| 摘要: |
| [目的]对水稻土中铁还原菌进行分离纯化,比较不同培养基的分离效果,研究不同菌株的铁还原特征.[方法]以四川和江西水稻土为材料.采用PTYG固体平板培养基及柠檬酸铁固体培养基(斜面)分离出兼性厌氧和严格厌氧的菌株,并通过柠檬酸铁液体培养基及Fe(OH)3培养基进行铁还原能力测定,比较不同菌株的Fe(Ⅲ)还原率大小、铁还原特征曲线,以及分别在LB液体培养基和柠檬酸铁液体培养基中的生长曲线.[结果]在以葡萄糖为碳源时,来源于江西水稻土的8个菌株对柠檬酸铁的利用率较高,铁还原率为84.34%～93.81%,而对Fe(OH)3的还原率为71.07%～90.90%;来源于四川水稻土的8个菌株对柠檬酸铁的还原率为83.78%～93.52%,而对Fe(OH)3的还原率为88.19%～99.84%.严格厌氧菌株的铁还原速率较快,在培养3 d后20个菌株的铁还原率都在90%以上.利用柠檬酸铁的铁还原率为90.49%～97.93%,利用Fe(OH)3的为94.03%～99.57%.在LB液体培养基及柠檬酸铁液体培养基中,不同菌株的对数生长期为10～25 h,前者的延滞期较短,而后者的细胞产量较大.[结论]由四川和江西水稻土中获得了对柠檬酸铁和Fe(OH)3具有高效利用率的铁还原菌株,其中严格厌氧菌株对2种铁源的利用率均明显大于兼性厌氧菌株.兼性厌氧铁还原菌株为革兰氏阴性芽孢杆菌,严格厌氧铁还原菌株为革兰氏阳性,有芽孢,属梭状杆菌.铁还原菌的生长与Fe(Ⅲ)的还原具有耦合关系. |
| 关键词: 水稻土 铁还原菌 分离纯化 铁还原率 |
| DOI： |
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| 基金项目:国家自然科学基金项目(40271067，40741005) |
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| Isolation of iron-reducing bacteria in paddy soil and its Fe(Ⅲ) reduction potential analysis |
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| Abstract: |
| 【Objective】The study isolated Fe(Ⅲ)-reducing bacterium from paddy soil,compared the different isolating results of different dilution factor,and studied the Fe reducing-characters of different strains.【Method】 Fe(Ⅲ)-reducing bacterium was isolated with PTYG plate and Fe(Ⅲ)-citrate medium from paddy soil of Jiangxi and Sichuan Province and the ability of Fe(Ⅲ)-reducing potential of bacterium was identified by Fe(OH)3culture and Fe(Ⅲ)-citrate medium method.The rate of Fe(Ⅲ)-reducing and the character curve of Fe(Ⅲ)-reduction and growth of different bacteria were compared.【Result】 When using glucose as carbon source,8 strains facultative anaerobic bacteria from paddy of Jiangxi could reduce Fe(Ⅲ)-citrate quickly and the rate of Fe(Ⅲ)-citrate reduction was between 84.34%-93.81%,but the rate of Fe(OH)3reduction was low,just between 71.07%-90.90%.8 strains facultative anaerobic bacteria from paddy soil of Sichuan had efficient abilities to reduce Fe(Ⅲ) and the rate of Fe(Ⅲ)-citrate reduction was between 83.78%-93.52%,and the rate of Fe(OH)3reduction between 88.19%-99.84%.The strictly anaerobic bacteria from paddy soil of Jiangxi and Sichuan Province all had efficient ability to reduce Fe(Ⅲ).20 strains strictly anaerobic bacteria could reduce Fe(Ⅲ) quickly,the rate of Fe(Ⅲ)-citrate reduction was between 90.49%-97.93% and the rate of Fe(OH)3 reduction between 94.03%-99.57%.The lag phase of different bacteria was almost between 10-25 h in LB culture and Fe(Ⅲ)-citrate medium.Bacteria had short lag phase in LB culture,and the outputs of cells were larger in Fe (Ⅲ)-citrate medium. 【Conclusion】 Bacteria strains which can reduce Fe were isolated from paddy soil of Jiangxi and Sichuan,and the isolated bacteria showed high utilization rate of Fe(Ⅲ)-citrate and Fe(OH)3.Strictly anaerobic iron reducing bacteria's utilization rate of the two Fe resources were both higher then that of facultative anaerobic bacteria's.Facultative anaerobic bacteria were rod-shaped gram-negative bacteria with spores;strictly anaerobic bacteria were gram-positive bacteria with spores,belonging to fusiform bacillus.The Fe(Ⅲ)-reduction was coupled with the growth of bacteria. |
| Key words: paddy soil Fe(Ⅲ)-reduction bacterium isolation Fe(Ⅲ)-reduction rate |
