菌株Enterococcus sp.ZQ21异化还原Fe(Ⅲ)及产氢性质分析

Fe(Ⅲ) reduction and hydrogen production by Fe(Ⅲ)-reducing bacterium Enterococcus sp. ZQ21

一些发酵型异化铁还原细菌同时具有异化铁还原与产氢的能力,该类细菌在环境污染修复的同时能够解决能源问题,具有广阔应用前景。本文以海洋沉积物中异化铁还原细菌Enterococcus sp.ZQ21为研究对象,设置不同形态Fe(Ⅲ),分析菌株ZQ21异化铁还原与产氢性质。结果表明,当氢氧化铁和柠檬酸铁为电子受体时,菌株ZQ21以柠檬酸铁为电子受体时Fe(Ⅲ)还原效率较高,其酶活性分别为3.66 U和4.40 U。同时,菌株ZQ21在异化铁还原培养体系中具有产氢能力,以柠檬酸铁和氢氧化铁为电子受体进行厌氧发酵培养时,体系累积产氢量分别为(1395.30±4.79)m L/L和(174.30±3.23)mL/L,均显著高于对照组[(23.20±2.09) mL/L]。通过液相发酵产物分析,在柠檬酸铁和氢氧化铁不同形态Fe(Ⅲ)培养条件下,菌株ZQ21分别表现出乙醇型发酵和丁酸型发酵产氢代谢类型。菌株Enterococcus sp. ZQ21具有异化铁还原和产氢能力,进一步拓宽发酵型异化铁还原细菌种质资源。

Some anaerobic fermentation bacteria wtih simultaneous dissimilatory iron reduction and hydrogen production have been paid more and more attention for dual characteristics of energy-saving and environmentfriendliness. A Fe(Ⅲ)-reducing bacterium, Enterococcus sp. ZQ21 isolated from marine sediment was used to analyze the characteristics of microbial Fe(Ⅲ) reduction coupled to hydrogen production. Strain ZQ21 could reduce Fe(Ⅲ) with iron reductase activity of 3.66 U when iron hydroxide was as electron acceptor. While, using ferric citrate, strain ZQ21 had the higher iron reductase activity of 4.40 U. In addition, strain ZQ21 was capable of hydrogen production under the culture condition of Fe(Ⅲ) reduction. Hydrogen production of strain ZQ21 was(1395.30 ± 4.79) mL/L, which significantly increased hydrogen production compared the control [(23.20 ±2.09) mL/L]. According to the gas chromatography analysis, for strain ZQ21, ethanol and butyric acid became the major soluble production when electron acceptors were ferric citrate and iron hydroxide respectively. This result indicates that strain ZQ21 has the ability of high microbial Fe(Ⅲ) reduction and hydrogen production,which will provide evidence for the application of dissimilatory Fe(Ⅲ)-reducing bacteria for the characteristics of energy-saving.