【作者】 黄杰勋；

【导师】 孙宝林；

【作者基本信息】 中国科学技术大学 ， 微生物学， 2009， 博士

【摘要】 由于近年来全球范围的石油能源的短缺和全球变暖导致的极端天气带来的巨大影响,易获得的生物质作为可替代型能源越来越受到关注。微生物燃料电池作为利用电化学活性微生物作为催化剂的产电装置,能将生物质中有机物的化学能直接转化为电能。相比传统的间接能源转化形式,微生物燃料电池这种从原料直接转化电能的方式在理论上将会有更高的能量效率。然而,在实际应用中由于存在诸多限制因素微生物燃料电池产生的电功率输出还停留在较低的水平,有待进一步的优化以提高微生物燃料电池的整体性能。以乳酸盐作为电子供体和电极作为电子受体在微生物燃料电池内进行富集,从厦门近海样品中共筛选得到五株产电菌。通过在微生物燃料电池中的产电验证,所有的菌株均具有良好的产电性能。通过16S rRNA和gyrB基因序列的分析以及DNA-DNA杂交,将菌株S1、S5和EP1在种属上分别鉴定为Shewanella decolorationis, Shewanella aquimarina和Shewanella marisflavi。DNA-DNA杂交显示S2和S4属于同一种内两菌株,以S4作为模式菌株,综合系统发育分析和表型特征数据,将该菌分类鉴定为Shewanella属内的新种。此外,利用Fe(III)氧化物作为电子受体从温泉口样品中分离到一株超嗜热菌。EP1菌株由多相分析鉴定为属于Shewanella marisflavi,能在高达1488 mM的离子强度下利用乳酸盐作为电子供体还原Fe(III)和产电。利用该菌在MFC中产电,离子强度为291 mM下测量到的最大电功率为3.6 mW/m2,离子强度提高到1146 mM时,最大电功率增长到9.6 mW/m2,提高167%。然而,进一步提高离子强度到1488 mM,最大电功率下降到5.2 mW/m2。对内电阻的定量分析发现将电极液离子强度从291 mM增加到1488 mM电极液电阻从1178 ?减小到50 ?。这些结果表明分离特异的微生物菌种能有效地提高微生物燃料电池的性能。更多还原

【Abstract】 Due to the recent woldwide shortage of fossil energy and significant impacts of global warming which often brings the extreme weather events, readily available biomass has attract much attention as an alternative energy source. Microbial fuel cells (MFCs) are devices that convert chemical energy directly from organic matter in the biomass using electrochemically active bacteria as catalysts to generate electrical energy. Compared to the traditional indirect transformation of energy, this direct conversion from primary fuel to electricity makes it theoretically possible to achieve a higher efficiency. In practice, however, the power output of MFC is still maintained at a comparatively lower level due to many constraints and need further optimization to increase the overall performance of MFCs.By enrichment with lactate as electon donor and electrode as electon accepter in MFCs, five current producing bacteria were isolated from the coastal samples collected in Xiamen. All of the isolated can generate considerable electricity current in MFCs. Sequnce analysis of 16S rRNA and gyrB gene and DNA-DNA hybridization identified strain S1, S5 and EP1 belong to Shewanella decolorationis, Shewanella aquimarina and Shewanella marisflavi, respectively. Using DNA-DNA hybridization, strain S2 and S4 were palced within one species. On the basis of phylogenetic and phenotypic characteristics, S4, choosen as type strain, was classified in the genus Shewanella as a distinct novel species. In addition, using Fe(III) oxide as electron acceptor one hyperthermophile was isolated from hot spring samples.Strain EP1, belonging to Shewanella marisflavi based on polyphasic analysis, which could reduce Fe(III) and generate power at a high ionic strength of up to 1488 mM (8% NaCl) using lactate as the electron donor. Using this bacterium, a measured maximum power density of 3.6 mW/m2 was achieved at an ionic strength of 291 mM. The maximum power density was increased by 167% to 9.6 mW/m2 when ionic strength was increased to 1146 mM. However, further increasing the ionic strength to 1488 mM resulted in a decrease in power density to 5.2 mW/m2. Quantification of the internal resistance distribution revealed that electrolyte resistance was greatly reduced from 1178 to 50 ? when ionic strength increased from 291 to 1488 mM. These results indicate that isolation of specific bacterial strains can effectively improve power generation in some MFC applications.更多还原