青藏高原土壤柴油降解菌的筛选及降解实验研究

青藏高原北麓河地区土壤为典型的低温土壤环境,夏季高温季节表层土壤(5 cm处)温度仅为9℃,中层(20 cm处)为7.5℃,而40 cm处仅为4℃左右。土壤高温季节为7月中旬至9月上旬,而10月至来年6月土壤日平均温度下降为0℃以下。针对青藏高原低温土壤环境,在北麓河试验现场进行人工模拟柴油污染,16个月后采集污染土样,进行土著低温菌的复合筛选,柴油菌的筛选驯化温度为10℃。经过4次转接复合培养驯化后,菌液中微生物数量可达2.7×1012CFU/mL。筛选后的柴油降解菌90%以上为杆状菌,长度为2~3μm,少见球菌,其直径约为0.5μm。通过柴油摇瓶模拟降解实验,17 d后柴油去除率可达到62%。研究为青藏高原低温条件下的土壤柴油污染土著微生物修复提供了研究基础。

SCREENING OF DIESEL DEGRADATION BACTERIA FROM SOIL IN TIBETAN PLATEAU AND ITS DEGRADATION PERFORMANCE ON DIESEL

The soil in Beiluhe area of Qinghai-Tibet Plateau is the typical soil in low temperature environment.In Summer,the temperature is only9 ℃ at the soil surface(5 cm),7.5 ℃ in middle layer (20 cm),and about 4 ℃ in layer under 40 cm.The high temperature lasts from middle July to early September,but in September to October of the next year,the average temperature decreases below 0 ℃.In this study,artificial simulation of the diesel pollution was operated in test field in Beiluhe in Tibet Plateau.After 16 months,the polluted soil sample was taken back to screen the native low temperature bacteria.The temperature in screening and taming of diesel bacteria domestication was 10 ℃.After four times of cultivation and domestication,the microbial number in bacteria liquid could reach 2.7 × 1012 CFU/mL.More than 90％ of the screened diesel oil degradation bacteria was rod-shaped bacteria,and the length was about 2 ～ 3 microns;but cocci was rarely found with the diameter of about 0.5 microns.By diesel shake flask simulation degradation experiment,on the 17th day,removal rate of diesel oil could reach 62％.