环境胁迫因子对固定菌修复污染土壤效果的研究

Immobilized bacteria for degradation of PAHs in soil

通过对环境胁迫因子参数的不同设定,对固定菌修复污染土壤效果进行了研究。结果显示,当环境胁迫因子温度(高温40℃和低温15℃)、酸碱度(pH=4和pH=9)及重金属(Cd和Pb)存在时,对固定菌降解污染物的影响并不大,而游离菌降解率却有一定的下降趋势。进一步观察了固定化载体内部微观结构,为固定菌用于有机污染土壤的异位修复提供了一定的理论基础。

Three PAHs degrading bacteria isolates were immobilized in PVA-based carrier granules （2.5 mm diameter） alone and together for degradation of pyrene and benzo（a） pyrene （100 mg/L） in soil samples. The immobilized bacteria were more effective in degrading pyrene than benzo（a） pyrene,and the granules carrying mixed bacteria were more effective than those carrying single isolates. Hostile environmental conditions of temperature （40℃ and 15℃） ,pH （4 and 9）,and presence of heavy heavy metal （0.1 mmol/L of Cd and Pb） had little adverse effects on biodegradation by immobilized bacteria. The carrier granules were porous allowing easy entry of the bacteria, dissolved oxygen, substrates and nutrients to the interior sites. The findings are useful for the application of immobilized microorganisms in off-site bioremediation of organic contaminated soils.