VS) biomass was significantly higher than the obtained for the control (without zeolites). A maximum hydrogen production of 1.27 mmol and 0.87 mmol was achieved for the fermentation with a complex and simple medium, respectively. Lactate, acetate and formic acid were the only soluble fermentation products (SFP) formed during dark fermentation process. The improvement of hydrogen production by zeolites was also observed in batch mode with the marine biomass, Sargassum sp., as substrate. In this case a maximum hydrogen production of 0.62 mmol was achieved in the presence of 0.13 g zeolite g-1 (VS) biomass. Due the use of a complex substrate many soluble fermentation products were formed during Sargassum sp. dark fermentation. However acetate and lactate were the most prevalent of SFP. The effect of zeolites in continuous mode, performed with glucose and arabinose as substrate (RA + G) and with only glucose (RG), was also studied. The presence of zeolites (0.26 g zeolite g-1 (VS) biomass) improve the hydrogen production rate in the two operations, reaching a maximum of 430 mL H2 L-1 d-1 and 250 mL H2 L-1 d-1, respectively. The largest amount of soluble microbial products produced for the two operations was for lactic acid. The acetate, formic acid, propionic acid and n-butyric acid formation was also observed. |
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| Autores principais: | Silva, Ana Rita Marques da |
| Assunto: | Biohydrogen Zeolites Bioreactor Sargassum sp. Dark fermentation Biohidrogénio Zeólitos Bioreator Engenharia e Tecnologia::Biotecnologia Industrial |
| Ano: | 2015 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Nowadays hydrogen is a promising alternative to fossil fuels mainly due to its high conversion, recyclability and nonpolluting nature. Several researchers study other sources of fuel, including the use of hydrogen as energy source. The utilization of biological process, such as Dark fermentation is one of the possibilities for the hydrogen production. This process is considered one of the most promising, sustainable and environmentally friendly. Currently, energy storage has become an extremely important issue. So the search for new hydrogen-storage methods has become an important aspect in hydrogen energy applications. Zeolites is one of the most promising material for hydrogen storage. Preliminary studies using zeolites for biohydrogen dark fermentation in batch mode, revealed an improvement on the biohydrogen production. Three different ratios zeolites/biomass, 0.26, 0.13 and 0.065 g g-1 (VS), were tested. The batch assays were performed with two different medium (complex and a simple medium) and with arabinose and glucose as substrate. In both cases the increase on cumulative hydrogen production in the presence of 0.26 g zeolite g-1 (VS) biomass was significantly higher than the obtained for the control (without zeolites). A maximum hydrogen production of 1.27 mmol and 0.87 mmol was achieved for the fermentation with a complex and simple medium, respectively. Lactate, acetate and formic acid were the only soluble fermentation products (SFP) formed during dark fermentation process. The improvement of hydrogen production by zeolites was also observed in batch mode with the marine biomass, Sargassum sp., as substrate. In this case a maximum hydrogen production of 0.62 mmol was achieved in the presence of 0.13 g zeolite g-1 (VS) biomass. Due the use of a complex substrate many soluble fermentation products were formed during Sargassum sp. dark fermentation. However acetate and lactate were the most prevalent of SFP. The effect of zeolites in continuous mode, performed with glucose and arabinose as substrate (RA + G) and with only glucose (RG), was also studied. The presence of zeolites (0.26 g zeolite g-1 (VS) biomass) improve the hydrogen production rate in the two operations, reaching a maximum of 430 mL H2 L-1 d-1 and 250 mL H2 L-1 d-1, respectively. The largest amount of soluble microbial products produced for the two operations was for lactic acid. The acetate, formic acid, propionic acid and n-butyric acid formation was also observed. |
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