温度对土壤中多环芳烃缺氧微生物降解的影响

Effect of Temperature on Anoxic Biodegradation of Polycyclic Aromatic Hydrocarbons in Soil

该研究以PAHs污染土壤为研究对象,研究了不同温度条件下土壤中PAHs的缺氧生物降解规律。结果表明,土壤中细菌总数随着温度的升高而增加。经过180 d缺氧培养后,当温度从20℃升至30、40、50和60℃时,土壤中的细菌总量较20℃处理组土壤中的细菌总量分别增加了0.07、0.37、0.55和0.60个数量级。原土中微生物优势种群为变形杆菌门和放线菌门。而随着温度的升高,厚壁菌门逐渐转变为优势种群。经过180 d缺氧培养,当温度从20℃上升至60℃时,厚壁菌门的相对丰度由11.27%上升到90.83%。不同温度条件下PAHs降解效率基本遵循60℃>50℃>40℃>30℃>20℃的顺序,不同环数PAHs的降解效率基本遵循三环>四环>五六环的顺序。当培养温度为60℃时,PAHs的缺氧降解效果最好,三环、四环、五六环和TPAHs去除率分别达到了70.73%、55.99%、16.96%、42.26%,与20℃相比分别提高了30.69%、28.38%、9.56%、21.01%。

In this study, PAHs aging contaminated soil was used as the research object to study the anoxic biodegradation of PAHs in soil at different temperatures. The results showed that the total number of bacteria in soil increased with the increase of temperature. After 180 days of anoxic culture, when the temperature increased from 20 ℃ to 30 ℃, 40 ℃, 50 ℃ and 60 ℃,the total amount of bacteria in the soil increased by 0.07, 0.37, 0.55 and 0.60 orders of magnitude respectively compared with that in the 20 ℃ treatment group. The dominant microbial populations in the original soil are Proteobacteria and Actinobacteria. With the increase of temperature, Firmicutes gradually changed into the dominant population. After 180 days of hypoxia culture, when the temperature increased from 20 ℃ to 60 ℃, the relative abundance of Firmicutes increased from 11.27% to90.83%. Under different temperature conditions, the degradation efficiency of PAHs follows the order of 60 ℃>50 ℃>40 ℃>30 ℃>20 ℃, and the degradation efficiency of PAHs with different ring numbers basically follows the order of three rings >four rings > five and six rings. When the culture temperature was 60 ℃, the anoxic degradation effect of PAHs was the best.The degradation rates of 3-, 4-, 5-and 6-PAHs andΣPAHs reached 70.73%, 55.99%, 16.96% and 42.26%, respectively, and increased by 30.69%, 28.38%, 9.56% and 21.01% respectively compared with 20 ℃.