| 摘要: |
| [目的]在纯培养方式下,研究水稻土中铁还原菌利用葡萄糖、果糖、心肌糖、淀粉和纤维素作为惟一碳源时对异化Fe(Ⅲ)还原的影响.[方法]以Fe(OH)3为惟一电子受体,不同单糖及多糖为惟一碳源,在30℃厌氧培养过程中,测定了3株铁还原细菌的Fe(Ⅲ)还原能力,及体系中剩余还原糖含量.[结果]铁还原菌株SC-a13、SC-a18和SC-a19在LB培养基中厌氧扩繁24 h,均可达到最大生长量.3株铁还原细菌总体上利用葡萄糖、果糖和淀粉的铁还原率分别为71.03%～82.86%,80.31%～85.77%和50.81%～73.21%,而心肌糖和纤维素难以被利用.在利用葡萄糖,果糖和淀粉时,体系pH在培养2～5 d急剧降低,然后稳定在3.5～4.5,而心肌糖和纤维素几乎没有变化.Fe(Ⅲ)反应潜势总体表现为菌株SC-a18SC-a13SC-a19,Fe(Ⅲ)反应速率常数和最大反应速率出现的时间表现为SC-a13SC-a18SC-a19.[结论]葡萄糖和果糖均能作为铁还原菌株SC-a13、SC-a18和SC-a19还原Fe(OH)3的优势碳源,淀粉的利用能力次之,心肌糖和纤维素则难以被直接利用.不同铁还原菌株之间利用不同糖源的Fe(OH)3还原反应速率常数具有较大差异.体系pH降低和剩余还原糖含量,可分别作为铁还原菌是否利用糖源进行Fe(Ⅲ)还原反应及其反应能力大小判定的特征. |
| 关键词: 铁还原菌 糖类代谢 Fe(Ⅲ)还原 纯培养 |
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| 基金项目:国家自然科学基金，西北农林科技大学创新团队计划? |
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| Fe(Ⅲ) reduction characteristics of three iron reducers using different carbon sources |
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| Abstract: |
| 【Objective】 The effect of glucose,fructose,inositol,starch and cellulose as sole carbon substrates on dissimilatory iron reduction in pure culture has been investigated.【Method】 With Fe(OH)3 as sole electronic accepter,different monosaccharide and polysaccharide as sole carbon substrate,the yield of Fe(Ⅱ) and residual reductive glycose were determined during the incubation under anaerobic condition at 30 ℃.【Result】 Strain SC-a13,SC-a18 and SC-a19 attained the most growth after propagating 24 h in LB culture medium.The Fe(Ⅲ)-reducing rates of glucose,fructose and starch as a whole by the three strains were 71.03%-82.86%,80.31%-85.77% and 50.81%-73.21%respectively.However it was hard to use inositol and cellulose to reduce ferrihydrite.pH reduced rapidly in the initial 2-5 d,then stabilized from 3.5-4.5 while using glucose,fructose and starch as carbon substrates but inositol and cellulose changed little.The potential of Fe(Ⅲ)-reduction represented SC-a18>SC-a13>SC-a19;the Fe(Ⅲ)-reducing rate constant and the time corresponding to max reaction rate were SC-a13>SC-a18>SC-a19.【Conclusion】 Strain SC-a13，SC-a18 and SC-a19 from paddy soil can use glucose and fructose to reduce Fe(OH)3 well,followed by the ability to use starch,and inositol and cellulose can not be used directly.The Fe(OH)3 reduction rate using different carbon sources among distinct iron reducers has notable discrepancy.pH fall and residual reductive glycose can play as one characteristic of Fe(Ⅲ)-reducing reaction and estimate the abilities of Fe(OH)3 indirectly. |
| Key words: Fe(Ⅲ)-reducing bacterium metabolism of glucide Fe(Ⅲ) reduction pure culture |
