铁还原过程对栖热腔菌Thermosipho ferrireducens JL129W03^(T)的厌氧发酵代谢影响

Effect of iron reduction process on anaerobic fermentation metabolism of bacterium Thermosipho ferrireducens JL129W03^(T)

本研究以分离自西北印度洋深海热液硫化物的铁还原栖热腔菌(Thermosipho ferrireducens)JL129W03^(T)为研究对象,在以四方纤铁矿(β-FeOOH)为电子受体条件下,测定了不同培养时间的细胞生长量和主要的代谢产物,并结合其基因组信息预测了主要代谢途径。结果表明,厌氧糖酵解是该菌的主要代谢途径,发酵代谢产物包括乙醇、乙酸、乳酸、丁酸和CO_(2)。同时,该菌含有[Fe-Fe]型氢酶,可以利用厌氧发酵过程产生的还原态铁氧还蛋白获得电子产生H_(2)。在培养基中添加四方纤铁矿后,促进了菌株的最大细胞生长量(3.17×10^(7)cells/mL至2.19×10^(8)cells/mL),也促进了菌株对淀粉和纤维素的利用率(分别提高了100%和34%)。同时,培养基中添加四方纤铁矿后,菌株JL129W03的乙醇产量增加了76%,而丁酸的产量却降低了73%,对H_(2)、乙酸、乳酸的产生影响较小。本研究对了解Thermosipho ferrireducens JL129W03^(T)的生理代谢特点和进一步应用开发清洁能源(H_(2)、乙醇等)奠定了基础。

In order to study the effect of iron reduction process on the anaerobic fermentation of Thermosiphio ferrireducens JL129W03^(T),which was isolated from the deep-sea hydrothermal sulfide in the Northwest Indian Ocean,the cell growth and metabolites of strain JL129W03 with/withoutβ-FeOOH as electron acceptor were quantitatively analyzed by cell counting,liquid chromatography and gas chromatography.The main metabolic pathway of JL129W03 was also analyzed based on its genome and it is anaerobic glycolysis pathway as result.It produces pyruvate resulting in the final metabolites of ethanol,acetic acid,lactic acid,butyric acid and CO_(2).We also found that H_(2)is produced by[Fe-Fe]hydrogenase which obtains electrons from the oxidation process of reduced ferredoxin.The addition ofβ-FeOOH to the medium significantly promoted the cell growth(from 3.17×10^(7)cells/mL to 2.19×10^(8)cells/mL)and the utilization of carbohydrates(such as starch and cellulose;increased 100%and 34%,respectively).The production of ethanol was significantly promoted(increased 76%)withβ-FeOOH as electron acceptor,while the production of butyric acid was inhibited(reduced 73%).This study was helpful for understanding the physiological metabolism of strain JL129W03 and its further application for hydrogen and ethanol production.