温度、pH对非光合微生物菌群固碳效率的影响及其成因分析

CO2是主要的温室气体，也是地球上最丰富的碳源和可再生资源，本实验通过研究温度和pH对非光合固碳微生物固碳效率的影响，以期获得非光合固碳微生物适宜的固碳条件，并通过16SrDNA序列分析，研究了不同条件对固碳微生物群落结构的影响及其与固碳效率的相关性。结果表明，好氧／厌氧固碳微生物菌群生长的最适pH均在7左右。好氧固碳微生物菌群可在较大的温度范围（10℃-40℃）内良好生长，但其固碳速率在10℃左右时最高，之后微生物固碳速率随温度上升而下降，在40℃时，微生物固碳速率开始回升。厌氧时微生物的固碳效率随温度的变化情况与好氧时相似，但总体效果要比其在好氧时低20％～25％。由DGGE图谱及戴斯系数分析可得培养温度和pH对群落结构有显著影响，不同pH和温度条件下优势菌差异显著，这可能是固碳效率变化的重要原因之一。

Influence of temperature and pH on CO2 fixation by a non-photosynthetic microbial community and its mechanism analysis

CO2 is one of the main greenhouse gases, but it is also the most abundant carbon source and renewable source. Changes of pH and temperature affecting the CO2 fixation efficiency by non-photosynthetic microbial comrnunities were discussed in order to find an appropriate culture condition for the non-photosynthetic microbial communities which used to fix CO2. In addition, 16S rDNA sequence analysis was applied to analyze the community structure transformation between different culture conditions. The results were as follows, aerobic microbial communities grew at the highest rate when medium pH maintained at around 7. The aerobic microbial communities could grow well in a large rang of temperature （10 ℃ --40 ℃ ） and 10℃ was the optimal temperature for the aerobic microbial communities to get a higher CO2 fixation rate. The CO2 fixation rate was decreased with the opposite trend of temperature, but there is a rally at the temperature of 40 ℃. On average, the CO2 fixation efficiency of aerobic microbial communities was about 20 % -25 % higher than that of anaerobic microbial communities. DGGE pattern and Dice coefficient revealed significant differences between communities cultivated under various temperatures and medium pH. The kinds of important microorganisms varied significantly with changes of pH or temperature, which might be the most important reason for changes of CO2 fixation efficiency.