Studies On The Influential Factors Of Oxidation Activities And Isolation Of Methane Oxidizing Bacteria

Methane was one of many important green-house gases. It placed secondary important role in green-house effect. Approximate 60 ton methane from paddy soil that was an important biological resource of atmosphere, released from the paddy to the atmosphere every year, up to 12% of the whole world methane emission. Therefore, reducing methane production from the paddy soil was important to reduce the green-house effect, as well as promoting methane to be oxidized in the soil. At present there was no the better measure to reduce methane production, under this premise, the research was done as follows:The first aim of this paper was to breed the methane-oxidizing bacteria from the paddy soil selectively, and made sure its best temperature for growth and pH as well as the use of carbon source. There existed an efficient way of reducing the green-house effect through improving the environmental conditions of methane-oxidizing bacteria survival and the oxidized activity. Methane's biologic oxidation in the paddy soil was impelled by the methane-oxidizing bacteria. Therefore, inevitably the environmental factor of influence methane-oxidizing bacteria would affect the paddy soil oxidized methane. The second one was done about the relation between environment factors and the paddy soil oxidized methane activities, in order to provide the theoretic basis of enhancing the paddy soil oxidized methane activities and controlling methane release from the paddy soil. At present there were comparatively extensive research focusing on triazophos and acetochlor environment behaviors in soil, such as absorption, desorption, residual dynamics, degeneration and migration regulation. But there were a few studies about the impact of triazophos and acetochlor on the edaphon in soil, especially to methane-oxidizing bacteria. The final one was to study the biological effect of pesticide pollution on population quantity and activities of methane-oxidizing bacteria, in order to unveil foundation of the microbiology and the environment toxicology and reasonable use of these two pesticide. Conclusively, the results were as follows:1. A superior methane-oxidizing bacteria strain isolated from the soil (MOB₀₀₁), was pink, not transparent, bacilliform through microscope observation, and gram negative, so it was belonged to Methylamine. Though character of its shape was similar to Methylamine's Methylamines methanica, the accurate classification needed further studies. The research of MOB₀₀₁ showed that the optimum pH of MOB₀₀₁ was 7, scale of the temperature ranged from 25℃to 35℃, and the optimum temperature was 30℃, MOB₀₀₁ also could grow in the non-methane environment with low concentration Methanol, it concluded that MOB₀₀₁ was the optional nutritive methane-oxidizing bacteria.2. Research on the factors of influencing methane oxidation in the paddy soil indicated that: The edaphon was the main biological group which oxidized methane, ability to oxidize the methane was varies according to the different soil. It may be related to the physics and chemistry nature of the soil. The water content had an obvious influence on methane oxidation activities (the best water content was 25%). More or less water would inhibited oxidation activities. Scale of temperatures of the highest oxidation activities were range from 25℃to 30℃. The nitrogenous fertilizer had the inhibition to the methane oxidation activities, amid three kinds of nitrogenous fertilizer, inhibited effect of niter was the highest, sulfate ammonium was the lowest; the methane oxidation activities varied in terms of the different kinds of carbon sources. The high concentration of the methanol and glucose strongly restricted the methane-oxidizing bacteria activities. But the proper concentration of methanol may promote the methane oxidation in paddy field. The activities were the highest when pH was from 6.5 to 7.3. The research of the influence of triazophos and acetochlor on population quantity and the activeness of methane-oxidizing bacteria indicated that: triazophos promoted the reproduction and oxidization activities of methane- oxidizing bacteria in the paddy soil, and with pesticide concentration increasing, the promotion of reproduction and oxidization activities were gradually strengthened. The promotion was weakening with time going. Acetochlor inhibited the reproduction and oxidization activeness of methane-oxidizing bacteria, with pesticide concentration increasing, the inhibition of reproduction and oxidization activities was gradually weakened, but the inhibition was weakening along with time going. The oxidation activities of methane-oxidizing bacteria affected by two kinds of pesticide depended on methane-oxidizing bacteria reproduction affected by these pesticides.