KINETICS OF CH4 OXIDATION IN OXIC SOILS EXPOSED TO AMBIENT AIR OR HIGH CH4 MIXING RATIOS
KINETICS OF CH4 OXIDATION IN OXIC SOILS EXPOSED TO AMBIENT AIR OR HIGH CH4 MIXING RATIOS
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DOI：
10.1111/j.1574-6968.1992.tb05783.x
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发表时间：
1992-10-01
影响因子：
4.2
通讯作者：
CONRAD, R
中科院分区：
文献类型：
--
作者：
BENDER, M;CONRAD, R
在新鲜状态和高甲烷混合比（20%）下预培养3周后，测定了不同好氧土壤（耕作形成土、森林淋溶土、草甸形成土、水稻土）的甲烷氧化动力学参数（K（m），V（max），表观阈值= Th（a））。预孵育导致甲烷氧化细菌的最可能数量增加。在新鲜土壤中，CH 4氧化遵循Michaelis-Menten动力学，具有低K（m）（30-51 nM CH 4），低V（max）（0.7-3.6 nmol CH 4 h-1g-1dw土壤）和低Th（a）（0.2-2.7 ppmv CH 4）。在预培养土壤中，CH 4氧化表现出两相动力学，其中两个不同的CH 4饱和曲线明显叠加在一起。Eadie-Hofstee图显示了两种具有不同动力学参数的活性：低K（m）的高亲和力活性（13-470 nM CH 4），低V（max）（2.1-150.0 nmol CH_4 h ~（-1）g ~（-1）dw）和低Th（a）（0.3- 4.1ppmvCH_4）与新鲜土壤中的动力学参数相似;低亲和活性，高K（m）（1740-27900 nM CH_4）、高V（max）（270-3690 nmol CH_4 h ~（-1）g ~（-1）dw）和高Th（a）（11-45 ppmv CH_4），与甲烷氧化细菌已知的动力学参数相似。在永久暴露于高CH 4混合比（> 5%CH4）的深层天然气源上方的土壤中也观察到低亲和力活性。作为甲烷氧化菌培养的细菌可能是负责低亲和力的活动，这是典型的暴露于高CH 4混合比的土壤。然而，负责高亲和力活性的细菌仍然是未知的。这种活动是典型的土壤暴露于环境中的CH 4混合比例。高亲和力和低亲和力的活动都受到抑制高压灭菌和乙炔。
The kinetic parameters of CH4 oxidation (K(m), V(max), apparent threshold = Th(a)) were measured using different oxic soils (cultivated cambisol, forest luvisol, meadow cambisol, paddy soil) both in a fresh state and after 3 weeks preincubation under high CH4 mixing ratios (20%). The preincubation resulted in an increase of the most probable number of methanotrophic bacterial. In fresh soils, CH4 oxidation followed Michaelis-Menten kinetics with a low K(m) (30-51 nM CH4), low V(max) (0.7-3.6 nmol CH4 h-1g-1dw soil), and low Th(a) (0.2-2.7 ppmv CH4). In preincubated soils, CH4 oxidation exhibited biphasic kinetics in which two different CH4 saturation curves were apparently superimposed on each other. Eadie-Hofstee plots of the data showed two activities with different kinetic parameters: a high-affinity activity with low K(m) (13-470 nM CH4), low V(max) (2.1-150.0 nmol CH4 h-1g-1dw) and low Th(a) (0.3-4.1 ppmv CH4) being similar to the kinetic parameters in fresh soils; and a low-affinity activity with high K(m) (1740-27900 nM CH4), high V(max) (270-3690 nmol CH4 h-1g-1dw) and high Th(a) (11-45 ppmv CH4) being similar to the kinetic parameters known from methanotrophic bacteria. The low-affinity activity was also observed in a soil over a deep natural gas source which was permanently exposed to high CH4 mixing ratios (> 5% CH4). Bacteria culturable as methanotrophs are probably responsible for the low-affinity activity which is typical for the soils exposed to high CH4 mixing ratios. However, the bacteria responsible for the high-affinity activity are still unknown. This activity is typical for the soils exposed to only ambient CH4 mixing ratios. Both high- and low-affinity activities were inhibited by autoclaving and by acetylene.