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摘要：纯化趋磁细菌A.ferrooxidans细胞内能合成纳米级磁性颗粒四氧化三铁，即磁小体。磁小体作为一种新型的生物纳米磁性材料，近年来备受关注。本次课题通过测量细菌生长曲线及菌体干、湿细胞产率，研究铁源种类，铁源浓度，不同酸碱性以及磁场等培养条件对A.ferrooxidans菌生长的影响。结果表明，随着铁源浓度的提高，A.ferrooxidans的生长速度、达到稳定期的细胞浓度以及菌体干、湿细胞产率都有所提高；以FeSO4为铁源时，当浓度值由20g/L增加至40g/L、A.ferrooxidans稳定期湿细胞产率由232mg/L增加至409mg/L、干细胞产率由20mg/L增加至29.5mg/L；以柠檬酸铁为铁源时，当浓度值由浓度由40g/L增加至50g/L、A.ferrooxidans稳定期湿细胞产率由232mg/L增加至410mg/L、干细胞产率由18.5mg/L增加至28mg/L；以磁黄铁矿为铁源时、当浓度由l00g/L增加至200g/L， A.ferrooxidans稳定期湿细胞产率由230.5mg/L增加至397mｇ/L、干细胞产率由16mg/L增加至27.5mg/L；本次实验条件下的最适铁源为FeSO4,最佳pH值为2.0左右，并且pH值与最佳值偏离越大者各项生长指标越低。23473
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毕业论文关键词：趋磁细菌；磁小体；趋磁性；四氧化三铁
Effects of culture conditionson the synthesis of magnetosomes by A.ferrooxidans
Abstract：Magnetotactic bacteria A.ferrooxidans purifid can synthesize nanoscale magnetic particles Fe3O4 named magnetic bodies in its cells. Magnetic bodies as a new biological nano magnetic materials have attracted much attention in recent years. This topic studies the effects of culture conditions like kinds of iron source, iron source concentration, different acidity and magnetic field on the growth of A.ferrooxidans bacteria through the measurement of bacterial growth curve and cell dry-wet yield. The results show that, with the increase of the concentration of iron sources, the growth rate, the cell concentration in stable stage and cell dry- wet yield of A.ferrooxidans are improved. Using FeSO4 as the iron source, when the concentration increases from 20g/L to 40g/L, A.ferrooxidans wet-cell yield in stable stage increases from 232mg/L to 409mg/L, dry-cell yield increases from 20mg/L to 29.5mg/L. Using ferric citrate as the iron source, when the concentration increases from 40g/L to 50g/L, A.ferrooxidans wet-cell yield in stable stage increases from 232mg/L to 410mg/L, dry-cell yield increases from 18.5mg/L to 28mg/L. Using pyrrhotite as the iron source, when the concentration increases from 100g/L to 200g/L, A.ferrooxidans wet-cell yield in stable stage increases from 230.5mg/L to 397mg/L, dry-cell yield increases from 16mg/L to 27.5mg/L. Under the condition of this experiment, the optimum iron source is FeSO4, the optimum pH value is about 2, and the pH value deviates from it more greater the growth index is more lower.
KeyWords：Magnetotactic bacteria；Magnetosomes；Magnetotactic；Fe3O4
目录
1绪言 1
1.1 课题背景 1
1.2 文献综述 2
1.2.1 趋磁细菌的发展概况 2
1.2.2 嗜酸性氧化亚铁硫杆菌的研究现状 3
1.2.3磁小体的形貌特征 4
1.2.4磁小体的合成 5
1.2.5生物矿化作用合成磁小体的意义 7
1.2.6前景展望 8
1.3研究目的及先进性 9
2实验方案及步骤 11
2.1 实验原材料 11
2.1.1 菌株及培养基 11
2.1.2实验器材 11
2.2 实验方案 11
2.2.1铁源种类的影响 12
2.2.2 Fe2+浓度的影响 12
2.2.3 pH的影响 12
2.2.4 磁场的影响 13
2.3试验方法 13