| 摘要: |
| [目的]明确不同来源的铁还原微生物对纤维素的利用特征,探讨不同水稻土中铁还原微生物群落利用纤维素功能的差异,以及电子供体浓度与氧化铁还原的关系.[方法]以来源于吉林、天津、四川的水稻土为供试材料,分别采用土壤泥浆培养、水稻土微生物群落厌氧培养及纯培养试验方法,研究了添加纤维素作为电子供体对氧化铁微生物还原过程的影响.[结果]土壤泥浆厌氧恒温培养试验表明,与不添加纤维素的对照相比,添加5～40 g/L纤维素后,四川、吉林和天津水稻土中Fe(Ⅲ)还原的最大潜势分别增加10.5%～16.0%,-1.9%～0.6%及5.3%～14.4%,反应速率常数分别增加19%～89%,53%～96%及75%～164%,最大反应速率(Vmax)分别增加37%～109%,41%～79%及74%～148%.不同纤维素处理间的pH值有明显变化.在接种吉林、天津、四川和湖南水稻土微生物群落的处理中,当纤维素质量浓度为2～10 g/L时,其Fe(Ⅱ)的累积量分别为341.62～493.87,90.75～246.78,164.02～540.16和235.47～488.75 mg/L.随着添加纤维素浓度的增大,Vmax亦呈增大趋势.12株铁还原菌株的纯培养试验中,有4株菌的Fe(Ⅲ)还原率达到20.9%～23.6%,6株菌的Fe(Ⅲ)还原率为16.17%～19.94%,2株菌的Fe(Ⅲ)还原率仅为9.64%和9.66%.[结论]添加纤维素可使Fe(Ⅲ)还原的最大反应速率及速率常数增加,添加的纤维素浓度越大,其增加幅度越大.不同水稻土微生物群落,利用纤维素还原铁的能力具有明显差异.与接种不同水稻土微生物群落的铁还原过程相比,纯培养试验的Fe(Ⅱ)累积量明显较低,12株铁还原菌株直接利用纤维素的能力也较为有限. |
| 关键词: 水稻土 厌氧培养 微生物的铁还原 纤维素 |
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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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| Effect of the cellulose as the electron donor on the Fe(Ⅲ) reduction |
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| Abstract: |
| 【Objective】 In order to ascertain the utilization character of cellulose by the iron-reducing microbial from different sources,the experiment was done to find out the difference of cellulose usage by microbial communities from different paddy soils and the relationship between the concentration of electron donor and iron reduction.【Method】 The paddy soils were used as test materials from Jilin,Tianjin and Sichuan.The effect of the cellulose as an electronic donor on the iron oxides reduction process was studied with the methods of slurries incubation, paddy soil microbial community anaerobic culture and pure culture.【Result】 The results show that,compared to control,the biggest Fe(Ⅲ) reduction potential in paddy soil from Sichuan,Jilin and Tianjin was enhanced separately by 10.5%-16.0%,-1.9%-0.6% and 5.3%-14.4%when 5-40 g/L cellulose was added;The rate constant respectively increased by 19%-89%,53%-96% and 75%-164% and the biggest rate increased by 37%-109%,41%-79% and 74%-148% respectively.pH was significantly different in different cellulose treatments.In the experiment of inoculating microbial community from Jilin,Tianjin,Sichuan and Hunan paddy soils,Fe(Ⅱ) of accumulated changes were separately 341.62-493.87,90.75-246.78,164.02-540.16 and 235.47-488.75 mg/L when the concentration of cellulose added was 2-10 g/L.With the increasing concentration of cellulose added,Vmax increased.In pure culture of 12 bacteria of iron reduction,four Fe (Ⅲ) reduction rate was 20.9%-23.6%,six the 16.17%-19.94%,two only 9.64% and 9.66%. 【Conclusion】 The max-rate of Fe(Ⅲ) reduction increased with the added cellulose,so did the rate constant.The extent increased with the concentration of the added cellulose.There was significant difference between the iron-reduction ability of the microbial communities using cellulose.Compared with the process of iron-reduction of inoculating different paddy soil microbial communities,Fe(Ⅱ) cumulant was significantly low in pure culture experiment.The ability of the 12 iron-reduction microbial using cellulose was limited. |
| Key words: paddy soil anaerobic culture microbial iron reduction cellulose |
